Готові списки джерел за темами / Q modulator

Добірка наукової літератури з теми "Q modulator"

Автор: Grafiati
Опубліковано: 8 червня 2022
Оновлено: 9 червня 2022

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  1. Статті в журналах
  2. Дисертації
  3. Книги
  4. Частини книг
  5. Тези доповідей конференцій

Статті в журналах з теми "Q modulator":

1

Yang, Zhixian, Kun Qu, and Xiang Liu. "Frequency-Octupling Millimeter-Wave Optical Vector Signal Generation via an I/Q Modulator-Based Sagnac Loop." Symmetry 11, no. 1 (January 14, 2019): 84. http://dx.doi.org/10.3390/sym11010084.

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A new method for generating frequency-octupling millimeter-wave (mm-wave) vector signals in optical fields via a Sagnac loop is proposed. In this scheme, two orthogonally polarized fourth order sidebands can be obtained through an integrated dual-polarization quadrature phase shift keying (DP-QPSK) modulator. The two optical sidebands are sent into an I/Q modulator-based Sagnac loop. The I/Q modulator is modulated by a 16QAM baseband signal. In the Sagnac loop, one of the sidebands is modulated by the baseband vector signal along one direction, and the other sideband is unmodulated along the opposite direction because the I/Q modulator has the traveling-wave nature. Thanks to this modulation property and the symmetrical structure of the Sagnac loop, a frequency-octupling mm-wave vector signal that is free from interband beating and fiber chromatic dispersion interference can be generated by the photodetector (PD). After simulating a 20 km single-mode fiber (SMF) transmission, the generated frequency-octupling vector signal was good in function.
2

M. A. Eid, Mahmoud, Ashraf S. Seliem, Ahmed Nabih Zaki Rashed, Abd El-Naser A. Mohammed, Mohamed Yassin Ali, and Shaimaa S. Abaza. "The key management of direct/external modulation semiconductor laser response systems for relative intensity noise control." Indonesian Journal of Electrical Engineering and Computer Science 21, no. 2 (February 1, 2021): 968. http://dx.doi.org/10.11591/ijeecs.v21.i2.pp968-977.

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<p><span>This study outlines the management of either direct or external modulation semiconductor laser systems for the key solution of bit rate up to 25 Gb/s under relative intensity noise (RIN) control. The bias and modulation peak currents based laser rate equations are optimized to achieve max Q factor and min bit error rate (BER) using first proposed model and optical/electrical signal power, optical/electrical signal to noise ratio are also enhanced using second proposed model. The percentage enhancement ratio in max. Q-factor and min. BER using first proposed model ranges from 53.25 % to 71.63 % in compared to the previous model. In the same way, by using second proposed model, the electrical signal power at optical receiver is enhanced within the range of 48.66 % to 68.88 % in compared to the previous model. Optical signal/noise ratio (OSNR) after optical fiber cable (OFC), signal/noise ratio (SNR) after electrical filter are measured with using different electrical pulse generators and electrical modulators at the optimization stage. The first proposed model reported better max. Q and min. BER values than the previous model. In addition to the second proposed model (direct modulation) has outlined better optical/electrical signal power than the previous model, while max. Q, min. BER values are kept constant. It is found that non return to zero pulse generator has presented better signal power than other pulse generators by using second proposed model. As well as the mixed of raised cosine pulse generator with external modulator reported max. Q, min. BER with other pulse generators by using first proposed model. OSNR at OFC is optimized by using continuous phase frequency shift keying (CPFSK) electrical modulator, While SNR at optical receiver is optimized by using phase shift keying (PSK) electrical modulator.</span></p>
3

Cohen, D. A., M. Hossein-Zadeh, and A. F. J. Levi. "High-Q microphotonic electro-optic modulator." Solid-State Electronics 45, no. 9 (September 2001): 1577–89. http://dx.doi.org/10.1016/s0038-1101(01)00165-4.

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4

Alavi, M. S., R. B. Staszewski, L. C. N. de Vreede, A. Visweswaran, and J. R. Long. "All-Digital RF $I/Q$ Modulator." IEEE Transactions on Microwave Theory and Techniques 60, no. 11 (November 2012): 3513–26. http://dx.doi.org/10.1109/tmtt.2012.2211612.

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5

Kedia, Deepak, and Monika Nehra. "Extended Reach 10 Gb/s Transmission with an Optical I/Q Modulator Using VCSELs over OFDM-Based Multimode Fiber Link." International Journal of Optics 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/2395495.

