Literatura científica selecionada sobre o tema "Substrate shifts"

Urban habitats are drastically modified from their natural state, creating unique challenges and selection pressures for organisms that reside in them. We compared locomotor performance of Anolis lizards from urban and forest habitats on tracks differing in angle and substrate, and found that using artificial substrates came at a cost: lizards ran substantially slower and frequently lost traction on man-made surfaces compared to bark. We found that various morphological traits were positively correlated with sprint speed and that these same traits were significantly larger in urban compared to forest lizards. We found that urban lizards ran faster on both man-made and natural surfaces, suggesting similar mechanisms improve locomotor performance on both classes of substrate. Thus, lizards in urban areas may be under selection to run faster on all flat surfaces, while forest lizards face competing demands of running, jumping and clinging to narrow perches. Novel locomotor challenges posed by urban habitats likely have fitness consequences for lizards that cannot effectively use man-made surfaces, providing a mechanistic basis for observed phenotypic shifts in urban populations of this species.

Haynes, K. M., Preston, M. D., McLaughlin, J. W., Webster, K. and Basiliko, N. 2015. Dissimilar bacterial and fungal decomposer communities across rich to poor fen peatlands exhibit functional redundancy. Can. J. Soil Sci. 95: 219–230. Climatic and environmental changes can lead to shifts in the dominant vegetation communities present in northern peatland ecosystems, including from Sphagnum- to vascular-dominated systems. Such shifts in vegetation result in changes to the chemical quality of carbon substrates for soil microbial decomposers, with leaves and roots deposited in the peat surface and subsurface that potentially decompose faster. This study characterized the bacterial and fungal communities present along a nutrient gradient ranging from rich to poor fen peatlands and assessed the metabolic potential of these communities to mineralize a variety of organic matter substrates of varying chemical complexity using substrate-induced respiration (SIR) assays. Distinct microbial communities existed between rich, intermediate and poor fens, but SIR in each of the three sites exhibited the same pattern of carbon mineralization, providing support for the concept of functional redundancy, at least under standardized in vitro conditions. Preferential mineralization of simple organic substrates in the rich fen and complex compounds in the poor fen was not observed. Similarly, no preference was given to “native” organic matter extracts derived from each fen, with microbial communities opting for the most bioavailable substrate. This study suggests that soil bacteria and fungi might be able to respond relatively rapidly to shifts in vegetation communities and subsequent changes in the quality of carbon substrate additions to peatlands associated with environmental and climatic change.

Abstract laminated composites on silicon or magnesium oxide substrates. The magnetoelectric voltage coefficient is calculated as function of interface coupling factor k, volume ratio of piezoelectrics to piezomagnetic, and volume ratio of substrates to composite. It was found that the magnetoelectric voltage coefficient decreases as the interface coupling factor k weakens, while the volume ratio of piezoelectrics to piezomagnetic vmax shifts to lead-rich compositions. The magnetoelectric voltage coefficient of laminated composites decreases sharply with increasing substrates thickness ratio, which shows strong substrate clamping effect to the magnetoelectric composite.

Understanding the biodegradation potential of river bacterioplankton communities is crucial for watershed management. We investigated the shifts in bacterioplankton metabolic profiles along the salinity gradient of the Caloosahatchee River Estuary, Florida. The carbon source utilization patterns of river bacterioplankton communities were determined by using Biolog EcoPlates. The number of utilized substrates was generally high in the upstream freshwater dominated zone and low in the downstream zone, suggesting a shift in metabolic profiles among bacterioplankton assemblages along the estuarine gradient. The prokaryotic cell numbers also decreased along the estuarine salinity gradient. Seasonal and site-specific differences were found in the numbers of utilized substrates, which were similar in summer and fall (wet season) and winter and spring (dry season). Bacterioplankton assemblages in summer and fall showed more versatile substrate utilization patterns than those of winter and spring communities. Therefore, our data suggest that microbial metabolic patterns in the subtropical estuary are likely influenced by the water discharge patterns created by dry and wet seasons along the salinity gradient.

We investigated the effect of the basal plane dislocation (BPD) density in 4H-silicon carbide (SiC) substrates on the forward voltage (Vsd) degradation of body-diodes. Using reflection X-ray topography, the BPD density was automatically estimated from the substrates prior to fabrication of metal–oxide–semiconductor field-effect transistors (MOSFETs). A strong positive correlation was found between the Vsd shift, which was calculated from the difference before and after forward bias stress at 160 A/cm2 for ~500 hours, and the BPD density of the substrate. We show that it is possible to predict Vsd shifts from the BPD densities of SiC substrates prior to the fabrication of MOSFETs. In addition, we examined the origin of stacking faults (SFs) as a result of the application of forward bias stress. We presume that SFs are formed by BPDs converted to threading edge dislocations at the epi/sub interface, as well as by BPDs penetrating into the epitaxial layer.

We have studied the energy shifts of indirect excitons consisting of an electron in one quantum well and a hole in an adjacent quantum well. Several surprising effects occur: (1) a very strong blue shift with increasing intensity of resonant laser excitation, (2) a very strong red shift with weak magnetic field, and (3) very low-frequency (sub-Hz) fluctuations of the spectral position at high excitation density. We discuss the effect of screening by carriers excited in the substrate material.

Aging presumably initiates shifts in substrate oxidation mediated in part by changes in insulin sensitivity. Similar shifts occur with cardiac hypertrophy and may contribute to contractile dysfunction. We tested the hypothesis that aging modifies substrate utilization and alters insulin sensitivity in mouse heart when provided multiple substrates. In vivo cardiac function was measured with microtipped pressure transducers in the left ventricle from control (4–6 mo) and aged (22–24 mo) mice. Cardiac function was also measured in isolated working hearts along with substrate and anaplerotic fractional contributions to the citric acid cycle (CAC) by using perfusate containing 13C-labeled free fatty acids (FFA), acetoacetate, lactate, and unlabeled glucose. Stroke volume and cardiac output were diminished in aged mice in vivo, but pressure development was preserved. Systolic and diastolic functions were maintained in aged isolated hearts. Insulin prompted an increase in systolic function in aged hearts, resulting in an increase in cardiac efficiency. FFA and ketone flux were present but were markedly impaired in aged hearts. These changes in myocardial substrate utilization corresponded to alterations in circulating lipids, thyroid hormone, and reductions in protein expression for peroxisome proliferator-activated receptor (PPAR)α and pyruvate dehydrogenase kinase (PDK)4. Insulin further suppressed FFA oxidation in the aged. Insulin stimulation of anaplerosis in control hearts was absent in the aged. The aged heart shows metabolic plasticity by accessing multiple substrates to maintain function. However, fatty acid oxidation capacity is limited. Impaired insulin-stimulated anaplerosis may contribute to elevated cardiac efficiency, but may also limit response to acute stress through depletion of CAC intermediates.

