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排序方式: 共有459条查询结果,搜索用时 15 毫秒
81.
钛/铜(Ti/Cu)作为ITER 第一壁Be/CuCrZr 热等静压连接中间过渡层,形成了多层中间金属相结构,容易在Ti/Cu 金属相之间产生裂纹等缺陷。采用CuCrZr 代替Be,经过与Be/CuCrZr 相同的热等静压工艺,制作了多个CuCrZr/Ti/Cu/CuCrZr 连接件,对Ti/Cu 连接接头进行深入分析。对连接件分别进行未退火、400℃和500℃ 退火处理,去应力退火后对接头强度和缺陷分布的影响进行了研究。研究结果表明,中间钛层的两侧都形成了三层Ti/Cu 扩散层,分别为Cu4Ti、CuTi 和CuTi2。纯铜侧的Cu4Ti 厚度比CuCrZr 侧的厚,使得裂纹几乎全部分布于铜侧的Cu4Ti 与CuTi 交界处,拉伸样品极易在此处发生脆性断裂。随着退火温度升高,裂纹的产生和扩展减少。 相似文献
82.
The multi-layer computing model is developed to calculate wide-angle neutron spectra, in the range from0° to 180° with a 5° step, produced by bombarding a thick beryllium target with deuterons. The double-differential cross-sections(DDCSs) for the ~9 Be(d, xn) reaction are calculated using the TALYS-1.8 code. They are in agreement with the experimental data, and are much better than the PHITS-JQMD/GEM results at 15°, 30°, 45° and 60° neutron emission angles for deuteron energy of 10.0 MeV. In the TALYS-1.8 code, neutron contributions from direct reactions(break-up, stripping and knock-out reactions) are controlled by adjustable parameters, which describe the basic characteristics of typical direct reactions and control the relative intensity and the position of the ridgy hillock at the tail of DDCSs. It is found that the typical calculated wide-angle neutron spectra for different neutron emission angles and neutron angular distributions agree quite well with the experimental data for 13.5 MeV deuterons. The multi-layer computing model can reproduce the experimental data reasonably well by optimizing the adjustable parameters in the TALYS-1.8 code. Given the good agreement with the experimental data, the multi-layer computing model could provide better predictions of wide-angle neutron energy spectra, neutron angular distributions and neutron yields for the ~9 Be(d, xn) reaction neutron source. 相似文献
83.
J.P. Kar 《Applied Surface Science》2009,255(7):4087-4092
ZnO nanostructures were grown on silicon, porous silicon, ZnO/Si and AlN/Si substrates by low-temperature aqueous synthesis method. The shape of nanostructures greatly depends on the underlying surface. Scattered ZnO nanorods were observed on silicon substrate, whereas aligned ZnO nanowires were obtained by introducing sputtered ZnO film as a seed layer. Furthermore, both the combination of nanorods and the bunch of nanowires were found on porous silicon substrates, whereas platelet-like morphology was observed on AlN/Si substrates. XRD patterns suggest the crystalline nature of aqueous-grown ZnO nanostructures and high-resolution transmission electron microscopy images confirm the single-crystalline growth of the ZnO nanorods along [0 0 1] direction. Room-temperature photoluminescence characterization clearly shows a band-edge luminescence along with a visible luminescence in the yellow spectral range. 相似文献
84.
Epitaxial Sb-doped SnO2 (0 0 1) thin film on a TiO2 (0 0 1) substrate was successfully prepared by laser-assisted metal organic deposition at room temperature. The effects of the precursor thin film and laser fluence on the resistivity, carrier concentration, and mobility of the Sb-doped SnO2 film were investigated. The resistivity of the Sb-doped SnO2 film prepared by direct irradiation to metal organic film is one order of magnitude lower than that of film prepared by irradiation to amorphous Sb-doped SnO2 film. From an analysis of Hall measurements, the difference between the resistivity of the Sb-doped SnO2 film prepared using the metal organic precursor film and that of amorphous precursor film appears to be caused by the mobility. Direct conversion of the metal organic compound by excimer laser irradiation was found to be effective for preparing epitaxial Sb-doped SnO2 film with low resistivity. 相似文献
85.
