期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
双峰基面织构对Mg-2.6Nd-0.55Zn-0.5Zr合金弯曲应力及显微组织演变的影响
1
作者 张文丛 刘宇轩 +4 位作者 马俊飞 王文珂 陈文振 刘欣彤 杨建雷 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2023年第3期714-727,共14页
沿Mg-2.6Nd-0.55Zn-0.5Zr板材挤压方向(ED)和横向(TD)分别切取试样,研究双峰基面织构对其弯曲应力及显微组织演变的影响。结果显示,具有弱基面织构的ED试样比TD试样的弯曲应力低很多。这种各向异性是不同织构状态对变形机制及显微组织... 沿Mg-2.6Nd-0.55Zn-0.5Zr板材挤压方向(ED)和横向(TD)分别切取试样,研究双峰基面织构对其弯曲应力及显微组织演变的影响。结果显示,具有弱基面织构的ED试样比TD试样的弯曲应力低很多。这种各向异性是不同织构状态对变形机制及显微组织演变的作用所导致的。对于具有弱基面织构的ED试样,其主要的变形机制是基面滑移:内侧区域存在少量的{10■2}拉伸孪生,而外侧区域则是基面滑移和柱面滑移。相比之下,具有强基面织构的TD试样在内侧区域激活更多的{10■2}拉伸孪生,在外侧区域激活更多的柱面滑移。{10■2}拉伸孪生的激活一方面促使<0002>//压缩方向类型的织构增加,使内侧区域的织构角度限制在±30°范围内,另一方面减少高位错密度和低角度晶界的出现几率。{10■2}拉伸孪生的大量激活使TD试样保持高应变硬化能力,是该试样具有较高弯曲应力的根本原因。 展开更多
关键词 Mg-Nd-Zn-Zr合金 织构 拉伸孪生 三点弯曲 弯曲应力 显微组织演变
下载PDF
Relationships between microhardness, microstructure, and grain orientation in laser-welded joints with different welding speeds for Ti6Al4V titanium alloy 被引量:14
2
作者 Zhen-zhen XU Zhi-qiang DONG +2 位作者 Zhao-hui YU wen-ke wang Jian-xun ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1277-1289,共13页
The microhardness curve trend and its relationships with microstructure and misorientation were analyzed to enhance the comprehension of the microstructure and mechanical property of micro-areas in Ti6 Al4 V laser-wel... The microhardness curve trend and its relationships with microstructure and misorientation were analyzed to enhance the comprehension of the microstructure and mechanical property of micro-areas in Ti6 Al4 V laser-welded joints with different welding speeds. The microhardness measured on the fusion line(H_m) is the highest from the weld center to the base metal. H_m increases with increasing weld width in a welded joint and increasing degree of the non-uniformity in all studied welded joints. The microhardness decreases from the weld metal to the base metal with decreasing amount of martensite α’ and increasing amount of original α phase. When the microstructure is mainly composed of martensite α’, the microhardness changes with the cooling rate, grain size of the martensite, and peak values of the fraction of misorientation angle of the martensite in a wide weld metal zone or weld center at different welding speeds, whereas the difference is small in a narrow weld metal zone. 展开更多
关键词 MICROHARDNESS MICROSTRUCTURE misorientation angle NON-UNIFORMITY welding speed
下载PDF
Analysis of risk factors for central venous port failure in cancer patients 被引量:12
3
作者 Ching-Chuan Hsieh Hsu-Huei Weng +4 位作者 Wen-Shih Huang wen-ke wang Chiung-Lun Kao Ming-Shian Lu Chia-Siu wang 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第37期4709-4714,共6页
AIM: To analyze the risk factors for central port failure in cancer patients administered chemotherapy, using univariate and multivariate analyses. METHODS: A total of 1348 totally implantable venous access devices (T... AIM: To analyze the risk factors for central port failure in cancer patients administered chemotherapy, using univariate and multivariate analyses. METHODS: A total of 1348 totally implantable venous access devices (TIVADs) were implanted into 1280 cancer patients in this cohort study. A Cox proportional hazard model was applied to analyze risk factors for failure of TIVADs. Log-rank test was used to compare actuarial survival rates. Infection, thrombosis, and surgical complication rates (χ2 test or Fisher's exact test) were compared in relation to the risk factors. RESULTS: Increasing age, male gender and openended catheter use were signifi cant risk factors reducing survival of TIVADs as determined by univariate and multivariate analyses. Hematogenous malignancy decreased the survival time of TIVADs; this reduction was not statistically signifi cant by univariate analysis [hazard ratio (HR) = 1.336, 95% CI: 0.966-1.849, P = 0.080)]. However, it became a signifi cant risk factor by multivariate analysis (HR = 1.499, 95% CI: 1.079-2.083, P = 0.016) when correlated with variables of age, sex and catheter type. Close-ended (Groshong) catheters had a lower thrombosis rate than open-ended catheters (2.5% vs 5%, P = 0.015). Hematogenous malignancy had higher infection rates than solid malignancy (10.5% vs 2.5%, P < 0.001). CONCLUSION: Increasing age, male gender, openended catheters and hematogenous malignancy were risk factors for TIVAD failure. Close-ended catheters had lower thrombosis rates and hematogenous malignancy had higher infection rates. 展开更多
