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81.
经济型矿用无极绳绞车控制装置设计 总被引:1,自引:0,他引:1
介绍了经济型矿用无极绳绞车控制装置的组成、工作原理、硬件及软件设计。该装置以主控制箱为核心,可实时检测速度信号和绞车运行信息,并可将信息实时显示在触摸显示屏上,具有绞车启停、正反向控制、调速和自动加减速控制、机头机尾过卷、启车预警、岔道告警等功能;当绞车出现故障时能够立即停车,确保绞车安全运行。该装置既可以作为无极绳绞车的软启或直启控制系统,又可以作为无极绳绞车变频控制系统。 相似文献
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Paul Feautrier 《International journal of parallel programming》1992,21(6):389-420
This paper extends the algorithms which were developed in Part I to cases in which there is no affine schedule, i.e. to problems whose parallel complexity is polynomial but not linear. The natural generalization is to multidimensional schedules with lexicographic ordering as temporal succession. Multidimensional affine schedules, are, in a sense, equivalent to polynomial schedules, and are much easier to handle automatically. Furthermore, there is a strong connection between multidimensional schedules and loop nests, which allows one to prove that a static control program always has a multidimensional schedule. Roughly, a larger dimension indicates less parallelism. In the algorithm which is presented here, this dimension is computed dynamically, and is just sufficient for scheduling the source program. The algorithm lends itself to a divide and conquer strategy. The paper gives some experimental evidence for the applicability, performances and limitations of the algorithm. 相似文献
84.
研究提高室内定位精度问题,终端定位是无线传感器网络中的关键技术之一,由于室内环境复杂,遮挡物较多,使定位信号减弱。传统RSSI的定位算法使目前室内定位不能满足要求。为解决RSSI测量方法误差较大的问题,提出一种将RSSI测量值与波束切换智能天线相结合的联合定位算法。同时引入了网格和半波瓣的概念,利用波束切换智能天线将信号最强的波束对准终端,同时终端上报RSSI值来联合定位。仿真结果表明,在获得相同定位精度的条件下,方法避免了样本采集,不需要训练时间,为定位精度设计提供了借鉴。 相似文献
85.
转换开关是用在工业生产自动流水线机械手中一种易磨损和大量消耗的塑料制品,以前依靠外国进口,花费了大量外汇。由于转换开关的精度极高,甚至超过金属件的制造精度。故不仅要求制品在成型加工过程中不能有微小的变形,甚至需要严格控制塑料的收缩量。使得所有成型孔的精度达到IT6级以上,平面度不大于0.02 mm,圆柱度不大于0.01 mm。通过对亚光微珠增强聚碳酸脂改性材料的选择,实现控制了制品变形量和提高了耐磨性的目的,通过超高精度孔的二次限制工艺的实施,使得制品孔的精度可达到IT4级以上,圆柱度为0.002 mm以内。国产转换开关完全取代了进口产品,且其精度和寿命远高于进口产品,为超高精度注射件加工创出了一种新方法,也为有关单位节约了大量外汇。 相似文献
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Olga V. Balberova Evgeny V. Bykov Natalia A. Shnayder Marina M. Petrova Oksana A. Gavrilyuk Daria S. Kaskaeva Irina A. Soloveva Kirill V. Petrov Elena Y. Mozheyko German V. Medvedev Regina F. Nasyrova 《International journal of molecular sciences》2021,22(12)
Regular physical activity in cyclic sports can influence the so-called “angiogenic switch”, which is considered as an imbalance between proangiogenic and anti-angiogenic molecules. Disruption of the synthesis of angiogenic molecules can be caused by local changes in tissues under the influence of excessive physical exertion and its consequences, such as chronic oxidative stress and associated hypoxia, metabolic acidosis, sports injuries, etc. A review of publications on signaling pathways that activate and inhibit angiogenesis in skeletal muscles, myocardium, lung, and nervous tissue under the influence of intense physical activity in cyclic sports. Materials: We searched PubMed, SCOPUS, Web of Science, Google Scholar, Clinical keys, and e-LIBRARY databases for full-text articles published from 2000 to 2020, using keywords and their combinations. Results: An important aspect of adaptation to training loads in cyclic sports is an increase in the number of capillaries in muscle fibers, which improves the metabolism of skeletal muscles and myocardium, as well as nervous and lung tissue. Recent studies have shown that myocardial endothelial cells not only respond to hemodynamic forces and paracrine signals from neighboring cells, but also take an active part in heart remodeling processes, stimulating the growth and contractility of cardiomyocytes or the production of extracellular matrix proteins in myofibroblasts. As myocardial vascularization plays a central role in the transition from adaptive heart hypertrophy to heart failure, further study of the signaling mechanisms involved in the regulation of angiogenesis in the myocardium is important in sports practice. The study of the “angiogenic switch” problem in the cerebrovascular and cardiovascular systems allows us to claim that the formation of new vessels is mediated by a complex interaction of all growth factors. Although the lungs are one of the limiting systems of the body in cyclic sports, their response to high-intensity loads and other environmental stresses is often overlooked. Airway epithelial cells are the predominant source of several growth factors throughout lung organogenesis and appear to be critical for normal alveolarization, rapid alveolar proliferation, and normal vascular development. There are many controversial questions about the role of growth factors in the physiology and pathology of the lungs. The presented review has demonstrated that when doing sports, it is necessary to give a careful consideration to the possible positive and negative effects of growth factors on muscles, myocardium, lung tissue, and brain. Primarily, the “angiogenic switch” is important in aerobic sports (long distance running). Conclusions: Angiogenesis is a physiological process of the formation of new blood capillaries, which play an important role in the functioning of skeletal muscles, myocardium, lung, and nervous tissue in athletes. Violation of the “angiogenic switch” as a balance between proangiogenic and anti-angiogenic molecules can lead to a decrease in the functional resources of the nervous, musculoskeletal, cardiovascular, and respiratory systems in athletes and, as a consequence, to a decrease in sports performance. 相似文献
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针对采用带头与卷取机芯轴橡胶套筒定位区动态接触的传统自动定位技术控制效果不好而带来带头印缺陷的问题,对其产生原因进行了分析,这是因为不同规格、钢种带钢的工艺参数不同,带钢穿带过程中在传送辊上的打滑量不同,在传输通道上的下垂量不同,带头到达卷取机芯轴定位区时计算带头位置与实际带头位置存在不稳定的偏差,因此带头定位精度不稳定。为此,开发了双动态自动定位技术,穿带过程中预留了足够的带钢打滑及下垂富余量,且带头与定位区中心线在助卷皮带咬入口静止状态下接触,消除了影响带头定位精度的主要因素,带头定位精度能稳定在±15 mm的误差范围内。实际应用效果表明,该方法可行、实用。 相似文献