The objective of this research is to implement monolithic analog phase shifters based on barium strontium titanate (BST) coated sapphire substrates for IEEE 802.11b wireless local area network (WLAN) applications. It has been known that several BST thin film properties such as high relative permittivity, electric field dependence, fast polarization response, relatively low loss, and high breakdown field, allow for miniaturization and high performance of analog phase shifters. Before attempting to implement BST phase shifters, coplanar waveguides (CPWs) and interdigital capacitors (IDCs) based on various BST compositions and thicknesses have been developed and characterized to capitalize on the electrical properties of BST thin films. Based on the characteristics of BST thin films, two design topologies have been studied to implement phase shifters. The first topology is a reflection-type structure. The reflection-type phase shifter composed of a 3-dB coupler and two identical reflective terminations has provided a large phase shift with a relatively low insertion loss. The second topology is an all-pass network structure. The all-pass network phase shifter consists of only lumped elements so that one can shrink in size of devices. The total chip area of the all-pass network phase shifter is only 2.6 mm * 2.2 mm with a loss figure-of-merit (FOM) of more than 69 deg/dB at 2.4 GHz. This is the smallest size and the best performance obtained to date for BST phase shifters in the 2.4 GHz band and comparable or even better than the state of the GaAs MMIC phase shifters. The nonlinear response of the all-pass network phase shifter also was investigated with two-tone intermodulation distortion (IMD) measurement. Furthermore, the all-pass network phase shifter was studied to ascertain a design to ensure minimum performance variation over a range of temperature and to determine which BST composition performed best in the face of temperature variations. Compact beamforming networks (BFNs) for WLAN systems using client-based smart antennas have been demonstrated to validate the feasibility of BST technology for WLAN applications. The two-element BFNs have been shown to increase throughput and network capacity by rejecting interference.

