Mössbauer Spectroscopy on Nuclear Power Plant Materials

Experimental results of original irradiated reactor pressure vessel surveillance specimens are presented and discussed in the paper. In 1994, the new Extended Surveillance Specimen Program for Nuclear Reactor Material Study was started in collaboration with the nuclear power plant (NPP) Bohunice and NPP Research Institute Trnava (Slovakia). Three batches of special prepared Mössbauer samples (after 1, 2 and 3 years stay in irradiation channels) were measured and interpreted using the new four components approach of Mössbauer spectra evaluation with the aim to observe microstructural changes due to thermal and neutron treatment resulting from operating conditions in NPP. The systematic changes in the relative areas of Mössbauer spectra components were observed and discussed.     

水解聚丙烯酰胺分子量的表征

在 2 5℃、0 .5mol/LNaCl水溶液中 ,测定了 40种水解聚丙烯酰胺样品的特性粘数 ,求出了Mark -Houwink方程常数K、α值。在水解度 2～ 40 %之间 ,发现K、α对水解度具有强烈的依赖性 ,并且特征粘数与水解度的平方根成直线关系。利用本文所求的 K、α值预测本研究的水解聚丙烯酰胺样品分子量 ,其误差在± 8%之间 ;而对文献数据进行处理 ,其平均误差为 11.12 %。     

THE RELATION BETWEEN STRENGTH AND RIGIDITY OF BEAM1)

本文提出了梁的强刚比的定义,用无量纲的形式定量地表达了梁的强度与刚度之间的关系,以期充分发挥材料的潜力并促进材料力学的课堂教学。强刚比与载荷大小无关,其数值可以通过有限元方法或者通过梁的载荷试验来获得。结合工程实际,从设计和试验两个方面对梁的强刚比 及其影响因素进行了简要地探讨和分析。     

Information Theories with Adversaries,Intrinsic Information,and Entanglement

There are aspects of privacy theory that are analogous to quantum theory. In particular one can define distillable key and key cost in parallel to distillable entanglement and entanglement cost. We present here classical privacy theory as a particular case of information theory with adversaries, where similar general laws hold as in entanglement theory. We place the result of Renner and Wolf—that intrinsic information is lower bound for key cost—into this general formalism. Then we show that the question of whether intrinsic information is equal to key cost is equivalent to the question of whether Alice and Bob can create a distribution product with Eve using I_M bits of secret key. We also propose a natural analogue of relative entropy of entanglement in privacy theory and show that it is equal to the intrinsic information. We also provide a formula analogous to the entanglement of formation for classical distributions. It is our pleasure to dedicate this paper to Asher Peres on the occasion of his seventieth birthday.     

External Fields, Density Functionals, and the Gibbs Inequality

By combining the upper and lower bounds to the free energy as given by the Gibbs inequality for two systems with the same intermolecular interactions but with external fields differing from each other only in a finite region of space , we show that the corresponding equilibrium densities must also differ from each other somewhere in . We note that the basic equations of density functional theory arise naturally from a simple rearrangement and reinterpretation of the terms in the upper bound Gibbs inequality for such systems and briefly discuss some of the complications that occur when the intermolecular interactions of the two systems also differ.     

响应面方法计算HTR-10余热排出系统物理过程的失效概率

在核电站安全研究中，概率安全评价方法已经得到了广泛的应用.但是对于采用非能动设计的核电站系统，其可靠性分析的研究还处于初级阶段.非能动系统的失效不但要考虑常规可靠性分析中考虑的设备失效，还要考虑物理过程的失效.物理过程失效概率的计算方法和能动系统可靠性分析方法完全不同.本文给出物理过程失效的数学描述，介绍了一次二阶矩法、响应面方法，并且应用响应面方法计算了清华大学核能技术设计研究院10MW高温气冷实验堆(HTR-10)余热排出系统失效概率的近似值. 关键词： 概率安全评价 非能动系统 可靠性 响应面     

