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排序方式: 共有429条查询结果,搜索用时 15 毫秒
41.
Julia Kostina Galina Bondarenko Maria Gringolts Alexander Rodionov Olga Rusakova Alexander Alentiev Alexander Yakimanskii Yulia Bogdanova Vladimir Gerasimov 《Polymer International》2013,62(11):1566-1574
One of the most important areas of current research is the study of the influence of the prehistory of samples of amorphous glassy polymers on their physical and chemical properties. The study of structural changes by high temperature IR spectroscopy compared with of quantum chemical calculations allows for an understanding of the mechanism and nature of such processes. The changes in the structure of the polymer chain depending on the type of solvent used in the formation of the films are demonstrated using the examples of several different classes of polymers. In turn, the impact of such changes in the structure on the physical and chemical properties of the polymer films is demonstrated. © 2013 Society of Chemical Industry 相似文献
42.
Boris A. Trofimov Marina V. Markova Inna V. Tatarinova Al’bina I. Mikhaleva Lyudmila V. Morozova Ol’ga V. Petrova Lyubov’ N. Sobenina Konstantin B. Petrushenko Tamara I. Vakul'skaya Spartak S. Khutsishvili Galina F. Prozorova 《Synthetic Metals》2010,160(23-24):2573-2580
I2-doped and pyrrole ring-iodinated semi-conducting oligomers of N-vinyl-3-alkyl-2-phenylpyrroles have been synthesized by free-radical polymerization of the above monomers (AIBN, 2–5 wt%, 60–80 °C) and further exposure of the oligomers obtained to I2 vapor. The parent oligomers exhibit paramagnetic and fluorescent properties and stable up to 300–370 °C. 相似文献
43.
Measurement of minority carrier lifetime in n-type MBE HgCdTe and its dependence on annealing 总被引:1,自引:0,他引:1
D. D. Edwall R. E. DeWames W. V. McLevige J. G. Pasko J. M. Arias 《Journal of Electronic Materials》1998,27(6):698-702
Results are presented for minority carrier lifetime in n-type molecular beam epitaxy Hg1−xCdxTe with x ranging from 0.2 to 0.6. It was found that the lifetime was unintentionally degraded by post-growth annealing under
Hg saturated conditions in a H2 atmosphere that was both time and temperature dependent. This effect was minimal or non-existent for x∼0.2 material, but
very strong for x ≥ 0.3. Hydrogen was identified as responsible for this degradation. Identical annealing in a He atmosphere
avoids this degradation and results in neartheoretical lifetime values for carrier concentrations as low 1 × 1015 cm−3 in ≥0.3 material. Modeling was carried out for x∼0.2 and x∼0.4 material that shows the extent to which lifetime is reduced
by Shockley-Real-Hall recombination for carrier concentrations below 1 × 1015 cm−3, as well as for layers annealed in H2. It appears that annealing in H2 results in a deep recombination center in wider bandgap HgCdTe that lowers the lifetime without affecting the majority carrier
concentration and mobility. 相似文献
44.
45.
Georgy Terentyuk Elizaveta Panfilova Vitaly Khanadeev Daniil Chumakov Elina Genina Alexey Bashkatov Valery Tuchin Alla Bucharskaya Galina Maslyakova Nikolai Khlebtsov Boris Khlebtsov 《Nano Research》2014,7(3):325-337
Nanocomposites (NCs) consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin (HP) have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies (PDT + PTT) in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared (NIR) laser irradiation. These modalities were used for a combined PDT + PTT treatment of large (about 3 cm3) solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT + PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume. 相似文献
46.
M. Carmody J. G. Pasko D. Edwall M. Daraselia L. A. Almeida J. Molstad J. H. Dinan J. K. Markunas Y. Chen G. Brill N. K. Dhar 《Journal of Electronic Materials》2004,33(6):531-537
In the past several years, we have made significant progress in the growth of CdTe buffer layers on Si wafers using molecular
beam epitaxy (MBE) as well as the growth of HgCdTe onto this substrate as an alternative to the growth of HgCdTe on bulk CdZnTe
wafers. These developments have focused primarily on mid-wavelength infrared (MWIR) HgCdTe and have led to successful demonstrations
of high-performance 1024×1024 focal plane arrays (FPAs) using Rockwell Scientific’s double-layer planar heterostructure (DLPH)
architecture. We are currently attempting to extend the HgCdTe-on-Si technology to the long wavelength infrared (LWIR) and
very long wavelength infrared (VLWIR) regimes. This is made difficult because the large lattice-parameter mismatch between
Si and CdTe/HgCdTe results in a high density of threading dislocations (typically, >5E6 cm−2), and these dislocations act as conductive pathways for tunneling currents that reduce the RoA and increase the dark current of the diodes. To assess the current state of the LWIR art, we fabricated a set of test diodes
from LWIR HgCdTe grown on Si. Silicon wafers with either CdTe or CdSeTe buffer layers were used. Test results at both 78 K
and 40 K are presented and discussed in terms of threading dislocation density. Diode characteristics are compared with LWIR
HgCdTe grown on bulk CdZnTe. 相似文献
47.
