Artículos de revistas: "Size spectra"

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Mandich, M. L. "SPECTROSCOPY OF SIZE-SELECTED SEMICONDUCTOR CLUSTERS: BULK LIKE SPECTRA SEEN IN “MOLECULAR SIZE” CLUSTERS". International Journal of Modern Physics B 06, n.º 23n24 (diciembre de 1992): 3747–56. http://dx.doi.org/10.1142/s0217979292001808.

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Absorption spectra have been obtained for size selected, gas phase neutral semiconductor clusters using resonant one- and two-color photodissociation spectroscopy. We now have spectra for indium phosphide clusters containing up to 14 atoms and for silicon clusters containing up to 70 atoms. These spectra show unexpected similarities between the optical signatures of minute semiconductor clusters and their corresponding bulk forms. Equally unexpected is the spectral regularity that we observe with size for silicon clusters, which challenges all existing theories about their geometric and electronic structures.

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Wheeland, Laura J. y George A. Rose. "Acoustic measures of lake community size spectra". Canadian Journal of Fisheries and Aquatic Sciences 73, n.º 4 (abril de 2016): 557–64. http://dx.doi.org/10.1139/cjfas-2014-0446.

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Acoustic methods were tested as an alternative to catch data to measure size spectra of freshwater fish communities in Lac du Bonnet (LdB), Manitoba, Canada. Eleven daytime hydroacoustic surveys conducted in 2011 and 2012 enabled length-frequency spectra of fish communities to be calculated within LdB. Fish echoes tracked and converted to length (>5 cm) formed size spectra with significant linear regressions in all cases (p values < 0.05, R2 values from 0.87 to 0.99). Fish abundance (spectral height) was greater in 2011 (mean ± SD = 0.19 ± 0.15) than in 2012 (–0.19 ± 0.20), decreasing through the summer sampling season. Both abundance and size composition (spectral slope) of fish communities differed between three basins of varying bathymetry, with steepest slopes and lowest heights associated with the shallowest waters. We conclude that acoustically derived size spectra provide an efficient means to detect and monitor fish community dynamics over varied spatial and temporal scales in aquatic ecosystems where fish are not highly aggregated and hence single acoustic targets predominate.

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Zhou, Peng, Wei Yang, Minzan Li y Weichao Wang. "A New Coupled Elimination Method of Soil Moisture and Particle Size Interferences on Predicting Soil Total Nitrogen Concentration through Discrete NIR Spectral Band Data". Remote Sensing 13, n.º 4 (19 de febrero de 2021): 762. http://dx.doi.org/10.3390/rs13040762.

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Rapid and accurate measurement of high-resolution soil total nitrogen (TN) information can promote variable rate fertilization, protect the environment, and ensure crop yields. Many scholars focus on exploring the rapid TN detection methods and corresponding soil sensors based on spectral technology. However, soil spectra are easily disturbed by many factors, especially soil moisture and particle size. Real-time elimination of the interferences of these factors is necessary to improve the accuracy and efficiency of measuring TN concentration in farmlands. Although, many methods can be used to eliminate soil moisture and particle size effects on the estimation of soil parameters using continuum spectra. However, the discrete NIR spectral band data can be completely different in the band attribution with continuum spectra, that is, it does not have continuity in the sense of spectra. Thus, relevant elimination methods of soil moisture and particle size effects on continuum spectra do not apply to the discrete NIR spectral band data. To solve this problem, in this study, moisture absorption correction index (MACI) and particle size correction index (PSCI) methods were proposed to eliminate the interferences of soil moisture and particle size, respectively. Soil moisture interference was decreased by normalizing the original spectral band data into standard spectral band data, on the basis of the strong soil moisture absorption band at 1450 nm. For the PSCI method, characteristic bands of soil particle size were identified to be 1361 and 1870 nm firstly. Next, normalized index Np, which calculated wavelengths of 1631 and 1870 nm, was proposed to eliminate soil particle size interference on discrete NIR spectral band data. Finally, a new coupled elimination method of soil moisture and particle size interferences on predicting TN concentration through discrete NIR spectral band data was proposed and evaluated. The six discrete spectral bands (1070, 1130, 1245, 1375, 1550, and 1680 nm) used in the on-the-go detector of TN concentration were selected to verify the new method. Field tests showed that the new coupled method had good effects on eliminating interferences of soil moisture and soil particle size.

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Moisseev, Dmitri N. y V. Chandrasekar. "Nonparametric Estimation of Raindrop Size Distributions from Dual-Polarization Radar Spectral Observations". Journal of Atmospheric and Oceanic Technology 24, n.º 6 (junio de 2007): 1008–18. http://dx.doi.org/10.1175/jtech2024.1.

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This paper presents a method to retrieve raindrop size distributions (DSD) from slant profile dual-polarization Doppler spectra observations. It is shown that using radar measurements taken at a high elevation angle raindrop size distributions can be retrieved without making an assumption on the form of a DSD. In this paper it is shown that drop size distributions can be retrieved from Doppler power spectra by compensating for the effect of spectrum broadening and mean velocity shift. To accomplish that, spectrum deconvolution is used where the spectral broadening kernel width and wind velocity are estimated from spectral differential reflectivity measurements. Since convolution kernel is estimated from dual-polarization Doppler spectra observations and does not require observation of a clear-air signal, this method can be used by most radars capable of dual-polarization spectra measurements. To validate the technique, sensitivity of this method to the underlying assumptions and calibration errors is evaluated on realistic simulations of radar observations. Furthermore, performance of the method is illustrated on Colorado State University–University of Chicago–Illinois State Water Survey radar (CSU–CHILL) measurements of stratiform precipitation.

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Lo, Su-Chin y Chris W. Brown. "Infrared Spectral Search for Mixtures in Medium-Size Libraries". Applied Spectroscopy 45, n.º 10 (diciembre de 1991): 1621–27. http://dx.doi.org/10.1366/0003702914335256.

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A new algorithm is presented for searching medium-size infrared spectral libraries for the components in spectra of mixtures. The algorithm treats the spectra in the library as an m-component quantitative analysis problem in which each of the library spectra represents a standard mixture having a concentration of 1.0 for that component. Principal component regression (PCR) is used to reduce the dimensionality of the problem and to provide the regression coefficients for determining pseudo-concentrations or composition indices (CI) in mixtures. The PCR analysis is followed by the application of an adaptive filter to remove all similarity of the first target component from the mixture and from a selected subgroup of the library. This is followed by a second PCR analysis on the modified spectral data to identify the next target compound. If the correct target components are selected with successive applications of the adaptive filter, the residuals will approach zero. All components in five two- and three-component mixtures were correctly identified by this new Mix-Match algorithm, whereas only two of the five mixtures were completely identified by a typical dot-product search routine.

