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Great influence of demagnetization history on internal interaction and magnetization process of mischmetal-based magnets

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 183-192页

作者： Dan Liu Jiefu Xiong Lichen Wang Xinqi Zheng Xin Ming Jiaying Jin Jiazheng Hao He Bai Zhenxing Li Tongyun Zhao Fengxia Hu Jirong Sun Jun shen Baogen shen Department of Physics Beijing Technology and Business UniversityBeijing 10048China Ningbo Institute of Materials Technology&Engineering Chinese Academy of SciencesNingbo 31521China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Spallation Neutron Source Science Center Dongguan 523803China School of Mechanical Engineering Beijing Institute of Technology Beijing 100081China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 101408China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China

The magnetization process and corresponding magnetization curve are usually used to analyze the coercivity mechanism of NdFe-B based sintered ***,different demagnetization histories will seriously influence the magnetization curve,leading to an inaccurate understanding and analysis of magnetization *** this work,we investigated the magnetization behavior of multi-main phase(MMP)magnets with thermal demagnetized and alternating current demagnetized *** curves of initial magnetization process and demagnetization process of thermal demagnetized magnets reflect the movement of domain walls inside the grains and the magnetization interaction between the grains,*** is noted that the former process cannot represent the magnetization reversal of the entire magnet,which is not appropriate to analyze coercivity mechanism *** the recoil curves of both two processes of AC demagnetized magnets can illustrate the magnetization reversal of the entire grains and the interaction between ***-optical Kerr microscope shows that the grains of thermal demagnetized magnets are in multi-domain states,and the grains of AC demagnetized magnets are almost in singledomain *** walls of thermal demagnetized magnets move easily within the grains,which is more conducive to magnetization saturation in industrial *** addition,the minorloops of thermal demagnetized magnets can independently represent the transition of grains from multi-domain to single-domain and the demagnetization of single-domain grains,which is equivalent to characterizing the internal interactions by recoil *** investigation of magnetization characteristics of MMP sintered magnets starting from different demagnetized states is helpful to further understand the internal interaction and magnetic hardening mechanism.

关键词： permanent magnet demagnetization history magnetization reversal misch-metal rare earth

Detection of Perfect Stealthy Attacks on Cyber-Physical Systems Subject to Measurement Quantizations: A Watermark-Based Strategy

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 114-125页

作者： Yu-Ang Wang Zidong Wang Lei Zou Bo shen Hongli Dong the College of Information Science and Technology Donghua University the Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of Education IEEE the College of Electrical Engineering and Automation Shandong University of Science and Technology the Department of Computer Science Brunel University London Uxbridge the Sanya Offshore Oil and Gas Research Institute Northeast Petroleum University the Artificial Intelligence Energy Research Institute Northeast Petroleum University Heilongjiang Provincial Key Laboratory of Networking and Intelligent Control Northeast Petroleum University

In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.

关键词： Attack detection cyber-physical systems (CPSs) perfect stealthy attacks watermark-based strategy

Mechanism by which Rab5 promotes regeneration and functional recovery of zebrafish Mauthner axons

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Neural Regeneration Research 2025年第6期20卷 1816-1824页

作者： Jiantao Cui Yueru shen Zheng Song Dinggang Fan Bing Hu Center for Advanced Interdisciplinary Science and Biomedicine of IHM Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina

