正五边形的一种简易近似作图法及其改进

辽宁南部一带,流传一种正五边形的简易作图法,这是我们在几次下乡调查中,向木工师傅学到的.作法是:     

无限弹性介质中多层园柱结构受脉冲波作用的响应计算

本文给出了一种分析计算无限弹性介质中多层园柱结构对脉冲波的响应的方法。在多层结构的响应分析中,方程的个数随结构的层数而增加,使计算变得更加困难,本文基于多层结构的特点,采用了迁移矩阵,用这种方法不管结构层数的多少,方程总是保持为四组,使计算得到了简化。 文中分析了带覆盖的双层结构和三层结构方案,可供设计参考。     

Ag3PO4溶解热力学函数的晶面效应与温度效应

在室温下制备了立方体{100}、 四面体{111}、 菱形十二面体{110}和块体Ag₃PO₄微晶, 并进行了表征. 测定了其在不同温度下水溶液中的电导率, 结合强电解质溶液和溶解热力学理论, 得到了Ag₃PO₄微晶的溶解热力学函数. 以具有不同晶面的Ag₃PO₄微晶为模型, 研究了纳米材料溶解热力学函数的晶面效应和温度效应. 结果表明, 具有{110}晶面的菱形十二面体Ag₃PO₄的标准摩尔溶解吉布斯自由能()、 标准摩尔溶解焓()和标准摩尔溶解熵()最大, 具有{100}晶面的立方体Ag₃PO₄次之, 具有{111}晶面的四面体Ag₃PO₄最小; 溶解平衡常数(K_{\mathrm{SP}})和随着温度的升高而增大.     

咔唑并噻唑类蓝色荧光材料的合成及电致发光性质

以钯为催化剂,通过C—C和C—N偶联反应分别合成了两种咔唑并噻唑类蓝色荧光材料:TCz-PCz和TCz-TPA,并采用质谱、~1H NMR、~(13)C NMR和元素分析等对其结构进行了鉴定.系统地研究了这些材料的热稳定性、光物理性质和电化学行为,结果表明这些化合物具有良好的热稳定性和形态稳定性,热分解温度高达400℃,玻璃化转变温度为119℃.在溶液中,这两种材料均发射出强的蓝光,荧光量子效率分别为71%和73%;这些分子的HOMO能级分别为-5.41和-5.21 eV,较高的HOMO能级有利于器件中空穴从空穴传输层向发光层的注入和传输.以TCz-PCz为发光材料,通过真空蒸镀技术制备了非掺杂型有机电致发光器件,研究了其电致发光性能.结果显示该器件具有稳定的蓝光发射,启亮电压仅为3.1 V,最大发光亮度和电流效率分别为2190 cd·m~(-2)和2.88 cd·A~(-1).     

甘肃某复杂铌稀土矿石矿物学及选矿工艺特性研究

为探索甘肃某复杂铌稀土矿石的开发利用价值,为资源综合评价提供基础数据和重要依据,利用MLA, SEM, XRF, ICP等先进的检测手段结合显微镜鉴定、单矿物提纯、矿物物理化学性质研究等工艺矿物学研究方法,对该矿石进行矿物学特性和选矿工艺特性研究。研究表明:该矿石属碱性花岗岩型铌稀土锆矿石,有用矿物种类繁多,嵌布粒度微细,嵌布关系复杂;有用矿物与脉石矿物磁性分区和比重差别明显;从原矿中分选稀土矿物、铌矿物和锆石,理论回收率分别为66.97%, 69.95%和82.64%。采用阶段磨矿阶段选别,磁选为主重选为辅,浮选扫尾的选矿分离原则流程,可实现有价金属综合回收和尾矿综合利用。     

Stationary Fluid Dynamic Behaviour of V-Shaped Diffuser/Nozzle Elements for Valveless Micropump

