Synthesis and properties of new water‐soluble copolymers based on methyl acrylic acid sucrose ester and methyl acrylic acid

The new series of copolymers were obtained based on free radical solution copolymerization by mixing self‐made methyl acrylic acid sucrose ester (MASE) and methyl acrylic acid (MAA) with different ratios. Copolymerization behavior and properties of the new copolymers was investigated with the reaction time, temperature, monomer ratios and characterized by Fourier transform infrared spectra (FT‐IR), carbon nuclear magnetic resonance (¹³C NMR), and intrinsic viscosity. The results indicated that sucrose was successfully grafted onto poly (methyl acrylic acid). Further, it was demonstrated that low temperature benefited the esterification of MASE. Importantly, the copolymers were founded to have good compatibility with polymethyl methacrylate (PMMA), polytetrafluoroethylene (PTFE), and polyethylene (PE). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43627.     

Evaluation of a novel profile control agent for enhancing an oil‐recovery application

In this study, a kind of novel profile control agent, polymer/montmorillonite composite particle (PMCP), which was prepared by an in situ intercalative polymerization method involving rubbers and a hydrophobic monomer (HM), was provided with the aim to modify the injection profile for enhancing oil recovery. The chemical structure of the PMCP was characterized by Fourier transform infrared spectroscopy and X‐ray diffraction, respectively. The results prove that the intercalation effect occurred between the polymer and montmorillonite. The swelling properties of the PMCP was studied under harsh reservoir conditions as a function of the aging time to determine the effect of rubbers and HM. The toughness of the optimal particle was investigated by a maximum pressure method followed by core experiments to evaluate the injection and profile improvement performance. The data indicated that PMCP‐4 containing the rubber of nitrile butadiene rubber and HM showed advanced properties, such as the swelling ratio, heat resistance, salinity tolerance, and water retention, compared to the other PMCPs. Moreover, the PCMP also exhibited superior toughness, injectivity, and profile control ability. Therefore, PMCP‐4 is a promising profile control agent, especially in fractured formations with harsh conditions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43756.     

Polyether‐based main‐chain‐type polytriazole elastomer with benzoxazine via a 1,3‐dipolar cycloaddition reaction

A novel functional polyether‐based elastomer with a benzoxazine structure in its main chain was successfully synthesized via a 1,3‐dipolar cycloaddition reaction. Benefitting from a facile one‐pot synthesis strategy, the elastomer was prepared at low temperature (80°C) and was characterized clearly afterward. The azide‐terminated polyether and acetylene‐terminated benzoxazine were used as the soft and hard segments, respectively, in the polymer chain. Because the triazole rings served as stable linkage between the soft and hard segments, the elastomer possessed good thermal stability (the 5% weight loss temperature could exceed 350°C) compared to traditional elastomers, such as polyurethane. The rigid benzoxazine rings provided the product with good mechanical properties (the tensile strength of the elastomer could exceed 30 MPa). Furthermore, the ring‐opening polymerization of oxazine rings in the structure gifted the elastomer with possibility of thermally induced structural transformation. The thermally induced structural transformation could conveniently realize the conversion of the elastomer to a thermosetting resin. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42820.     

三旋光结构一步无进位加法器的设计

针对现阶段光学计算机研究中涉及的光学加法器硬件制备困难,输入有限定性等问题,基于MSD(Modified Signed-Digit)加法原理及对称MSD编码技术,设计并实现了一种全新的光学加法器-三旋光结构一步式无进位加法器。阐述了该加法器的主光路结构设计过程和方案,给出了三旋光器抽象结构,分析和设计了控制光路的光路结构,并给出了易于硬件制备的电路实现具体方案。该加法器制备简单,对输入没有限制,并且可以一步并行完成数以千位的加法。针对上述光路和电路实现方案进行了实验验证,完成了13位以内的二进制数的无进位加法运算。实验结果表明:本文所设计的一步式无进位加法器原理正确、方案合理,并具有众多数据位数并行运算的潜力。     

Sc,La对Al-Mg焊料中杂质元素偏聚的调控作用

采用金相显微镜、扫描电镜、能谱分析和X射线衍射仪,研究了添加微量钪、镧对铝镁焊料中杂质元素偏聚的调控作用. 结果表明,在铝镁焊料合金凝固过程中,铁、硅等杂质元素在晶界有偏聚效应,添加微量钪、镧可以降低铁、硅杂质在晶界的偏聚浓度. 钪与镧减轻杂质元素在晶界偏聚的效果存在差别,添加钪的合金比添加镧的合金晶界处杂质元素偏聚强度明显减弱. 造成这种差别的原因是,钪、镧对杂质元素偏聚的调控机制不同.     

