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| 1 | Analysis and design for the second order nonlinear continuous extended states observer显示文摘The extended state observer (ESO) is a novel observer for a class of uncertain systems. Since ESO adopts the continuous non-smooth structure, the classical observer design theory is hard to use for ESO analysis. In this note, the self-stable region (SSR) approach, which is a nonlinear synthesis method for nonlinear uncertain systems, will be used for ESO design and its stability analysis. The advantages of the non-smooth structure in ESO for improving the convergence properties and the estimation precision will be shown. | Yi Huang Jingqing Han | 2000 | Chinese Science Bulletin2000,45,21: | 65 |
| 2 | A NEW METHOD FOR STRUCTURAL TOPOLOGICAL OPTIMIZATION BASED ON THE CONCEPT OF INDEPENDENT CONTINUOUS VARIABLES AND SMOOTH MODEL显示文摘A concept of the independent-continuous topological variable is pro-posed to establish its corresponding smooth model of structural topological optimiza-tion. The method can overcome difficulties that are encountered in conventionalmodels and algorithms for the optimization of the structural topology. Its appli-cation to truss topological optimization with stress and displacement constraints issatisfactory, with convergence faster than that of sectional optimizations. | 隋允康 杨德庆 | 1998 | Acta Mechanica Sinica1998,14,2: | 78 |
| 3 | 基于SfM方法的高密度点云数据生成及精度分析显示文摘地形数据的质量(精度和分辨率)影响着地球科学的研究水平。Li DAR测量是目前获取高分辨率地形数据的有效技术方法之一,但是其高昂的测量成本和相对复杂的后期数据处理限制了Li DAR技术的大众化应用。近年来,一种被称为Sf M(Structure from Motion)的适合大众化使用的新的高精度3维地形数据获取技术开始引起人们的注意。这种新型数字摄影测量技术可以利用高效的图像特征匹配算法从多视角照片中提取重叠区域的3维地形数据。由于Sf M技术仅需要目标物体的照片,而且对相机拍摄位置、图像尺度及拍摄焦距没有要求,因此利用简单测量平台采集地面照片就可以获取高质量的3维地形数据。与Li DAR技术相比,大大降低了获取高精度数据的成本,使得高精度3维地形数据的使用大众化。文中介绍了Sf M技术的基本原理和流程,展示了Sf M技术获取高精度3维地形数据的简单而有效的特性,特别适合于植被稀少的区域。文中利用近千米高空拍摄的、具有约70%重叠度的一套随Li DAR飞行采集的数字航空照片生成具有真彩色的高密度Sf M点云数据,点密度高达25.5个/m2,可生成分辨率0.2m的DEM(数字高程模型)。对比相同区域的LiDAR点云数据,统计分析表明58.3%的Li DAR数据与Sf M数据的垂直偏差<0.1m,88.3%的Li DAR数据的垂直偏差<0.2m;而且发现不同地貌的Sf M数据精度存在差异,平缓地形的Sf M数据精度高于陡峭地形的Sf M数据精度。文中还介绍了以氦气球作为拍摄平台的Sf M测量系统,可以快捷地获取高精度的3D地形数据和正射影像,比目前常用的差分GPS测量具有更高的效率和数据精度。 | 魏占玉 Arrowsmith Ramon 何宏林 高伟 | 2015 | 地震地质2015,37,2: | 71 |
| 4 | 大兴安岭地区德尔布干断裂带北段构造年代学研究显示文摘德尔布干断裂带是大兴安岭隆起西侧NE向的重要断裂带,处在海拉尔-拉布达林-根河盆地西缘,是著名德尔布干成矿区东南边界断裂带。为了确定德尔布干断裂带运动性质、活动时间,深入探讨该断裂带与中生代海拉尔-拉布达林-根河盆地及大兴安岭盆山格局、认识德尔布干断裂带多金属矿床成因等问题,本文应用锆石SHRIMP和云母^(40)At/^(39)Ar定年技术,分别对断裂带内的细粒黑云母花岗岩侵入体、韧性变形的花岗闪长质片麻岩、白云母石英片岩,进行了同位素年代学研究。其中花岗闪长质片麻岩岩浆型锆石SHRIMP谐和年龄300.6±9.3Ma,为花岗闪长质片麻岩海西期的侵位年龄;而花岗闪长质片麻岩中黑云母^(40)At/^(39)Ar坪年龄是130.9±1.4Ma,白云母石英片岩的白云母^(40)Ar/^(39)Ar坪年龄是115.6±1.6Ma,代表早白垩世伸展构造变形年龄;细粒黑云母花岗岩侵入体岩浆型锆石SHRIMP谐和年龄130.1±1.4Ma,为同伸展构造变形侵位的岩浆事件。上述地质年代说明德尔布干断裂带是早白垩世(110~130Ma)该区最年轻的重大伸展构造变形产物。控制NE向大兴安岭隆起和中生代海拉尔-拉布达林-根河等火山沉积盆地的发育格局、以及中生代以来的地壳演化与成矿类型。 | 郑常青 周建波 金巍 季建清 张兴洲 马志红 丁雪 | 2009 | 岩石学报2009,25,8: | 42 |
| 5 | 阿尔金淡水泉早古生代泥质高压麻粒岩及其P-T演化轨迹显示文摘南阿尔金构造带淡水泉一带出露的含石榴石蓝晶石黑云母片麻岩是一套典型的泥质高压麻粒岩,其峰期特征矿物组合为石榴子石+蓝晶石+钾长石+金红石+石英。根据矿物内部一致性热力学数据和Thermocalc 3.23程序计算,确定其峰期变质温压条件为T>850℃和P>11kbar。结合岩相学研究和P-T视剖面图计算,可识别出该岩石经历了4个阶段的变质演化,构成了一个早期快速等温降压,后期近等压降温的顺时针型的退变质P-T演化轨迹,为与陆壳俯冲碰撞有关的高压变质事件的产物。该岩石锆石阴极发光图像显示其内部具有明显的核-边结构,核部为残留的原岩碎屑锆石,边部则表现为面状或扇状生长的变质锆石的特征。微区原位LA-ICP-Ms微量元素分析表明,核部测点的重稀土含量较高,对应Th/U接近于0.4,具有岩浆锆石的特征;边部测点的重稀土相对亏损,重稀土配分曲线平坦,对应Th/U比值均小于0.1,显示与石榴子石平衡共生的变质锆石特征。LA-ICP-MS微区定年获得其变质年龄为486±5Ma,该年龄值与阿尔金江尕勒萨依和英格利萨依两地超高压变质岩石的变质年龄相近,进一步证明沿阿尔金构造带南缘断续存在一条早古生代的高压-超高压变质岩带。另外,本次研究在获得该泥质高压麻粒岩峰期变质时代的同时,还获得该岩石原岩的形成时代上限值约为719Ma,从而限定阿尔金构造带南缘阿尔金群的形成时代可能不属古元古代,而应属新元古代。 | 曹玉亭 刘良 王超 陈丹玲 张安达 | 2009 | 岩石学报2009,25,9: | 35 |
