聚乙二醇在N-烃化反应中的相转移催化作用

N-烃基邻苯二甲酰亚胺类化合物是合成脂肪族伯胺和α-氨基酸的重要中间体。近年来,Landini,D.,Santaniallo,E.等先后报道过在鎓盐存在下进行邻苯二甲酰亚胺的相转移催化烃化反应。

环状季铵盐类化合物研究Ⅲ．DCAS的合成及相转移催化作用

设计并合成了新的环状季铵盐ＤＣＡＳ。选择苯酚与环氧氯丙烷，在无水碳酸钾存在下，固－液相转移催化醚化形成苯基缩水甘油醚为基本反应，比较了ＤＣＡＳ与其他几种季铵盐的相转移催化作用。结果表明，ＤＣＡＳ具有很好的相转移催化性能，与ＴＢＡＳ相当。

聚乙二醇相转移催化作用下Darzens酯缩合

环氧酸酯缩合作用通常在无水条件下进行,不能在应用氢氧化钠水溶液的相转移催化条件下进行。因为卤代酸酯在此情况下发生水解。M.Makosza在无水碳酸钾和18-冠醚-6的两相体系中合成了2-苯基环氧酸乙酯,b.p.99-109℃/0.5mmHg产率72%。

聚氧乙烯类表面活性剂在二氯卡宾制备中的相转移催化作用

聚氧乙烯类表面活性剂可作为制备二氯卡宾时的相转移催化剂,其效能与分子中氧乙烯(EO)单位的数目有关。

聚氯乙烯多乙烯多胺树脂的相转移催化作用

聚氯乙烯多乙烯多胺树脂可作为酯水解、氧取代(醚和酯的合成)、卤素取代(丁基碘和硫氰酸卞酯的合成)和缩合反应(卞叉丙酮的合成)的催化剂,效果良好。它是一种新型的高分子相转移催化剂。

硫酸铵在孔雀石的黄药直接浮选中的相转移催化机理研究

以铵盐－孔雀石浮选体系的溶液化学研究为基础，通过测试分析和计算，探讨和论证了无机铵盐在孔雀石浮选中的相转移催化理论。

相转移催化技术在无机化工中的拓展

相转移催化理论一直应用于有机物的合成领域。相转移催化技术也可用于无机盐水溶液或固态盐类与有机物之间的液—液和固—液多相反应。将相转移催化技术理论首次拓展到无机难溶盐之间的固—固类型转化反应中 ,利用此技术 ,可从生产硼砂的废渣硼泥中提取出轻质碳酸镁 ,为硼泥的综合利用提供了一条经济。

β-(β′-氯乙氧基)苯乙醚的三相相转移催化合成

利用固载化聚乙二醇和固载化季铵盐作三相相转移催化剂 ,以苯酚和β,β′-二氯二乙醚为原料合成了β- (β′-氯乙氧基 )苯乙醚 .该合成方法具有收率高、反应条件温和等优点 .催化反应结束后 ,所用固载催化剂易于回收 。

洗衣粉催化氧化甲苯合成苯甲酸及其创新教育

使用廉价的市售洗衣粉为相转移催化剂,用高锰酸钾氧化甲苯合成苯甲酸,操作简单易行,反应时间大大缩短,回流反应15min在80～90℃条件下,产率为52%。新的合成方法本身是实验教学中进行创新教育的结晶,同时也可利用洗衣粉的相转移作用进行STS教育。

(苯乙烯-丁二烯-氧乙烯)多嵌段共聚物的某些特性

本文研究了(苯乙烯-丁二烯-氧乙烯)多嵌段共聚物的相转移催化能力和与LiClO_4形成络合物的导电性能以及在高分子共混时的增容作用。结果表明,该共聚物对Williamson固-液相反应具有良好的相转移催化作用;在氯醇橡胶与ABS共混中可作为增容剂,添加3％左右,即可显著地改善共混物的力学性能;与LiClO_4形成的络合物在35℃的导电率可达4×10^(-4)S·cm^(-1)。

季铵盐在取代反应中的应用

讨论了季铵盐在有机取代反应中的相转移催化作用。阐明了应用季铵盐时的反应条件。

Effect of Energy Transfer on UV Spectra of “H-shaped” Azobenzene Derivatives

A series of “H-shaped” organic dimers （azobenzene derivatives） exhibit linear absorption red shift compared with their corresponding monomers experimentally. Dipolar interaction model is not appropriate for the azobenzene derivatives due to the small distance between two “D-π-A” chains. Energy transfer model is suggested for explanation of the absorption red shift. Two necessary conditions for energy transfer were verified. In addition, bi-exponential florescence-delay behavior of the dimer as well as Bella＇s quantum chemistry calculation shows evidence of energy transfer.

