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高铁开通对城市群发展的非均衡影响——基于广东省样本研究 被引量:1
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作者 岳鹄 叶实 吴美贤 《财经理论研究》 2024年第2期68-79,共12页
本文基于“多中心-外围”城市群理论模型,利用2005—2019年广东省21个地级市数据,考察了高铁开通对城市群发展影响的机制与效果。研究表明:高铁开通显著促进了城市群整体的经济发展,且这种影响在城市群内呈现非均衡表现;机制检验表明,... 本文基于“多中心-外围”城市群理论模型,利用2005—2019年广东省21个地级市数据,考察了高铁开通对城市群发展影响的机制与效果。研究表明:高铁开通显著促进了城市群整体的经济发展,且这种影响在城市群内呈现非均衡表现;机制检验表明,高铁开通可以通过企业和人口转移对城市群资源进行重新配置;高铁对于城市群经济发展的作用受到建成时间的影响,在高铁建成的第二年中心城市产生“聚集效应”并显著促进经济发展,从第三年开始逐步转化为“辐射效应”。基于以上研究结论,本文提出如下政策建议,进一步加快广东省高速铁路建设速度,促进城市群之间互联互通;高铁建设规划要因地制宜,防止外围城市资源过度流失;同时,外围城市也应做好承接准备,充分利用中心城市的“辐射效应”。 展开更多
关键词 高铁 城市群 “多中心-外围” 双重差分模型
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Recent progress in the development of dielectric elastomer materials and their multilayer actuators
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作者 Shengchao JIANG Junbo PENG +2 位作者 Lvting WANG Hanzhi MA ye shi 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2024年第3期183-205,共23页
Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible proc... Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements. 展开更多
关键词 Dielectric elastomer actuator(DEA) Dielectric elastomer(DE) Material svnthesis Multilaver stacking method
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甘肃河西地区玉米制种基地晚熟品种高活力种子生产关键技术研究
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作者 安贵 常红飞 +2 位作者 叶石 韩青成 宋文亮 《中国种业》 2023年第3期44-47,51,共5页
随着云、贵、川等西南区域玉米种植面积的大幅增加,西南市场对高产、优质、多抗晚熟玉米品种的需求量逐年增加,因此种子生产企业逐年将西南热带血缘的晚熟玉米种子生产基地由云南、四川区域制种低产区逐步向西北的甘肃、新疆基地转移,... 随着云、贵、川等西南区域玉米种植面积的大幅增加,西南市场对高产、优质、多抗晚熟玉米品种的需求量逐年增加,因此种子生产企业逐年将西南热带血缘的晚熟玉米种子生产基地由云南、四川区域制种低产区逐步向西北的甘肃、新疆基地转移,以实现低成本、高产出,生产能够满足市场需求的高质量种子。而在西北区域种子生产过程中时常存在种子芽率偏低、合格种子数量无法满足市场需求的问题,主要是西北区域晚熟品种灌浆不能完熟与后期霜冻影响种子芽率,导致种子质量不合格。如何保证种子质量,尤其是芽率达标,在多年西北区域制种基地生产过程中,探索总结出西南晚熟玉米品种在西北基地生产、且能够有效保证种子质量的切实可行的生产栽培技术与管理措施,给西北基地承接西南晚熟玉米种子生产提供强有力的技术支撑。 展开更多
关键词 晚熟品种 种子活力 研究
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低醇梨酒发酵工艺优化 被引量:5
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作者 扈钦淋 叶师 +1 位作者 杨春 高文庚 《食品研究与开发》 CAS 北大核心 2021年第6期70-75,共6页
以王过酥梨为原料,采用梨汁发酵生产低醇度梨酒。试验通过单因素和正交试验确定低醇梨酒发酵的最佳工艺条件。结果表明,控制梨汁初始糖度为17%、初始pH值为4.7、偏重亚硫酸钾添加量为160 mg/L、酵母接种量为1.15%,采用17℃发酵4 d,可得... 以王过酥梨为原料,采用梨汁发酵生产低醇度梨酒。试验通过单因素和正交试验确定低醇梨酒发酵的最佳工艺条件。结果表明,控制梨汁初始糖度为17%、初始pH值为4.7、偏重亚硫酸钾添加量为160 mg/L、酵母接种量为1.15%,采用17℃发酵4 d,可得酒度4%vol左右的甜型酒。产品色泽微黄、有光泽度、酸甜适口、香气协调。 展开更多
关键词 酥梨 果酒 低醇度 发酵工艺 优化
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Comparison of Clinical Effects of Au-Pt Based and Ni-Cr Based Porcelain Crowns 被引量:3
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作者 Li-chun Wu ye shi Teng Ma 《Chinese Medical Sciences Journal》 CAS CSCD 2012年第3期167-170,共4页