| 6 | Bioactive flavonoids in medicinal plants:Structure, activity and biological fate显示文摘Flavonoids, a class of polyphenol secondary metabolites, are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, antiinflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Their basic structures consist of C_6—C_3—C_6 rings with different substitution patterns to produce a series of subclass compounds, and correlations between chemical structures and bioactivities have been studied before. Given their poor bioavailability, however, information about associations between structure and biological fate is limited and urgently needed. This review therefore attempts to bring some order into relationships between structure, activity as well as pharmacokinetics of bioactive flavonoids. | Tian-yang Wang Qing Li Kai-shun Bi | 2018 | Asian Journal of Pharmaceutical Sciences2018,13,1: | 36 |
| 7 | Chinese Economic Structure and SDA Model | CHEN Xi\|kang 1,\ GUO Ju\|e 2 1. Academy of Machemation and Systems Science, Chinese Academy of Science Beijing 100080, China 2. Shaanxi Institute of Finance and Economics, Xi′an 710061, China | 2000 | Systems Science and Systems Engineering2000,10,2: | 40 |
| 8 | 谣言实现的社会机制及对信息的治理显示文摘Rumors are a type of false information, a consequence of an asymmetrical informational structure. This paper focuses on the social mechanisms of rumor fulfilling. Rumors with important contents related to people’s personal interests win acceptance through changing people’s expected payoffs, misleading people to the belief that acceptance of the rumor would beneficially outperform rejection of it. Nevertheless, it is risky to believe rumors; therefore, people make their decision whether to believe a rumor or not by referring to other people’s choices. An analysis was performed first within a game model that incorporated the variables of an individual’s expectancy and other people’s impact to predict whether the individual would accept or reject a rumor. Another analysis followed to further examine the functions of some dynamic mechanisms in rumor fulfilling when group pressure and network effects were introduced. Finally, an exploratory discussion on how to prevent rumors and erase their effects via information management strategies was presented. | 李国武 | 2005 | 社会2005,25,4: | 31 |
| 9 | The effect of land use structure on the distribution of soil nutrients in the hilly area of the Loess Plateau,China显示文摘The irrational land use is one of the main reasons for the soil erosion and nutrient loss in the loess hilly area of China. In this project, 4 types of typical land use structure of sustain ment for about 15 years in the loess hill slope are selected to study the effect of land use structure on the distribution of soil nutrients. From hill bottom to hill top, the patterns of land use types are:, grassland-slope farmland-forest, slope farmland-grassland-forest, terrace-grassland-forest and slope farmland-forest-grassland. By measuring the contents of the total N, total P, available N, available P and organic matter of soils, the results show that the land use structure types of slope farmland-grassland-forest and terrace-grassland-forest have a better capacity to maintain the soil nutrients. | Bojie Fu Keming Ma Huafeng Zhou Liding Chen | 1999 | Chinese Science Bulletin1999,44,8: | 32 |
| 10 | Structural characteristics of the Tan-Lu fault zone in Cenozoic basins offshore the Bohai Sea显示文摘The Tan-Lu fault zone across the eastern margin of the Cenozoic basins offshore the Bohai Sea is a NNE-trending right-lateral strike-slip fault system developed in the Cenozoic basin cover. It cuts through NE-to NNE-striking major extensional faults that controlled the formation of Paleogene basins. Recent petroleum exploration indicates that Cenozoic structural activities of the Tan-Lu fault system have directly or indirectly affected oil and gas distribution offshore the Bohai Sea. As part of a deep fault zone the Tan-Lu fault zone has been activated since the Oligocene,and obviously affected the tectonic evolution of offshore Bohai basins since then. The formation of Paleogene rift basins offshore the Bohai Sea has utilized the pre-existing structural elements of the Tan-Lu fault zone that developed in the late Mesozoic. | QI JiaFu1,2,ZHOU XinHuai3,DENG RongJing4 & ZHANG KeXin2 1 State Key Laboratory of Petroleum Resource and Prospecting,China Petroleum University,Beijing 102249,China 2 Department of Earth Sciences,China Petroleum University,Beijing 102200,China 3 Tianjin Branch of CNOOC China Limited,Tianjin 300451,China 4 Beijing Research Center of CNOOC China Limited,Beijing100027,China | 2008 | Science China Earth Sciences2008,51,S2: | 33 |
