金属材料超高周疲劳行为的Monte-Carlo模拟

<正>基于Tanaka-Mura的微观位错模型并结合结构可靠性及灵敏度的统计理论,采用MATLAB自编程序对金属材料S-N曲线的分散特性进行了Monte-Carlo模拟分析,并对比了SUJ2钢的旋转弯曲疲劳实验数据,最后根据结构可靠性灵敏度理论分析了超高周疲劳失效概率的各影响因素的敏感性。

HIRFL-CSRm内靶实验终端上TPC性能的Monte-Carlo研究

基于Monte Carlo方法对HIRFL CSRm上的TPC的性能进行了模拟.研究了磁场、读出电极几何尺寸、灵敏丝距以及读出电极平面与灵敏丝平面之间的距离等参数对TPC性能的影响,给出了TPC的一些最佳设计参数.

复合式高能γ探测器优化设计Monte Carlo模拟计算

用MonteCarlo方法系统模拟计算了以NaI晶体与BGO晶体为探测介质的clover与cluster复合式高能γ探测器的效率 .对于相同的介质几何 ,BGO复合式探测器的全能峰效率远高于相应的NaI复合式探测器 .用多块76× 1 2 7BGO晶体制作成的clover与cluster复合式高能γ探测器对 2 2 0MeV的γ光子的全能峰特征效率仍然高于 40 % ,绝对效率增加因子达 2 4与 2 7.

Theoretical investigation on excitation, ionization and capture in H(1s, 2s)+H(1s, 2s) collisions

Cross sections of electron- loss in H( 1s)+ H( 1s) collisions and total collisional destruction of H( 2s) in H( 1s) + H( 2s) collisions are calculated by four- body classical- trajectory Monte Carlo ( CTMC) method and compared with previous theoretical and experimental data over the energy range of 4 - 100 keV. For the former a good agreement is obtained within di. erent four- body CTMC calculations, and for the incident energy Ep > 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approximation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H( 2p), single- and double- ionization and H- formation in H( 2s)+ H( 2s) collisions are calculated in the energy range of 4 - 100 keV for the. rst time, and compared with those in H( 1s)+ H( 1s) and H( 1s)+ H( 2s) collisions.

The direct electrochemistry behavior of Cyt c on the modified glassy carbon electrode by SBA-15 with a high-redox potential

It is discovered that SBA-15 (santa barbara amorphous) can provide the favorable microenvironments and optimal direct electron-transfer tunnels (DETT) of immobilizing cytochrome c (Cyt c) by the preferred orientation on it. A high-redox potential (254 mV vs. Ag/AgCl) was obtained on glassy carbon (GC) electrode modified by immobilizing Cyt c on rod-like SBA-15. With ultraviolet-visible (UV-vis), circular dichroism (CD), FTIR and cyclic voltammetry, it was demonstrated that immobilization made Cyt c exhibits stable and ideal electrochemical characteristics while the biological activity of immobilized Cyt c is retained as usual.

A bifunctional structure for the direct electron transfer of Cytochrome c

It was found that silicon dioxide (SiO2) nanoparticles modified onto glassy carbon (GC) electrode exhibited a dramatic promotion on the direct electron transfer of Cytochrome c (Cyt c). The corresponding mechanism was discussed based on the electrochemical characteristics and a spatial geometrical model of the bifunctional structure. The model could offer insight to the study of biosensors and bioreactors without chemical mediator and serve as a basis for their fabrication. (c) 2008 Elsevier Ltd. All rights reserved.

Syntheses of fully sulfonated polyaniline nano-networks and its application to the direct electrochemistry of cytochrome c

Fully sulfonated polyaniline nano-particles, nano-fibrils and nano-networks have been achieved for the first time by electrochemical homopolymerization of orthanilic acid using a three-step electrochemical deposition procedure in a mixed solvent of acetonitrile (ACN) and water. The diameter of the uniform nano-particles is about 60nm, and the nano-fibrils can be organized in two-dimensional (21)) or three-dimensional (313) non-periodic networks with good electrical contact. Average distance between contacts is about 850 and 600 nm for a 2D and 3D system, respectively. The details of the poly(orthanilic acid) (POA) nano-structure were examined with a field emission scanning electron microscope (SEM). The structure and properties of POA were characterized with FTIR, UV-vis and electrochemical methods. The 3D POA nano-networks coated platinum electrode gave a direct electrochemical behavior of horse heart cytochrome c (Cyt c) immobilized on this electrode surface, a pair of well-defined redox waves with formal potential (E-ol) of -0.032 V (versus Ag/AgCl) was achieved. The interaction between Cyt c and POA makes the formal potential shift negatively compared to that of Cyt c in solution. Spectrophotometric and electrochemical methods were used to investigate the interaction of Cyt c with POA.