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This paper investigates the possibilities of extending the reach of a 10 Gb/s orthogonal frequency division multiplexing- (OFDM-) based multimode fiber (MMF) link with an optical I/Q modulation technique through vertical cavity surface emitting lasers (VCSELs). The proposed I/Q modulation technique comprises two VCSELs in a 90° hybrid combination to produce I/Q modulated OFDM signal. The results show the excellent performance (in terms of BER and Q factor) of the direct-detection optical- (DDO-) OFDM system with the proposed I/Q modulation in comparison to the direct modulation case. The proposed system is able to achieve worst-case BER of about 1.8616 × 10−3 and Q factor of about 10.9949 dB over a 5 km MMF link. The I/Q modulation technique in the DDO-OFDM system has further been investigated for extending the transmission reach of the MMF link using multispan configuration.
6

Hayrapetyan, Yegisabet Hakob, and Stepan Karen Petrosyan. "Construction Features of The High-Precision Laser Rangefinder Light Modulator." Journal of Architectural and Engineering Research 1, no. 1 (June 25, 2021): 26–31. http://dx.doi.org/10.54338/27382656-2021.1-5.

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The issues related to the development of a light modulator operating on the electro-optical effect of laser rangefinders by the modulation method are considered. To reduce the modulation power, it is proposed to lower the modulation frequency to 750-800 MHz, while simultaneously increasing the modulation quality to Q = 1000. The study of the phase determination error of a high-precision laser rangefinder depending on temperature showed that it is rational to construct the light modulator by radial installation of the KDP electro-optical crystal, with separated modulation and demodulation channels, while on combined resonators.
7

Sorger, Volker J., Norberto D. Lanzillotti-Kimura, Ren-Min Ma, and Xiang Zhang. "Ultra-compact silicon nanophotonic modulator with broadband response." Nanophotonics 1, no. 1 (July 1, 2012): 17–22. http://dx.doi.org/10.1515/nanoph-2012-0009.

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AbstractElectro-optic modulators have been identified as the key drivers for optical communication and signal processing. With an ongoing miniaturization of photonic circuitries, an outstanding aim is to demonstrate an on-chip, ultra-compact, electro-optic modulator without sacrificing bandwidth and modulation strength. While silicon-based electro-optic modulators have been demonstrated, they require large device footprints of the order of millimeters as a result of weak non-linear electro-optical properties. The modulation strength can be increased by deploying a high-Q resonator, however with the trade-off of significantly sacrificing bandwidth. Furthermore, design challenges and temperature tuning limit the deployment of such resonance-based modulators. Recently, novel materials like graphene have been investigated for electro-optic modulation applications with a 0.1 dB per micrometer modulation strength, while showing an improvement over pure silicon devices, this design still requires device lengths of tens of micrometers due to the inefficient overlap between the thin graphene layer, and the optical mode of the silicon waveguide. Here we experimentally demonstrate an ultra-compact, silicon-based, electro-optic modulator with a record-high 1 dB per micrometer extinction ratio over a wide bandwidth range of 1 μm in ambient conditions. The device is based on a plasmonic metal-oxide-semiconductor (MOS) waveguide, which efficiently concentrates the optical modes’ electric field into a nanometer thin region comprised of an absorption coefficient-tuneable indium-tin-oxide (ITO) layer. The modulation mechanism originates from electrically changing the free carrier concentration of the ITO layer which dramatically increases the loss of this MOS mode. The seamless integration of such a strong optical beam modulation into an existing silicon-on-insulator platform bears significant potential towards broadband, compact and efficient communication links and circuits.
8

Wang, Dong-Fei, Li-Ting Shan, and Lei Wang. "Photonic Filter-Free Scheme for D-Band mm-Wave Signal Generation with Frequency 12-Tupling Only via One Integrated In-Phase and Quadrature Modulator." Journal of Nanoelectronics and Optoelectronics 17, no. 1 (January 1, 2022): 40–47. http://dx.doi.org/10.1166/jno.2022.3167.

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In this work, we have proposed a new scheme of generating continuously tunable and filter-less D-band millimeter-wave (mm-wave) signal with frequency 12-tupling only via one integrated in-phase and quadrature (I/Q) modulator. The two sub-MZMs in the I/Q modulator, biased at peak point, are applied to eliminate odd order optical tones. By controlling the phase and amplitude of RF driving signals, I/Q modulator bias point, and the optical phase shifter embed in the lower arm of I/Q modulator, a frequency 12-tupling signal can be obtained through the beat frequency in the photodetector. Employing 10 GHz RF drive signal, 120 GHz millimeter wave signal can be realized by detailed mathematical formula derivation and simulation, and optical sideband suppression ratio (OSSR) can reach 37.65 dB and radio frequency sideband suppression ratio (RFSSR) can reach 32.08 dB.
9

Nehra, Monika, and Deepak Kedia. "Design of Optical I/Q Modulator Using Dual-drive Mach-Zehnder Modulators in Coherent Optical-OFDM System." Journal of Optical Communications 39, no. 2 (April 25, 2018): 155–59. http://dx.doi.org/10.1515/joc-2016-0089.

