一种新型的室温快速固化胶黏剂的研制

本文开发了一种新型的方舱夹芯板用室温固化高强度环氧结构胶黏剂,验证了其物化特性、相关力学性能和环境适应性。结果表明此胶黏剂具有优良性能,可以满足方舱用大板胶黏剂的使用需求。     

转锈稳锈材料在石油钻采设备薄壁件表面的应用

石油钻采设备中存在部分薄壁板件(厚度不超过3 mm),在喷砂或喷丸过程中极易造成变形,故实际生产中只能手工打磨清理。但是手工打磨效率较低,且一旦手工清理不彻底,会影响产品的防腐质量。为提升石油钻采设备中薄壁防腐质量,引进了新材料——转锈稳锈材料。通过控制变量,使用拉拔仪检测不同变量下涂层附着力;对转锈稳锈材料和传统的手工处理进行比较,考察其对不同品牌的油漆是否具有兼容性。研究结果表明:转锈稳锈材料与传统的手工打磨清理相比在增加漆膜附着力方面更具有优势,而且与大多数的油漆具有兼容性。     

Behaviour of 54.4SiO2-13.7Na2O-1.7K2O-5.0CaO-12.4MgO-0.6Y2O3-11.3Al2O3-0.9B2O3 HT-SOFC glass sealant under oxidising and reducing atmospheres

The behaviour of the promising glass sealant 54.4SiO₂-13.7Na₂O-1.7K₂O-5.0CaO-12.4MgO-0.6Y₂O₃-11.3Al₂O₃-0.9B₂O₃ for solid oxide fuel cells (SOFCs) under SOFC operating conditions was studied. First, the kinetics of the crystallisation processes at the operating temperature (850 °C) was discussed (maximum exposure time of 1000 h), and the effect of crystallisation on the coefficient of thermal expansion (CTE) of the sealant was studied. Furthermore, the degradation processes at the interface of the glass sealant and functional SOFC materials (Crofer 22 APU, YSZ, and NiO(Ni)-YSZ) during exposure to 850 °C in oxidising and reducing atmospheres for 500 h were studied. The tests demonstrated good performance of the sealant studied and possibility of its application in SOFCs.     

Expert evaluation of traffic signs: conventional vs. alternative designs

Traffic sign comprehension is significantly affected by their compliance with ergonomics design principles. Despite the UN Convention, designs vary among countries. The goal of this study was to establish theoretical and methodological bases for evaluating the design of conventional and alternative signs. Thirty-one conventional signs and 1–3 alternatives for each conventional sign were evaluated for their compliance with three ergonomics guidelines for sign design: physical and conceptual compatibility, familiarity and standardisation. Twenty-seven human factors and ergonomics experts from 10 countries evaluated the signs relative to their compliance with the guidelines. Analysis of variance across alternatives revealed that for 19 of the 31 signs, an alternative design received a significantly higher rating in its ergonomics design than the conventional sign with the same meaning. We also found a very high correlation between the experts’ ratings and comprehension from previous studies. In conclusion, many countries use signs for which better alternative designs exist, and therefore UN Convention signs should be re-examined, and ergonomics experts evaluation can serve as a good surrogate for road users’ comprehension surveys.

Practitioner summary: This study presents theoretical and methodological bases for evaluating the design of UN Conventional and alternative traffic signs. Human factors and ergonomics experts evaluated 31 conventional and 68 alternative road signs, based on ergonomics principles for sign design. Results indicated the need to re-examine poorly designed UN Convention signs.     

煤矿安全监控系统的发展简述

煤矿安全监控系统是煤矿日常安全管理和灾害防治不可或缺的安全装备,然而现有安全监控系统普遍存在网络结构可靠性差、抗干扰能力弱、数字化程度低、兼容性差、智能化水平低等问题。结合监控系统升级改造的具体要求,对我国煤矿安全监测监控系统的现状,包括存在的主要问题进行了论述,并对系统升级改造后的变化及未来的发展趋势进行了探讨。分析表明,基于工业太环网、数字总线双重冗余结构的新一代全数字式煤矿安全监控系统集多主通讯、智能传感、电磁兼容等多项关键技术于一体,满足监控系统数字化、智能化以及网络化的升级改造要求,也是未来监控系统的发展趋势。新系统的应用可有效提高煤矿的防灾抗灾能力,为煤矿的安全生产提供保障。     

The role of political connection on overinvestment of Chinese energy firms

This paper explores the role of political connection on the overinvestment of Chinese energy firms. We argue that political connection can act as a “helping hand” that enables energy firms to obtain more government support to invest and a “grabbing hand” that forces politically connected energy firms to heavily overinvest for the promotion benefit of local politicians. Our analysis shows that overinvestment of an energy firm is positively affected by its political connection. In terms of the “helping hand” effects, we find that politically connected energy firms are more likely overinvest when they receive more government subsidy. In terms of the “grabbing hand” effects, we show that local politician is more likely to force energy firms to overinvest if the politician is approaching the 65-year-old promotion line. Although firms are less likely to overinvest during the economic downturn, local politician shapes the investment decision of energy firms through the “grabbing hand” effects.     