Les systèmes de communications sans fils actuels imposent des contraintes très sévères en termes de la capacité du canal, la qualité de transmission tout en gardant les niveaux d'interférences et multi-trajets assez faibles. De telles contraintes ont rendu les antennes multifaisceaux un élément essentiel dans ces systèmes. Parmi les techniques permettant de réaliser une antenne multifaisceaux (sans avoir recours aux systèmes à balayages électroniques), un réseau d'antennes élémentaires est associé à un réseau d'alimentation (une matrice) à formation de faisceau (Beam Forming Network-BFN). Parmi les différents types de ces matrices, la matrice de Butler a reçu une attention particulière. Ceci est dû au fait qu'elle est théoriquement sans pertes et qu'elle emploie un nombre minimum de composants (coupleurs et déphaseurs) afin de générer l'ensemble de faisceaux orthogonaux demandé (avec l'hypothèse que le nombre de faisceau est une puissance de 2). Néanmoins, la matrice de Butler a un problème de conception majeur. Ce problème réside dans la structure de la matrice qui renferme des croisements ce qui a été adressé par différents travaux de recherches dans la littérature. Les Guide Intégré au Substrat (GIS) offrent des caractéristiques intéressants pour la conception des composants microondes et millimétriques faciles à intégrer sur un même support avec d'autres composants planaires. Les composants à base de GIS combinent les avantages des guides d'ondes rectangulaires, comme leur grand facteur de qualité Q, leur faibles pertes tout en étant compatible avec les technologies à faibles coûts comme le PCB et le LTCC. Vus ses caractéristiques attrayants, la technologie GIS devient un bon candidat pour la réalisation des matrices multifaisceaux faciles à intégrer avec d'autres systèmes en technologies planaires ou à base de guide GIS. Dans cette thèse, de nouveaux composants passifs sont développés en exploitant la technologie GIS en multicouches en vue de la réalisation d'une matrice de Butler 4x4 compacte et large bande. Les composants recherchés sont donc des coupleurs et des déphaseurs ayant des performances large bande en termes des amplitudes des coefficients de transmissions et les phases associés tout en gardant de faibles niveaux de pertes et de bonnes isolations. Différents techniques pour l'implémentation de déphaseurs large bande en technologie GIS sont présentés. Une nouvelle structure à base d'une propagation composite : main gauche main droite (Composite Right/Left- Handed, CRLH) dans un guide d'onde est proposée. La structure consiste d'un guide d'onde monocouche ayant des fenêtres inductives et des fentes transversales à réactances capacitives pour synthétiser l'inductance parallèle et la capacité série main gauche, respectivement. La structure est adaptée pour les réalisations de déphaseurs compacts en technologie GIS. Bien que les pertes d'insertions restent dans le même ordre de grandeur de celles des structures CRLH à base d'éléments non-localisés, ces niveaux de pertes restent relativement grands par rapport aux applications nécessitant plusieurs déphaseurs. Les déphaseurs à bases de GIS ayant des longueurs égales et des largeurs variables sont ensuite abordés. Ce type de déphaseur est effectivement très adapté à la technologie GIS qui permet des réalisations de parcours avec différentes formes (parcours droits, courbés, coudés, ..) tout en assurant des différences de phase large bande. Afin de satisfaire de faibles pertes d'insertions pour une large dynamique de phase, la longueur de ces déphaseurs est en compromis avec les variations progressives des différentes largeurs associées aux valeurs de déphasages requises. Une transition large bande, double couche et à faible perte est ainsi proposée. La transition est analysée à partir de son circuit électrique équivalent afin d'étudier les performances en termes de l'amplitude et la phase du coefficient de transmission par rapport aux différents paramètres structurels de la transition. Cette transition est ensuite exploitée pour développer un déphaseur à trois couches, large bande, en GIS. La structure consiste effectivement d'un guide d'onde replié à plusieurs reprises sur luimême selon la longueur dans une topologie trois couches à faibles pertes. De nouveaux coupleurs double couche en GIS sont également proposés. Pour les applications BFNs, une structure originale d'un coupleur large bande est développée. La structure consiste de deux guides d'onde parallèles qui partagent leur grand mur ayant une paire de fentes inclinées et décalées par rapport au centre de la structure. Une étude paramétrique détaillée est faite pour étudier l'impact des différents paramètres des fentes sur l'amplitude et la phase du coefficient de transmission. Le coupleur proposé a l'avantage d'assurer une large dynamique de couplage ayant des performances larges bandes en termes des amplitudes et les phases des coefficients de transmission avec de faibles pertes et de bonnes isolations entre le port d'entré et celui isolé. D'autre part, contrairement à d'autres travaux antérieurs et récents qui souffraient d'une corrélation directe entre la phase en transmission et le niveau de couplage, la structure proposée permet de contrôler le niveau de couplage en maintenant presque les mêmes valeurs de phase en transmission pour différents niveaux de couplage. Ceci le rend un bon candidat pour les BFNs déployant différents coupleurs telle la matrice de Nolen. Une deuxième structure originale d’un coupleur bibande est également proposée. La structure consiste de deux coupleurs concentriques en guide nervuré intégré au substrat avec un motif innovant de démultiplexage à base de GIS. Ce coupleur a été développé conjointement avec M. Tarek Djerafi de l’Ecole Polytechnique de Montréal dans un cadre de collaboration avec le Prof. Ke Wu. Finalement, pour l'implémentation de la matrice de Butler, la topologie double couche est explorée à deux niveaux. Le premier consiste à optimiser les caractéristiques électriques de la matrice, tandis que le second concerne l'optimisation de la surface occupée afin de rendre la matrice la plus compacte possible sans dégrader ses performances électriques. D'une part, la structure double couche présente une solution intrinsèque au problème de croisement permettant ainsi une plus grande flexibilité pour la compensation de phase sur une large bande de fréquence. Ceci est réalisé par une conception adéquate de la surface géométrique sur chaque couche de substrat et optimiser les différentes sections de GIS avec les différents parcours adoptés. La deuxième étape consiste effectivement à optimiser la surface sur chaque couche en profitant de la technologie GIS. Ceci consiste à réaliser des murs latéraux communs entre différents chemin électrique de la matrice en vue d'une compacité optimale. Les deux prototypes de matrices de Butler 4x4 sont optimisés, fabriqués et mesurés. Les résultats de mesures sont en bon accord avec ceux de la simulation. Des niveaux d'isolations mieux que - 15 dB avec des niveaux de réflexions inférieurs à -12 dB sont validés expérimentalement sur plus de 24% de bande autour de 12.5 GHz. Les coefficients de transmission montrent de faibles dispersions d'environ 1 dB avec une moyenne de -6.8 dB, et 10° par rapport aux valeurs théoriques, respectivement, sur toute la bande de fréquence<br>Multibeam antennas have become a key element in nowadays wireless communication systems where increased channel capacity, improved transmission quality with minimum interference and multipath phenomena are severe design constraints. These antennas are classified in two main categories namely adaptive smart antennas and switched-beam antennas. Switched-beam antennas consist of an elementary antenna array connected to a Multiple Beam Forming Network (M-BFN). Among the different M-BFNs, the Butler matrix has received particular attention as it is theoretically lossless and employs the minimum number of components to generate a given set of orthogonal beams (provided that the number of beams is a power of 2). However, the Butler matrix has a main design problem which is the presence of path crossings that has been previously addressed in different research works. Substrate Integrated Waveguide (SIW) features interesting characteristics for the design of microwave and millimetre-wave integrated circuits. SIW based components combine the advantages of the rectangular waveguide, such as the high Q factor (low insertion loss) and high power capability while being compatible with low-cost PCB and LTCC technologies. Owing to its attractive features, the use of SIW technology appears as a good candidate for the implementation of BFNs. The resulting structure is therefore suitable for both waveguide-like and planar structures. In this thesis, different novel passive components (couplers and phase shifters) have been developed exploring the multi-layer SIW technology towards the implementation of a two-layer compact 4×4 Butler matrix offering wideband performances for both transmission magnitudes and phases with good isolation and input reflection characteristics. Different techniques for the implementation of wideband fixed phase shifters in SIW technology are presented. First, a novel waveguide-based CRLH structure is proposed. The structure is based on a single-layer waveguide with shunt inductive windows (irises) and series transverse capacitive slots, suitable for SIW implementations for compact phase shifters. The structure suffers relatively large insertion loss which remains however within the typical range of non-lumped elements based CRLH implementations. Second, the well-known equal length, unequal width SIW phase shifters is discussed. These phase shifters are very adapted for SIW implementations as they fully exploit the flexibility of the SIW technology in different path shapes while offering wideband phase characteristics. To satisfy good return loss characteristics with this type of phase shifters, the length has to be compromised with respect to the progressive width variations associated with the required phase shift values. A twolayer, wideband low-loss SIW transition is then proposed. The transition is analyzed using its equivalent circuit model bringing a deeper understanding of its transmission characteristics for both amplitude and phase providing therefore the basic guidelines for electromagnetic optimization. Based on its equivalent circuit model, the transition can be optimized within the well equal-length SIW phase shifters in order to compensate its additional phase shift within the frequency band of interest. This twolayer wideband phase shifter scheme has been adopted in the final developed matrix architecture.This transition is then exploited to develop a three-layer, multiply-folded waveguide structure as a good candidate for compensated-length, variable width, low-loss, compact wideband phase shifters in SIW technology. Novel two-layer SIW couplers are also addressed. For BFNs applications, an original structure for a two-layer 90° broadband coupler is developed. The proposed coupler consists of two parallel waveguides coupled together by means of two parallel inclined-offset resonant slots in their common broad wall. A complete parametric study of the coupler is carried out including the effect of the slot length, inclination angle and offset on both the coupling level and the transmission phase. The first advantage of the proposed coupler is providing a wide coupling dynamic range by varying the slot parameters allowing the design of wideband SIW Butler matrix in two-layer topology. In addition, previously published SIW couplers suffer from direct correlation between the transmission phase and the coupling level, while the coupler, hereby proposed, allows controlling the transmission phase without significantly affecting the coupling level, making it a good candidate for BFNs employing different couplers, such as, the Nolen matrix. A novel dual-band hybrid ring coupler is also developed in multi-layer Ridged SIW (RSIW) technology. This coupler has been jointly developed with Tarek Djerafi in a collaboration scenario with Prof. Ke Wu from the Ecole Polytechnique de Montréal. The coupler has an original structure based on two concentric rings in RSIW topology with the outer ring periodically loaded with radial, stub-loaded transverse slots. A design procedure is presented based on the Transverse Resonance Method (TRM) of the ridged waveguide together with the simple design rules of the hybrid ring coupler. A C/K dual band coupler with bandwidths of 8.5% and 14.6% centered at 7.2 GHz and 20.5 GHz, respectively, is presented. The coupler provides independent dual band operation with low-dispersive wideband operation. Finally, for the Butler matrix design, the two-layer SIW implementation is explored through a two-fold enhancement approach for both the matrix electrical and physical characteristics. On the one hand, the two-layer topology allows an inherent solution for the crossing problem allowing therefore more flexibility for phase compensation over a wide frequency band. This is achieved by proper geometrical optimization of the surface on each layer and exploiting the SIW technology in the realization of variable width waveguides sections with the corresponding SIW bends. On the other hand, the two-layer SIW technology is exploited for an optimized space saving design by implementing common SIW lateral walls for the matrix adjacent components seeking maximum size reduction. The two corresponding 4×4 Butler matrix prototypes are optimized, fabricated and measured. Measured results are in good agreement with the simulated ones. Isolation characteristics better than -15 dB with input reflection levels lower than -12 dB are experimentally validated over 24% frequency bandwidth centered at 12.5 GHz. Measured transmission magnitudes and phases exhibit good dispersive characteristics of 1dB, around an average value of -6.8 dB, and 10° with respect to the theoretical phase values, respectively, over the entire frequency band

