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Tropism-shifted AAV-PHP.eB-mediated bFGF gene therapy promotes varied neurorestoration after ischemic stroke in mice
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作者 Rubing Shi Jing Ye +10 位作者 Ze Liu cheng wang Shengju Wu Hui Shen Qian Suo Wanlu Li Xiaosong He Zhijun Zhang Yaohui Tang Guo-Yuan Yang Yongting wang 《Neural Regeneration Research》 2026年第2期704-714,共11页
AAV-PHP.eB is an artificial adeno-associated virus(AAV)that crosses the blood-brain barrier and targets neurons more efficiently than other AAVs when administered systematically.While AAV-PHP.eB has been used in vario... AAV-PHP.eB is an artificial adeno-associated virus(AAV)that crosses the blood-brain barrier and targets neurons more efficiently than other AAVs when administered systematically.While AAV-PHP.eB has been used in various disease models,its cellular tropism in cerebrovascular diseases remains unclear.In the present study,we aimed to elucidate the tropism of AAV-PHP.eB for different cell types in the brain in a mouse model of ischemic stroke and evaluate its effectiveness in mediating basic fibroblast growth factor(bFGF)gene therapy.Mice were injected intravenously with AAV-PHP.eB either 14 days prior to(pre-stroke)or 1 day following(post-stroke)transient middle cerebral artery occlusion.Notably,we observed a shift in tropism from neurons to endothelial cells with post-stroke administration of AAV-PHP.eB-mNeonGreen(mNG).This endothelial cell tropism correlated strongly with expression of the endothelial membrane receptor lymphocyte antigen 6 family member A(Ly6A).Furthermore,AAV-PHP.eB-mediated overexpression of bFGF markedly improved neurobehavioral outcomes and promoted long-term neurogenesis and angiogenesis post-ischemic stroke.Our findings underscore the significance of considering potential tropism shifts when utilizing AAV-PHP.eB-mediated gene therapy in neurological diseases and suggest a promising new strategy for bFGF gene therapy in stroke treatment. 展开更多
关键词 AAV-PHP.eB angiogenesis basic fibroblast growth factor gene therapy ischemic stroke Ly6A neurogenesis neurological function transient middle cerebral artery occlusion TROPISM
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泵站技术供水系统改造研究——以常熟枢纽泵站为例
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作者 张逸远 徐敏杰 +1 位作者 程旺 张纯杰 《镇江高专学报》 2026年第1期100-105,共6页
技术供水系统是泵站机组降低油温、提供润滑的重要系统。常熟枢纽泵站技术供水系统长期抽取望虞河河水,此举易出现系统堵塞、冷却效率低、腐蚀管道、污染环境等问题。介绍常熟枢纽泵站技术供水系统改造过程,对比改造前、后系统的布置形... 技术供水系统是泵站机组降低油温、提供润滑的重要系统。常熟枢纽泵站技术供水系统长期抽取望虞河河水,此举易出现系统堵塞、冷却效率低、腐蚀管道、污染环境等问题。介绍常熟枢纽泵站技术供水系统改造过程,对比改造前、后系统的布置形式,分析改造后系统具有的优势。改造后的技术供水系统在循环运行、冷却效率、经济效益、生态友好等方面水平有显著提升,探讨改造后系统可能遭遇的问题,相关结论可为类似泵站的技术供水系统改造提供参考。 展开更多
关键词 技术供水系统 常熟枢纽 大型泵站 闭式循环
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汉朝和希腊化文明的接触与丝绸之路的开通
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作者 徐晓旭 徐阳 《吉林大学社会科学学报》 北大核心 2025年第4期190-196,共7页
关于丝绸之路的开通常有两类意见:张骞开通的[1-2];张骞之前就存在[3-4]。然而,大家更多关注的是“路”的有无,而非路上“丝绸”的有无。我们更关心后者,即这条路上何时和怎样开始常规性丝绸贸易的。我们重构的历史如下:在张骞开启汉朝... 关于丝绸之路的开通常有两类意见:张骞开通的[1-2];张骞之前就存在[3-4]。然而,大家更多关注的是“路”的有无,而非路上“丝绸”的有无。我们更关心后者,即这条路上何时和怎样开始常规性丝绸贸易的。我们重构的历史如下:在张骞开启汉朝与中亚、西亚各国接触之前,中国丝绸的传播仅限于东亚。在与这些国家频繁的外交往来中,汉使除携带丝绸作为国礼外,还需在当地自行支付生活费用,但汉朝的货币与当地的希腊化货币并不兼容,汉使只能使用丝绸充当支付手段,这就导致丝绸进入国际市场并颇受欢迎。 展开更多