| 11 | Synthesis of core-shell acrylic-polyurethane hybrid latex as binder of aqueous pigment inks for digital inkjet printing | Jingfang Zhang a,Xuefeng Li a,Xinhao Shi a,Mei Hua a,Xingping Zhou b,Xiaqin Wang a,a State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University,Shanghai 201620,China b College of Chemical Engineering and Biotechnology,Donghua University,Shanghai 201620,China | 2012 | Progress in Natural Science:Materials International2012,22,1: | 31 |
| 12 | Review on hidden trouble detection and health diagnosis of hydraulic concrete structures显示文摘A large number of hydraulic concrete structures have hidden defects such as cracks, erosion, freeze and thaw, thermal fatigue, carbonization. These hidden defects seriously affect the strength, stability and durability of structures. These problems are studied mainly by single monitoring or diagnosis methods at present. The integration of multiple monitoring and diagnosis methods is not applied widely. Besides, the analysis theory on these problems is not developed very well. The systemic study on the aging mechanism of hydraulic concrete structures, time- variation model and health diagnosis is still not enough. The support for engineering practice is limited. Aimed at these major scientific and technological problems and combined with specific projects, study on detection of hidden defects and health diagnosis of hydraulic concrete structure has been carried out. This study includes the following content: field non-destructive examination of hidden defects of hydraulic concrete structures, seepage detection, the construction of in-situ sensing system, the combination of field detection and in-situ monitoring, the mechanism of crack, freeze and thaw, erosion and carbonization of hydraulic concrete structure, mechanism of combination aging; time-variation model of hydraulic concrete structure, theories and methods for health diagnosis of hydraulic concrete structures. | WU ZhongRu1,2?, LI Ji1, GU ChongShi1,2 & SU HuaiZhi1,2 1 College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China 2 National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing 210098, China | 2007 | Science China(Technological Sciences)2007,50,z1: | 27 |
| 13 | SfM摄影测量方法在活动构造定量研究中的应用显示文摘高精度、高分辨率的地形地貌数据是活动构造定量研究的基础。摄影测量方法的出现和快速发展为获取高精度地形地貌数据提供了一种经济有效的技术手段。相比于传统的测量方法,摄影测量方法可在大范围内同时进行,不受地面通视条件的限制,且测量成本相对较低。尤其近年来,随着计算机视觉理论及高效的自动特征匹配算法的发展,一种名为'Structure from Motion'(SfM)的三维重建技术被引入摄影测量方法中,极大地提高了摄影测量的自动化程度。文中介绍了摄影测量方法的基本原理及发展历程,并综述了摄影测量方法在活动构造研究中的应用,最后通过SfM摄影测量方法在活动构造研究中的1个具体应用实例,展示了摄影测量方法在活动构造定量研究中的巨大应用潜力。 | 毕海芸 郑文俊 曾江源 俞晶星 任治坤 | 2017 | 地震地质2017,39,4: | 28 |
| 14 | High-entropy ceramics:Present status,challenges,and a look forward显示文摘High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements.Although in the infant stage,the emerging of this new family of materials has brought new opportunities for material design and property tailoring.Distinct from metals,the diversity in crystal structure and electronic structure of ceramics provides huge space for properties tuning through band structure engineering and phonon engineering.Aside from strengthening,hardening,and low thermal conductivity that have already been found in high-entropy alloys,new properties like colossal dielectric constant,super ionic conductivity,severe