Objective To compare the long-term clinical effects of two kinds of crowns and bridges made of porcelain fused to Au-Pt alloy and Ni-Cr alloy. Methods A total of 131 teeth (64 patients) were rehabilitated using porcel... Objective To compare the long-term clinical effects of two kinds of crowns and bridges made of porcelain fused to Au-Pt alloy and Ni-Cr alloy. Methods A total of 131 teeth (64 patients) were rehabilitated using porcelain-fused-to-metal crowns, among which 59 were rehabilitated with Au-Pt alloy metal ceramic crown and 72 with Ni-Cr alloy metal ceramic crown. The porcelain fracture, shade, marginal adaptation, gingival discoloration, and gingival status after finishing restoration and 36 months of follow-up were evaluated. Results After 36 months of restoration, porcelain fused to Au-Pt alloy crown showed better clinical effects than porcelain fused to Ni-Cr alloy crown in shade, marginal adaptation, gingival discoloration, as well as gingival status (all P<0.05). Conclusion The Au-Pt alloy ceramic crown is superior to Ni-Cr alloy ceramic crown in long-term clinical effects. 展开更多
关键词 镍铬合金 临床效果 烤瓷冠 结构 牙龈 金属 适合性 修复
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轨道交通桥梁检测技术发展趋势探讨 被引量:2
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作者 郭扬艳 叶诗 韦强 《现代城市轨道交通》 2019年第3期68-70,共3页
随着我国轨道交通桥梁事业的发展,铁路桥梁数量不断刷新世界纪录,但同时部分桥梁也进入修护养护阶段。为了更好地检测桥梁病害情况,在总结轨道交通桥梁检测技术现状的基础上,介绍国内外先进的检测技术,指出现有桥梁检测存在的问题,针对... 随着我国轨道交通桥梁事业的发展,铁路桥梁数量不断刷新世界纪录,但同时部分桥梁也进入修护养护阶段。为了更好地检测桥梁病害情况,在总结轨道交通桥梁检测技术现状的基础上,介绍国内外先进的检测技术,指出现有桥梁检测存在的问题,针对这些问题,分析桥梁检测技术的发展方向。 展开更多
关键词 轨道交通 桥梁 检测 发展趋势
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SNP芯片检测胎儿额外小标记染色体的研究 被引量:1
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作者 郑芳秀 史烨 +3 位作者 王晶 张峰 张晓青 虞斌 《中国现代医学杂志》 CAS 2019年第9期58-61,共4页
目的总结应用SNP芯片技术对胎儿额外小标记染色体(sSMC)进行鉴定的经验,为产前遗传咨询提供参考。方法应用传统G显带技术对2例胎儿羊水细胞及其父母外周血进行染色体核型分析,进一步用SNP芯片技术明确胎儿sSMC的来源。结果 1号胎儿羊水... 目的总结应用SNP芯片技术对胎儿额外小标记染色体(sSMC)进行鉴定的经验,为产前遗传咨询提供参考。方法应用传统G显带技术对2例胎儿羊水细胞及其父母外周血进行染色体核型分析,进一步用SNP芯片技术明确胎儿sSMC的来源。结果 1号胎儿羊水染色体核型为45,X[74]/46,X,+mar[31],芯片扫描结果为Xp22.33~p11.22和Xq27.3~q28区域均缺失,缺失大小分别为52.7和8.6 Mb。2号胎儿羊水染色体核型为47,XX,+mar,芯片结果为46,XX,其父亲外周血染色体核型为47,XY,+mar,临床表型正常。结论 SNP芯片可以确定s SMC的来源,可作为传统核型分析的补充,为产前诊断和遗传咨询提供帮助。 展开更多
关键词 产前诊断 额外小标记染色体/染色体 SNP芯片
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Enhancement of mechanical properties of GTAW joints for ZC63 magnesium alloy by post-weld heat treatment
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作者 Weiyang Zhou Qichi Le +4 位作者 ye shi Qiyu Liao Tong Wang Qi Zou Clodualdo Aranas Jr 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第2期251-263,共13页
To further improve the microstructure and mechanical properties of gas tungsten arc welded(GTAW)welded joints for ZC63 magnesium alloy,post-weld heat treatment is carried out.It is found that the majority of the MgZnC... To further improve the microstructure and mechanical properties of gas tungsten arc welded(GTAW)welded joints for ZC63 magnesium alloy,post-weld heat treatment is carried out.It is found that the majority of the MgZnCu phase in the fusion zone(FZ)is dissolved in theα-Mg matrix under suitable heat treatment