关键词 汉朝 希腊化文明 丝绸之路 张骞 丝绸贸易
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智能算网的基础理论与核心技术 被引量:2
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作者 高文 钱德沛 +4 位作者 朱美芳 蒋昌俊 王成 杜鑫 潘庆 《中国科学基金》 北大核心 2025年第2期194-207,共14页
为了应对全球科技竞争的挑战并满足日益增长的算力需求,我国于2022年启动了“东数西算”等重大战略工程,致力于构建新型算力网络(简称“算网”)体系,以提升新质生产力并实现全国算力资源的均衡分布与高效利用。算网应聚焦于资源适配、... 为了应对全球科技竞争的挑战并满足日益增长的算力需求,我国于2022年启动了“东数西算”等重大战略工程,致力于构建新型算力网络(简称“算网”)体系,以提升新质生产力并实现全国算力资源的均衡分布与高效利用。算网应聚焦于资源适配、调度、交易、配送和安全等方面的前沿研究,突破其在灵性资源适配、弹性供需优配以及韧性安全可信等方面的技术瓶颈,强化算网对需求与资源的重构能力、交易与复杂调度任务中的响应与优化能力以及攻击与风险的防御与保障能力,构建支持算力、算法和数据等新型生产要素一体化统筹调配的“柔性”智能算网,满足新材料等计算密集型业务在复杂的计算模拟、结构预测和性能优化方面以及新金融等数据和计算密集型业务在安全可控的计算环境、高效的分布式协同以及实时性和高复杂性的计算方面的迫切需求,以支撑国家在新金融、新材料、新信息和新管理等前沿领域的创新发展,增强我国在全球科技竞争中的战略优势。基于第371期“双清论坛”,本文总结了我国算网建设的现状与面临的重大挑战,回顾了算网建设所取得的主要进展和成就,凝练了该领域未来5~10年的重大关键科学问题,探讨了前沿研究方向和科学基金资助战略。 展开更多
关键词 算力网络 智能算网 可重构计算 需求动态适配 算力交易调度 可信安全
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湖南张家界大鲵国家级自然保护区中国大鲵种群动态及保护策略
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作者 田书荣 魏营 +6 位作者 肖芬 周芸芸 解宜兴 王丞 宋芬 梁志强 桂小杰 《生物多样性》 北大核心 2025年第7期56-66,共11页
种群动态分析是制定濒危物种保护策略的重要依据。中国大鲵(Andrias davidianus)为我国特有两栖动物,其野外种群状况不明。为探讨种群增长模型在种群动态分析及物种保护成效量化评价中的可行性,本文以湖南张家界大鲵国家级自然保护区的... 种群动态分析是制定濒危物种保护策略的重要依据。中国大鲵(Andrias davidianus)为我国特有两栖动物,其野外种群状况不明。为探讨种群增长模型在种群动态分析及物种保护成效量化评价中的可行性,本文以湖南张家界大鲵国家级自然保护区的中国大鲵为研究对象,基于2006-2021年的野外调查数据和2000-2024年的增殖放流统计数据,应用种群增长模型模拟分析了该保护区中国大鲵的种群动态、环境容纳量及增殖放流效果。结果表明:(1)该种群年均增长率为0.1722±0.0324,环境容纳量K值为51,190条,目前种群处于指数增长阶段;(2)中国大鲵种群在增殖放流和无增殖放流两种情形下,其种群增长曲线呈现极显著差异。在无增殖放流情形下,种群指数和Logistic增长模型中的瞬时增长率分别下降了16.27%和32.11%。(3)增殖放流对中国大鲵野生种群复壮效果明显,按照目前增殖放流量测算,40年后种群数量将达到环境容纳量的峰值。基于种群增长模型分析种群动态具有可行性,其研究成果对制定中长期濒危物种保护策略具有较好的应用前景;对张家界大鲵保护区中国大鲵种群动态分析研究结果显示,增殖放流(种群补充)效果明显;中国大鲵种群增长率相对较低,实施增殖放流和栖息地修复等保护措施十分必要。鉴于目前的种群增长率、种群增长趋势及环境容纳量,建议持续实施增殖放流措施,并按水系和遗传支系筛选增殖放流个体,以本地亲本繁育后代为增殖放流个体来源,防止野生种群基因混杂并确保种群稳定增长,重点加强出苗点的保护和恢复。本结果可为中国大鲵或其他濒危物种种群动态分析、保护成效评估和保护策略制定提供参考。 展开更多
关键词 中国大鲵 濒危物种 种群动态 种群增长模型 保护策略 湖南张家界大鲵国家级自然保护区
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A review of superplastic magnesium alloys:Focusing on alloying strategy,grain structure control and deformation mechanisms 被引量:2
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作者 Siqing wang Min Zha +5 位作者 Hailong Jia Yajie Yang Dawei wang cheng wang Yipeng Gao Hui-Yuan wang 《Journal of Materials Science & Technology》 2025年第8期303-319,共17页
In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a m... In response to the urgent demand for lightweight,magnesium(Mg)alloys have garnered considerable attention owing to their low density.Nonetheless,the intrinsic poor room-temperature formability of Mg alloys remains a major obstacle in shaping precise complex components,necessitating the development of superplastic Mg alloys.Excellent superplasticity is usually acquired in high-alloyed Mg alloys with enhanced microstructural thermal stability facilitated by abundant optimized second-phase particles.While for cost-effective low-alloyed Mg alloys lacking particles,regulating solute segregation