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AbstractA CO-OFDM system combines the advantages of both coherent detection and OFDM modulation for future high speed fiber transmission. In this paper, we propose an I/Q modulation technique using dual-drive MZMs for high rate 10 Gb/s CO-OFDM system. The proposed modulator provides 10.63 dBm improved optical spectra compared to a single dual-drive MZM. The simulation results in terms of BER and Q factor are quite satisfactory upto a transmission reach of 3,000 km and that to without making use of any dispersion compensation. A BER of about 8.03×10−10and 15.06 dB Q factor have been achieved at −10.43 dBm received optical power.
10

Blas, J. M., and J. I. Alonso. "Low cost wideband I-Q vector modulator." Electronics Letters 33, no. 1 (1997): 18. http://dx.doi.org/10.1049/el:19970031.

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Статті в журналах Дисертації

Дисертації з теми "Q modulator":

1

Unlu, Ozkaya Ayse. "Design And Implementation Of A Broadband I-q Vector Modulator And A Feedforward Linearizer For V/uhf Band." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611565/index.pdf.

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Considering the requirements of the commercial and military applications on amplitude and phase linearity, it is necessary to reduce nonlinearity of the amplifiers. There are several linearization techniques that are used to reduce nonlinearity effects. Feedforward linearization technique is known as one of the best linearization methods due to its superior linearization performance and broadband operation. Vector modulators which allows amplitude and phase modulation simultaneously, is the most important component of a feedforward system. In this thesis, first of all a broadband V/UHF vector modulator designed and implemented. Then a feedforward system is investigated and implemented using the designed vector modulator for V/UHF band.
2

Abdi, Abyaneh Mohammad. "Génération des signaux agrégés en fréquences dans le contexte de LTE-A." Thesis, Paris, ENST, 2016. https://pastel.archives-ouvertes.fr/tel-03689710.

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Dans ce travail de thèse, on a proposé une structure de génération des signaux multi-porteuse afin de créer plusieurs oscillateurs locaux (OL ) tout en utilisant qu’un modulateur I/Q. Ces signaux peuvent être utilisés dans les récepteurs de LTE-A pour la transposition des signaux agrégé en fréquence vers la bande de base. On développe la structure afin de l’utiliser en émetteur répondant aux normes du standard LTE-A. La nouvelle structure nous permet de générer n signaux agrégés en fréquences, de manière simultanée, par une seule chaîne de transmission (c.a.d un modulateur I/Q, un OL). En utilisant cette structure on réduit le nombre de circuits utilisés, en comparaison du cas où n signaux agrégés en fréquences sont générés par n émetteurs. La fréquence d’échantillonnage est réduite dans notre cas par rapport au cas où les signaux sont générés directement de la bande de base à la bande RF avec des convertisseurs analogiques numériques adéquats. Dans la troisième partie, on se concentre sur les imperfections et les non linéarités du modulateur I/Q dans le cadre de notre structure multibande. On modélise le fonctionnement du modulateur multi-bande en utilisant les échantillons en entrée et en sortie. Notre modèle est dérivé de la série de Volterra qui prends en compte les effets non linéaires et les effets mémoires ainsi que les imperfections du modulateur I/Q. Puis, on obtient la fonction "inverse" du modèle et on l’applique à l’entrée du modulateur afin de corriger et linéariser la sortie du modulateur I/Q. La fonction "inverse" est appelée DPD (en anglais : Digital Pre-Distortion). Enfin, on a évalué le modèle et la DPD en simulations et en mesures
In this dissertation, a signal generation structure is proposed using which a multitone Local Oscillator (LO) signal is created by a single I/Q modulator. These LOs can be used in the CA receivers to down-convert the transmitted component carriers simultaneously. The multi-tone LO signal structure is further developed to be used at the transmitter as a CA generation solution. Using the proposed structure n-component carriers can be generated in parallel. This structures requires lower sampling rates with respect to the case where RF signals are synthesized directly by digital-to- analog converters. Moreover, less circuitry is required, because one single I/Q modulator is used to generate n component carriers, instead of n I/Q modulators. This work follows on investigating the origin of impairments and mild nonlinearities in our I/Q modulator. To overcome these problems, we focus on the functionality of the overall system rather than each component of the I/Q modulator. This method is called behavioral modeling. Once the nonlinear model is obtained, if its inverse function is applied to the input, a linearized output is expected. The generation of the inverse function is called Digital Pre-Distortion (DPD). We propose a tri-band behavioral model for nonlinearities and impairments in tri-band CA using our I/Q modulator. Furthermore, the DPD of the model is evaluated in simulations and experiments
3

