Theoretical Analysis and Experiment on Flow Allocation Characteristics of Dual Discharging Axial Piston Pump

通过改变缸体结构、柱塞数、端盖油路、配流盘形状等,设计了双排油内外环并联配流结构的轴向柱塞泵,实现了单柱塞泵两路高压供油。针对单环柱塞数减少,腔; 内压力冲击增大,脉动变大等问题,对配流结构进行重新设计。在排油腰形槽和吸油腰形槽过渡区取消卸荷槽,利用加大配错角,在排油完毕未接通吸油时,腔内封; 闭体积增大,未排尽的高压油液压力降低;在吸油腰形槽和排油腰形槽过渡区,排油卸荷槽利用阶梯变化通流面积代替原连续变化的通流面积,削弱了卸荷槽几何形; 状要求。重新设计后的双排油配流结构,以45mL轴向柱塞泵结构为参考,对配流结构进行了理论分析,建立了双排油轴向柱塞泵仿真模型。以单柱塞腔内压力; 冲击、输出流量进行分析研究,得外环压力冲击小,与传统配流结构相比较双排油输出口压力脉动变化率变小,并试制双排油轴向柱塞泵。对试制泵进行压力脉动测; 试、容积效率测试和噪声测试,结果表明,与45mL轴向柱塞泵进行对比,压力脉动降低了约30%,噪声也降低,容积效率不低于0.92。该双排油轴向柱; 塞泵可以代替双联泵,使系统结构简化,能耗降低。When providing two-way independent high-pressure high-flow oil sources,; hydraulic system generally adopts two separate piston pumps or coaxial; ones in series, causing complex structure and high cost. Therefore,; single piston pump was proposed to achieve two-way high-pressure oil; supply. Axial piston pump was designed with dual discharging inter-outer; ring parallel allocation structure by changing cylinder structure,; piston number, cap circuit and valve plate shape. Flow allocation; structure was redesigned due to decreased single ring piston number,; increased pressure shock and fluctuation in the chamber. Relief notch; was cancelled in transition region from oil-discharging to oil-absorbing; waist slots. After that, mismatch angle was increased to enlarge closed; volume in chamber and reduce the pressure of unexhausted high-pressure; oil in the interval between oil extraction and absorption. In transition; region from oil-absorbing to oil-discharging waist slots, stepped flow; area was used to replace original continuous flow area to weaken; geometry requirements of relief notch. The optimized dual discharging; flow allocation structure was conducted with theoretical analysis to; establish dual discharging axial piston pump simulation model based on; 45mL axial piston pump structure. There was small pressure shock in; outer race by analyzing pressure shock and output flow in single piston; chamber. Compared with traditional flow allocation structure, dual; discharging oil output had smaller pressure fluctuation rate. Based on; this, the designed dual discharging axial piston pump was piloted. The; pilot dual discharging oil pump was compared with the original 45mL; pump through pressure fluctuation, volumetric efficiency and noise; tests. Result showed that the former had lower pressure fluctuation; (decreased by 30%) and noise level, while its volumetric efficiency was; not smaller than 92%. In general, the dual discharging axial piston pump; can replace duplex pump to simplify system structure and reduce energy; consumption. This new pump can also be used in closed circuit and; differential cylinder hydraulic systems to make the system simpler and; cost-effective.山西省自然科学基金项目; 国家自然科学基金项

三维链网模型及其参数标定

提出一种材料模型，由三维空间取向的平行弹簧束作为构架，讨论了按空间取向进行离散的方式。实现立体角划分的最优化。构造了由一维构元组成的三维链网体胞，给出了体胞几何，物理参数的标定方法。证明该体胞能精确模拟Pisson比从0-1／2的材料行为，突破了已往模型0-1/3限制。探讨了模型简化问题，实现了模拟精度高而计算费用低的统一，举例论述了该模型模拟短纤维增强复合材料的独特优点