This thesis presents various integrated antenna solutions for different types of systems and applications, e.g. wireless sensors, broadband handsets, advanced base stations, MEMS-based reconfigurable front-ends, automotive anti-collision radars, and large area electronics. For wireless sensor applications, a T-matched dipole is proposed and integrated in an electrically small body-worn sensor node. Measurement techniques are developed to characterize the port impedance and radiation properties. Possibilities and limitations of the planar inverted cone antenna (PICA) for small handsets are studied experimentally. Printed slot-type and folded PICAs are demonstrated for UWB handheld terminals. Both monolithic and hybrid integration are applied for electrically steerable array antennas. Compact phase shifters within a traveling wave array antenna architecture, on single layer substrate, is investigated for the first time. Radio frequency MEMS switches are utilized to improve the performance of reconfigurable antennas at higher frequencies. Using monolithic integration, a 20 GHz switched beam antenna based on MEMS switches is implemented and evaluated. Compared to similar work published previously, complete experimental results are here for the first time reported. Moreover, a hybrid approach is used for a 24 GHz switched beam traveling wave array antenna. A MEMS router is fabricated on silicon substrate for switching two array antennas on a LTCC chip. A concept of nano-wire based substrate integrated waveguides (SIW) is proposed for millimeter-wave applications. Antenna prototypes based on this concept are successfully demonstrated for automotive radar applications. W-band body-worn nonlinear harmonic radar reflectors are proposed as a means to improve automotive radar functionality. Passive, semi-passive and active nonlinear reflectors consisting of array antennas and nonlinear circuitry on flex foils are investigated. A new stretchable RF electronics concept for large area electronics is demonstrated. It incorporates liquid metal into microstructured elastic channels. The prototypes exhibit high stretchability, foldability, and twistability, with maintained electrical properties.<br>wisenet

Wastes with high organic content, such as food waste, are produced worldwide and can cause serious pollution problems when poorly managed. Thus, there is the need for the implementation of environmental friendly treatment systems for organic wastes. Anaerobic digestion has the potential to contribute for the sustainable treatment of these wastes while producing biogas which provides a renewable energy source, methane (CH4). In this study, a two-stage anaerobic system was operated treating three different fruit pulp wastes (peach, raspberry and white guava) in a sequential operation. The effect of substrate shifts and different operational conditions, such as hydraulic retention time (HRT), organic loading rate (OLR) and pH on the system’s performance was assessed. The shift of substrates caused no long-term instability issues. The differences observed in the acidogenic performance in terms of gas production between substrates were considerable. Conversely, only slight differences were observed in fermentation products (FP) concentration and profiles. No evident association was found between pH and HRT/OLR changes on FP concentration and profiles in the range studied. Overall, the sugar removal efficiencies obtained were between 93.8 – 97.8% and the acidification degree varied between 53.7% – 76.4%. In regard to the methanogenic reactor, biogas production (3.6 – 12.8 L d-1) increased as OLR increased up to 7.4 g COD L-1, while CH4 yield (0.30 – 0.37 L CH4 g-1 COD) and content (75.9– 80.6%) remained approximately constant. Maximal chemical oxygen demand (COD) removal efficiency (around 93%) was achieved at HRTs of 8.6 and 5 days (OLR of 1.9 – 3.7 g COD L-1 d-1). Currently, there is the need to develop effective and economical viable solutions for biogas upgrading. Thus, gas permeation studies using mixed-matrix membranes (MMMs) with two different metal organic frameworks (MOFs) - MIL-53 and MOF-5 - were carried out in other to assess the potential for CH4 and carbon dioxide (CO2) separation. Matrimid®5218 with 10% (w/w) MIL-53 membrane showed the best performance among the membranes tested.

碩士<br>明新科技大學<br>電子工程研究所<br>96<br>Abstract Along with manufacturing process technique continuously innovative, including the thickness of gate oxidation layer, chip size, channel length, etc., all unceasingly downsize fast. However, the decrease of the operation voltage of the device is unable to keep up with it. Therefore, the electric field of acceleration carrier at short-channel site is already several times of that at long channel device. So, the hot carrier effect and the short channel effect will be more serious. Improving the short channel effect, the structure of lightly doped drain (LDD) is a good way of general adoption which can be effectively improved because of the threshold voltage roll-off and the drain Induced barrier lowering (DILB), causing the drop of device characteristics. However LDD doping concentration and implemented distribution energy may also generate the device drawback and then influence the reliability of device. How to take channel device defect and reliability into account is very important. Source/Drain (S/D) pole location can be basically divided into two parts, extension S/D and contact S/D. The CMOS manufacturing process adopting LDD design in early days was for improving the hot carrier effect of device. The method is at both ends in MOS channel, implementing into a lower quantity of the source /drain concentration below spacer, in order to reduce the electric field. But in the advanced manufacturing process of CMOS device, due to the descend of the supply voltage (Vcc), the very shallow junction of the source/drain is no longer the main point of the reliability. The speed of the device is impressively focused focal in this moment. Thus, increasing the implementation amount of LDD, and reducing the resistance of source/drain, are the essential methodology in fact. This is why people change that with the source / drain extension (SDE). Because the channel length of device is smaller and smaller, the junction concentration profile is high and steep. Coming from drain voltage to generate very high electric field causing the direct band to band tunneling current (DBTB) can result in extra S/D current. Generally the shallow junction, points out the entire junction depth of source/drain. After the junction becoming shallow, the resistance of source/drain will raise and this effect disobeys our request to high-speed device again. Exalt the doping concentration and descending the resistances of source/drain at shallow-junction technique are also a tough task. Because this source/drain extension can effectively reduce the reliability problem of the hot carrier effect (HCE), by measuring the device with UMC 90 nm manufacturing process and assisting the process simulation with ISE software, to verify the intensity of internal electric fields of the device, are the chief targets of this thesis research. The purpose of this thesis lies in studying the reliability analysis of 90 nm SDE NMOSFETs. At present the device size is tiny to the nanometer grade (L<100 nm). The vertical and horizontal high electric field in operation will make it easier to cause the generation of hot carrier and result in gate oxide leakage. Particularly, when the device gets into a 90 nm size or below, the thickness of gate oxide will physically tend near 1.6 nm, the moving carriers can more easily tunneling oxide layer. The tunnel phenomenon of gate oxide stressed by hot carrier degradation will be gradually obvious. This thesis measured the hot carrier effect of device under UMC 90 nm manufacturing process and set up some modes to fit the simulation of 90 nm NMOS device mold, 90 nm NMOS under different S/D Extension doping concentrations. The electric field at SDE would change under the different VD voltages. This thesis is totally divided into 5 chapters; chapter 1 is a brief introduction. Chapter 2 is device physics. Chapter 3 simulates for the manufacturing process, chapter 4 describes experimental purposes and simulating results. Chapter 4 will also discuss the relationship of ISUB measurement, SDE manufacturing process simulation plus related analysis, and how to truly apply on the improvement of the manufacturing process. Chapter 5 is a summary.

