贵金属Cu、Ag、Au的电子结构和物理性质

由纯金属单原子理论(OA)确定了面心立方结构(FCC)贵金属Cu、Ag、Au的电子结构依次为[Ar](3dn)5.58(3dc)4.21(4sc)0.23(4sf)0.98、[Kr](4dn)4.87(4dc)4.56(5sc)0.66(5sf)0.91、[Xe](5dn)4.20(5dc)4.90(6sc)1.57(6sf)0.33,并确定了Cu、Ag、Au的密排六方结构(HCP)和体心立方结构(BCC)两种初态特征晶体和初态液体的电子结构。根据自然态的电子结构定性解释了熔点、拉伸强度、维氏硬度、体弹性模量、电导和热导率物理性质差异与电子结构的关系,定量计算了晶格常数、结合能、势能曲线及线热膨胀系数随温度的变化。根据非自然态的电子结构,定性解释了晶体结构BCC和HCP的关系。     

The distribution of grain boundary planes in polycrystals

During the last ten years, techniques have been developed to measure the distribution of grain boundaries in polycrystals as a function of both lattice misorientation and grain boundary plane orientation. This paper presents a brief overview of the techniques used for these measurements and the principle findings of studies implementing these techniques. The most significant findings are that grain boundary plane distributions are anisotropic, that they are scale invariant during normal grain growth, that the most common grain boundary planes are those with low surface energies, that the grain boundary populations are inversely correlated with the grain boundary energy, and that the coincident site lattice number is a poor predictor of the grain boundary energy and population.     

二层组装四磺酸酞菁铜修饰电极的制备、表征与应用

四磺酸酞菁铜在1，3-二环己基碳二亚胺（DCC）的活化下与自组装膜上的氨基发生表面化学反应，制得了二层组装半胱胺．四磺酸酞菁铜／金电极，将四磺酸酞菁铜固定在金电极表面。利用循环伏安、扫描电镜进行了组装电极的表征。这种二层组装的电极对半胱胺酸具有催化作用。     

关于煤炭硫分分级的探讨

根据国家质量技术监督局的计划安排,国家标准GB／T15224－1994《煤炭质量分级》需要修订。本文主要讨论“煤炭硫分分级”方面的内容。     

Preparation of Protein-Stabilized β-Carotene Nanodispersions by Emulsification–Evaporation Method

This work was initiated to prepare protein-stabilized β-carotene nanodispersions using emulsification–evaporation. A pre-mix of the aqueous phase composed of a protein and hexane containing β-carotene was subjected to high-pressure homogenization using a microfluidizer. Hexane in the resulting emulsion was evaporated under reduced pressures, causing crystallization and precipitation of β-carotene inside the droplets and formation of β-carotene nanoparticles. Sodium caseinate (SC) was the most effective emulsifier among selected proteins in preparing the nanodispersion, with a monomodal β-carotene particle-size distribution and a 17-nm mean particle size. The results were confirmed by transmission-electron microscopy analysis. SC-stabilized nanodispersion also had considerably high ζ-potential (−27 mV at pH 7), suggesting that the nanodispersion was stable against particle aggregation. Increasing the SC concentration decreased the mean particle size and improved the polydispersity of the nanodispersions. Nanodispersions prepared with higher β-carotene concentrations and higher organic-phase ratios resulted in larger β-carotene particles. Although increased microfluidization pressure did not decrease particle size, it did improve the polydispersity of the nanodispersions. Repeating the microfluidization process at 140 MPa caused the nanodispersions to become polydisperse, indicating the loss of emulsifying capacity of SC due to protein denaturation.     

夹层式结构在金刚石钻头上的应用

采用冷压成型夹层和加灰(过渡层)热压烧结法制备了一种夹层结构金刚石钻头.经与普通金刚石钻头进行对比试验发现,夹层结构钻头速度和使用寿命比普通钻头有了明显的提高,其原因是由于钻头工作时岩脊的体积破碎作用.这样初步找到了一种既能提高金刚石钻头钻进速度,又能增加金刚石钻头寿命的制造方法.     

Informational Entropy: a Failure Tolerance and Reliability Surrogate for Water Distribution Networks

Evolutionary algorithms are used widely in optimization studies on water distribution networks. The optimization algorithms use simulation models that analyse the networks under various operating conditions. The solution process typically involves cost minimization along with reliability constraints that ensure reasonably satisfactory performance under abnormal operating conditions also. Flow entropy has been employed previously as a surrogate reliability measure. While a body of work exists for a single operating condition under steady state conditions, the effectiveness of flow entropy for systems with multiple operating conditions has received very little attention. This paper describes a multi-objective genetic algorithm that maximizes the flow entropy under multiple operating conditions for any given network. The new methodology proposed is consistent with the maximum entropy formalism that requires active consideration of all the relevant information. Furthermore, an alternative but equivalent flow entropy model that emphasizes the relative uniformity of the nodal demands is described. The flow entropy of water distribution networks under multiple operating conditions is discussed with reference to the joint entropy of multiple probability spaces, which provides the theoretical foundation for the optimization methodology proposed. Besides the rationale, results are included that show that the most robust or failure-tolerant solutions are achieved by maximizing the sum of the entropies.     

Use of cascade reduction potential for selective precipitation of Au,Cu, and Pb in hydrochloric acid solution

Optimization of reduction potential for electroseparation was studied for the recovery of gold, copper, and lead from acidic solution. A linear sweep voltammetric method enabled us to determine characteristic reduction potentials for each metal and the kinetics of the metal deposition indicated by current-voltage curves. In order to precipitate the metal species sequentially, reduction potentials were examined for the individual and mixed solutions of Au(III), Cu(II), and Pb(II). The three metals were reasonably well isolated from the mixed solutions such as Cu(II)/ Pb(II) and Au(III)/Cu(II)/Pb(II) in the order of the corresponding reduction potentials, in particular, the mass transfer controlled reduction potentials, obtained from linear sweep voltammetry (LSV) measurement.