浆细胞样树突状细胞在宿主抵御隐球菌肺部感染中的作用及机制研究进展

肺隐球菌病是由隐球菌感染引起的常见真菌病,由于症状的非特异性,临床上诊断较为困难。作为条件致病性真菌感染,肺隐球菌病的结局主要与宿主免疫力有关。目前肺隐球菌病免疫学发病机制研究主要局限在T细胞和巨噬细胞。近年研究表明,作为树突状细胞亚群之一的浆细胞样树突细胞,由于其激活后可以产生大量的I型干扰素并活化相关的T细胞,所以在机体抵抗病毒和细菌免疫中发挥着重要的作用。但是浆细胞样树突细胞在真菌病,尤其是在隐球菌病的发生发展中发挥的作用尚不明确。本文将介绍肺隐球菌病的临床表现、诊治及T细胞和巨噬细胞在肺隐球菌病中的免疫机制,并通过介绍肺隐球菌病和浆细胞样树突细胞及二者之间已有报道的联系,初步阐述浆细胞样树突细胞在肺隐球菌病免疫学发病机制中的相关作用。国家自然科学基金(31770161);;上海市科学技术委员会基金(14DZ2272900);;国家卫生部基金(2018ZX10101003);;上海市科委技术标准专项(16DZ0500401)~

基于FBG传感技术的复合材料加筋板低速冲击损伤监测

针对碳纤维增强树脂基复合材料低速冲击损伤的实时监测,本文设计将布拉格光纤光栅(FBG)传感器埋植在复合材料加筋板结构的三角填充区,在线监测复合材料T型加筋板冲击损伤过程。分别将FBG传感器埋植于复合材料层合板内部和复合材料T型加筋板的三角填充区,对比FBG传感器的埋入对复合材料层合板与复合材料T型加筋板对力学性能的影响,结果表明内埋FBG传感器的复合材料层合板试样的拉伸强度比未埋植传感器的层合板试样降低了约5%,但在FBG传感器的破坏应变范围内,FBG传感器可以准确、实时地监测复合材料的应变信号。将FBG传感器埋入复合材料T型加筋板的三角填充区,内埋FBG传感器的加筋板样件压缩破坏载荷与未埋植的样件基本一致。通过对比加筋板蒙皮上冲击位置、冲击能量对FBG传感器测得的冲击过程持续时间和最大应变值的影响,表明冲击过程持续时间随着冲击能量增加而延长,最大应变值随着冲击距离的增加呈下降趋势,而最大应变值随着冲击能量的增加呈上升趋势。利用FBG传感器测得的应变信号可初步实现对复合材料T型加筋板蒙皮冲击损伤位置及冲击能量的实时监测。国家重点研发计划(2016YFD0700603);;航空科学基金(2016ZF68011);;江苏省重点研发计划(BE2015007);;福建省科技创新平台建设计划(2014H2006

Study on transformation system of alfalfa and constructed AtPCS1 plant expression vector

通过对6种不同基因型苜蓿愈伤组织的形成能力、愈伤组织的分化能力的比较发现,不同苜蓿品种间的分化率存在显著差异(P<0.05),其中甘农1号分化率最高(42.9%);对甘农1号叶片、下胚轴及子叶等外植体的分化再生能力研究发现,叶片起源的愈伤组织分化时间短,且丛生芽形成数量高于下胚轴和子叶;再生芽可在B5培养基上成苗,并在蔗糖浓度为10 g/L的1/2 MS培养基上顺利生根.据此认为,苜蓿甘农1号叶片是适于做遗传转化的理想材料.利用RT-PCR方法扩增拟南芥螯合肽合成酶(AtPCS1)基因全序列构建了AtPCS1的植物表达载体pBI121-AtPCS1,为下一步AtPCS1基因转化苜蓿奠定了基础.Six cultivars of alfalfa with different genotypes were compared with each other in their callus induction capacity and plant regeneration ability.The significant differences were observed(P<0.05) in regeneration ability of these genotypes,and the cultivar Medicago sativa'Gannong No.1' has that the highest regeneration ability.Then the callus induction and plant regeneration ability of different explants as leaf,hypocotyls and cotyledon of Gannong No.1 were studied,and found that the calluses coming from leaf differentiated much earlier and had more regeneration buds than others.The in vitro regenerated plants were successfully rooted in 1/2 MS medium and 10 g/L sugar.The results above suggested that the leaves of the cultivar 'Gannong No.1' would be fit for the ideal explants in transgenic researches.Meantime,the full length of AtPCS1 gene was amplified by RT-PCR from Arabidopsis thaliana(ecotype Columbia).Furthermore,the plant expression vector pBI121-AtPCS1 was constructed,and that were as basic for transgenic alfalfa research in future.福建省自然科学基金(D041004);; 甘肃省自然科学基金(3ZS042-B25-011);; 兰州理工大学博士基金(SB08200602)

