基于微控制器的汽车空调步进电机控制系统设计与实现

随着汽车空调的应用越来越普及,步进电机控制系统在通风阀中的控制技术至关重要,针对步进电机低频振荡、输出力矩不高、定位精度低等缺点,基于微控制器采用细分控制驱动来改善这些缺点。在详细论述了细分驱动设计原理的基础上,设计了步进电机的控制电路框图及模块内部设计原理图,实现了步进电机整步运行、4细分和32细分三种状态。测量了步进电机相电压、相电流实验波形,分析了电机运行效果,结果表明,细分驱动能够提高步进电机控制精度、输出力矩及改善低频振荡问题。     

单片机控制的步进电机脉宽调制式细分驱动系统

在对步进电机细分驱动原理进行深入研究的基础上，提出了一种新的步进电机细分驱动电路─—单片机控制的脉宽调制式细分驱动电路，并对步进电机的恒力矩均匀细分控制进行了论述。     

步进电机细分驱动系统设计

在对国内外发展现状进行研究和对当前步进电机常见控制精度问题进行分析的基础上,对步进电机的细分驱动系统进行设计,最后对其进行实验测试,实验结果表明,该步进电机细分驱动系统设计可提高步进电机控制精度。     

步进电机细分驱动技术Simulink仿真

步进电机常作为缝纫设备等的进给轴驱动电机,其运行状况影响着整个系统的性能,论文详细分析了步进电机细分驱动技术的原理,搭建了基于matlab/simulink的细分控制仿真模型,仿真结果表明对步进电机采用细分控制策略可以极大的提升电机的各种性能。     

步进电机高细分可调控制系统

利用MSP430混合处理器与步进电机专用驱动芯片DRV8812,结合"电流矢量恒幅均匀旋转"细分方法,设计一种混合式步进电机步进角64-1024细分数可调的控制系统。该系统可以通过接收上位机指令实时调节电机细分数、每秒脉冲数、转向,实现步进电机高速低细分、低速高细分运行,最小步进角可达0.1’。     

基于MC68HC908的步进电机驱动器设计

文章以Motorola微控制器MC68HC908GP32为核心,在分析混合式步进电机斩波恒流细分驱动原理的基础上,结合步进电机驱动芯片L297/298,设计出步进电机的斩波恒流细分驱动器.此细分驱动器较好降低了步进电机运行中发热现象,提高了定位准确度.     

基于FPGA的步进电机SPWM细分驱动系统的设计

系统采用FPGA设计了步进电机正弦脉宽调制细分驱动电路,提高了步进电机的步进分辨率,并设计了功率驱动电路,对细分电路输出信号进行了隔离和功率放大,以确保电机能够稳定可靠地运行。经过对二相混合式步进电机测试表明,步进电机运行平稳,定位精度较高,改善了步进电机的运行性能,适用于要求较高的实时控制系统。     

PWM细分恒流步进电机驱动电路的设计

通过合理选择步进电机细分电流波形和驱动芯片,提出并介绍了单片机控制的细分恒流步进电机驱动方案及实现技术。实验结果表明,系统的低、高频性能和起动性能有了明显的提高。     

基于FPGA的红外雷达寻源跟随小车

文章的设计是以FPGA的逻辑控制模块为系统核心。在对步进电机的细分驱动控制进行研究的基础上,将步进电机细分驱动应用于新的场合——红外源的搜索定位。该设计的FPGA模块中,包含了时钟预处理子模块、步进电机细分驱动子模块和信号处理子模块;该模块能够实现对雷达的转速控制,也能够分析信号接收时的外部红外源角度状态信息。在外围电路的设计上,配置了步进电机的驱动模块、红外信号接收模块和直流电机的驱动模块。整个系统能够很好地完成对红外源的搜寻和跟随。     

步进电视PWM恒转矩细分驱动技术研究

从一个新颖的角度,分析了步进电机细分驱动原理,并重点讨论了步进电机的电流PWM驱动技术和恒转矩驱动技术及其应用实例。     

Immunohistochemical distribution of enkephalin, substance P, and somatostatin in the brainstem of the leopard frog, Rana pipiens

