界面酸碱配位作用对粘合性能影响的研究

通过测定参照液在固体表面的接触角并计算接触体系的粘附功及其酸碱作用成份,研究了带碱性基团的丙烯酰胺——天然橡胶接枝聚合物和带酸性基团的丙烯酸——天然橡胶接枝聚合物表面的酸碱配位作用及其对粘合性能的贡献.     

An experimental comparison of a graphite electrode and a gas diffusion electrode for the cathodic production of hydrogen peroxide

This work studies the production of hydrogen peroxide through the cathodic reduction of oxygen in acidic medium, by comparing the results obtained using a commercial graphite and a gas diffusion electrode. A low pH was required to allow the application of hydrogen peroxide generation to an electro-Fenton process. The influence of applied potential and the gas flow composition were investigated. The gas diffusion electrode demonstrates a higher selectivity for hydrogen peroxide production, without significantly compromising the iron regeneration, thus making its successful application to a cathodic Fenton-like treatment, possible. Unlike the graphite cathode, the gas diffusion cathode also proved to be effective in the air flow.     

ZnO·Al2O3·nSiO2玻璃抗裂纹萌生能力反常演化的结构起源探索

为探究ZnO·Al₂O₃·nSiO₂玻璃抗裂纹萌生能力(C_R)随SiO₂含量变化的演化规律,制备了一系列不同n值(n=2,2.35,2.5,2.65,3,3.5)的样品。基于C_R和结构表征发现,C_R随着n的增加呈先增大后减小的反常演化,并于n=2.5时出现极值(31.1 N)。这是源于随着n增大:(1)原子堆积份数逐渐减小,可致密化体积逐渐增加,从而导致C_R逐步提高;(2)Al—O多面体结构单元含量逐步减少,导致C_R逐步下降;(3)考虑到相界面对裂纹生长的强阻挡能力,中程异构分相(富Al和富Si相)致相界面数量呈先增多后减少的变化趋势,导致C_R产生类似的非单调演化。上述三个因素的竞争和协同作用是该体系中C_R呈反常演化的结构起源,但考虑到极值点附近较小的组分变化,中程异构致相界面数量随n增加呈现的非单调演变才应是C_R呈反常演化的主要结构根源。     

High pressure EIGA preparation and 3D printing capability of Ti—6Al—4V powder

Ti—6Al—4V alloy powder was processed by electrode induction melting gas atomization (EIGA) at high gas pressure (5.5–7.0 MPa). The effects of atomizing gas pressure on the powder characteristics and the microstructure, along with the mechanical properties of the as-fabricated block by laser melting deposition (LMD), were investigated. The results indicate that the diameters of powders are distributed in a wide range of sizes from 1 to 400 μm, and the median powder size (d₅₀) decreases with increasing gas pressure. The powders with a size fraction of 100–150 μm obtained at gas pressures of 6.0 and 6.5 MPa have better flowability. The oxygen content is consistent with the change trend of gas pressure within a low range of 0.06%–0.20%. Specimens fabricated by LMD are mainly composed of α+β grains with a fine lamellar Widmanstatten structures and have the ultimate tensile strength (UTS) and yield strength of approximately 1100 and 1000 MPa, respectively. Furthermore, the atomized powders have a favorable 3D printing capability, and the mechanical properties of Ti—6Al—4V alloys manufactured by LMD typically exceed those of their cast or wrought counterparts.     

Self-sufficient Cytochrome P450s and their potential applications in biotechnology

Cytochrome P450s(CYPs) are ubiquitously found in all kingdoms of life, playing important role in various biosynthetic pathways as well as degradative pathways; accordingly find applications in a vast variety of areas from organic synthesis and drug metabolite production to modification of biomaterials and bioremediation.Significantly, CYPs catalyze chemically challenging C—H and C—C activation reactions using a reactive high-valent iron-oxo intermediate generated upon dioxygen activation at their heme center,while the other oxygen atom is reduced to the level of water by electrons provided through a reductase partner protein.Self-sufficient CYPs, encoding their heme domain and reductase protein in a single polypeptide, facilitate increased catalytic efficiency and render a less complicated system to work with.The self-sufficient CYP enzyme from CYP102A family(CYP102A1, BM3) is among the earliest and most-investigated model enzymes for mechanistic and structural studies as well as for biotechnological applications.An increasing number of self-sufficient CYPs from the same CYP102 family and from other families have also been reported in last decade.In this review, we introduce chemistry and biology of CYPs, followed by an overview of the characteristics of self-sufficient CYPs and representative reactions.Enzyme engineering efforts leading to novel self-sufficient CYP variants that can catalyze synthetically useful natural and non-natural(nature-mimicking) reactions are highlighted.Lastly, the strategy and efforts that aim to circumvent the challenges for improved thermostability, regio-and enantioselectivity,and total turnover number; associated with practical use of self-sufficient CYPs are reviewed.     

