喷雾干燥-高温固相法制备纳米LiFePO4与LiFePO4/C材料及性能研究

采用喷雾干燥-高温固相法制备纳米LiFePO₄与LiFePO₄/C正极材料，用X-射线衍射，扫描电镜等对合成材料进行了表征，并对以LiFePO₄为正极的电池进行了电化学性能测试。结果表明:材料合成最佳煅烧温度为600 ℃;合成过程中由于碳对LiFePO₄晶型的生长有一定的抑制作用，相对于纯LiFePO₄材料，LiFePO₄/C材料粒径更小;并且，在此最佳合成温度下合成的LiF     

接触角法研究医用聚醚聚氨酯材料表面自由能与界面自由能

<正> 表面性质在医用材料与生物体的相互作用中起着至关重要的作用,如血液相容性材料的表面对血细胞具有吸附、变形、凝血、溶血等作用。表面能和界面能是医用材料的重要研究内容之一,材料的表面能及其极性与非极性分量在影响或控制材料与生物体的相互作用之面一直是医用材料的重要课题。Raier曾提出当材料的临界表面张力在20-30erg/cm~2时,血液相容性好,也有人认为,血液与材料的界面自由能趋于零时,才能     

Synthesis and Crystal Structure of 3,3′-(Hexane-1,6-diyl)bis(1-acetyl-5,5-dimethylhydantoin),a New Inducer of Differentiation

1 INTRODUCTION Hexamethylenebis[acetamide] (HMBA) is an effective agent in phaseⅡclinical trial[1] that induces differentiation of certain types of tumors to nonmalignant phenotypes. In an attempt to discover more efficient inducers, a number of derivatives of HMBA have been synthesized and evaluated in vitro[2, 3]. The results proved that increasing the number of functional groups could enhance the anticancer activity. In addition, it was evident that compounds with six methylene i…     

COORDINATION COPOLYMERIZATION OF STYRENE WITH MALEIC ANHYDRIDE BY RARE-EARTH COORDINATION CATALYSTS

The study on coordination copolymerization of styrene (S) with maleic anhydride (MA) by rare-earth coordination catalysts, NdL_3-Al(i-Bu)_3, has been successfully carried out for the first time. Some features, kinetic behavior, and mechanism of the SMA copolymerization by Nd(naph)_3-Al(i-Bu)_3 system are described and discussed. The copolymex of styrenemaleic anhydride prepared by the NdL_3-Al(i-Bu)_3 systems in benzene at 50℃ is an alternating-rich white powder having high number-average molecular weight of 6—8.5×10~5. The overall activation energy for the polymerization was found to be 10.5KJ/mol. The polymerization was not suppressed by addition of hydroquinone. The catalytic activity of various ligands in NdL_3 for the copolymerization decreases in the following order: Nd (naph)_3>Nd-(P_(507))_3～NdCl_3-6H_2O>Nd(P_(204))_3>Nd(acac)_3. 3H_2O. The experimental results are explained based on a mechanism to be the coordination-type copolymerization in terms of the participation of a monomer-monomer c     

几种常见水果的微量元素分析

运用原子吸收分光光度法测定了几种常见水果中部分微量元素含量。其中榴莲的Mg、Zn、Cu、K含量位于四种水果之首。美国提子中Ca含量最高，芒果中Fe含量最高。以上差别具有统计学意义。六种元素的回收率为90％-106．5％。连续6次测定样品，变异系数(CV)为0．96％。     

A vacuum ultraviolet photoionization mass spectrometric study of acetone

The photoionization and dissociative photoionization of acetone have been studied at the photon energy range of 8-20 eV. Photoionization efficiency spectra for ions CH3COCH3+, CH3+, C2H3+, C3H3+, C3H5+, CH(2-)CO+, CH3CO+, C3H4O+, and CH3COCH2+ have been measured. In addition, the energetics of the dissociative photoionization has been examined by ab initio Gaussian-3 (G3) calculations. The computational results are useful in establishing the dissociation channels near the ionization thresholds. With the help of G3 results, the dissociation channels for the formation of the fragment ions CH3CO+, CH2CO+, CH3+, C3H3+, and CH3COCH2+ have been established. The G3 results are in fair to excellent agreement with the experimental data.     

ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1)

INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do…     

High-efficiency, environment-friendly electroluminescent polymers with stable high work function metal as a cathode: green- and yellow-emitting conjugated polyfluorene polyelectrolytes and their neutral precursors

A series of aminoalkyl-substituted polyfluorene copolymers with benzothiadiazole (BTDZ) of different content were synthesized by Suzuki coupling reaction, and their quaternized ammonium polyelectrolyte derivatives were obtained through a postpolymerization treatment on the terminal amino groups. Copolymers are soluble in environmentally friendlier solvents, such as alcohols. It was found that the efficient energy transfer occurs by exciton trapping on the narrow band gap BTDZ site under UV illumination. Only 1% of BTDZ content is needed to completely quench a fluorene emission for both the neutral and the quaternized copolymers in the neat film. Absolute PL efficiencies of copolymer films were greatly enhanced as a result of the suppression of excimer formation. Light-emitting devices fabricated from these copolymers show high external quantum efficiencies over 3% and 1% for the neutral precursor and the quaternized copolymers, respectively, with high work function metals such as Al as a cathode. To the best of our knowledge, this is the first report on an electroluminescent polymer which bears the high EL efficiency, the electron-injection ability from high work function metals, and the solubility in environment-friendly solvents at the same time. These features make them a promising candidate for the next generation of light-emitting copolymers in PLED flat panel display application.     

离子液体中用Heck反应合成2-取代萘烯丙醇化合物

利用Heck反应, 在离子液体、金属钯或镍、碱和膦配体反应体系中, 由卤代萘与烯丙醇反应, 制得了高收率和高选择性的2-取代萘烯丙醇化合物. 该方法原料便宜易得、操作简单、反应体系可循环使用. 并讨论了醋酸镍替代醋酸钯、不同膦配体、溶剂及碱对反应转化率的影响. 通过核磁共振、红外光谱、质谱和元素分析对产物的结构进行了表征.     

[Ni(dien)_2]_2[Mn(NCS)_6]·H_2O的合成、晶体结构

硫氰酸根的结构为N≡C－S－，其两端的N原子和S原子分别有一对和三对孤对电子，因此，硫氰酸根可采用多种不同的配位模式与金属离子发生配位。硫氰酸根可作为单齿配体与一个金属离子配位，形成M－SCN或M－NCS的单核配合物，也可以作为桥联配体同时与两个、三个甚至四个金属离子配位形成多核配合物犤１～３犦；另一方面，硫氰酸根是一个具有一定共轭性的偶极子，可传递磁相作用。因此，选择硫氰酸根作为桥联配体，将多个顺磁金属离子桥联形成一维、二维或三维结构的多核金属配合物分子，并研究它们的磁性已成为分子磁学的一个研究领域…