摘要：激发态双质子转移反应长期困扰着理论和实验科学家并成为了一个悬而未决的热点问题.本文利用完全活化空间自洽场方法及其二阶微扰理论(MS-CASPT2//CASSCF)系统地研究了典型体系1,8-羟基-2-萘甲醛(DHNA)的激发态双质子转移反应以及相关的激发态弛豫过程.在MS-CASPT2//CASSCF水平下,本文优化了三个能量相近但结构不同的Si态互变异构体,即S1-ENOL、S1-KETO-1和S1-KETO-2,以及两个关键的S_(1)/S_(0)锥形交叉点结构,即S1SO-KETO-1和S1SO-KETO-2.其中,两个极小点S1-KETO-1和S1-KETO-2与实验上观测到的双荧光发射现象密切相关.本文还利用MS-CASPT2//CASSCF方法计算了双质子转移反应的二维势能面以及从极小点到交叉点结构的线性内插路径;相应计算结果证实了DHNA体系具有分步的激发态双质子转移机制.具体来说,从S1-ENOL到S1-KETO-1的第一个质子转移过程是无能垒的,而从S1-KETO-1到S1-KETO-2的第二个质子转移过程则需要克服一个大约6.0kcal/mol的能垒.此外,由于从S1-KETO-1(S1-KETO-2)到S1SO-KETO-1(S1SO-KETO-2)的线性内插路径显示DHNA体系需要翻越一个约为12.0 kcal/mol的能垒,因此DHNA体系将在S_(1)态上停留一段时间并发生双荧光发射现象.当然,S_(1)/S_(0)锥形交叉点也会促使DHNA体系从S_(1)态内转换到S_(0)态,而这会一定程度上降低DHNA体系发射荧光的效率.可以通过限制C5-C8-C9-O10二面角旋转来降低体系的内转换效率,进而提高DHNA体系的发光效率.本工作不仅有助于理解激发态双质子转移机制,还有助于设计具有优异发光性能的新型分子材料.

摘要：In 2005, Bao, et al. [Appl. Math. and Comput., vol.169, No.2, 2005] showed that Tzeng, et al.’s nonrepudiable threshold multi-proxy multi-signature scheme with shared verification was insecure, and proposed an improved scheme with no Share Distribution Center (SDC). This paper shows that Bao, et al.’s scheme suffers from the proxy relationship inversion attack and forgery attack, and pro- poses an improvement of Bao, et al.’s scheme.

摘要：人类毛发红素(HTC)是一类生物安全性高、环境友好、性能稳定的天然色素,然而HTC的核心结构BBTD在溶解状态和固态下均无荧光发射.通过结构测试结合理论计算,我们揭示了该化合物独特的双重暗态光物理特性的内在机理.在深刻理解机理的基础上,我们利用化学修饰的手段改造了BBTD母核,设计合成了一系列具有聚集诱导发射光性质的BBTD衍生物,并成功将其应用于溶酶体靶向成像以及DN A定量检测领域.

摘要：Due to the increasing global demand for industrial gas, the development of large-scale cryogenic air separation systems has attracted considerable attention in recent years. Increasing the height of the adsorption bed in a vertical radial flow adsorber used in cryogenic air separation systems may efficiently increase the treatment capacity of the air in the adsorber. However, uniformity of the flow distribution of the air inside the adsorber would be deteriorated using the height-increasing method. In order to reduce the non-uniformity of the flow distribution caused by the excessive height of adsorption bed in a vertical radial flow adsorber, a novel parallel connection method is proposed in the present work. The experimental apparatus is designed and constructed; the Computational Fluid Dynamics(CFD) technique is used to develop a CFD-based model, which is used to analyze the flow distribution, the static pressure drop and the radial velocity in the newly designed adsorber. In addition, the geometric parameters of annular flow channels and the adsorption bed thickness of the upper unit in the parallelconnected vertical radial flow adsorber are optimized, so that the upper and lower adsorption units could be penetrated by air simultaneously. Comparisons are made between the height-increasing method and the parallel connection method with the same adsorber height. It is shown that using the parallel connection method could reduce the difference between the maximum and minimum radial static pressure drop by 86.2% and improve the uniformity by 80% compared with those of using the height-increasing method. The optimal thickness ratio of the upper and lower adsorption units is obtained as 0.966, in which case the upper and lower adsorption units could be penetrated by air simultaneously, so that the adsorbents in adsorption space could be used more efficiently.

