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针对医用植入支架管在临床使用过程中存在的体液结垢问题,研究医用聚氨酯支架管表面的化学法粗化及其润湿性。采用化学法粗化医用聚氨酯材料,测量粗化后聚氨酯材料的接触角和表面形貌,分析液滴重力对接触角的影响,并探讨影响粗化效果的因素,如粗化液的种类、粗化液混合比、粗化液浓度、粗化温度、粗化时间等对粗化后导管表面润湿性的影响。结果表明:聚氨酯材料表面接触角随着液滴重力的增加,呈先增大后减小的趋势;粗化有助于提高聚氨酯导管表面疏水性能,其中三氧化铬粗化后导管接触角比高锰酸钾粗化后接触角更大;接触角随着三氧化铬与浓硫酸混合比、粗化温度、粗化时间三者的增大,均呈现先增大后减小的趋势,而随着三氧化铬浓度的增大逐渐增大。得到最佳的粗化工艺参数为:三氧化铬与浓硫酸的混合比2∶1,三氧化铬浓度80 g/L,粗化温度50℃,粗化时间30 min。 相似文献
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根据液气两相双流体模型,提出了按各相流动密度分摊压力,以及在气泡粒径未知情况下,表述相间作用力的表达式,在此基础上提出了有限空间液-液气射流及射流泵流场数值模拟计算方法。 相似文献
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喷液单螺杆压缩机内液滴运动规律及其对传热的影响 总被引:5,自引:1,他引:4
建立了喷液单螺杆压缩机基元容积内液滴的空间运动学模型,并依此研究了压缩机转速、液滴尺寸、喷液速度及角度等参数与液滴在压缩腔内自由飞行时间的关系,同时从理论上分析了喷液参数对汽液换热的影响,并用实验加以验证。 相似文献
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本文介绍了自1927年以来世界有关国家在Ni-Fe合金电镀方面的属性取得的成就,详细论述了Ni-Fe合金电镀的电析机理和特点Ni-Fe合金的镀液组成,操作条件及Ni-Fe合金镀层的相结构、耐蚀性和磁性能。对Ni-Fe合金电镀在理论研究和生产实践方面都具有一定的参考价值。 相似文献
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利用相变参数测量、变温金相观察、X-射线衍射等方法研究了热循环对Cu-Zn-Al合金马氏体相变和双向记忆效应的影响。热循环使合金相变点升高,可逆马氏体量减少,记忆性能衰减,滞后环宽度变窄。在组织结构上,伴随着热循环,合金有序度降低,并出现高度稳定的残留马氏体。使晶粒粗化,提高合金Al质量分数,适当提高约束加热训练温度均可改善合金抗热循环性能。 相似文献
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本文对气液两相流体的润滑机理进行了试验研究和理论分析,在金属切削加工中应用了气液两相流体润滑技术,进行了切削温度,切削刀,光洁度等项目的对比试验,提出了气液两相流体润滑的新模型-气液两相膜,并推荐了分析两相膜粘度的关系式。 相似文献
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稀土添加剂对Ni—Fe合金镀液稳定性的影响 总被引:1,自引:0,他引:1
介绍了稀土添加剂对Ni-Fe合金镀液稳定性的影响,实验结果表明,稀土添加剂对镀液的稳定性有较明显的作用,而且用量少,没有副产物。 相似文献
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研究得出了液-液气射流泵的基本性能方程,与国外同类资料作了类比,导出了模型中各修正系数的表达式,经试验证实了模型的正确性,实验还发现二相液气射流泵与液体射流泵性能在极限工况上有很大的差异。 相似文献
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《Mechanical Systems and Signal Processing》2000,14(5):835-843
A new method, phase difference corrections method is developed to correct the frequency and phase of spectrum peak. The continuous time-domain signal is separated into two segments and fast Fourier translation (FFT) is carried out for them, respectively. The frequency and phase are corrected using the phase difference of corresponding discrete spectral lines. Furthermore, the amplitude can also be rectified using the formula of window function spectrum. This method, with good adaptability, high speed and accuracy, is theoretically simple. It can resolve the frequency by means of phase difference directly without the formula of window function. Simulation shows that the single-component frequency, phase and amplitude of theoretical signal can be corrected satisfactorily, with frequency error less than 0.0002 frequency resolution, phase 0.1° and amplitude 0.0002. If the signal involves noise, the mean corrected errors are less than 0.001 frequency resolution, 1° for phase, and 0.01 for amplitude, respectively, and the maximum corrected errors of one segment are less than 0.01 frequency resolution, 1° and 0.03, respectively. 相似文献
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NUMERICAL SIMULATION OF CHARGED GAS-LIQUID TWO PHASE JET FLOW IN ELECTROSTATIC SPRAYING 总被引:3,自引:0,他引:3
0 INTRODUCTIONThe technology of electrostatic spraying has beenwide applied in many fields such as spray coating,pesticide sPraying, dust control and so on. The wholeprocess of electrostatic spraying such as charging,transporting and depoSition on targets is closelyrelated to charged gas liquid twcaphase turbulent jetflow.Therefore, the study of charged two-phaseturbulent jet flow is the basis of the development ofelectrostatic spraying.As a result of the complexity of the gas-liquidinte… 相似文献
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Liu JinkunLiu QiangEr LianjieDepartment of Automatic Control Beijing University of Aeronauticsand Astronautics Beijing China 《机械工程学报(英文版)》2004,17(1):132-135
Flight simulator is an important device and a typical high performance position servo system used in the hardware-in-the-loop simulation of flight control system. Without using the future desired output, zero phase error controller makes the overall system's frequency response exhibit zero phase shift for all frequencies and a very small gain error at low frequency range can be achieved. A new algorithm to design the feedforward controller is presented, in order to reduce the phase error, the design of proposed feedforward controller uses a modified plant model, which is a closed loop transfer function, through which the system tracking precision performance can be improved greatly. Real-time control results show the effectiveness of the proposed approach in flight simulator servo system. 相似文献
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GUO Dongmei WANG Ming School of Physical Science Technology Nanjing Normal University Nanjing China 《机械工程学报(英文版)》2007,20(3):83-85
ASeblsf-tmraicxti:n gA innteewrf esreelnf-cme ioxcincgu rms iicnr oa -liansteerrf derioodmee t(eLrD b)a sbeyd r eofnl eecxtitnergn tahl ep lhiagshet fmroomdu ala tmioinrr oisr-plirkees etanrtgedet. in front of the laser. Sinusoidal phase modulation of the beam is obtained by an electro-optic crystal (EOC) in the external cavity. The phase of the interference signal is demodulated by Fourier analysis method. The combination of the modulation and demodulation decreases the sensitivity of the instru-ment to fluctuations of the laser power and the noise induced by environment. Experimentally, the new micro-interferometer is applied to measure the micro-displacement of a high precision commer-cial PZT with an accuracy of <10 nm. 相似文献