江西某复杂难选铅锌矿石工艺矿物学研究

采用矿物参数自动检测仪、扫描电子显微镜等对铅锌矿石的进行工艺矿物学研究。结果表明,矿石主要金属矿物以闪锌矿、方铅矿、黄铁矿等硫化物为主,脉石矿物以碳酸盐岩为主,矿物成分复杂增加了有价金属分离难度;矿石主要有用元素为铅、锌,含量分别为1.98%、3.27%,其中方铅矿中的铅占74.26%,闪锌矿中的锌占64.75%,金、银含量分别为0.3 g/t和73.5 g/t,矿石经济价值高;方铅矿、闪锌矿及黄铁矿嵌布粒度非常细,整体属于中细粒级范畴;-0.074 mm占21.45％条件下的原矿中,方铅矿、闪锌矿的解离度分别为54.8%和57.8%,连生关系复杂。根据不同磨矿细度下的解离度分析结果,建议采用的磨矿细度为-0.074 mm占83%,在该细度条件下,方铅矿和闪锌矿能够解离充分,解离度分别为83.1%和85.5%。根据该类型矿石的工艺矿物学特性,本文建议采用“依次浮选铅—锌—硫”的优先浮选工艺流程,依次得到铅、锌、硫精矿。     

Acid‐Base and Organic‐Water Distribution Equilibria for Symmetrically‐Substituted P,P′‐Dialkyl Alkylenebisphosphonic Acids

Abstract

P,P′‐dialkyl alkylenebisphosphonic acids are powerful metal extraction reagents. The acid dissociation constants for a homologous series of aqueous‐insoluble P,P′‐di‐3‐(trimethylsilyl)‐propyl and aqueous‐soluble P,P′‐diethyl methylene‐, ethylene‐ and propylene‐ bisphosphonic acids were determined in a 70∶30 w/w methanol‐water solvent by potentiometric titration and ³¹P NMR spectrometry. The values obtained for the diethyl‐substituted acids were compared with those determined in water and used to assess the effect of the medium on the aqueous acid dissociation constants of the lipophilic series of P,P′‐di‐3‐(trimethylsilyl)propyl alkylenebisphosphonic acids. The dependence of the organic/aqueous distribution equilibrium on the aqueous acid concentration was also investigated using electrospray ionization mass spectrometry. The acid dissociation and organic/aqueous distribution properties of the substituted alkylenebisphosphonic acids are discussed in terms of their influence on metal ion extraction.     

带电粒子对FOX-7裂解通道影响的密度泛函研究

为研究带电粒子(H_3O~+,OH~-,NO_2~+ and NO~+)对1,1-二氨基-2,2-二硝基乙烯(FOX-7)裂解通道的影响,采用密度泛函理论的B3LYP、B3PW91和PBE0泛函理论在6-31++G(d,p)基组下优化出了H_3O~+,OH~-,NO_2~+ 和 NO~+分别与FOX-7的复合体,从成键方式和静电势变化的角度分析了复合方式。在相同水平下,计算了各复合体不同裂解通道的活化能,并基于键长、键级、成键方式等电子结构参数的变化分析了活化能变化的本质。结果表明,在B3LYP/6-31++G(d,p)水平上,OH~-使两种构型C—NH_2键的离解能分别下降了260.7 k J·mol-1和74.3 k J·mol-1,H_3O~+,NO_2~+ 和 NO~+使C—NO_2键的离解能下降44~260 k J·mol-1,带电粒子使大部分复合体C—C键的离解能提高,但对硝基异构的活化能影响甚微,由过渡态分析可知,这源于硝基异构的过渡态具有的极其相似的几何构型。四种带电粒子都扰乱了单分子FOX-7相对稳定的结构,降低了FOX-7后续裂解的能垒,影响了FOX-7裂解中后期自加速反应的进程。     

X射线衍射分析聚乙烯吡咯烷酮对水合物分解过程的影响

深水油气资源的勘探开发以及开采过程中的环保要求,使得天然气水合物动力学抑制剂使用不可避免,含动力学抑制剂的分解研究对水合物生成后的解堵具有重要的指导意义。本文在高压反应釜内采用甲烷和丙烷混合气,合成天然气水合物,并用X射线粉晶衍射仪分析了含动力学抑制剂聚乙烯吡咯烷酮的水合物分解过程。结果显示甲烷和丙烷气体会形成SⅡ型水合物,但伴随有SⅠ型甲烷水合物的生成;添加动力学抑制剂后,水合物的分解速率变慢,在-60℃,添加0.5%的聚乙烯吡咯烷酮后,分解起始的20 min内,无抑制剂体系水合物分解可达69%,而在含抑制剂体系分解约18%;SⅡ型甲烷丙烷混合气水合物分解过程中晶胞各晶面分解速率相同,没有偏好性,水合物笼作为一个整体分解,添加抑制剂不改变这种分解方式,仍以整体分解。     