has emerged as a promising approach to achieve superplasticity recently.Moreover,the potential of bimodal-grained Mg alloys for superplastic deformation has been revealed,expanding the options for designing superplastic materials beyond the conventional approach of fine-grained microstructures.This study reviews significant developments in superplastic Mg alloys from the view of alloying strategies,grain structure control and deformation mechanisms,with potential implications for future research and industrial applications of superplastic Mg alloys. 展开更多
关键词 Mg alloys SUPERPLASTICITY Second-phase particles Solute segregation Microstructure control
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Adjustable corrosion and mechanical properties of Mg-Zn-Ca-Ni alloys for fracturing materials 被引量:2
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作者 Dawei wang Xiangshuang Jiang +7 位作者 Changxin Chen Xun Zhang Zhong-Zheng Jin Fuyong Cao Jia-Ning Zhu cheng wang Yinlong Ma Min Zha 《Journal of Magnesium and Alloys》 2025年第6期2618-2635,共18页
Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring... Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials. 展开更多
关键词 Mg-Zn-Ca alloy Fracturing material Galvanic corrosion Corrosion barrier
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A theoretical and experimental study of deformation mechanism dictated by disclination-dislocation coupling in Mg alloys at different temperatures 被引量:1
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作者 Chunfeng Du Yipeng Gao +5 位作者 Yizhen Li Quan Li Min Zha cheng wang Hailong Jia Hui-Yuan wang 《Journal of Materials Science & Technology》 2025年第5期176-188,共13页
Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dyna... Dislocations and disclinations are fundamental topological defects within crystals,which determine the mechanical properties of metals and alloys.Despite their important roles in multiple physical mechanisms,e.g.,dynamic recovery and grain boundary mediated plasticity,the intrinsic coupling and correlation between disclinations and dislocations,and their impacts on the deformation behavior of metallic materials still remain obscure,partially due to the lack of a theoretical tool to capture the rotational nature of disclinations.By using a Lie-algebra-based theoretical framework,we obtain a general equation to quantify the intrinsic coupling of disclinations and dislocations.Through quasi in-situ electron backscatter diffraction characterizations and disclination/dislocation density analyses in Mg alloys,the generation,coevolution and reactions of disclinations and dislocations during dynamic recovery and superplastic deformation have been quantitatively analyzed.It has been demonstrated that the obtained governing equation can capture multiple physical processes associated with mechanical deformation of metals,e.g.,grain rotation and grain boundary migration,at both room temperature and high temperature.By establishing the disclination-dislocation coupling equation within a Lie algebra description,our work provides new insights for exploring the coevolution and reaction of disclinations/dislocations,with profound implications for elucidating the microstructure-property relationship and underlying deformation mechanisms in metallic materials. 展开更多
