排序方式: 共有117条查询结果,搜索用时 921 毫秒
41.
F. M. Pigozzo E. Autizi A. -D. Capobianco N. Argiolas M. Bazzan C. Sada 《Optical and Quantum Electronics》2006,38(9-11):889-901
We present a feasiblity study of a new method for enhancing the continuously phase matched second harmonic generation in 2D PPLN optical waveguides fabricated using the off-center Czochralski technique and proton-exchange. We show that a periodic variation of the nonlinear coefficient along the transverse coordinate permits for efficient energetic exchanges. 相似文献
42.
Thermal transporting properties of electrically conductive polyaniline films as organic thermoelectric materials 总被引:1,自引:0,他引:1
Thermal transporting properties of electrically conductive polyaniline films were first investigated in wide range of temperatures
above room temperature as organic thermoelectric materials. Thermal conductivities of various protonic acid-doped polyaniline
films were measured by combination of a laser flash method and a differential scanning calorimeter in relation with electrical
conductivity and a kind of dopant. The thermal conductivities thus measured are in the range of conventional organic polymers,
indicating that the doped polyaniline films have extremely low thermal conductivities among electrically conductive materials,
and have correlation with neither electrical conductivity, nor a kind of dopant. Consequently the polyaniline film, which
shows very high electrical conductivity, has comparable thermoelectric figure-of-merit (ZT) with feasible inorganic thermoelectric materials such as iron silicide.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
43.
Copper diffusion in ion-exchanged soda-lime glass 总被引:3,自引:0,他引:3
F. Gonella A. Quaranta S. Padovani C. Sada F. D’Acapito C. Maurizio G. Battaglin E. Cattaruzza 《Applied Physics A: Materials Science & Processing》2005,81(5):1065-1071
Cu-alkali ion exchange in silicate glasses gives rise to a peculiar copper distribution, with the presence of both the Cu2+ and Cu+ oxidation states. Grazing incidence X-ray absorption near-edge structure spectroscopy and secondary ion mass spectrometry were performed on different ion-exchanged samples. The results show that the Cu2+/Cu+ ratio is strongly depth-dependent. The relative presence of the two species throughout the exchanged region turns out to be governed by their different diffusion regimes, while the chemistry of the red-ox process is shown to play a minor role. A phenomenological model is proposed to describe the diffusion process. PACS 61.10.Ht; 61.43.Fs; 82.65.+r; 67.80.Mg 相似文献
44.
F. Gourbilleau P. Choppinet C. Dufour M. Levalois R. Madelon C. Sada G. Battaglin R. Rizk 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):341
Among the systems used as optical amplifiers, we propose an original way to elaborate photoluminescent materials. The method is based on the reactive RF magnetron co-sputtering of SiO2 and Er2O3 controlled by the hydrogen dilution rate in the plasma gas. The relationship between the photoluminescence properties and the structural characteristics is evidenced through the variation of two parameters in the deposition process: the hydrogen partial pressure within the plasma and the sputtered surface ratio of Er2O3 and SiO2 targets. 相似文献
45.
46.
M. V. Ciampolillo N. Argiolas A. Zaltron M. Bazzan C. Sada 《Applied Physics A: Materials Science & Processing》2011,105(1):111-118
Iron-doped X-cut lithium niobate crystals were prepared by means of thermal diffusion from thin film varying in a systematic
way the process parameters such as temperature and diffusion duration. Secondary Ion Mass Spectrometry was exploited to characterize
the iron in-depth profiles. The evolution of the composition of the Fe thin film in the range between 600°C and 800°C was
studied, and the diffusion coefficient at different temperatures in the range between 900°C and 1050°C and the activation
energy of the diffusion process were estimated. 相似文献
47.
E. Cattaruzza G. Battaglin F. Gonella A. Quaranta G. Mariotto C. Sada S. Ali 《Journal of Non》2011,357(8-9):1846-1850
Field-assisted solid-state ion exchange (FASSIE) is a suitable way to dope glasses with metallic ions. This approach is a promising technique for the production of glass waveguides containing either bivalent or trivalent ions, allowing the doping of glass surfaces with multivalent ions which could not diffuse into the glass matrix by means of the usual thermal ion-exchange process in molten salt baths. In this paper, results on the diffusion of chromium in silicate glasses are presented. A metallic chromium film deposited on the top of the glass substrates was used as the metal ions supplier. The doped layers were investigated by secondary ion mass and Rutherford backscattering spectrometries, as well as by micro-Raman spectroscopy. Chromium entered the glass matrices for some hundreds of nanometers, depending on the process temperature and the applied electric field. Strong compositional modification of the treated glasses was detected, related to alkali and alkali-earth elements distribution. For field-assisted solid-state diffusion, borosilicate glasses seem to be more stable matrices than the soda-lime silicate ones. 相似文献
48.
Jakapan Chantana Yanqiu Yang Yasushi Sobajima Chitose Sada Akihisa Matsuda Hiroaki Okamoto 《Journal of Non》2012,358(17):2319-2323
A novel type of substrate named “Ag–SP substrate”, in which silver nanoparticles are incorporated, is introduced and utilized as a back reflector for hydrogenated microcrystalline-silicon solar cell in a substrate-type (n-i-p) configuration. Optical and morphological analyses of Ag–SP substrates fabricated with various sizes of silver nanoparticles are systematically performed. It is shown that silver nanoparticles in Ag–SP substrate structure can lead to significant scattering of light when their diameter increases up to 300 nm. Furthermore, the photocurrent of the solar cell fabricated on an Ag–SP substrate with RMS roughness as small as 16.5 nm and a proper lateral diameter (approximately 300 nm) of silver nanoparticles is improved as compared to that of the solar cell prepared on reference textured substrate with RMS roughness of 25.3 nm, owing to strong scattering of light by silver nanoparticles in the red-infrared region. 相似文献
49.
Shohei Hayashi Yasuharu Satoh Yasushi Ogasawara Chitose Maruyama Yoshimitsu Hamano Tetsuro Ujihara Tohru Dairi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2348-2352
Polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) are essential fatty acids for humans. Some microorganisms biosynthesize these PUFAs through PUFA synthases composed of four subunits with multiple catalytic domains. These PUFA synthases each create a specific PUFA without undesirable byproducts, even though the multiple catalytic domains in each large subunit are very similar. However, the detailed biosynthetic pathways and mechanisms for controlling final‐product profiles are still obscure. In this study, the FabA‐type dehydratase domain (DHFabA) in the C‐subunit and the polyketide synthase‐type dehydratase domain (DHPKS) in the B‐subunit of ARA synthase were revealed to be essential for ARA biosynthesis by in vivo gene exchange assays. Furthermore, in vitro analysis with truncated recombinant enzymes and C4‐ to C8‐acyl ACP substrates showed that ARA and EPA synthases utilized two types of DH domains, DHPKS and DHFabA, depending on the carbon‐chain length, to introduce either saturation or cis double bonds to growing acyl chains. 相似文献
50.
Steady-state permeation rates for pure CO2 and CH4 and their binary mixtures through homogeneous dense cellulose triacetate membranes have been measured at three temperatures between 20 and 40°C and pressures up to 2.8 MPa. The pressure dependence of the mean permeability coefficient for CO2 can be described by the total immobilization model in conjunction with a modified free-volume model. No appreciable pressure dependence of the permeability coefficient for CH4 is observed, while the permeability coefficients for CH4 in binary mixture of CO2 and CH4 depend on applied gas pressure. The pressure dependences of the mean permeability coefficients for the components in the binary mixture are discussed in terms of the above mobility model. Membrane plasticization induced by CO2 affects permeation by both gases. 相似文献