Synthesis, crystal structure and magnetic properties of a novel manganese(II)-nitronyl nitroxide-azido(μ_(1,1) and μ_(1,3)) one-dimensional complex

A novel one-dimensional manganese(Ⅱ) complex containing nitronyl nitroxide radical [Mn2(IM2-py)2(Ac)2((μ1.1-N3)(μ1,3-N3) . EtOH]n was synthesized and characterized structurally and magnetically. It crystallizes in the monoclinic space group p21/n. Each Mn(Ⅱ) ion is six-coordinated in a distorted octahedral environment. The two N atoms of the nitronyl nitroxide radical and the two O atoms of acetate ligands are in the equatorial plane, whereas the two different azido bridging ligands are in trans axial position. Mn(Ⅱ) ions are linked by nitrogen atom of μ1,1-azido and oxygen atoms of two carboxy groups to form a Mn-Mn unit. Mn-Mn units are linked by azido ligands through u1,3 bridging style to form a one-dimensional chain. The compound is connected by the coordination bonds,π-π interactions and hydrogen bonds as a three-dimensional structure. Magnetic susceptibility data support that there are stronger antiferromagnetic interactions between the radical and Mn(Ⅱ) ion, weak antiferromagnetic inter     

The Aggregation Kinetics of Colloidal Particles of Basic Yttrium Carbonate

Studyofthegrowthprocessofcolloidalparticlesofnonequilibriumandirreversibilityisanactiveareaofresearch.Therecognitionofcolloidalaggregatesasfractalobjectshasinspiredalargenumberofexperimentalandtheoreticalstudiesonthestructuralandkineticaspectsofaggregationprocesses"'.Morerecently,kineticsofhematiteaggregationbypolyacrylicacidhavebeenstudiedbyzhangandBume3.Theprimaryhematiteparticleswerequiteuniformandfairlyspherical.Inthispaper,wewillreportthesizeevolutionoffractalaggregatesofinitiallypolydis…     

载体和担载酸对乙烯直接氧化合成乙酸反应的影响

 在固定床流动反应器上研究了Pd－酸／载体体系催化乙烯直接氧\r\n化合成乙酸的反应，并对载体相同但担载酸强度不同的催化剂的催化活\r\n性进行了比较．结果表明，担载酸的强度明显影响催化剂的活性，酸强\r\n度越大其催化活性越高．用NH3－TPD和异丙醇脱水探针反应表征了二氧\r\n化硅、活性碳和酸性白土三种载体担载的Pd－H4SiW12催化剂的酸性，\r\n并测试了三种催化剂的催化活性．结果表明，载体通过影响担载酸的强\r\n度而影响催化剂的活性，载体上的强酸中心越多，催化剂的活性越高．\r\n测定了二氧化硅、活性碳和酸性白土三种载体担载的Pd－H4SiW12催化\r\n剂上Pd的分散度，并与其催化活性相关联．结果表明，决定乙烯直接氧\r\n化生成乙酸反应活性的主要因素是催化剂的酸强度而不是Pd的分散度．     

(Y,Gd)VO_4∶Eu~(3+)的紫外-真空紫外发光特性

用高温固相法合成了Y1-xGdxVO4∶Eu3 (0≤x≤1)系列单相样品并研究了其发光特性。在254nm激发下,观察到最大强度位于619nm的红色发射峰且其强度在Y/Gd=0.4/0.6时达到最大。在147nm激发下的发射峰与紫外下的一致,发射强度也是在Y/Gd=0.4/0.6时达到最大,大约是商用(Y,Gd)BO3∶Eu3 荧光体的65%。619nm监控下的真空紫外激发光谱由峰值位于158nm,204nm,247nm以及300nm的系列激发带组成,归属于钒酸根的基质吸收以及Gd3 、Y3 和Eu3 的电荷迁移带吸收。相对(Y,Gd)BO3∶Eu3 中Eu3 占据中心对称格位,(Y,Gd)VO4∶Eu3 中Eu3 占据非中心对称格位,其真空紫外下光谱色纯度更好。色坐标分别为(0.632,0.355),(0.672,0.328)。     

