New photocatalyst BiOCl/BiOI composites with highly enhanced visible light photocatalytic performances

BiOCl/BiOI composites with a visible light response were prepared by a simple hydrothermal method. Even though both single BiOCl and BiOI show low photocatalytic activity, BiOCl/BiOI composites provide enhanced efficiency in decomposing organic compounds including Methyl Orange (MO) and Rhodamine B (RhB). Furthermore, the 20%BiOCl/BiOI composite shows the highest efficiency for decomposing MO, while the highest performance is observed for the degradation of RhB over 70%BiOCl/BiOI composite. A possible photocatalytic mechanism has been proposed based on the relative experiments and the band positions of BiOCl and BiOI.     

A covalently-linked microporous organic-inorganic hybrid framework containing polyhedral oligomeric silsesquioxane moieties

By a Yamamoto-type of Ullmann cross-coupling reaction, a well-defined covalently-linked microporous organic-inorganic hybrid framework polyoctaphenylsilsesquioxane (JUC-Z1) was effectively prepared from the nano building block p-iodio-octaphenylsilsesquioxane (I8OPS) with a yield of ca. 100%. The structure of JUC-Z1 was characterized by (13)C CP/MAS NMR and (29)Si MAS NMR experiments. Fourier transform infrared spectroscopy (FTIR) was performed to confirm the presence of functions in the framework. The results showed that inorganic silsesquioxane cubes were linearly covalently-linked by biphenyls, offering a highly cross-coupling framework. The powder X-ray diffraction (PXRD) pattern and transmission electron microscope (TEM) image show that JUC-Z1 is spherical with uniform micropores. N(2) adsorption results suggest that the hybrid framework has a narrow pore size distribution from 11.8 to 20.0 ?, with a BET surface area of 283 m(2)g(-1) and a pore volume of 0.226 cm(3)g(-1). A thermogravimetric (TG) analysis indicates the thermal stability of JUC-Z1 up to 397 °C in air. Moreover, a liquid sorption experiment reveals the favorable sorption of benzene and water.     

Retention behaviors of natural products in reversed-phase liquid chromatography using mobile phase comprising methanol, acetonitrile and water

The three-component mobile phase, methanol-acetonitrile-water, has been frequently used for the separation of natural products in complicated herbal extracts by reversed-phase liquid chromatography, especially when two-component solvent systems do not work. However, the rational for optimization of this three-solvent system is not clear, so far. In this study, the retention behavior of different types of natural products in RP-LC with a methanol-acetonitrile-water elution system was studied. A total of 27 compounds from four classes, including steroids, flavonoids, phenolic acids, and triterpene saponins were analyzed by high-performance liquid chromatography coupled with mass spectrometry or ultraviolet detectors. It was interesting to find that prolonged retention times and improved separation capabilities were obtained when the acetonitrile-to-methanol ratio was 3-16%. This rule applied to all four classes of natural products under different instrumental conditions, and could be valuable for the separation of natural products in complicated samples.     

Detecting small lung tumors in mouse models by refractive-index microradiology

Refractive-index (phase-contrast) radiology was able to detect lung tumors less than 1 mm in live mice. Significant micromorphology differences were observed in the microradiographs between normal, inflamed, and lung cancer tissues. This was made possible by the high phase contrast and by the fast image taking that reduces the motion blur. The detection of cancer and inflammation areas by phase contrast microradiology and microtomography was validated by bioluminescence and histopathological analysis. The smallest tumor detected is less than 1 mm(3) with accuracy better than 1 × 10(-3) mm(3). This level of performance is currently suitable for animal studies, while further developments are required for clinical application.     

Two-body threshold spectral analysis, the critical case

We study in dimension d?2 low-energy spectral and scattering asymptotics for two-body d-dimensional Schrödinger operators with a radially symmetric potential falling off like −γr−2, γ>0. We consider angular momentum sectors, labelled by l=0,1,…, for which γ>²(l+d/2−1). In each such sector the reduced Schrödinger operator has infinitely many negative eigenvalues accumulating at zero. We show that the resolvent has a non-trivial oscillatory behaviour as the spectral parameter approaches zero in cones bounded away from the negative half-axis, and we derive an asymptotic formula for the phase shift.     

