Design of CASSEGRAIN telescope baffles with honeycomb entrance

The stray radiation suppression in Cassegrain family optical system is presented. The design method for ultra-short outer baffle with honeycomb structure is proposed. Meanwhile the constraint formulas for designing the geometries of primary baffle and secondary baffle are deduced when basing the characteristic and taking vignette into account. According to the ray trace simulated data, the point source transmit- tance values of the baffle are less than 10-^10 when incident angles are larger than the rejection angle. The honeycomb-look front baffle guarantees a comparable performance of stray light suppression with traditional tube baffle, while reducing the size greatly.     

A Novel Method for One‐pot Synthesis of Furo[3,2‐c]coumarin Derivatives from 4‐Hydroxycoumarin and Arylglyoxal under Microwave Irradiation

A novel one‐pot synthesis of furo[3,2‐c]coumarins has been developed from readily available starting materials 4‐hydroxycoumarin and arylglyoxal. This method is simple, rapid and good yielding.     

POINTWISE ESTIMATE OF SOLUTIONS OF ISENTROPIC NMIER-STOKES EQUATIONS IN EVEN SPACE-DIMENSIONS

1 IntroductionIn this paPer, we are interested in tlie time-asymptotic behavior of solutions to isentropicNavier-stokes equations in even space-dimensions. Recently many people began to study it'sasymptotic behavier when time is large enough. This can be manifested in tlie after refer-ences. For the pointwise estimate of solution to generaJ hyperbolic-parabolic systems in onespace dimension see Liu and Zeng[']. In several space variables, Kawashima[31 has studiedgeneral hyperbolic-parabolic…     

MCNOs/CdS双效光催化剂的制备及其性能研究

水热合成法制备了不同磁性纳米洋葱碳(MCNOs)负载量(0%、1%、3%、5%)的MCNOs/CdS光催化剂。并通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、X射线光电子能谱(XPS)、紫外可见光光谱(UV-Vis)、磁滞回线测定仪(VSM)对其进行表征,探究了MCNOs负载比例对催化剂在可见光下降解RhB性能及机理的影响。结果表明,MCNOs能有效提高CdS的光催化效果,复合3%MCNOs后降解率为96%,与纯CdS相比降解率提高了30%,磁性分析表明,其具有良好的顺磁性并能实现催化剂的有效回收。MCNOs/CdS在可见光下催化降解RhB的一级反应动力学直线有较好的拟合度,表明制备的催化剂有较好的催化活性。     

测不准原理与Cauchy问题的唯一性

本文讨论具非光滑特征的二阶椭圆偏微分算子Cauchy问题的唯一性.借用测不准原理的思想,通过将方程的解的精细微局部分解,把唯一性证明中最关键的Carleman估计在微局部的层次展开,从而可以在相差一个低阶项的意义下“凝固”某些奇异点的系数,克服因非光滑特征带来的困难,在较以往文章更一般的条件下证明了二阶椭圆微分算子Cauchy 问题的唯一性.     

Photocatalytic aerobic cross-coupling reaction of N-substituted anilines with N-aryl glycine esters: Synthesis of α-aryl α-amino esters

A novel photocatalytic cross dehydrogenative coupling reaction of N-aryl glycine esters with N-substituted anilines has been developed. The reaction proceeds effectively using methylene blue as a photocatalyst under visible light irradiation without any metal, chemical oxidant or additive. A variety of α-aryl α-amino derivatives were prepared in moderate to excellent yields with a high para-regioselectivity.     

Interaction of shock and conormal singularities for conservation laws

In this paper, we use the technique of tangential paradifferential operator, which defined on the space of conormal distribution with three indices, to deal with the interaction of a multi-dimensional shock and a progressing wave of weak conormal singularities.     

Preparation and photocatalytic performance research of Bi2WO6/UiO-66-NH2 composite

Bi₂WO₆/UiO-66-NH₂ photocatalysts were fabricated through solvothermal method using acetic acid as template. The photocatalytic performance of as-fabricated composites was highly improved under simulated visible light due to the addition of UiO-66-NH₂. The structural and chemical properties of the composites were characterized through FTIR, XRD, XPS, SEM, BET, UV–vis DRS and PL. After 90 min of visible light irradiation, the RhB at an initial concentration of 10 mg·L^?1 in the solution was degraded by 99.4% due to the addition of 10 mg of the composite. There was no significant decrease in the photocatalytic activity even after four rounds of cycles. The free radical capture experiments indicate that the photogenerated holes (h⁺) were the main active sites. The possible photocatalytic degradation mechanism was proposed as the specific surface area of the composite was enlarged due to the uniform distribution of UiO-66-NH₂ on the surface of Bi₂WO₆. The electron–hole pairs recombination rate was decreased due to the photogenerated electrons (e^?) on the CB of Bi₂WO₆ which can be rapidly transferred to the CB of UiO-66-NH₂ and the photogenerated holes of UiO-66-NH₂ transferred to the VB of Bi₂WO₆. Meanwhile, the RhB was directly oxidized to H₂O and CO₂ by h⁺ to achieve the purification effect.

     

Nonlinear evolution systems and green's function

In this paper, we will introduce how to apply Green's function method to get the pointwise estimates for the solutions of Cauchy problem of nonlinear evolution equations with dissipative structure. First of all, we introduce the pointwise estimates of the time-asymptotic shape of the solutions of the isentropic Navier-Stokes equations and show to exhibit the generalized Huygen's principle. Then, for other nonlinear dissipative evolution equations, we will only introduce the result and give some brief explanations. Our approach is based on the detailed analysis of the Green's function of the linearized system and micro-local analysis, such as frequency decomposition and so on.     

Palladium-catalyzed hydroarylation of alkynes with arylboronic acids

Reaction of symmetrical and unsymmetrical alkynes with arylboronic acids, using PdCl₂ as catalyst source and i-Pr₂NPPh₂ as ligand, afforded trisubstituted alkenes with regioselectivity in good to excellent yields without a common additional acetic acid. Its efficiency has been demonstrated by its good functional groups, high yield and crowded substrates.