碩士<br>國立交通大學<br>電信工程研究所<br>104<br>In this thesis, a V-band phase shifters and a V-band mechanical switches are proposed using the substrate integrated waveguide (SIW). The substrate integrated waveguide is manufactured on a Rogers RT-Duroid 5880® low loss substrate with a dielectric constant of 2.2 and a thickness of 10 mil. The single-pole-single-throw (SPST) and single-pole-double-throw (SPDT) switches are proposed with a center frequency of 60 GHz where the so-called cross centered copper ring structure are adopted. The on and off of the switches are mechanically controlled by a piece of conducting material to lift or contact the specified area of the switch. On the other hand, the proposed phase shifter cascades three different phase shifters which include a 90 degree digital phase shifter, a 180 degree digital phase shifter and a 90 degree tunable phase shifter. Finally, the proposed switches and the proposed phase shifter are measured by a network analyzer with the V-band (WR-15) waveguide extenders through the newly developed SIW to rectangular waveguide transition. The advantage of this newly developed transition is no electrical contact with the metal of the rectangular waveguide.

碩士<br>國立成功大學<br>電機工程學系<br>88<br>In this thesis, we attempt to explore the basic properties of the transmission type planar phase shifter on the BSTO ceramics substrates and try to find out design rule at the same time. At beginning, we focus on the planar phase shifter which has 50Ωcharacteristic impedance. The ceramics substrate usually has the intrinsically high dielectric constant maybe few hundred or few thousand or even more. For example, there was only 21μm line width for substrate of Ba0.6Sr0.4TiO3 doped with 10 wt％ ZrO2 which relative dielectric constant is 1100 and thickness is 1mm. At the scale, the dimensions of surface roughness and air gaps are compatible with the line width of microstrip line. Therefore we used low impedance one ( about 5Ω)to reduce the affect of those factors as discussion above. For example, there was 1.21 mm line width for substrate of Ba0.6Sr0.4TiO3 doped with 5 wt％ Al2O3 which relative dielectric constant is 750, thickness is 0.83 mm. A phase shift of 59.2° was obtained at 2 GHz under bias voltage of 1.8 KV. There was highly linear relationship between phase shift and bias voltage。

Phased array antennas, capable of controlling the direction of their radiated beam, are demanded by many conventional as well as modern systems. Applications such as automotive collision avoidance radar, inter-satellite communication links and future man-portable satellite communication on move services require reconfigurable beam systems with stress on mobility and cost effectiveness. Microwave phase shifters are key components of phased antenna arrays. A phase shifter is a device that controls the phase of the signal passing through it. Among the technologies used to realize this device, traditional ferrite waveguide phase shifters offer the best performance. However, they are bulky and difficult to integrate with other system components. Recently, ferrite material has been introduced in Low Temperature Co-fired Ceramic (LTCC) multilayer packaging technology. This enables the integration of ferrite based components with other microwave circuitry in a compact, light-weight and mass producible package. Additionally, the recent concept of Substrate Integrated Waveguide (SIW) allowed realization of synthesized rectangular waveguide-like structures in planar and multilayer substrates. These SIW structures have been shown to maintain the merits of conventional rectangular waveguides such as low loss and high power handling capabilities while being planar and easily integrable with other components. Implementing SIW structures inside a multilayer ferrite LTCC package enables monolithic integration of phase shifters and phased arrays representing a true System on Package (SoP) solution. It is the objective of this thesis to pursue realizing efficient integrated phase shifters and phased arrays combining the above mentioned technologies, namely Ferrite LTCC and SIW. In this work, a novel SIW phase shifter in ferrite LTCC package is designed, fabricated and tested. The device is able to operate reciprocally as well as non-reciprocally. Demonstrating a measured maximum reciprocal phase shift of 132o and maximum non-reciprocal shift of 118o at 12 GHz. Additionally a slotted SIW antenna is designed and integrated with the phase shifter in an array format, demonstrating a beam scanning of ± 15o. The design is highly suitable for mobile automotive radars and satellite communications systems.

The purpose of this chapter is to familiarize the reader with the basic electrical patterns of the electroencephalogram (EEG). Brain cells (mainly neurons and glia) are organized in multiple levels of intricate networks. The cellular membranes are semipermeable media between extracellular and intracellular solutions, populated by ions and other electrically charged molecules. This represents the basis of electrical currents flowing across cellular membranes, further generating electromagnetic fields that radiate to the scalp electrodes, which record changes in the activity of brain cells. This chapter presents these concepts together with the mechanisms of building up the EEG signal. The chapter discusses the various behavioral conditions and neurophysiological mechanisms that modulate the activity of cells leading to the most common EEG patterns, such as the cellular interactions for alpha, beta, gamma, slow, delta, and theta oscillations, DC shifts, and some particular waveforms such as sleep spindles and K-complexes and nu-complexes.

The shifted chessboard or café wall illusion yields to analysis at the two poles of the practice of vision science: bottom-up, pursuing its course from the visual stimulus into the front end of the visual apparatus, and top-down, figuring how the rules governing perception might lead to it. Following the first approach, examination of the effects of light spread in the eye and of nonlinearity and center-surround antagonism in the retina has made some inroads and provided partial explanations; with respect to the second, principles of perspective and of continuity and smoothness of contours can be evoked, and arguments about perception as Bayesian inference can be joined. Insights from these two directions are helping neurophysiologists in their struggle to identify a neural substrate of the phenomenon Münsterberg described in 1897.

