关键词： 机械密封试验台   机械密封   动力机  

摘要： 螺杆膨胀动力机,其原理是以吸收工业企业所排放的余热、废热、废热气、冲渣废热水、减温减压蒸汽节流能量和排放的废热(如连排水排放)以及地热的能量、可以应用螺杆膨胀动力机来拖动负载(或者发电)等提供动力,达到环保、节能减排及提供廉价电力或动力的目标。

关键词： 流固耦合   界面模型   载荷转换   映射矩阵   水力机械  

摘要： 为解决水力机械流固耦合计算中载荷传递的问题,提出了一种新的界面模型。该模型包括流场载荷输出、载荷转换和固体场载荷自动施加三部分。流场载荷输出算法通过输出控制仅输出耦合界面上的流场网格节点压力信息,可以缩短下一步搜索时间并节省存储空间;载荷转换方法基于局部网格信息,对每个固体点考虑其相邻的流场三角形网格,采用邻近点加权平均法得到固体点的载荷,并将载荷转换的信息放在映射矩阵;固体场载荷自动施加算法根据固体网格节点排列顺序确定压力载荷施加表面,并生成压力载荷施加的命令流文件。最后将该模型应用于双吸离心泵叶轮的流固耦合特性分析中,结果表明,载荷转换误差在1%以内,该方法能够高效、高精度地处理不同网格体系间的载荷传递。

关键词： 工程机械行业   东方红柴油机   动力元件   上海新国际博览中心   宝马   展放   品牌   工程机械企业  

摘要： 1展会情况 “上海宝马工程机械展”是世界最大的工程机械展bauma在中国的延伸，同时也是2010年亚太地区最具影响力的国际性行业博览会。bauma China 2010暨第5届中国国际工程机械、建材机械、工程车辆及设备博览会于2010年11月23—26日在上海新国际博览中心召开。本届展会展示面积超过23万m^2，1800余家展商同台展出，是国内工程机械企业开拓世界之旅的绝佳舞台。

关键词： 随机振动   非线性   分叉  

摘要： 旋转机械长期运行时,会发生某种程度系统参数的变化,从而导致动力学特性的改变。对旋转机械轴承振动进行了现场监测,发现三种动力学效应:机器失效损坏、异常响声、边频。给出了异常响声和边频分叉的时间序列和频谱,认为这两种分叉使机器处于稳定状态,而失效损坏分叉是不稳定状态。

关键词： 工程机械行业   中国经济   机械产业   提速   助推   创新能力   高位运行   竞争力  

摘要： “十二五”时期，稳健向上的中国经济将为工程机械行业的发展提供重要而持续的动力，受益于此，加之企业创新能力及综合竞争力的不断提升，我国工程机械行业将继续保持高位运行。

关键词： Nickel aluminides   based on Ni3Al   Diffusion   Mechanical alloying and milling   Sintering  

摘要： We present the features of macrokinetics of phase formation during the solid-state synthesis in the mechanically milled 3Ni + Al mixtures. It was found that with milling time, the activation energy decreases down to anomalously low values, which is related to structural changes in the powder mixtures. A method was proposed to process thermograms of the synthesis in the thermal explosion mode and was used to study the kinetic function structure and its parameters in the system. The numerical processing of the experimental data shows that the kinetic function most adequately corresponds to the law of homogeneous kinetics of phase formation with the reaction order close to unity. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Cardiopulmonary resuscitation (CPR)   Mechanical resuscitation device   Manikin  

摘要： Purpose: The goal of this randomized, open, controlled crossover manikin study was to compare the performance of "Animax", a manually operated hand-powered mechanical resuscitation device (MRD) to standard single rescuer basic life support (BLS). Methods: Following training, 80 medical students performed either standard BLS or used an MRD for 12 min in random order. We compared the quality of chest compressions (effective compressions, compression depth and rate, absolute hands-off time, hand position, decompression), and of ventilation including the number of gastric inflations. An effective compression was defined as a compression performed with correct depth, hand position and decompression. Results: The use of the MRD resulted in a significantly higher number of effective compressions compared to standard BLS (67 +/- 34 vs. 41 +/- 34%, p < 0.001). In a comparison with standard BLS, the use of the MRD resulted in less absolute hands-off time (264 +/- 57 vs. 79 +/- 40 s, p < 0.001) and in a higher minute-volume (1.86 +/- 0.7 vs. 1.62 +/- 0.71, p = 0.020). However, ventilation volumes were below the 2005 ERC guidelines for both methods. Gastric inflations occurred only in 0 +/- 0.1% with the MRD compared to 3 +/- 7% during standard BLS (p < 0.001). Conclusion: Single rescuer cardio-pulmonary resuscitation with the manually operated MRD was superior to standard BLS regarding chest compressions in this simulation study. The MRD delivered a higher minute-volume but did not achieve the recommended minimal volume. Further clinical studies are needed to test the MRD's safety and efficacy in patients. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