关键词 Magnesium alloys Dislocations Grain boundaries Plastic deformation Grain rotation Disclination-dislocation coupling
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《实践论》与“第二个结合”的早期探索
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作者 刘孙怡 程旺 《世纪桥》 2025年第19期7-10,共4页
毛泽东同志为马克思主义基本原理同中华优秀传统文化相结合作出了历史性贡献。《实践论》是马克思主义基本原理同中华优秀传统文化相结合的光辉典范,坚持马克思主义立场、观点、方法,继承中华优秀传统文化的思想精华,科学分析中国新民... 毛泽东同志为马克思主义基本原理同中华优秀传统文化相结合作出了历史性贡献。《实践论》是马克思主义基本原理同中华优秀传统文化相结合的光辉典范,坚持马克思主义立场、观点、方法,继承中华优秀传统文化的思想精华,科学分析中国新民主主义革命的时代特征和主要矛盾,既开辟了马克思主义中国化新境界,也为传承发展中华优秀传统文化提供了方向性指引。文章探析《实践论》在“第二个结合”中的理论贡献,可为新时代推进“两个结合”提供重要思想资源。 展开更多
关键词 “第二个结合” 《实践论》 马克思主义 中华优秀传统文化
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Novel titanium vanadate with superior Na^(+) transport kinetics for rapid charging and low-temperature sodium ion batteries 被引量:1
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作者 Dan Lv Liehao Wei +6 位作者 cheng wang Mingyue wang Zhongchao Bai Yameng Fan Dongdong wang Nana wang Jian Yang 《Green Energy & Environment》 2025年第2期374-381,共8页
Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kineti... Sodium-ion batteries(SIBs)hold great promise for large-scale energy storage in the post-lithium-ion battery era due to their high rate performance and long lifespan,although their sluggish Na^(+) transformation kinetics still require improvement.Encouraged by the excellent electrochemical performance of titanium-based anode materials,here,we present a novel titanium vanadate@carbon(TVO@C)material as anode for SIBs.Our TVO@C material is synthesized via a facile coprecipitation method,with the following annealing process in an acetylene atomosphere.The opened ion channel and the oxygen vacancies within TVO@C facilitate the diffusion of Na^(+) ions,reducing their diffusion barrier.Thus,an ultrahigh rate of 100 A g^(-1)and long life of 10,000 cycles have been achieved.Furthermore,the TVO@C electrode exhibits stable performance,not only at room temperature,but also at temperatures as low as 20 C.The TVO@CjjNa_(3)V_(2)(PO_(4))_(3)@C full cells have also achieved stable discharge/charge for 500 cycles.It is believed that this strategy provides new insight into the development of advanced electrodes and provides a new opportunity for constructing novel high rate electrodes. 展开更多
关键词 Anode High rate Titanium vanadate Sodium ion batteries
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基于有限元分析的笔记本纸浆模塑包装方案研究
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作者 张书炜 程旺 +3 位作者 韦明堂 张倩 张湘钰 黄梦凯 《包装工程》 北大核心 2025年第3期238-244,共7页
目的设计出一款低重量、高栈板量的笔记本电脑纸浆模塑(简称纸塑)包装方案,预估及验证新方案在跌落测试中对电脑的保护性。方法结合现有内翻和外翻纸塑方案各自结构的优势,设计出一种V型纸塑方案。基于跌落试验工况建立跌落仿真模型,通... 目的设计出一款低重量、高栈板量的笔记本电脑纸浆模塑(简称纸塑)包装方案,预估及验证新方案在跌落测试中对电脑的保护性。方法结合现有内翻和外翻纸塑方案各自结构的优势,设计出一种V型纸塑方案。基于跌落试验工况建立跌落仿真模型,通过ANSYS/LS-Dyna进行仿真分析,得到产品跌落加速度曲线和纸塑开裂变形图,并进行测试验证。结果V型方案在端面、顶面和短棱跌落的加速度均低于原内翻方案,各工况下V型方案无明显开裂,仿真分析与跌落测试结果高度一致。结论V型方案可在跌落测试中对电脑提供充分保护,满足落地条件,具有巨大的经济价值。有限元分析结果精度较高,可为各机型纸塑包装的开模定形提供依据,降低修模风险。 展开更多
关键词 纸浆模塑 仿真分析 加速度 纸塑开裂 跌落试验