A Minireview of Marine Algal Virus-Coccolithoviruses

Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce ＇the coccoliths＇. It is considered to be the second most productive calcifying organism on earth and becoming an important factor in the global carbonate cycle. Emiliania huxleyi is one of the only two bloom-forming coccolithophores and becomes a species crucial to the study of global biogeochemical cycles and climate modeling. Coccolithoviruse is a recently discovered group of viruses infecting the marine coceolithophorid E. huxleyi. They are a major cause of coceolithophore bloom termination, and DMSP concentration is increasing in the process of viral lysis. Phylogenetic evidences support that some genes are functional both in E. huxleyi and its virus （EhV）. Horizontal gene transfer （HGT） of multiple functionally coupled enzymes occurs in E. huxleyi and its DNA virus EhV has been confirmed, which contributes to the diversification and adaptation of plankton in the oceans and also critically regulates virus-host infection by allowing viruses to control host metabolic pathways for their repli- cation. Therefore, it is of particular interest to understand this host-virus interaction. On this issue, we have made a minireview of coeeolithoviruses focusing on the basic characteristics, phylogenesis, horizontal gene transfer and the interaction between the host and its viruses, as well as its important role in global biogeochemical cycling.

Implementation of Controlled Geometric Phase Gate for Two Trapped Neutral Atoms

We propose a scheme for realizing a controlled geometric phase gate for two neutral atoms.We apply thestimulated Raman adiabatic passage to transfer atoms from their ground states into Rydberg excited states, and use theRydberg interaction induced energy shifts to generate geometric phase and construct quantum gates.

Ultrafast Electron Transfer in All-Small-Molecule Photovoltaic Blends Promoted by Intermolecular Interactions in Cyanided Donors

Cyano substitution has been established as a viable approach to optimize the performance of all-small-molecule organic solar cells.However,the effect of cyano substitution on the dynamics of photo-charge generation remains largely unexplored.Here,we report an ultrafast spectroscopic study showing that electron transfer is markedly promoted by enhanced intermolecular charge-transfer interaction in all-small-molecule blends with cyanided donors.The delocalized excitations,arising from intermolecular interaction in the moiety of cyano-substituted donor,undergo ultrafast electron transfer with a lifetime of∼3 ps in the blend.In contrast,some locally excited states,surviving in the film of donor without cyano substitution,are not actively involved in the charge separation.These findings well explain the performance improvement of devices with cyanided donors,suggesting that manipulating intermolecular interaction is an efficient strategy for device optimization.

Modeling of Ions Mobility in Plasma Like Concept and Transfer Processes in Electrolyte Solutions

Plasma like concept of ions in electrolyte solutions is accepted as a basis for development of equation mobility for transfer processes （viscosity, diffusion, thermal conductivity and electrical conductivity）. The examples of isomorphism of dissipative processes are given in the article. The integrated assessment equation of transfer properties is developed based on the ion-dipole, dipole-dipole and ion-ion interactions and the force of liquid dielectric resistance to oscillating solvated particles. It is shown that the estimated magnitude of viscosity, diffusion, electrical conductivity and thermal conductivity are comparable with the current knowledge and experimental values in a wide range of electrolyte concentrations.

Iron porphyrin with appended guanidyl group for significantly improved electrocatalytic carbon dioxide reduction activity and selectivity in aqueous solutions

Iron porphyrins have high activity and selectivity for electrocatalytic CO_(2)reduction reaction(CO_(2)RR)in nonaqueous solutions,but they usually display poor or moderate selectivity for CO_(2)RR in aqueous solutions because of the competitive hydrogen evolution reaction.Using water as the electrocatalytic reaction solvent is more favored because not only it is cheap,green and abundant but also it can sufficiently provide protons required for CO_(2)RR.Therefore,developing Fe porphyrins as electrocatalysts for efficient and selective CO_(2)RR in aqueous solutions is of both fundamental and practical significance.Herein,we report the design and synthesis of Fe porphyrin 1 with an appended guanidyl group and its electrocatalytic features for CO_(2)RR in both nonaqueous and aqueous solutions.In acetonitrile,Fe porphyrin 1 and its guanidyl-free analogue,tetrakis(3,4,5-trimethoxyphenyl)porphyrin 2,are both efficient for electrocatalytic CO_(2)-to-CO conversion,but the turnover frequency with 1(3.9´10^(5)s^(-1))is one order of magnitude larger than that with 2(1.7´10^(4)s^(-1)),showing the critical role of the appended guanidyl group in improving electrocatalytic CO_(2)RR activity.More importantly,in 0.1 mol L^(-1)KHCO_(3)aqueous solutions,1 showed very high selectivity for electrocatalytic CO_(2)-to-CO conversion with a Faradaic efficiency of 96%,while 2 displayed a Faradaic efficiency of 65%for the CO_(2)-to-CO conversion.This work is of significance to show the effect of appended guanidyl group on improving both activity and selectivity of Fe porphyrins for CO_(2)RR electrocatalysis.