Mayer, Sebastian. "Hilbert modular forms for the fields Q([square root]5), Q([square root]13) and Q([square root]17)." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985767022.

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4

McCorkindale, Jane. "The 2-modular representation theory of PSU←3(q), q #ident to# 3(mod 4)." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279980.

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5

Kassaei, Payman L. 1973. "p-adic modular forms over Shimura curves over Q." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85304.

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6

Malmström, Mikael. "All-fiber modulators for laser applications." Doctoral thesis, KTH, Laserfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105863.

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The objective of this thesis was to explore the usefulness of all-fiber modulators for laser applications. The modulators were all based on refractive index change achieved in the core of the studied fiber- components, exploiting either the elasto-optic effect or the electro-optic effect. This was realized with the aid of electrodes inside the fiber cladding close to the core that provided either thermal stress in the core, or an electric field across the core. The electrodes consisted of low melting-point alloys, such as BiSn and AuSn, which were pushed into the hole-fiber, in the liquid state, which then solidified to form solid electrodes filling the entire hole. Together with an analyzer such as a polarizer or an interferometer the achieved refractive index modulation in the core could then be translated into an amplitude modulation of the guided light, which was subsequently utilized for switching fiber-lasers to generate cavity dumped, Q-switched, or mode-locked pulses. The fast rise/fall-time of a few nanoseconds for the elasto-optic devices was due to the fast thermal expansion of the electrodes. The maximum repetition rate, however, was limited to a few tens of kHz, due to the slow thermal processes for dissipation of the applied energy. The electro-optic fiber components, which displayed similar rise/fall-times on the other hand, showed a much higher cut-off frequency of 16 MHz. The electro-optic, all-fiber switch was also employed to select single pulses at 1 MHz repetition rate out of a 7 MHz train of pulses. Additionally, simulations using the finite element method were performed in order to gain insight and to explain the underlying processes of the observed response of a long-period grating written in a 2-hole fiber with electrodes, when applying HV-pulses to one of these. The thesis shows that the studied fiber-components show great potential of becoming complementary devices with high damage threshold for all-fiber laser applications in the future.

QC 20121129

7

Sabra, Mostafa. "Développement de lasers à fibres thulium bi-fréquences à impulsions synchrones pour la réalisation de sources Térahertz." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0118.