表面活性剂模板在空气-水界面ZrO2薄膜中的稳定性

采用模板——十二烷基苯磺酸(DBS-H)在空气-水界面组装ZrO₂薄膜，研究了DBS-H在ZrO₂自组装薄膜中的水溶性、化学稳定性、热稳定性和光化学稳定性。模板的各类稳定性将直接控制ZrO₂薄膜结构，主要表现在层间距变化上。从模板与Na₂SiO₃反应的研究中获得了一种制备ZrO₂ / SiO₂复合氧化物薄膜的新方法，并推测出该复合薄膜的结构。     

DNA电化学生物传感器测定水中痕量铅

采用物理涂附法将单链DNA固定到金表面得到ssDNA/Au修饰电极。研究表明,该电极在pH 5,0.2 mol/L NaAc-HAc缓冲底液中,可用于测定水中痕量Pb2 。Pb2 以Pb-DNA络合物的形式吸附在电极上,以示差脉冲伏安法测定Pb2 ,在0.15 V(vsSCE)处有灵敏的氧化峰,其峰电流与Pb2 浓度在5.0×10-8~1.0×10-6mol/L范围内呈良好的线性关系,此法的检测限为2.0×10-8mol/L,该修饰电极的稳定性和抗干扰性都较好。用该电极对饮用水中的Pb进行检测,得到了满意的结果。     

Retention behaviour of carboxylic acid methyl esters in supercritical fluid chromatography

The study on retention behavior in supercritical fluid chromatography (SFC) is necessary to understand the mechanism of the various interactions in SFC. The retention of SFC in carboxylic acid methyl ester/polymethylsiloxane/CO2 system was studied systematically and the retention behavior of this kind of compounds under various typical operation conditions was described using the method of an alternative unified theory of chromatographic retention. The results illustrated that expression: Ink.= a + b/T + cp + dp/T + ep2/T can be used to describe quantitatively the retention behavior of carboxylic acid methyl ester/polymethylsiloxane/CO2 system in the ranges of reduced density from 0.549 to 1.411. It was also found that the entropy of solute in stationary phase is dependent on the density of supercritical fluid (SF) under typical operating conditions of SFC.     

新型杂多配合物K3H2[GeW8Mo3VO40]·4H2O的合成与晶体结构

用分步酸化、分步加料法合成出新型杂多配合物K3H2[GeW8Mo3VO40]·4H2O,并用X射线单晶衍射法测定其晶体结构,该晶体属单斜晶系,C2空间群,a＝1.894 4(4)nm,b＝3.292 0(7)nm,c＝1.249 4(2)nm,β＝90.25(3)°,V＝7.792(4)nm3,Z＝6.最终偏差因子R＝0.063.RW＝0.067.     

MORPHOLOGICAL STUDIES ON THERMOTROPIC LIQUID CRYSTALLINE POLYESTER——MORPHOLOGY OF SHEAR ORIENTED FILMS

The morphology of shear-oriented films of a thermotropic liquid crystalline polyester containing a triad ester mesogenic unit and a flexible spacer has been investigated in details. The formation conditions and process, the fine structures and the relaxation process of mat structure in the oriented films have been observed and discussed.     

电爆炸箔断路开关的理论和实验研究

 采用金属箔电爆炸过程的二维数值计算模型，对含电爆炸金属箔断路开关的电感储能脉冲功率调节系统进行了数值计算。以此为基础，研制出了一种低电感型的电爆炸箔断路开关，并以4μF/75kV脉冲电容器组作为初级能源，13Ω电阻作为负载进行实验研究。研究结果表明：在负载上可获得约250kV，脉宽大于400ns的脉冲电压。