标引深度(depth of indexing)的论题在相当多的著述中涉及,然而,见智见仁、众说纷纭;有的论者对标引系统的评述似乎故意避开了这个概念,有的干脆则认定标引深度易于导致紊乱,好象这个概念并非必不可少。我们认为:在析解文献主题及向受...标引深度(depth of indexing)的论题在相当多的著述中涉及,然而,见智见仁、众说纷纭;有的论者对标引系统的评述似乎故意避开了这个概念,有的干脆则认定标引深度易于导致紊乱,好象这个概念并非必不可少。我们认为:在析解文献主题及向受控语言转换的过程中,对文献论题的确认,尽管源于贯串检索系统全过程的各个或隐或显的因素的交互制牵、而变得有点扑朔迷离;展开更多
Based on my teaching and working experience in Europe, I have made a comparison between the Chinese and European patients in acupuncture treatment, and hope it is of some significance in acupuncture clinical practice.
This study addresses current status of ESSQ management and integration in steel production organisation. The idea is to benchmark maturity levels with the leading Finnish international companies. The examination has b...This study addresses current status of ESSQ management and integration in steel production organisation. The idea is to benchmark maturity levels with the leading Finnish international companies. The examination has been done in compliance with applied maturity model developed by the target corporation. When examining the benchmarked companies through the ESSQ framework, we found that a similar framework cannot be found in any other company as such; instead, operations are distributed under different organisations. Although many sources criticise system-based development, the results of this study indicate that it is nevertheless an efficient way to develop operations.展开更多
Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.Ho...Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.However,fusion welding of aluminum alloys is challenging due to several factors,including the presence of non-heat-treatable alloys,porosity,solidification,and liquation of cracks.Many manufacturers adopt conventional in-air friction stir welding(FSW)to weld metallic alloys and dissimilar materials.Many researchers reported the drawbacks of this traditional in-air FSW technique in welding metallic and polymeric materials in general and aluminum alloys and aluminum matrix composites in specific.A number of FSW techniques were developed recently,such as underwater friction stir welding(UFSW),vibrational friction-stir welding(VFSW),and others,for welding of aluminum alloy joints to overcome the issues of welding using conventional FSW.Therefore,the main objective of this review is to summarize the recent trends in FSW process of aluminum alloys and aluminum metal matrix composites(Al MMCs).Also,it discusses the effect of welding parameters of the traditional and state-of-the-art developed FSW techniques on the welding quality and strength of aluminum alloys and Al MMCs.Comparison among the techniques and advantages and limitations of each are considered.The review suggests that VFSW is a viable option for welding aluminum joints due to its energy efficiency,economic cost,and versatile modifications that can be employed based on the application.This review also illustrated that significantly less attention has been paid to FSW of Al-MMCs and considerable attention is demanded to produce qualified joint.展开更多
Objective: To investigate the contribution of placental leptin to the serum levels in preeclampsia and the effect of hypoxia on synthesis of placental leptin. Methods: Fifteen preeclamptic women and 20 normotensive pr...Objective: To investigate the contribution of placental leptin to the serum levels in preeclampsia and the effect of hypoxia on synthesis of placental leptin. Methods: Fifteen preeclamptic women and 20 normotensive pregnant women were recruited in present study. Leptin concentrations in peripheral venous blood samples and uterine venous blood samples were measured by radioimmunoassay. Eight cases of normal human term placental villi were cultured either in normaxia （21%O2） or in hypoxia （2%O2） followed by determining leptin in the culture medium by radioimmunoassay. Results: Leptin concentrations were significantly higher in preeclamptic women than in normotensive pregnant women, both in the peripheral vein （[23.29±12.87] μg/L vs [13.87±5.57] μg/L, P<0.01） and uterine vein （[16.44±8.62] μg/L vs [11.21±4.20] μg/L, P<0.05）. Leptin concentrations were significantly higher in the peripheral vein than in uterine vein, both in the preeclamptic （P<0.01） and in normotensive pregnant women （P<0.01）. Concentrations of leptin in the culture medium were significantly increased in hypoxia than in normoxia （P<0.05）. Conclusion: The pathogenesis of preeclampsia may be associated with an increase of maternal serum leptin and placenta leptin, and hypoxia in placenta may be an important factor that results in preeclamptic placenta to produce more leptin. Placenta is not the principal source of the serum leptin in the preeclamptic women or normotensive pregnant women.展开更多
文摘标引深度(depth of indexing)的论题在相当多的著述中涉及,然而,见智见仁、众说纷纭;有的论者对标引系统的评述似乎故意避开了这个概念,有的干脆则认定标引深度易于导致紊乱,好象这个概念并非必不可少。我们认为:在析解文献主题及向受控语言转换的过程中,对文献论题的确认,尽管源于贯串检索系统全过程的各个或隐或显的因素的交互制牵、而变得有点扑朔迷离;
文摘Based on my teaching and working experience in Europe, I have made a comparison between the Chinese and European patients in acupuncture treatment, and hope it is of some significance in acupuncture clinical practice.
