科学发展当创新图强

谈创新对石油和化学工业科学发展的重要性.创新工作包括观念、管理、技术和品牌4方面.创新工程除了国家组织重大科技专项、科技配套专项外,还要对创新工程予以政策、税收、融资的支持和注意培养创新人才.     

Origin of the High Permittivity and Varistor Behavior in SnO2–Zn2SnO4 Composite Ceramics

SnO₂–Zn₂SnO₄ composite ceramics with a colossal dielectric permittivity and varistor behavior are prepared by traditional ceramic processing. By increasing bias voltage from 0 to 10 V at a low frequency (~10³ Hz) and at room temperature, the relative permittivity decreased rapidly from about 20 000 to several thousand, whereas the radius of the semicircle in the complex impedance decreased and the tail gradually disappeared. However, the peak height and the position of the imaginary part of the complex modulus in the spectra were independent of the applied DC voltage. The slope deduced from the bias voltage‐dependent straight lines of the double‐logarithmic imaginary permittivity spectra were constant with a value of ?0.63 at high frequencies and they decreased to ?1 at low frequencies. The results strongly indicate that a number of weekly trapped charges existed in the ceramic bulk. From the temperature‐dependent dielectric and electric modulus spectra, the trapped charge activation energy was about 0.32 eV, which may be associated with the oxygen vacancies. Based on the results, a modified equivalent circuit related to the colossal dielectric permittivity and varistor properties was proposed, in which a Warburg impedance was added in parallel with the resistance and capacitance.     

POI共建LTE双路室分系统建设成本分析

详细论述了POI系统实现原理、POI系统技术特点、LTE室分双路常见解决方案;结合工程实际案例,着重论述了多家运营商是如何通过POI共建室分系统实现LTE室分双路建设方案的;详细分析了POI共建节约室分建设投资情况,为LTE双路室分系统共建方案的选取提供宝贵经验。     

An amphoteric poly(VAc‐DBM‐AM‐DMAPS) emulsion focusing on the ecological sand‐fixing in salty desert: Structure and properties

In order to control the impacts of blown sand in salty desert, in this article, the amphoteric emulsion, for the first time, was applied as an ecological sand‐fixing material. This study started from the synthesis of the poly{vinyl acetate‐dibutyl maleate‐acrylamide‐co‐3‐[N‐(2‐methacroyloylethyl)‐N, N‐dimethylammonio]‐propane sulfonate} [P(VAc‐DBM‐AM‐DMAPS)] copolymer emulsion. Then, the structures, composition, thermal property of the emulsion were characterized by ¹H‐NMR, FTIR, and DSC, respectively. The basic properties of the emulsion and salt tolerance of the latex films were measured by using viscometer, dynamic light scattering, and laser Doppler electrophoresis also. And the sand‐fixing properties of the emulsion were evaluated. Finally, the influence of the emulsion on the growth of soil microbe and plants were discussed for understanding its ecological effect. The experimental results showed that the emulsion has been successfully synthesized and could be as an ecological sand‐fixing material. The related reason is that, first, the emulsion could significantly improve the compressive strength and water retaining; second, the emulsion had good thermal aging, freeze‐thaw stabilities and salt tolerance to withstand the changes in temperature and NaCl concentration of salty desert; third, the influence of the emulsion on the growth of plants and microbe of sand also showed a dependable ecological effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43715.     

热处理对双辊铸轧ZK60镁合金组织及阻尼性能的影响

采用双辊铸轧法制备了ZK60镁合金条带,采用金相显微镜(OM)和动态机械分析仪(DMA)研究了热处理后ZK60镁合金条带的组织和阻尼性能。退火处理后,组织较为均匀。T6处理后组织转变为均匀的等轴晶。在温度-阻尼谱中出现了2个温度阻尼峰,P1峰为弛豫型阻尼峰,其激活能为132 kJ/mol,P2峰为非弛豫型再结晶阻尼峰。T6处理条件下,时效时间为6 h时,呈现典型的位错型应变-阻尼图谱;在其他时效时间下,呈现2种混合位错型的应变-阻尼图谱。T6态双辊铸轧ZK60镁合金的应变-阻尼性能遵循G-L理论。     

Design and simulation of thermal residual stresses of coatings on WC-Co cemented carbide cutting tool substrate

Large thermal residual stresses in coatings during the coating deposition process may easily lead to coating delamination of coated carbide tools in machining. In order to reduce the possibility of coating delamination during the tool failure process, a theoretical method was proposed and a numerical method was constructed for the coating design of WC-Co cemented carbide cutting tools. The thermal residual stresses of multi-layered coatings were analytically modeled based on equivalent parameters of coating properties, and the stress distribution of coatings are simulated by Finite element method (FEM). The theoretically calculated results and the FEM simulated results were verified and in good agreement with the experimental test results. The effects of coating thickness, tool substrate, coating type and interlayer were investigated by the proposed geometric and FEM model. Based on the evaluations of matchability of tool substrate and tool coatings, the basic principles of tool coating design were proposed. This provides theoretical basis for the selection and design of coatings of cutting tools in high-speed machining.

     

基于FWD的半刚性基层开裂状况无损评价模型

为无损判别半刚性基层开裂状况,以落锤式弯沉仪(FWD)为平台反演基层模量,分析弯沉盆匹配法和规律法模量反演结果的差异,进行基层反演模量与开裂状况的相关性分析,以基层模量比为评价指标,建立基层开裂状况无损评价模型和评价标准。研究表明：铣刨后的半刚性基层表面可视化损坏模式主要为裂缝;与弯沉盆匹配法相比,弯沉盆规律法的模量反演结果唯一且土基模量变异性较低;基层模量比与基层开裂状况在半对数坐标下具有良好的线性关系;基层开裂状况可分为四类,基层模量比分界值分别为0.68、0.47、0.30。该评价模型适用于不同强度的半刚性基层损坏状况的无损判别,可为路面大中修设计是否翻修半刚性基层提供决策支持。     

高压喷射注浆技术在灰岩地区的应用

介绍了高压喷射注浆技术的应用历史、工作机理及其在灰岩地区的应用实例.     

Active control of hydraulic oil contamination to extend the service life of aviation hydraulic system

The hydraulic system is the control center of aircraft, the performance of which is critically dependent on the purity of the oil that flows through it. Contamination of hydraulic system oil has been known to be the primary cause of catastrophic failure and accidents. A review of literature in the area of hydraulic oil contamination reveals three facts: (i) there is a dearth of effective methods to prevent intrusion of external contaminants into the hydraulic oil, (ii) there are no effective purification methods for liquid and gaseous contaminants of oil, and (iii) there is an absence of real-time monitoring for major contaminants. This work systematically reviews the hazards, sources, and removal methods of major contaminants, especially of gaseous contaminants. An active method to control oil contamination is proposed instead of the existing passive maintenance techniques that are ridden with problems. In a case study of aviation hydraulic system, our active control system comprises (i) a closed hydraulic circuit and a closed oil tank to prevent the intrusion of external contaminants, (ii) a vacuum centrifuge to efficiently remove contaminants without creating consumption costs, and (iii) monitoring devices installed to actively monitor the contaminant content in oil during operation. The results from the purification experiments and three-dimensional modeling indicate that the active control of hydraulic oil contamination can effectively remove 98.4% solid contaminants and reduce the water content below 50 ppm, and in particular reduce the gas content below 2%. It is obvious that this method can improve the continuous operation capability of aviation hydraulic systems and extend the intermaintenance period of aircrafts by reducing the contaminant content in oil.