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11.
N. V. Kozyrev G. V. Sakovich Sen Tchel Sou 《Combustion, Explosion, and Shock Waves》2005,41(5):589-590
The synthesis of detonation diamonds from a mixture of RDX labeled by C14 isotope with soot was studied experimentally. It was shown that a considerable portion of the diamonds (24.7 ± 3.4)% are
formed from the carbon of RDX molecules. The degree of conversion of the carbon atoms of soot to the diamond phase is (16.0
± 1.6)%.
__________
Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 117–118, September–October, 2005. 相似文献
12.
S.K. Chan S.K. Lok G. Wang Y. Cai N. Wang K.S. Wong I.K. Sou 《Journal of Electronic Materials》2008,37(9):1433-1437
Ultrathin ZnS nanowires (NWs) were grown on a sapphire (0001) substrate at 430°C by the molecular-beam epitaxy (MBE) technique
using self-assembled Au droplets as the catalyst. It was found that these NWs mainly consist of the cubic phase but a small
portion was in the hexagonal phase. The analysis of the temperature-dependent band-edge (BE) emission of these NWs and that
of a ZnS thin film revealed that the energy shift of the interband transition on temperature in ZnS is mainly attributed to
the electron–phonon interactions. The observed blue shift of the BE emission of ZnS NWs could be quantitatively explained
by the confinement of the excited excitons in the NW geometry. 相似文献
13.
Short-channel effects, substrate leakage current, and average electron velocity are investigated for 0.1-μm-gate-length GaAs MESFETs fabricated using the SAINT (self-aligned implantation for n+-layer technology) process. The threshold-voltage shift was scaled by the aspect ratio of the channel thickness to the gate length ( a /L g). The substrate leakage current in a sub-quarter-micrometer MESFET is completely suppressed by the buried p layers and shallow n+-layers. The average electron velocity for 0.1- to 0.2-μm-gate-length FETs is estimated to be 3×106 cm/s from the analysis of intrinsic FET parameters. This high value indicates electron velocity overshoot. Moreover, a very high f T of 93.1 GHz has been attained by the 0.1-μm SAINT MESFET 相似文献
14.
Short Message Service (SMS) is the most popular mobile data service today. In Taiwan, a subscriber sends more than 200 short messages per year on average. The huge demand for SMS significantly increases network traffic, and it is essential that mobile operators should provide efficient SMS delivery mechanism. In this paper, we study the short message retransmission policies and derive some facts about these policies. Then, we propose an analytic model to investigate the short message retransmission performance. The analytic model is validated against simulation experiments. We also collect SMS statistics from a commercial mobile telecommunications network. Our study indicates that the performance trends for the analytic/simulation models and the measured data are consistent. 相似文献
15.
From the temperature dependence of the hole concentration in unirradiated lightly Al-doped 4H-SiC epilayers, an Al acceptor with EV + 0.2 eV, which is an Al atom (AlSi) at a Si sublattice site, and an unknown deep acceptor with EV + 0.35 eV are found, where EV is the top of the valence band. Both the densities are similar. With irradiation of 0.2 MeV electrons the Al acceptor density is reduced, while the unknown deep acceptor density is increased. Judging from the minimum electron energy required to displace a substitutional C atom (Cs) or the AlSi, the bond between the AlSi and its nearest neighbor Cs is broken due to the displacement of the Cs by this irradiation. Moreover, the displacement of the Cs results in the creation of a complex (AlSi-VC) of AlSi and a carbon vacancy (VC), indicating that the possible origin of the deep acceptor with EV + 0.35 eV is AlSi-VC. 相似文献
16.
描述了ZnSxSe1-x光盲紫外液晶光阀的结构和工作原理 ,并从器件的电学模型出发 ,着重讨论了整体器件对ZnSxSe1-x光敏层的特殊要求。采用分子束外延技术在ITO导电玻璃上制备了具有 (111)面定向生长结构的ZnSxSe1-x多晶薄膜 ,通过控制反应时的生长参数 ,制备出了符合器件设计要求的光敏层薄膜。室温下 ,该薄膜的紫外 /可见光响应对比度大于10 3 ;响应波长截止边可通过控制薄膜中的Se组分 ,在 (36 0~ 4 10 )nm范围内连续可调 ;薄膜的暗电阻率在 (4 32× 10 9~ 2 0 3×10 11)Ω·m之间 ,并随着晶粒的增大而减小 ;在液晶光阀工作的低频段 (<2 0 0Hz) ,其光 /暗阻抗比在 0 2 2~ 0 36之间。 相似文献
17.
