Bcc Fe晶界模型简化方法的第一性原理研究

基于密度泛函理论,计算了bcc Fe中Σ5(310)晶界平面位置处He_nV(n≤2)团簇的性质,同时以此数据结果为判断标准,分析了两种简化晶界模型的优劣,这两种简化晶界模型分别是自由表面晶界模型和重构的双晶界模型.选取三种不同取向的He_2V团簇,分别从结构、能量、计算资源消耗等多种角度进行对比,分析了所建模型的合理性与可行性.结果表明,两种简化模型都能够显著提高计算效率,但是自由表面晶界模型与初始完整晶界模型的计算结果更加吻合.同种简化方法及思路亦可应用于诸如非对称晶界的更复杂的晶界结构.     

TiO2-石墨烯光催化剂：制备及引入石墨烯的方法对光催化性能的影响

利用溶胶-凝胶法原位制备了二氧化钛/石墨烯(TiO2-GE)复合光催化剂,研究了纯TiO2以及不同方法制备的TiO2-GE复合光催化剂对亚甲基蓝及罗丹明B光催化降解性能。结果表明:石墨烯的引入提高了TiO2的光催活性,这主要是得益于石墨烯优异的电子传输性能及较好吸附特性。不同方法制备TiO2-GE复合催化剂的光催化活性也存在较大差别。原位制备的TiO2-GE复合光催化剂表现出最佳的光催化活性。     

Tunneling Radiation from a Static Spherically Symmetric Black Hole Surroundedby Quintessence

By extending the Parikh-Wilczek tunneling framework, we investigate the tunneling radiation of uncharged massless particles from a static spherically symmetric black hole surrounded by quintessence. The results are consistent with an underlying unitary theory.     

Massive Particles' de Sitter Tunneling in (3+1)-Dimensional de Sitter Spacetimes

In this paper, massive particles' Hawking radiation via tunneling from cosmological horizon of a (3+1)-dimensional de Sitter spacetime is investigated. According to Parikh's theory, when a particle tunnels across the cosmological horizon, the effective geometry is Schwarzschild-de Sitter spacetime. In this effective spacetime, a massive particle can be treated as a de Broglie S-wave. WKB method is used. The emission spectrum is obtained, and it takes the same functional form as that of massless particles.     

间歇热源驱动下的吸附式制冷系统运行特性研究

本文以一个连续回热型吸附式制冷系统为例,通过对间歇热源驱动下的系统运行过程的动态仿真,分析了热源的变化及其热源中的蓄热对于系统解吸过程的影响,提出了热源间断时间的判断方法以及在间歇热源驱动下的系统的控制方案。     

对吸附制冷性能参数SCP物理意义的分析

评价吸附式制冷系统的主要性能指标包括COP与SCP等参数,其中SCP是单位吸附剂质量的制冷功率。SCP的计算包括按照单床运行进行计算以及按照多床循环进行计算等方式,这些计算值所代表的物理意义并不相同,本文通过对吸附式制冷不同循环方式中SCP物理意义的分析,更加明确了SCP不同计算方式所适用的场合及所代表的意义。     

低速轴流压气机单转子旋转失速三维数值模拟和实验比较

本文通过求解三维不可压N-S方程,对三级低速轴流压气机第一级的孤立转子进行数值模拟,在出口加上节流阀进行了非定常计算,得到了失速先兆的特性,并且与压气机失速实验进行了比较。结果表明,计算与实验的特性线符合较好,单转子三维计算与压气机三级实验中第一级转子在失速先兆和失速团的特性一致。并且数值失速过程中动叶通道内部动态压力的变化与实验结果也很接近。     

一台低速压气机的失速前扰动分析

本文应用小波的方法对一台三级、低速、轴流压气机的动态实验数据进行了分析。所分析的数据点的范围从压气机发生旋转失速前1000转开始,分析结果表明:失速前扰动的出现是间歇性的,即扰动出现、发展、消失、再出现、再发展、再消失。将所有沿圆周方向布置的传感器信号一起分析,失速前扰动形成的团沿圆周方向旋转。而且,越接近失速点,失速前扰动团沿圆周方向传播的距离相对越长。同时,表明结构的不均匀产生在第七传感器和第一传感器之间。     

HYPOCRELLIN-A SENSITIZED PHOTOOXIDATION OF BILIRUBIN

Hypocrellin A (HA) extracted from Hypocrellia bambusae (b.et Br.) sace, a derivative of 3,10-dihydroxy-4,9-perylenequinone, is a highly effective photosensitizer. Kinetic studies of the HA-sensitized photooxidation of bilirubin IX alpha (BR) in different solvents in the presence of various active oxygen quenchers indicate that in aprotic solvents the photooxidation goes via a Type II (1O2) mechanism, whereas in alkaline protic solvents Type I (electron transfer from an excited state of HA to the ground state of oxygen or the BR substrate). Type II and probably free radical reactions may occur simultaneously.     

Photodynamic action of a water-soluble hypocrellin derivative with enhanced absorptivity in the phototherapeutic window II. Photosensitized generation of active oxygen species

Cysteine-substituted hypocrellin B (Cys-HB) is a water-soluble perylenequinonoid derivative with significantly enhanced absorptivity in the range of wavelength longer than 600 nm. Electron paramagnetic resonance (EPR) measurements, quenching experiments and 9,10-diphenyl-anthracene bleaching studies were used to investigate the photodynamic action of Cys-HB in the presence of oxygen. Illumination of Cys-HB solution, in the presence of oxygen, generated singlet oxygen, superoxide anion radical, hydroxyl radical and hydrogen peroxide. The accumulation of active oxygen species was transformed into that of the semiquinone anion radical with the depletion of oxygen, detected by the spin counteraction of TEMPO radical formed via the reaction of TEMP with singlet oxygen produced by Cys-HB photosensitization. Oxygen content, Cys-HB concentration and reaction environment affected the transformation and the competition between the Type I and Type II reactions. Compared with hypocrellin B (HB), Cys-HB primarily remained similar and slightly lower capability of active oxygen-generation, confirmed to be a favorable phototherapeutic agent.