New synthetic way to prepare 2-aryl-8-(piperidin-4-yl)-5,7-dimethoxy-4H-chromen-4-one as key intermediate for CDK inhibitor

As an important intermediate to study cyclin-dependent kinase(CDK)inhibitors,2-aryl-8-(piperidin-4-yl)-5,7-dimethoxy-4H- chromen-4-one derivatives were prepared usingβ-diketone route with low yield.In our study,chalcone route has been investigated and the result suggested that the benzaldehydes substituted with electron-donating group give much better yield thanβ-diketone route.This new method will be an efficient way to start further research on new anticancer flavonoids.     

计算机联锁控制系统的进路生成算法研究

提出了一种有效分解车站站场图形的方法．构造出由股道区段组成的子集链．在此基础上进路生成问题转化为变约束条件的优化问题．通过对子集的处理消除了约束条件．给出了适于生成进路的遗传算法．理论分析及仿真实验结果表明给出的进路生成算法的有效性及实用性．     

最小费用原则下的运输路径选择

论述了运输费用的内涵及其构成。运输费用主要包括劳务费、过路费、燃油费、轮胎费，研究了这几种费用的计算方法。并且以吉林省吉林市为起点，以桦甸市为终点，遵循费用最小的原则，分析了运输路径的最佳选择，同时对路径选择的可能原因作出了定性解释。     

一类3-连通图上的最优容错路由选择的构成

一类３－连通图上的最优容错路由选择的构成郑晓罗予频杨士元（南京广播电视大学，南京２１００２９）（清华大学自动化系，北京１０００８４）在描述某网络的图中，给各有序的两点定义一条称之为路由（ｒｏｕｔｅ）的通信路径，这就构成了ｒｏｕｔｉｎｇ。当故障发生时...     

Controlled Synthesis of CdClOH Sub-nanocones by Low-temperature Solution Process and Their Transformation into CdS Hollow Sub-nanocones

Novel CdClOH sub‐nanocone crystals were successfully synthesized on a large scale by a facile solution‐based method using polymers as crystal growth modifiers. The crystals showed cone‐like morphology. Some factors affecting the morphology and size of the product, such as reaction temperature, concentrations of polyacrylamide (PAM), and pH value of the solution, were systematically studied. Experiments implied that polymer PAM played a key role in the formation of CdClOH sub‐nanocones. A possible formation mechanism of CdClOH sub‐nanocones was suggested based on nucleation‐etching process‐recrystallization in a mild aqueous solution. Furthermore, the as‐prepared CdClOH sub‐nanocones could be further transformed into CdS hollow sub‐nanocones by an anion‐exchange reaction.     

基于特征单元的设备选型状态空间理论与方法

提出零件特征单元加工过程的状态空间理论,并将之用于解决零件加工的工艺设备选型问题.基于复杂零件特征具有多样性和复合性的特点,定义特征单元,以便于分析零件特征.针对单一特征单元,提取特征单元加工前和加工后两个状态,通过分析两个状态变换原因,构建状态变换矩阵,得出状态变换矩阵代表工艺设备加工能力的结论.通过构建状态变换方程描述加工过程.建立状态空间,将工艺设备选型问题转换为加工前和加工后两个状态在状态空间中的路径规划问题.在实际生产的约束条件下,将状态空间中路径规划问题转化为现有工艺路线的优化问题,并且建立工艺设备选型优化模型,优选出较理想的工艺路线,从而选出与该条工艺路线对应的一套工艺设备.应用算例验证了该方法的可行性.     

考虑实时路况的出行路线选择模型

为了缓解交通拥堵问题,本文在现有的导航仪基础上,考虑到道路的实时情况,设计新的导航仪,帮助居民选择出用时最短且能尽量避免拥堵的路线。研究主要包括两方面：首先,在存在不拥堵路线的情况下,利用最大流模型计算出道路流量,结合实际流量,在尽量避免拥堵(实际流量不超过最大流量)的情况下,求出最短路程,给出建议。然后,考虑拥堵问题难以避免,加强了与实际道路状况的联系,对道路出行选择模型进行了优化,先将道路分为非常拥堵、存在拥堵、畅通三种情况,然后再根据道路实时流量,利用G-LN的模型计算出车道的速度,结合路程,找出用时最短的路线。     

盐酸法制备低氟含量饲料级磷酸氢钙的工艺研究

在不添加任何除氟剂的条件下,用盐酸浸取磷矿,通过调整工艺参数和采用特殊的试验条件,制备了低氟含量饲料级磷酸氢钙;着重探讨了盐酸浓度、反应时间、静置时间、温度、鼓气速率等因素对磷酸氢钙中氟含量的影响.结果表明,在盐酸溶解过程中减少氟的溶出,有利于在反应中同步降低氟含量;得到的磷酸经简单的过滤、中和,可用于制备氟含量低达0.1%(低于国家标准0.18%)的饲料级磷酸氢钙.     

Facile solvothermal synthesis of graphene-MnOOH nanocomposites

In this paper, we report a facile solvothermal route capable of aligning MnOOH nanocrystals on graphene. X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations indicate that the exfoliated graphene sheets are decorated randomly by MnOOH nanocrystals, forming well-dispersed graphene-MnOOH nanocomposites. Dissolution-crystallization and oriented attachment are speculated to be the vital mechanisms in the synthetic process. The attachment of additives, such as MnOOH nanoparticles, are found to be beneficial for the exfoliation of GO as well as preventing the restack of graphene sheets. Moreover, cyclic voltammetry (CV) analyses suggest that the electrochemical reversibility is improved by anchoring MnOOH on graphene. Notably, the as-fabricated nanocomposites reveal unusual catalytic performance for the thermal decomposition of ammonium perchlorate (AP) due to the concerted effects of graphene and MnOOH. This template-free method is easy to reproduce, and the process proceeds at a low temperature and can be readily extended to prepare other graphene-based nanocomposites.     

Mechanoluminescence and thermoluminescence of Mn doped ZnS nanocrystals

This paper reports the synthesis of ZnS:Mn nanocrystals by the chemical route in which mercaptoethanol was used as the capping agent. The particle size of such nanocrystals was measured using XRD and TEM patterns and was found to be in between 3and 5 nm. It was found that the peak position of TL glow curve and the TL intensity of ZnS:Mn nanoparticles increases as the particle size is decreased. The isothermal decay technique is used to determine the trap-depth. The stability of the charge carriers in the traps increase with the decrease in size of the nanoparticles. The higher stability may be attributed to the higher surface/volume ratio and also to the increase in the trap-depth with decreasing particle size. When a ZnS:Mn nanocrystal is deformed the peak intensity I_m increases linearly with the increasing height of the load. After I_m, initially the ML intensity decreases at a fast rate, and later on it decreases at a slow rate. The ML in ZnS:Mn nanocrystals can be understood on the basis of the piezoelectrically induced electron detrapping model.