A novel type of V-shaped （isosceles triangle cross-section） diffuser/nozzle element is proposed for use for valveless micropump. Stationary fluid dynamic behaviour of V-shaped diffuser/nozzle elements in a valveless micropump is investigated by experiment and simulation. Both the results agree well with each other when the Reynolds number is higher than 100 and the pressure loss coefficient ratio of micropump nearly always keeps a constant. For a single V-shaped diffuser, the general trends of variation of pressure loss coefficient with opening angle and Reynolds number are opposite in small and large angles. Compared with conical and flat-wall diffusers, V-shaped diffuser shows the smallest pressure loss when the Reynolds number is 200.     

Nitrogen Dioxide Sensing Properties and Mechanism of Copper Phthalocyanine Film

Copper phthalocyanine film, a p-type organic semiconductor, is synthesized by vacuum sublimation and its surface morphology is characterized by SEM. A silicon-based copper phthalocyanine film gas sensor for NO2 detection is fabricated by MEMS technology. The results show that the resistance and sensitivity of copper phthalocyanine film decrease obviously as the NO2 concentration increases from Oppm to lOOppm. However, the sensitivity nearly keeps a constant of O. 158 between 30 ppm and 70 ppm. The best working temperature of the gas sensor is 90℃ for NO2 gas concentrations of lOppm, 20ppm and 30ppm, which is much lower than that of general metal oxide gas sensor.     

Two Copper Complexes Based on Pyrazole-3-carboxylic Acid as Heterogeneous Catalysts for Highly Selective Oxidation of Alkylbenzenes

Two new copper complexes based on pyrazole-3-carboxylic acid(H_2pca)ligand,Cu(Hpca)_2(H_2O)_2·2H_2O(1)and Cu_2(pca)_2(H_2O)_4(2)have been synthesized and fully characterized by single-crystal X-ray diffraction(SXRD),infrared spectroscopy(IR),thermal gravity analysis(TGA),powder X-ray diffraction(PXRD)and elemental analyses.Complex 1 is mononuclear while complex 2 shows a dinuclear structure.Complex 1 crystallizes in the monoclinic system,space group P2_1/c with Z=2,a=6.5591(5),b=21.696(2),c=4.9486(2)?,V=680.94(9)?~3,F(000)=366,D_c=1.745 g/cm~3,μ=1.650 mm~(-1),the final R=0.0340 and w R=0.0792.Complex 2crystallizes in the monoclinic system,space group P2_1/n with Z=2,a=5.1935(4),b=9.6052(7),c=12.7347(9)?,V=634.44(8)?~3,F(000)=420,D_c=2.195 g/cm~3,μ=3.404 mm~(-1),the final R=0.0305 and w R=0.0653.The three-dimensional frameworks of two complexes are formed by the O-H···O and N-H···O hydrogen bonding interactions.Notably,two copper complexes are further used as catalysts in the oxidation of alkylbenzenes using t-butylhydroperoxide(TBHP)as the oxidant and they exhibit excellent catalytic performance(Conv.up to 98.9%,Sele.up to 98.7%).     

采用优化的DFTB参数对铜(111)表面碳二聚化的分子动力学研究（英文）

针对铜表面化学反应,我们发展了一套铜-碳体系的密度泛函紧束缚(DFTB)参数。测试结果表明这套参数可以很好的描述吸附铜或碳原子前后铜表面的几何结构和能量。基于这套参数,我们对Cu(111)表面的碳二聚化过程进行了分子模拟研究。即使在高温下,直接的分子动力学模拟也很难观察到碳二聚体的形成。这是因为高温下铜表面显著的结构弛豫一定程度上阻止了二聚化。为了研究高温下铜表面碳二聚化的机理,我们进行了赝动力学模拟。发现在二聚化的过程中,碳原子形成C-Cu-C桥状结构以后,会绕中间Cu原子转动,最后形成碳二聚体。1300 K下碳二聚化的自由能垒约0.9 eV。