图书馆员网络社区信息交流行为实证研究——“大旗底下”QQ群个案分析

以"大旗底下"QQ群为个案,通过对聊天记录文本和在线问卷调查的定量分析,展现了图书馆员在网络社区中的信息交流行为特征规律,并探讨了网络社区信息交流对图书馆员精神世界的影响。论文认为,可以充分利用Web2.0技术所带来的信息交流的便利和迅捷,让更多的图书馆员融入到各种专业社区中,在跨地域、跨部门的信息交流中分享专业工作经验和成功的喜悦,在信息交流中不断汲取图书馆职业精神的养分,从而有效培育起对图书馆现代理念和核心价值观的社会认同,以此推动图书馆事业的健康发展

当代中国知识分子的图书馆认同变迁研究——基于《读书》杂志(1979-2009)的文本分析

以书为媒,知识分子与图书馆有着深厚的不解之缘。通过对《读书》杂志30年来所刊载的与图书馆相关的1047篇文章进行分析,发现"阅读情结"一直是维系知识分子图书馆认同的核心因素。随着时代发展和社会思潮变迁,在不同的发展阶段,当代中国知识分子图书馆认同的内涵也随之发生变化:从"思想自由的认同",到"以人为本的认同",再到"民主保障的认同"。在与社会互动推进图书馆事业发展的进程中,展示出当代中国知识分子群体勇于解放思想、兼济天下、敢为人先的时代精神

酚酞聚芳醚酮-双马来酰亚胺体系流变行为时间-温度依赖性

采用流变仪对酚酞聚芳醚酮(PEKC)-双马来酰亚胺(BMI)树脂体系的流变特性的时间和温度依赖性进行了研究,发现:BMI树脂凝胶点对频率有依赖性,而tanδ对频率无依赖性;PEKC-BMI复合树脂体系的黏度增大主要是由于BMI对PEKC的溶解与BMI的热固化。相比较110℃和130℃两种条件,在较高温度时复合树脂体系的黏度增大主要是热固化的影响;随注胶温度提高,复合体系的凝胶时间随PEKC含量的增加而快速缩短,在较高注胶温度下凝胶模量增大较慢,在较低注胶温度下凝胶时模量随PEKC含量的增加而提高较快;随着复合树脂体系中PEKC含量的增加,该体系的凝胶活化能由4.9kJ/mol增大到65.9kJ/mol,表明该体系的凝胶化作用对温度的敏感性增大

Research Progress of Metal Material Liquid Forming Technology

随着汽车工业的迅速发展以及市场竞争对铸件质量要求的提高,推动了金属材料液态成型技术发展。从20世纪70年代压铸技术的广泛运用,到90年代挤压铸造技术的不断完善,随后挤压压铸技术不断创新,使液态成型技术向多学科渗透融合发展,应用领域不断拓展,铸件用量逐年上升。重点介绍了压铸、挤压铸造、挤压压铸这三种重要的成型技术发展以及取得的最新成果。With the rapid development of auto industry and the market competition on the increase of the requirement of the casting quality,the development of metal material liquid forming technology was promoted.From the extensive use of the die casting technology in the nineteen seventies to constant maturity of the 90's the squeeze casting technology,and then the continuous innovation of squeezing die casting,the liquid forming technology for multidisciplinary permeated and developed,application area continued to expand,and casting quantities increased year by year.The development and the latest achievements of three kinds of important forming technologies(die casting,squeezing casting and squeezing die casting) were mainly introduced.贵州省(贵阳市)工业攻关项目(黔科合GY字[2012]3004;筑科合同[2012101]2-13号

A New Mathematics Model of the Temperature Programmed Analysis Technology

以表面作用包括表面吸/脱附以及表面反应本征速率方程为基础,提出新的程序升温分析技术(TPAT)的数学模型。与经典的理论模型相比,这种新的TPAT理论模型更接近实际的程序升温分析实验过程。设计和进行特定催化剂的TPd、TPr及TPO实验,得到相应的程序升温谱图,采用新的TPAT理论模型模拟上述谱图,计算出相应的表面作用活化能等重要热力学参数。结果表明,新的理论模型具有良好的模拟性能,平均相对误差(Ard)小于1%。Based on the surface effect including surface adsorption/desorption and intrinsic kinetics rate equation,a new mathematical model of the temperature programmed analysis technology was proposed.This model is different from the classical TPAT theory models,which indicates much more coincidence with the actual reactions than other models.TPAT(TPD,TPR and TPO) experiments were designed and carried out to receive their profiles.Based on these profiles of TPAT and the simulated experiments,the novel theory model was designed and the thermodynamics parameters(such as activation energy,etc.) were deduced and calculated by this model.The results show that this model has excellent simulation with the actual experiments,and the average relative errors are easily controlled less than 1%