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Hamilton, Victoria E., Christopher W. Haberle y Thomas G. Mayerhöfer. "Effects of small crystallite size on the thermal infrared (vibrational) spectra of minerals". American Mineralogist 105, n.º 11 (1 de noviembre de 2020): 1756–60. http://dx.doi.org/10.2138/am-2020-7602.

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Abstract The thermal infrared (TIR, or vibrational) emission spectra of a suite of synthetic Mg-Fe olivines exhibit notable differences from their natural igneous counterparts in terms of their band shapes, relative depths, and reduced shifts in some band positions with Mg-Fe solid solution. Comparable reflectance spectra acquired from olivine-dominated matrices and fusion crusts of some carbonaceous chondrite meteorites exhibit similar deviations. Here we show that these unusual spectral characteristics are consistent with crystallite sizes much smaller than the resolution limit of infrared light. We hypothesize that these small crystallites denote abbreviated crystal growth and also may be linked to the size of nucleation sites. Other silicates and non-silicates, such as carbonates, exhibit similar spectral behaviors. Because the spectra of mineral separates are commonly used in the modeling and analysis of comparable bulk rock, meteorite, and remote sensing data, understanding these spectral variations is important to correctly identifying the minerals and interpreting the origin and/or secondary processing histories of natural materials.

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Camacho, J. y R. V. Solé. "Scaling in ecological size spectra". Europhysics Letters (EPL) 55, n.º 6 (septiembre de 2001): 774–80. http://dx.doi.org/10.1209/epl/i2001-00347-0.

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Hamilton, V. E., P. R. Christensen, H. H. Kaplan, C. W. Haberle, A. D. Rogers, T. D. Glotch, L. B. Breitenfeld et al. "Evidence for limited compositional and particle size variation on asteroid (101955) Bennu from thermal infrared spectroscopy". Astronomy & Astrophysics 650 (junio de 2021): A120. http://dx.doi.org/10.1051/0004-6361/202039728.

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Context. Asteroid (101955) Bennu is the target of NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. The spacecraft’s instruments have characterized Bennu at global and local scales to select a sampling site and provide context for the sample that will be returned to Earth. These observations include thermal infrared spectral characterization by the OSIRIS-REx Thermal Emission Spectrometer (OTES). Aims. To understand the degree of compositional and particle size variation on Bennu, and thereby predict the nature of the returned sample, we studied OTES spectra, which are diagnostic of these properties. Methods. We created and mapped spectral indices and compared them with the distribution of geomorphic features. Comparison to laboratory spectra of aqueously altered carbonaceous chondrites constrains the amount of compositional variability that is observable. Results. The OTES spectra exhibit two end-member shapes (or types), and compositional variability appears limited at the spatial resolution of the observations. The global distribution of these spectral types corresponds with the locations of regions composed of (i) large, dark, relatively rough boulders and (ii) relatively smooth regions lacking large boulders. Conclusions. The two spectral types appear to be diagnostic primarily of particle size variations, with contributions from other properties. The spectra resemble experimental data of solid substrates with very thin accumulations (a few to tens of microns) of fine particles (<~65–100 μm). The dustier surfaces commonly correspond with rougher rocks that may produce and/or act as traps for the particles. Anhydrous silicates are limited in abundance, and the bulk mineralogy is consistent with the most aqueously altered carbonaceous chondrites. We expect the returned samples to include these physical and mineralogical characteristics.

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Kobayashi, Takahisa y Ahoro Adachi. "Retrieval of Arbitrarily Shaped Raindrop Size Distributions from Wind Profiler Measurements". Journal of Atmospheric and Oceanic Technology 22, n.º 4 (1 de abril de 2005): 433–42. http://dx.doi.org/10.1175/jtech1705.1.

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Abstract An efficient iterative retrieval method for arbitrarily shaped raindrop size distributions (ITRAN) is developed for Doppler spectra measured with a wind profiler. A measured Doppler spectrum is a convolution of the precipitation spectrum and the turbulent spectrum. Deconvolution of the Doppler spectra is achieved through repeated convolutions. The developed method assumes no prior shape of drop size distributions and automatically obtains raindrop size distributions; additionally, it can be applied to large data volumes. Furthermore, it is insensitive to initial values. The method was applied to both simulated and observed spectra. Derived drop size distributions agree with simulated values. Narrower turbulent spectral widths yield better results. Integral values of median volume diameter (D0), liquid water content (LWC), and radar reflectivity factor are estimated with errors of less than 10%. Accurate vertical profiles of raindrop size distributions result when this method is applied to wind profiler data. The technique performed very well with most observed spectra. Some recovered spectra departed from the corresponding measured spectra, for cases in which a clear-air peak could not be accurately reproduced because of uncertainties in the location of the minimum position between the clear-air echo and the precipitation echo. Statistical relationships between LWC and integral rainfall parameters yield interesting features. The median volume diameter is statistically independent of the LWC and is associated with the large variability of the total number of drops, NT, between events. Vertical profiles from one event show a clear inverse relationship between NT and D0

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10

Cardile, CM, CW Childs y JS Whitton. "The effect of citrate bicarbonate dithionite treatment on standard and soil smectites as evidenced by 57Fe Mössbauer spectroscopy". Soil Research 25, n.º 2 (1987): 145. http://dx.doi.org/10.1071/sr9870145.

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The 57Fe Mossbauer spectra of a selection of smectitic clay fractions of CBD-treated soil samples were measured and computer-fitted with appropriate Fe3+ and Fe2 + resonances. The shape of the Fe3+ spectral envelopes suggested that all the clays were dominated by montmorillonite, contradicting the indications of the Greene-Kelly test. Experiments with untreated and CBD-treated nontronite and montmorillonite showed, however, that the apparent contradiction was probably the result of significant disruption of the smectites by the CBD treatment. The occurrence of this disruption also casts doubt on the validity of using the Greene-Kelly test on CBD-treated samples. The computer-fitted Mossbauer spectra of nontronite with different particle sizes (specifically aggregate size) demonstrated a relationship between particle size and the line-width of the Fe3+ tetrahedral site resonance. This relationship probably reflects an increasing degree of variability in the tetrahedral site with increasing particle size.