Improving Blood Compatibility of Polyethersulfone Hollow Fiber Membranes via Blending with Sulfonated Polyether Ether Ketone

Appropriate membrane for blood contacting applications requires hemocompatibility and high permeation flux; it should inhibit proteins or platelets adsorption and still possess high permeability. Aiming to improve the polyethersulfone (PES) hollow fiber membrane hemocompatibility, sulfonated polyether ether ketone (SPEEK) is self‐synthesized in the present research and added to PES in different ratios. Scanning electron microscopy images have revealed significant changes in PES membranes structure after addition of SPEEK, which can influence water permeation property of the membranes. Water contact angles of the membranes have reduced from 75° to 50° after addition of 4 wt% SPEEK. Influence of SPEEK addition on hemocompatibility of the PES membranes is evaluated via protein (bovine serum albumin) adsorption, platelet attachment, and coagulation time (APTT and TT) assays. Obtained results reveal that hemocompatibility of the modified hollow fiber membranes is enhanced as a result of emerging repulsive forces between negative charges on the membranes surface and negatively charge blood components.

     

Effects of Nb Addition on Charpy Impact Properties of TiVTa Refractory High-Entropy Alloy

In the present study, the effects of Nb addition on Charpy impact properties of TiVTa refractory high-entropy alloy with high strength-ductility trade-off were systematically studied by using the instrumented Charpy impact testing machine. The experimental results showed that the impact toughness was remarkably improved by Nb addition in TiVTa to form TiVTaNb alloy. The crack initiation energy and propagation energy of TiVTaNb were 67.3% and 24.9% higher than that of TiVTa, indicating that Nb addition simultaneously reinforced the resistance to crack initiation and propagation. The impact fracture of TiVTaNb exhibited larger bending degree of shear lips, deeper dimples and more secondary cracks which effectively dissipated more impact energy. The deformation mechanism of TiVTa alloy was dominated by dislocation activities. While in TiVTaNb, the deformation mechanism was synergized by dislocation activities and deformation twinning, which were the main contributors for the improved impact properties and the stronger crack resistance of TiVTaNb alloy under impact loading.     

Ti-xCr-yCu钛基材料的制备及组织性能研究

研究了Al-Cu-Li-(0.35Mg)-(0.2In)合金的拉伸性能、时效析出相类型及其分布。T6峰时效时,Al-Cu-Li合金的时效析出相为T1(Al2CuLi)和?? (Al2Cu)相。添加0.2%In时,T6态时效早期形成许多方块状的立方相Al5Cu6Li2,且随时间延长其尺寸保持稳定;同时,可促进? ?相析出;相应合金的时效响应加速,强度提高。同时添加In和Mg可抑制Al5Cu6Li2相析出,但促进T1相析出。In和Mg的复合微合金化效果小于2050铝锂合金中Ag和Mg的复合微合金化效果,因而In+Mg复合微合金化铝锂合金T6态强度低于Ag+Mg复合微合金化的2050铝锂合金。T8态时效时,时效前预变形产生的位错抑制了In元素单独添加和In+Mg复合添加的微合金化效果。     

108 m3聚合釜引发剂用量及加入技术对树脂质量的影响

引发剂是调节氯乙烯悬浮聚合反应速率,并影响聚合放热、聚合周期和聚合釜生产能力的重要助剂。引发剂对氯乙烯悬浮聚合动力学的影响主要与引发剂的活性、用量有关。引发剂用量、加入方式和前后期使用比例等对树脂质量也有明显的影响。     

Synthetic Activity of Recombinant Whole Cell Biocatalysts Containing 2-Deoxy-D-ribose-5-phosphate Aldolase from Pectobacterium atrosepticum

In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications.