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排序方式: 共有387条查询结果,搜索用时 15 毫秒
41.
Designing of epoxy resin systems for cryogenic use 总被引:2,自引:0,他引:2
The mechanical and thermal properties of several types of epoxy systems were designed based on the chemical structure, network structure and morphology aiming at cryogenic application. In this research di-epoxies or multifunctional epoxies were cured by several kinds of hardeners such as anhydride, amine or phenol and were blended with polycarbonate, carboxyl-terminated butadiene acrylonitrile copolymer or phenoxy. The mechanical properties and thermal properties of these cured epoxies were measured at room and liquid nitrogen temperature. It was found that the two-dimensional network structured linear polymer shows high performance even at cryogenic temperature. It was concluded that the controls of the structures are very important to optimize epoxy systems for cryogenic application. 相似文献
42.
Ken-Ichi Ohguchi Katsuhiko Sasaki Masahiro Ishibashi 《Journal of Electronic Materials》2006,35(1):132-139
A method to separate plasticity and creep is discussed for a quantitative evaluation of the plastic, transient creep, and
steady-state creep deformations of solder alloys. The method of separation employs an elasto-plastic-creep constitutive model
comprised of the sum of the plastic, transient creep, and steady-state creep deformations. The plastic deformation is expressed
by the Ramberg-Osgood law, the steady-state creep deformation by Garofalo’s creep law, and the transient creep deformation
by a model proposed here. A method to estimate the material constants in the elasto-plastic-creep constitutive model is also
proposed. The method of separation of the various deformations is applied to the deformation of the lead-free solder alloy
Sn/3Ag/0.5Cu and the lead-containing solder alloy Sn/37Pb to compare the differences in the plastic, transient creep, and
steady-state creep deformations. The method of separation provides a powerful tool to select the optimum lead-free solder
alloys for solder joints of electronic devices. 相似文献
43.
44.
T. Nishijima H. Sekiguchi S. Matsuda N. Shiono 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1997,130(1-4):557-563
A Si pn junction diode and a GaAs Schottky diode were prepared for studying the basic mechanism of charge collection followed by high energy charged particle incidence in order to improve the resistance against single event upset. A 2 μm wide and 20 μm long rectangular Al electrode attached to a circular Al electrode with a 50 μm diameter was made on a 2.5 μm thick epilayer (minority carrier density 2 × 1015 /cm3). Both a Schottky electrode of Al (5 μm × 110 μm) and two ohmic electrodes of AuGe/Ni (110 μm × 110 μm) were made on a 2 μm thick epilayer (7.3 × 1015 /cm3) grown on a semi insulator GaAs substrate (1 × 107 Ω cm). The internal device structure was examined by the IBIC (Ion Beam Induced Charge) method using a 2 MeV He+ ion microbeam. IBIC images clearly show an Al electrode, the SiO2, and an epilayer. These results were then used to improve the qualities of the test diodes. 相似文献
45.
Shin-Ichi Hirano† Toshinobu Yogo† Ko-Ichi Kikuta† Ken-Ichi Noda† Masao Ichida‡ Arao Nakamura‡ 《Journal of the American Ceramic Society》1995,78(11):2956-2960
Crack-free and highly transparent KTiOPO4 (KTP) thin films were synthesized by the sol-gel method using a homogeneous precursor solution prepared from ("BuO)2 -P(O)(OH), Ti(OEt)4 , and KOEt in EtOH. Precipitated powders from the solution crystallized directly to KTP above 550°C. Polycrystalline KTP thin films were obtained at 600°C on various substrates. On NdAlO3 (100) substrates, KTP films with (101) and (240) preferred orientations were formed at 600°C. KTP films on glass substrates showed a refractive index of 1.75 and an absorption edge of 350 nm. KTP films exhibited the second harmonic generation of the 532 nm light on irradiaton with 1064 nm light. 相似文献
46.
This paper proposes a novel multiwavelength simultaneous monitoring (MSM) circuit that uses the wavelength crossover properties of an arrayed-waveguide grating (AWG). The MSM circuit consists of an AWG, a stabilized semiconductor laser as a reference light, and logarithmic amplifiers. The AWG chip is a simple planar-lightwave-circuit chip. It functions as multiple optical filters, and make it possible to monitor multiple wavelengths simultaneously. The MSM circuit, locked to the reference wavelength produced by a semiconductor laser stabilized to the 1547.49 mn 13C2 H2 absorption line, achieved 10 MHz resolution and 30 MHz stability for 24 h in the stable polarization state. Measurement accuracy of better than 1.1 GHz can be realized even if the state of polarization of the input light fluctuates at random. Multiwavelength simultaneous monitoring is successfully demonstrated using tunable lasers 相似文献
47.
Diffusion of vanadium,chromium, and manganese in copper 总被引:2,自引:0,他引:2
Kazutomo Hoshino Yoshiaki Iijima Ken-Ichi Hirano 《Metallurgical and Materials Transactions A》1977,8(3):469-472
The diffusion coefficients of vanadium, chromium and manaanese in copper have been determined by the residual activity method
with radioactive tracers V48, Cr51 and Mn54 in the temperature ranges between 955 and 1342 K, between 999 and 1338 K and between 971 and 1253 K, respectively. The temperature
dependence of the diffusion coefficients is expressed by the following Arrhenius equations along with the probable errors:D
V/Cu = (2.48
-0.44
+0.53
) x 10−4 exp [-(215 ± 2) kJ mol−1/RT] m2 per s,D
Cr/Cu = (0.337
-0.090
+0.124
) x 10−4 exp [-(195 ± 3) kJ mol−1/RT] m2 per s,D
Mn/Cu = (1.02
-0.18
+0.22
) x 10−4 exp [-(200 ± 2) kJ mol−1/RT] m2 per s.
Anomalous penetration profiles for the diffusion of Cr51 and Mn54 in the present results suggest that experimental results onD
Cr/Cu andD
Mn/Cu in the past have been influenced by oxidation and evaporation of the chemically active radiotracers during annealing for
diffusion.
formerly Graduate Student, Tohoku University 相似文献
48.
49.
Mass transfer coefficients between particles and liquids in a slurry bubble column and a three-phase fluidized bed containing small size particles were obtained with two mass transfer systems: (1) K+ –Na+ ion-exchange in cation-exchange resin bead beds, including anion-exchange resin beads as inert particles; (2) zinc dissolution by HCl in zinc-plated glass bead beds, and in beds of non-plated glass beads. Operating parameters were gas velocity, liquid velocity, particle diameter, and particle concentration. The dependence of mass transfer coefficients on these parameters is discussed from the viewpoint of the energy supplied into the systems. Correlations of the experimental data using dimensionless groups are compared to previous correlations. 相似文献
50.
Shoji Suehiro Takeshi Yamada Thein Kyu Ken-Ichi Fujita Takeji Hashimoto Hiromichi Kawai 《Polymer Engineering and Science》1979,19(13):929-939
Dynamic x-ray diffraction is employed to scrutinize the structural origin of the α mechanical dispersion of a highdensity polyethylene having preferentially oriented rownucleated cylindritic texture around the machine direction (MD). Results indicate that the α1 dispersion is associated with two kinds of orientation processes of crystallites: (1) the orientation process involving the rotation of crystallites around the crystal b-axis (lamellar axis) dominates in the MD specimen; (2) the other process accompanying the rotation of crystallites or lamellar segments around their crystal a-axis dominates in the TD (transverse direction) specimen. The complex apparent crystal lattice compliances show no frequency dependence in the real component and no appreciable value in the imaginary component, indicating that the α1 process is definitely associated with the intercrystalline process, but not relavent to the intracrystal process. However, at elevated temperatures, the complex lattice compliances exhibit a remarkable frequency dependence, suggesting that the α2 dispersion concomitant to intracrystalline nature takes place in this time scale. The α2 dispersion was found to be more pronounced upon stretching along the lamellar axis (TD) than normal to it (MD). 相似文献