Bi_2SiO_5半导体光催化剂

Bi基半导体光催化剂具备独特的电子能带结构、可调节与可拓展的光谱响应范围、低毒及组成元素供给丰富等优点,使其成为高效、可实用型光催化剂的重要候选者。而Bi基非金属氧酸盐作为新型半导体光催化剂,其非金属氧酸根的表面修饰作用及高结晶性使其呈现出更加独特的光催化活性。本文简要介绍了Bi基半导体光催化剂的结构特性及近几年的研究进展,重点综述了Bi基非金属氧酸盐的一员——Bi_2SiO_5及其制备、异质结的构建和电子能带结构的研究进展,并对其今后的研究与应用方向作了进一步的展望。     

Extinction Effects of Multiplicative Non-Gaussian L′evy Noise in a Tumor Growth System with Immunization

The extinction phenomenon induced by multiplicative non-Gaussian Levy noise in a tumor growth model with immune response is discussed. Under the influence of the stochastic immune rate, the model is analyzed in terms of a stochastic differential equation with multiplicative noise. By means of the theory of the infinitesimal generator of Hunt processes, the escape probability, which is used to measure the noise-induced extinction probability of tumor cells, is explicitly expressed as a function of initial tumor cell density, stability index and noise intensity. Based on the numerical calculations, it is found that for different initial densities of tumor cells, noise parameters play opposite roles on the escape probability. The optimally selected values of the multiplicative noise intensity and the stability index are found to maximize the escape probability.     

NiMo 催化剂上MoS2 形貌与其DBT 加氢脱硫选择性的关系

制备了两个系列不同镍钼负载量的NiMo 催化剂,并用X 衍射、N2 物理吸附和透射电镜进行了表征。以二苯并噻吩
为模型硫化物,在高压固定床微型反应器上对该NiMo 催化剂的加氢脱硫性能进行了评价,研究了MoS2 形貌与催化剂加氢脱
硫选择性之间的关系。结果表明,镍钼负载量对MoS2 形貌有明显的影响。Mo18Ni4 催化剂(含18% MoO3 和4% NiO)上
MoS2 呈多级层状结构,具有较高的加氢脱硫活性和优异的加氢脱硫选择性。加氢选择性与催化剂上活性组分MoS2 的堆积层
数相关联呈很好的线性关系;堆积层数越多,其加氢选择性也越高。     

磷钼酸和钛硅纳米复合氧化物构筑高活性氧化脱硫催化剂

采用溶胶凝胶法合成了钛硅纳米复合氧化物(Ti O_2-Si O_2),并以其为载体用原位合成技术或浸渍法负载Keggin结构磷钼酸(HPMo)制备了复合催化剂,使用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)、紫外可见光谱仪(UV-Vis)、X射线衍射光谱(XRD)和比表面分析仪(BET)等测试手段对催化剂的结构进行表征。结果表明,采用原位法合成的催化剂为纳米粒子,纳米晶骨架内存在微孔和介孔共存的孔道结构。原位合成技术或浸渍法制备的催化剂中HPMo保持Keggin骨架结构。以模拟油品(二苯并噻吩、苯并噻吩或噻吩的正辛烷溶液)的氧化脱硫为探针反应,在选定的条件下:硫含量为200.0 g/g的正辛烷溶液和无水乙醇各10.0 m L,反应温度60℃,催化剂质量0.15 g,n(H_2O_2)∶n(S)=5∶1,二苯并噻吩的脱除率高于96.0%,产物中硫含量低于10.0μg/g。在相同的实验条件下,受电子云密度的影响,脱硫由易到难的顺序为二苯并噻吩苯并噻吩噻吩。催化剂循环使用4次后活性未见明显降低,是一类绿色的模型有机硫化物氧化脱除工艺用催化剂。     

Upper bound for the time derivative of entropy for a stochastic dynamical system with double singularities driven by non-Gaussian noise

A stochastic dynamical system with double singularities driven by non-Gaussian noise is investigated.The Fokker-Plank equation of the system is obtained through the path-integral approach and the method of transformation.Based on the definition of Shannon’s information entropy and the Schwartz inequality principle,the upper bound for the time derivative of entropy is calculated both in the absence and in the presence of non-equilibrium constraint.The present calculations can be used to interpret the effects of the system dissipative parameter,the system singularity strength parameter,the noise correlation time and the noise deviation parameter on the upper bound.     

硫化镉纳米粒子的合成及荧光猝灭法测定Cu 2+的初步研究

以淀粉为包裹剂,硫脲为硫源,通过简单且“绿色”的途径,在水溶液中成功地合成了淀粉包裹的CdS纳米粒子。研究了纳米粒子的大小,不同的硫源、pH值、反应时间等条件因素对其吸收光谱和荧光光谱特性的影响,并以该纳米粒子作为荧光探针,初步探讨了痕量铜离子对其的荧光猝灭作用。结果表明:在最佳实验条件下,在2.0~50μg/L测定区间内铜离子呈现良好的线性(r=0.9986),证明该方法灵敏度高且简便易行,有望进一步开发其在生物样品微量元素分析中的应用。     

一种集成式石英谐振加速度计信号处理与融合方法

谐振式加速度计能够将加速度直接转化为稳定的频率信号,可以获得优良的性能。针对目前石英谐振加速度计灵敏度偏低,以及温度变化等因素引起的频率漂移等难题,提出了一种基于多电极谐振器的集成式石英加速度计的信号处理与融合的方法。集成式石英加速度计输出多路谐振信号,形成差频信号,融合后可以得到高精度的数字信号,设计了基于FPGA的电路实现方案。通过实验测试结果,输出数据响应时间为125 ms的条件下,传感器标度因数从传统的100 Hz/g以下提升到1742.5 Hz/g,线性相关系数为R~2=0.9985。提出的信号处理与融合方法具有较高的信号处理实时性,显著提高了石英谐振加速度计的灵敏度,可以应用于集成式石英谐振加速度计数据信号处理以及实时测量系统中。     

硫酸氢钠催化合成14-烷基(芳基)-14H-二苯并[a,j]氧杂蒽类化合物

以β-萘酚,芳醛为原料,硫酸氢钠为催化剂,在无溶剂条件下合成了8个14-烷基(芳基)-14H-二苯并[a,j]氧杂蒽类化合物,其结构经1H NMR和IR表征。     

Isophorone－based Fluorescent Dopant for Red Organic Electrolumi－nescence Device

lsophorone-based red fluorescent compound 3-(dicyanomethy-lene ) -5, 5-dimethyi- 1- [ 2- ( N-ethyl-3-carbazyi ) ethylene ] cyciohe-xene (DCDCC) was synthesized for use in organic Hght-emit-ring diodes (OLEDs). DCDCC was characterized by narrow emission in photoluminescence with full.width at half-maximum of only 50 nm in solution and in thin solid film of 70 nm width. devices with configuration of ITO/NPB/Alq3:DCDCC/Alq3/Mg: Ag were fabricated utilizing DCDCC as dopant emitter. An efficient red emission peaked at 612 nm was obtained for the device with 1% (wt.%) DCDCC in Alq3. The maximum luminance and current efficiency were as high as 3700 cd/m^2 at 14 V and 1.25 cd/A at 150 mA/cm^2, respective-ly.