文摘This study addresses current status of ESSQ management and integration in steel production organisation. The idea is to benchmark maturity levels with the leading Finnish international companies. The examination has been done in compliance with applied maturity model developed by the target corporation. When examining the benchmarked companies through the ESSQ framework, we found that a similar framework cannot be found in any other company as such; instead, operations are distributed under different organisations. Although many sources criticise system-based development, the results of this study indicate that it is nevertheless an efficient way to develop operations.
基金United Arab Emirates University (UAEU), Al-Ain, UAE, and Sultan Qaboos University (SQU), Muscat, Sultanate of Oman, for providing research support through a collaborative research project (UAEU: 31N270)。
文摘Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.However,fusion welding of aluminum alloys is challenging due to several factors,including the presence of non-heat-treatable alloys,porosity,solidification,and liquation of cracks.Many manufacturers adopt conventional in-air friction stir welding(FSW)to weld metallic alloys and dissimilar materials.Many researchers reported the drawbacks of this traditional in-air FSW technique in welding metallic and polymeric materials in general and aluminum alloys and aluminum matrix composites in specific.A number of FSW techniques were developed recently,such as underwater friction stir welding(UFSW),vibrational friction-stir welding(VFSW),and others,for welding of aluminum alloy joints to overcome the issues of welding using conventional FSW.Therefore,the main objective of this review is to summarize the recent trends in FSW process of aluminum alloys and aluminum metal matrix composites(Al MMCs).Also,it discusses the effect of welding parameters of the traditional and state-of-the-art developed FSW techniques on the welding quality and strength of aluminum alloys and Al MMCs.Comparison among the techniques and advantages and limitations of each are considered.The review suggests that VFSW is a viable option for welding aluminum joints due to its energy efficiency,economic cost,and versatile modifications that can be employed based on the application.This review also illustrated that significantly less attention has been paid to FSW of Al-MMCs and considerable attention is demanded to produce qualified joint.
文摘Objective: To investigate the contribution of placental leptin to the serum levels in preeclampsia and the effect of hypoxia on synthesis of placental leptin. Methods: Fifteen preeclamptic women and 20 normotensive pregnant women were recruited in present study. Leptin concentrations in peripheral venous blood samples and uterine venous blood samples were measured by radioimmunoassay. Eight cases of normal human term placental villi were cultured either in normaxia （21%O2） or in hypoxia （2%O2） followed by determining leptin in the culture medium by radioimmunoassay. Results: Leptin concentrations were significantly higher in preeclamptic women than in normotensive pregnant women, both in the peripheral vein （[23.29±12.87] μg/L vs [13.87±5.57] μg/L, P<0.01） and uterine vein （[16.44±8.62] μg/L vs [11.21±4.20] μg/L, P<0.05）. Leptin concentrations were significantly higher in the peripheral vein than in uterine vein, both in the preeclamptic （P<0.01） and in normotensive pregnant women （P<0.01）. Concentrations of leptin in the culture medium were significantly increased in hypoxia than in normoxia （P<0.05）. Conclusion: The pathogenesis of preeclampsia may be associated with an increase of maternal serum leptin and placenta leptin, and hypoxia in placenta may be an important factor that results in preeclamptic placenta to produce more leptin. Placenta is not the principal source of the serum leptin in the preeclamptic women or normotensive pregnant women.