conditions.The remainder is diffusely distributed as rods or granules at the grain bound-aries.The excessive heat treatment temperature(460℃)leads to abnormal grain growth(AGG)in the FZ.The substructure gradient between the abnormally grown grains and the surrounding small grains pro-vides the driving force for AGG.Meanwhile,the dissolution of the MgZnCu phase weakens the hindering effect of the second phase on grain boundary migration,setting the stage for AGG.In addition,the detri-mental impact of the continuous MgZnCu phase on the mechanical properties of the welded joint is also lessened by its dissolution.The ultimate tensile strength(UTS),yield strength(YS)and elongation(EL)of the welded joints are 255 MPa,119 MPa and 27.0%,respectively,under the post-weld heat treatment process of 440℃×12 h.The welding coefficient of the welded joint reaches 97.0%,satisfying the service criteria set forth by the mechanical properties of the welded joints. 展开更多
关键词 GTAW FZ Heat treatment AGG Mechanical properties
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An isoleucine-zipper motif enhances costimulation of human soluble trimeric GITR ligand
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作者 Dawei Cui Shengjun Wang +8 位作者 Yu Chen Jia Tong Jie Ma Li Tang Xianzhi Yang ye shi Jie Tian Liwei Lu Huaxi Xu 《Cellular & Molecular Immunology》 SCIE CAS CSCD 2010年第4期316-322,共7页
Glucocorticoid-induced tumor-necrosis factor receptor(GITR)and its ligand,GITRL,play significant roles in regulating immune responses.It is clear that human soluble GITRL(hsGITRL)transduces signal activity through mul... Glucocorticoid-induced tumor-necrosis factor receptor(GITR)and its ligand,GITRL,play significant roles in regulating immune responses.It is clear that human soluble GITRL(hsGITRL)transduces signal activity through multiple oligomerization states.To develop human soluble trimeric GITRL protein as a potential therapeutic target,we explored the link of the isoleucine-zipper(ILZ)motif to the N-terminus of the human soluble GITRL with two leucine sequences.hsGITRL,with the ILZ motif(ILZ-hsGITRL),was firstly expressed in Escherichia coli,which exhibited a predominant trimer when identified by Sephadex G-100 filtration and non-reducing SDS–polyacrylamide gel electrophoresis(SDS-PAGE).The significantly higher biological activity of the ILZ-hsGITRL compared with hsGITRL was confirmed by CD41 T proliferation,interferon-c(IFN-c)secretion and binding activity assay.To reveal and compare the underlying mechanisms,the level of extracellular signal-regulated kinase-1/2(ERK1/2)phosphorylation was examined,indicating that ILZ-hsGITRL induced more persistent and stronger ERK1/2 activation than hsGITRL.In conclusion,the incorporation of an ILZ motif could markedly improve the costimulation of hsGITRL. 展开更多
关键词 GITR ligand isoleucine zipper T cells
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