基于参数预标定的长行程PMLSM无传感器控制

为了解决长行程定子不连续永磁直线同步电机存在的因无法全程安装位置传感器和不同动子和定子之间的电磁参数不固定所造成的控制性能下降的难题,提出一种在每一段定子内先进行参数标定,再进行速度控制的控制系统设计。首先,在动子进入过程中,对电机进行电磁参数标定,根据标定参数对控制器参数进行调整,以达到更好的控制效果。然后,使用无位置传感器控制系统使动子快速达到设定速度值并稳定运行。实验结果表明:动子进入过程参数标定精度分别为0.002Wb和0.000 4H;无位置传感器控制中位置估计精度为0.63mm,速度收敛时间为0.45s,稳态误差为0.02m/s。基本满足永磁直线同步电机用于长行程运输的控制快速性、稳定性等要求。     

Inhibition of Soluble Epoxide Hydrolase Ameliorates Phenotype and Cognitive Abilities in a Murine Model of Niemann Pick Type C Disease

Niemann–Pick type C (NPC) disease is a rare autosomal recessive inherited childhood neurodegenerative disease characterized by the accumulation of cholesterol and glycosphingolipids, involving the autophagy-lysosome system. Inhibition of soluble epoxide hydrolase (sEH), an enzyme that metabolizes epoxy fatty acids (EpFAs) to 12-diols, exerts beneficial effects in modulating inflammation and autophagy, critical features of the NPC disease. This study aims to evaluate the effects of UB-EV-52, an sEH inhibitor (sEHi), in an NPC mouse model (Npc) by administering it for 4 weeks (5 mg/kg/day). Behavioral and cognitive tests (open-field test (OF)), elevated plus maze (EPM), novel object recognition test (NORT) and object location test (OLT) demonstrated that the treatment produced an improvement in short- and long-term memory as well as in spatial memory. Furthermore, UB-EV-52 treatment increased body weight and lifespan by 25% and reduced gene expression of the inflammatory markers (i.e., Il-1β and Mcp1) and enhanced oxidative stress (OS) markers (iNOS and Hmox1) in the treated Npc mice group. As for autophagic markers, surprisingly, we found significantly reduced levels of LC3B-II/LC3B-I ratio and significantly reduced brain protein levels of lysosomal-associated membrane protein-1 (LAMP-1) in treated Npc mice group compared to untreated ones in hippocampal tissue. Lipid profile analysis showed a significant reduction of lipid storage in the liver and some slight changes in homogenated brain tissue in the treated NPC mice compared to the untreated groups. Therefore, our results suggest that pharmacological inhibition of sEH ameliorates most of the characteristic features of NPC mice, demonstrating that sEH can be considered a potential therapeutic target for this disease.     

汽车密封件双料一体旋转模具设计

针对PP+TPE汽车密封件设计了大型双料一体旋转注射模,介绍了二次合模的精确定位、可控注射系统、顶出平衡设计。该模具技术能够使两种性能完全不同的材料按照指定区域分布,并且达到塑件尺寸的精度需求,实现同时与钣金、玻璃、塑件等不同材质的零件进行复合配套。本项目实施后,在模具精度、寿命等方面接近或部分达到国外同类产品先进水平,而价格仅为国外产品的40%,性价比优势明显。     

"不知火"柑橘全自动包装生产线的设计与研究

目的为了解决柑橘在实际包装过程中因于人工手动装袋、装箱等导致的效率低下问题,设计一条全自动柑橘包装生产线。方法基于“不知火”柑橘的特殊体型特征,使用传送带分级装置对其进行分级;通过倾斜皮带解决柑橘排列姿态的整理问题;经给袋式包装机装袋后,采用扭结式扎口装置对其进行封口;利用并联机器人对其进行装箱。通过计算生产节拍,合理规划每个工序的循环时间,并通过Flexsim软件对该生产线进行仿真分析与平衡优化。结果该生产线整体效率由89%提升到93%,能够正常运行且满足生产力的需求。结论该柑橘包装生产线实现了柑橘的分级、整料、装袋、装箱等工序,降低了工作强度,提高了生产效率,实现了包装过程的自动化。     

Expanding the Toolbox of R-Selective Amine Transaminases by Identification and Characterization of New Members

Amine transaminases (ATAs) are used to synthesize enantiomerically pure amines, which are building blocks for pharmaceuticals and agrochemicals. R-selective ATAs belong to the fold type IV PLP-dependent enzymes, and different sequence-, structure- and substrate scope-based features have been identified in the past decade. However, our knowledge is still restricted due to the limited number of characterized (R)-ATAs, with additional bias towards fungal origin. We aimed to expand the toolbox of (R)-ATAs and contribute to the understanding of this enzyme subfamily. We identified and characterized four new (R)-ATAs. The ATA from Exophiala sideris contains a motif characteristic for d -ATAs, which was previously believed to be a disqualifying factor for (R)-ATA activity. The crystal structure of the ATA from Shinella is the first from a Gram-negative bacterium. The ATAs from Pseudonocardia acaciae and Tetrasphaera japonica are the first characterized (R)-ATAs with a shortened/missing N-terminal helix. The active-site charges vary significantly between the new and known ATAs, correlating with their diverging substrate scope.     