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贵州梵净山国家级自然保护区鸟兽红外相机监测 被引量:29
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作者 张明明 杨朝辉 +6 位作者 王丞 王娇娇 胡灿实 雷孝平 石磊 粟海军 李佳琦 《生物多样性》 CAS CSCD 北大核心 2019年第7期813-818,共6页
红外相机监测是了解野生动物多样性现状、动态变化和面临威胁的重要手段。本研究采用网格抽样调查法,在贵州梵净山国家级自然保护区内选取2个监测样区共40个监测位点布设红外相机,对区内兽类和鸟类物种进行监测调查。2017年4月至2018年1... 红外相机监测是了解野生动物多样性现状、动态变化和面临威胁的重要手段。本研究采用网格抽样调查法,在贵州梵净山国家级自然保护区内选取2个监测样区共40个监测位点布设红外相机,对区内兽类和鸟类物种进行监测调查。2017年4月至2018年12月间,红外相机累积监测14,808个相机工作日,共收集有效照片14,119张,独立有效物种照片3,199张。共鉴定野生动物9目22科61种,其中兽类26种,隶属于4目12科;鸟类35种,隶属于5目10科。记录到国家I级重点保护野生动物2种:黔金丝猴(Rhinopithecusbrelichi)和白颈长尾雉(Syrmaticusellioti),国家II级重点保护野生动物9种;被IUCN红色名录评估为濒危(EN)的1种、易危(VU)的5种、近危(NT)的8种。物种的相对多度指数(relative abundance index, RAI)分析结果显示,藏酋猴(Macaca thibetana, RAI=28.23)、毛冠鹿(Elaphodus cephalophus, RAI=15.46)、野猪(Sus scrofa, RAI=11.82)、小麂(Muntiacus reevesi, RAI=9.05)、黔金丝猴(RAI=7.70)为相对多度最高的5种兽类;紫啸鸫(Myophonus insularis, RAI=10.33)、红腹角雉(Tragopan temminckii, RAI=9.59)、红腹锦鸡(Chrysolophus pictus, RAI=6.96)、白颈长尾雉(RAI=3.71)、勺鸡(Pucrasia macrolopha, RAI=1.55)为相对多度最高的5种鸟类。另外,红外相机还监测到较多的家畜活动(RAI=11.14)和人为活动(RAI=12.90),保护区管理部门仍需采取相应管理措施,进一步提高周边居民的保护意识,促进保护区与社区的协调发展。 展开更多
关键词 兽类 鸟类 物种多样性 红外相机监测 梵净山国家级自然保护区
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A Short-Term Traffic Flow Forecasting Method Based on a Three-Layer K-Nearest Neighbor Non-Parametric Regression Algorithm 被引量:7
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作者 Xiyu Pang cheng wang Guolin Huang 《Journal of Transportation Technologies》 2016年第4期200-206,共7页
Short-term traffic flow is one of the core technologies to realize traffic flow guidance. In this article, in view of the characteristics that the traffic flow changes repeatedly, a short-term traffic flow forecasting... Short-term traffic flow is one of the core technologies to realize traffic flow guidance. In this article, in view of the characteristics that the traffic flow changes repeatedly, a short-term traffic flow forecasting method based on a three-layer K-nearest neighbor non-parametric regression algorithm is proposed. Specifically, two screening layers based on shape similarity were introduced in K-nearest neighbor non-parametric regression method, and the forecasting results were output using the weighted averaging on the reciprocal values of the shape similarity distances and the most-similar-point distance adjustment method. According to the experimental results, the proposed algorithm has improved the predictive ability of the traditional K-nearest neighbor non-parametric regression method, and greatly enhanced the accuracy and real-time performance of short-term traffic flow forecasting. 展开更多
关键词 Three-Layer Traffic Flow Forecasting K-Nearest Neighbor Non-Parametric Regression
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经皮椎间孔镜技术在腰椎手术失败综合征中的应用 被引量:6
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作者 李学林 晏怡果 +5 位作者 薛静波 王程 胡文凯 欧阳智华 刘祥和 王文军 《中国内镜杂志》 2021年第6期74-78,共5页