Many of the same behavioural and brain disturbances observed in addiction are also seen in obesity and binge-eating disorder. This suggests that there are shared neural substrates between substance addiction and compulsive food consumption. Food intake and appetite are regulated by numerous appetite hormones that exert their effects through brain systems involved in reward sensitivity, stress, impulsivity, and compulsivity. There is now emerging evidence that appetite hormones (e.g. ghrelin, glucagon-like peptide-1, orexin) can modulate addictive behaviours (e.g. craving) and the intake of alcohol and drugs. Therefore, there is an emerging shift into a new field of testing drugs that affect appetite hormones and their receptors in the brain, and their use in regulating the brain mechanisms that lead to relapse in addiction disorders.

When dietary carbohydrate is restricted and protein consumed in moderation, the evolutionarily-conserved ketogenic metabolic machinery awakens. After just a few days circulating ketones increase by an order of magnitude, and over several weeks there is a profound shift away from glucose as the primary energy substrate to the preferred use of fatty acids and ketones. This metabolic process is known as keto-adaptation. The deemphasis on insulin-dependent glucose uptake into cells and concomitant increase in fat oxidation has important implications in management of insulin resistance and its secondary manifestations, which are all functionally carbohydrate-intolerant conditions. The health implications of keto-adaptation are profound. In a definitive break from traditional groupthink, athletes are now experimenting with diets low in carbohydrate in an effort to improve their health, body composition, performance, and recovery. This chapter explores the rationale for the construct of keto-adaptation as a tool for achieving general well-being and improved performance.

AbstractElectrochemical deposited (ECD) thick film copper on silicon substrate is one of the most challenging technological brick for semiconductor industry representing a relevant improvement from the state of art because of its excellent electrical and thermal conductivity compared with traditional compound such as aluminum. The main technological factor that makes challenging the industrial implementation of thick copper layer is the severe wafer warpage induced by Cu annealing process, which negatively impacts the wafer manufacturability. The aim of presented work is the understanding of warpage variation during annealing process of ECD thick (~20 µm) copper layer. Warpage has been experimental characterized at different temperature by means of Phase-Shift Moiré principle, according to different annealing profiles. A linear Finite Element Model (FEM) has been developed to predict the geometrically stress-curvature relation, comparing results with analytical models.

The maintenance of life requires a constant supply of substrate for the generation of energy and preservation of the structure of cells and tissues. The process in principle is simple, yet the individual metabolic pathways and the regulation of substrate fluxes through these pathways can be complex. Energy is derived when fuel substrates are oxidized to carbon dioxide and water in the presence of oxygen, generating adenosine triphosphate (ATP). A portion of the ingested foodstuff is also utilized, either directly or after transformation into other substrates, to repair and replace cell membranes, structural proteins, and organelles. The remainder is stored as potential energy in the form of glycogen or fat. Under normal circumstances, each individual remains in a near-steady state where weight and appearance are stable over prolonged periods. In the short term, fuel metabolism changes dramatically several times a day during alternating periods of feeding and fasting. An anabolic phase begins with food ingestion and lasts for several hours. Energy storage occurs during this period when caloric intake exceeds caloric demands. The catabolic phase usually begins 4 to 6 hours after a meal and lasts until the person eats once again. During this phase, utilization shifts from exogenous to endogenous fuels, a change heralded by the mobilization of substrate stored in liver, muscle, and adipose tissue. Both anabolic and catabolic phases are characterized by specific biochemical processes regulated by distinct hormonal profiles. In the anabolic phase that follows ingestion of a mixed meal, substrate flux is directed from the intestine through the liver to storage and utilization sites. Glucose, triglyceride, and amino acid concentrations increase in plasma, whereas those of fatty acids, ketones (acetoacetic and β -hydroxy-butyric acids), and glycerol decrease. Both glycogen and protein synthesis begin in liver and muscle, while fatty acid synthesis and triglyceride esterification are stimulated in hepatocytes and adipose tissue. In the catabolic phase, the biochemical activities are reversed and the flux of fuel is directed from storage depots to liver and other utilization sites.

The traditional electrochemical techniques are based on the measurement of current and potential, and, in the case of liquid electrodes, of the surface tension. While such measurements can be very precise, they give no direct information on the microscopic structure of the electrochemical interface. In this chapter we treat several methods which can provide such information. None of them is endemic to electrochemistry; they are mostly skillful adaptations of techniques developed in other branches of physics and chemistry. The scanning tunneling microscope (STM) is an excellent device to obtain topographic images of an electrode surface . The principal part of this apparatus is a metal tip with a very fine point, which can be moved in all three directions of space with the aid of piezoelectric crystals. All but the very end of the tip is insulated from the solution in order to avoid tip currents due to unwanted electrochemical reactions. The tip is brought very close, up to a few Ångstroms, to the electrode surface. When a potential bias ΔV, usually of the order of a few hundred millivolts, is applied between the electrode and the tip, the electrons can tunnel through the thin intervening layer of solution, and a tunneling current is observed. The situation is illustrated in Fig. 15.2: A potential energy barrier exists between the tip and the substrate. Application of a bias potential shifts the two Fermi levels of the tip and of the substrate. Electrons can tunnel from the metal with the higher Fermi level through the barrier to empty states on the other metal. Roughly speaking, electrons with energies between the two Fermi levels can be transferred. A detailed calculation shows that the current is proportional to the electronic density of states at the Fermi level of the substrate. The tip is moved slowly in the yz direction parallel to the metal surface, and simultaneously the distance x from the electrode is adjusted in such a way that the tunneling current is constant (constant-current mode).

&lt;em&gt;Abstract&lt;/em&gt;.—Little is known about the movement and habitat use of Alabama Bass &lt;em&gt;Micropterus henshalli&lt;/em&gt; and Redeye Bass &lt;em&gt;M. coosae&lt;/em&gt;, especially in response to altered flow regimes resulting from hydropeaking operations. Therefore, 22 Alabama Bass and 20 Redeye Bass were implanted with radio tags and tracked every 3 weeks for 37 weeks from December 2010 to September 2011 to describe seasonal patterns in movement and habitat use in the Tallapoosa River, Alabama, below R. L. Harris Dam. Additionally, fish of each species were tracked weekly every 2 h over the course of 10 h to assess the effects of altered flows on movement and habitat use by the two species during different periods of the hydrograph (base, rising, peak, and falling flows). Movement of both species was strongly associated with season, with the highest movement in the spring. Total home range (95%) and core areas (50%) of both species were similar, but Redeye Bass total home range was inversely related to fish size. Alabama Bass were typically found in fine-sediment substrates and increasingly used more woody debris for cover from winter to summer, whereas Redeye Bass were typically found in rocky substrate and only used woody debris in summer. Neither Alabama Bass nor Redeye Bass daily movement appeared to be affected by the altered flow; however, Alabama Bass were found closer to shore in vegetated or woody debris habitat during high flows in spring and summer. In contrast, Redeye Bass showed little lateral movement in the river or change in habitat use in response to higher flows in most seasons but, similar to Alabama Bass, were found in shoreline vegetated habitats more often during high flows in spring. These shifts in habitat during different flows should be further investigated to evaluate possible life-history strategies.