关键词 Central venous port CHEMOTHERAPY Risk factor Cancer patient Multivariate analysis
下载PDF
Effects of heavy metal pollution on farmland soils and crops:A case study of the Xiaoqinling Gold Belt,China 被引量:27
4
作者 Rui-ping Liu You-ning Xu +2 位作者 Jiang-hua Zhang wen-ke wang Rafaey M Elwardany 《China Geology》 2020年第3期402-410,共9页
This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to t... This paper focuses on the heavy metal enrichment and heavy metal pollution degree associated with mining activities in some crops and the soils of different parent materials in the Xiaoqinling Gold Belt.According to the geochemical analysis results of the soils observed in the gold belt,the soils are most highly enriched in Pb,followed by Cr,Cu,and Zn.Furthermore,they are relatively poor in Hg,Cd,and As.It is also shown that the heavy metals in all kinds of soils have the same geochemical characteristics in the gold belt.As for the crops(such as corn and wheat)in the gold belt,Zn and Cu are the most abundant elements,followed by Pb and Cr.Meanwhile,Hg,Cd,and As were found to have relatively low concentrations in the crops.The heavy metals in wheat and corn have the same geochemical characteristics in the gold belt in general.Compared to the aeolian loess soils and the crops therein,heavy metals are more enriched in diluvial and alluvial soils and the crops therein.As shown by relevant studies,the Hg,Pb,Cd,Cu,and Zn pollution are mainly caused by mining activities.Corn and wheat in the gold belt have a high tendency of risk exposure to heavy metal pollution since they are mostly affected by mining activities and feature high background values of heavy metal concentrations.Furthermore,wheat is more liable to be enriched in heavy metals than corn is grown in all types of soils.The Hg pollution in soils leads to Hg accumulation,increasing the risk of Hg uptake in crops,and further affecting human health.This study will provide a scientific basis for the control and management of heavy metals in farmland soils of mining areas. 展开更多
关键词 Heavy metal pollution CROPS FARMLAND Environmental investigation engineering of soil Xiaoqinling Gold Belt China
下载PDF
Evolution of microstructure and mechanical properties of ZK60 magnesium alloy processed by asymmetric lowered-temperature rolling 被引量:4
5
作者 Wen-cong ZHANG Xin-tong LIU +4 位作者 Jun-fei MA wen-ke wang Wen-zhen CHEN Yu-xuan LIU Jian-lei YANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第9期2877-2888,共12页
Asymmetric lowered-temperature rolling was applied to the fabrication of fine-grained ZK60 magnesium alloy sheet with weak basal texture along the rolling direction(RD).The results showed that multi-pass lowered-tempe... Asymmetric lowered-temperature rolling was applied to the fabrication of fine-grained ZK60 magnesium alloy sheet with weak basal texture along the rolling direction(RD).The results showed that multi-pass lowered-temperature rolling could significantly improve the microstructure homogeneity and refine the grain size.Meanwhile,a fiber texture along the transverse direction(TD)gradually developed during rolling process.Importantly,the shear deformation along the RD made the c-axis of basal plane rotate to the RD,weakening the basal texture along this direction.Influenced by such microstructure variation,the yield strength along the TD continuously increased due to the successive grain refinement and the increased activation of prismatic slips,whereas the uniform elongation decreased owing to the decline of strain hardening ability.In contrast,the continuous weakening of basal texture along the RD increased the activation of soft basal slips,greatly offsetting the strengthening effect contributed by grain refinement and thereby causing the slight decrease of yield strength. 展开更多
