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409篇 您的检索式:作者名="Zhang Yongjun"
    题名 作者 年代 出处 被引量
1Production of bioactive ginsenoside compound K in metabolically engineered yeast显示文摘Xing Yan Yun Fan Wei Wei Pingping Wang Qunfang Liu Yongjun Wei Lei Zhang Guoping Zhao Jianmin Yue Zhihua Zhou 2014Cell Research2014,24,6:81
2The Tartary Buckwheat Genome Provides Insights into Rutin Biosynthesis and Abiotic Stress Tolerance显示文摘Zhang, Lijun Li, Xiuxiu Ma, Bin Gao, Qiang Du, Huilong Han, Yuanhuai Li, Yan Cao, Yinghao Qi, Ming Zhu, Yaxin Lu, Hongwei Ma, Mingchuan Liu, Longlong Zhou, Jianping Nan, Chenghu Qin, Yongjun Wang, Jun Cui, Lin Liu, Huimin Liang, Chengzhi Qiao, Zhijun 2017Molecular Plant2017,10,9:53
3The Chinese Stroke Association scientific statement:intravenous thrombolysis in acute ischaemic stroke显示文摘The most effective medical treatment for acute ischaemic stroke(AIS)is to offer intravenous thrombolysis during the ultra-early period of time after the onset.Even based on the Consensus of Chinese Experts on Intravenous Thrombolysis for AIS in 2012 and 2014 Chinese Guidelines on the Diagnosis and Treatment of AIS,the rate of thrombolysis for AIS in China remained around 2.4%,and the rate of intravenous tissue plasminogen activator usage was only about 1.6%in real world.The indication of thrombolysis for AIS has been expanded,and contraindications have been reduced with recently published studies.In order to facilitate the standardisation of treating AIS,improve the rate of thrombolysis and benefit patients who had a stroke,Chinese Stroke Association has organised and developed this scientific statement.Qiang Dong Yi Dong Liping Liu Anding Xu Yusheng Zhang Huaguang Zheng Yongjun Wang 2017Stroke & Vascular Neurology2017,2,3:56
4Chinese Stroke Center Alliance:a national effort to improve healthcare quality for acute stroke and transient ischaemic attack:rationale,design and preliminary findings显示文摘Background In June 2015,the Chinese Stroke Association(CSA)initiated the Chinese Stroke Center Alliance(CSCA)to establish the national hospital-based stroke care quality assessment and improvement platform.This article outlines its objectives,operational structure,patient population,quality improvement(QI)intervention tools,data elements,data collection methodology and current patient and hospital data.Methods The CSCA is a national,hospital-based,multicentre,voluntary,multifaceted intervention and continuous QI initiative.This multifaceted intervention includes stroke centre development,written care protocols,workshops and a monitoring/feedback system of evidencebased performance measures.The data coordinating centre of the CSCA resides at the China National Clinical Research Center for Neurological Diseases,Beijing Tiantan Hospital.results As of July 2017,1576 hospitals in China have contributed detailed clinical information to serve as a benchmark for the stroke care quality of 433264 patients with acute stroke/transient ischaemic attacks(TIA),including 352572(81.38%)acute ischaemic stroke,30362(7.01%)TIA,42080(9.71%)spontaneous intracranial haemorrhage,5505(1.27%)subarachnoid haemorrhage and 2745(0.63%)not specified stroke.Conclusion The CSCA programme is designed to establish a continuous national stroke registry and help healthcare providers develop stroke centres and treat patients in a consistent manner in accordance with accepted national guidelines and,ultimately,improve patient outcomes.It supports the CSA mission to reduce stroke burden in China.Yongjun Wang Zixiao Li Yilong Wang Xingquan Zhao Liping Liu Xin Yang Caiyun Wang Hongqiu Gu Fuying Zhang Chunjuan Wang Ying Xian David Z Wang Qiang Dong Anding Xu Jizong Zhao Chinese Stroke Center Alliance investigators 2018Stroke & Vascular Neurology2018,3,4:38