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Wang, Weihao, Christian W. Huck y Bin Yang. "NIR model transfer of alkali-soluble polysaccharides in Poria cocos with piecewise direct standardization". NIR news 30, n.º 5-6 (21 de junio de 2019): 6–14. http://dx.doi.org/10.1177/0960336019855218.

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Objective To investigate the feasibility for establishing near-infrared spectra model transfer with traditional Chinese medicine. Method Poria cocos, a kind of fungi (called “ Fuling” in Chinese), was used as an investigative object. NIR quantification model transfer of alkali-soluble polysaccharides in Poria cocos was studied. Spectra were obtained from Thermo Antaris II (master device) and Buchi NIRFlex N-500 (slave device), respectively. Procedures and factors that may have effects on the performance of spectral standardization have been investigated. Spline interpolation was applied to align spectra from two different instruments, and piecewise direct standardization was employed to standardize spectra from slave instrument. Full cross-validation was used to evaluate the result of model transfer. Results Spectral pre-processing including multiplicative signal correction and wavelength selection played an important role in operating the model transfer. Spectra within the region of 9000–6500 cm−1 provided relatively good transfer result. In addition, increasing window size had positive effect on improving the spectral transfer. In this study, a window size of 13 provided the best spectra standardization result. Test validation with five samples produced the best full cross-validation result with the values of correlation coefficient of calibration ([Formula: see text]), correlation coefficient of prediction ([Formula: see text]) and root mean square error of prediction as 0.86, 0.73 and 2.3, respectively. Conclusion In this study, many factors influenced the quality of the transferred slave spectra. And it is hard to provide a pretty good quantitative model transfer result about alkali-soluble polysaccharide in Poria cocos. The following factors have great effects on the quality of model transfer: (i) multiplicative signal correction which is necessary for model building; (ii) increasing the window size which has a positive effect on slave spectra standardization; (iii) a proper wavelength region benefits for model building; (iv) a proper scale of standardization group including proper samples is necessary.

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Umanskaya, M. V., S. V. Bykova y N. G. Tarasova. "Unicellular Plankton Size Structure (Size-Taxonomic and Size-Trophic Spectra) in a Hypertrophic Urban Lake". Известия Российской академии наук. Серия биологическая, n.º 2 (1 de marzo de 2023): 198–210. http://dx.doi.org/10.31857/s102634702270010x.

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The results of an analysis of the size spectra of unicellular plankton (bacteria, algae, ciliates) in the hypertrophic freshwater urban lake (L. Bolshoe Vasilyevskoe, Togliatti, Russia) are presented. Two types of size spectra have been identified in the seasonal cycle. Strong nanoplanctonic maximum formed mainly by phototrophic cyanobacteria and Chlorophyta was found during the period of open water (spring to autumn); picoplankton maximum/maxima (mainly heterotrophic bacteria) and increased proportion of microplankton (heterotrophic and mixotrophic ciliates)–in the ice period. The peculiarity of the studied lake, in contrast to less productive ones is the stability of the plankton size structure over the past 25 years.

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Zhou, Ping, Zhe Zhao, Guangyuan Wei y Hong-Yuan Huo. "Two Simulated Spectral Databases of Lunar Regolith: Method, Validation, and Application". Remote Sensing 14, n.º 2 (7 de enero de 2022): 277. http://dx.doi.org/10.3390/rs14020277.

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Our simulated lunar regolith spectra database, based on the Hapke AMSA radiative transfer model (RTM), is a large supplement to the limited number of lunar spectra data. By analyzing the multiple solutions and applicable scopes of the Hapke model by means of Newton interpolation and the least square optimization method, an improved method was found for the simulation of spectra, but it remained challenging to use to invert mineral abundance. Then, we simulated the spectra, mineral abundance, particle size and maturity of 57 mare and highland samples of the Lunar Soil Characterization Consortium (LSCC) in size groups of 10 µm, 10–20 µm and 20–45 µm. The simulated and measured spectra fit well with each other, with correlation coefficients greater than 0.99 and root mean square errors at a magnitude of 10-3. The parameters of mineral abundance, particle size and maturity are highly consistent with the measured values. Having confirmed the reliability of our simulation method, we analyzed the mechanism, reliability and applicability of the “spectral characteristic angle parameter” proposed by Lucey using the simulated spectral data of lunar regolith. Lucey’s method is only suitable for macro analysis of the entire moon, and the error is large when it is used for areas with high abundance of forsterite or ilmenite. In the spectral simulation of lunar regolith, olivine was subdivided into forsterite and fayalite, and the two end-members were mixed to approximately estimate the effect of the chemical composition of olivine on the spectra, which has been confirmed to be feasible.

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Lo, Su-Chin y Chris W. Brown. "Infrared Spectral Search for Mixtures in Large-Size Libraries". Applied Spectroscopy 45, n.º 10 (diciembre de 1991): 1628–32. http://dx.doi.org/10.1366/0003702914335111.

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A routine for searching large spectral libraries with spectra of mixtures is presented. The dimensionality of a 3169-compound library is reduced to 12% of its original size by using Fourier transform compression and principal component analysis. A principal component regression is performed and used as a prefilter in selecting spectra having features (and chemical groups) similar to those of the unknown mixture. A dot-product metric is then used to identify a target component from the subgroup formed by the prefilter. This is followed by the application of an adaptive filter to remove the similarity of the target component from the subgroup and from the unknown mixture; the search is repeated on the modified data. Successive applications of the adaptive filter will produce minimum residuals if the correct identifications are made. Once the residuals are minimized, a similarity index is calculated to determine the closeness of the unknown mixture spectrum to a spectrum reconstructed from the library spectra. Four out of five two- and three-component spectra were correctly identified. One of the two components in the fifth mixture was correctly identified, and the residual values flagged the improper identification of the second component. After the adaptive filter was applied to the entire library, the second component was correctly identified. Results for this new algorithm are compared to those from four more traditional search routines, which were only completely successful on one of the unknown mixtures.

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Marcus, Matthew A., David A. Shapiro y Young-Sang Yu. "Ptychography Reduces Spectral Distortions Intrinsic to Conventional Zone-Plate-Based X-Ray Spectromicroscopy". Microscopy and Microanalysis 27, n.º 6 (11 de octubre de 2021): 1448–53. http://dx.doi.org/10.1017/s1431927621012733.