摘要：为了提高产品智能设计过程中设计知识的使用效率和质量,有必要向设计人员主动推送设计知识。知识推送主要包括知识匹配和匹配结果的合理推送两个方面。针对现有知识匹配通常缺乏智能性和匹配结果推送缺少个性化的问题,提出基于适用概率匹配和多维情境驱动的设计知识推送技术。构建包括设计知识表示向量、设计案例特征向量和映射布尔矩阵等的训练样本集,通过贝叶斯理论计算设计知识适用与不适用于设计内容的概率,即二者之间的匹配度,得到推送知识集。构建等级化设计内容模型对推送知识集进行过滤,通过设计知识、设计上下文、设计内容和设计人员等多维情境驱动,实现个性化的设计知识推送。在数控机床智能设计平台中的知识推送应用,证明了该技术的可行性和正确性。

摘要：二维有机-无机杂化钙钛矿因在光伏、光电子等领域的巨大应用潜力而备受关注.此外,该类材料具有突出的结构可调性和材料稳定性,为功能性质的设计调控及器件应用提供了丰富的材料设计平台.然而,将多种物理通道的性质整合实现材料的多功能性仍具有挑战性,而对其进行快速有效的调节更是难上加难.迄今为止,尚未成功实现可调谐的光电多通道响应材料.本文成功开发了一种简便有效的机械力化学合成方法,可实现二维杂化钙钛矿中的多功能光电集成和调控.温和的外部机械刺激可快速形成锰掺杂的二维杂化钙钛矿(Cyclopropylammonium)2Pb(1-x)MnxBr4,并迅速调节其光学性质并诱导高温介电开关,实现高效的蓝色、白色、粉红色和橙色荧光特性.这项工作将为多功能光电响应材料的快速有效设计提供新的视角,也将为低成本、高效率智能设备的进一步开发和应用提供新的机遇.

摘要：Levulinic acid(LA) has been identified as a promising green,biomass derived platform *** surface analysis(RSA) with a four-factor-five-level central composite design(CCD) was applied to optimize the hydrolysis conditions for the conversion of bamboo(Phyllostachys Praecox ***) shoot shell(BSS) to LA catalyzed with ionic liquid [C4mim]*** effects of four main reaction parameters including temperature,time,C[C4mim]HSO4(initial [C4mim]HSO4 concentration) and XBSS(initial BSS intake) on the hydrolysis reaction for yield of LA were analyzed.A quadratic equation model for yield of LA was established and fitted to the data with an R2 of 0.9868,and effects of main factors and their corresponding relationships were obtained with *** validation and results of CCD showed good correspondence between actual and predicted *** analysis of variance(ANOVA) of the results indicated that the yield of LA in the range studied was significantly(P<0.05) affected by the four *** optimized reaction conditions were as follows:temperature of 145 ℃,time of 103.8 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2.04%(by mass),respectively.A high yield [(71±0.41)%(by mol),triplicate experiment] was obtained at the optimum conditions of temperature of 145 ℃,time of 104 min,C[C4mim]HSO4 of 0.9 mol.L-1 and XBSS of 2%(by mass),which obtained from the real experiments,concurred with the model prediction [73.8%(by mol) based on available C6 sugars in BSS or 17.9%(by mass) based on the mass of BSS],indicating that the model was adequate for the hydrolysis process.

摘要：Drug resistance is one of the major obstacles in the drug therapy of *** in this area in pre-clinical research have focused on developing novel platforms to evaluate and decrease drug *** this paper,inspired by the structure of hives where swarms live and breed,we propose porous hydrogel arrays with a uniform pore structure for the generation of hepatoma cell spheroids and the investigation of drug *** porous hydrogel arrays were fabricated using polyeth-ylene glycol diacrylate(PEGDA)hydrogel to negatively replicate a well-designed *** from the elaborate processing of the template,the prepared porous hydrogel arrays possessed a uniform pore *** to their anti-adhesion properties and the excellent biocompatibility of the PEGDA hydrogel,the hepatoma cells could form well-defined and uni-form hepatoma cell spheroids in the porous hydrogel *** found that the resistant hepatoma cell spheroids showed more significant Lenvatinib resistance and a migratory phenotype compared with a two-dimensional(2D)cell culture,which reveals the reason for the failure of most 2D cell-selected drugs for in vivo *** features give such porous hydrogel arrays promising application prospects in the investigation of tumor cell spheroid culture and in vitro drug resistance.

摘要：设计了一种含有三层衍射光学元件的60°视场头盔显示目镜,并给出了系统优化过程和结果.在整个视场和设计波段范围内三层衍射光学元件的衍射效率均在90%以上,提高了系统的光能利用率和像的对比度.此目镜光学系统的出瞳直径为8mm,出瞳距离为22mm.整个系统重量仅为8g,总长度为26.8mm,结构轻便紧凑,具有良好的光学性能,满足头盔显示目镜的使用需求.

摘要：Localization is one of the substantial issues in wireless sensor networks. The key problem for the mobile beacon localization is how to choose the appropriate beacon trajectory. However, little research has been done on it. In this paper, firstly, we deduce the number of positions for a beacon to send a packet according to the acreage of ROI (region of interest); and next we present a novel method based on virtual force to arrange the positions in arbitrary ROI; then we apply TSP (travelling salesman problem) algorithm to the positions sequence to obtain the optimal touring path, i.e. the reduced beacon trajectory. When a mobile beacon moves along the touring path, sending RF signals at every position, the sensors in ROI can work out their position with trilateration. Experimental results demonstrate that the localization method, based on the beacon reduced path, is efficient and has flexible accuracy.