Rab5 is a GTPase protein that is involved in intracellular membrane trafficking. It functions by binding to various effector proteins and regulating cellular responses, including the formation of transport vesicles and their fusion with the cellular membrane. Rab5 has been reported to play an important role in the development of the zebrafish embryo;however, its role in axonal regeneration in the central nervous system remains unclear. In this study, we established a zebrafish Mauthner cell model of axonal injury using single-cell electroporation and two-photon axotomy techniques. We found that overexpression of Rab5 in single Mauthner cells promoted marked axonal regeneration and increased the number of intra-axonal transport vesicles. In contrast, treatment of zebrafish larvae with the Rab kinase inhibitor CID-1067700markedly inhibited axonal regeneration in Mauthner cells. We also found that Rab5 activated phosphatidylinositol 3-kinase(PI3K) during axonal repair of Mauthner cells and promoted the recovery of zebrafish locomotor function. Additionally, rapamycin, an inhibitor of the mechanistic target of rapamycin downstream of PI3K, markedly hindered axonal regeneration. These findings suggest that Rab5 promotes the axonal regeneration of injured zebrafish Mauthner cells by activating the PI3K signaling pathway.

关键词： axonal regeneration Mauthner cell nerve regeneration Rab5 zebrafish

Numerical simulation of microstructure and microporosity morphology in directional solidification of aluminum-copper alloys:Effect of copper content and withdrawal rate

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China Foundry 2025年第1期22卷 33-44页

作者： Wei Yuan Hai-dong Zhao Xu shen Chun Zou Yuan Liu Qing-yan Xu National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China Key Laboratory for Advanced Materials Processing Technology(Ministry of Education) Tsinghua UniversityBeijing 100084China

Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity formation in Al-Cu alloys,considering variations in Cu content and solidification *** results indicate that the Cu content primarily influences the growth of *** validate the model,directional solidification experiments were conducted on Al-Cu alloys with varing Cu contents and withdrawal *** experimental results of dendrites and microporosity characteristics agree well with the predictions from the developed model,thus confirming the validity of the *** alloy’s liquidus temperature,dendrite morphology,and hydrogen saturation solubility arising from different Cu contents have significant effects on microporosity *** withdrawal rate primarily affects the nucleation of hydrogen microporosity by altering cooling rates and dendritic growth rates,resulting in different microporosity characteristics.

关键词： microporosity dendrites cellular automaton Al-Cu alloys directional solidification

挪威山地冰川上雪和粒雪中δ^(18)O的解释及对区域气候的指示意义(英文)

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冰川冻土 2001年第3期23卷 258-263页

作者：何元庆沈永平姚檀栋陈拓杨梅学中科院寒区旱区环境与工程所甘肃兰州 730000 University of Manchester 英国 M139PL

Variations of δ 18 O in the snow which accumulates at a Nordic temperate glacier during the winter are not entirely eliminated after a few months of ablation in the following summer. Survive of isotopic signals closely relates to the re\|freezing capacity of snow accumulated in winter when its temperature was below 0 ℃. The melt\|water re\|freezing ice layers formed in winter hindered subsequent melt\|water percolation in summer when snow temperature was at melting point and, therefore, varied isotopic record was reserved between these ice layers. The isotopic record in snow pack can provide an estimate of the approximate trend of the most recent winter season temperatures. The relationship between regional temperature changes and δ 18 O values in the snow pack is affected by many natural factors, but 1989\1990 （a glacier balance year） winter air temperatures were reflected in the snow which remained on the glacier Austre Okstindbreen at an altitude of \{1 350\} m in July 1990. There was larger amplitude of variations of δ 18 O values in the 4.1 m of snow above the 1989 summer surface, but variations in the underlying firn were relatively small. Melt water percolation modifies the initial variations of δ 18 O values in the snow pack. At a site below the mean equilibrium line altitude on Austre Okstindbreen, increased isotopic homogenization within a ten\|day period in July accompanied an increase of the mean δ 18 O value. Although the isotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glaciers, it can provide an estimate of the approximate trend of recent local temperature variations.