目的探讨采用经皮椎间孔镜技术进行翻修手术治疗腰椎手术失败综合征的临床疗效。方法回顾性分析2012年1月-2017年6月该科室28例采用经皮椎间孔镜技术进行翻修手术治疗腰椎手术失败综合征的患者的临床资料。分析患者翻修手术前后腿痛视... 目的探讨采用经皮椎间孔镜技术进行翻修手术治疗腰椎手术失败综合征的临床疗效。方法回顾性分析2012年1月-2017年6月该科室28例采用经皮椎间孔镜技术进行翻修手术治疗腰椎手术失败综合征的患者的临床资料。分析患者翻修手术前后腿痛视觉模拟评分(VAS),采用MacNab标准评估再次手术后的临床疗效。结果 28例患者均顺利完成椎间孔镜手术,手术时间55~95 min,平均(62.2±5.5) min;术前腿痛VAS评分为(8.1±0.3)分,术后腿痛VAS评分为(2.6±0.2)分,术前术后比较,差异有统计学意义(P <0.05)。按MacNab功能评定标准:优11例、良14例、可1例、差2例,整体满意度为89.3%。结论对于有手术适应证的腰椎手术失败综合征患者,可选择经皮椎间孔镜技术行翻修手术。 展开更多
关键词 腰椎手术失败综合征 椎间孔镜 翻修 复发 微创
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化学类专业无机化学课程群设置与教学内容——以厦门大学为例 被引量:12
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作者 朱亚先 匡勤 +3 位作者 汪骋 黄荣彬 杨士烑 郑兰荪 《大学化学》 CAS 2020年第8期1-5,共5页
无机化学类课程是化学类专业学生的主要课程之一,对培养目标与毕业要求的达成起到重要的支撑作用。本文以厦门大学为例,对无机化学课程群课程设置与教学内容进行了探索。
关键词 化学类专业 无机化学 课程设置 教学内容
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基于取食行为探究北京居民区鸟类的食源特征及多样性 被引量:9
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作者 殷鲁秦 王成 韩文静 《生物多样性》 CAS CSCD 北大核心 2023年第5期33-46,共14页
城市是鸟类的重要栖息地,城市绿地中占比最大的为居住绿地,是容纳鸟类的重要生境。对于鸟类生存来说,食物的种类和数量是关键的限制因子。本研究从鸟类的食物偏好入手,旨在构建北京居住区鸟类的食源关系,探究鸟类在居住区中取食的影响... 城市是鸟类的重要栖息地,城市绿地中占比最大的为居住绿地,是容纳鸟类的重要生境。对于鸟类生存来说,食物的种类和数量是关键的限制因子。本研究从鸟类的食物偏好入手,旨在构建北京居住区鸟类的食源关系,探究鸟类在居住区中取食的影响因素。研究选取40个居住小区作为调查样地,于2020年6月至2021年5月每月调查1次,采用广义线性模型评估鸟类在居住区中取食的影响因素,并对鸟类的食源多样性指数与多度、分布范围进行线性回归。结果表明:(1)本研究共记录到取食行为的鸟种共14科35种2,242只,丰富度为春季>秋季>冬季>夏季,多度为春季>冬季>秋季>夏季,Shannon-Wiener多样性指数为秋季>春季>冬季>夏季。(2)鸟类的食源依次为昆虫(33.87%)、翅果(18.33%)、浆果(9.77%)、球果(8.16%)、草籽(5.17%)等。(3)鸟类对植物的直接利用高达60.4%,间接利用为39.6%,食源植物Shannon-Wiener多样性指数为秋季(3.1612)>冬季(2.9651)>春季(2.9203)>夏季(2.1763)。(4)食源树种是影响鸟类在居住区中取食最关键的外界环境因素,食源越丰富的鸟种,其种群数量越大,分布范围越广泛。居住区的食源植物具有类型丰富、种类繁多、从早春到晚秋覆盖全物候的特点,在规划设计时应多配置北京乡土树种以及金银木(Loniceramaackii)等观果植物,减少绿篱配置,倡导低干扰的近自然园林养护管理措施。 展开更多
关键词 鸟类食性 居住区 食物来源 食源植物 鸟类多样性 北京
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Temporal Pulse Engineering of Spectral Evolution in a Synthetic Frequency Lattice
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作者 Jingkun Zhuang Qunchao Ma +6 位作者 Zhenyu Jiang Mingjin Yang Zhuochao Tie Yan Liang cheng wang Songlin Zhuang Qingqing cheng 《Chinese Physics Letters》 2025年第10期83-100,共18页
Precise experimental control and characterization of electron wave packet dynamics driven by external optical fields remain a fundamental challenge,particularly at ultrafast temporal and sub-microscopic spatial scales... Precise experimental control and characterization of electron wave packet dynamics driven by external optical fields remain a fundamental challenge,particularly at ultrafast temporal and sub-microscopic spatial scales.To overcome these challenges,we introduce a photon-based simulation platform employing a traveling-wave electrooptic phase-modulated waveguide.In our setup,the incident electromagnetic pulse serves as an analog to the electron wave packet,while the traveling-wave modulation simulates the external optical driving field.Our experimental study systematically explores pulse evolution under three distinct regimes defined by the relation between the pulse duration(Δt)and the modulation period(T).When the pulse duration is significantly shorter than the modulation period,we observe a uniform spectral shift analogous to electron acceleration in dielectric laser accelerators,where spectral phase gradients represent electron momentum accumulation.Conversely,when