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Dans le cadre d’un projet collaboratif entre le laboratoire XLIM (UMR 7252 du CNRS et de l'Université de Limoges) et le laboratoire de recherche IPHT situé à Jena en Allemagne, mon projet de thèse consiste à développer un laser à fibre dopée thulium bi-fréquences largement accordable à impulsions synchrones pour la réalisation d’une source Térahertz puissante et accordable. Basé sur l’utilisation de deux réseaux de Bragg en volume (VBGs) et d’une fibre dopée thulium à double gaine et à maintien de polarisation (diamètre de coeur = 20 μm) fabriquée par la méthode REPUSIL, un laser mono-fréquence et bi-fréquences largement accordable a été réalisé et étudié en régime continu. Une accordabilité de 1nm à 144 nm a été obtenue avec une puissance supérieure à 4,5 W et un bon contraste signal sur bruit (~45 dB) et une largeur spectrale inférieure à 0,1 nm. En régime déclenché, un modulateur acousto-optique (AOM) a été utilisée en espace libre dans la cavité laser afin de générer les impulsions. La fibre à double gaine a été remplacée par une fibre dopée thulium à large coeur (40 μm) appelée FA-LPF pour repousser le seuil d’apparition des effets non-linéaires et travailler avec une fibre courte pour diminuer la durée d’impulsion et augmenter la puissance crête des impulsions obtenues. Une source déclenchée bi-fréquences largement accordable (de 3,8 nm jusqu’à 120nm) a été développée avec une puissance crête supérieure à 8 kW et une durée d’impulsion autour de 26 ns obtenues indépendamment de la valeur de Δλ pour une fréquence de répétition de 1 kHz. Un contraste supérieur à 20 dB a été obtenu limité par les pics parasites générés par le FWM pour les valeurs de Δλ inférieures à 45 nm. La largeur spectrale des raies lasers mesurée à 3 dB du maximum a été inférieure à 0,3 nm
As part of a collaborative project between the XLIM laboratory (UMR 7252 of the CNRS and the University of Limoges) and the IPHT research laboratory located in Jena, Germany, my thesis project consists in the development of a widely tunable dual-wavelength synchronous pulsed thulium doped fiber laser for the realization of an efficient and tunable terahertz source. Based on the use of two volume Bragg gratings (VBGs) and a double-clad, polarization-maintaining thulium doped fiber (core diameter = 20 μm) manufactured by the REPUSIL method, a widely tunable single-wavelength laser and dual-wavelength laser has been realized and studied in continuous regime. A tunability of 1 nm to 144 nm was obtained with a power more than 4.5 W and a good signal-to-noise contrast (~ 45 dB) and a spectral linewidth less than 0.1 nm. In pulse regime, an acousto-optic modulator (AOM) was used in free space in the laser cavity to generate the pulses. The double-clad fiber has been replaced by a large-core thulium doped fiber (40 μm) called FA-LPF to to fend off the threshold of non-linear effects and work with a short fiber to decrease the pulse duration and increase the peak power of the obtained pulses. A widely tunable (from 3.8 nm to 120 nm) Q-switched dual-wavelength synchronous-pulsed thulium-doped fiber laser was developed with a peak power more than 8 kW and a pulse duration around 26 ns obtained independently of the value of Δλ at 1 kHz of repetition rate. A contrast higher than 20 dB was obtained limited by the FWM peaks generated for Δλ values below 45 nm. The spectral linewidth of the laser measured at 3 dB of the maximum was less than 0.3 nm
8

Preece, Daryl. "Novel uses of spatial light modulators in optical tweezers." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2619/.

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In recent years spatial light modulators (SLMs) have become an integral part of many optical trapping experiments. Yet their usefulness, which stems from their flexibility, is often under exploited. In this thesis I seek to demonstrate how it is possible to expand the range of optical trapping applications that may benefit from the use of spatial light modulators. From exploring the benefits of increased resolution to demonstrating novel applications like position clamping and polarization control, I show how SLMs are a resource which can benefit optical trapping in new and unconventional ways. The optical properties of liquid crystals have long been known however it is only recently that they have been applied to optical tweezers. The physics and operation of spatial light modulators are discussed in chapter 1, with specific attention paid to those aspects of operation which are of pertinent practical use to optical trapping. In chapter 2 it is shown how phase only modulation can be used to create effective holographic optical tweezers systems which are capable of manipulating micron scale particles and measuring pico-Newton forces. Chapter 3 charts the development and characterization of a 4 Mega-pixel spatial light modulator which was created as an improvement on current SLM technology. The role of SLMs in utilising lights angular momentum as a tool for creating rotational torque is discussed in chapter 4. In chapter 5 describes how SLMs can be used to create torques based the application of spin angular momentum to birefringent particles. We show, in chapter 6 how with suitable software engineering it is possible to both move optical traps and track particles in real time. Since the use of SLMs has been previously been limited by their bandwidth constraints we discuss in chapter 7 the use spatial light modulators in closed loop systems. We finish with a discussion of the use of SLMs in a new technique that may be applied to microrheology.
9

Hart, Jaynee E. "Biochemical and genetic approaches to modulate phototropin photoreceptor sensitivity." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30991/.