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Scanning transmission X-ray microscopy is a powerful method for mapping chemical phases in nano-materials. The point spread function (PSF) of a conventional zone-plate-based microscope limits the achievable spatial resolution and also results in spatially resolved spectra that do not accurately reflect the spatial heterogeneity of the samples when the scale of the detail approaches the probe size. X-ray ptychography, a coherent-scattering-based imaging scheme that effectively removes the probe from the image data, returns accurate spectra from regions smaller than the probe size. We show through simulation how the long tails on the PSF of an x-ray optic can cause spectral distortion near a boundary between two spectrally distinct regions. The resulting apparent point spectra can appear mixed, with the species on one side of the boundary seeming to be present on the other even at a distance from the boundary equal to several times the spatial resolution. We further demonstrate the effect experimentally and show that ptychographic microscopy can return the expected spectra from a model system, whereas conventional microscopy does not.

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Yang, Hai Qing, Bo Yan Kuang y Abdul M. Mouazen. "Size Estimation of Tomato Fruits Based on Spectroscopic Analysis". Advanced Materials Research 225-226 (abril de 2011): 1254–57. http://dx.doi.org/10.4028/www.scientific.net/amr.225-226.1254.

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This study used visible and near-infrared (VIS-NIR) spectroscopy for size estimation of tomato fruits of three cultivars. A mobile, fibre-type, VIS-NIR spectrophotometer (AgroSpec, Tec 5, Germany) with spectral range of 350-2200 nm, was used to measure reflectance spectra of on-vine tomatoes growing from July to September 2010. Spectra were divided into a calibration set (75%) and an independent validation set (25%). A partial least squares regression (PLSR) with leave-one-out cross validation was adopted to establish calibration models between fruit diameter and spectra. Furthermore, the latent variables (LVs) obtained from PLS regression was used as input to back-propagation artificial neural network (BPANN) analysis. Result shows that the prediction of PLSR model can produce good performance with coefficient of determination (R2) of 0.82, root-mean-square error of prediction (RMSEP) of 4.87 mm and residual prediction deviation (RPD) of 2.35. Compared to the PLSR model, the PLS-BPANN model provides considerably higher prediction performance withR2of 0.88, RMSEP of 3.98 mm and RPD of 2.89. It is concluded that VIS-NIR spectroscopy coupled with PLS-BPANN can be adopted successfully for size estimation of tomato fruits.

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Woods, Christopher P., Mark T. Stoelinga y John D. Locatelli. "Size Spectra of Snow Particles Measured in Wintertime Precipitation in the Pacific Northwest". Journal of the Atmospheric Sciences 65, n.º 1 (1 de enero de 2008): 189–205. http://dx.doi.org/10.1175/2007jas2243.1.

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Abstract Particle size spectra collected by the University of Washington’s Convair-580 research aircraft at a variety of altitudes and temperatures in winter frontal and orographic precipitation systems during the Improvement of Microphysical Parameterization through Observational Verification Experiment (IMPROVE) are analyzed in this study. The particle size spectra generally appeared to conform to an exponential size distribution, with well-correlated linear fits between the log of the number concentration and particle diameter. When the particle size spectra were grouped according to the habit composition as determined from airborne imagery, significantly improved correlations between the size spectrum parameters and temperature were obtained. This result could potentially be exploited for specifying the size distribution in a single-moment bulk microphysical scheme, if particle habit is predicted by the scheme. Analyses of “spectral trajectories” suggest that the rime-splintering process was likely responsible for the presence of needle and column habit types and the positive shift in both N0s and λs at temperatures warmer than −10°C.

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Almoukhalalati, Adel, Avijit Shee y Trond Saue. "Nuclear size effects in vibrational spectra". Physical Chemistry Chemical Physics 18, n.º 22 (2016): 15406–17. http://dx.doi.org/10.1039/c6cp01913g.

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Burd, Adrian B. y George A. Jackson. "Modeling Steady-State Particle Size Spectra". Environmental Science & Technology 36, n.º 3 (febrero de 2002): 323–27. http://dx.doi.org/10.1021/es010982n.

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Vinogradov, E. A. "Size effects in vibrational polariton spectra". Ferroelectrics 176, n.º 1 (febrero de 1996): 271–83. http://dx.doi.org/10.1080/00150199608223616.

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Newman, Andrew J., Paul A. Kucera, Christopher R. Williams y Larry F. Bliven. "Snowflake Size Spectra Retrieved from a UHF Vertical Profiler". Journal of Atmospheric and Oceanic Technology 26, n.º 2 (1 de febrero de 2009): 180–99. http://dx.doi.org/10.1175/2008jtecha1105.1.

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Abstract This paper develops a technique for retrieving snowflake size distributions (SSDs) from a vertically pointing 915-MHz vertical profiler. Drop size distributions (DSDs) have been retrieved from 915-MHz profilers for several years using least squares minimization to determine the best-fit DSD to the observed Doppler spectra. This same premise is used to attempt the retrieval of SSDs. A nonlinear search, the Levenberg–Marquardt (LM) method, is used to search the physically realistic solution space and arrive at a best-fit SSD from the Doppler spectra of the profiler. The best fit is assumed to be the minimum of the squared difference of the log of the observed and modeled spectrum power over the precipitation portion of the spectrum. A snowflake video imager (SVI) disdrometer was collocated with the profiler and provided surface estimates of the SSDs. The SVI also provided estimates of crystal type, which is critical in attempting to estimate the density–size relationship. A method to vary the density–size relationship during the event was developed as well. This was necessary to correctly scale the SVI SSDs for comparison to the profiler-estimated distributions. Five events were examined for this study, and good overall agreement was found between the profiler and SVI for the lowest profiler gate (225 m AGL). Vertical profiles of SSDs were also produced and appear to be physically reasonable. Uncertainty estimates using simulated Doppler spectra show that the retrieval uncertainties are larger than that for rainfall and can approach and exceed 100% for situations with large spectral broadening as a result of atmospheric turbulence. The larger uncertainties are attributed to the lack of unique Doppler spectra for quite different SSDs, resulting in a less well-behaved solution space than that of rainfall retrievals.

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Han, Bo-Ping y Milan Straskraba. "Size dependence of biomass spectra and abundance spectra: the optimal distributions". Ecological Modelling 145, n.º 2-3 (noviembre de 2001): 175–87. http://dx.doi.org/10.1016/s0304-3800(01)00389-1.

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KARTHAUS, OLAF, KIYOSHI OKAMOTO, RYOTA CHIBA y KAZUAKI KAGA. "SIZE EFFECT OF CYANINE DYE J-AGGREGATES IN MICROMETER-SIZED POLYMER "DOMES"". International Journal of Nanoscience 01, n.º 05n06 (octubre de 2002): 461–64. http://dx.doi.org/10.1142/s0219581x02000504.

