一种煤气交换旋塞加油润滑装置

<正>专利号:ZL01274457.3专利权人:宝钢集团上海梅山有限公司发明(设计)人:孙建福本实用新型涉及一种加油润滑装置,特别涉及一种焦炉加热用煤气交换旋塞(考克)加油润滑装置。解决了已有加热煤气考克因润滑点缺油,造成加热煤气泄漏的缺陷。其技术方案是:一种煤气交换旋塞加油润滑装置,包括若干考克,其特征是该装置还包括电动机、驱动干油泵、机械式自动换向     

全数字同步电动机励磁控制新技术的应用

本文分析了同步电动机励磁装置技术性能好坏对同步电动机起动、运行造成的影响,分析目前同步电动机存在的主要问题,介绍了国内最新颖的微机晶闸管励磁控制装置的技术特点及包钢的应用情况.     

智能型电动机管理器的应用与研究

对适合大中型电动机保护监控管理的469电动机智能管理器(469 Motor Management Relay)进行了综合分析,详细分析了该装置独特的智能热容量保护和电动机起动保护,同时简述了该装置主要功能,指出了使用该装置的注意事项.     

B-DP节电优化装置在电动机中的应用

本文分析了B-DP电动机节电优化装置的特点、性能及参数,结合矿山设备电动机的实际工况,阐述了该装置在矿山设备中的应用实践及效果。     

同步电动机励磁系统故障分析及改造

同步电动机具有运行稳定、输出功率大等优点,特别是能向电网发送无功功率,支持电网电压,提高功率因数。但由于同步电动机的频繁损坏,直接影响安全、经济及稳定运行,文章阐述同步电动机频繁损坏的根本原因不在电动机本身,而在于励磁装置技术性能差。针对励磁装置技术性能的缺陷,提出切实可行,行之有效的改造技术措施。     

合金钢棒材生产线半连轧可逆式粗轧机主传动系统设计方案选择

根据合金钢棒材生产工艺的特点及粗轧机对传动系统的要求,结合作者多年设计和实践经验,介绍了半连轧可逆式粗轧机主传动系统设计时,如何选择变频装置、传动电动机、整流变压器、电源补偿装置,重点对比分析了三电平交-直-交变频装置和交-交变频装置的特点及性能价格、同步电动机和异步电动机的结构和性能参数以及无功补偿和谐波补偿的特点,最终给出了选择建议。     

全数字直流调速装置在轧机压下传动中的应用

西门子数字式直流调速装置具有参数设置简便、功能完善等特点。利用该装置的主从传动功能,来控制轧机压下电动机,可实现两台直流电动机同轴传动时同步均载。     

同步电动机变频起动装置的应用及典型故障案例

某烧结厂两台主排风机容量大,分别由两台大容量同步电动机驱动。一套交直交电流型变频装置分别起动两台主排风机,当加速到同步速后,通过同步并网装置调整后,同步电动机几乎无冲击切换到工频运行。介绍了同步电动机负载换相变频起动装置的换流原理,主回路结构,详细介绍变频起动过程中系统各部分之间的协调控制;在从变频向工频切换过程中,整步并网装置的控制方法,并结合几个典型故障案例,介绍了同步电动机变频起动装置故障处理的思路及方法。     

高压大功率交流电动机智能化应用

根据电解质导电特性、电机拖动理论和Matlab液态智能软起动计算机仿真技术研制开发出的高压电动机液态智能软起动装置实现了高压大功率交流电动机的恒流软起动。介绍了GZYQ液态软起动装置的性能特点及其在大中型高压交流电动机上的应用。     

攀钢炼铁厂6#烧结抽烟机改造实践

根据电解质导电特性、电机拖动理论和Madab液态智能软起动计算机仿真技术研制开发出的高压电动机液态智能软起动装置实现了高压大功率交流电动机的恒流软起动。介绍了GZYQ液态软起动装置的性能特点及其在大中型高压交流电动机上的应用。     

The response of Golgi tendon organs to single motor unit contractions

1. Cross-correlation analysis has been used to quantify the responses of cat soleus tendon organs to repetitive twitch contractions of: (a) different motor units within the muscle, (b) single motor units at different muscle lengths, and (c) single motor units when the pulse-train pattern of stimulation delivered to the motor unit axon was altered. 2. Ib afferents were observed which responded to each of several hundred successive motor unit twitches with identical numbers of spikes and with relatively invariant latencies. 3. The present results show that tendon organs are sensitive to subtle alterations in motor unit twitch wave form and amplitude, and that this sensitivity is reflected in the precise timings of their afferent discharge. 4. Examination of these tendon organ responses indicates that the forces produced by single motor units couples to the receptor capsule are well above threshold. Calculations based on these results, and earlier soleus motor unit and muscle fibre data, suggest that the absolute force threshold for tendon organs may be as little as 4 mg, which is less than the estimated minimum twitch force generated by individual soleus muscle fibres. 5. Considering the number of tendon organs in a muscle, and the likelihood that every motor unit is connected with at least one receptor, the sensitivity of tendon organs ensures that every twitch of every motor unit will be reflected in the population of afferent signals projecting to the spinal cord.     

