弯曲共振法测量材料的杨氏模量实验改进

针对共振法测量杨氏模量实验中存在精确度和获取共振频率上的不足,在原装置中增加高度调节装置和水平仪,通过实验操作对共振阶数进行判断.实验结果证明选用共振二阶型态测量杨氏模量较有优势.     

Efficient,microwave-mediated synthesis of benzothiazole- and benzimidazole-based heterocycles

Research on Chemical Intermediates - 1-(Benzothiazol-2-yl)-3-(N,N-dimethylamino)-2-(phenylsulfonyl)prop-2-en-1-one (3) and...     

Effect of TiO2 nanorod thickness on optical properties of Ba0.8Sr0.2TiO3 film via hydrothermal method

Journal of Solid State Electrochemistry - Hydrothermally produced perovskite-type barium strontium titanate Ba0.8Sr0.2TiO3 (BST) nanorods deposited on TiO2 substrate for 2 h at...     

超高效液相色谱-串联质谱多目标分析沉积物中的微量有机紫外线吸收剂

利用超声波辅助萃取、通过硅胶柱层析法净化,联合超高效液相色谱-串联质谱技术建立了同时检测沉积物中12种微量有机紫外线吸收剂的定性定量方法.优化了萃取条件,比较了净化过程中硅胶活化温度、洗脱剂种类和体积对回收率的影响.样品在甲醇中经超声波辅助萃取3次,每次15 min;硅胶活化温度为160 ℃,洗脱剂为甲醇/二氯甲烷混合液(1∶1,V/V);质谱采用大气压力化学电离源正离子模式,数据采集为选择反应监测模式.目标物的回收率为55％～118％,方法定量限为1～ 250 pg/g,有效控制了基质干扰.采用本方法初步分析了珠江广州城市河段表层沉积物中的有机紫外线吸收剂,除UV-327外,其它目标物均被检出,含量最高可达12.0 ng/g(干重).     

A Simple Accurate Method for Solving Fractional Variational and Optimal Control Problems

We develop a simple and accurate method to solve fractional variational and fractional optimal control problems with dependence on Caputo and Riemann–Liouville operators. Using known formulas for computing fractional derivatives of polynomials, we rewrite the fractional functional dynamical optimization problem as a classical static optimization problem. The method for classical optimal control problems is called Ritz’s method. Examples show that the proposed approach is more accurate than recent methods available in the literature.     

An inverse problem for a family of two parameters time fractional diffusion equations with nonlocal boundary conditions

The determination of a space‐dependent source term along with the solution for a 1‐dimensional time fractional diffusion equation with nonlocal boundary conditions involving a parameter β>0 is considered. The fractional derivative is generalization of the Riemann‐Liouville and Caputo fractional derivatives usually known as Hilfer fractional derivative. We proved existence and uniqueness results for the solution of the inverse problem while over‐specified datum at 2 different time is given. The over‐specified datum at 2 time allows us to avoid initial condition in terms of fractional integral associated with Hilfer fractional derivative.     

2, 4-二氨基-6-（2’-吡啶基）均三嗪铜（Ⅱ）配合物的结构、抗菌活性及DNA作用

通过2,4-二氨基-6-(2′-吡啶基)均三嗪和高氯酸铜髤反应合成了一个配合物:[Cu(H2O)(PyTA)2](ClO4)2[PyTA=2,4-二氨基-6-(2′-吡啶基)均三嗪]。通过元素分析、红外光谱、紫外可见光谱、摩尔电导率和X-射线单晶衍射等方法对其进行了表征。结果表明该配合物晶体属单斜体,P21/c空间群,其晶体学参数:a=0.980 24(6)nm;b=1.248 31(7)nm,c=2.157 27(11)nm;β=108.657(3)°;Z=4,V=2.501 0(2)nm3,R1=0.054 3,wR2=0.1506。另外,应用试管二倍稀释法测定了配合物的抗菌活性,通过电子吸收光谱、荧光光谱、粘度测定及琼脂糖凝胶电泳等方法研究了配合物与DNA的作用。结果表明,与2,4-二氨基-6-(2′-吡啶基)均三嗪相比较,该配合物具有良好的抗菌活性,以插入模式与CT-DNA作用,并且在抗坏血酸存在下通过羟基自由基·OH切割pBR322DNA。     

Sensitive determination of methadone in human serum and urine by dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet followed by HPLC–UV

Dispersive liquid–liquid microextraction based on solidification of floating organic droplet was developed for the extraction of methadone and determination by high‐performance liquid chromatography with UV detection. In this method, no microsyringe or fiber is required to support the organic microdrop due to the usage of an organic solvent with a low density and appropriate melting point. Furthermore, the extractant droplet can be collected easily by solidifying it at low temperature. 1‐Undecanol and methanol were chosen as extraction and disperser solvents, respectively. Parameters that influence extraction efficiency, i.e. volumes of extracting and dispersing solvents, pH, and salt effect, were optimized by using response surface methodology. Under optimal conditions, enrichment factor for methadone was 134 and 160 in serum and urine samples, respectively. The limit of detection was 3.34 ng/mmL in serum and 1.67 ng/mL in urine samples. Compared with the traditional dispersive liquid–liquid microextraction, the proposed method obtained lower limit of detection. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high‐density and toxic solvents of traditional dispersive liquid–liquid microextraction method. The proposed method was successfully applied to the determination of methadone in serum and urine samples of an addicted individual under methadone therapy.     

基于模糊推理网的高层结构智能型式优化方法与系统

首先,给出了一种改进加权模糊推理网,建立了基于该推理网的结构性能评价过程与方法,该网兼有模糊综合评判、模糊推理与模糊推理网等算法共同优点;然后,给出了一种基于模糊综合评判的优选法,将其与六个目标级性能的评价网集成,形成了兼有性能评价与优选功能的集成推理网络系统,给出了该集成系统的网络结构图及其决策函数,同时,建立了基于上述方法的结构智能型式优化支持系统;最后,给出了工程实例,结果与实际吻合。实践表明:该方法能以直观的方式表征、存储与利用领域专家在型式优化时的知识与策略,并克服了传统基于模糊逻辑与神经网络的型式优化系统的不足,是解决具有多目标、多层次及不确定信息的型式优化问题的有效方法。