5Coordinated optimal dispatch and market equilibrium of integrated electric power and natural gas networks with P2G embedded显示文摘As power to gas(P2 G) technology gradually matures, the coupling between electricity networks and natural gas networks should ideally evolve synergistically.With the intent of characterizing market behaviors of integrated electric power and natural gas networks(IPGNs)with P2 G facilities, this paper establishes a steady-state model of P2 G and constructs optimal dispatch models of an electricity network and a natural gas network separately. In addition, a concept of slack energy flow(SEF) is proposed as a tool for coordinated optimal dispatch between the two networks. To study how the market pricing mechanism affects coordinated optimal dispatch in an IPGN, a market equilibrium-solving model for an IPGN is constructed according to game theory, with a solution based on the Nikaido-Isoda function. Case studies are conducted on a joint model that combines the modified IEEE 118-node electricity network and the Belgian 20-node gas network.The results show that if the game between an electric power company and a natural gas company reaches market equilibrium, not only can both companies maximize their profits, but also the coordinated operation of the coupling units, i.e., gas turbines and P2 G facilities, will contribute more to renewable energy utilization and carbon emission reduction.Zexing CHEN Yongjun ZHANG Tianyao JI Zexiang CAI Licheng LI Zhiheng XU 2018Journal of Modern Power Systems and Clean Energy2018,6,3:37
6Stenting for symptomatic intracranial arterial stenosis in China:1-year outcome of a multicentre registry study显示文摘background and purpose A multicentre prospective registry study of individually tailored stenting for a patient with symptomatic intracranial atherosclerotic stenosis(ICAS)combined with poor collaterals in China showed that the short-term safety and efficacy of stenting was acceptable.However,it remained uncertain whether the low event rate could be of a long term.We reported the 1-year outcome of this registry study to evaluate the long-term efficacy of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Methods Patients with symptomatic ICAS caused by 70%-99% stenosis located at the intracranial internal carotid,middle cerebral,intracranial vertebral or basilar arteries combined with poor collaterals were enrolled.Balloon-mounted stent or balloon plus self-expanding stent were selected based on the ease of vascular access and lesion morphology determined by the operators.The primary outcome was the rate of 30-day stroke,transient ischaemic attack and death,and 12-month ischaemic stroke within the same vascular territory,haemorrhagic stroke and vascular death after stenting.results From September 2013 to January 2015,300 patients(ages 58.3±9.78 years)were recruited.Among them,159 patients were treated with balloon-mounted stent and 141 with balloon plus self-expanding stent.During the 1-year follow-up,25 patients had a primary end point event.The probability of primary outcome at 1 year was 8.1%(95% CI 5.3% to 11.7%).In 76 patients with digital subtraction angiography follow-up,27.6%(21/76)had re-stenosis≥50% and 18.4%(14/76)had re-stenosis≥70%.No baseline characteristic was associated with the primary outcome.Conclusion The event rate remains low over 1 year of individually tailored stenting for patients with severe symptomatic ICAS combined with poor collaterals.Further randomised trial of comparing individually tailored stenting with best medical therapy is needed.Ning Ma Yong Zhang Jie Shuai Changchun Jiang Qiyi Zhu Kangning Chen Li Liu Baomin Li Xiangqun Shi Lianbo Gao Yajie Liu Feng Wang Yongli Li Tieyan Liu Hongbo Zheng Dapeng Mo Feng Gao Yilong Wang Yongjun Wang Lei Feng Zhongrong Miao 2018Stroke & Vascular Neurology2018,3,3:29