The biological functions of proteins all depend on their highly specific interactions with other molecules, and the understanding of the molecular basis of the specificity of these interactions is an important part of the effort to understand protein structure-function relationships. NMR spectroscopy can provide information on many different aspects of protein-ligand interactions, ranging from the determination of the complete structure of a protein-ligand complex to focussing on selected features of the interactions between the ligand and protein by using “reporter groups” on the ligand or the protein. It has two particular advantages: the ability to study the complex in solution, and the ability to provide not only structural, but also dynamic, kinetic and thermodynamic information on ligand binding. Early analyses of ligand binding (Jardetzky and Roberts, 1981) focused on measurements of relaxation times, chemical shifts and coupling constants, which gave relatively limited, although valuable, structural information. More recently, it has become possible to obtain much more detailed information, due to the extensive use of nuclear Overhauser effect measurements and isotope-labeled proteins and ligands; a number of reviews of this area are available (Feeney and Birdsall, 1993; Lian et al, 1994; Wand and Short, 1994; Petros and Fesik, 1994; Wemmer and Williams, 1994). In this article, we describe some recent work from our laboratory which illustrates the use of NMR spectroscopy to obtain structural and mechanistic information on relatively large enzyme-substrate and proteinprotein complexes. A number of species of pathogenic bacteria, notably Streptococci and Staphylococci, have proteins on their surface that bind immurioglobulins (reviewed in Boyle (1990)). Protein A from S. aureus and protein G from species of Streptococci are widely used as imrnunological tools and are the most extensively studied of these antibody-binding proteins. A detailed understanding of the binding mechanisms of these proteins is important, not only for providing us with the structural basis for their functions, but also as a contribution toward understanding the general rules of protein-protein interactions.

The structural habitat of terrestrial urban environments can differ drastically from environments less impacted by human activities. Whether or not urban species use anthropogenic structures, they are subject to novel selection pressures to effectively locomote. Urban environments are distinctly more open than non-urban habitats, they offer few refuges, and habitat space is patchy with clustered perches. Animals must either change their behaviour to use only natural substrates or contend with manufactured substrates. Arboreal species are particularly impacted because the anthropogenic structures with which they interact, even if infrequently, differ from trees in structural, material, and surface properties. The chapter explores potential adaptive responses to the spatial structure and properties of climbing substrates in urban environments relevant to terrestrial and climbing locomotion. For each, the authors first discuss differences between urban and non-urban terrestrial habitats relevant to locomotion. They then discuss how these differences influence behaviour and locomotor demands, providing a mechanism through which natural selection shapes morphology. Lastly, they discuss the morphological traits most likely to be impacted by these altered demands and predict how natural selection may affect these traits in urban environments based on biomechanical principles. As there have been very few studies investigating urban morphological adaptation related to locomotion, the chapter draws on trait–environment relationships in natural environments. The discussion provides a starting point for developing rigorous hypotheses about functionally relevant trait shifts in urban environments and future directions for investigating locomotor adaptations in urban species.

Abstract Backside failure analysis techniques rely heavily on transmission of near infrared (IR) radiation through the silicon substrate. This statement applies both to emission techniques and active laser probing. Heavy doping of substrates causes them to become highly absorptive in the near IR due to band gap shifts, which effects phonon-assisted absorption, and to free-carrier absorption. Substrate thinning is often required to allow adequate optical transmission. This paper describes an empirical approach to determining the absorption coefficient in a heavily doped substrate and use of the coefficient in determining the amount of substrate thinning required.

Acoustic metamaterials display unusual mechanical wave manipulation behavior not seen in natural materials. In this study, nonlinear metamaterials with passive, amplitude-activated directional bandgaps are investigated. Test articles are constructed by installing periodic arrays of mass-loaded dome resonators on a square polycarbonate substrate. These resonators display nonlinear softening response with increase in excitation amplitude. Experiments conducted by mounting the test articles on low-stiffness boundaries along two adjacent sides and applying mechanical excitations at the opposite corner. A mechanically-staged laser vibrometer mounted overhead was used to make noncontact measurements at discrete plate and resonator locations. Measured displacement transmissibility verify the existence and extent of bandgap frequency ranges as well as amplitude-activated shifts in their bounds. Moreover, by tailoring the pattern of resonators within the array, preferential steering, focusing and selective beaming of waves within tunable frequency ranges depending on their amplitude are shown to be possible. Steady-state spatial maps depicting the displacement transmissibility field were generated from experiments and correlated with simulations to bring out underlying mechanisms. In addition, both lumped parameter and continuum models are considered to aid the design of scalable, passive adaptive metamaterial waveguides for applications ranging from seismic wave mitigation to MEMS transduction.

In the present work, a novel fabrication technique of inverted trapezoidal microstructures on a silicon substrate is presented. The novel microstructures caused the inherently hydrophilic silicon surface to become hydrophobic without the use of coating or thin film deposition. The microstructures were fabricated on a Silicon On Insulator (SOI) wafer through steps of photolithography, dry/wet etching, and bounding. Starting with a (100) plane SOI wafer, squares were patterned into a nitrite etch mask. Potassium hydroxide (KOH) anisotropic wet etchant was then used to etch the wafer, as a result created pits with flat sloping {111}-oriented sidewalls and a flat (100)-oriented bottom of the silicon device layer (i.e., at SiO2 layer). To get the inverted trapezoids, wafer bonding was carried out after etching, and the handle wafer along with the SiO2 layer were completely etched to expose the small openings of the trapezoids. SEM images were taken to investigate the surface and to measure the dimensions of the square openings from both sides before and after bonding. Contact angle measurements demonstrated the ability of the novel surfaces to form Cassie wetting states with a liquid droplet, sustaining large contact angles above 90 degrees, whereas bare silicon surfaces were measured to have contact angles of around 40 degrees. Shifts in contact angles were attributed to air entrapment.