Liver angiogenesis: tumor host interaction in non-metastatic colorectal cancer

Objective: Angiogenesis is a crucial step for tumor growth and progression. Changes of liver angiogenesis (without metastatic invasion) in response to primary tumors are not known. The aim of the study was to investigate the liver angiogenesis in non-metastatic colorectal cancer (CRC). Methods: Human colorectal adenocarcinoma tumors were grown subcutaneously in nude mice. All animals showed tumor growth locally without macroscopic or microscopic evidence of liver metastases. Livers were investigated for their microvessel density (MVD) at different stages of tumor growth (as small, medium, and large-sized tumors). Normal non-tumor-bearing mice served as controls. To assess MVD, two endothelial cell markers (anti-CD34 and -CD31 antibodies), image analysis, and immunofluorescent technique were utilized. Enumeration of positive stained endothelial cells revealed the MVD. Results: Non-metastatic livers showed increased levels of MVD vs. control. Moreover, levels of MVD were higher in small and medium-sized tumor groups versus large sized tumor groups. Conclusion: The present data indicate that angiogenesis in the liver is induced in early-stages of CRC. However, this effect is suppressed with advanced tumor growth. These results provide an additional rationale for including antiangiogenic therapy in the treatment of early stages of CRC.

Higher-Order Interactions： Understanding the knowledge capacity of social groups using simplicial sets

A predominant benefit of social living is the ability to share knowledge that cannot be gained through the information an individual accumulates based on its personal experience alone. Traditional computational models have portrayed sharing knowledge through interactions among members of social groups via dyadic networks. Such models aim at understanding the percolation of information among individuals and groups to identify potential limitations to successful knowledge transfer. How- ever, because many real-world interactions are not solely pairwise, i.e., several group members may obtain information from one another simultaneously, it is necessary to understand more than dyadic communication and learning processes to capture their full complexity. We detail a modeling framework based on the simplicial set, a concept from algebraic topology, which allows elegant encapsulation of multi-agent interactions. Such a model system allows us to analyze how individual information within groups accumulates as the group＇s collective set of knowledge, which may be different than the simple union of individually contained information. Furthermore, the simplicial modeling approach we propose allows us to investigate how information accumulates via sub-group interactions, offering insight into complex aspects of multi-way communication systems. The fundamental change in modeling strategy we offer here allows us to move from portraying knowledge as a ＂token＂, passed from signaler to receiver, to portraying knowledge as a set of accumulating building blocks from which novel ideas can emerge. We provide an explanation of relevant mathematical concepts in a way that promotes accessibility to a general audience [Current Zoology 61 （1）： 114--127, 2015].

Experimental and numerical investigations on convective heat transfer of dual piezoelectric fans

An investigation is performed to study the convective heat transfer performance under dual piezoelectric fans. Three main aspects are involved in the current study. Firstly, vibration tests for dual specific piezoelectric fans actuating at the first-mode resonant frequency are conducted to illustrate the influence roles of vibrating phase difference and fan-to-fan pitch on the piezoelectric fan vibration amplitude. Secondly, heat transfer measurements are made to compare the heat transfer among single fan, dual fans in-phase and dual fans out-of-phase. Thirdly, three-dimensional numerical simulations are conducted to reveal the influence mechanism of dual piezoelectric fans on heat transfer. The results show that, the vibrating phase difference of dual fans has nearly no influence on the displacement velocity and amplitude of piezoelectric fan related to single fan once the dimensionless pitch(P/W) is beyond 1.2. The dual piezoelectric fans produce nearly the same peak heat transfer coefficient as that of single fan case.Of particular is that the dual fans operating in-phase produce more favorable heat transfer than the dual fans operating out-of-phase,especially in the gap zone between dual fans. Due to the interaction between dual fans, the streaming flow induced by one vibrating fan suffers the action of sweeping flow of another vibrating fan when they operate out-of-phase. While for the dual fans operating in-phase, the streaming flows induced by vibrating fans merge together to form stronger wall jet flow in the region between two fans.