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地球关键带研究评述:现状与展望

土壤学报 2024年第2期61卷 308-318页

作者：杨顺华宋效东吴华勇吴克宁张甘霖土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所) 南京210008 中国地质大学(北京)土地科学技术学院北京100083 自然资源部土地整治重点实验室北京100035 中国科学院流域地理学重点实验室(中国科学院南京地理与湖泊研究所) 南京210008 中国科学院大学现代农业科学学院北京100049

近20年来,国际上兴起的“地球关键带”研究,为重新审视地球表层系统内水、土、气、生、岩等各要素的功能及其内在关联提供了新思路。通过搜集2001—2021年间国内外地球关键带研究文献,应用引文空间(CiteSpace)技术进行文献计量分析,梳... 详细信息

近20年来,国际上兴起的“地球关键带”研究,为重新审视地球表层系统内水、土、气、生、岩等各要素的功能及其内在关联提供了新思路。通过搜集2001—2021年间国内外地球关键带研究文献,应用引文空间(CiteSpace)技术进行文献计量分析,梳理地球关键带的研究历史与现状,为自然资源综合管理和国土空间生态修复提供理论依据和决策支持。文献分析表明:地球关键带受到欧美发达国家和中国学界的普遍关注;三个发展阶段(萌芽、初期和快速发展)的研究重点差异明显;土壤是联结地表和地下过程的纽带与核心;地球物理技术成为理解地球关键带结构与过程的重要工具;联网观测和模型模拟是下一阶段的重要方向;地球关键带功能和服务的量化、权衡与提升有望成为重要的决策支持工具。未来仍需在五个方面深化研究:加强基础设施建设,构建更具包容性的地球关键带观测站网络;加强学科交叉和人才队伍建设,培养新一代地球关键带科学家;服务面向可持续发展的社会需求,在实践中应用和发展地球关键带科学;开发新技术、新方法,完善理论、模型和方法体系;揭示地球关键带过程的耦合机制及其环境效应,加强人类活动对水土过程、物质循环与能量交换影响的研究。

关键词：地球关键带土壤圈地球表层系统结构过程服务

Experimental research of air-throttling ignition for a scramjet at Ma 6.5

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Chinese Journal of Aeronautics 2017年第3期30卷 932-938页

作者： Weixin DENG Jialing LE shunhua yang Wanzhou ZHANG Ye TIAN Science and Technology on Scramjet Lab Hypersonies Aerodynamics Institute China Aerodynamics Research and Development Center Mianyang 621000 China

An experimental investigation on ignition characteristics with air-throttling in an ethylene-fueled scramjet under flight Ma 6.5 conditions was *** dynamic process of air-throttling ignition was explored *** influences of throttling parameters,i.e.,throttling mass rate and duration,were *** the throttling mass rate was 45% of the inflow mass rate,ambient ethylene could be ignited *** delay time from ignition to throttling was about 45–55 *** was a threshold of throttling duration under a certain throttling mass *** was shorter than 100 ms when the throttling mass rate was 45%.While a 45%throttling mass rate would make the shock train propagate upstream to the isolator entry in about10–15 ms,four lower throttling mass rates were tested,including 30%,25%,20%,and 10%.All of these throttling mass rates could ignite ***,combustion performances varied with them.A higher throttling mass rate made more ethylene combust and produced higher wall *** these experiments,some aspects of the relationships between ignition,flame stabilization,combustion efficiency,and air-throttling parameters were brought to *** results could also be a benchmark for CFD validation.

关键词： Air-throttling Combustion Flame stabilization Ignition Scramjet Shock

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零间隙压气机失稳机理的全通道数值模拟研究

燃气轮机技术 2024年第1期37卷 1-7,15页

作者：张千丰杜娟游进杨顺华黄胜方北京流体动力科学研究中心北京100020 中国科学院工程热物理研究所北京100190

为了探究零间隙压气机流动失稳机理,采用全通道非定常数值模拟方法研究了一台零间隙斜流压气机转子的失稳机理,数值模拟过程中在转子出口施加了随时间动态变化的背压模拟压气机转子节流,非定常数值计算结果表明零间隙斜流压气机转子仍... 详细信息

