不同孔形下豆类透筛效果对比及圆筒筛优化

以大豆为对象,推导了筛孔透筛区域的面积计算公式,对比了不同孔型圆筒筛的大豆透筛效果,得出大豆在正方形筛孔的圆筒筛中透筛效果最好,并通过仿真计算对其进行了验证。在此基础上对正方形筛孔的圆筒筛进行优化,用筛分比和除杂比计算筛分效果,通过正交仿真试验分析得到不同工艺参数对圆筒筛的豆类筛分效果的影响次序,并得出最佳工艺参数为圆筒倾角5°、圆筒转速16r/min、进料速度14t/h、筛孔边长9mm,该条件下筛分效果为0.935,比原始模型提高了3.89%。     

铸态Ti-20Zr-20Al钛合金动态压缩力学性能与断裂机制研究

采用X射线衍射仪、金相显微镜、分离式霍普金森杆和扫描电镜等手段研究了Ti-20Zr-20Al钛合金在动态压缩条件下的微观结构、力学性能和断裂机制。结果表明,Ti-20Zr-20Al铸态合金由Zr基体相和TiAl/Ti₃Al针状相组成; 随着应变率增加,合金的抗压强度增加,失效应变显著增加; Ti-20Zr-20Al合金的断裂机制为解理断裂; 随着应变率增加,试验压缩断裂后碎片总数增大,平均粒径减小。采用DID模型模拟的材料碎片尺度与实验结果比较吻合,Grady模型与实验结果的偏差较大。     

无源光网络标准发展及关键技术研究

无源光网络(Passive Optical Network,PON)作为当今接入网的主要技术解决方案,具有带宽使用效率高、传输距离远、抗干扰能力强等特点.通过研究PON技术的发展动态,本文首先归纳了各种PON技术的产生背景和应用特点,整理出各技术间的连接关系及主要标准;其次介绍了PON技术的帧结构,并对带宽、波长、传输模式等PON技术的主要参数进行了汇总;然后将国内外研究热点进行划分,围绕媒体访问控制协议、帧结构、动态带宽分配算法、节能机制等关键技术,阐述了其研究现状及在PON中的重要作用;最后对PON技术的发展趋势进行了展望.     

A distributed energy system integrating SOFC-MGT with mid-and-low temperature solar thermochemical hydrogen fuel production

Solar thermochemical hydrogen production with energy level upgraded from solar thermal to chemical energy shows great potential. By integrating mid-and-low temperature solar thermochemistry and solid oxide fuel cells, in this paper, a new distributed energy system combining power, cooling, and heating is proposed and analyzed from thermodynamic, energy and exergy viewpoints. Different from the high temperature solar thermochemistry (above 1073.15 K), the mid-and-low temperature solar thermochemistry utilizes concentrated solar thermal (473.15–573.15 K) to drive methanol decomposition reaction, reducing irreversible heat collection loss. The produced hydrogen-rich fuel is converted into power through solid oxide fuel cells and micro gas turbines successively, realizing the cascaded utilization of fuel and solar energy. Numerical simulation is conducted to investigate the system thermodynamic performances under design and off-design conditions. Promising results reveal that solar-to-hydrogen and net solar-to-electricity efficiencies reach 66.26% and 40.93%, respectively. With the solar thermochemical conversion and hydrogen-rich fuel cascade utilization, the system exergy and overall energy efficiencies reach 59.76% and 80.74%, respectively. This research may provide a pathway for efficient hydrogen-rich fuel production and power generation.     

基于壳聚糖多孔碳的制备及电容性能研究

以壳聚糖为碳源和氮源,采用预碳化处理和KOH活化两步法制备了壳聚糖多孔碳材料,考察了活化剂KOH用量对电极材料形貌、结构以及电容性能的影响。结果表明:当KOH与预碳化壳聚糖质量比为0.6∶1时,制备的多孔碳材料KOH-CTS-0.6具有最优的电化学性能。KOH-CTS-0.6具有大比表面积(1 348 m~2·g~(-1)),含有丰富的N、O元素(2.9%N和7.4%O)。在电流密度为0.5 A·g~(-1)时,KOH-CTS-0.6的比电容为235.2 F·g~(-1),显示出优秀的倍率能力;在电流密度为10 A·g~(-1)的大电流时,其比电容依然高达178.6 F·g~(-1)。此外,该材料还具有良好的循环稳定性,500次循环后比电容保持率为94%。     

秸秆微晶纤维素用作片剂崩解剂的初步评价

对实验室自制秸秆微晶纤维素用作片剂崩解剂进行了初步评价。参照《中国药典》(2010版)中微晶纤维素的有关规定,评估自制秸秆微晶纤维素的质量;以阿司匹林为模型药物,以市售微晶纤维素(PH-101)为对照,测定秸秆微晶纤维素的溶胀性、崩解性。结果表明,自制的秸秆微晶纤维素质量符合《中国药典》有关规定,且溶胀性和崩解性优于市售微晶纤维素(PH-101),可用作片剂崩解剂。在秸秆微晶纤维素含量为20%时,崩解速度最快。     

基于Q-learning的不确定环境BDI Agent最优策略规划研究

BDI模型能够很好地解决在特定环境下的Agent的推理和决策问题,但在动态和不确定环境下缺少决策和学习的能力。强化学习解决了Agent在未知环境下的决策问题,却缺少BDI模型中的规则描述和逻辑推理。针对BDI在未知和动态环境下的策略规划问题,提出基于强化学习Q-learning算法来实现BDI Agent学习和规划的方法,并针对BDI的实现模型ASL的决策机制做出了改进,最后在ASL的仿真平台Jason上建立了迷宫的仿真,仿真实验表明,在加入Q-learning学习机制后的新的ASL系统中,Agent在不确定环境下依然可以完成任务。     

Preparation and polymerization of isopimaric acid derivatives

Isopimaric acid is a typical rosin compound and can account for 30% of the total mass of slash pine rosin. The molecular structure of isopimaric acid derivatives features an unsaturated double bond at the C13 position, opening up the possibility of their industrial polymerization. In this study, isopimaric acid (95.4%), methyl isopimarate (99.5%), and allyl isopimarate (95.1%) were prepared as highly pure monomers. New experimental results are presented and mechanisms based on the investigation of free-radical polymerization under UV irradiation are proposed. New rosin monomers for potential value-added utilization of woody biomass are also identified. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47817.     

卡尔费休法测定液态氯乙烯中水含量的研究

采用卡尔费休法测定了液态氯乙烯单体中的水含量。试验确定了采样工具、样品的预处理方式及选用溶剂的最优方案,并进行了精密度与准确度的验证。结果表明卡尔费休法测定液态氯乙烯单体中的水含量准确、快速,可以用来准确、及时地指导生产。