Organocatalytic Enantioselective Michael Reaction of Aminomaleimides with Nitroolefins Catalyzed by Takemoto’s Catalyst

Known as electrophiles, maleimides are often used as acceptors in Michael additions to produce succinimides. However, reactions with maleimides as nucleophiles for enantioselective functionalization are only rarely performed. In this paper, a series of bifunctional Takemoto’s catalysts were used to organocatalyze the enantioselective Michael reaction of aminomaleimides with nitroolefins. The resulting products were obtained in good yields (76–86%) with up to 94% enantiomer excess (ee). The catalyst type and the substrate scope were broadened using this methodology.     

基于CPCI总线DMA方式的实时高速数据交换系统

针对在重离子同步加速器运行过程中,如何解决设备控制器与上层数据处理程序之间的高速数据交换的问题,自主研发了基于Compact PCI总线板卡,板载FPGA,DSP,SDRAM等资源,并设计了DMA完整控制逻辑,传输协议解译全部由硬件完成（FPGA）。多个软硬件模块共同实现了该实时高速数据交换系统。该系统经实测,结构完整自洽,数据传输带宽符合重离子同步加速器运行要求,实现了数据传输的实时性。重点描述该系统数据通路上的诸多技术环节,包括硬件和软件的功能划分、FPGA、DSP、驱动程序、上层应用等各环节的技术细节。该实时数据交换系统系原创性设计,系统解决了控制与数据采集系统的设备控制层与上层数据处理层之间的实时数据交换问题。     

利用复合换能器测量反射的二次谐波及介质的非线性参量

计算了有限振幅声波在层状媒质中的传播和反射,研究了用二次谐波反射模式的非线性声参量测量方法,设计制作了用于反射法测量非线性声参量的复合结构超声换能器,利用该换能器及有限振幅插入取代法建立了脉冲反射式测量非线性声参量B/A的实验系统,对若干流体和生物样品进行了非线性声参量的测量,其结果与现有文献上的值吻合的很好。     

Solutions of Dirac equations on compact spin manifolds via saddle point reduction

In this note, we apply the saddle point reduction to a class of nonlinear Dirac equation with a potential on a compact spin manifold. Two results are obtained, including a multiple theorem.     

超高分子量聚乙烯凝胶／结晶膜中链缠结的Raman研究

为获得超高分子量聚乙烯的超高取向性，利用准稀溶液速冷解缠方法可使λｍ＝４００，力学性能大幅度提高，但距离链的理论强度还有一定差距，ＮＭＲ的相结合研究表明其中仍残存一定量的界面层及非晶部分。从缠经链角度来看，其分子链的解缠并不能达到完全。     

Solvothermal process for grafting maleic anhydride onto poly(ethylene 1-octene)

Solvothermal process was developed to graft maleic anhydride (MAH) onto poly(ethylene 1-octene) (POE). Fourier transform infrared spectra (FT-IR) and ¹H NMR spectra confirmed that maleic anhydride was successfully grafted onto the POE. The influences of MAH content, initiator concentration, POE concentration, reaction temperature, reaction time and solvents on the graft copolymerization were investigated through both of the grafting degree (GD) and gel content (GC). The results demonstrated that high grafting degree (up to 10.85%) could be obtained while the gel content was still low. Further studies revealed that POE-g-MAH could also be achieved in poor solvents of POE through this method.     

Highly Selective Catalytic Oxi-upcycling of Polyethylene to Aliphatic Dicarboxylic Acid under a Mild Hydrogen-Free Process

A low-temperature hydrogen-free process for upcycling polyethylene (PE) plastics into aliphatic dicarboxylic acid is developed using a heterogeneous catalyst Ru/TiO₂. The low-density PE (LDPE) conversion can reach 95 % in 24 h under a pressure of 1.5 MPa air at 160 °C with 85 % of the liquid product yield, which mainly is low molecular weight aliphatic dicarboxylic acid. Excellent performances can be also achieved for different PE feedstocks. This catalytic oxi-upcycling process paving a new way of upcycling polyethylene waste.     

Photoluminescence and electroluminescence of hexaphenylsilole are enhanced by pressurization in the solid state

Application of a hydrostatic pressure in the range of 1-650 atm boosted photoluminescence and electroluminescence of hexaphenylsilole by approximately 10 and approximately 73%, respectively, due to the suppression of intramolecular rotations and/or the increase in carrier injection, offering a helpful mechanistic insight into the intriguing phenomenon of aggregation-induced emission.     

Red fluorescent siloles with aggregation-enhanced emission characteristics

Aseries of new red fluorescent siloles consisting of a silole core and dimesitylboranyl substituent connected with a furan,thiophene,and selenophene bridges were synthesized and characterized.The optical properties,electronic structures,and electroluminescence (EL) performances were investigated.The emission wavelengths were red-shifted from the siloles with furan,to those with thiophene,and then selenophene.The thiophene,and selenophene-containing siloles,(MesB)_2DTTPS,and(MesB)_2DSTPS,showed the typical aggregation-enhanced emission (AEE) feature,while furan-containingone,(MesB)_2DFTPS,showed slight emission decrease as the aggregate formation.Theoretical calculations were carried out to explain the difference in the optical properties.Undoped OLEDs using these red siloles as light-emitting layers were fabricated.The device of (MesB)_2DTTPS exhibited the bestper formance.It radiated red ELemission at 589 nm,and afforded good maximum luminance,current,power,and external quantum efficiency of13300cdm~(-2),4.3cd A~(-1),2.9 lmW~(-1),and1.8%,respectively.