Strain Effect on Photoluminescences from InGaN MQWs with Different Barriers Grown by MOCVD

InGaN/GaN MQWs, InGaN/AlGaN MQWs and InGaN/AlInGaN MQWs are grown on （0001） sapphire substrates by MOCVD. Membrane samples are fabricated by laser lift-off technology. The photoluminescence spec-ra of membranes show a blue shift of peak positions in InGaN/GaN MQWs, a red shift of peak positions in InGaN/AlGaN MQWs and no shift of peak positions in InGaN/AIlnGaN MQWs from those of samples with substrates. Different changes in Raman scattering spectra and HR-XRD （0002） profile of InGaN/AlInGaN MQWs, from those of InGaN/GaN MQWs and InGaN/AlGaN MQWs, are observed. The fact that the strain changes differently among InGaN MQWs with different barriers is confirmed. The AIlnGaN barrier could adjust the residual stress for the least strain-induced electric field in InGaN/AIlnGaN quantum wells.     

低温高背压氘团簇源特性研究

为了产生大尺度氘团簇用于与强激光相互作用研究，研制了低温高背压团簇源.利用瑞利散射法对团簇尺度与气体背压相关性和团簇的形成演变过程进行了研究.得到团簇尺度N_c随背压的指数变化关系为N_c∝P^2.89₀，当气体温度为80K，背压P₀为48×10⁵Pa时，氘团簇尺度N_c≈2630，并得到了团 关键词： 氘团簇 团簇源 瑞利散射 激光与团簇相互作用     

一维链状三苯基锡肉桂酸酯配合物的合成、结构及量子化学研究

三苯基氯化锡与肉桂酸按物质的量比1∶1在苯和乙醇混合溶剂中反应合成了一维链状三苯基锡肉桂酸酯。经X-射线衍射方法测定了其晶体结构,配合物属单斜晶系,空间群为P21/c,晶体学参数a=1.281 28(9)nm,b=1.145 90(8)nm,c=1.829 01(4)nm,β=120.784(4)°,V=2.307 0(3)nm3,Z=4,Dc=1.431 g.cm-3,μ(Mo Kα)=11.27 cm-1,F(000)=1 000,R1=0.025 2,wR2=0.058 0。配合物通过肉桂酸羧基桥联,形成五配位的三角双锥构型的链状结构。对其结构进行量子化学从头计算,探讨了配合物的稳定性、分子轨道能量以及一些前沿分子轨道的组成特征。     

有机太阳能电池研究进展

为了减轻当前能源危机所带来的压力,各国在太阳能电池等清洁能源领域投入了大量的人力、物力和财力.由于有机太阳能电池具有独特的优点(有机材料易于修饰,器件制备方法简便且可制备出柔韧器件),并且随着相关研究的深入,有机太阳能电池的能量转换效率逐步得到提高,这昭示了有机太阳能电池商业化的美好前景,目前已经有大批科研工作者投身于有机太阳能电池领域的研发工作.文章从太阳能电池小分子材料、聚合物材料和提高有机太阳能电池能量转换效率的方法这三方面入手,对有机太阳能电池领域进行综述.     

MgCl2在LiCl-KCl熔盐中的电化学特性

研究了温度范围在723-908 K的LiCl-KCl 熔盐体系中MgCl₂的电化学行为和热力学性质. 循环伏安和方波伏安法研究表明镁离子的电化学还原过程为包含了两个电子转移的一步反应. 利用Berzins 和Delahay 方程计算了不同温度下的镁离子的扩散系数, 并通过Arrhenius 公式计算了镁离子在LiCl-KCl 熔盐体系中的扩散活化能. 采用开路计时电位法得到了不同温度下的Mg(II)/Mg(0)体系的平衡电位, 并结合电动势法计算了在LiCl-KCl 熔盐体系中Mg(II)/Mg(0)体系的标准形式电位. 根据不同温度下的标准形式电位, 计算得到了MgCl₂在LiCl-KCl 熔盐体系中的熵变和焓变以及不同温度下的活度系数.     

Extraction of ytterbium via co-reduction of Al(III) and Yb(III) from LiCl–KCl melt on W electrode

Anhydrous ytterbium chloride was obtained via solid-phase reaction from Yb₂O₃ with AlCl₃ as a chlorination agent. The electrochemical behavior of the chloridized Yb₂O₃ was investigated on W electrodes in LiCl–KCl and LiCl–KCl–AlCl₃ melts by cyclic voltammetry and square wave voltammetry. The results showed that the reduction/reoxidation of Yb(III)/Yb(II) was reversible and controlled by diffusion. The signals related to the formation of two Al–Yb intermetallic compounds were detected in LiCl–KCl–AlCl₃ melt. Potentiostatic electrolysis was carried out in LiCl–KCl–AlCl₃–YbCl₃ melt on W electrodes at 943 K at different potentials and Al₃Yb, Al₂Yb, AlLi and Al₂Li₃ phases were detected in deposits. Then, the extraction of ytterbium was performed. The currents evolution was recorded by square wave voltammetry and the extraction efficiency was evaluated via inductive coupled plasma atomic emission spectrometer analysis during electrolysis. The initial extraction rate is much higher than that at longer times. The extraction efficiency was about 98.0 % for Yb(III) after potentiostatic electrolysis for 60 h at ?1.84 V in LiCl–KCl–AlCl₃–YbCl₃ melt.     

