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991.
石英玻璃低能质子辐照损伤动力学研究 总被引:2,自引:0,他引:2
地面模拟研究了JGS3光学石英玻璃在真空、热沉和能量低于200keV的低能质子辐照下表面光学性能变化的基本规律.并建立了辐照损伤色心演化的动力学唯象模型。试验结果表明.大通量低能质子辐照对石英玻璃表层具有明显的表面损伤效应。随着辐照吸收剂量的增加,光密度变化先以线性规律迅速增加.加进一步增加时逐渐呈现饱和趋势;采用较高能量辐照作用后光密度变化出现饱和趋势的拐点提前,且饱和数值降低。根据对试验结果的分析,建立了低能质子辐照下石英玻璃色心演化的动力学模型.并给出了光密度变化的表达式。采用模型结果进行数学模拟,模拟曲线与试验结果曲线相似。因此所建立的动力学模型可以用来定量描述低能质子辐照下石英玻璃光学性能随辐照吸收剂量的变化规律。 相似文献
992.
993.
More and more e-tailers (platforms) are allowing manufacturers direct access to customers. Two common contracts are offered by platforms to manufacturers: the revenue sharing contract where a platform appropriates a portion of the manufacturer’s revenue, and the fixed fee contract where a platform charges a fixed rent for each sale. Using an analytical model, this paper studies the interrelationship between a platform’s contract choice and a manufacturer’s product quality decision. We find that if product quality is exogenously given, the platform will always adopt the revenue sharing contract. If the manufacturer endogenously decides the quality, however, the platform’s contract choice may be changed. This is because the revenue sharing contract, compared to fixed fee, leads to a lower selling price of the manufacturer, whereas the fixed fee contract can motivate a higher quality than does revenue sharing. As a result, a large (small) market heterogeneity induces the platform to adopt the revenue sharing (fixed fee) contract. We also extend the model to several directions, finding that longer product line, manufacturer competition, lower marginal production cost, and higher platform cost all tend to induce the platform to put forward a fixed fee contract; while if quality decision is less flexible than contract decision, the platform is more ready to embrace revenue sharing. Besides, when there are two platforms competing for the same market, they should differentiate their contract choices so as to mitigate competition. 相似文献
994.
Pico-second photoelectric characteristic in manganite oxide La0.67Ca0.33MnO3 films 总被引:1,自引:0,他引:1 下载免费PDF全文
Ultrafast photoelectric characteristic has been observed in La0.67Ca0.33MnO3 films on tilted SrTiO3 substrates. A pico-second (ps) open-circuit photovoltage of the perovskite manganese oxide films has been obtained when the films were irradiated by a 1.064μm laser pulse of 25 ps duration. The rise time and full width at half-maximum of the photovoltage pulse are ~300 ps and ~700 ps, respectively. The photovoltaic sensitivity was as large as ~500 mV/mJ. 相似文献
995.
Z.-W.?He W.-X.?Sun X.-Q.?Liu D.-Y.?Xu J.?Gou Y.-Y.?WangEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,48(4):463-468
Nanoporous SiO2 thin films with ultra-low
dielectric constants were synthesized using a molecular template method.
Uniform films with pore size between 10 and 20 nm were obtained as observed
by N2 adsorption/desorption isotherms and transmission electron
microscopy. Fourier transform infrared spectroscopy (FTIR) and differential
thermal analysis were carried out to investigate the effect of n-hexane
washing on structural properties before and after the surface modification
process. The results showed that –OH bonds were substituted with –CH3 bonds in the films as a result of modification of trimethylchlorosilane
(TMCS)/n-hexane solution. Four kinds of model were used to analyze the
relationship between porosity and dielectric constant of the films, where
the dielectric constant was determined from capacitance-voltage
measurements. The investigation indicated that the corresponding
relationship was in accord with that estimated by the Rayleigh model. 相似文献
996.
Electron acceleration in a tightly focused ultra-intensity linear polarized laser beam is investigated numerically. It has been found that the acceleration is strong phase dependent and is periodic to the variety of the initial laser field phase. When optimal initial parameters are chosen, the electron can be accelerated effectively. The accelerated electrons are emitted in pulses of which the full width is less than the half period of the laser field. 相似文献
997.
何炳生 《高等学校计算数学学报》2020,(1):22-47
我们对文章的结构做这样的安排:第二节给出本文需要的预备知识;第三节简述单个目标函数问题(1.1)的己有算法和求解可能遇到的困难,第四节给出解决问题的预测-校正方法;第五节和第六节对问题(1.2)分别陈述己有方法的固有困难和我们提出的解决方案.最后,在第七节中,我们为提出的方法给出统一的算法框架,证明这类算法的收敛性和遍历意义下的收敛速率,同时给出我们的一些结论. 相似文献
998.
The continuous-wave laser properties of an efficient diode-pumped Nd:GdVO4 crystal operating at formed with a simple plane-concave cavity have been studied. With the incident pump power of 21 W, an output power of 6.9 W was obtained, giving an optical conversion efficiency of 32.8% and a slope efficiency of 35.3%. The laser characterization of two different Nd3+-doped concentration of Nd:GdVO4 crystals were studied. 相似文献
999.
本文对GB型空间进行了若干讨论,得到了一些结果。 设X为Banach空间,X为X的共轭空间,B(X,X)为X到X的所有有界线性算子组成的空间。如果X中的弱收敛序列为弱收敛序列,则称X为GB型空间。Grothendieck.A于1953年证明了l~∞是GB型空间。显然自反空间是GB型空间。 相似文献
1000.
The π phase-shifting Fourier transform technique is introduced into the surface profile measurement of moving objects. A digital grating comprising two regions, which have a π phase shifting is projected onto the object. Two line-scan CCD cameras are used to capture two deformed fringe patterns with π phase shifting at the same time. As the object is moving, each point at the object surface can be captured twice. The digital correlation method is used to calibrate the experimental system. The zero-order component can be eliminated by subtracting intensities of the same surface point in two captured images. And then the phase can be extracted by Fourier transform without the disturbance of zero-order component. Experimental results demonstrate that this method is feasible for the moving surface profile detection and the measurable slope of height variation can be extended. 相似文献