Synthesis and Characterization of Process Related Impurities of (±)‐Milnacipran

Milnacipran is a cyclopropane derivative, used as an anti depressant drug. During the process development of milnacipran, four process related potential impurities were detected in high performance liquid chromatography. All these impurities were identified, synthesized and subsequently characterized by their respective spectral data (IR, LC‐MS, ¹H NMR, and ¹³C NMR) as described in this article.     

ICP-AES法测定铅精矿中的杂质元素

用HNO3-KClO3-H2SO4溶样,采用ICP-AES测定铅精矿中的杂质元素。并试验了酸度、共存元素对测定的影响,方法的精密度、检出限及回收率均能满足要求。     

Interactive effect of impurities on giant magnetoresistance of Co–Fe/Cu multilayers

Giant magnetoresistance of Co–Fe–B/Cu multilayers fabricated in the sputtering atmosphere, where the amount of oxygen impurity is varied, is discussed in connection with their interfacial roughness. The magnetoresistance (MR) ratio of Co–Fe/Cu multilayers is enhanced by up to 33% when the oxygen content is varied between 10 and 100 ppm of processing Ar gas. The enhancement of the MR ratio was due to the flattening effect of impurity oxygen on the multilayer interfaces: the root mean square roughness of the multilayer was decreased from 7.5 to 5 Å. With increasing boron content in Co–Fe layers, however, the enhancing effect of MR ratio by oxygen diminished and nearly vanished for 12 at%-B–(Co–Fe) case. The strong affinity of boron for oxygen is suggested as a probable mechanism.     

电感耦合等离子体质谱法测定高纯氧化钕中稀土杂质的研究

本文报导了高纯氧化钕中Ｙ、Ｌａ、Ｃｅ、Ｐｒ、Ｓｍ、Ｅｕ、Ｇｄ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ等１１中稀土杂质的电感耦合等离子体质谱测定方法。选择了仪器最佳操作参数，研究了质谱干扰和基体效应，采用Ｔ１内标可基本克服基体效应。方法检出限为０．０１９－０．０９５ｎｇ／ｍＬ，加标回收率为８１．８％－１０３．３％。     

Impurity doping into Mg2Sn: A first-principles study

We studied the formation energy and atomic structure of impurities in Mg₂Sn using first-principles plane-wave total energy calculations. Twenty elements, namely H, Li, Na, K, Rb, Sc, Y, La, Cu, Ag, Au, B, Al, Ga, In, N, P, As, Sb, and Bi, were selected as the impurity species. We considered structural relaxation of the atoms within the second nearest neighbors of the impurity atom in the 48-atom supercell. The results of the formation energy calculations suggested that Sc, Y, La, P, As, Sb, and Bi are good n-type dopants whereas Li and Na are good p-type dopants. The electrical properties of Li-, Na-, and Ga-doped Mg₂Sn and La-doped Mg₂(Si, Sn) composites reported previously can be explained by the low formation energies of Li, Na, Ga, and La in Mg₂Sn.     

杂质对KDP晶体光学质量的影响

 研究了几类可能出现在KDP晶体的生长溶液中的有机物杂质和无机阴离子杂质基团对KDP晶体散射、透过率、光损伤阈值等光学质量的影响，结果表明，不同种类的杂质的影响并不相同，造成这一结果的根本原因在于杂质离子的结构及其与晶体表面原子成键能力的不同。     

Transport properties of surface acoustic wave based single electron transport device in the presence of an impurity potential

We report the transport properties of a surface acoustic wave based single electron transport device, which contains an unintentional quantum dot induced by background impurity potential fluctuations. It is found that the presence of the impurity potential can cause a deviation of the acoustoelectric current from its quantized value. Through the charging effect of the quantum dot induced by the impurity, we get an approximate relationship between the applied gate voltage and its corresponding electrostatic potential barrier height, together with the Coulomb charging energy needed to add a second electron into the dynamic quantum dot. Moreover, the amplitude of the surface acoustic wave is also estimated within a simple model.     

Impurity proton NMR signals from common "proton-free" laboratory materials

For the study of small samples (tens of microns cubed) by NMR, impurities from the environment and construction materials (Teflon, Kel-F, glass NMR tubes, etc.) can dominate the signal, in particular for proton NMR. Using pulsed NMR with a resolution of several microseconds, we have studied a number of common construction materials considered to be proton-free and find considerable proton impurity. We present results in terms of impurity proton spins per milligram and discuss procedures to minimize the effects of impurity signal.     

Binding of3He atoms to liquid helium

Summary We calculate the³He−⁴He chemical potential and change in volume in bulk liquid⁴He employing integral equation and Monte Carlo procedures. Detailed numerical results on these quantities and their dependence on bulk density and on the isotopic-mass difference are presented and discussed. This work has been supported by the Deutsche Forschungsgemeinschaft under grant Ri 267 and by the U.S. Department of energy under contract DE-AC 02-76 ER03077 and by the NSF under grant DMR-77-18329.     

ICP-AES用于硅溶胶中杂质元素的直接测定

通过直接称取适量硅溶胶样品稀释于水中,采用超声配制成悬浮液,无需加入额外的分散剂,然后直接进样进行ICP-AES分析,将所获得的结果与传统的样品处理方法所获得的测定结果进行比较,发现两种不同样品处理方法得到的分析结果相一致。该方法无需消解样品,避免了腐蚀性酸的使用,降低了对环境的危害,同时减少了预处理过程。方法的回收率在92%—103%之间,且具有良好的准确度和精密度。