分离富集-原子吸收光谱法测定锌锰电池中铅和镉

对用原子吸收光谱法测定锌锰电池中铅和镉结果的可靠性进行了研究。对于典型的4R25电池,试液中主要成分锌和锰总量超过40 g.L-1,直接用普通稀释法得不到准确的结果。采用CL-7301萃淋树脂微色谱柱将电池试液中铅和镉与基体快速分离,用火焰原子吸收光谱法测定铅和镉,当铅和镉的含量较高时,可以将样品预稀释后采用在线稀释技术直接测定铅和镉。     

酚醛树脂热裂解碳阳极的不可逆容量损失

用酚醛树脂热裂解得到的无序碳为阳极研究了在第一次循环时不可逆容量损失的原因。实验结果表明，不可逆容量损失是由于溶剂分解产生了Li2CO3和在碳表面上形成了含-COO^-基和C-H基的化合物以及在碳主体上形成了含-OLi,-CLi化合物所致。     

非绝对模糊积分,绝对可积性与积分的绝对值不等式

关于模糊数值函数的绝对可积性及对应的积分不等式,无论在何种绝对值意义下是值得讨论的. 本文借助于模糊数空间到具体的 Banach 空间上的嵌入定理和模糊非绝对积分的刻划定理, 讨论了模糊数值函数的绝对可积性及对应的积分不等式,得到了若干个充分必要条件, 并举出了一些反例.     

基于灾变灰预测的企业雇员离职预警模型研究

企业经营过程中,雇员离职是一种正常现象,但某些年份的非正常离职则往往会给企业带来不必要的麻烦和损失,能否对这种非正常离职进行有效预警就显得十分重要.针对这一课题,构建了一个基于灾变灰预测原理的雇员离职预警模型,并结合实例检验了利用该模型进行离职预警的可行性与有效性.     

K-Drop凸空间与局部K-Drop凸空间

引入了Banach空间的局部k-drop凸性质，研究了k-drop凸与局部k-drop凸的一些性质以及两者之间的关系，并用单位球的切片统一而简洁地处理了这两个性质．     

求解P_*(κ)-阵线性互补问题的高阶仿射尺度内点算法

对P*(k)-阵线性互补问题提出了一种高阶内点算法.算法的每步迭代是基于线性规划原始-对偶仿射尺度算法的思想来确定迭代方向,再通过适当选取步长,得到算法的多项式复杂性.     

INHOMOGENEOUS FLUCTUATION DISTRIBUTION IN THE OUTPUT OF STOCHASTIC RESONANCE SYSTEMS AND ITS APPLICATION

Inputting a periodic signal mixed with white noise into a bistable system, we find that the fluctuation distribution in the time series of the output is strongly inhomogeneous. In certain phase part fluctuation is very low under the stochastic resonance condition, and consequently, the signal-to-noise ratio (SNR) there is much higher than that of the input. This mechanism can be used to design a nonlinear receiver to extract the signed from noise with SNR three times higher than the largest SNR obtained so far by the optimal linear filter.     

无溶剂固相研磨法合成乙酰丙酮铝

以无机铝盐、乙酰丙酮(Hacac)为原料,固体碱为反应促进剂,室温下固相研磨合成了乙酰丙酮铝.考察了碱的用量及种类、物料摩尔比、研磨时间对产率的影响,并和经典方法作了对比,固相研磨法产率较高(90%以上).目标产物用红外、热重进行了表征,结果与标准谱图一致.最佳工艺条件为n(A l3+)∶n(Hacac)=10∶40,固体碱适量,室温研磨1 h.     

Copper-Catalyzed Enantioselective Synthesis of α-Hydroxyamine Using Monodentate Phosphoramidites

Development of new methods for the introduction of a nitrogen atom to a carbonyl group is still the most important synthetic target. Cu-catalyzed addition of organozinc reagents to α,β-unsaturated carbonyl compounds has been the subject of intensive investigation.[1] Moreover, trapping of the intermediate Zn-enolates has been achieved using nitrosobenzene. To demonstrate the feasibility of developing enantioselective variants of these tandem C-C bond formations,α,β-unsaturated substrates a～d was subjected to standard reaction conditions using Feringa's (L1*, L2*) and our own phosphoramidite ligands (L3*, L4*). In this reaction, medium to high levels of enantioselectivities were observed.     

Synthesis and Antibacterial Activity of Novel Oxazolidinone Analogs Containing Substituted Thiazole/Fused-Bicyclic Groups

IntroductionOxazolidinones, exemplified by linezolid, are anovel class of totally synthetic antibacterial agents withactivities against a variety of clinically important sus-ceptible and resistant Gram-positive pathogenic bacteriasuch as methicillin-resis…