超高压技术处理对白酒物理特性和风味的影响

采用超高压技术在不同条件下对新酿白酒进行了处理,研究了压力对白酒电导率、氧化还原电位、总酸含量、表面张力及风味的影响,分析了超高压催陈白酒的效果。结果表明:超高压处理可使新酿白酒的电导率、氧化还原电位、总酸含量、表面张力趋向于陈酒。较低的压力处理对酒的风味有明显改善,过高的压力会破坏酒的风味。在20℃200MPa下处理2h,酒的风味最好。当处理压力高于400MPa时,酒会失去原有的风味。     

温度-浓度耦合变量下甲烷吸收谱线关联分析

采用可调谐激光吸收光谱技术对甲烷体积分数进行检测时,由于测量环境温度变化导致气体吸收谱线线强发生变化,将对测量结果造成不可避免的影响。基于直接吸收光谱法分析不同甲烷体积分数(1.0%～15.0%)在温度290～350 K时吸收谱线特性变化规律,采用多项式回归和共享参数全局线性拟合得到温度-甲烷体积分数耦合变量甲烷光谱吸光度关联式。结果表明:相同温度下,甲烷光谱吸光度A随甲烷体积分数升高而增大;相同甲烷体积分数下,由于总配分函数比值r_Q在甲烷吸收光谱线强随温度变化过程中占据主导作用,r_Q随温度增大的线性降低使得甲烷线强随温度升高而减小;在甲烷体积分数1.0%～15.0%、测量温度290～350 K时,温度-甲烷体积分数耦合变量甲烷光谱吸光度关联式的反演结果相对误差小于1.000%。     

掘进巷道上覆含水层探放水施工设计

山西焦煤霍州煤电集团干河煤矿2092巷掘进期间受上覆k8砂岩含水层影响,巷道顶板出现淋水现象,不但降低了巷道掘进效率,而且软化了顶板岩体,降低了顶板支护质量,甚至会引发顶板水害事故。为了2092巷掘进安全,避免水害事故发生,决定对2092巷采取合理有效的探放水设计及安全技术措施。分析了2092巷掘进期间的上覆含水层探放水施工设计,并总结了采取的安全技术措施。从实际应用效果来看,采取探放水施工后2092巷掘进期间共计探放上覆含水层积水量达2447 m³,取得了显著应用成效。     

应用虚拟机技术的电能表的测试方法及其系统研究

使用虚拟机技术可以实现电能表软件业务应用真正的跨硬件平台,不论使用何种架构的内核等,均可使用统一的应用程序,为了保证电能表的稳定运行,需要提出相应的测试方法。研究基于虚拟机平台的电能表测试方法,可以用于基于虚拟机的电能表(简称虚拟机电能表)的测试。根据虚拟机电能表的特点,将测试分为三部分：虚拟机电能表平台测试、虚拟机电能表应用测试、虚拟机电能表功能测试,根据各个部分的差异,提出不同的测试用例,开发客户端软件并对样机进行测试。测试方法的提出保障了虚拟机电能表使用的稳定、安全、可靠。     

铸造速度对Co-Cr-W丝材连铸过程的影响

采用SolidWorks软件建模与Fluent流体模拟软件相结合,模拟了不同铸造速度下水平连铸硬脆合金Co-Cr-W丝材在结晶器内的温度分布、速度分布状况,并分析了铸造速度对凝固壁厚度和内部质元速度的影响。试制了合金圆坯丝材,并对模拟结果进行了验证分析。结果表明,当铸造速度为1.5m/min时,合金液既能形成有效的壁厚,又不存在蓄能现象,较为适宜。模拟分析结果与实际结果相符合。     

常规物理性能测试设备在PdIr合金丝材中的应用

拉力试验机、电阻率测量装置和扫描电子显微镜是表征合金材料性能的常规测试设备。简要介绍了这些设备的测试原理以及在Pd-18Ir合金丝材中的应用。     

提高厚壁容器15CrMo(H)锻钢力学性能的研究

对15CrMo(H)钢临界点、CCT转变曲线、热处理制度、截面与力学性能进行了系统性研究。试验表明,15CrMo(H)钢合适的淬火温度为910～940℃,强度、韧性、显微组织与冷却速度有很强的对应关系。     

Backfire control and power enhancement of a hydrogen internal combustion engine

Frequent backfire can occur in inlet port fuel injection hydrogen internal combustion engines (HICEs) when the equivalence fuel–air ratio is larger than 0.56, thus limiting further enhancement of engine power. Thus, to control backfire, an inlet port fuel injection HICE test system and a computational fluid dynamics model are established to explore the factors that cause backfire under high loads. The temperature and the concentration of the gas mixture near the intake valves are among the essential factors that result in backfire. Optimizing the timing and pressure of hydrogen injection reduces the concentration distribution of the intake mixture and the temperature of the high-concentration mixture through the inlet valve, thus allowing control of backfire. Controlling backfire enables a HICE to work normally at high equivalence fuel–air ratio (even beyond 1.0). A HICE with optimized hydrogen injection timing and pressure demonstrates significant enhancement of the power output.     

Thermal oxidation‐induced long chain branching and its effect on phase separation kinetics of a polyethylene blend

Thermal oxidation‐induced long chain branching (LCB) during the molding processes for polyolefin copolymer poly(ethylene‐co‐butene) (PEB) and its blend with another polyolefin copolymer poly(ethylene‐co‐hexene) (PEH/PEB 50/50 blend, denoted as H50) was investigated mainly by rheological measurements. LCB with different levels could be introduced on PEB backbones by changing the molding temperature and/or molding time, which could be sensitively characterized by changes of rheological parameters, that is, storage modulus G′ and complex viscosity η*. Thermal oxidation‐induced LCB of PEB in H50 samples could largely influence the phase separation kinetics. Rheological measurements and phase‐contrast optical microscope observations coherently indicated that thermal oxidation‐induced LCB of PEB more or less retarded the development of phase separation and once it reached a certain level, the reduced chain diffusion even arrested phase separation. The decrease of mass‐averaged molecular mass in H50 with high LCB level was ascribed to the reduced hydrodynamic volume. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A theoretical study of possible shape and phase changes of carbon nanotube crystals during contraction and expansion

We present a theoretical study of the phase transformations of crystals composed of single wall carbon nanotubes self-assembled by the intertube van der Waals interaction under contraction and expansion, and report a new hexagonal crystal structure caused by expansion of the crystal. We show that when the diameter of the nanotubes is larger than certain critical value, the nanotubes in the crystals will undergo three phase transformations: the closely-packed hexagonal phase I → assembled circular phase → new hexagonal phase II → isolated circular phase. These transformations are proved by both a hybrid atomic-continuum approach and the density functional theory calculations.