Sou Miyata Kazuhito Yoshida Hayato Shirokura Mikihiro Kashio Kazukiyo Nagai 《Polymer International》2009,58(10):1148-1159
BACKGROUND: ABA‐type poly(methyl methacrylate) (PMMA) and fluorine‐containing polyimide triblock copolymers are potentially beneficial for electric materials. In the work reported here, triblock copolymers with various block lengths were prepared from fluorine‐containing difunctional polyimide macroinitiators and methyl methacrylate monomer through atom‐transfer radical polymerization. The effects of structure on their solid and thermal properties were studied. RESULTS: The weight ratios of the triblock copolymers derived using thermogravimetric analysis were shown to be almost identical to the ratios determined using 1H NMR. The solid properties (film density and maximum d‐spacing value) and thermal properties (glass transition and thermal expansion) were shown to be strongly dependent on the weight ratios of both PMMA and polyimide components. Furthermore, a porous film, which showed a lower dielectric constant of 2.48 at 1 MHz, could be prepared by heating a triblock copolymer film to induce the thermal degradation of the PMMA component. CONCLUSION: The use of the polyimide macroinitiator was useful in the preparation of ABA‐type triblock copolymers to control each block length that influences the solid and thermal properties. Additionally, the triblock copolymers have great potential in preparing porous polyimides in the application of electric materials as interlayer insulation membranes of large‐scale integration. Copyright © 2009 Society of Chemical Industry 相似文献
18.
The novel Fe/Nb co-doped SrCo1 ? 2x(Fe,Nb)xO3 ? δ (x = 0.05, 0.10) perovskite oxides were synthesized by the solid-state method. Structural and chemical stability of the SrCo1 ? 2x(Fe,Nb)xO3 ? δ (x = 0.05, 0.10) oxides were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffraction (XRD). The results demonstrated that the structural and chemical stability of the Fe/Nb co-doped SrCo1 ? 2x(Fe,Nb)xO3 ? δ (x = 0.05, 0.10) is improved significantly. The oxygen sorption properties of the SrCo1 ? 2x(Fe,Nb)xO3 ? δ (x = 0.05, 0.10) oxides were investigated between 300–900 °C in air, and the high oxygen sorption capacity of 11.5 and 10.3 mL O2 (STP)/g oxide, respectively, are obtained. 相似文献
19.
Hosokai S Kasiwaya Y Matsui K Okinaka N Akiyama T 《Environmental science & technology》2011,45(2):821-826
This paper describes the reduction of hematite with ammonia for ironmaking, in which the effect of temperature on the products was examined. The results showed that the reduction process began at 430 °C during heating, and with an increase in temperature, the reduction mechanism changed apparently from a direct reduction of ammonia (Fe(2)O(3) + 2NH(3) → 2Fe + N(2) + 3H(2)O) to an indirect reduction via the thermal decomposition of ammonia (2NH(3) → N(2) + 3H(2), Fe(2)O(3) + 3H(2) → 2Fe + 3H(2)O) at temperatures over 530 °C. The final product obtained at 600 and 700 °C was pure metallic iron, in contrast with that formed at 450 °C, that is, a mixture of metallic iron and iron nitride. The results suggest the possibility of using ammonia as a reducing agent for carbonless ironmaking, which is operated at a much lower temperature than 900 °C in conventional coal-based ironmaking. 相似文献
20.
Onodera K. Nishimura K. Asai K. Sugitani S. 《Electron Devices, IEEE Transactions on》1993,40(1):18-24
Fully ion-implanted n+ self-aligned GaAs MESFETs with high microwave and ultra-low-noise performance have been fabricated. T-shaped gate structures composed of Au/WSiN are employed to reduce gate resistance effectively. A very thin and high-quality channel with high carrier concentration can be formed by adopting the optimum annealing temperature for the channel, and the channel surface suffers almost no damage by using ECR plasma RIE for gate formation. GaAs MESFETs with a gate length as short as 0.35 μm demonstrated a maximum oscillation frequency of 76 GHz. At an operating frequency of 18 GHz, a minimum noise figure of 0.81 dB with an associated gain of 7.7 dB is obtained. A K f factor of 1.4 estimated by Fukui's noise figure equation, which is comparable to those of AlGaAs/GaAs HEMTs with the same geometry, reveals that the quality of the channel is very high 相似文献