A combination of two optical methods — Fourier-domain optical coherence tomography (FD-OCT) and photo-stimulated luminescence piezo-spectroscopy (PLPS) is used as a non-destructive evaluation (NDE) tool for thermal barrier coatings (TBC). This research is focused on NDE of electron beam physical vapor deposition (EB-PVD) TBC’s. FD-OCT is an interferometric technique, which uses spectrally broadband visible or infrared light to obtain spectrally resolved interferograms of the light that is back-scattered from subsurface structures and defects (e.g., interfaces, cracks, voids) in optically translucent material. When the Fourier transform is applied to the interferogram, a depth-resolved image of the back-scattering sites is obtained. FD-OCT is shown to be a useful NDE tool that can profile the top coat-metal substrate interface and measure the top coat thickness. Also, it has the potential of assessing microcracking and spallation damage. PLPS provides quantitative information on stress in the thermally grown oxide (TGO) by measuring the spectral shifts in the laser-induced luminescence spectra of the Cr3+ ions present in the TGO. When combined, the PLPS and FD-OCT methods can provide a set of important input parameters for the TBC remaining life predicting model. Ultimately they will collect spatially resolved data on matching spatial domains. The two optical methods are applied to thermally cycled EB-PVD TBC samples. The experimental results are compared to destructive inspection data.

Near-field thermophotovoltaic (NFTPV) devices have received much attention lately as attractive energy harvesting systems, whereby a heated thermal emitter exchanges super-Planckian near-field radiation with a photovoltaic (PV) cell to generate electricity. This work describes the use of a grating structure to enhance the power throughput of NFTPV devices, while increasing thermal efficiency by ensuring that a large portion of the radiation entering the PV cell is above the bandgap. The device is modeled as a one-dimensional high-temperature tungsten grating on a tungsten substrate that radiates photons to a room-temperature In0.18Ga0.82Sb PV cell through a vacuum gap of several tens of nanometers. Scattering theory is used along with the rigorous coupled-wave analysis to calculate the radiation exchange between the grating emitter and the PV cell. A parametric study is performed by varying the grating depth, period, and ridge width in the range that can be fabricated using available fabrication technologies. By optimizing the grating parameters, it is found that the power output can be improved by 40% while increasing the energy efficiency by 6% as compared with the case of a flat tungsten emitter. Reasons for the enhancement are investigated and found to be due to the surface plasmon polariton resonance, which shifts towards lower frequencies. This work shows a possible way of improving NFTPV and sheds light on how grating structures interact with thermal radiation at the nanoscale.

Abstract This study puts forward a metasurface design which allows the flexible tuning of the elastic wave propagation path, enabling the interrogating wave field guiding into desired monitoring regions for damage detection. As a demonstrative case study, the metasurface plate contains a rectangular array of unit cells sitting in an aluminum plate. Each unit cell is comprised of a shape memory alloy substrate and a lead stub. The controllable bandgap of such a metamaterial system can be achieved due to the stiffness change of nitinol between its martensite phase and austenite phase under a thermal load. First, a Finite Element Model (FEM) of the unit cell is constructed to calculate the band structure of the metasurface plate, demonstrating the adjustable bandgap behavior. Then, numerical modeling of the metamaterial waveguide is performed by shifting the bandgap of a specific path of the metasurface away from the excitation frequency. The modeling results demonstrate that the martensite metasurface area forms a bandgap region where guided wave energy cannot penetrate. While, the bandgap of the austenite part shifts away from the excitation frequency, opening up a transmission path for the ultrasonic waves. By delicately selecting the austenite state unit cell path, four ‘S’, ‘J’, ‘T’, ‘U’ shaped routes with a fine resolution are tailored to show a SJTU logo, demonstrating the excellent waveguiding capability and the programmable waveguide feature of this shape memory metamaterial system. The proposed tunable waveguiding methodology possesses great application potential in future Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) applications.

Abstract Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) systems generally adopt piezoelectric transducers which emit omnidirectional wave fields. The achievement of directionality of guided wave generation will benefit the structural sensing purpose, which allows better detection and localization of the damage sites. In this study, a type of metamaterial ultrasonic radar is proposed for the steerable unidirectional wave manipulation. It contains a circular array of unit cells stuck in an aluminum plate which are delicately arranged in a circular fashion. Each unit cell is composed of a shape memory alloy substrate and a lead stub. The controllable bandgap of such metamaterial system can be achieved due to the stiffness change of nitinol between its martensite phase and austenite phase under a thermal load. This research starts with a Finite Element Model (FEM) of the unit cell to compute its frequency-wavenumber domain dispersion characteristics, demonstrating the adjustable bandgap feature. Then, numerical modeling of the metamaterial radar is performed by shifting the bandgap of one sector of the metasurface away from the excitation frequency. The modeling results demonstrate that the martensite phase metasurface area forms a bandgap region where guided wave energy cannot penetrate, while the bandgap of the austenite sector shifts away from the excitation frequency, opening up a transmission path for the ultrasonic waves. By rotating the austenite sector, the metamaterial structure can work like a wave emission radar, realizing of the steerable unidirectional wave radiation with a single transducer. Such an active metasurface possesses great application potential in future SHM and NDE systems.

The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Service’s (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and ecosystem health are dependent on processes occurring in the entire watershed as well as riparian and floodplain areas; therefore, they cannot be manipulated independently of this interrelationship. Land use activities—such as timber management, landfills, grazing, confined animal feeding operations, urbanization, stream channelization, removal of riparian vegetation and gravel, and mineral and metals mining—threaten stream quality. Accordingly, the framework for this aquatic monitoring is directed towards maintaining the ecological integrity of the streams in those parks. Invertebrates are an important tool for understanding and detecting changes in ecosystem integrity, and they can be used to reflect cumulative impacts that cannot otherwise be detected through traditional water quality monitoring. The broad diversity of invertebrate species occurring in aquatic systems similarly demonstrates a broad range of responses to different environmental stressors. Benthic invertebrates are sensitive to the wide variety of impacts that influence Ozark streams. Benthic invertebrate community structure can be quantified to reflect stream integrity in several ways, including the absence of pollution sensitive taxa, dominance by a particular taxon combined with low overall taxa richness, or appreciable shifts in community composition relative to reference condition. Furthermore, changes in the diversity and community structure of benthic invertebrates are relatively simple to communicate to resource managers and the public. To assess the natural and anthropo-genic processes influencing invertebrate communities, this protocol has been designed to incorporate the spatial relationship of benthic invertebrates with their local habitat including substrate size and embeddedness, and water quality parameters (temperature, dissolved oxygen, pH, specific conductance, and turbidity). Rigid quality control and quality assurance are used to ensure maximum data integrity. Detailed standard operating procedures (SOPs) and supporting information are associated with this protocol.