关键词： Calcium carbonate  

摘要： polyester poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3/4HB) containing 5 mol% 4HB was composited with different calcium carbonate (CaCO3) fillers. The effect of CaCO3 contents on thermal properties, mechanical property, and crystallization kinetics was evaluated. The thermal stability of P3/4HB was reduced by mixing with CaCO3 particles. With increasing CaCO3 content, the elongation at break, tensile strength, and impact strength decrease;however, elastic modulus increases. When P3/4HB with 20 mol% 4HB was added into the P3/4HB/CaCO3 composite, the impact strength were enhanced significantly;however, the elongation at break and tensile strength were only slight to moderate improvements. However, when compared with nano-and light-CaCO3, heavy CaCO3 had the best mechanical properties. The nonisothermal and isothermal crystallization results demonstrated that the crystallization rate of P3/4HB was reduced and the highest crystallinity was obtained for all kinds of CaCO3 fillers at 40 phr content. POLYM. COMPOS., 32: 1134-1142, 2011. (C) 2011 Society of Plastics Engineers

关键词： atrial function   cardiac resynchronization therapy   strain echocardiography  

摘要： OBJECTIVES The aim of this study was to evaluate atrial and ventricular function in patients undergoing cardiac resynchronization therapy (CRT). BACKGROUND Right atrial pacing (AP) in CRT induces delays in electrical and mechanical activation of the left atrium. The influence of atrial sensing (AS) versus AP on ventricular performance in CRT and the mechanisms underlying the differences between AS and AP in CRT have not been fully elucidated. METHODS Fifty-five patients with heart failure undergoing CRT for 9 +/- 12.5 months and 22 control subjects without heart failure were enrolled. Conventional and tissue Doppler echocardiography was performed to examine atrial and ventricular mechanics and hemodynamic status. RESULTS The optimal atrioventricular interval was shorter in AS compared with AP mode (126 +/- 19 ms vs. 155 +/- 20 ms, p < 0.0001). Left ventricular (LV) outflow tract time-velocity integral (22 +/- 7 cm vs. 20 +/- 7 cm, p < 0.001), diastolic filling period (468 +/- 124 ms vs. 380 +/- 93 ms, p < 0.001), and global strain (-32 +/- 24% vs. -27 +/- 22%, p = 0.001) were greater in AS compared with AP mode. Atrial strain was higher in AS compared with AP mode in the right atrium (-28.2 +/- 8.6% vs. -22.6 +/- 7.6%, p = 0.0007), interatrial septum (-17.1 +/- 6.5% vs. -13.2 +/- 5.4%, p = 0.002), and left atrium (-16.4 +/- 11.0% vs. -13.6 +/- 8.5%, p = 0.02). There was no difference in intraventricular dyssynchrony but significantly lower atrial dyssynchrony in AS compared with AP mode (31 +/- 19 ms vs. 42 +/- 24 ms, p = 0.0002). CONCLUSIONS AS is associated with preserved atrial contractility and atrial synchrony, resulting in optimal LV diastolic filling, stroke volume, and LV systolic mechanics. This pacing mode maximizes LV performance and the hemodynamic benefit of CRT in patients with heart failure. (J Am Coll Cardiol Img 2011;4:691-8) (C) 2011 by the American College of Cardiology Foundation

关键词： LIGNINS   MECHANICAL pulping process   INDUSTRIAL wastes   FLY ash   ADSORPTION   DIFFUSION   SORBENTS   POLLUTANTS  

摘要： The possible application of adsorption for the removal of lignin-related material found in wastewater generated by mechanical pulping was investigated. Activated charcoal and fly ash were used as adsorbents in batch experiments. The lignin-related material exhibited properties well-suited for adsorption onto both adsorbents, although the sorption capacity of activated charcoal exceeds that of fly ash. The experimental data were fitted to pseudo-first- and pseudo-second-order rate kinetic expressions, and an attempt was made to find the rate-limiting step involved in the adsorption processes. The results showed that lignin adsorption onto both activated charcoal and fly ash follows pseudo-second-order rate kinetics and that both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Adsorption is an interesting option in advanced wastewater treatment, and fly ash appears to be a suitable low-cost adsorbent for recalcitrant organic pollutants. [ABSTRACT FROM AUTHOR]