关键词 ROLLING asymmetric rolling grain size TEXTURE yield stress
下载PDF
Thermodynamic transport mechanism of water freezing-thawing in the vadose zone in the alpine meadow of the Tibet Plateau 被引量:1
6
作者 Gang Qiao Feng-dan Yu +2 位作者 wen-ke wang Jun Zhang Hua-qing Chen 《Journal of Groundwater Science and Engineering》 2022年第3期302-310,共9页
High altitude,cold and dry climate,strong solar radiation,and high evapotranspiration intensity have created an extremely fragile ecological and geological environment on the Tibet Plateau.Since the heat in the vadose... High altitude,cold and dry climate,strong solar radiation,and high evapotranspiration intensity have created an extremely fragile ecological and geological environment on the Tibet Plateau.Since the heat in the vadose zone is primarily generated by the external solar radiation energy,and evapotranspiration is contingent on the consumption of vadose heat,the intensity of evapotranspiration is associated with the intensity of solar radiation and the heat budget in the vadose zone.However,the spatial and temporal variation of heat budget and thermodynamic transfer process of the vadose zone in the frigid region are not clear,which hinders the revelation of the dynamic mechanism of evapotranspiration in the vadose zone in the frigid region.With the moisture content of the vadose zone in the alpine regions being the research object,the paper conducts in-situ geothermal observation tests,takes meteorological characteristics into consideration,and adopts the method of geothermal gradient and numerical computation to analyse the temporal and spatial variation rule of heat budget and thermodynamic transmission process of the vadose zone in the high and cold regions.The results show there is a positive correlation between air temperature,ground temperature,and water content of the vadose zone in both thawing and freezing periods.According to the change law of geothermal gradient,the thermodynamic transfer process of the vadose zone has four stages:slow exothermic heating,fast endothermic melting,slow endothermic cooling,and fast exothermic freezing.From the surface down,the moisture freezing rate of the vadose zone is slightly higher than the melting rate.This is of great significance for understanding the evapotranspiration dynamic process of the vadose zone and protecting and rebuilding the ecological and geological environment in the high and cold regions. 展开更多
关键词 Freeze-thaw action THERMODYNAMIC EVAPOTRANSPIRATION Moisture in the vadose zone Tibet plateau
下载PDF
冠状动脉慢性完全闭塞病变微循环临床研究进展 被引量:2
7
作者 杨兴军 杨辉 +2 位作者 郭欣 王文科 李飞 《心脏杂志》 CAS 2019年第4期474-478,共5页
冠脉慢性完全闭塞时,良好的微循环灌注是远端存活心肌生存的必要条件。精细的冠脉血流自身调节机制是保证微循环灌注的重要组分。正确认识自身调节机制以及冠状动脉慢性完全闭塞病变(CTO)微循环功能的变化对临床工作至关重要。本文从微... 冠脉慢性完全闭塞时,良好的微循环灌注是远端存活心肌生存的必要条件。精细的冠脉血流自身调节机制是保证微循环灌注的重要组分。正确认识自身调节机制以及冠状动脉慢性完全闭塞病变(CTO)微循环功能的变化对临床工作至关重要。本文从微循环的自身调节机制及CTO的微循环功能变化方面做一综述。 展开更多
关键词 慢性完全闭塞病变 微循环 临床研究
下载PDF
Design,synthesis and biological evaluation of LpxC inhibitors with novel hydrophilic terminus 被引量:2
8
作者 Shi Ding wen-ke wang +4 位作者 Qiao Cao Wen-Jing Chu Le-Fu Lan Wen-Hao Hu Yu-She Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2015年第6期763-767,共5页
In order to develop novel LpxC inhibitors with good activities and metabolic stability, two series of compounds with hydrophilic terminus have been synthesized and their in vitro antibacterial activities against Esche... In order to develop novel LpxC inhibitors with good activities and metabolic stability, two series of compounds with hydrophilic terminus have been synthesized and their in vitro antibacterial activities against Escherichial coil and Pseudomonas aemginosa were evaluated. Especially, compounds 22b and c exhibited comparable antibacterial activities to CHIR-090 and better metabolic stability than CHIR-090 and LPC-011 in liver microsomes (rat and mouse), which indicated the terminal methylsulfone may be a preferred structure in the design of LpxC inhibitors and worthy of further investigations. 展开更多
关键词 LpxC CHIR-090 Kojic acid derivatives Methylsulfone derivatives Metabolic stability
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部