CdS/TiO2复合纳米微粒的原位合成及性质研究

采用一种新方法,在TiO₂表面原位合成CdS纳米微粒,并用红外光谱跟踪了CdS/TiO₂复合纳米微粒的形成过程.紫外吸收光谱研究表明TiO₂对CdS纳米微粒的形成有很好的稳定作用,荧光光谱研究结果表明,这种纳米异质结构有着良好的电荷分离.     

Study on laminar viscosity and zero shear viscosity of latex systems

The flowing nature and rheological properties of polymethyl methacrylate latex systems in a coaxial cylinder viscometer were studied on the basis of laminar shear flow model and rheological experimental data. The physical meaning of laminar viscosity (eta(i,j)) and zero shear viscosity (eta(0)) were described. We assumed that laminar shear flows depended on position and shear time, so microrheological parameters were the function of position and shear time. eta(i,j) was the viscosity of any shear sheet i between two neighboring laminar shear flows at time t; j was denoted as j=t/Deltat; and Deltat was the interacting time of two particles or two laminar shear flows. tau(i,j) and gamma(i,j) were shear stress and shear rate of any shear sheet i at j moment. According to Newton regulation tau(i,j)=eta(i,j)gamma(i,j), apparent viscosity eta(a) should be a statistically mean value of j shear sheets laminar viscosity at j moment, i.e., eta(a)= summation operator(i=j)eta(i,j)gamma(i,j)/ summation operator(i=j)gamma(i,j). eta(0) was defined as shear viscosity between a laminar shear flow and a still fluid surface, i.e., eta(0)=(tau(i,j)/gamma(i,j))(j-i-->0). These new ideas described above may be helpful in the study of the micromechanisms of latex particle systems and worthy of more research.     

Arylcarbamoylated allylcarbamido-β-cyclodextrin: synthesis and immobilization on nonfunctionalized silica gel as a chiral stationary phase

Four new chiral stationary phases based on mono-(6^A-allylcarbamido-6^A-deoxy)-arylcarbamoylated β-cyclodextrin were synthesized. The chiral stationary phase of phenylcarbamoylated β-cyclodextrin exhibited excellent separation capability for a variety of chiral compounds. Compared with the previous work, it was found that the spacer remained on the surface of the silica gel and decreased the enantioseparation capability.     

Synthesis of optically active ring-A substituted tryptophans as IDO inhibitors

The first synthesis of optically active 7-methoxy-d-tryptophan as well as other ring-A substituted tryptophans is described.     

Intracellular Entropy‐Driven Multi‐Bit DNA Computing for Tumor Progression Discrimination

Tumor progressions such as metastasis are complicated events that involve abnormal expression of different miRNAs and enzymes. Monitoring these biomolecules in live cells with computational DNA nanotechnology may enable discrimination of tumor progression via digital outputs. Herein, we report intracellular entropy‐driven multivalent DNA circuits to implement multi‐bit computing for simultaneous analysis of intracellular telomerase and microRNAs including miR‐21 and miR‐31. These three biomolecules can trigger respective DNA strand displacement recycling reactions for signal amplification. They are visualized by fluorescence imaging, and their signal outputs are encoded as multi‐bit binary codes for different cell types. The results can discriminate non‐tumorigenic, malignant and metastatic breast cells as well as respective tumors. This DNA computing circuit is further performed in a microfluidic chip to differentiate rare co‐cultured cells, which holds a potential for the analysis of clinical samples.     

Nickel(0)‐Catalyzed Enantioselective [3+2] Annulation of Cyclopropenones and α,β‐Unsaturated Ketones/Imines

Ni⁰‐catalyzed chemo‐ and enantioselective [3+2] cycloaddition of cyclopropenones and α,β‐unsaturated ketones/imines is described. This reaction integrates C?C bond cleavage of cyclopropenones and enantioselective functionalization by carbonyl/imine group, offering a mild approach to γ‐alkenyl butenolides and lactams in excellent enantioselectivity (88–98 % ee) through intermolecular C?C activation.     

A pure blue light emitting binaphthyl derivative：Synthesis and properties

A binaphthyl derivative with pyrene on 3 and 3＇ positions was synthesized and characterized via Suzuki coupling reaction. Emission maximum in solution was located at 390 nm with a quantum efficiency of 68% by taking 9,10-diphenyl anthracene as reference,while it is shifted to 450 nm with FWHM of 104 nm resulting from aggregation state in solid film.Glass transition temperature（Tg）and decomposition temperature were measured to be 184 and 447℃,respectively,by DSC and TGA.Unlike its photoluminescence spectrum,electroluminescent spectrum peaked at about 460 nm and shows a FWHM of 69 nm corresponding to a pure blue emission.The turn-on voltage,luminance and efficiency maximum were 5 V,2953 cd/m^2 and 1.37cd/A with CIE color coordinate of（0.16,0.15）,in the device structure of ITO/NPB（40nm）/PY-BN-PY（15nm）/BPhen（40nm）/Mg：Ag.     

1-(2-萘基)-3-甲基-5-吡唑啉酮衍生试剂的制备及其在高效液相色谱-质谱法测定糖类化合物中的应用

以1-(2-萘基)-3-甲基-5-吡唑啉酮(NMP)作为柱前衍生试剂,建立了简单、灵敏的糖类组分的反相高效液相色谱测定方法。NMP与糖在氨为催化剂的条件下,于70 ℃下反应可获得稳定的衍生产物。在Hypersil ODS 2反相色谱柱上,实现了8种单糖的基线分离。衍生物线性相关系数均大于0.9985,检出限为0.58～1.1 pmol。利用柱后在线串联质谱的电喷雾电离正离子模式监测,获得了各组分的质谱定性及裂解规律,特别是m/z 473的特征碎片离子可作为单糖NMP衍生物的判定依据。与1-苯基-3-甲基-5-吡唑啉酮(PMP)相比,NMP对糖的衍生化具有灵敏、简单、质谱裂解规律性强、重现性好等优点。该方法用于测定油菜花粉多糖中的单糖组成,结果令人满意。     

有机染料敏化纳米晶太阳能电池

本文综述了有机染料敏化纳米晶太阳能电池的研究现状,简要介绍了有机染料敏化纳米晶太阳能电池的结构和工作原理以及氧化物电极、对电极和电解质的设计思路和制备情况。重点介绍了有机染料的研究现状,包括香豆素类染料、多烯类染料、噻吩类染料、天然染料、半花菁类染料、卟啉类染料、三苯胺类染料、苝类染料等。同时讨论了若干影响有机染料敏化太阳能电池性能的因素,提出了提高光电转换效率的设想与对策,对未来的发展进行了展望。     

大米中硒含量的测定

为使人们更好地控制和调节硒的摄入量,用紫外分光光度法测定了大米中的硒含量。样品通过混酸消化,将有机硒转化成无机硒,酸性条件下,Se(Ⅳ)与邻苯二胺反应,产物在335nm有最大吸收峰。测定结果表明,天津小站米、东北米、丝苗米、泰国香米、富硒米的有机硒含量分别为:0.041、0.046、0.035、0.034、2.021μg/g,有机硒含量占总硒含量的比例分别是89.13%、82.14%、87.50%、80.95%、98.92%。富硒米硒含量及有机硒的比例明显高于其它种类的米。