7Recent temperature increase recorded in an ice core in the source region of Yangtze River显示文摘Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ^(18)O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ^(18)O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the begin-ning of the 21st century. The warming rate recorded in the ice core with 0.5℃/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1℃/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warm-ing and a more sensitive response to global warming in the high elevation region.KANG ShiChang ZHANG YongJun QIN DaHe REN JiaWen ZHANG QiangGong Bjorn GRIGHOLM Paul A. MAYEWSKI 2007Chinese Science Bulletin2007,52,6:27
8SHRIMP U-Pb Zircon Geochronology of the Xiaotongguanshan and Shatanjiao Intrusions and Its Petrological Implications in the Tongling Area, Anhui显示文摘This paper determines the crystallization ages of the Xiaotongguanshan quartz monzodiorite and Shatanjiao quartz monzonite porphyry from the Tongling area using the SHRIMP zircon U-Pb method. The crystallization age of the former is 142.8±1.8 Ma; that of the latter is 151.8±2.6 Ma. These data indicate that they were formed during the Late Jurassic (142.8 to 151.8 Ma). Zoned magma chamber was formed because of double diffusive convection. Therefore, the intrusive sequence of magma is generally from quartz monzonite through quartz monzodiorite to pyroxene monzodiorite, i.e. an inverted sequence.DI Yongjun WU Ganguo ZHANG Da SONG Biao ZANG Wenshuan ZHANG Zhongyi LI Jinwen 2005Acta Geologica Sinica(English Edition)2005,79,6:22
9Review and prospect of transgenic rice research显示文摘Rice is one of the most important crops as the staple food for more than half of the world's population. Rice improvement has achieved remarkable success in the past half-century, with the yield doubled in most parts of the world and even tripled in certain regions, which has contributed greatly to food security globally. Rapid population growth and economic development pose a constantly increased food requirement. However, rice yield has been hovering in the past decade, which is mainly caused by the absence of novel breeding technologies, reduction of genetic diversity of rice cultivars, and serious yield loss due to increasingly severe occurrences of insects, diseases, and abiotic stresses. To address these challenges, Chinese scientists proposed a novel rice breeding goal of developing Green Super Rice to improve rice varieties and realize the sustainable development of agriculture, by focusing on the following 5 classes of traits: insect and disease resistance, drought-tolerance, nutrient-use efficiency, quality and yield potential. As a modern breeding approach, transgenic strategy will play an important role in realizing the goal of Green Super Rice. Presently, many transgenic studies of rice have been conducted, and most of target traits are consistent with the goal of Green Super Rice. In this paper, we firstly review technical advances of rice transformation, and then outline the main progress in transgenic rice research with respect to the most important traits: insect and disease-resistance, drought-tolerance, nutrient-use efficiency, quality, yield potential and herbicide-tolerance. The prospects of developing transgenic rice are also discussed.CHEN Hao LIN YongJun ZHANG QiFa 2009Chinese Science Bulletin2009,54,22:22
10Identification and functional annotation of novel microRNAs in the proximal sciatic nerve after sciatic nerve transection显示文摘The peripheral nervous system is able to regenerate after injury, and regeneration is associated with the expression of many genes and proteins. MicroRNAs are evolutionarily conserved, small, non-coding RNA molecules that regulate gene expression at the level of translation. In this paper, we focus on the identification and functional annotation of novel microRNAs in the proximal sciatic nerve after rat sciatic nerve transection. Using Solexa sequencing, computational analysis, and quantitative reverse