为了探究零间隙压气机流动失稳机理,采用全通道非定常数值模拟方法研究了一台零间隙斜流压气机转子的失稳机理,数值模拟过程中在转子出口施加了随时间动态变化的背压模拟压气机转子节流,非定常数值计算结果表明零间隙斜流压气机转子仍然表现为典型突尖流动失稳特征。通过详细地分析斜流压气机转子节流过程中不同阀系数对应的压气机内部流场结构,结果表明:尽管零间隙斜流压气机无叶顶泄漏特征,但随着对压气机节流,转子叶片尾缘率先出现流动分离,进一步节流,尾缘流动分离表现为一方面在周向范围加剧,另一方面分离点逐渐向上游移动,造成通道严重堵塞,最终引发相邻叶片通道尾缘回流和叶片前缘流动溢出进而诱发叶片通道内部出现径向涡结构,从而形成压气机突尖失速先兆。

关键词：压气机叶顶间隙流动分离流动失稳全通道模拟

Systematic study of spatiotemporal influences on temporal contrast in the focal region in large-aperture broadband ultrashort petawatt lasers

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High Power Laser Science and Engineering 2018年第1期6卷 44-50页

作者： Ping Zhu Xinglong Xie Jun Kang Qingwei yang Haidong Zhu Ailin Guo Meizhi Sun Qi Gao Ziruo Cui Xiao Liang shunhua yang Dongjun Zhang Jianqiang Zhu Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

Temporal contrast is one of the crucial physical determinants which guarantee the successful performance of laser–matter interaction experiments. We generally reviewed the influences on the temporal contrast in three categories of noises based on the requirement by the physical mechanisms. The spatiotemporal influences on temporal contrast at the focal region of the chromatic aberration and propagation time difference introduced by large-aperture broadband spatial filters, which were spatiotemporally coupled with compression and focusing, were calculated and discussed with a practical case in SG-Ⅱ5 PW ultrashort petawatt laser. The system-wide spatiotemporal coupling existing in large-aperture broadband ultrashort petawatt lasers was proved to be one of the possible causes of temporal contrast degradation in the focal region.

关键词： chromatic aberration spatiotemporal coupling temporal contrast ultrashort petawatt lasers

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双气路内并联进气系统模态转换试验研究

气动研究与试验

气动研究与试验 2024年第3期2卷 69-80页

作者：母忠强杨顺华王铁军任虎游进谢松柏张弯洲罗佳茂北京流体动力科学研究中心北京100029 中国空气动力研究与发展中心、高超声速冲压发动机国防科技重点实验室四川绵阳621000

为了探究内并联进气系统模态转换过程中的分流板调节策略,利用地面试验研究方法,研究了Ma 3.5条件下双气路进气系统在典型分流板位置的流场干涉机制,获得了高低速气路总体性能和流场变化规律。研究结果表明,分流板高度变化影响高低速气... 详细信息

为了探究内并联进气系统模态转换过程中的分流板调节策略,利用地面试验研究方法,研究了Ma 3.5条件下双气路进气系统在典型分流板位置的流场干涉机制,获得了高低速气路总体性能和流场变化规律。研究结果表明,分流板高度变化影响高低速气路总体性能和抗反压能力,同时由于流量重新分配,下游动力系统的工作状态需要匹配调节;分流板调节对高速气路性能影响更显著,随着高速气路逐渐关闭,受激波强度变化影响,高速气路总压恢复系数会经历迅速下降再缓慢上升的过程;当出口反压比超过临界值,激波系会在分流板前缘和唇口之间以低频大振幅和高频小振幅相结合的方式往复运动,该非定常效应导致流场和总体性能不稳定,模态转换过程中应避免该情况发生。

关键词：组合发动机双气路进气系统模态转换分流板地面试验系统

Macro-microscopic dynamic characteristics of the ballast bed induced by the variation of moisture content

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Particuology 2024年第7期90卷 118-127页

作者： Shuchen Wang Longlong Fu Yongjia Qiu Haonan Xi shunhua Zhou Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China

Due to the excellent drainage performance of the ballast,existing studies mainly focus on the dynamic response of ballast under field capacity or *** has rarely been paid to dynamic changes in moisture content and potential *** this article,we firstly conduct a model test to determine the variation of ballast moisture content under artificial *** that,a full-scale model test with cyclic loading is carried out to study the effect of moisture content variation on the macro-microscopic response of the ballast bed,where several wireless particle sensors are installed to obtain ballast motion characteristics at strategic *** results show that the moisture content increases gradually and stabilizes at a flat peak under rainfall,despite the excellent drainage performance of ballast *** halting rainfall,the moisture content drops back to field capacity,which indicates dynamic flowing surface water on ballast particles under *** flowing surface water brings changes to the original dynamic equilibrium of ballast bed:macroscopically,the deformation rate of stabilized ballast bed increases significantly,reaching a local peak under field capacity;microscopically,the x-and z-angular accelerations of the ballast show positive correlation with rainfall *** multiscale responses indicate that field capacity is a critical moisture content.