关键词：挪威冰川雪氧同位素气候变化

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黄河河源区径流对气候变化的敏感性分析

冰川冻土 2010年第1期32卷 175-182页

作者：蓝永超文军赵国辉沈永平胡兴林畅俊杰马建华中国科学院内陆河流域生态水文与流域科学重点实验室甘肃兰州730000 中国科学院寒区旱区环境与工程研究所甘肃兰州730000 黄河水利委员会河源区研究院甘肃兰州730000 甘肃省水文水资源局甘肃兰州730000

利用黄河源区有关水文、气象台站观测资料,对河源区各分区气候变化特征及各分区径流深对气候变化的敏感性进行了分析.结果表明:有器测资料以来的近50a间,河源区气温与全球变暖有着较好的对应关系,各区平均气温均呈不同程度的波动上升态... 详细信息

利用黄河源区有关水文、气象台站观测资料,对河源区各分区气候变化特征及各分区径流深对气候变化的敏感性进行了分析.结果表明:有器测资料以来的近50a间,河源区气温与全球变暖有着较好的对应关系,各区平均气温均呈不同程度的波动上升态势;而降水量的变化比较复杂,区域性差异较大;河源区径流的变化与降水量、气温的变化之间存在较显著的非线性关系.由于气温的持续上升与主要产流区降水的持续减少,区域径流量呈持续减少的趋势.总体上,河源区各分区径流对降水变化的敏感程度要强于气温,但吉迈以上区域径流对气温变化的敏感性要强于其下游其它两个区域.

关键词：黄河河源区径流深降水量气温全球变暖

塔里木河干流上游中、下段河床淤积和耗水对生态环境的影响

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冰川冻土 2009年第6期31卷 1086-1093页

作者：王进龚伟华沈永平高前兆王顺德阿克苏水文水资源勘测局新疆阿克苏843000 中国科学院寒区旱区环境与工程研究所甘肃兰州730000

塔里木河干流上游中、下段河床一直呈淤积状态,新渠满站1965-2007年总淤积厚度达120cm,平均年淤积3.0cm.其中:1965-1990年25a淤积50cm,年均淤积2.0cm,1991-2007年17a中河床淤积加快,总淤积70cm,年均淤积4.7cm.由于河床淤积,河道行洪断... 详细信息

塔里木河干流上游中、下段河床一直呈淤积状态,新渠满站1965-2007年总淤积厚度达120cm,平均年淤积3.0cm.其中:1965-1990年25a淤积50cm,年均淤积2.0cm,1991-2007年17a中河床淤积加快,总淤积70cm,年均淤积4.7cm.由于河床淤积,河道行洪断面缩水,洪水漫溢不断增大,导致上游段耗水量呈不断增加趋势,2001年起上游段己成为干流最大的耗水区.阿克苏河、和田河和叶尔羌河3条源流出山口多年平均年输沙量为6310×104t,进入塔里木河干流龙头站——阿拉尔站多年平均年输沙量为2050×104t,干流上游段多年平均年泥沙淤积量为1462×104t,占塔里木河阿拉尔站多年平均年输沙量的71.3%,是干流最大的泥沙淤积区,也是现今最大的洪水漫溢区和耗水区.塔里木河干流上、中、下游各水文点年输沙量呈急剧減少趋势,泥沙淤积河道主要是上游段的沙雅二牧场至英巴扎318km河段.塔里木河上游段河长495km,多年平均区间耗水量14.48×108m3,占阿拉尔站多年径流量的31.5%;中游河长398km,多年平均区间耗水量24.84×108m3,占阿拉尔站年径流量的54.0%;下游河长428km,多年平均区耗水量6.68×108m3,占阿拉尔站年径流量的14.5%.上、中游段多年平均区间耗水量39.32×108m3,占阿拉尔站年径流量的85.5%.上游耗水量从2001年起成为塔里木河干流最大的耗水区,导致2002、2005和2006年上、中游耗水量达到50.0×108m3,占阿拉尔站年径流量的88%,成为历史最大值.