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The necessity of light for plants to sustain their autotrophic lifestyle has made the optimization of growth to maximize light capture a crucial strategy for survival in light-limiting environments. Increases in light capture can be achieved through alterations in plant architecture, such as modifications to leaf position and stem length. Responses to the light environment are mediated by a network of photoreceptor proteins, which sense specific wavelengths of light and respond to light excitation by initiating signaling. Higher plants respond to red and far-red light through the phytochrome family, blue light through cryptochromes, the zeitlupe family, and phototropins, and UV-B light through the UV RESISTANCE LOCUS 8 photoreceptor. Of these photoreceptor proteins, the phototropins (phots) are perhaps the most closely tied to photosynthetic efficiency. Higher plant phots, phot1 and phot2, mediate leaf expansion to maximize the surface area available for light capture as well as control movement and positioning responses, such as petiole inclination, movement towards more favorable light conditions through phototropism, and, at a cellular level, chloroplast movement. Furthering the role of phots in optimizing responses upstream of photosynthesis, phot1 and phot2 also control stomatal opening in response to blue light, allowing the uptake of carbon dioxide into the leaf for fixation into sugars. In general, these responses are redundantly coordinated by both phot1 and phot2, with phot1 acting as the primary sensor due to its greater sensitivity. Because of the profound effect phots have on photosynthetic competence, the studies presented here examine phot1 with the goal of understanding the physiological role of phot1 sensitivity in plants and explore the possibility that enhancing phot1 sensitivity could increase plant growth. Phots consist of two N-terminal light sensing LOV (Light, Oxygen or Voltage) domains, LOV1 and LOV2, coupled to a serine/threonine kinase domain at the C-terminus. Each of the LOV domains bind a flavin mononucleotide (FMN) chromophore that allows these domains to perceive blue light. In darkness, FMN is non-covalently bound within each of the LOV domains, which repress the activity of the kinase domain. When FMN is excited by blue light, a covalent bond is formed between a conserved cysteine residue present within each LOV domain and FMN. LOV2 specifically is coupled to the kinase domain through two alpha helices, Jα and A’α, which become disordered following the formation of the covalent photoadduct. The unfolding of these alpha helices relieves repression of the kinase domain, initiating signaling. The onset of phot1 signaling is characterized by phot1 autophosphorylation and the dephosphorylation of the phot1 signaling partner NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3). Over time, the covalent photoadduct decays and phot1 returns to its inactive dark state, completing the photocycle. The chemistry of the phot1 photocycle in vitro is understood in detail, but its downstream signaling following activation remains relatively elusive, with only a handful of signaling partners and phosphorylation substrates identified. For the sensitivity of phot1 to be thoroughly explored, how the phot1 photocycle affects plant growth as well as how phot1 activity is modulated by signaling partners needed to be addressed. Therefore, a biochemical approach was used to introduce mutations within LOV2 to slow its dark reversion to prolong signaling and investigate how this modulates phot1 sensitivity in vitro and in planta, and, secondly, a genetic strategy was employed to uncover whether any signaling processes can modulate phot1 sensitivity in plants. Compared to other photoreceptors that receive blue light through LOV domains, dark reversion of phot1 following a light stimulus is relatively fast, with the lit state lasting only approximately 15 minutes, while other LOV domains remain activated for many hours. To generate slow photocycle mutants of phot1, previous characterizations of slow photocycling LOV domains were exploited to engineer the phot1 photocycle to have a slower dark reversion by introducing mutations into LOV2. To study the photocycle in vitro, the phot1 light-sensing module consisting of the LOV1 and LOV2 domains (LOV1+LOV2) was heterologously expressed and purified from E. coli and the photocycle was measured spectrophotometrically. Using this approach, 13 LOV2 variants were generated and examined to identify slow photocycle mutants. Three mutations in LOV2, N476L, V478I, and L558I, were found to slow the LOV1+LOV2 photocycle in vitro. Following identification, these mutations were introduced into full-length phot1 expressed heterologously in insect cells to verify the autophosphorylation activity of each mutant. Following the characterization of the candidate slow photocycle mutants in vitro, each phot1 photocycle mutant was examined in planta in a phot1phot2 double mutant background to see whether possession of a slow photocycle increased phot1 sensitivity. Of the three candidate mutations, V478I and L558I were verified as possessing a slow dark reversion through the phosphorylation status of NPH3. NPH3 is dephosphorylated in a phot1-dependent manner following light treatment; it was found that in the presence of wild-type phot1, the phosphorylated form of NPH3 is recovered around one hour following a return to darkness after phot1 stimulation by blue light. By contrast, the dephosphorylated state of NPH3 was sustained in phot1-V478I and -L558I for a substantially longer period of time, consistent with a slow phot1 photocycle and prolonged phot1 activation in these mutants. Surprisingly, it was found that these mutants were less sensitive than wild-type phot1 for phototropism in response to low intensity light treatments. Furthermore, biomass accumulation was not increased in the phot1-L558I mutant under growth conditions consisting of very low light. While the photocycle mutants did not exhibit increased sensitivity or growth in response to continuous light treatments, evidence from collaborators indicated that phot1-L558I is more efficient than wild-type phot1 for the chloroplast accumulation response following brief pulses of blue light. While the role of the phot1 photocycle under continuous irradiation remained unclear, this enhanced chloroplast accumulation response implies that the phot1 photocycle is important for its sensitivity to brief irradiations. Unlike phot1, further work with phot2 later indicated that introducing a slow photocycle mutation to phot2 LOV2 can significantly increase growth in a phot1phot2 mutant background under continuous low light. To investigate other factors that may affect phot1 sensitivity, a genetic screen was undertaken in an attempt to identify suppressors of phot1 activity. The LOV2Kinase (L2K) transgenic line, which expresses a truncated version of phot1 in a phot1phot2 double mutant background, was previously found to be unable to respond to low-intensity blue light, though it can mediate phot1 responses when the light intensity is increased. Because L2K possesses this conditional phenotype, random mutations were introduced into the genome of L2K-expressing plants and a screen was established to identify mutants that were able to respond to low-intensity light with the hypothesis that those mutations could lie within suppressors of phot1 activity, allowing L2K to signal under circumstances where it ordinarily could not. Using this approach, three independent candidate suppressor mutants were identified that had increased sensitivity for the petiole positioning response under low light. One suppressor mutant was identified as a novel allele of the phytochrome B red light receptor, the second is likely to be a mutant of a transcription factor, and the identity of the third candidate suppressor is still not known, though it overexpressed the L2K protein. These candidate suppressors may represent novel modulators of phot1 activity and possible mechanisms for how these candidate suppressors may act on phot1 activity are discussed. In summary, both the biochemical and genetic approaches yielded mutants with increased sensitivity for phot1-mediated responses, enabling a more detailed understanding of how phot1 sensitivity influences its activity and plant growth.
This lays the groundwork for extending the increased sensitivity observed in response to pulses in the photocycle mutants to responses other phot1-mediated responses, and for integrating new models of suppression of phot1 activity into our framework for phot1 activation and signaling.
10