Modification of exposure conditions by the magnetic field configuration in helicon antenna-excited helium plasma

Modification of exposure conditions downstream in the diffusion chamber has been performed in helicon antenna-excited helium plasma by adjusting the magnetic field(intensity and geometry).In the inductively coupled mode(H mode), a reduction in ion and heat fluxes is found with increasing magnetic field intensity, which is further explained by the more highly magnetized ions off-axis around the last magnetic field lines(LMFL). However, in helicon wave mode(W mode), the increase in magnetic field intensity can dramatically increase the ion and heat fluxes.Moreover, the effect of LMFL geometry on exposure conditions is investigated. In H mode with contracting LMFL, off-axis peaks of both plasma density and electron temperature profiles shift radially inwards, bringing about a beam with better radial uniformity and higher ion and heat fluxes. In W mode, although higher ion and heat fluxes can be achieved with suppressed plasma cross-field diffusion under converging LMFL, the poor radial uniformity and a small beam diameter will limit the size of samples suitable for plasma irradiation experiments.     

基于软件校准的短波发射机功率控制系统设计

短波发射机功率稳定一直是通信领域致力改善的重点问题,短波发射机功率不稳定会直接影响无线电通信质量,造成通信失真、表达不清晰等问题。针对上述问题,基于软件校准设计短波发射机功率控制系统。该系统借鉴MVC设计模式搭建系统数据库层、业务逻辑层、控制层以及界面显示层基础框架；将功率计与短波发射机相连,实时采集工作状态下的短波发射机功率数据,通过信号处理器实施处理后并存储,借鉴传输元件,将数据发送到控制器,通过控制器校准短波发射机功率与预期之间的偏差,以偏差量为输入,利用改进PID运算得出控制量,生成控制命令,通过输入输出信号接口板输出命令,控制驱动装置调节短波发射机运行参数,实现功率控制。结果表明：与 控制系统、自动调谐系统应用相比较,在所设计系统应用控制下,100s内短波发射机的功率变化曲线与预期曲线之间的拟合优度指数更大,更接近1,优于对比系统,说明相比于对比系统。本系统控制表现更好,更能维持短波发射机功率稳定,达到了研究目标。     

平行流式电机周向水套结构参数对散热性能影响研究

针对电力机车上某功率密度为1.27 kW/kg的平行流式电机周向水套结构的散热问题进行了研究。首先利用热阻网络法建立了平行流多通道截面的热阻数学模型;然后借助FLUENT软件对水套的电机散热过程进行了数值模拟,并对结构参数进行了优化;最后通过实验验证了计算的正确性。结果表明:当通道孔数n增大时,总热阻普遍减小;当通道单孔宽度x增大时,总热阻先增大后减小,当n=6个、x=1.670 mm时,水套具有最佳的散热性能;水套各测温点的数值模拟温度与实验测量温度之间的相对误差均低于5.00%。     

超声波解冻与传统解冻方式的比较与竞争力评估

超声波解冻通过空化效应、机械效应和热效应对冷冻食品进行解冻,解冻效率高、对冷冻食品的损伤较小。该文简要介绍了空气解冻、水解冻和电解冻的解冻机制及研究进展,详细阐述了超声波解冻的机制及研究进展。将超声波解冻与空气解冻、水解冻和电解冻进行对比,发现超声波解冻的解冻效率最优,且将超声波与这3种传统解冻方式结合可以提高解冻效率,并且获得更好的解冻效果。超声波频率和强度以及冻结食品的解冻温度是影响解冻效果的主要参数。超声波在食品中的衰减程度受到解冻温度的影响极大,因此在调节超声波频率和强度同时调控解冻温度对解冻效果至关重要。     

对于厚度70mm〜140mm焊缝超声检测的讨论

超声检测作为一种面积型缺陷的有效检测方法,被广泛应用在气化炉、除氧器、汽包等的焊缝检测上。随着近年来电厂、化工厂对质量的要求提升,确保焊缝质量就成了生产制造厂的重点。对于这些重型容器,焊缝厚度普遍在70mm~140mm,在这个厚度区间,采取的多道焊接,工艺控制不严很容易产生缺陷。无损检测标准的制定只是简单的对此厚度划分两个区间,并未给出划定此区间的依据。本文通过实际检测气化炉、除氧器、汽包等焊缝来讨论超声检测在厚度70mm?140mm区间的划定依据。