A quantitative electrophysiological study of acute idiopathic polyneuritis

The motor unit content and the dimensions of individual motor unit action potentials were studied in 17 patients with acute idiopathic polyneuritis from one week to 9 1/2 years after the onset of the illness. An initial decrease in motor unit numbers is followed by a progressive increase with the passage of time from the onset of the illness. The latencies, areas, amplitudes, and durations of individual motor unit potentials were increased above normal values. The results suggest the presence of significant axonal damage in the majority of cases of acute idiopathic polyneuritis. The intramuscular nerve fibres are the site of most severe electrophysiological dysfunction in this study.     

Organization of single motor units in feline sartorius

1. We depleted single motor units in feline sartorius muscles of glycogen by stimulating their motoneurons intracellularly. We mapped the intramuscular distribution of depleted fibers by inspecting histological cross-sections throughout the length of sartorius. 2. We selected ten depleted motor units for detailed study and quantitative analysis. Nine motor units were located in the anterior head of sartorius. One was located in a muscle whose distal half appeared to have been damaged some time before the acute experiment. A single motor unit was located in the medial head of sartorius. 3. Five motor units were composed of fast-twitch glycolytic (FG) muscle fibers, two of fast-twitch oxidative glycolytic (FOG) muscle fibers, and three of slow-twitch oxidative (SO) muscle fibers. Estimates of the numbers of depleted fibers in motor units of anterior sartorius indicated that FG motor units were larger (mean 566 fibers) than FOG and SO motor units (SO mean 190, FOG mean 156 fibers). The SO motor unit in the damaged muscle had 550 fibers. One motor unit depleted in the medial head of sartorius had 270 fibers with FG profiles. 4. Muscle fibers belonging to each anterior motor unit were never distributed throughout the whole cross-section of anterior sartorius at any proximodistal level. Furthermore, fibers were distributed nonuniformly along the proximodistal axis of the muscle. In most muscles at least a few depleted fibers were found at all proximodistal levels. However, in one normal muscle and the damaged muscle, depleted fibers were confined to the proximal end. 5. The fibers in the medial motor unit were confined to a strip that did not extend across the whole cross-section of the muscle head. Fibers within this strip were scattered quite evenly from origin to insertion. This medial FG motor unit occupied a smaller territory and contained fewer fibers than anterior motor units of the same histochemical type. 6. These results show that sartorius motor units are not distributed uniformly in the mediolateral plane; those in anterior sartorius were distributed asymmetrically in the proximodistal axis as well. This finding has important functional implications for the way in which we model force development and transmission in sartorius and other long muscles.     

Adaptations of rat lateral gastrocnemius motor units in response to voluntary running

This study investigated the effects of 12 wk of voluntary wheel running on motor units from rat lateral gastrocnemius. Motor units were isolated via ventral root splitting (L5) from active or sedentary rats and were classified into slow, fast-fatigue-resistant, and fast-fatigable (FF) units. An overall increase in mean motor unit tetanic tension (35%) was accompanied by a decrease in mean motor unit fatigue resistance (-10%). These adaptations were localized in the fast unit population but varied among fast motor unit subtypes. The overall increase in tetanic force was due primarily to increases in fast-fatigue-resistant units (300%), whereas changes in fatigue resistance (-43%) were confined to FF units. However, the changes seen with activity may have been partly obscured by classifying fast motor units based on fatigability, since a significant increase in tetanic force accompanied by a decreased twitch one-half relaxation time was apparent in units falling in the midrange of the tetanic force continuum and included a number of FF units. These data provide direct demonstration of nonuniform motor unit adaptations subsequent to increases in normal functional activity.     

移动机械电缆卷盘全新控制技术

一种基于二维模糊控制的全新技术,可防止电缆过拉伸。系统由PLC单元、力矩电动机控制单元和电缆卷筒构成。系统通过电缆拉力一电压模糊控制策略表的查询和输出,把所需的输出值施加到力矩电动机控制单元的电压输入端,使力矩电动机输出的转速和转矩自动保持与当时电缆卷盘所需的转速和转矩相匹配,以保证电缆的正常收／放,避免电缆在收放过程中因拉力过大变形或被拉断。     