Dembélé, Lassina. "Explicit computations of Hilbert modular forms on Q(square root 5)." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38477.

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Анотація:
We compute the eigenvalues of the first few Hecke operators Tp (N( p ) ≤ 100) for all Hilbert modular forms on Q5 of parallel weight 2 and level of norm less than 500. This is done by exploiting the Jacquet-Langlands correspondence which allows us to transfer such computations to forms on the (totally definite) Hamilton quaternion algebra over Q5 . We use these computations to test numerically a conjecture of Oda on periods of Hilbert modular forms.
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Книги з теми "Q modulator":

1

Ono, Ken. The web of modularity: Arithmetic of the coefficients of modular forms and q-series. Providence, R.I: American Mathematical Society, 2004.

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2

Alladi, Krishnaswami. Partitions, q-Series, and Modular Forms. New York, NY: Springer Science+Business Media, LLC, 2012.

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3

Alladi, Krishnaswami, and Frank Garvan, eds. Partitions, q-Series, and Modular Forms. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-0028-8.

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4

Andrews, George E., and Frank Garvan, eds. Analytic Number Theory, Modular Forms and q-Hypergeometric Series. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-68376-8.

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5

Kleshchëv, A. S. Modular branching rules for projective representations of symmetric groups and lowering operators for the supergroup Q(n). Providence, Rhode Island: American Mathematical Society, 2012.

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6

Chamizo, Fernando. Trends in number theory: Fifth Spanish meeting on number theory, July 8-12, 2013, Universidad de Sevilla, Sevilla, Spain. Providence, Rhode Island: American Mathematical Society, 2015.

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Ono, Ken. The Web of Modularity: Arithmetic of the Coefficients of Modular Forms and Q-Series (Cbms Regional Conference Series in Mathematics) (Cbms Regional Conference Series in Mathematics). American Mathematical Society, 2003.

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8

Andrews, George E., and Frank Garvan. Analytic Number Theory, Modular Forms and q-Hypergeometric Series: In Honor of Krishna Alladi's 60th Birthday, University of Florida, Gainesville, ... in Mathematics & Statistics ). Springer, 2019.

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9

Analytic Number Theory, Modular Forms and q-Hypergeometric Series: In Honor of Krishna Alladi's 60th Birthday, University of Florida, Gainesville, ... Proceedings in Mathematics & Statistics). Springer, 2018.

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Частини книг з теми "Q modulator":

1

Hirschhorn, Michael D. "Two Modular Equations." In The Power of q, 175–78. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57762-3_20.

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2

Gamkrelidze, R. V. "Modular Curves Over Q." In Encyclopaedia of Mathematical Sciences, 123–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-58227-1_5.

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3

Hirschhorn, Michael D. "Some Modular Equations of Ramanujan." In The Power of q, 365–71. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57762-3_40.

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4

de Gosson, Maurice A. "The Modulation Spaces $$M_s^q$$." In Symplectic Methods in Harmonic Analysis and in Mathematical Physics, 275–90. Basel: Springer Basel, 2011. http://dx.doi.org/10.1007/978-3-7643-9992-4_17.