transcription PCR verification, we identified 98 novel microRNAs expressed on days 0, 1, 4, 7, and 14 after nerve transection. Furthermore, we predicted the target genes of these microRNAs and analyzed the biological processes in which they were involved. The identified biological processes were consistent with the known time-frame of peripheral nerve injury and repair. Our data provide an important resource for further study of the role and regulation of microRNAs in peripheral nerve injury and regeneration.LI ShiYing YU Bin WANG YongJun YAO DengBing ZHANG ZhanHu GU XiaoSong 2011Science China(Life Sciences)2011,54,9:16
11Autophagy in Atherosclerosis: A Phenomenon Found in Human Carotid Atherosclerotic Plaques显示文摘Huihui Liu Yongjun Gag Tong Tong Jijun Shi Yanlin Zhang Yaping Yang Chunfeng Liu 2015Chinese Medical Journal2015,,1:16
12Groundwater quality and land use change in a typical karst agricultural region:a case study of Xiaojiang watershed,Yunnan显示文摘Taking the typical karst agricultural region, Xiaojiang watershed in Luxi of Yunnan Province as a research unit, utilizing the groundwater quality data in 1982 and 2004, the aerial photos in 1982 and TM images in 2004, supported by the GIS, we probe into the law and the reason of its space-time change of the groundwater quality over the past 22 years in the paper. The results show: (1) There were obvious temporal and spatial changes of groundwater quality during the past 22 years. (2) Concentrations of NH +4, 2? SO 4, NO 3?, NO 2?, Cl ?and the pH value, total hardness, total alkalinity increased significantly, in which + NH 4, NO 3?, and NO ?2of groundwater exceeded the drinking water standards as a result of non-point pollution caused by the expansion of cultivated land and mass use of the fertilizer and pesticide. (3) Oppositely, Ca2+ and HCO 3?showed an obvious decline trend due to forest reduction and degradation and stony desertification. Meantime, there was a dynamic relation between the groundwater quality change and the land use change.JIANG Yongjun YUAN Daoxian XIE Shiyou LI Linli ZHANG Gui HE Raosheng 2006Journal of Geographical Sciences2006,16,4:14
13Identification and standardization of maneuvers based upon operational flight data显示文摘To find a way of loads analysis from operational flight data for advanced aircraft,maneuver identification and standardization jobs are conducted in this paper. For thousands of sorties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneuvers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recognition theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as averaging and smoothing, the idealization standard time history of each maneuver type is established.Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program(IATP).Wang Yongjun Dong Jiang Liu Xiaodong Zhang Lixin 2015Chinese Journal of Aeronautics2015,28,1:13
14Research Progress on Heat Stress of Rice at Flowering Stage显示文摘Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.WANG Yaliang WANG Lei ZHOU Jianxia HU Shengbo CHEN Huizhe XIANG Jing ZHANG Yikai ZENG Yongjun SHI Qinghua ZHU Defeng ZHANG Yuping 2019Rice science2019,26,1:13
15Hot deformation behavior of Mg-7.22Gd-4.84Y-1.26Nd-0.58Zr magnesium alloy显示文摘The behavior evolvement of Mg-7.22Gd-4.84Y-1.26Nd-0.58Zr(GWN751K) magnesium alloy during the hot deformation process was discussed.The flow stress behavior of the magnesium alloy over the strain rate range of 0.002 to 2.000 s-1 and in the temperature range of 623 to 773 K was studied on a Gleeble-1500D hot simulator under the maximum deformation degree of 60%.The experimental results showed that the relationship between stress and strain was obviously affected by strain rate and deformation temperature.The flow stress of GWN751K magnesium alloy during high temperature deformation could be represented by the Zener-Hollomon parameter in the hyperbolic