the pulse duration greatly exceeds the modulation period,discrete diffraction patterns emerge,closely resembling the discrete sideband features of electron-photon coupling observed in photon-induced near-field electron microscopy.Notably,in the intermediate regime(T/4<Δt<T/2),the pulse spectrum exhibits Airy-function-type characteristics with self-healing effects.These experimental results provide critical insights into electron-wave interactions under external optical fields and establish a robust,programmable framework for further investigation. 展开更多
关键词 external optical fields spectral evolution temporal pulse engineering electron wave packet incident electromagnetic pulse synthetic frequency lattice photon based simulation platform electron wave packet dynamics
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Gust alleviation H_(∞)control law design and wind tunnel test for a high-aspect-ratio flexible wing
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作者 cheng wang Jinge YU +4 位作者 Yingdong XIA Jiayu CHEN Yuxuan YAO Mingying HUO Naiming QI 《Chinese Journal of Aeronautics》 2025年第10期384-402,共19页
High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,an... High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,and good stealth performance.However,compared to conventional aircraft,high-aspect-ratio aircraft are more susceptible to gust disturbances during flight.In response to this phenomenon,a full-scale dynamic model of a high-aspect-ratio unmanned aerial vehicle was developed.Considering the coupling among control surfaces,structural forces,and aerodynamic forces,along with sensor,actuator,and delay effects,an H_(∞)control law was designed using the principle of singular value energy flow reduction and weighted function,with a PID(Proportional-Integral-Derivative)control law for comparison.The two controllers were then subjected to pulse-response and jury stability tests.Finally,wind tunnel tests were conducted to investigate the gust alleviation principle,in which gust disturbances were generated using gust generators and control surface self-excitation.The results present that the average wing root bending moment and wing tip overload under the PID control law decrease by approximately 30%,while under the H_(∞)control law,both the average wing root bending moment and wing tip overload reduction rate exceed 50%,with peaks reaching 60%.This validates the feasibility and efficiency of the designed H_(∞)controller. 展开更多
关键词 Gust alleviation active control H_(∞)control law Large-aspect-ratio flexible wing Root bending moment Wind tunnel test Wing tip loads
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Frequency regulation reserve optimization of wind-PV-storage power station considering online regulation contribution
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作者 Changping Sun Xiaodi Zhang +4 位作者 Wei Zhang Jiahao Liu Zubing Zou Leying Li cheng wang 《Global Energy Interconnection》 2025年第3期433-446,共14页