分子内氢键对屏蔽酚抗氧化活性的影响

采用基于密度泛函理论的量子化学从头算法计算了不同分子结构屏蔽酚的O-H键解离能(E_BD),采用压力差示扫描量热仪测定了屏蔽酚在润滑油基础油中的抗氧化活性,考察了屏蔽酚的E_BD与其抗氧化活性之间的关系,并重点探究了结构因素对邻位桥联屏蔽双酚E_BD的影响。结果表明,屏蔽酚的活性构象E_BD越小,其抗氧化活性越高。分子内氢键对邻位桥联屏蔽双酚的E_BD可以产生显著影响。对于邻位桥联屏蔽双酚分子而言,其最低能量构象存在2个O-H┅π氢键,E_BD较高,并非抗氧化活性构象;存在1个O-H┅O氢键的局部最低能量构象,E_BD相对较低,为抗氧化活性构象。邻位亚甲基桥联屏蔽双酚分子的内旋转能垒较低,容易形成E_BD较低的活性构象,这是其抗氧化效果突出的主要原因。     

Electronic Structure and Geminate Pair Energetics at Organic–Organic Interfaces: The Case of Pentacene/C60 Heterojunctions

Organic semiconductors are characterized by localized states whose energies are predominantly determined by electrostatic interactions with their immediate molecular environment. As a result, the details of the energy landscape at heterojunctions between different organic semiconductors cannot simply be deduced from those of the individual semiconductors, and they have so far remained largely unexplored. Here, microelectrostatic computations are performed to clarify the nature of the electronic structure and geminate pair energetics at the pentacene/C₆₀ interface, as archetype for an interface between a donor molecule and a fullerene electron acceptor. The size and orientation of the molecular quadrupole moments, determined by material choice, crystal orientation, and thermodynamic growth parameters of the semiconductors, dominate the interface energetics. Not only do quadrupoles produce direct electrostatic interactions with charge carriers, but, in addition, the discontinuity of the quadrupole field at the interface induces permanent interface dipoles. That discontinuity is particularly striking for an interface with C₆₀ molecules, which by virtue of their symmetry possess no quadrupole. Consequently, at a pentacene/C₆₀ interface, both the vacuum‐level shift and geminate pair dissociation critically depend on the orientation of the pentacene π‐system relative to the adjacent C₆₀.     

Dissociations of the night: Individual differences in sleep-related experiences and their relation to dissociation and schizotypy.

The author examined the associations among sleep-related experiences (e.g., hypnagogic hallucinations, nightmares, waking dreams, and lucid-dreams), dissociation, schizotypy, and the Big Five personality traits in 2 large student samples. Confirmatory factor analyses indicated that (a) dissociation and schizotypy are strongly correlated—yet distinguishable—constructs, and (b) the differentiation between them can be enhanced by eliminating detachment/depersonalization items from the dissociation scales. A general measure of sleep experiences was substantially correlated with both schizotypy and dissociation (especially the latter) and more weakly related to the Big Five. In contrast, an index of lucid dreaming was weakly related to all of these other scales. These results suggest that measures of dissociation, schizotypy, and sleep-related experiences all define a common domain characterized by unusual cognitions and perceptions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

390.60nm激光作用下Si(CH3)4的多光子解离与硅原子的(1+1)电离

在390.60nm的紫外激光作用下，利用超声分子束技术与飞行时间（TOF）质谱仪相结合的方法研究了气相四甲基硅分子多光子电离（MPI）的TOF质谱，在较低能量的激光作用下主要检测到了Si(CH3)^ 、Si^ 、C2^ 等离子的信号，有时甚至只检测到了Si^ 离子的信号：在较高能量的激光作用下主要检测到Si(CH3)^ n(n=1,2,3,4)、Si^ 、C2^ 甚至还有SiC3^ ,SiC2^ 等离子的信号。据此并结合以前得到的结论，讨论了四甲基硅分子可能的MPI过程。得出了Si^ 主要来自于Si(CH3)4的多光子解离－Si原子的（1＋1）电离、Si(CH3)n^ (n=1,2,3)的（3＋1）电离、Si(CH3)^ 4来自于Si(CH3)4的（3＋1）电离的结论。     

Judgment dissociation theory: An analysis of differences in causal, counterfactual and covariational reasoning.

Research suggests that causal judgment is influenced primarily by counterfactual or covariational reasoning. In contrast, the author of this article develops judgment dissociation theory (JDT), which predicts that these types of reasoning differ in function and can lead to divergent judgments. The actuality principle proposes that causal selections focus on antecedents that are sufficient to generate the actual outcome. The substitution principle proposes that ad hoc categorization plays a key role in counterfactual and covariational reasoning such that counterfactual selections focus on antecedents that would have been sufficient to prevent the outcome or something like it and covariational selections focus on antecedents that yield the largest increase in the probability of the outcome or something like it. The findings of 4 experiments support JDT but not the competing counterfactual and covariational accounts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of the filament temperature on the structure of hot-wire deposited silicon

Exposure to hydrogen significantly cools the filament from the set temperature. This can mainly be explained by the power dissipation due to dissociation of hydrogen. The effect of silane on the filament temperature is more complicated. Below a certain threshold temperature (1850 K for W, 1750 K for Ta) a silicon-rich silicide is deposited on the filament, partially shielding it for further dissociation reactions. A drop in deposition rate accompanies this. Above another but higher threshold temperature (2000 K for W and 1950 K for Ta) the silicon-rich silicide is evaporated from the filament and the dissociation reactions occurred and thus the deposition rate are restored. Below these threshold temperatures (2 2 0) oriented materials can be produced.