David J. Hwang Moosung Kim Kuniaki Hiromatsu Hojeong Jeon Costas P. Grigoropoulos 《Applied Physics A: Materials Science & Processing》2009,96(2):385-390
Three-dimensional flow-through microchannels were fabricated inside bulk fused silica glass via ultrashort pulsed laser direct
writing. The device fabrication sequence takes advantage of the nonlinear volumetric absorption in glass and the subsequent
preferential chemical etching process. Optical waveguides were also written into the glass specimen and integrated with the
fluidic conduits. Flow tests using both fluorescent particles and red blood cells (RBCs) were conducted on various three-dimensional
channel configurations. Experiments showed the possibility for laser-induced cell processing inside the microchannels. To
evaluate cytometer functionality, RBCs were detected inside the manufactured microchannel via both transmission and fluorescence
probing. 相似文献
86.
J. J. Camacho M. Santos L. Díaz J. M. L. Poyato 《Applied Physics A: Materials Science & Processing》2009,94(2):373-380
We have used ferrocene and paraffin wax as novel precursor and solvent for the growth of iron oxide nanoparticles. The proposed
method of growth has several advantages over existing methods of growth using iron pentacarbonyl a precursor. Highly crystalline
and monodispersed particles are obtained which assemble in two- and three-dimensional hexagonal closed packed superlattices.
Growth kinetics has been studied by varying concentration of the precursor and time of growth. A phenomenological model has
been proposed to explain the growth kinetics. 相似文献
87.
V. L. Gayou B. Salazar-Hernandez G. Zavala P. Santiago J. A. Ascencio 《Applied Physics A: Materials Science & Processing》2009,94(4):735-738
In this work, we report the synthesis of ZnS nanostructures by a simple and eco-friendly method that makes possible producing
nanoflakes at room temperature. Scanning electron microscopy and transmission electron microscopy methods (mainly bright-field,
high resolution and high angle annular dark-field) were used to identify and study the obtained nanostructures. The structure
of these nanoflakes consists of nanosized crystalline particles around 1.5 to 3 nm. Domains with different contrast of nanometer-size
diameters are formed in the self-assembled nanoflakes as a result of a noncompact arrangement of nanocrystallites during agglomeration
and differences in the presence of the organic passivation agent. Agglomeration can be attributed to the amount of crystallites
generated at the beginning of the reaction or to an anisotropic interaction between phosphate ions and the surfaces of ZnS
clusters, and consequently a bottom-up synthesis is considered, which opens a simple route for the production of nanomaterials
with the inclusion of extra elements by a simple way. 相似文献
88.
S. Gleyzes A. El Amili R. A. Cornelussen P. Lalanne C. I. Westbrook A. Aspect J. Estève G. Moreau A. Martinez X. Lafosse L. Ferlazzo J. C. Harmand D. Mailly A. Ramdane 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(1):107-111
We study a Fabry-Perot cavity formed from a ridge waveguide on a AlGaAs substrate. We experimentally determined the propagation
losses in the waveguide at 780 nm, the wavelength of Rb atoms. We have also made a numerical and analytical estimate of the
losses induced by the presence of the gap which would allow the interaction of cold atoms with the cavity field. We found
that the intrinsic finesse of the gapped cavity can be on the order of F∼30, which, when one takes into account the losses
due to mirror transmission, corresponds to a cooperativity parameter for our system C∼1. 相似文献
89.
M. Abe N. Nishio N. Hanyu M. Tada A. Sandhu H. Handa 《Journal of magnetism and magnetic materials》2009,321(7):645-649
Ferrite nanobeads were synthesized from an aqueous solution utilizing Fe2+ to Fe3+ oxidation for use as magnetic carriers in bioscreening, bio-molecular recognition and anti-cancer diagnosis and therapy. The beads had a crystal structure that was intermediate between Fe3O4 and γ-Fe2O3. Functional biomolecules were strongly conjugated onto the surfaces of the ferrite beads via COOH and SH groups. The addition of ferrite seed crystals (3-8 nm in size) together with a disaccharide enabled the synthesis of monodisperse, spherical ferrite beads with average diameters (d¯) between 50 and 150 nm and relative deviation Δd/d¯=9-16%. Hollow ferrite nano-spheres (d¯=150-450 nm, Δd/d¯≈10%) were prepared using silica spheres as templates, which were dissolved in NaOH solution. Ferrite beads 40 nm in size were encapsulated in polymer spheres of styrene and polymerized glycidyl methacrylate (poly-GMA), 184±9 nm in diameter. They were used for high throughput bioscreening system for affinity purification of target proteins which make specific bindings to anti-cancer drugs, porphyrins, environment hormones, etc. 相似文献
90.