Synthesis,Crystal Structure,and Thermal Stability of a Dibutyltin Complex {[4-Et2NC6H3（O）C=NC6H3（O）- 5-NO2]（n-Bu2Sn）}2 and Its Interaction with DNA

The Schiff base organotin(IV) complex {[4-Et2NC6H3(O)C=NC6H3(O)-5-NO2](nBu2Sn)}2 has been synthesized via the reaction between 4-(diethylamino) salicylaldehyde-2-amino-4-nitrophenol Schiff base(H2L) and dibutyltin oxide. Complex C1 has been characterized by IR, 1H NMR, 13 C NMR spectra, and elemental analysis, and its crystal structure was determined by X-ray diffraction. It crystallizes in the monoclinic system, space group P21/n with a = 15.6559(8), b = 9.1657(5), c = 18.8351(10) , β = 107.3440(10)°, Z = 4, V = 2579.9(2) 3, Dc = 1.442 Mg·m-3, μ(MoKα) = 1.025 mm-1, F(000) = 1152, R = 0.0250 and wR = 0.0633. The central Sn atom is coordinated in a hexadentate manner to assume a distorted octahedral configuration. Complex C1 was studied by TGA analysis in air atmosphere. The interaction between complex C1 and the herring sperm DNA was realized through the intercalation of the complex based on the studies by EB fluorescent probe.     

Enhanced dispersibility and thermal stability of β-cyclodextrin functionalized graphene

A series of β-cyclodextrin （CDs） functionalized graphene nanohybrids have been successfully fabricated utilizing the classical covalent modification methods at different reaction temperatures. It is very interesting that although both CDs and graphene oxide （GO） could he easily decomposed, the effective combination of GO with CDs leads to significantly enhanced thermal stability of graphene derivatives （GO-CDs）. Moreover, the introduction of CDs could dramatically improve the dispersibility promotion of our products in both polar/protic and nonpolar/aprotic solvents, which will contribute to the preparation of polymer nanocomposites and increase of their thermal stability. The improved thermal degradation temperatures can be obtained for polyvinyl alcohol after filling with as little as 1 wt.% of the hybrid. The obtained products could be potentially used in heat-retardant or thermal-control materials.     

酶联免疫法测定人碱性成纤维细胞生长因子脂质体的包封率

建立了一种灵敏的定量检测人碱性成纤维细胞生长因子(hbFGF)脂质体中hbFGF含量的酶联免疫(ELISA)方法,应用于测定hbFGF脂质体的包封率。通过用hbFGF标准品溶液包被酶标板,加入特异性的鼠抗人hbFGF抗体(一抗)和山羊抗鼠IgG(二抗),采用多因素棋盘滴定方法确定最佳实验条件为:一抗浓度200μg/L,二抗浓度50μg/L。本方法的检出限为0.86μg/L,工作浓度范围1.0~10μg/L,批内RSD为3.95%~4.27%,批间RSD为4.19%~7.21%,不同操作者批内和批间的RSD分别为6.21%和9.12%,可重复性良好。本方法测定hbFGF脂质体超滤液和氯仿提取液中hbFGF含量分别为(3.325±0.193)μg/L和(18.454±1.063)μg/L,组内RSD分别为4.69%和4.52%。hbFGF脂质体包封率为82.06%。本方法特异性高、重复性好、快速、简便,可用于hbFGF脂质体包封率及其它含hbFGF制剂的含量测定。     

Air-stable and phosphine-free iridium catalysts for highly enantioselective hydrogenation of quinoline derivatives

Enantioselective hydrogenation of quinoline derivatives catalyzed by phosphine-free chiral cationic Cp*Ir(OTf)(CF 3TsDPEN) complex (CF 3TsDPEN = N-(p-trifluoromethylbenzenesulfonyl)-1,2-diphenylethylene-diamine) afforded the 1,2,3,4-tetrahydroquinoline derivatives in up to 99% ee. The reaction could be carried out with a substrate-to-catalyst molar ratio as high as 1000 in undegassed methanol and with no need for inert gas protection.