Arrhenius-type equation.The stress exponent n and deformation activation energy Q were evaluated by linear regression analysis.The stress exponent n was fitted to be 3.16.The hot deformation activation energy of the alloy during hot deformation was 230.03 kJ/mol.The microstructures of hot deformation were also influenced by strain rate and compression temperature strongly.It was found that the alloy could be extruded at 723 K with the mechanical properties of σ0.2 = 260 MPa,σb = 320 MPa,and δ = 18%.ZHANG Kui MA Minglong LI Xinggang LI Yongjun LIANG Lichao BING Mengfen 2011Rare Metals2011,30,1:13
16Factors Associated with Thrombolysis Outcome in Ischemic Stroke Patients with Atrial Fibrillation显示文摘The outcome of early intravenous thrombolysis for ischemic stroke in patients with atrial fibrillation(AF)is worse than that without thrombosis. How to increase the efficacy of intravenous thrombolysis for AF-related ischemic stroke remains largely unknown. In this study, we investigated factors that influence the effect of intravenous thrombolysis in these patients. Our results showed that thrombolysis was independently associated with a favorable outcome(P \ 0.001) and did not influence the mortality of AF-related ischemic stroke, although it increased the risk of hemorrhage within 24 h after treatment. Risk factors for a poor outcome at admission were:heart failure(P = 0.045); high systolic pressure(P = 0.039); high blood glucose(P = 0.030); and a high National Institutes of Health Stroke Scale(NIHSS) score(P \ 0.001). Moreover, high systolic pressure at admission(P = 0.007), high blood glucose(P = 0.027), and a high NIHSS score(P \ 0.001) were independent risk factors for mortality at 3 months. Besides thrombolysis, a high NIHSS score(P = 0.006) and warfarin taken within 48 h before stroke onset(P = 0.032) were also independent risk factors for symptomatic hemorrhage within 24 h after treatment. Ischemic stroke patients with AF benefited from intravenous thrombolysis with recombinant tissue plasminogen activator within 4.5 h after stroke.Qiuyun Zhao Xiaobo Li Wanli Dong Min Ye Yongjun Cao Meijuan Zhang Qiantao Cheng Junshan Zhou Guofang Chen Ming Yu Shanshan Hong Xiue Wei Bei Wang Guiyun Cui Peng Zhang Hong Ding Rongzhen Xu Yan Chen Yun Xu 2016Neuroscience Bulletin2016,32,2:13
17The calcium-dependent kinase OsCPK24 functions in cold stress responses in rice显示文摘Calcium-dependent protein kinases(CPKs)are serine/threonine protein kinases that function in plant stress responses. Although CPKs are recognized as key messengers in signal transduction, the specific roles of CPKs and the molecular mechanisms underlying their activity remain largely unknown. Here, we characterized the function of Os CPK_(24), a cytosol-localized calciumdependent protein kinase in rice. Os CPK_(24) was universally and highly expressed in rice plants and was induced by cold treatment. Whereas Os CPK_(24) knockdown plants exhibited increased sensitivity to cold compared to wild type(WT), Os CPK_(24)-overexpressing plants exhibited increased cold tolerance. Plants overexpressing Os CPK_(24) exhibited increased accumulation of proline(an osmoprotectant) and glutathione(an antioxidant) and maintained a higher GSH/GSSG(reduced glutathione to oxidized glutathione) ratio during cold stress compared to WT. In addition to these effects in response to cold stress, we observed the kinase activity of Os CPK_(24) varied under different calcium concentrations. Further,Os CPK_(24) phosphorylated Os Grx_(10), a glutathionedependent thioltransferase, at rates modulated by changes in calcium concentration. Together, our results support the hypothesis that Os CPK_(24) functions as a positive regulator of cold stress tolerance in rice, a process mediated by calcium signaling and involving phosphorylation and the inhibition of Os Grx_(10) to sustain higher glutathione levels.Yu Liu Chunjue Xu Yanfen Zhu Lina Zhang Taiyu Chen Fei Zhou Hao Chen Yongjun Lin 2018Journal of Integrative Plant Biology2018,60,2:12