Control-faced dynamics with deformation compatibility for a 5-DOF active over-constrained spatial parallel manipulator 6PUS–UPU

Taking into account the effect of structural compliance, inverse dynamics of the active over-constrained parallel manipulator 6PUS–UPU with five degrees of freedom is solved in this article. Firstly, the relationship between driving forces and actuated force screws of each limb is derived. Then the coordination of elastic deformation between limbs which consider the effect of gravity and inertia is acquired. Finally the unique solution of driving forces for the active over-constrained parallel manipulator is derived by incorporating the force equilibrium equation of the moving platform. To validate the theoretical derivation, dynamics simulation model of manipulator based on rigid–flexible mixed structure is shown and numerical examples are given. Comparison with the traditional method of dynamics based on pseudo-inverse is also made. Finally, a feasible experimental method, as an effective test to the theoretical calculation, is proposed and applied on the prototype.     

Research on the relationship between cephalosporin structure,solution clarity,and rubber closure compatibility using volatile components profile of butyl rubber closures

Objective: Establish an effective experimental strategy to determine the compatibility of rubber closures for drugs.

Significance: Various types of rubber closures with different compositions are available for drug packaging. Many additives of rubber closures can be released from rubber closures and may affect the quality of drugs and pose a risk to human health. In this study, we aimed to determine the relationship between cephalosporin structure, solution clarity, and rubber closure compatibility using volatile components profile of butyl rubber closures.

Methods: Two opposite polarity gas chromatography (GC) systems and GC-mass spectrometry (MS) were used to achieve rapid qualitative determination of the main volatile components in rubber closures. Simulated adsorption experiment was performed to investigate the adsorption of main volatile components in rubber closures by cephalosporins with different side chain structures, and to determine the effects of adsorption on solution clarity.

Results: A volatile components screening library of rubber closures was established and the structures of some volatile component were confirmed. The specific adsorption of the structure of cephalosporins on volatile components from rubber closures was studied.

Conclusion: Based on the results of this study, rubber closures with good compatibility for cephalosporins with different side chain structures can be selected rapidly. This experimental strategy not only facilitates the screening of suitable rubber closures more effectively, but also enables the quick determination of volatile components adsorbed by drugs.     

低分子量聚丙烯酸钾的合成及其应用

采用水溶液聚合法制备了低分子量聚丙烯酸钾（PAAK），并作为新型消焰剂加入单基发射药中。通过火焰原子吸收光谱法测试了PAAK中钾的含量；用乌氏黏度计测定了特性黏度；采用DSC法研究不同pH值的PAAK与硝化棉（NC）的相容性；利用充氮氧弹法对添加PAAK、硝酸钾KNO₃、硫酸钾K₂SO₄的单基发射药的燃烧残渣进行了对比研究。结果表明，合成的PAAK中，钾的质量分数为15.21%，相对分子量在3 000左右，有利于和NC均匀混合，且在中性或微碱性（pH＝7.0~7.5）的情况与NC相容性良好。与传统的KNO₃、K₂SO₄消焰剂相比，PAAK能够和NC均匀混合，制备均质透明的单基发射药；PAAK发射药的燃烧残渣最少，占发射药质量的0.18%。     

海绵城市建设PPP项目委托代理契约分析

针对海绵城市PPP(Public-Private Partnership)项目建设、运营管理问题,为了降低由于项目参与的各方掌握信息、地位的不对称而产生的道德风险、维护各参与方的合法权益,基于一定的前提假设,构建海绵城市建设PPP项目契约模型,利用优化理论分别从代理企业和政府方两个主体的效用对模型的各个参数相关关系进行了分析,并利用数值模拟讨论了监控机制各参数对政府方监控意愿的影响。最后,结合常德市海绵城市PPP项目建设的案例,分别分析在当前考核机制下项目在建设、运营期可能存在的问题,并提出了相应的对策以解决这些问题。结果表明:代理企业的监控和激励措施具有互补性,海绵工程项目风险来源广泛,企业为规避风险会偏好零风险的固定收益,设定监控机制能激励企业更加努力的工作。