Pure spin-current diode based on interacting quantum dot tunneling junction

A magnetic field-controlled spin-current diode is theoretically proposed, which consists of a junction with an interacting quantum dot sandwiched between a pair of nonmagnetic electrodes. By applying a spin bias V_S across the junction, a pure spin current can be obtained in a certain gate voltage regime,regardless of whether the Coulomb repulsion energy exists. More interestingly, if we applied an external magnetic field on the quantum dot, we observed a clear asymmetry in the spectrum of spin current I_S as a function of spin bias, while the charge current always decays to zero in the Coulomb blockade regime. Such asymmetry in the current profile suggests a spin diode-like behavior with respect to the spin bias, while the net charge through the device is almost zero. Different from the traditional charge current diode, this design can change the polarity direction and rectifying ability by adjusting the external magnetic field, which is very convenient. This device scheme can be compatible with current technologies and has potential applications in spintronics or quantum processing.     

Entropy product measure for multipartite pure states

An entanglement measure for multipartite pure states is formulated using the product of the von Neumann entropy of the reduced density matrices of the constituents. Based on this new measure, all possible ways of the maximal entanglement of the triqubit pure states are studied in detail and all types of the maximal entanglement have been compared with the result of ‘the average entropy’. The new measure can be used to calculate the degree of entanglement, and an improvement is given in the area near the zero entropy.     

General Solution for the Complete Separability of a Pure Quantum State with Real Coefficients for a Quantum Network of Any Nodes

By means of the criterion of entanglement in terms of the covariance correlation tensor in quantum network theory, this article discusses the generalsolution for the complete separability of the pure quantum state with real coefficients for a quantum network of any nodes.     

咪唑离子液体键合硅胶固定相纯水洗脱分离碱基、酚类和药物化合物

采用N-甲基咪唑和氯丙基咪唑反应的方法制备得到了离子液体键合硅胶固定相,并利用该固定相中的咪唑环阳离子和被分析物之间存在的多重作用机理如疏水作用、静电吸引和排斥及氢键作用等,以纯水作为流动相,成功地分离了碱基(胞嘧啶、胸腺嘧啶、2-氨基嘧啶和6-氯鸟嘌呤)、酚类化合物(间氨基酚、间苯二酚和间硝基酚)以及3种药物化合物(盐酸吗啉呱、阿昔洛韦和头孢氨苄)。采用没有添加任何有机溶剂和缓冲液的纯水作流动相,既绿色环保,又节约经济,简单方便。对该固定相分离这些化合物的保留机理做了探讨。     

聚乙二醇对聚醚砜超滤膜微结构和性能的影响

通过改变铸膜液中添加剂PEG的含量，测试了当铸膜液中PES的质量分数为0．21，凝固浴(DM—SO／H2O体系)中DMSO的质量分数为0．10时，所成膜的水通量和尿素、肌酐去除率。研究了PES／DMSO体系中小分子添加剂PEG作用的规律。     

Monitoring Conformational Changes in an Enzyme Conversion Inhibitor Using Pure Shift Exchange NMR Spectroscopy

We report the acquisition of 2D NMR EXSY spectra with ultrahigh resolution, which allows for probing the slow conformational exchange process in a pharmaceutical compound. The resolution enhancement is achieved by implementing interferogram based PSYCHE homonuclear decoupling to generate a pure shift proton spectrum along the direct domain of the resulting data. The performance of this pure shift EXSY pulse sequence is compared to the standard experiment recorded under identical conditions. It is found that although being less sensitive and requiring a longer acquisition time, the quality of pure shift spectra allows for extracting exchange rates values that are coherent with the ones determined by standard approach, on a temperature range that demonstrates the robustness of the chosen homonuclear decoupling method. The resolution enhancement provided by the simplification of proton line shape allows for probing a higher number of proton sites whose analysis would have been biased using a standard method. These results open the way to a thorough and accurate study of chemical exchange processes based on a multi-site analysis of 2D pure shift EXSY spectra     

铝阳极氧化膜的半导体特性

The semiconductor properties of anodic oxide film formed on commercial pure aluminum were analyzed usingMott-Schottky theory and point defect model (PDM). The donor density, oxygen vacancy diffusion coefficient and flat-band potential were measured for the oxide films sealed by boiling water and K2Cr2O7, respectively. The results indicated that the anodic oxide films showed the n-type semiconductor property and the donor density decreased exponentially with the voltage elevating. The value of oxygen vacancy diffusion coefficient is about (1.12-5.53)伊10-14 cm-2·s-1. The flat-band potential of anodic oxide filmdeclined after sealing.     