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The fluorescence behavior of 3,3′diethyl-thiacarbocyanine iodide in micrometer-sized polystyrene droplets, or "domes" on glass substrates was investigated. The samples were prepared by casting dilute polymer/dye solutions onto the substrates. A dewetting process leads to the formation of small polymer domes with a diameter of 1–100 μm and a height of 100 nm to several μm. Fluorescence microscopy shows that the dye is incorporated into these polymer domes. It was found that the absorption and fluorescence spectra depend on the size of the polymer domes. Larger domes show red-shifted fluorescence spectra.

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Perczel, Andras y Gerald D. Fasman. "Effect of spectral window size on circular dichroism spectra deconvolution of proteins". Biophysical Chemistry 48, n.º 1 (noviembre de 1993): 19–29. http://dx.doi.org/10.1016/0301-4622(93)80038-k.

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ARSHAD, M. A., J. A. RIPMEESTER y M. SCHNITZER. "ATTEMPTS TO IMPROVE SOLID STATE 13C NMR SPECTRA OF WHOLE MINERAL SOILS". Canadian Journal of Soil Science 68, n.º 3 (1 de agosto de 1988): 593–602. http://dx.doi.org/10.4141/cjss88-057.

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This study describes a number of different preparation techniques for recording solid state 13C NMR spectra of whole mineral soils. Removal of paramagnetic Fe3+ improves the quality of 13C NMR spectra of whole soils and of particle size fractions. The C:Fe ratio appears to be an important indicator for obtaining satisfactory 13C NMR spectra of whole soils and fractions separated from them. If the C:Fe ratio is >> 1, the quality of the spectrum will be good; if the ratio is > 1, a reasonable spectrum will be obtained, but if the ratio is < 1, the spectrum will be poor. Organic-matter-rich soil and particle size fractions separated by a flotation technique produce well-defined 13C NMR spectra, typical of humic materials. Reduction of C-enriched fractions with sodium dithionite and stannous chloride improves the spectral resolution. The data presented herein show that satisfactory solid state 13C NMR spectra can be run on untreated soil particle size fractions, non-magnetic portions of whole soils, and fractions enriched in soil organic matter by flotation, especially after chemical reduction. Key words: 13C NMR spectroscopy, paramagnetic mineral separation

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Tsuda, H. y J. Arends. "Raman Spectra of Human Dental Calculus". Journal of Dental Research 72, n.º 12 (diciembre de 1993): 1609–13. http://dx.doi.org/10.1177/00220345930720121401.

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Raman spectra of human dental calculus have been observed for the first time by use of micro-Raman spectroscopy. The spectral features of calculus were influenced easily by heating caused by laser irradiation. Therefore, the measurements were carried out at relatively low power (5 mW, 1-μm spot size). The spectra could be characterized as phosphate vibrational bands due to the v1, v2, v 3, and v4 modes. The overall spectral features did not resemble those of pure minerals such as brushite, octacalcium phosphate, and hydroxyapatite. There were spectral differences among mixed calculus particles obtained from 18 adults, probably due to variations in local mineral composition and differences among patients. However, the averaged spectral features did not vary significantly with formation period from 1 to 6 months. Freshly removed and stored (5-11 months) calculus also gave comparable Raman spectra. Measurements on a fractured sample indicated that Raman spectra at saliva and dentin interfaces are nearly identical, and major mineral constituents may not vary significantly along the growth axis of calculus.

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27

Olinger, Jill M. y Peter R. Griffiths. "Effects of Sample Dilution and Particle Size/Morphology on Diffuse Reflection Spectra of Carbohydrate Systems in the Near- and Mid-Infrared. Part I: Single Analytes". Applied Spectroscopy 47, n.º 6 (junio de 1993): 687–94. http://dx.doi.org/10.1366/0003702934066965.

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The mid- and near-infrared diffuse reflection spectra of three carbohydrates—microcrystalline cellulose, wheat starch, and sucrose—are examined to determine whether dilution is necessary in either spectral region in order to avoid the effects of specular reflection. As expected, it was found that dilution was not necessary to obtain valid diffuse reflection spectra of samples in the near-infrared, but that dilution was necessary for measuring mid-infrared diffuse reflection spectra free of the effects of specular reflection. The effects of particle size and sample morphology were investigated for sucrose crystals up to 2 mm in dimension. Depending upon the particle size and orientation, the effects of specular reflection can be observed in both near- and mid-infrared diffuse reflection spectra of sucrose. Surface roughness can allow a diffuse reflection component to be measured in the spectra of very large particles where a specular reflection mechanism would typically be expected to predominate.

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28

Chen, Yan Lin, Ming Yan, Yi Ming Sun y Jiao Qun Zhu. "Preparation and Luminescent Properties of Nancrystalline Zro₂:Eu³⁺ by Emulsion Method". Advanced Materials Research 393-395 (noviembre de 2011): 244–48. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.244.

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Europium-doped nanocrystalline ZrO2: Eu3+ powders with different doped concentrations were prepared by emulsion processing method, with different doped concentration and calcination temperature on the material grain size, structure, size and luminescent properties. The results show that: Eu3+ has a stabilizing effect on tetragonal phase of ZrO2. Emission spectra indicates that the main emission peak in the 593m and 608m, “Blue Shift “will occur in 5D0 → 7F2 transition of the emission spectra of sample with the sintering temperature at 1000°C. Samples with the sintering temperature soaring, spectral emission intensity also increases.

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29

Unal, Christine. "High-Resolution Raindrop Size Distribution Retrieval Based on the Doppler Spectrum in the Case of Slant Profiling Radar". Journal of Atmospheric and Oceanic Technology 32, n.º 6 (junio de 2015): 1191–208. http://dx.doi.org/10.1175/jtech-d-13-00225.1.

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AbstractDoppler spectra from vertically profiling radars are usually considered to retrieve the raindrop size distribution (DSD). However, to exploit both fall velocity spectrum and polarimetric measurements, Doppler spectra acquired in slant profiling mode should be explored. Rain DSD samples are obtained from simultaneously measured vertical and slant profile Doppler spectra and evaluated. In particular, the effect of the horizontal wind and the averaging time are investigated.The Doppler spectrum provides a way to retrieve the DSD, the radial wind, and a spectral broadening factor by means of a nonlinear optimization technique. For slant profiling of light rain when the horizontal wind is strong, the DSD results can be affected. Such an effect is demonstrated on a study case of stratiform light rain. Adding a wind profiler mode to the radar simultaneously supplies the horizontal wind and Doppler spectra. Before the retrieval procedure, the Doppler spectra are shifted in velocity to remove the mean horizontal wind contribution. The DSD results are considerably improved.Generally, averaged Doppler spectra are input into this type of algorithm. Instead, high-resolution, low-averaged Doppler spectra are chosen in order to take into account the small-scale variability of the rainfall. Investigating the linear relations at fixed median volume diameter, measured reflectivity-retrieved rainfall rate, for a slant beam, the consistency of the integrated parameters is established for two averaging periods. Nevertheless, the corresponding DSD parameter distributions reveal differences attributed to the averaging of the Doppler spectra.The new aspects are to obtain the same retrieval quality as vertically profiling and highly averaged spectra in an automated way.

