地锦草总黄酮最佳提取分离工艺的研究

采用四因素三水平的正交实验方法,对地锦草总黄酮的最佳提取工艺进行了探索.采用乙酸乙酯萃取、酸碱沉淀、铅盐沉淀3种方法,对其最佳分离工艺进行了探索.正交实验结果表明:温浸法中四因素对地锦草黄酮的影响顺序为乙醇浓度>样液比>提取温度>提取时间.通过实验得到了地锦草总黄酮的最佳提取工艺:以10倍体积的50%的乙醇水溶液在80℃浸提1 h.地锦草总黄酮的最佳分离方法为酸碱沉淀法.这些数据为中药地锦草的开发和应用提供了科学依据.     

氢部分选择性催化还原NO反应研究

在低钯含量活性非均布Pd/Al2O3催化剂上，实现了富氧条件下，氢部分选择性催化还原NO过程，低温、富氧条件下NO的转化率高达80％－100％。NO直接分解实验表明，600℃，NO分解转化率在无氧时为17．3％，有0．5％氧存在时接近于0。氢非选择性还原NO条件下，100℃以下，NO转化率为100％。根据实验结果及文献，推测了氢部分选择性还原NO过程中可能存在的反应，不同的反应温度下，NO脱除反应有所不同。在115℃以下，NO还原产物为NH3；115℃－155℃，NO还原产物为NH3、N2O和N2；155℃以上，NO还原产物中无NH3存在。NO还原反应与氢氧反应是平行的竞争反应。     

四氢呋喃与环氧氯丙烷共聚合的研究

<正> 晃玉等曾以BF_3-二元醇(DO)引发四氢呋喃(THF)与环氧氯丙烷(ECH)共聚合,用所得共聚醚制成嵌段聚醚聚氨酯,与用THF均聚醚或THF-环氧丙烷(PO)共聚醚为软段的聚氨酯相比,分别在低温性能及强度上有明显改进.且由于引入氯甲基侧基可作进一步接枝共聚改性。但用BF_3-DO为引发剂很难制得不含环聚体的共聚醚,     

NaCl-CsCl熔盐中Ce(Ⅲ)离子的阴极过程研究

以钨微盘为研究电极采用循环伏安法和方波伏安法研究了温度为873K的NaCl-CsCl熔盐中Ce3 离子的阴极行为.结果表明,摩尔比为1:2的NaCl-CsCl熔盐体系中Ce3 离子分两步还原,其电化学反应历程为:Ce3 e=Ce2 ,Ce2 2e-=Ce.进一步计算得到熔盐体系中Ce3 离子的扩散系数(D).     

硅氧聚合度对细胞毒性的影响

本文采用家兔肺泡巨噬细胞(AM)存活率和细胞过氧化脂质(LPO)值为测定指标,研究了硅氧的聚合度对其细胞毒性的影响。结果表明:各种聚合度的硅氧都有一定的细胞毒性,聚合度愈大,细胞毒性也愈大。胶体SiO_2的粒径增大,其细胞毒性降低。十硅酸盐及粒径小于5nm的硅溶胶的细胞毒性大于α-石英。聚合度小于6的低聚硅酸及其盐、粒径18nm以上的硅溶胶以及硅胶H的毒性皆小于α-石英。本实验细胞存活率降低和过氧化脂质值升高的趋势基本一致,这表明硅氧可能主要与细胞表面膜作用,膜上磷脂等表面活性物质被氧化和变性,从而导致细胞损伤。     

超支化双亲水性嵌段共聚物对CaCO3结晶影响的研究

采用合成的聚乙二醇-超支化聚酯(PEG-hb-DMPA)的线性-超支化杂化二嵌段共聚物, 探讨了羧端基树状功能化的杂化嵌段共聚物对CaCO₃结晶的影响，并用FTIR、XRD、SEM等对产物进行了表征。结果表明，羧端基的双亲水性嵌段共聚物对CaCO₃结晶形貌乃至晶型均具有显著调控作用，比较高的浓度(1.67 g·L^-1, >10 min)或较低浓度作用较长时间(0.33 g·L^-1, 24 h)均得到了呈较均匀球粒形态的球霰石CaCO₃结晶。     

Dependence of Performance of Organic Light-emitting Devices on Sheet Resistance of Indium-tin-oxide Anodes

IntroductionIndium-tin-oxide(ITO) has been widely used asthe anode material in organic light-emitting devices(OLEDs) because of its high transmittance in the visi-ble region and low electrical resistivity. In the pastyears, many investigations focused on …     

Novel expanded porphyrinoids with multiple-inner-ring-fusion and/or tunable aromaticity

Novel expanded porphyrinoids with advanced structure features have a wide range of benefits (such as multi-metal coordination and facile tunable aromaticity) not offered by their normal porphyrin analogues. Considering research efforts have been devoted to address their limited synthetic accessibility issue. This review highlights some of these recent synthetic progresses towards these novel expanded porphyrinoids.     

Growth of porous single-crystal Cr2O3 in a 3-D mesopore system

Single-crystal Cr2O3 with regular mesopores has been synthesized using mesoporous silica KIT-6 as a template and characterized by using XRD, HRTEM and nitrogen adsorption/desorption.     

Acetic acid induced self-assembly of supramolecular compounds [Et4N]3[(WS4Cu2)2(mu-CN)3].2MeCN and [PPh4][WS4Cu3(mu-CN)2].MeCN from preformed clusters [A]2[WS4(CuCN)2] (A = Et4N, PPh4)

Reactions of two preformed trinuclear W/Cu/S clusters, [A](2)[WS(4)(CuCN)(2)] (1: A = Et(4)N; 2: A = PPh(4)), with different concentrations of acetic acid in MeCN generate two interesting 2D polymeric clusters [Et(4)N](3)[(WS(4)Cu(2))(2)(mu-CN)(3)].2MeCN (3), and [PPh(4)][WS(4)Cu(3)(mu-CN)(2)].MeCN (4), respectively. Compound 4 can also be readily obtained in a high yield from the reaction of 2 with equimolar [Cu(MeCN)(4)]PF(6) in MeCN. These compounds have been characterized by elemental analysis, IR spectra, thermal analysis, and single-crystal X-ray diffraction. An X-ray analysis reveals that compound 3 retains the WS(4)Cu(2) cluster core, which serves as a 3-connecting node to link equivalent nodes via single cyanide bridges, forming an anionic 2D (6,3) net. Compound 4 consists of a T-shaped WS(4)Cu(3) core, which also acts as a 3-connecting node, with links to 3 equivalent clusters either through single or double cyanide bridges, affording a different anionic 2D (6,3) network. The acetic acid induced aggregation of 3 and 4 from the two cluster precursors 1 and 2 suggests that this simple synthetic strategy is likely to be applicable to many related systems.