The brainstems of frogs contain many of the neurochemicals that are found in mammals. However, the clustering of nuclei near the ventricles makes it difficult to distinguish individual cell groups. We addressed this problem by combining immunohistochemistry with tract tracing and an analysis of cell morphology to localize neuropeptides within the brainstem of Rana pipiens. We injected a retrograde tracer, Fluoro-Gold, into the spinal cord, and, in the same frog, processed adjacent sections for immunohistochemical location of antibodies to the neuropeptides enkephalin (ENK), substance P (SP), and somatostatin (SOM). SOM+ cells were more widespread than cells containing immunoreactivity (ir) to the other substances. Most reticular nuclei in frog brainstem contained ir to at least one of these chemicals. Cells with SOM ir were found in nucleus (n.) reticularis pontis oralis, n. reticularis magnocellularis, n. reticularis paragigantocellularis, n. reticularis dorsalis, the optic tectum, n. interpeduncularis, and n. solitarius. ENK-containing cell bodies were found in n. reticularis pontis oralis, n. reticularis dorsalis, the nucleus of the solitary tract, and the tectum. The midbrain contained most of the SP+ cells. Six nonreticular nuclei (griseum centrale rhombencephali, n. isthmi, n. profundus mesencephali, n. interpeduncularis, torus semicircularis laminaris, and the tectum) contained ir to one or more of the substances but did not project to the spinal cord. The descending tract of V, and the rubrospinal, reticulospinal, and solitary tracts contained all three peptides as did the n. profundus mesencephali, n. isthmi, and specific tectal layers. Because the distribution of neurochemicals within the frog brainstem is similar to that of amniotes, our results emphasize the large amount of conservation of structure, biochemistry, and possibly function that has occurred in the brainstem, and especially in the phylogenetically old reticular formation.     

A system for wear prediction in lubricated sliding contacts

A system of analysis is developed to predict the rate of wear in sliding contacts. The essence of the approach is the proposal that the rate of wear can be predicted only in probabilistic terms. Therefore, the estimation of the probability of wear, which can be regarded as synonymous with the probability of surface asperity contacts, precedes the calculation of the wear rate. Further, recognising the fact that wear takes place within the actual area of contact, it is argued that this area consists of plastic and elastic contacts between asperities which, in turn, have different shear strengths and contribute differently to the wear process. In the case of lubricated contact, a frictional film defect represents the influence of a lubricant on the wear process. Moreover, as in this type of contact the load is supported by both lubricating film and contacting asperities, a special procedure is provided to estimate the load supported by the asperities, because it is only that part of the load which contributes to the wear. The catastrophic form of wear in lubricated contacts, that is termed ‘scuffing’, is also considered, and the probability of scuffing, under a given set of operating conditions, is estimated. The predictive system has been tested and its predictions are compared with available experimental results.     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

Reliability prediction of the fatigue life of a crankshaft

Crankshaft, the core element of the engine of a vehicle, transforms the translational motion generated by combustion to rotational motion. Its failure will cause serious damage to the engine so its reliability verification must be performed. In this study, the S-N data of the bending fatigue limit of a crankshaft are derived. To evaluate the reliability of the crankshaft, reliability verification and analysis are performed. For the purpose of further evaluation, the bending test of the original crankshaft is carried out, and failure mode analysis is made. The appropriate number of samples, the applied load, and the test time are computed. On the basis of the test results, Weibull analysis for the shape and scale parameters of the crankshaft is estimated. Likewise, the B10 life under 50% of the confidence level and the MTTF are exactly calculated, and the groundwork for improving the reliability of the crankshaft is laid. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Do-Hyun Jung received his B.S. and M.S. degrees in Mechanical Engineering from Ajou University in 1988 and 1990, respectively. He then obtained his Ph.D. degree from Changwon National University in 2006. Dr. Jung is currently an Adjunct Professor at the School of Mechanical Engineering of Sunmoon University, Korea. He also manages the Reliability Application Research Center of the Reliability Division of KATECH. Dr. Jung’s fields of study include fatigue, reliability, and remanufacturing issues.     

Localization of sarcoglycan, neuronal nitric oxide synthase, beta-dystroglycan, and dystrophin molecules in normal skeletal myofiber: triple immunogold labeling electron microscopy.

In order to investigate the mode of existence of the sarcoglycan complex, neuronal nitric oxide synthase (nNOS), beta-dystroglycan, and dystrophin in the normal skeletal myofiber, we examined the ultrastructural localization and mutual spatial relationship of nNOS, beta-dystroglycan, dystrophin, and the individual components of the sarcoglycan complex by using triple immunogold labeling electron microscopy. Each molecule of alpha-, beta-, gamma- and delta-sarcoglycans is located intracellularly or extracellularly near the muscle plasma membrane mostly in accordance with the sarcoglycan antigenic sites against which the antibodies were generated. The association of different two and/or three sarcoglycan molecules out of alpha-, beta-, gamma- and delta-sarcoglycan molecules was frequently observed. Each molecule of nNOS, beta-dystroglycan, and dystrophin was ultrastructurally noted along the cell surface of normal skeletal myofibers. Moreover, the close relation of a sarcoglycan molecule with beta-dystroglycan and dystrophin, and the association of nNOS with dystrophin were also confirmed ultrastructurally. Thus, this study demonstrated that the constituting molecules of the sarcoglycan complex, nNOS, beta-dystroglycan, and dystrophin existed in the form of a cluster at the normal muscle plasma membrane. The association of nNOS with dystrophin and its associated glycoproteins may form a macromolecular signaling complex at the muscle plasma membrane.     