大气消光特性与机载激光雷达眼睛安全关系的研究

依据美国ANSI标准，定量分析了气溶胶、卷云和沙尘的垂直消光特性对机载激光雷达激光脉冲眼睛安全最大阈值能量的影响；以地基激光雷达探测得到的合肥上空沙尘暴为例，定量给出了大气中各成分消光特性对飞机眼睛安全最低高度的影响；模拟计算了各种大气成分的消光特性对激光脉冲眼睛安全系数的影响随高度的变化规律。计算结果表明：沙尘层对激光脉冲眼睛安全最大阈值能量的影响幅度可达几十毫焦。该结果为我国第一台机载大气探测激光雷达激光脉冲能量设置提供了基本依据。     

XPS investigations of ruthenium deposited onto representative inner surfaces of nuclear reactor containment buildings

In the case of a hypothetical severe accident in a nuclear power plant, interactions of gaseous RuO₄ with reactor containment building surfaces (stainless steel and epoxy paint) could possibly lead to a black Ru-containing deposit on these surfaces. Some scenarios include the possibility of formation of highly radiotoxic RuO₄(g) by the interactions of these deposits with the oxidizing medium induced by air radiolysis, in the reactor containment building, and consequently dispersion of this species. Therefore, the accurate determination of the chemical nature of ruthenium in the deposits is of the high importance for safety studies. An experiment was designed to model the interactions of RuO₄(g) with samples of stainless steel and of steel covered with epoxy paint. Then, these deposits have been carefully characterised by scanning electron microscopy (SEM/EDS), electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). The analysis by XPS of Ru deposits formed by interaction of RuO₄(g), revealed that the ruthenium is likely to be in the IV oxidation state, as the shapes of the Ru 3d core levels are very similar with those observed on the RuO₂·xH₂O reference powder sample. The analysis of O 1s peaks indicates a large component attributed to the hydroxyl functional groups. From these results, it was concluded that Ru was present on the surface of the deposits as an oxyhydroxide of Ru(IV). It has also to be pointed out that the presence of “pure” RuO₂, or of a thin layer of RuO₃ or Ru₂O₅, coming from the decomposition of RuO₄ on the surface of samples of stainless steel and epoxy paint, could be ruled out. These findings will be used for further investigations of the possible revolatilisation phenomena induced by ozone.     

Polystyrene/decahydronaphthalene/propane phase equilibria and polymer conformation properties from intrinsic viscosities

The influence of dissolved propane (up to 31.2 wt %) on the phase equilibria of 5 wt % polystyrene (PS) dissolved in 66/34 wt % trans/cis‐decahydronaphthalene (DHN) was measured over the temperature range of 323–423 K. A suitable temperature, pressure, and propane composition operating space was defined to measure intrinsic viscosities of a single fluid phase. Intrinsic viscosities of PS in cosolvent mixtures of propane and trans/cis‐DHN were measured between 323 and 423 K and between 70 and 208 bar. The addition of propane to the isomeric mixture of DHN resulted in a decreased solvent quality for PS, causing a contraction of the PS coil. The most dramatic decrease in solvent quality with the addition of propane occurred at 323 K and 70 bar with approximately a 36% reduction in the viscometric radius with the addition of 45 mol % propane to DHN. At 423 K, the solvent quality was less sensitive to the addition of propane and only a 13% reduction in the viscometric radius was observed at 70 bar and 45 mol % propane in DHN. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Applications of Fruit Polyphenols and Their Functionalized Nanoparticles Against Foodborne Bacteria: A Mini Review

The ingestion of contaminated water and food is known to cause food illness. Moreover, on assessing the patients suffering from foodborne disease has revealed the role of microbes in such diseases. Concerning which different methods have been developed for protecting food from microbes, the treatment of food with chemicals has been reported to exhibit an unwanted organoleptic effect while also affecting the nutritional value of food. Owing to these challenges, the demand for natural food preservatives has substantially increased. Therefore, the interest of researchers and food industries has shifted towards fruit polyphenols as potent inhibitors of foodborne bacteria. Recently, numerous fruit polyphenols have been acclaimed for their ability to avert toxin production and biofilm formation. Furthermore, various studies have recommended using fruit polyphenols solely or in combination with chemical disinfectants and food preservatives. Currently, different nanoparticles have been synthesized using fruit polyphenols to curb the growth of pathogenic microbes. Hence, this review intends to summarize the current knowledge about fruit polyphenols as antibacterial agents against foodborne pathogens. Additionally, the application of different fruit extracts in synthesizing functionalized nanoparticles has also been discussed.