L. O. Bubulac J. Bajaj W. E. Tennant M. Zandian J. Pasko W. V. Mc Levige 《Journal of Electronic Materials》1996,25(8):1312-1317
This work presents characterization of implanted and annealed double layer planar heterostructure HgCdTe for p-on-n photovoltaic
devices. Our observation is that compositional redistribution in the structure during implantation/ annealing process differs
from that expected from classical composition gradient driven interdiffusion and impacts the placement of the electrical junction
with respect to the metallurgical heterointerface, which in turn affects quantum efficiency and RoA. The observed anomalous interdiffusion results in much wider cap layers with reduced composition difference between base
and cap layer composition. The compositional redistribution can, however, be controlled by varying the material structure
parameters and the implant/anneal conditions. Examples are presented for dose and implanted species variation. A model is
proposed based on the fast diffusion in the irradiation induced damage region of the ion implantation. In addition, we demonstrate
spatial uniformity obtained on molecular beam epitaxy (MBE) material of the compositional and implanted species profile. This
reflects spatial uniformity of the ion implantation/annealing Processes and of the MBE material characteristics. 相似文献
48.
VK Zuev AB Stoliarzh AI Kulenkov EV Galina VV Kuzin IG Buzel' GV Lashchenov 《Canadian Metallurgical Quarterly》1998,319(5):35-8, 96
In the department of microsurgery of A.A. Vishnevsky Central Hospital the transplantation and transposition of the at the gunshot injuries of the extremities have begun to execute since 1990. For this time 94 surgical interventions have been conducted at 88 wounded: 57 transplantations and 37 transpositions of the bloody tissues. The transplantation and transposition of the vascularized complexes of tissues with application of microsurgical technique is the effective method of the treatment of the wounded in the extremities. In the conditions of the local armed conflicts it is necessary to provide deployment of the department of microsurgery at stages of the specialized medical care. 相似文献
49.
Majid Zandian D. Scott J. Garnett D. D. Edwall J. Pasko M. Farris M. Daraselia J. M. Arias J. Bajaj D. N. B. Hall S. Jacobson G. Luppino S. Parker 《Journal of Electronic Materials》2005,34(6):891-897
Growth of Hg1−xCdxTe by molecular beam epitaxy (MBE) has been under development since the early 1980s at Rockwell Scientific Company (RSC),
formerly the Rockwell Science Center; and we have shown that high-performance and highly reproducible MBE HgCdTe double heterostructure
planar p-on-n devices can be produced with high throughput for various single- and multiplecolor infrared applications. In
this paper, we present data on Hg1−xCdxTe epitaxial layers grown in a ten-inch production MBE system. For growth of HgCdTe, standard effusion cells containing CdTe
and Te were used, in addition to a Hg source. The system is equipped with reflection high energy electron diffraction (RHEED)
and spectral ellipsometry in addition to other fully automated electrical and optical monitoring systems. The HgCdTe heterostructures
grown in our large ten-inch Riber 49 MBE system have outstanding structural characteristics with etch-pit densities (EPDs)
in the low 104 cm−2 range, Hall carrier concentration in low 1014 cm−3, and void density <1000 cm2. The epilayers were grown on near lattice-matched (211)B Cd0.96Zn0.04Te substrates. High-performance mid wavelength infrared (MWIR) devices were fabricated with R0A values of 7.2×106 Ω-cm2 at 110 K, and the quantum efficiency without an antireflection coating was 71.5% for cutoff wavelength of 5.21 μm at 37 K.
For short wavelength infrared (SWIR) devices, an R0A value of 9.4×105 Ω-cm2 at 200 K was obtained and quantum efficiency without an antireflection coating was 64% for cutoff wavelength of 2.61 μm at
37 K. These R0A values are comparable to our trend line values in this temperature range. 相似文献
50.
Bimler DL Paramei GV 《Journal of the Optical Society of America. A, Optics, image science, and vision》2005,22(10):2120-2136
Luminance-dependent change in color appearance--the Bezold-Brücke effect--was investigated in protanopes and related to that in normal trichromats. Spectral lights were presented at six luminance levels covering mesopic, low, and high photopic vision-across three log steps from 0.76 to 760 Td. To judge color appearance, a variant of the color-naming method was used with four primary basic color terms and a "White" response. This modification enabled us to examine apparent saturation changes along with the Bezold-Brücke hue shift. Color-naming frequency functions were acquired across ten presentations of each stimulus. Since protanopes name colors idiosyncratically, changes in color appearance cannot be quantified directly from the color-naming functions. To circumvent the difficulty, these functions were transformed into color similarity measures for analysis with multidimensional scaling purported to reconstruct individual color spaces. In these, luminance-dependent shifts in color appearance were represented by means of geometric displacements. We found that for normal trichromats, shifts measured in this way agreed with those derived in our study directly, and with the hue shifts reported in earlier studies. For protanopes, contrary to some models of dichromatic vision, changes in color appearance are significant and indicate superimposed shifts in hue and saturation. The results obtained for normal trichromats, especially for protanopes, imply that nonlinearity in the yellow-blue opponent system is insufficient to explain the Bezold-Brücke effect, given the nature of the saturation shift and the demonstrated divergence between unique hues and invariant hues. 相似文献