履带式管道施工车辆与吊管机技术安全性综合分析

吊管机、焊接车是在推土机的基础上发展起来的履带式管道工程车辆,施工环境、作业方式特殊,整机稳定性、安全性相对较差.根据设备关联性和工况近似性,详细分析了国内外推土机、起重机和吊管机发展与技术状况,讨论了目前履带式管道施工车辆坡面驻留、防滑、抗倾覆能力的不足.为提高安全性、稳定性和环境适应性,根据吊管机工作环境与结构特点...     

现场配管的压力试验

目前液压系统安装现场基本上不进行现场配管的压力试验,给设备使用带来了安全隐患。特别是在目前液压设备高压趋向下,必须对设备现场配管的压力试验提出要求。     

农村住宅节能产业“联产联销”管理模式

在“城镇化”和“低碳经济”两大社会背景下,住宅节能推广迫在眉睫.提出了一种适合于农村地区住宅节能推广和产业发展的“联产联销”管理模式,探索了农户与企业、企业与企业联合生产、共同销售为主要形式的产业运作方式,并详细分析了该模式的运行机制和应用价值.     

水煤气净化系统氨积累处理方法

对水煤气净化系统氨积累成因进行分析,由于流体流动边界层的存在,氨与部分冷凝水在换热器管程内壁反应形成盐溶液并在管程内冷却结晶,从而造成铵盐结晶.从能量利用和水的平衡进行分析,提出改进措施,为合成氨装置技改提供参考.     

工业废水氯碱样中COD的测定方法

探讨了工业废水氯碱样中COD的2种测定方法,重铬酸钾法和20 min快速密闭催化消解法。实际情节况表明,20 min快速密闭催化消解法更适合黑龙江昊华化工公司的工业废水氯碱样中COD的测定。     

基于IPC的开放式工业机器人控制系统研究

开放性是现代机器人控制系统的实现目标之一。开放式工业机器人控制系统采用基于工业计算机（IPC）结合运动控制卡的结构形式,并借鉴ORC（Open Robot Controller）等典型的机器人控制系统软件体系结构设计了分层模块化的软件系统,使得现有的机器人控制系统只需要做少量的修改就能应用到不同的场合。     

Estimating contrast transfer function and associated parameters by constrained non-linear optimization

The three-dimensional reconstruction of macromolecules from two-dimensional single-particle electron images requires determination and correction of the contrast transfer function (CTF) and envelope function. A computational algorithm based on constrained non-linear optimization is developed to estimate the essential parameters in the CTF and envelope function model simultaneously and automatically. The application of this estimation method is demonstrated with focal series images of amorphous carbon film as well as images of ice-embedded icosahedral virus particles suspended across holes.     

Influence of stress and stress-protecting factors on rat tolerance to cold and efficiency of rat adaptation to cold]

The adaptive characteristics of the body, including the specific features of increased cold resistance upon repeated exposures to cold, are determined not only by the properties of thermogenic structures themselves, but largely depend on the contribution of the central mechanisms which control the processes of habituation and mobilization of functions. The experiments revealed an increase in cold resistance in rats after preexposure to cold. Immobilization stress prior to training cold significantly decreased rapid cold resistance in the animals, but increased the training effect of the first cooling. On the contrary, chlordiazepoxide increased cold resistance during the first cooling. Testing of the untreated animal showed no effect of training. No adaptive changes in cold resistance occurred in rats with impaired amygdaloid complex. Analyzing adrenal catecholamines revealed a significant elevation of dopamine concentrations in the rats exposed to cold. Hypothalamic catecholamines did not change with cold and serotonin in intact rats and 5-hydroxyindoleacetic acid in amygdalectomized rats substantially increased.     

Myocardial infarct and geomagnetic disturbances: analysis of data on morbidity and mortality

BACKGROUND: There is increasing evidence that the most effective way to improve delivery of preventive services in primary care is to establish organized preventive service systems. This study tests the hypothesis that a managed care organization (MCO) can help its contracted private primary care clinics to develop such systems. METHODS: Forty-four primary care clinics contracting with two large MCOs were randomized to a comparison (C) or an intervention (I) group. Group (I) clinic team leaders received training plus ongoing consultation and networking. Personnel at all 44 clinics completed surveys prior to and at the end of the intervention to measure adoption of the improvement process and the prevention system. RESULTS: All 22 (I) clinics identified teams that appeared to follow the seven-step improvement process. The mean numbers of system processes were identical at baseline, 11.2 (I) vs 12.1 (C), while after the intervention this had changed to 25.8 in (I) clinics vs 11.3 in (C) (P = 0.022). CONCLUSIONS: With training and assistance, interested primary care clinic teams will establish functioning CQI teams that will produce a substantial increase in the presence of functional prevention system processes. Whether this change is sufficient to increase the rates of preventive services remains to be documented.     

An experimental model of sudden death due to low-energy chest-wall impact (commotio cordis)

BACKGROUND: The syndrome of sudden death due to low-energy trauma to the chest wall (commotio cordis) has been described in young sports participants, but the mechanism is unknown. METHODS: We developed a swine model of commotio cordis in which a low-energy impact to the chest wall was produced by a wooden object the size and weight of a regulation baseball. This projectile was thrust at a velocity of 30 miles per hour and was timed to the cardiac cycle. RESULTS: We first studied 18 young pigs, 6 subjected to multiple chest impacts and 12 to single impacts. Of the 10 impacts occurring within the window from 30 to 15 msec before the peak of the T wave on the electrocardiogram, 9 produced ventricular fibrillation. Ventricular fibrillation was not produced by impacts at any other time during the cardiac cycle. Of the 10 impacts sustained during the QRS complex, 4 resulted in transient complete heart block. We also studied whether the use of safety baseballs, which are softer than standard ones, would reduce the risk of arrhythmia. A total of 48 additional animals sustained up to three impacts during the T-wave window of vulnerability to ventricular fibrillation with a regulation baseball and safety baseballs of three degrees of hardness. We found that the likelihood of ventricular fibrillation was proportional to the hardness of the ball, with the softest balls associated with the lowest risk (two instances of ventricular fibrillation after 26 impacts, as compared with eight instances after 23 impacts with regulation baseballs). CONCLUSIONS: This experimental model of commotio cordis closely resembles the clinical profile of this catastrophic event. Whether ventricular fibrillation occurred depended on the precise timing of the impact. Safety baseballs, as compared with regulation balls, may reduce the risk of commotio cordis.