定向含硼MFI型沸石膜对纯气体的渗透性以及对乙醇/水体系的分离选择性

研究定向含硼MFI型沸石膜和原多孔玻璃基材对纯气体的渗透性以及对乙醇/水体系的分离选择性.原多孔玻璃基材对纯气体的透过表现出诺森扩散选择性,表明气体以诺森扩散通过.纯气体透过焙烧后的B-A1-ZSM-5沸石膜,H₂,He,Ne,Ar,O₂,CO₂对N₂的理想选择性分别为16.8,15.6,12.6,9.41,8.60,5.32;CO和SO₂对N₂的理想选择性分别为0.135和0.0179;O₂对CO和SO₂的理想选择性分别为63.7和480.2.这表明该类沸石膜对纯气体的透过不仅具有良好的理想选择性,而且可能为新型防毒面具提供一种很好的可选材料.渗透汽化实验表明,在测定温度范围内原多孔玻璃基材对三种不同浓度的乙醇/水体系几乎没有分离性能.焙烧后的B-A1-ZSM-5沸石膜对5 wt%,50wt%和95wt%乙醇/水体系的分离,水的最大分离系数分别为28.2,135.7和518.5,且温度均为303 K.表明该MFI型沸石膜具有强的亲水性.     

Prediction of the enthalpy of vapourisation for anhydrides,formates, acetates,propionates, butyrates,esters, and ethers

Four analytical correlations based on the use of the corresponding states principle were used to calculate the enthalpy of vapourisation of fluids. Three of these correlations require as inputs the critical temperature and the acentric factor. The fourth requires a molecular Lennard–Jones parameter and the acentric factor. Results for 184 polar and non-polar fluids grouped into 9 families are compared with the values accepted by the Design Institute for Physical Property (DIPPR) project. Recommendations are given for the use of each model and for the choice of the adequate model for each family of fluids.     

Aminoalkohole, 2. Mitt.: Ein Verfahren zur Herstellung enantiomerenreiner pharmakologisch aktiver β-Aminoalkohole

Zusammenfassung Die Reduktion enantiomerenreiner O-MBF- bzw. O-MBE-geschützter Cyanhydrine mit LiAlH₄ führt unter Einhaltung definierter Reaktionsbedingungen zu den entsprechenden geschützten Aminoalkoholen, in denen der Anteil der durch Epimerisierung gebildeten Nebenprodukte kleiner als 3% ist. Die Abtrennung der unerwünschten Diastereomere erfolgt im Zuge der Reinigung der Produkte. Durch Schutzgruppenabspaltung mit Salzsäure/Methanol können die enantiomerenreinen Aminoalkohole erhalten werden. Die meist sehr guten Trennfaktoren der O-MBF- bzw. O-MBE-geschützten Verbindungen erlauben für viele Verbindungen sowohl im Cyanhydrin- als auch im Aminoalkoholstadium eine präparative Trennung und machen das Verfahren deshalb vielseitig verwendbar.

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Aminoalcohols II: Preparation of enantiomerically pure pharmacologically active -aminoalcohols

Summary A synthesis of -aminoalcohols is described starting from racemic or enantiomerically pure -hydroxynitriles which were O-protected using enantiomerically pure acetal type protective groups. Reduction with lithium aluminium hydride yielded O-protected -aminoalcohols. Whenever diastereomeric O-protected cyanohydrins could not be separated, the mixture was reduced and the resulting O-protected aminoalcohols were separated. Removal of the protective group using hydrogen chloride and methanol yielded enantiomerically pure -aminoalcohols or their corresponding hydrochlorides.

Herrn Prof. Dr.F. Eiden zum 70. Geburtstag gewidmet