网格曲面上的样条曲线阵列

提出一种流形网格曲面上曲线阵列复制方法,达到曲线重用与再设计的目的。网格曲面上的曲线用测地B样条表示,使对曲线的操作可以转换为对曲线控制顶点的操作;引入离散指数映射理论将给定的源曲线控制顶点映射到切空间,获得它们的法坐标,按照曲线阵列前后控制顶点法坐标保持不变的原则,建立曲线阵列前后控制顶点的对应关系,实现曲线的有规律多重复制。法坐标很好地保持了控制顶点之间的测地距离和相对位置关系,因而也保证了曲线阵列重用过程中的形状保持性。将曲线阵列时的位置与形状分开处理,使曲线生成仅与其所在的局部区域有关而与曲面的整体大小无关,既便于保证曲线的形状保持性,也减少了计算量。试验结果表明,所介绍方法健壮、有效,能满足曲面上曲线的交互设计要求。     

Future directions of fundamental research in additive tribochemistry

This paper reviews briefly the present state of fundamental research, in tribochemistry of load-carrying additives, including oiliness agents, organolsulphur, organochlorine, organophosphorus, organic borates and organometallic compounds. The emphasis is on the weak areas of investigation. It is revealed that the least understood mechanisms, such as the effect of additives on fretting wear, additive-material compatibility, the efficacy of antifatigue additives and the action of water-based fluid additives in metalworking, are the concern of overlapping spheres of learning. A cooperative effort by chemists, metallurgists and mechanical engineers would help overcome the difficulties posed by problems in areas beyond individual expertises. Some research projects for the future are also suggested.     

“老板文化”对“企业文化”的作用——也谈“企业文化”建设的认知

优秀企业的成长、发展、壮大,与其优秀的＂企业文化＂建设不无关系。任何企业都是有文化的,不存在没有文化的组织,只有不同文化的组织。衡量企业文化的标准,只有显著程度、优劣和现实性,而不是有或无。只要有人群存在,他们的行为就构成一定的文化。企业老板,是企业文化的倡导者和缔造者。老板对企业文化建设的影响很大。＂老板文化＂是＂企业文化＂的奠基石。因此,企业要创建优秀的企业文化,企业领导层首先要有优秀的＂老板文化＂。而随着企业的发展,企业所有员工共同参与讨论并提炼企业文化,逐步走向民主与开放。这时的企业文化更多的融入了集体的智慧,老板文化的作用会逐渐减小,所以企业文化又不单是老板文化。     

Electrospray mass spectrometry of phospholipids

Phospholipids play a central role in the biochemistry of all living cells. These molecules constitute the lipid bilayer defining the outer confines of a cell, but also serve as the structural entities which confine subcellular components. Mass spectrometry has emerged as a powerful tool useful for the qualitative and quantitative analysis of complex phospholipids, including glycerophospholipids and the sphingolipid, sphingomyelin. Collision induced decomposition of both positive and negative molecular ion species yield rich information as to the polar head group of the phospholipid and the fatty-acyl substituents esterified to the glycerophospholipid backbone. This review presents the current level of understanding of the mechanisms involved in the formation of various product ions following collisional activation of molecular ion species generated by electrospray ionization of the common glycerophospholipids, including phosphatidic acid, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidylglycerol, phosphatidylserine, cardiolipin, and sphingomyelin. Recent advances in the application of matrix assisted laser desorption ionization is also considered. Several applications of mass spectrometry applied to phospholipid analysis are presented as they apply to physiology as well as pathophysiology.     

SAGD采出液高压高频脉冲电脱水的试验研究

针对SAGD采出液乳化程度高、成分复杂的问题,该文采用高频高压脉冲方法对采出液进行试验研究,系统分析电压幅值、频率、占空比、脱水时间对脱水性能的影响规律。试验表明:电压幅值增加,聚结破乳效果提升,脱水功率随之升高,电压幅值过大时,脱水率和功率呈现降低的趋势;频率过大时,脱水率大幅降低,短路的出现使得功率大幅增长;占空比增加,极化变形程度增加,脱水率、脱水功率随之增加;占空比超过0.5,出现过度极化和电分散;2.5h以后,极化作用力显著减少,脱水率缓慢增大,3h以后呈现平稳的趋势。SAGD电脱最佳操作条件:电压幅值5.5k V,频率4k Hz,占空比0.5,时间3h。本文为特超稠油采出液的高效脱水奠定了基础。