斜井分层注水工艺研究与应用

常规偏心注水管柱及配套的钢丝绳投捞工艺不满足大斜度、小卡距的斜井注水要求,为此研究了斜井分层注水工艺技术。该工艺的配套管柱主要由Y341液压注水封隔器、旋转滑块扶正器、桥式同心配水器及测调系统等组成。配水工作筒和可调水嘴一体化设计,不需要进行水嘴投捞工作,改善了测调过程中注入水的过流能力,提高了测调准确率。现场应用结果表明,该工艺在大斜度情况下可实现正常注水,大大提高测调效率与成功率,满足薄夹层注水时的调配要求。

平板型阶跃式变阻抗线特性

介绍了变阻抗线的工作原理,给出了类Blumlein线结构变阻抗线的倍压特性,变阻抗线能够实现能量的完全传输,输出电压为输入电压的(n+1)/2倍;以平板结构为例研究了变阻抗线中的阻抗偏差问题:传输线实际阻抗较理论设计值偏大,各级的偏差基本在20%以内;通过电磁仿真研究了三级类Blumlein线结构变阻抗线中各级阻抗偏差对于倍压系数的影响,在阻抗偏差范围内,倍压系数随着阻抗的增大而减小,倍压系数在1.9～2.1范围内,给出倍压系数受各级阻抗偏差的影响规律;设计了三级类Blumlein线结构平板传输线进行实验,输出电压为3833V,与理论设计相符。

Assessment of right ventricular afterload by pressure waveform analysis in acute pulmonary hypertension

AIM: To characterize hydraulic right ventricle (RV) af- terload by pulmonary arterial pressure waveform analy- sis in an acute pulmonary hypertension (PH) model. METHODS: Pulmonary artery (PA) flow and pressure were recorded in six anesthetized sheep. Acute iso- baric PH was induced by phenylephrine (active) and PA mechanical constriction (passive). We estimated the amplitude of the forward and reflected pressure waves according to the inflection point. In most cases the in- flection pressure was smooth, thus the inflection point was defined as the time at which the first derivative ofpulmonary arterial pressure reached its first minimum. We calculated the input and characteristic (Z C , time- domain Li method) impedances, the capacitance index (stroke volume/pulse pressure), the augmentation index (AI) (reflected pressure/pulse pressure), the frac- tional pulse pressure (pulse pressure/mean pressure) and the wasted energy generated by the RV due to wave reflection during ejection (E W ). RESULTS: Pulse pressure, fractional pulse pressure, AI and Z C increased and capacitance index decreased during passive PH with respect to control (P < 0.05). In contrast, Z C and the capacitance index did not change and E W and the AI decreased during active PH. Pulse pressure correlated with E W and Z C and the AI was cor- related with E W (r > 0.6, P < 0.05). CONCLUSION: PA pressure waveform analysis al- lows the quantification of the dynamic RV afterload. Prospective clinical studies will be necessary to validate this time-domain approach to evaluate the dynamic RV afterload in chronic PH.

TMT异质性、战略变革与绩效改善的关系研究——基于绩效下滑的非多元化企业的数据实证

本文基于高阶梯队理论,针对以往TMT研究的关键问题,探讨绩效下滑的非多元化企业CEO继任后,TMT异质性、战略变革和绩效改善的关系。本文选取了沪深两市2005-2013年相关数据为研究变量,对2008-2010期间发生CEO变更的145家绩效下滑的非多元化企业进行实证研究,结果表明,TMT任期异质性对战略变动有显著负向影响,战略变动对企业绩效变化没有显著影响,战略背离对企业绩效变化有显著负向影响。当我们探索性的测量战略变革的方向时,发现战略变动与企业绩效变化呈U型关系,战略背离与企业绩效变化呈倒U型关系。本研究不仅为绩效下滑的非多元化企业转型战略研究提供一个新的视角,而且为绩效下滑企业选择高管团队提供了决策的依据。

尺寸偏差作用下角接触球轴承载荷分布研究

滚动轴承载荷分布的求解直接关系轴承承载能力、润滑特性、疲劳寿命等性能指标的计算。针对实际加工过程中存在的尺寸偏差,提出了考虑滚动体尺寸偏差的角接触球轴承载荷分布计算模型,分析了尺寸偏差大小、位置、数目、分布方式对轴承载荷分布的影响以及不同游隙下尺寸偏差的影响效果。通过对7218B型角接触球轴承的计算分析得出如下结论:对单个滚动体尺寸偏差而言,滚动体载荷变动量与尺寸偏差值呈线性关系,与滚动所处周向位置相关,但与轴承游隙无关;对多滚动体尺寸偏差而言,尺寸偏差滚动体的分布方式及相对大小均会对载荷分布产生重要影响。