Toward a brief multidimensional assessment of emotional intelligence: Psychometric properties of the Emotional Quotient Inventory—Short Form.

Although several brief instruments are available for the emotional intelligence (EI) construct, their conceptual coverage tends to be quite limited. One notable exception is the short form of the Emotional Quotient Inventory (EQ-i:S), which measures multiple EI dimensions in addition to a global EI index. Despite the unique advantage offered by the inventory, psychometric properties of the EQ-i:S scores have not yet been systematically evaluated. Such an evaluation was the main goal of the present investigation. Using data from 2,508 undergraduates, the authors conducted 2 studies involving factor structure, internal reliability, 6-month temporal stability, and construct validity of the EQ-i:S responses, both for the total EQ scale and for each constituent dimension. The results supported the multidimensional measurement structure of the EQ-i:S, with each dimension producing internally consistent, temporally stable, and theoretically meaningful responses. Scores on the EQ-i:S were associated more strongly with performance on an ability test of EI and with a conceptually similar construct of alexithymia than with the broader dimensions of basic personality and explained nontrivial amounts of incremental variance in the criterion symptoms of attention deficit/hyperactivity disorder. Moreover, scores on each EQ-i:S dimension exhibited unique patterns of associations with the validation variables. The discussion highlights the advantages of the multidimensional approach in the assessment and study of EI. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

关于平面 n 次系统奇点指数为1的有限奇点的上界问题的讨论

通过具体例子,证明了平面n次系统奇点指数为1的有限远奇点个数的上界不小于(1/2)n(n+1)。为解决Hilbert第十六问题作了必要和基本的工作。     

TP80共享 BCM—Ⅲ的 DBASE—Ⅱ数据库

本文讨论了TP801在局域网中共享DBASEⅡ数据库的一种方法.以提高计算机资源的利用率和单板机TP801的功能,为生产过程参数的实时打印报表提供了一个实用工具。     

氯化丁基橡胶和三元乙丙橡胶共交联的研究

本工作对氯化丁基橡胶(CIIR)和三元乙丙橡胶(EPDM)并用胶的共交联问题作了初步的探讨。重点进行了并用胶硫化体系的选择,试验结果表明在 CIIR/EPDM 并用胶的树脂硫化体系中,加入适量的硫黄和促进剂 TMTD可使并用胶的交联密度提高,物理—机械性能明显改善。通过中心合成设计试验法考察了树脂、硫黄和 TMTD 对并用胶料物理性能的影响。采用差示溶剂法和交联密度法测试了并用胶的共交联程度,结果表明 CIIR/EPDM 并用,选择适当的硫化体系可以实现共交联。     

Mo—Al催化体系合成高乙烯基1,2—聚丁二烯的研究

以 MoCl_3(OOCC_7H_(15))_2-(i-Bu)_2AlO-■(Mo-Al)为催化剂,在加氢汽油中,对丁二烯(Bd)聚合活性进行了研究,考察了聚合条件对聚合活性、聚合物分子量以及微观结构的影响。结果表明,本体系催化活性较高,在酸/钼=6,Mo/Bd=2.0×10~(-4),Al/Mo=50(摩尔比),于50℃聚合5小时,丁二烯转化率达80%。最佳聚合活性条件:正辛酸/MoCl_5=3,聚合温度60℃,Al/Mo=60,(当 Mo/Bd=2.0×10~(-4)时)。Al/Mo 值适宜范围为20—90。制得的聚合物1,2—链节含量高于80%。