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30

Connolly, A. J. y A. S. Szalay. "An Objective Approach to Spectral Classification". Symposium - International Astronomical Union 179 (1998): 376–78. http://dx.doi.org/10.1017/s0074180900129079.

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The next generation of spectroscopic surveys, both Galactic and extra-galactic (e.g., SDSS, 2dF), present the challenge of classifying spectra in an efficient and objective manner. The standard approach to this problem has been to visually classify spectra based on a number of spectral features (e.g., the equivalent widths of emission lines). The size of new spectral surveys (> 106 galaxies) and the desire to compare the luminosity and environments of galaxies with their spectral properties make these techniques infeasible. We describe here an automated classification scheme that is being developed for the SDSS.

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31

Bowen, Bryn, Vishnu Reddy, Mario De Florio, Theodore Kareta, Neil Pearson, Roberto Furfaro, Benjamin Sharkey et al. "Grain Size Effects on Visible and Near-infrared (0.35–2.5 μm) Laboratory Spectra of Ordinary Chondrite and HED Meteorites". Planetary Science Journal 4, n.º 3 (1 de marzo de 2023): 52. http://dx.doi.org/10.3847/psj/acb268.

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Abstract Remote spectral characterization of near-Earth asteroids (NEAs) relies on laboratory spectral calibration to constrain their surface composition, including mineral chemistry and relative mineral abundances. Often these calibrations are based on fine meteorite powders that are representative of regolith observed on large NEAs such as (433) Eros. However, spacecraft observations of smaller NEAs such as (25143) Itokawa, (101955) Bennu, and (162173) Ryugu show surfaces devoid of a thick layer of regolith and instead find variegated landscapes with millimeter-sized particles to meter-scale boulders. Here we present the results of a laboratory study to understand the effects of grain size on the spectral properties of meteorites and how this can impact ground-based characterization of NEAs. Our study focuses on ordinary chondrites (H, L, LL) and HED meteorites, as they comprise ∼90% of all meteorites that fall on Earth. Compared to ordinary chondrites, the spectral band parameters of HED meteorites are less affected by changing grain size. Among the ordinary chondrites, LL chondrites are least affected, but the spectral band parameters and mineral chemistries and abundances for H and L chondrites are most affected by changing grain size. Grain size does not seem to have any significant effect on the taxonomic classification of our meteorite spectra. We also used the Hapke model to investigate trends in single-scattering albedo as a function of grain size and present equations to recover the grain size from a spectrum.

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32

Bett, BJ. "Characteristic benthic size spectra: potential sampling artefacts". Marine Ecology Progress Series 487 (30 de julio de 2013): 1–6. http://dx.doi.org/10.3354/meps10441.

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33

Wolynec, E., V. A. Serrao y M. N. Martins. "Nuclear size effects in virtual photon spectra". Journal of Physics G: Nuclear Physics 13, n.º 4 (abril de 1987): 515–26. http://dx.doi.org/10.1088/0305-4616/13/4/015.

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34

Gerlach, SA, AE Hahn y M. Schrage. "Size spectra of benthic biomass and metabolism". Marine Ecology Progress Series 26 (1985): 161–73. http://dx.doi.org/10.3354/meps026161.

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35

Su, Mingxu, Minghua Xue, Xiaoshu Cai, Zhitao Shang y Feng Xu. "Particle size characterization by ultrasonic attenuation spectra". Particuology 6, n.º 4 (agosto de 2008): 276–81. http://dx.doi.org/10.1016/j.partic.2008.02.001.

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36

Naustvoll, Lars-Johan. "Prey size spectra in naked heterotrophic dinoflagellates". Phycologia 39, n.º 5 (septiembre de 2000): 448–55. http://dx.doi.org/10.2216/i0031-8884-39-5-448.1.

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37

Ahrens, Martin A. y Robert H. Peters. "Patterns and Limitations in Limnoplankton Size Spectra". Canadian Journal of Fisheries and Aquatic Sciences 48, n.º 10 (1 de octubre de 1991): 1967–78. http://dx.doi.org/10.1139/f91-234.

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The hypothesis that biomass is uniformly distributed over logarithmic size classes was evaluated with plankton samples from 15 temperate lake sites in southern Quebec. Over the size range from 0.2 to 1600 μm equivalent spherical diameter (ESD), biomass tended to increase between logarithmic size classes at a median rate of 7%, and numerical abundance declined strongly with increasing size. The slope of the normalized biomass spectrum (reflecting overall trends in the distribution) becomes significantly steeper as total phosphorus decreases and total biomass declines. Hence, more oligotrophic systems have a more uniform biomass distribution and proportionately more small organisms. Over the observed size range, most samples were dominated by a phytoplankton mode between 20 and 50 μm ESD. Because of this dominance and because of the variability of the samples, most sample distributions could not be shown to differ significantly from unimodal lognormal distributions. Efforts to fit bimodal and trimodal distributions met with limited success, likely because only 39 size classes could be used. Simple mathematical descriptors of size spectra are insensitive to substantial departures from both linear and lognormal models, and therefore, variaion in the parameters of such descriptions are ineffective correlates of departures from average patterns.

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38

Jung, Sukgeun y Edward D. Houde. "Fish biomass size spectra in Chesapeake Bay". Estuaries 28, n.º 2 (abril de 2005): 226–40. http://dx.doi.org/10.1007/bf02732857.

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39

Sprules, W. Gary y M. Munawar. "Plankton Size Spectra in Relation to Ecosystem Productivity, Size, and Perturbation". Canadian Journal of Fisheries and Aquatic Sciences 43, n.º 9 (1 de septiembre de 1986): 1789–94. http://dx.doi.org/10.1139/f86-222.

