Time for China to Diversify Crude Sources

With tensions rising between Western countries and Iran and geo-political risks increasing,it’s time for China to further diversify its crude oil import sources. The European Union(EU)has reached an agreement to impose sanctions against Iranian oil exports,a move that drove Brent crude oil prices higher. Sanctions against Iran would inevitably affect China, which would probably reduce its reliance on that nation due to political     

基于FPGA+DSP的数字化LCR设计与实现

以矢量化伏安法为研究背景,设计出一种基于软件无线电思想的高集成度、通用性强的数字化阻抗测量系统。该测量系统采用现场可编程门阵列FPGA及高速浮点数字处理芯片DSP为主要处理器,通过EMIF外部总线拓展接口及强大数据处理能力,结合时钟、电源、DAC数模转换和ADC模数转换模块,形成了并行与浮点计算优势互补的数字信号处理系统,解决了数字化矢量伏安法基带信号的并行处理及复杂的浮点模型解算问题,该系统能具有体积小、精度高等特点,经过实际试验测试,该系统性能稳定,具有广泛的运用前景。     

Analysis of one-dimensional consolidation of soft soils with non-Darcian flow caused by non-Newtonian liquid

Based on non-Darcian flow caused by non-Newtonian liquid, the theory of one-dimensional (1D) consolidation was modified to consider variation in the total vertical stress with depth and time. The finite difference method (FDM) was adopted to obtain numerical solutions for excess pore water pressure and average degree of consolidation. When non-Darcian flow is degenerated into Darcian flow, a comparison between numerical solutions and analytical solutions was made to verify reliability of finite difference solutions. Finally, taking into account the ramp time-dependent loading, consolidation behaviors with non-Darcian flow under various parameters were analyzed. Thus, a comprehensive analysis of 1D consolidation combined with non-Darcian flow caused by non-Newtonian liquid was conducted in this paper.     

Formation and Height of the Interconnected Fractures Zone after Extraction of Thick Coal Seams with Weak Overburden in Western China

Formation of a zone of interconnected fractures during coal mining is a key factor in mine flooding. Coal mines in western China are characterized by thick coal seams with mechanically weak overburden. In situ studies including drill core analysis, drilling fluid loss measurement, and borehole video monitoring were used at the working face 101 in Shaanxi Jinjitan coal mine to explore the maximum height of the interconnected fractures zone (IFZ). Also, tests on a scaled physical model and numerical simulation based on the drilling data were used to study the formation of the fractured zone. By considering data from other mines with similar mining conditions, a logarithmic relationship was found between the maximum height of the IFZ and the thickness of coal excavation. The maximum height of the IFZ was found to be 27 times the thickness of the excavated coal seam, which is far more than in coal mining areas in eastern China. Also, the IFZ in overlying strata of the study area was arch-shaped, not saddle-shaped, as had been observed in previous studies.     

Berberine as an Environmental-Friendly Inhibitor for Hot-Dip Coated Steels in Diluted Hydrochloric Acid

The inhibition effect of an excellent environmental-friendly corrosion inhibitor-berberine on hot-dip coated steels in the diluted HCl has been investigated by using quantum chemistry analysis, mass-loss tests, electrochemical measurements and scanning electron microscopy (SEM) observation. Calculation results show that berberine has a nearly planar structure with a number of active centers. The value of Mulliken charge, and the distribution of the highest occupied molecular orbital (HOMO) and the lower unoccupied molecular orbital (LUMO) imply that berberine has a good ability of electron exchange with metal surface. The test results indicate that inhibition efficiency (IE%) increases with the inhibitor concentration and the highest IE can reach 99%. Adsorption of berberine on the coating surface follows Langmuir adsorption isotherm with a single molecular layer by chemisorption.     

致密WC增强铁基表面复合材料的原位制备与形成机理

利用铸渗复合-热处理工艺制备致密碳化钨增强铁基表面复合材料,研究了不同保温时间下复合材料的物相组成与微观组织.结果表明,不同保温时间下,复合材料表面均有致密碳化钨层生成,反应层厚度最大为148 μm.致密碳化钨层的显微硬度随保温时间无明显变化,均明显高于铁基体.铁基表面致密碳化钨的形成主要依赖于Fe-C-W体系中碳和钨原子的扩散与原位反应.     

Fatigue strength and microstructure evaluation of Al 7050 alloy wires recycled by spray forming,extrusion and rotary swaging

Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7xxx alloys. The 7050 alloy machining chips were spray formed, hot extruded, rotary swaged and heat-treated in order to improve mechanical properties. Microstructures, tensile properties and fatigue strength results for a 2.7 mm-diameter recycled wire are presented. Secondary phases and precipitates were investigated by XRD, SEM, EBSD, TEM and DSC. As-swaged and heat-treated (solution and aging) conditions were evaluated. Mechanical properties of both conditions outperformed AA7050 aerospace specification. Substantial grain refinement resulted from the extensive plastic deformation imposed by rotary swaging. Refined micrometric and sub-micrometric Al grains, as well as coarse and fine intermetallic precipitates were observed. Subsequent solution treatment resulted in a homogeneous, recrystallized and equiaxed microstructure with grain size of 9 μm. Nanoscale GP(I) zones and η′ phase precipitates formed after aging at 120 °C, imparting higher tensile (586 MPa) and fatigue (198 MPa) strengths.     

仓泵技术应用于电石粉尘回收装置的探讨

根据陕西金泰氯碱化工有限公司新建的电石粉尘回收装置的运行情况,探讨了仓泵技术的应用及仓泵在运行过程中的异常情况。指出装置运行后降低了电石消耗,每年可产生约400万元的经济效益,同时也降低了企业的安全风险,改善了乙炔生产现场环境。     

维生素E对猪肉肌内脂肪和肌纤维直径影响的Meta-分析

目的:探讨维生素E(VE)添加对猪肉肌内脂肪和肌纤维直径的影响。方法:检索ScienceDirect、Google学术搜索、Web of Science、中国知网、万方数据库1990年1月~2013年6月发表的观察VE添加对猪肉肌内脂肪和肌纤维直径影响的随机对照研究,Meta分析计算合并标准均数差(SMD)及95%置信区间(CI)。结果:最终12篇文献纳入本次研究,观察VE添加后肌内脂肪的文献为10篇,观察VE添加后肌纤维直径的文献为7篇,和对照组比较,VE添加与肌内脂肪的SMD为0.77(-0.04,1.58)(p=0.06),差异不显著,与肌纤维直径的SMD为-1.05(-1.84,-0.26)(p<0.05),差异具有统计学意义。结论:VE添加组较对照组提高肌内脂肪所占比例影响不显著,但能显著减小肌纤维直径,改善猪肉品质。     

F3000曲轴箱裂纹形成原因及其解决措施

介绍了F3000曲轴箱的浇注方式及造型、制芯和熔炼工艺,检测了曲轴箱圆角处的残余应力分布情况,分析了曲轴箱裂纹的形成原因,提出了改变芯砂清理方式、控制开箱时间和增大铸件开裂位置的过渡圆角和壁厚,以消除铸件应力,减少或避免裂纹.经生产验证,加工后的F3000曲轴箱圆角处未见裂纹,取得了显著的效果.