蒙特卡洛法、离散传递法中的假散射与射线效应

本文构造了激光平行入射二维半透明介质的物理模型,研究了蒙特卡洛法、离散传递法中的假散射。通过分析 边界净热流研究了蒙特卡洛法、离散传递法中的射线效应。计算分析表明:蒙特卡洛法、离散传递法不存在假散射。蒙特 卡洛法不存在射线效应,离散传递法存在射线效应。在离散传递法中,随着射线数的增加,射线效应逐渐减少。     

Synthesis and Characterization of Amino-functionalized Meso-porous Silicate MCM-41 for Removal of Toxic Metal Ions

Amino-functionalized MCM-41 has been prepared by grafting amino containing functional groups onto mesoporous silicate MCM-41 and characterized by powder X-ray diffraction, N2 adsorption/desorption measurement, SEM, FT-IR, thermogravimetry and elemental analysis to confirm the ordered mesoporous structure and the functionalization of the amino groups. Sorption behavior for 18 metal ions on this sorbent has been studied and discussed.     

Phthalhydrazide immobilized on MCM‐41 as a potent and recoverable catalyst for the synthesis of pyrrolo[2,1‐a]isoquinolines

We present a study on the synthesis, characterization, and application of phthalhydrazide‐functionalized MCM‐41 (P‐MCM‐41) as a novel and efficient heterogeneous basic catalyst. The described catalyst was fully characterized via various techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X‐ray (EDX), X‐ray diffraction (XRD), and Fourier transform infrared (FT‐IR). P‐MCM‐41 efficiently catalyzed the four‐component reaction of arylaldehydes, Meldrum's acid, alkyl isocyanides, and isoquinoline in CHCl₃ to prepare pyrrolo[2,1‐a]isoquinolines in good yields.     

多芯片组件技术在航天光学遥感器中的应用

目前我国的光学遥感器的总体技术指标与国际先进水平还有较大差距,遥感图像的质量还比较低,大大制约了卫星遥感图像的应用发展。介绍了Multi-chip Module多芯片组件(MCM),它是20世纪90年代以来发展较快的一种先进混合集成电路技术,是实现电子装备小型化轻量化高速度高可靠低成本电路集成不可缺少的关键技术,此项技术在航天光学遥感器上的应用必将使中国的航天光学遥感器的研制水平提高到一个更高层次,使我国的航天遥感技术进入国际先进行列。     

Mesoporous Silica MCM‐41 Supported N‐Heterocyclic Carbene‐Pd Complex for Heck and Sonogashira Coupling Reactions

Heterocyclic carbene‐Pd complex was anchored onto the mesoporous silica MCM‐41 which exhibits high catalytic activity in Heck reaction under phosphine free reaction conditions for the reaction of iodo/bromoarenes with olefinic compounds such as butyl acrylate, isopropyl acrylate and styrene. This catalytic system also showed high activity for Sonogashira coupling reaction of various aryl halides under copper, phosphine and solvent‐free reaction conditions. The air and thermally stable catalyst were reused several times without significant loss of its activity. High efficiency of the catalyst along with its recycling ability and the rather low Pd‐loading demonstrated in both Heck and Sonogashira coupling reactions are the merits of the presented catalyst system.     

晶化温度对MCM-41结晶度、酸性和骨架铝结构的影响

选择硅酸钠－硫酸铝－十六烷基三甲基氯化铵体系,在水热条件下合成ＭＣＭ－４１中孔分子筛,采用ＸＲＤ、ＩＲ、ＮＨ３－ＴＰＤ、２７Ａｌ－ＭＡＳＮＭＲ进行了晶化温度与ＭＣＭ－４１分子筛结构和性能的关联研究．结果表明,在晶化温度为１５０℃时,ＭＣＭ－４１分子筛的结晶度最高;适当提高晶化温度,ＭＣＭ－４１分子筛呈现出酸性增加、四铝配位环境趋于规则和弱酸中心逐渐消失的规律．     

Ti-MCM-41催化剂的表面性质及介质极性对

用不同的铝源改性Ti MCM 41催化剂 ,得到了具有长程有序结构、n(Si) /n(Ti) =2 5的不同Si/Al比的改性Ti MCM 41.通过研究芳烃羟化反应随催化剂表面性质的变化规律发现 ,调变催化剂的表面性质 ,可控制反应物苯及目的产物苯酚与Al Ti MCM 41催化活性中心接近的程度 ,从而可实现对芳烃羟化反应化学选择性的控制 .介质极性对芳烃的化学亲和选择性也有影响 ,只有富含供电子氧原子且其极性大于苯的介质才有利于芳烃的羟化反应     

Introduction of Ag/CuO/MCM‐48 as an efficient catalyst for the one‐pot synthesis of novel pyran‐pyrrole hybrids

Bimetallic silver and copper incorporated mesoporous MCM‐48 (Ag/CuO/MCM‐48) was synthesized by simple wet‐impregnation method. The knowledge about its structural properties was gathered by means of Fourier transform‐infrared, energy‐dispersive X‐ray, X‐ray diffraction, field emission‐scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller analyses. The catalytic activity of Ag/CuO/MCM‐48 was examined in the one‐pot three‐component reaction of 3‐(1‐methyl‐1H‐pyrrol‐2‐yl)‐3‐oxopropanenitrile, malononitrile and various aromatic aldehydes leading to novel pyran‐pyrrole hybrid derivatives in reduced reaction times (5–10 min) and excellent yields (88–97%). Application of Ag/CuO/MCM‐48 as a potent heterogeneous catalyst with good reusability up to five times, use of ethanol as an eco‐compatible medium and chromatography‐free work‐up are some crucial green aspects of this procedure.     

Synthesis of Spiro‐dihydrofuran in the Presence of a Novel and Reusable Nanocatalyst Cu (II)‐Glycerol/MCM‐41

The use of supported Cu complex on mesoporous as a novel, efficient, heterogeneous, reusable and green catalyst for the synthesis of spiro‐dihydrofuran derivatives is reported. This methodology is effective for the reaction of dimedone with a wide range of aldehyde in the presence of BrCN and triethylamine. The structure of catalyst was characterized by different techniques such as EDX, SEM, TGA, ICP‐OES, XRD, TEM, FT‐IR, and BET. The recycled nanocatalyst was used at least five times with no significant loss of its activity.     

A phosphine‐free heterogeneous Suzuki–Miyaura reaction of aryl bromides catalyzed by MCM‐41‐supported tridentate nitrogen palladium complex under air

MCM‐41‐supported tridentate nitrogen palladium(II) complex [MCM‐41‐3 N‐Pd(II)] was conveniently synthesized from commercially available and cheap 3‐(2‐aminoethylamino)propyltrimethoxysilane via immobilization on MCM‐41, followed by reacting with pyridine‐2‐carboxaldehyde and PdCl₂. It was found that this palladium complex is an excellent catalyst for the Suzuki–Miyaura coupling reaction of aryl bromides on two points: (i) the use of 5 × 10⁻⁴ mol equiv. of MCM‐41‐3 N‐Pd(II) under air afforded the coupling products efficiently after easy workup; (2) the catalyst can be reused many times without loss of catalytic activity. Copyright © 2011 John Wiley & Sons, Ltd.