Chiral Phosphoric Acid Catalyzed Asymmetric Ugi Reaction by Dynamic Kinetic Resolution of the Primary Multicomponent Adduct

Reaction of isonitriles with 3‐(arylamino)isobenzofuran‐1(3H)‐ones in the presence of a catalytic amount of an octahydro (R)‐binol‐derived chiral phosphoric acid afforded 3‐oxo‐2‐arylisoindoline‐1‐carboxamides in high yields with good to high enantioselectivities. An enantioselective Ugi four‐center three‐component reaction of 2‐formylbenzoic acids, anilines, and isonitriles was subsequently developed for the synthesis of the same heterocycle. Mechanistic studies indicate that the enantioselectivity results from the dynamic kinetic resolution of the primary Ugi adduct, rather than from the C?C bond‐forming process. The resulting heterocycle products are of significant medicinal importance.     

高可靠分布式容错计算机架构的研究

分布式系统因其具有分散安装、可靠性高、扩展性好、维修成本低、健壮、安全等诸多优点,国内外相继开展分布式计算机高可靠性技术的研究。本文提出了高可靠分布式容错计算机的构架设计思路,并对TTE总线的选用进行了分析论证,重点描述了成员一致性保证和余度同步等关键技术。     

福寿螺的生活习性及养殖试验

本文介绍福寿螺的外部形态,生活习性,人工繁殖方法和越冬。     

Asymmetric 1,3-dipolar cycloaddition of nitrile oxides with optically active vinylboronic ester

Pinanyldioxy styrylboronic ester (1) was employed for asymmetric 1,3-dipolar cycloaddition with nitrile oxides, optically active △2-isoxazolines (3) or 4-hydroxy-△2-isoxazolines (4) were obtained. The effect of different bases on the selectivity of the cycloaddition reaction was studied.     

A micro-wave strategy for synthesizing room temperature phosphorescent materials

Room temperature phosphorescent(RTP) materials have a variety of applications ranging from bioimaging, optoelectronic devices to information security protection. However, the preparation procedures for these materials are always tedious and time-consuming. Here, we report a micro-wave approach to prepare RTP carbon dots(CDs) in only 8 min. The micro-wave promoted the carbon and boron bond formation using natural compounds glucose and boric acids. This result has been confirmed using TEM,FTIR, XP...     

煤气化可弃型催化剂

煤的高效催化气化技术是提高煤气化效率的重要途径。目前,除CaCO₃以外,其他碱金属、碱土金属与过渡金属类催化剂都由于成本较高、回收困难等问题并未广泛应用。可弃型催化剂具有廉价、不必回收、环保并兼有调节灰熔特性、固硫等优点,近年来在煤气化领域的研究和应用受到广泛关注。本文综述了国内外几类可弃型催化剂在煤气化领域的研究进展,包括钙基、工业废液、废渣和生物质灰等催化剂的催化特性及其机理,讨论了在实际应用中存在的问题,展望了未来煤气化可弃型催化剂的发展前景。     

二维正方晶格光子晶体平板的近场成像特性

光子晶体是由两种或两种以卜不同介电函数的材料周期性排列组成的一种人工晶体.由于介电甬数的周期性分布对入射光的调制作用,使得特定频率区域的人射光在光子晶体中传播时的群速度方向和相速度方向相反,因而使得光子晶体平板表现出负折射特性.系统研究了介质柱的形状对二维正方品格光子品体近场成像特性的影响.通过对分别由正方形、三角形、椭网形、长方形等形状介质柱组成的二维正方品格光子晶体平板近场成像特性的理论分析,发现当介质柱形状的对称性降低到一定程度后可以实现光子晶体近场成像的纵向平移.进一步通过对相应等频率曲线形状的分析,明确了光子晶体近场成像是由于自准直效应和负折射效应的共同作用形成的.     

Molecular hydrogen storage in Al-doped bulk graphite with wider layer distances

Molecular hydrogen storage at room temperature in Al-doped bulk graphite with wider layer distances was studied using density functional theory calculation. Hydrogen storage capacity of 3.48 wt% or volume density of 51 kg/m³ was predicted at T=300 K and P=0.1 GPa with adsorption energy E_b=?0.264 eV/H₂. This is close to the target of volume density 62 kg/m³ and satisfies the requirement of immobilization hydrogen with binding strength of 0.2–0.7 eV/H₂ at ambient temperature and modest pressure for commercial applications specified by the U.S. Department of Energy.     

基于PSD的微摆镜角度自准直测试系统设计

基于压电陶瓷的微摆镜是一种典型的二维角驱动部件,微摆镜系统的实用化需要进行微角度的测量,以便得到驱动电压与微偏转角之间的对应关系。设计了一种基于位置敏感探测器(PSD)的微摆镜角度测试系统,应用激光自准直原理,采用两次45°折返式结构,缩小了系统的体积并解决了传统折返式系统难以精准搭建的问题;采用多层前馈神经网络法对PSD进行了非线性校正,修正后整个系统的测量精度可达0.5″,测量范围为±400″。符合微摆镜角度测量的要求。     

基于原油配比混合实验的显微荧光光谱特征研究

显微荧光光谱已经成为流体包裹体系统测试分析中较为成熟的一项技术,可用于区分不同类型的原油与油包裹体,从而为研究含油气盆地的油气成藏历史提供重要依据。不同来源的原油在运聚的过程中可能会发生不同程度的混合作用,为了有效识别这一类地质过程,基于不同比例的原油配比混合实验,研究原油混合后的显微荧光光谱的具体变化特征。结果表明: 原油混源使得显微荧光光谱参数λ_max,QF-535和CIE-XY发生了非线性变化,具体表现为混源后原油的荧光光谱参数均介于两个端元油之间,混源油中某一端元油的比例越大,其荧光光谱参数越靠近这一端元油。在CIE-XY色品图中主要表现为非线性渐变的荧光颜色特征。光谱谱形的改变主要表现为谱形由“单峰型”变为“双峰型”和“三峰型”,同时主峰波长和次峰波长保留了两个端元油的信息;QF-535与混源比例可建立曲线用来定量计算两端元油的相对贡献度。综合上述荧光光谱参数和谱形的变化特征,利用原油和油包裹体的显微荧光分析,识别出东海盆地西湖凹陷A气田有三种不同类型原油充注,中间还发生了一次原油混源作用,即蓝绿色荧光原油和黄色荧光原油发生了混合,定量计算其混源程度为介于47%~55%。