The frequency regulation reserve setting of wind-PV-storage power stations is crucial.However,the existing grid codes set up the station reserve in a static manner,where the synchronous generator characteristics and f... The frequency regulation reserve setting of wind-PV-storage power stations is crucial.However,the existing grid codes set up the station reserve in a static manner,where the synchronous generator characteristics and frequency-step disturbance scenario are considered.Thus,the advantages of flexible regulation of renewable generations are wasted,resulting in excessive curtailment of wind and solar resources.In this study,a method for optimizing the frequency regulation reserve of wind PV storage power stations was developed.Moreover,a station frequency regulation model was constructed,considering the field dynamic response and the coupling between the station and system frequency dynamics.Furthermore,a method for the online evaluation of the station frequency regulation was proposed based on the benchmark governor fitting.This method helps in overcoming the capacity-based reserve static setting.Finally,an optimization model was developed,along with the proposal of the linearized solving algorithm.The field data from the JH4#station in China’s MX power grid was considered for validation.The proposed method achieves a 24.77%increase in the station income while ensuring the system frequency stability when compared with the grid code-based method. 展开更多
关键词 Frequency stability Wind-PV-storage power station Frequency regulation Reserve optimization Frequency dynamics Benchmark governor
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Design of a cryogenic photocathode gun with a novel TM02 mode coupler for low emittance
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作者 Jia-Hao Tian cheng wang +1 位作者 Wen-cheng Fang Zhen-Tang Zhao 《Nuclear Science and Techniques》 2025年第11期109-120,共12页
The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the... The application of radiofrequency(RF)electron guns operating at cryogenic temperatures can enhance the performance of a photoinjector.The low emittance and increased brightness of the electron beams resulting from the high gradient in the cryogenic photoinjector make it possible to improve the performance of new light sources.As an upgrading scheme for the Shanghai Soft X-ray Free-Electron Laser,this study explores a novel photocathode RF gun by introducing the TM_(02)mode into the cathode cell of a 2.6-cell electron gun,which improves the RF performance,particularly in terms of the monopole field.Furthermore,the optimized cathode cell with the TM_(02)mode can reduce the errors resulting from installation and decrease the dark current with alternative cathodes.In this study,the beam dynamics in a photoinjector were optimized using a 500-pC,5-ps beam,and its feasibility was examined.This paper presents the entire RF design process,including the adjustment of the RF structure,coupler design,local field,and multipole mode suppression to provide theoretical guidance for subsequent manufacturing and assembly. 展开更多
关键词 Accelerator physics Cryogenic photoinjector RF gun structure Beam dynamics C-BAND Residual resistivity ratio(RRR)
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