Numerical modelling of a low power non-transferred arc plasma reactor for methane conversion

Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane, which is the main component of shale gas, were simulated. The temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD) code and a commercial ANSYS-FLUENT code; the transport of chemical species was analyzed as including the chemical reactions of methane conversion. The simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%. Three C₂ hydrocarbon gases with ethane (C₂H₆), ethylene (C₂H₄), and acetylene (C₂H₂) were selected as the converted species of methane from experimental data. The mass fraction of C₂ hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also calculated. Those values show good agreement with the actual experimental results in that the major conversion reaction occurred in C₂H₂ and hydrogen, and the conversions to C₂H₆, C₂H₄, and hydrogen were minor reactions of methane pyrolysis conversion.     

Effect of coupling agent content on properties of composites made from polylactic acid and chrysanthemum waste

Chrysanthemum flower is among one of the highly sought after and widely planted flower crops, in particular for cultural and religious ceremonies. However, the chrysanthemum stem and stalk have little value and usually discard as by‐product waste from floristry. The objective of this research is to investigate the potential value of utilizing chrysanthemum stem and stalk as reinforcing fillers for thermoplastic composites. In this study, 2‐mm thick composite sheet containing predefined formulations of polylactic acid (PLA), chrysanthemum waste filler (CWF) ranging from 15 to 60 phr, and maleated polyethylene (MAPE) coupling agent up to 5 phr were prepared with the aid of Haake internal mixer and compression molding. The effect of MAPE loading on tensile, thermal, and morphological properties of PLA/CWF composites was investigated. The findings revealed that PLA/CWF composite attained improved tensile modulus compared to the neat PLA, and the tensile modulus increases with higher concentration of CWF. However, both tensile strength and elongation at break reduces with increase loading of CWF. Overall, PLA/CWF composites with MAPE shows better performance compared to those without MAPE, where an optimum strength of 21.8 MPa can be achieved with 60 phr CW and 3 phr MAPE. The measured tensile strength is comparable to alternatives natural fiber thermoplastic composites demonstrating its potential to be used in non‐structurally demanding application. J. VINYL ADDIT. TECHNOL., 26:10–16, 2020. © 2019 Society of Plastics Engineers     

转底炉烟气系统堵塞、腐蚀及防腐探索

烟气余热利用系统是转底炉生产工艺重要的组成部分，余热锅炉又是烟气余热利用系统的核心设备。对转底炉烟气特性进行了分析，重点介绍了某钢厂转底炉烟气余热利用系统工艺流程及工艺参数；对烟气余热利用系统堵塞、锅炉管腐蚀原因进行了分析，在实践基础上，提出了烟气余热利用系统防堵、防腐蚀的措施，并对余热锅炉防腐进行了有益探索。通过这些措施的实施，减轻了烟气余热利用系统的堵塞和腐蚀，并在转底炉实际生产中得到了验证,为解决转底炉烟气余热利用系统堵塞、腐蚀提供了有益的借鉴。     

Etching characteristics of thin SiON films using a liquefied perfluorocarbon precursor of C6F12O with a low global warming potential

Perfluorocarbon gas is widely used in the semiconductor industry. However, perfluorocarbon has a negative effect on the global environment owing to its high global warming potential (GWP) value. An alternative solution is essential. Therefore, we evaluated the possibility of replacing conventional perfluorocarbon etching gases such as CHF₃ with C₆F₁₂O, which has a low GWP and is in a liquid state at room temperature. In this study, silicon oxynitride (SiON) films were plasma-etched using inductively coupled CF₄ +C₆F₁₂O+O₂ mixed plasmas. Subsequently, the etching characteristics of the film, such as etching rate, etching profile, selectivity over Si, and photoresist, were investigated. A double Langmuir probe was used and optical emission spectroscopy was performed for plasma diagnostics. In addition, a contact angle goniometer and x-ray photoelectron spectroscope were used to confirm the change in the surface properties of the etched SiON film surface. Consequently, the etching characteristics of the C₆F₁₂O mixed plasma exhibited a lower etching rate, higher SiON/Si selectivity, lower plasma damage, and more vertical etched profiles than the conventional CHF₃ mixed plasma. In addition, the C₆F₁₂O gas can be recovered in the liquid state, thereby decreasing global warming. These results confirmed that the C₆F₁₂O precursor can sufficiently replace the conventional etching gas.     

民族地区院校中药应用型人才培养模式研究

针对少数民族地区医药院校的特点,对培养面向基层经济建设需要的中药应用型人才的培养目标及培养模式进行了探索,初步总结中药应用型人才的培养模式,从人才培养模式的定位、课程体系构建、多元化的人才评价体系的构建,突出实验技能培训,改革教学方法手段,强化科研实习等方面的改革,培养以能力为本位的应用型人才。     

以就业为导向的药学多元化实践基地的探讨

探讨以社会求与学生就业意愿有机结合为导向的药学多元化实践基地建设思想,通过建设以学生生源地为依据的广西各地市三甲医院、药检所、制药企业等实习基地,方便学生学习及就业。建立"双模块双导师制"实践模式,强化岗前思想道德教育和技能训练,培养适合社会求的新型药学应用型人才。     

世界博览会与建筑技术的发展

本文从建筑技术的角度入手，从建筑材料、结构、及相关技术等三方面，探讨了世界博览会对于建筑技术的发展所起到的展示和促进作用，初步探讨了世界博览会与建筑学发展之间的关系。     

某边坡稳定概率分析研究

岩土参数具有明显的随机性和变异性,传统安全系数评价方法把各种设计条件、各种指标和参数都定值化,并选用一定的计算模式来进行计算,得到的分析结果与实际不能完全吻合。本文采用目前相对精确的验算点法对某边进行稳定概率分析,并与安全系数作比较。     

培养学生工程索赔意识和能力的研究与实践

工程索赔是承包商保护自身正当权益、弥补工程损失、提高经济效益的重要和有效手段 ,能极大提高合同管理、项目管理和企业培养、工程索赔意识、能力、研究管理水平。文章通过理论教学、课程设计和社会实践等教学环节 ,对学生工程索赔意识和能力的培养进行了探讨     

设备尺度对可燃材料失重速率的影响

文章分别利用锥型量热计和火灾早期特性实验台对柞木的失重速度进行了实验测量。研究结果表明：尺度效应的作用非常明显。相同辐射能量条件下，相比于火灾早期特性试验台实验，锥型量热计实验中试样容易着火，而且过程中火焰稳定，火陷持续时间较长。