18The Early Jurassic magmatism in northern Guangdong Province, southeastern China: Constraints from SHRIMP zircon U-Pb dating of Xialan complex显示文摘This paper reports SHRIMP zircon U-Pb ages of 196±2 Ma for granite, and 195±1 Ma for gabbro from the Xialan complex in the Meizhou area, northern Guangdong Province. These results shed new light on the calm stage of magmatic activity in southeastern China during 200-180 Ma, and revealed that the back-arc extension induced by the subduction of the western Pacific plate may have begun at 195 Ma at least. Field observation on the fresh outcrops allows us to recognize some features formed by magma mixing. A part of the gabbro has a fine-grained rim of 20-30 cm at the margin, and thins gradually to-ward the granite; numerous dark fine-grained to microcrystalline dioritic enclaves developed in the granite. These enclaves vary in shape and size, dark minerals concentrated at the margin of enclaves, and the contact between enclaves and host rock is either obvious or obscure, or gradational. In addi-tion, needle-shaped apatites are included in the enclaves. The REE patterns of gabbros, as well as the trace element patterns, are generally consistent with those of granitic rocks. The above characters further suggest that in the Early Jurassic the injection of basic magma had melted deep continental crust and produced acidic magma, and the Xialan complex was produced by the mixing of them.YU XinQi DI YongJun WU GanGuo ZHANG Da ZHENG Yong DAI YanPei 2009Science China Earth Sciences2009,52,4:12
19Oridonin inhibits BxPC-3 cell growth through cell apoptosis显示文摘Oridonin,从繁体中文植物 Rabdosia rubescens 提取的 ent-kaurene diterpenoid,有多重生物、药品的功能并且临床上被使用许多年了。当 oridonin 的 antitumor 功能被证据的众多的线支持了时,它的 anticancer 机制很好没被记录。在这研究,胰腺的癌症房间线 BxPC-3 被用作一个模型通过在房间生存能力上检验它的效果调查 oridonin 的可能的 anticancer 机制。结果证明 oridonin 在一个时间依赖者和剂量依赖者举止影响了房间生存能力。在到不同 oridonin 集中的暴露以后,生长率和 BxPC-3 房间的房间周期拘捕显著地与未经治疗的房间相比被减少,建议它增长抑制上的效果。由西方的污点分析的详细发信号的小径分析表明低剂量的 oridonin 治疗由起来调整的 p53 和下面调整的 cyclin 依赖的 kinase 禁止了 BxPC-3 房间增长 1 (CDK1 ) ,它在 G2/M 阶段导致了房间周期拘捕。高剂量的 oridonin 不仅在 G2/M 阶段逮捕了 BxPC-3 房间而且在 S 阶段导致了房间累积,大概,通过 H2AX,起来规定和 DNA 损坏。另外,我们的结果证明房间 subpopulation 在 oridonin 治疗以后与 propidium 碘化物被染色。蛋白质 quantification 显示出 poly 劈开那(自动数据处理核糖) 聚合酶(PARP ) 表示在一个高剂量的 oridonin 处理以后被增加,特别在长期的暴露以后。在表情也是的房间, apoptosis 开始者 caspase-3 和 caspase-7 显著地增加了的 BxPC-3 由撤销 PARP 的增加的水平伴随了,建议调停 caspase 的 apoptosis 贡献了房间死亡。Bin Xu Wen Shen Xing Liu Ting Zhang Jun Ren Yongjun Fan Jian Xu 2015Acta Biochimica et Biophysica Sinica2015,47,3:11
20Microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states显示文摘The microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states were studied.The results reveal that island compounds at the grain boundaries of the as-cast alloys mainly were Mg24Y5,Mg41Nd5,and Mg5Gd phases.After homogenization at 808 K for 24 h,the distribution of the island compounds became discrete and Mg5Gd phases mostly decomposed and dissolved.With hot extrusion,the grain size was refined to about 20 μm on average,and both the strength and elongation were greatly improved.After ageing at 523 K for 5 h,the strength of different extruded alloys largely increased but the elongation decreased.With the increase of neodymium content,the strength of the alloys at different states increased.The content of neodymium element had an obvious effect on the elongation of the designed alloys.In the designed alloys,the Mg-5Y-5Gd-2.2Nd-0.5Zr alloy exhibited the best combination properties and its ultimate tensile strength,yield strength,and elongation could reach 380 MPa,285 MPa,and 9.0%,respectively.LI Yongjun ZHANG Kui ZHANG Ya LI Xinggang MA Minglong 2010Rare Metals2010,29,3:11
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