电液比例控制技术在开卷机机组中的应用

着重介绍电液比例控制技术在液压驱动开卷机组控制中的成功运用。运用电液比例控制技术是机列恒速度和恒张力功能得以实现的关键保证。电液比例控制液压驱动与传统的直流电机驱动相比,体现了当今世界机、电、液一体化的发展方向。其机械设备结构简单、控制方便     

VK85S空气压缩机电机振动故障分析

通过对VK85S空压机组振动故障诊断分析和较长时间的检查,找出了引起电机轴承剧烈振动的真正原因是机组共振,对电机基础和压缩机基础的两次加固处理最终消除了故障。     

Anatomy of upper extremity skin flaps

This article reviews some recent applications of time and frequency domain cross-correlation techniques to human motor unit recording. These techniques may be used to examine the pre-synaptic mechanisms involved in control of motoneuron activity during on-going motor tasks in man without the need for imposed and artificial perturbations of the system. In this review we examine, through several examples, areas in which insights have been gained into the basic neurophysiological processes that bring about motoneuron firing in man and illustrate how these processes are affected by central nervous system pathology. We will demonstrate that synchronization and coherence may be revealed between human motor unit discharges and give examples that support the hypothesis that these phenomena are generated by activity in a focused common corticospinal input to spinal motoneurons. Disruption of central motor pathways due to diseases of the nervous system leads to pathophysiological alterations in the activity of these pre-synaptic motoneuron inputs that can be revealed by cross-correlation analysis of motor unit discharges. The significance of these studies and outstanding questions in this field are discussed.     

Forcing the issue of physician-assisted suicide. Impact of the Kevorkian case on the euthanasia debate

In this review article we have attempted to provide an overview of the various forms of activity-dependent interactions between motoneurones and muscles and its consequences for the development of the motor unit. During early development the components of the motor unit undergo profound changes. Initially the two cell types develop independently of each other. The mechanisms that regulate their characteristic properties and prepare them for their encounter are poorly understood. However, when motor axons reach their target muscles the interaction between these cells profoundly affects their survival and further development. The earliest interactions between motoneurones and muscle fibres generate a form of activity which is in many ways different from that seen at later stages. This difference may be due to the immature types of ion channels and neurotransmitter receptors present in the membranes of both motoneurones and muscle fibres. For example, spontaneous release of acetylcholine may influence the myotube even before any synaptic specialization appears. This initial form of activity-dependent interaction does not necessarily depend on the generation of action potentials in either the motoneurone or the muscle fibre. Nevertheless, the ionic fluxes and electric fields produced by such interactions are likely to activate second messenger systems and influence the cells. An important step for the development of the motor unit in its final form is the initial distribution of synaptic contacts to primary and secondary myotubes and their later reorganization. Mechanisms that determine these events are proposed. It is argued that the initial layout of the motor unit territory depends on the matching of immature muscle fibres (possibly secondary myotubes) to terminals with relatively weak synaptic strength. Such matching can be the consequence of the properties of the muscle fibre at a particular stage of maturation which will accept only nerve terminals that match their developmental stage. Refinements of the motor unit territory follows later. It is achieved by activity-dependent elimination of nerve terminals from endplates that are innervated by more than one motoneurone. In this way the territory of the motor unit is established, but not necessarily the homogeneity of the physiological and biochemical properties of its muscle fibres. These properties develop gradually, largely as a consequence of the activity pattern that is imposed upon the muscle fibres supplied by a given motoneurone. This occurs when the motor system in the CNS completes its development so that specialized activity patterns are transmitted by particular motoneurones to the muscle fibres they supply.(ABSTRACT TRUNCATED AT 400 WORDS)     

Motor unit recruitment during prolonged isometric contractions

Motor unit recruitment patterns were studied during prolonged isometric contraction using fine wire electrodes. Single motor unit potentials were recorded from the brachial biceps muscle of eight male subjects, during isometric endurance experiments conducted at relative workloads corresponding to 10% and 40% of maximal voluntary contraction (MVC), respectively. The recordings from the 10% MVC experiment demonstrated a characteristic time-dependent recruitment. As the contraction progressed both the mean number of motor unit spikes counted and the mean amplitude of the spikes increased significantly (P < 0.01). This progressive increase in spike activity was the result of a discontinuous process with periods of increasing and decreasing activity. The phenomenon in which newly recruited motor units replace previously active units is termed "motor unit rotation" and appeared to be an important characteristic of motor control during a prolonged low level contraction. In contrast to the 10% MVC experiment, there was no indication of de novo recruitment in the 40% MVC experiment. Near the point of exhaustion a marked change in action potential shape and duration dominated the recordings. These findings demonstrate a conspicuous difference in the patterns of motor unit recruitment during a 10% and a 40% MVC sustained contraction. It is suggested that there is a close relationship between intrinsic muscle properties and central nervous system recruitment strategies which is entirely different in fatiguing high and low level isometric contractions.