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991.
The preparation of composite charge-mosaic membrane included spinning of hollow fiber as the supporting membrane, preparing a selective layer on the inside surface of the fiber by interracial polymerization. The charge-mosaic membranes show a high salt permeability while retaining sucrose. The charge-mosaic membrane can be effectively used to separate multivalent salts with organic matter of molecular weight great than 300g/mol in industry.  相似文献   
992.
1. INTRODUCTIONIn the purification process of food, drug, and biological products, usually the material to be purified were not neutral. Application of traditional neutralization method with acid or alkali could increase electrolyte content in the material to be purified. Due to the capability of the adsorption of free alkali by subacid resin, the defect of electrolyte absorption in neutralization could be avoided when used in the purification of food, drug, and biological products [1]. H…  相似文献   
993.
用ICPAES法研究了绿茶和红茶对水溶液中镉(Ⅱ)、铅(Ⅱ)的捕集行为,考察了时间、pH、温度等因素的影响。结果表明,绿茶对水中镉(Ⅱ)、铅(Ⅱ)的捕集30min基本达到平衡,而红茶的捕集平衡时间约为60min。当pH<4时捕集率随pH值减小而显著降低,当pH>4时捕集率变化趋缓;当pH<6时茶样对铅(Ⅱ)的捕集率大于镉(Ⅱ),而当pH>6之后则正相反,这与不同酸度的溶液中茶叶的带电状态及镉(Ⅱ)、铅(Ⅱ)的形态分布有关。升高温度有利于绿茶对镉(Ⅱ)、铅(Ⅱ)的捕集,而红茶变化不大;捕集后的镉(Ⅱ)、铅(Ⅱ)在25℃下用水洗脱困难,其中绿茶与铅(Ⅱ)的相互作用较强。  相似文献   
994.
借助自旋极化隧道模型,对具有不同居里温度的Mn基钙铁矿氧化物的电阻率随温度和磁场的变化行为进行了计算。结果表明,模型给出的结果和献上普遍报道的实验结果在行为上有非常好的一致性,表明这类材料中所观察到的电子输运和磁性质可以基于这一模型而得以理解。  相似文献   
995.
ICP-AES法测定酸枣仁汤中多种金属元素   总被引:11,自引:0,他引:11  
为了探讨中药方剂酸枣仁汤中多种金属元素的测定方法,采用湿法HNO3-H2O2对试样进行消解,用电感耦合等离子体原子发射光谱(ICP-AES)法同时测定酸枣仁汤的中药方剂(酸枣仁、茯苓、甘草、知母、川芎)中钙、铬、铝、铁、钾、镁、锰、锌等元素的含量,各元素回收率在95.5%~106.8%之间,变异系数为1.7%~3.9%。应用本方法测定实际样品,结果令人满意。  相似文献   
996.
The atomic and electronic structures of amorphous CuxZr100-x(x=36,46,50,56,64) alloys were simulated using first-principle calculations within a 400-atom supercell.The pair correlation function,coordination numbers,local cluster structures and electronic density of states were analyzed.Reasonable agreements between the theory and the experiments were obtained.The amorphous alloys exhibit different local cluster structures and can all be explained with cluster formulas [cluster](glue)1,3,where the clusters a...  相似文献   
997.
A two-coordinate copper(Ⅰ)complex,Cu_2(bipy)(H_2L)_2(1)(H_3L=cyanuric acid,bipy=4,4'-bipyridyl),whichexhibits strong photoluminescence,has been synthesized under hydrothermal conditions and structurally character-ized by single crystal X-ray diffraction.The compound crystallizes in the monoclinic space group P2_1/n,with cellparameters:M_r=539.42,a=13.4806(5),b=4.5234(2),c=15.4952(8),β=105.526(3)°,V=910.39(7)~3,Z=2 and μ=3.52 mm~(-1).In the structure the two Cu(Ⅰ)ions are bridged by bipy to form a two-coordinate copper(Ⅰ)dimer.The adjacent dimer units are connected by hydrogen bonding interactions,resulting in 1D zigzag chainsalong the c axis.1 emits intense yellow light when excited with UV light.  相似文献   
998.
Ferromagnetic Fe 3 O 4 nanoparticles were synthesized and then self-assembled into microparticles via a solvothermal method,using FeCl 3 ·6H 2 O as the iron source,sodium oleate as the surfactant,and ethylene glycol as the reducing agent and solvent.The obtained Fe 3 O 4 microparticles were characterized by X-ray powder diffraction (XRD),X-ray photoelectron spectroscopy (XPS),Raman spectroscopy and vibrating sample magnetometer (VSM).The size and morphology of the particles were examined using transmission ...  相似文献   
999.
Protein tyrosine phosphatases(PTPs) are crucial regulators of signal transduction. Among them, PTP-MEG2 is an intracellular enzyme of 593 amino acid residues with a putative lipid-binding domain at the N-terminus. In the present study, we cloned the full-length form of the enzyme and expressed it in E. coli cells as a 6xHis-tagged protein. The majority of the expressed enzyme was found in the inclusion body of E. coli cell extracts. Upon extraction with a buffer containing urea, the recombinant enzyme was p...  相似文献   
1000.
A potential dual inhibitor(4) for exogenous absorption and endogenic synthesis of cholesterol was designed based on the conjugation of the β-lactam pharmacophore of ezetimibe and the δ-lactone pharmacophore of statins. The merger of ezetimibe and statin 4 was synthesized from p-hydroxybenzaldehyde through a ten-step route. 1H NMR analysis showed existence of four pairs of enantiomers(5.7:5.7:1:1, molar ratio). And compound 4 was found to lower total glucose(TG) level in rat serum via a high-cholesterol and ...  相似文献   
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