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Quantification and comparisons of the structure of open-water plankton communities from 25 inland lakes of Ontario, from the Laurentian Great Lakes Superior, Huron, St. Clair, Ontario, and Erie, and from the Central Gyre in the North Pacific Ocean were made on the basis of the normalized biomass size spectrum. Residual variation around the fitted straight lines (corresponding to a theoretical steady state) was least for the large, oligotrophic Lake Superior and the North Pacific Gyre and greatest for eutrophic Saginaw Bay and shallow Lake Erie, suggesting progressive departure from steady-state conditions with increasing system productivity. The slopes of the normalized spectra decrease with increasing eutrophy, indicating that nannoplankton abundances are similar in all communities studied, but that associated zooplankton abundances vary by 2.5 orders of magnitude. Our results suggest that parameterization of particle-size models for prediction of potential fish production must be adjusted according to the size and productivity of the ecosystem, and that routine monitoring of communities by the normalized biomass spectrum could provide early warning of nutrient or toxic stress in aquatic ecosystems.

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40

Petchey, Owen L. y Andrea Belgrano. "Body-size distributions and size-spectra: universal indicators of ecological status?" Biology Letters 6, n.º 4 (5 de mayo de 2010): 434–37. http://dx.doi.org/10.1098/rsbl.2010.0240.

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The sizes of individual organisms, rather than their taxonomy, are used to inform management and conservation in some aquatic ecosystems. The European Science Foundation Research Network, SIZEMIC, facilitates integration of such approaches with the more taxonomic approaches used in terrestrial ecology. During its 4-year tenure, the Network is bringing together researchers from disciplines including theorists, empiricists, government employees, and practitioners, via a series of meetings, working groups and research visits. The research conducted suggests that organismal size, with a generous helping of taxonomy, provides the most probable route to universal indicators of ecological status.

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41

Lin, M. E., R. Reifenberger, A. Ramachandra y R. P. Andres. "Size-dependent field-emission spectra from nanometer-size supported gold clusters". Physical Review B 46, n.º 23 (15 de diciembre de 1992): 15498–502. http://dx.doi.org/10.1103/physrevb.46.15498.

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42

Bruning, Eric C. y Donald R. MacGorman. "Theory and Observations of Controls on Lightning Flash Size Spectra". Journal of the Atmospheric Sciences 70, n.º 12 (22 de noviembre de 2013): 4012–29. http://dx.doi.org/10.1175/jas-d-12-0289.1.

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Abstract Previous analyses of very high frequency (VHF) Lightning Mapping Array (LMA) observations relative to the location of deep convective updrafts have noted a systematic pattern in flash characteristics. In and near strong updrafts, flashes tend to be smaller and more frequent, while flashes far from strong vertical drafts exhibit the opposite tendency. This study quantitatively tests these past anecdotal observations using LMA data for two supercell storms that occurred in Oklahoma in 2004. The data support a prediction from electrostatics that frequent breakdown and large flash extents are opposed. An energetic scaling that combines flash rate and flash area exhibits a power-law scaling regime on scales of a few kilometers and a maximum in flash energy at about 10 km. The spectral shape is surprisingly consistent across a range of moderate to large flash rates. The shape of this lightning flash energy spectrum is similar to that expected of turbulent kinetic energy spectra in thunderstorms. In line with the hypothesized role of convective motions as the generator of thunderstorm electrical energy, the correspondence between kinematic and electrical energy spectra suggests that advection of charge-bearing precipitation by the storm’s flow, including in turbulent eddies, couples the electrical and kinematic properties of a thunderstorm.

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43

Liao, Jin, Charles A. Brock, Daniel M. Murphy, Donna T. Sueper, André Welti y Ann M. Middlebrook. "Single-particle measurements of bouncing particles and in situ collection efficiency from an airborne aerosol mass spectrometer (AMS) with light-scattering detection". Atmospheric Measurement Techniques 10, n.º 10 (17 de octubre de 2017): 3801–20. http://dx.doi.org/10.5194/amt-10-3801-2017.

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Abstract. A light-scattering module was coupled to an airborne, compact time-of-flight aerosol mass spectrometer (LS-AMS) to investigate collection efficiency (CE) while obtaining nonrefractory aerosol chemical composition measurements during the Southeast Nexus (SENEX) campaign. In this instrument, particles scatter light from an internal laser beam and trigger saving individual particle mass spectra. Nearly all of the single-particle data with mass spectra that were triggered by scattered light signals were from particles larger than ∼ 280 nm in vacuum aerodynamic diameter. Over 33 000 particles are characterized as either prompt (27 %), delayed (15 %), or null (58 %), according to the time and intensity of their total mass spectral signals. The particle mass from single-particle spectra is proportional to that derived from the light-scattering diameter (dva-LS) but not to that from the particle time-of-flight (PToF) diameter (dva-MS) from the time of the maximum mass spectral signal. The total mass spectral signal from delayed particles was about 80 % of that from prompt ones for the same dva-LS. Both field and laboratory data indicate that the relative intensities of various ions in the prompt spectra show more fragmentation compared to the delayed spectra. The particles with a delayed mass spectral signal likely bounced off the vaporizer and vaporized later on another surface within the confines of the ionization source. Because delayed particles are detected by the mass spectrometer later than expected from their dva-LS size, they can affect the interpretation of particle size (PToF) mass distributions, especially at larger sizes. The CE, measured by the average number or mass fractions of particles optically detected that had measurable mass spectra, varied significantly (0.2–0.9) in different air masses. The measured CE agreed well with a previous parameterization when CE > 0.5 for acidic particles but was sometimes lower than the minimum parameterized CE of 0.5.

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44

Krumsick, KJ y JAD Fisher. "Community size spectra provide indicators of ecosystem recovery on the Newfoundland and Labrador shelf". Marine Ecology Progress Series 635 (6 de febrero de 2020): 123–37. http://dx.doi.org/10.3354/meps13212.

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Species- and size-selective overexploitation often have ecosystem-wide impacts that are evident in community size spectra. To both derive potential ecosystem targets for community rebuilding and assess contemporary indicators relative to these targets, we constructed theoretical size spectra to predict pristine biomass densities using a combination of species- and size-specific nitrogen stable isotope signatures and a range of trophic efficiencies and primary productivity estimates within and among 3 sub-regions of the Newfoundland and Labrador shelf. Theoretical size spectra were compared to empirically derived size spectra using trawl survey data. The descending slopes of the empirically determined size spectra were between 1.25 and 2.42 times steeper than the theoretical slopes. The percentage of the theoretical distribution represented by the empirical size structure ranged between 1.1 and 29.4%, with the closest and furthest estimates associated with the smallest- and largest-sized fishes, respectively, and strongly influenced by estimates of trophic efficiency and primary productivity. Regional variation was also observed, with southern regions reaching 1.3-32.3% of the theoretical biomass density and the northernmost region reaching only 0-8.3%. Importantly, the descending slopes varied depending on fish size, with biomass density of larger sizes decreasing faster than that of smaller sizes. Variations among sub-regions and fish guilds were also observed. These analyses provide a means to derive potential ecosystem targets and indicators through which recovery of fish communities can be monitored and assessed.