关键词：塔里木河干流上游中下段河床淤积加快耗水呈增加趋势生态环境

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新疆天山南麓柯坪河水文特性与洪水分析

冰川冻土 2007年第5期29卷 824-829页

作者：严宇红沈永平李宇安王国亚王顺德新疆维吾尔自治区水文水资源局新疆乌鲁木齐830000 中国科学院寒区旱区环境与工程研究所甘肃兰州730000 新疆维吾尔自治区阿克苏水文水资源勘测局新疆阿克苏843000

柯坪河是天山南麓典型的雨水和泉水补给河流,河水主要为地下泉水出露补给,流量比较稳定,但暴雨的出现经常引起洪水发生.柯坪河仅有不足一年的水文观测,但河水主要是泉水补给,水量非常稳定,根据野外调查和推算,分析了柯坪河年内水文变化... 详细信息

柯坪河是天山南麓典型的雨水和泉水补给河流,河水主要为地下泉水出露补给,流量比较稳定,但暴雨的出现经常引起洪水发生.柯坪河仅有不足一年的水文观测,但河水主要是泉水补给,水量非常稳定,根据野外调查和推算,分析了柯坪河年内水文变化特征.依据洪水调查和文献查证,结合气象观测资料,分析了近百年来的典型洪水事件,建立了不同几率洪水发生的洪峰流量和洪水过程.最近几十年来的气温升高和降水增加,也使暴雨洪水的强度加强,并且频次增加.应加强对极端气候事件引发的洪水的监测和应对,在农业和水库安全运营上应注意和加强建立应对气候变化的措施.

关键词：柯坪河泉水补给暴雨洪水气候变化

1961—2017年东帕米尔高原极端升温过程气候变化特征

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干旱区研究 2019年第6期36卷 1368-1378页

作者：毛炜峄姚俊强陈静李淑娟李红军沈永平中国气象局乌鲁木齐沙漠气象研究所中亚大气科学研究中心中国科学院西北生态环境资源研究院

利用塔什库尔干、吐尔尕特和乌恰3个气象站1961年1月1日至2017年12月31日的逐日最高气温,建立了中巴经济走廊北端东帕米尔高原单站升温过程数据库,用百分位法基于综合强度指标遴选出极端升温过程,对比分析了该区域塔什库尔干等3站的极... 详细信息

利用塔什库尔干、吐尔尕特和乌恰3个气象站1961年1月1日至2017年12月31日的逐日最高气温,建立了中巴经济走廊北端东帕米尔高原单站升温过程数据库,用百分位法基于综合强度指标遴选出极端升温过程,对比分析了该区域塔什库尔干等3站的极端升温过程频数、强度气候变化特征。结果表明:(1)1961-2017年,东帕米尔高原塔什库尔干共出现489次极端升温过程,平均每年出现8.6次。塔什库尔干极端升温过程平均持续3.6 d,以持续3 d的最多,占24.7%,吐尔尕特和乌恰以持续2~3 d的极端升温过程为主。塔什库尔干的极端升温过程在7月出现最多,吐尔尕特在5月最多,乌恰在1月最多。(2)塔什库尔干综合强度最强的1次升温过程出现在2008年2月20-21日。东帕米尔高原3站的极端升温过程综合强度均在冬季最强。(3)57a来,东帕米尔高原塔什库尔干年极端升温过程频数呈显著的线性增加趋势,增加率为0.57次·(10a)^-1,进入21世纪以来,极端升温过程相对频发,年际间变率加剧。吐尔尕特与乌恰的线性变化趋势不显著。(4)57 a来,塔什库尔干的极端升温过程强度呈显著的线性增强趋势,且近年来年际间变化幅度加剧;乌恰的过程强度略呈下降趋势,近年来年际间变化幅度趋于平缓。总之,塔什库尔干7月的极端升温过程最多,57 a来年极端升温过程频数显著增多、强度显著增强,近年来极端升温过程频数及强度的年际间变化幅度均加剧,造成东帕米尔高原区域融冰(雪)洪水及其衍生地质灾害频发,风险加剧。

关键词：极端升温过程频数强度气候变化帕米尔高原