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5

Pitale, Ameya. "Local Representation Theory of $$\mathrm{GSp}_4({\mathbb Q}_p)$$." In Siegel Modular Forms, 49–62. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15675-6_7.

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6

Andrews, George E., and Peter Paule. "MacMahon’s Dream." In Partitions, q-Series, and Modular Forms, 1–12. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0028-8_1.

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7

Ito, Masahiko, and Soichi Okada. "An Application of Cauchy–Sylvester’s Theorem on Compound Determinants to a BC n -Type Jackson Integral." In Partitions, q-Series, and Modular Forms, 145–57. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0028-8_10.

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8

Kajihara, Yasushi. "Multiple Generalizations of q-Series Identities and Related Formulas." In Partitions, q-Series, and Modular Forms, 159–80. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0028-8_11.

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9

Milne, Stephen C., and John W. Newcomb. "Nonterminating q-Whipple Transformations for Basic Hypergeometric Series in U(n)." In Partitions, q-Series, and Modular Forms, 181–224. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0028-8_12.

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10

Berndt, Bruce C., Chadwick Gugg, and Sun Kim. "Ramanujan’s Elementary Method in Partition Congruences." In Partitions, q-Series, and Modular Forms, 13–21. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0028-8_2.

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Тези доповідей конференцій з теми "Q modulator":

1

Luo, Fei, and T. Yeh. "LPFG modulator for fiber laser Q switching." In SPIE LASE: Lasers and Applications in Science and Engineering, edited by Denis V. Gapontsev, Dahv A. Kliner, Jay W. Dawson, and Kanishka Tankala. SPIE, 2009. http://dx.doi.org/10.1117/12.809797.

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2

Chandonnet, Alain, Gilles Larose, and Yves Painchaud. "All-fiber intensity modulator for Q switching." In Optics Quebec, edited by Michel Piche and Paul W. Pace. SPIE, 1994. http://dx.doi.org/10.1117/12.165622.

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3

Sohn, Donggyu B., JunHwan Kim, and Gaurav Bahl. "Ultrahigh-Q silica-ALN hybrid disk optomechanical modulator." In 2017 IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2017. http://dx.doi.org/10.1109/memsys.2017.7863401.

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4

Shen, Yiyu, Michael Polushkin, Mohammadreza Mehrpoo, Mohsen Hashemi, Earl McCune, Morteza S. Alavi, and Leo C. N. de Vreede. "A wideband I/Q RFD AC-based phase modulator." In 2018 IEEE 18th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF). IEEE, 2018. http://dx.doi.org/10.1109/sirf.2018.8304215.

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5

Boulanger, Cyrille, Luc Lapierre, and Francis Gizard. "New Cold FET I-Q Linear Vector Modulator Topology." In 2000 30th European Microwave Conference. IEEE, 2000. http://dx.doi.org/10.1109/euma.2000.338686.

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6

Jiang, Hui, Tao Shao, Cheng Zhang, Wenfeng Li, Ping Yan, and Edl Schamiloglu. "Study on Q-V Lissajous figures in nanosecond-pulsed surface discharge." In 2012 IEEE International Power Modulator and High Voltage Conference (IPMHVC). IEEE, 2012. http://dx.doi.org/10.1109/ipmhvc.2012.6518800.

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7

Buckel, T., P. Preyler, E. Hager, T. Mayer, S. Tertinek, A. Springer, and R. Weigel. "A Novel Hybrid Polar-I/Q Modulation Method relaxing RF Phase Modulator Design Requirements." In 2018 14th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME). IEEE, 2018. http://dx.doi.org/10.1109/prime.2018.8430325.

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8

Iverson, Eric W., and Milton Feng. "A 0.05-26 GHz Direct Conversion I/Q Modulator MMIC." In 2014 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS). IEEE, 2014. http://dx.doi.org/10.1109/csics.2014.6978527.

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9

Lynch, J., F. A. Traut, K. Benson, and R. Tshudy. "An mHEMT Q-Band Integrated LNA and Vector Modulator MMIC." In 2010 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS). IEEE, 2010. http://dx.doi.org/10.1109/csics.2010.5619652.

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10

Lin, Y. Y., S. T. Lin, G. W. Chang, A. C. Chiang, Y. H. Chen, and Y. C. Huang. "Electro-optic PPLN Bragg Modulator as a Laser Q-switch." In 2007 Conference on Lasers and Electro-Optics - Pacific Rim. IEEE, 2007. http://dx.doi.org/10.1109/cleopr.2007.4391516.

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