MoSi2 samples were prepared by a self-propagating high-temperature synthesis (SHS) and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction ...MoSi2 samples were prepared by a self-propagating high-temperature synthesis (SHS) and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1) oil lubrication can obviously improve the tribological properties of MoSi2, 2) the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3) with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4) under oil lubrication the wear mechanism is mainly fatigue pitting.展开更多
目的系统评价促红细胞生成素(EPO)治疗急性颅脑损伤的有效性和安全性。方法计算机检索The Cochrane Li brary、Clinical Trials、Web of Science、PubMed、EMbase、中国生物医学文献数据库、中国知网数据库和万方数据库,检索年限均从建...目的系统评价促红细胞生成素(EPO)治疗急性颅脑损伤的有效性和安全性。方法计算机检索The Cochrane Li brary、Clinical Trials、Web of Science、PubMed、EMbase、中国生物医学文献数据库、中国知网数据库和万方数据库,检索年限均从建库至2018年5月。搜集EPO治疗急性颅脑损伤的临床随机对照试验,试验组采用EPO治疗,对照组采用安慰剂或空白对照。采用RevMan 5.3软件进行meta分析。结果纳入7项临床随机对照研究,共计1101例,试验组564例,对照组537例。meta分析显示:EPO显著降低病死率(RR=0.69;95%CI 0.51~0.94;P=0.02),不能改善神经功能(RR=1.28;95%CI 0.90~1.81;P=0.17),不增加深静脉血栓形成发生率(RR=1.00;95%CI=0.74~1.35;P=0.99)。结论EPO治疗急性颅脑损伤可以降低死亡率,无明显严重的不良反应,但不能改善神经功能。展开更多
基金Projects 50405041 supported by National Natural Science Foundation of China and 04C218 by Hunan Province Education Foundation of China
文摘MoSi2 samples were prepared by a self-propagating high-temperature synthesis (SHS) and a hot-press technique. The sliding friction and wear properties of intermetallic MoSi2 against AISI10045 steel under dry friction and oil lubrication conditions were investigated with a MRH-5A type ring-on-block friction and wear tester. The elemental composition, microstructure and worn surface morphology of the MoSi2 material were observed and analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthetic parameter pv value reflecting friction work, was used to discuss the tribological properties of MoSi2 material. The results show that 1) oil lubrication can obviously improve the tribological properties of MoSi2, 2) the bigger the pv value, the greater the antifriction and the abrasive resistance of MoSi2 under oil lubrication, 3) with an increase in the pv value, the wear mechanism of MoSi2 material under dry sliding friction is the fatigue fracture and adhesive wear and 4) under oil lubrication the wear mechanism is mainly fatigue pitting.
文摘目的系统评价促红细胞生成素(EPO)治疗急性颅脑损伤的有效性和安全性。方法计算机检索The Cochrane Li brary、Clinical Trials、Web of Science、PubMed、EMbase、中国生物医学文献数据库、中国知网数据库和万方数据库,检索年限均从建库至2018年5月。搜集EPO治疗急性颅脑损伤的临床随机对照试验,试验组采用EPO治疗,对照组采用安慰剂或空白对照。采用RevMan 5.3软件进行meta分析。结果纳入7项临床随机对照研究,共计1101例,试验组564例,对照组537例。meta分析显示:EPO显著降低病死率(RR=0.69;95%CI 0.51~0.94;P=0.02),不能改善神经功能(RR=1.28;95%CI 0.90~1.81;P=0.17),不增加深静脉血栓形成发生率(RR=1.00;95%CI=0.74~1.35;P=0.99)。结论EPO治疗急性颅脑损伤可以降低死亡率,无明显严重的不良反应,但不能改善神经功能。