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45

Iurina, Viktoriia, Vitaly V. Neshchimenko y Chun Dong Li. "Size Effect on Optical Properties of Silicon Dioxide Hollow Particles". Solid State Phenomena 312 (noviembre de 2020): 26–31. http://dx.doi.org/10.4028/www.scientific.net/ssp.312.26.

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The optical properties of silicon dioxide hollow particles with different size were investigated in UV/visible/near-IR region, as well as X-ray photoelectron spectra were analyzed. Synthesis of SiO2 hollow particles was carried out using a template method. It was established that hollow particle reflectance lower than bulk microparticles. Absorptance in the red and near infrared spectral ranges increases with decreasing size of hollow particles, but in the UV-region conversely. This is due to different absorption centers.

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46

Janik, Leslie J., José M. Soriano-Disla y Sean T. Forrester. "Feasibility of handheld mid-infrared spectroscopy to predict particle size distribution: influence of soil field condition and utilisation of existing spectral libraries". Soil Research 58, n.º 6 (2020): 528. http://dx.doi.org/10.1071/sr20097.

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Partial least-squares regression (PLSR), using spectra from a handheld mid-infrared instrument (the ExoScan), was tested for the prediction of particle size distribution. Soils were sampled from agricultural sites in the Eyre Peninsula under field conditions and with varying degrees of soil preparation. Issues relevant to field sampling were identified, such as sample heterogeneity, micro-aggregate size and moisture content. The PLSR models for particle size distribution were derived with the varying degrees of preparation. Cross-validation of clay content in the as-received in situ soils resulted in low accuracy: coefficient of determination (R2) = 0.55 and root mean square error (RMSE) = 7%. This was improved by manual mixing, drying, sieving to < 2 mm and fine grinding, resulting in R2 values of 0.64, 0.75 and 0.81, and RMSE of 6%, 5% and 4% respectively; less improvement resulted for sand, with corresponding R2 values of 0.82, 0.88, 0.91 and 0.89, and RMSE of 10%, 8%, 6% and 7%. Predictions for silt remained poor. Where only archival benchtop calibration models were available, predictions of clay contents for spectra scanned with the handheld ExoScan spectrometer resulted in high error because of spectral intensity mismatch between benchtop and handheld spectra (R2 = 0.72, RMSE = 24.2% and bias = 21%). Pre-processing the benchtop spectra by piecewise direct standardisation resulted in more successful predictions (R2 = 0.73, RMSE = 6.7% and bias = –1.5%), confirming the advantage of piecewise direct standardisation for prediction from archival spectral libraries.

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47

Cattaneo, Antonella. "Size Spectra of Benthic Communities in Laurentian Streams". Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 12 (1 de diciembre de 1993): 2659–66. http://dx.doi.org/10.1139/f93-289.

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The size spectra of benthic invertebrates in streams appear to differ from those reported in planktonic systems, but could reflect the narrow taxonomic scope of previous studies. When algae, protozoans, and invertebrates growing on rocks in three Laurentian streams (Québec) were grouped in logarithmically increasing size classes, patterns in the distribution of biomass were consistent over sites and dates, despite large differences in taxonomic composition. Peaks and troughs were observed in the size spectra, but the biomass of the various size classes usually lay within an order of magnitude of the mean of all classes. The slopes of the normalized size spectra were always shallower than −1 (median = −0.91) indicating a slight biomass increase in the larger size classes. Strongly peaked spectra previously observed for stream invertebrates were smoothed by the inclusion of algae and protozoans. Comparison with size spectra described for benthic and pianktonic communities in lakes and oceans, showed remarkable similarities among habitats. These findings suggest that roughly similar biomass in logarithmic size classes is a general community pattern not restricted to the peculiarities of plankton communities. A size-based approach could be useful to simplify the description of complex stream communities.

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48

Tian, Lin, Gerald M. Heymsfield, Lihua Li, Andrew J. Heymsfield, Aaron Bansemer, Cynthia H. Twohy y Ramesh C. Srivastava. "A Study of Cirrus Ice Particle Size Distribution Using TC4 Observations". Journal of the Atmospheric Sciences 67, n.º 1 (1 de enero de 2010): 195–216. http://dx.doi.org/10.1175/2009jas3114.1.

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Abstract An analysis of two days of in situ observations of ice particle size spectra, in convectively generated cirrus, obtained during NASA’s Tropical Composition, Cloud, and Climate Coupling (TC4) mission is presented. The observed spectra are examined for their fit to the exponential, gamma, and lognormal function distributions. Characteristic particle size and concentration density scales are determined using two (for the exponential) or three (for the gamma and lognormal functions) moments of the spectra. It is shown that transformed exponential, gamma, and lognormal distributions should collapse onto standard curves. An examination of the transformed spectra, and of deviations of the transformed spectra from the standard curves, shows that the lognormal function provides a better fit to the observed spectra.

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49

Gómez-Canchong, Paúl, José M. Blanco y Renato A. Quiñones. "On the use of biomass size spectra linear adjustments to design ecosystem indicators". Scientia Marina 77, n.º 2 (5 de abril de 2013): 257–68. http://dx.doi.org/10.3989/scimar.03708.22a.

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50

Gentsar, P. O., M. V. Vuichyk, M. V. Isaev y P. O. Lischuk. "Optical Properties of Porous Silicon p-Si (100)". Фізика і хімія твердого тіла 20, n.º 3 (18 de octubre de 2019): 264–68. http://dx.doi.org/10.15330/pcss.20.3.264-268.

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In this paper the reflectance spectra and transmission spectra of p-Si (100) porous silicon (PS) and silicon wires in the spectral range of 200 ÷ 1800 nm were investigated. Pore size of PS was 5 μm (lpor Si layer) and 50 μm (lpor Si layer) with porosity of 45 %, 55 % and 65 %. The length of silicon wires varies from 5.5 μm, to 50 μm with a porosity of 60 %. The decrease in the band gap of p-Si (100) porous silicon and silicon wires which grown on both sides of p-Si (100) as compared to the single crystal p-Si (100) is explained by the quantum-sized effect that occurs in the investigated objects.

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