关键词： Railway ballast Flowing surface water Wireless particle sensor Multidimensional motion Full-scale model test

Challenges and Prospects of Molecular Spintronics

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Precision Chemistry 2024年第1期2卷 1-13页

作者： Xianrong Gu Lidan Guo yang Qin Tingting yang Ke Meng shunhua Hu Xiangnan Sun Key Laboratory of Nanosystem and Hierarchical Fabrication National Center for Nanoscience and TechnologyBeijing 100190P.R.China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049P.R.China

Molecular spintronics,as an emerging field that makes full use of the advantage of ultralong room-temperature spin lifetime and abundant electrical-optical-magnetic properties of molecular semiconductors,has gained wide attention for its great potential for further commercial *** the significant progress that has been made,there remain several huge challenges that limit the future development of this *** Perspective provides discussions on the spin transport mechanisms and performances of molecular semiconductors,spinterface effect,and related spin injection in spintronic devices,and current spin-charge interactive functionalities,along with the summarization of the main obstacles of these ***,we particularly propose targeted solutions,aiming to enhance the spin injection and transport efficiency by molecular design and interface engineering and explore diverse spinrelated *** this Perspective,we hope it will help the spintronic community identify the research trends and accelerate the development of molecular spintronics.

关键词： Molecular spintronics spin transport spintronic materials spin injection spinterface effect spin-related functionality

Analysis and construction status of SG-Ⅱ 5PW laser facility

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High Power Laser Science and Engineering 2018年第2期6卷 110-122页

作者： Jianqiang Zhu Xinglong Xie Meizhi Sun Jun Kang Qingwei yang Ailin Guo Haidong Zhu Ping Zhu Qi Gao Xiao Liang Ziruo Cui shunhua yang Cheng Zhang Zunqi Lin National Laboratory on High Power Laser and Physics Shanghai 201800China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

We present a recent progress of the SG-II 5 PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification(OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum(FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric amplification(OPA), with the pump pulse that has an energy of 118 J from the second harmonic generation of the SG-II 7 th beam, the pump-to-signal conversion efficiency is up to 41.9%, which to the best of our knowledge is the highest among all of the reported values for OPCPA systems. The compressed pulse is higher than 37 J in 21 fs(1.76 PW), and the focal spot is ～10 μm after the closed-loop corrections by the adaptive optics. Limited by the repetition of the pump laser, the SG-II 5 PW facility operates one shot per hour. It has successfully been employed for high energy physics experiments.

关键词： conversion efficiency multi-petawatt optical parametric amplification proton acceleration ultrashort pulse

Exploring the feasibility of prestressed anchor cables as an alternative to temporary support in the excavation of super-large-span tunnel

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Railway Engineering Science 2024年第3期32卷 344-360页

作者： shunhua Zhou Yuyin Jin Zhiyao Tian Chunhua Zou Heming Zhao Zengrun Miao Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China China Railway Construction Corporation Limited Beijing 100855China The 2nd Engineering Co. Ltd.of China Railway Construction Bridge Engineering Bureau GroupShenzhen 518083China China Railway Construction Bridge Engineering Bureau Group Co. LtdTianjin 300300China

Excavating super-large-span tunnels in soft rock masses presents significant *** ensure safety,the sequential excavation method is commonly *** utilizes internal temporary supports to spatially partition the tunnel face and divide the excavation into multiple ***,these internal supports generally impose spatial constraints,limiting the use of large-scale excavation equipment and reducing construction *** address this constraint,this study adopts the“Shed-frame”principle to explore the feasibility of an innovative support system,which aims to replace internal supports with prestressed anchor cables and thus provide a more spacious working space with fewer internal *** evaluate its effectiveness,a field case involving the excavation of a 24-m span tunnel in soft rock is presented,and an analysis of extensive field data is conducted to study the deformation characteristics of the surrounding rock and the mechanical behavior of the support *** results revealed that prestressed anchor cables integrated the initial support with the shed,creating an effective“shed-frame”system,which successively maintained tunnel deformation and frame stress levels within safe regulatory ***,the prestressed anchor cables bolstered the surrounding rock effectively and reduced the excavation-induced disturbance zone *** summary,the proposed support system balances construction efficiency and *** field experiences may offer valuable insights into the popularization and further development of prestressed anchor cable support systems.

关键词： Super-large-span tunnel Construction safety Sequential excavation method Shed-frame principle Prestressed anchor cables