Semi-varying coefficient models with a diverging number of components

Semiparametric models with both nonparametric and parametric components have become increasingly useful in many scientific fields, due to their appropriate representation of the trade-off between flexibility and efficiency of statistical models. In this paper we focus on semi-varying coefficient models (a.k.a. varying coefficient partially linear models) in a “large n, diverging p” situation, when both the number of parametric and nonparametric components diverges at appropriate rates, and we only consider the case p=o(n). Consistency of the estimator based on B-splines and asymptotic normality of the linear components are established under suitable assumptions. Interestingly (although not surprisingly) our analysis shows that the number of parametric components can diverge at a faster rate than the number of nonparametric components and the divergence rates of the number of the nonparametric components constrain the allowable divergence rates of the parametric components, which is a new phenomenon not established in the existing literature as far as we know. Finally, the finite sample behavior of the estimator is evaluated by some Monte Carlo studies.     

EXISTENCE OF PERIODIC SOLUTIONS FOR A DIFFERENTIAL INCLUSION SYSTEMS INVOLVING THE p（t）-LAPLACIAN

We study a nonlinear periodic problem driven by the p(t)-Laplacian and having a nonsmooth potential (hemivariational inequalities). Using a variational method based on nonsmooth critical point theory for locally Lipschitz functions, we first prove the existence of at least two nontrivial solutions under the generalized subquadratic and then establish the existence of at least one nontrivial solution under the generalized superquadratic.     

Parallel identical machines scheduling with deteriorating jobs and total absolute differences penalties

In this paper we consider parallel identical machines scheduling problems with deteriorating jobs. In this model, job processing times are defined by functions of their starting times. We concentrate on two goals separately, namely, minimizing the total absolute differences in completion times (TADC) and the total absolute differences in waiting times (TADW). We show that the problems remains polynomially solvable under the proposed model.     

多周期多目标条件风险值模型

在商业、工业、电力和房地产等行业中存在许多复杂的多周期风险决策问题,它的数学模型研究对于解决这些问题具有重要的作用.作者建立了一种新的多周期多目标条件风险值(CVaR)数学模型理论和方法.先定义了一种带时间段的多周期多目标损失函数下的α-VaR和α-CVaR值,给出了一类多周期多目标CVaR最优化模型.然后,证明了多目标意义下的对应模型的等价定理,给出了多周期多目标CVaR模型的近似求解等价模型.最后,建立了一种生产企业在供过于求和供不应求两种情形下产生的多周期双目标CVaR模型,针对一个电力生产企业进行的数值实验,表明了模型可以得到在最小供给的用电损失分布下的各周期下的相匹配供电策略,可以帮助供电部门各个时期供电不平衡状况下的风险控制.     

Rational design of 3D dendritic TiO2 nanostructures with favorable architectures

Controlling the morphology and size of titanium dioxide (TiO(2)) nanostructures is crucial to obtain superior photocatalytic, photovoltaic, and electrochemical properties. However, the synthetic techniques for preparing such structures, especially those with complex configurations, still remain a challenge because of the rapid hydrolysis of Ti-containing polymer precursors in aqueous solution. Herein, we report a completely novel approach-three-dimensional (3D) TiO(2) nanostructures with favorable dendritic architectures-through a simple hydrothermal synthesis. The size of the 3D TiO(2) dendrites and the morphology of the constituent nano-units, in the form of nanorods, nanoribbons, and nanowires, are controlled by adjusting the precursor hydrolysis rate and the surfactant aggregation. These novel configurations of TiO(2) nanostructures possess higher surface area and superior electrochemical properties compared to nanoparticles with smooth surfaces. Our findings provide an effective solution for the synthesis of complex TiO(2) nano-architectures, which can pave the way to further improve the energy storage and energy conversion efficiency of TiO(2)-based devices.