anisotropic thermal expansion coefficient,strong electromagnetic wave absorption,etc.,have been discovered in HECs.As a response to the rapid development in this nascent field,this article gives a comprehensive review on the structure features,theoretical methods for stability and property prediction,processing routes,novel properties,and prospective applications of HECs.The challenges on processing,characterization,and property predictions are also emphasized.Finally,future directions for new material exploration,novel processing,fundamental understanding,in-depth characterization,and database assessments are given. | Huimin XIANG Yan XING Fu-zhi DAI Hongjie WANG Lei SU Lei MIAO Guojun ZHANG Yiguang WANG Xiwei QI Lei YAO Hailong WANG Biao ZHAO Jianqiang LI Yanchun ZHOU | 2021 | Journal of Advanced Ceramics2021,10,3: | 28 |
| 15 | Structure of the spectrum of infinite dimensional Hamiltonian operators显示文摘This paper deals with the structure of the spectrum of infinite dimensional Hamiltonian operators.It is shown that the spectrum,the union of the point spectrum and residual spectrum,and the continuous spectrum are all symmetric with respect to the imaginary axis of the complex plane. Moreover,it is proved that the residual spectrum does not contain any pair of points symmetric with respect to the imaginary axis;and a complete characterization of the residual spectrum in terms of the point spectrum is then given.As applications of these structure results,we obtain several necessary and sufficient conditions for the residual spectrum of a class of infinite dimensional Hamiltonian operators to be empty. | Alatancang | 2008 | Science China Mathematics2008,51,5: | 26 |
| 16 | Cementing mechanism of algal crusts from desert area显示文摘34-, 17-, 4-, 1.5-year old natural algal crusts were collected from Shapotou Scientific Station of the Chinese Academy of Sciences, 40-day old field and greenhouse artificial algal crusts were in situ developed in the same sandy soil and the same place (37°27’N, 104°57’E). Their different cohesions both against wind force and pressure were measured respectively by a sandy wind-tunnel experiment and a penetrometer. On the basis of these algal crusts, the cementing mechanism was revealed from many subjects and different levels. The results showed that in the indoor artificial crusts with the weakest cohesion bunchy algal filaments were distributed in the surface of the crusts, produced few extracellular polymers (EPS), the binding capacity of the crusts just accomplished by mechanical bundle of algal filaments. For field crusts, most filaments grew toward the deeper layers of algal crusts, secreted much more EPS, and when organic matter content was more than 2.4 times of chlorophyll a, overmuch organic | HU Chunxiang LIU Yongding ZHANG Delu HUANG Zebo B.S.Paulsen | 2002 | Chinese Science Bulletin2002,47,16: | 25 |
| 17 | 再论中产阶级:理论、历史与类型学 兼及一种全球化的视野显示文摘The emergence of the middle class was closely related to the appearance of industrial society and its consequential constant changes in the social structure. Karl Marx and other theorists in the same camp were among the earliest scholars who discussed that topic. For a quite long period of time, the debate was mainly focused on the characteristics of the “new middle class.” The middle class, however, has undergone a categorical transformation from the old to the new middle-class, and furthermore, this transformation itself has signified the transition in social patterns from industrial to post-industrial society as well as economic globalization, both of which have contributed to the growth and global expansion of the middle class, having thus fundamentally renovated the middle class. | 周晓虹 | 2005 | 社会2005,25,4: | 26 |
| 18 | 库车坳陷克拉苏构造带白垩系砂岩埋藏成岩环境的封闭性及其胶结作用分异特征显示文摘以库车坳陷克拉苏构造带白垩系巴什基奇克组为研究层段,分别通过层间泥岩硼元素含量和碳酸盐胶结物流体包体显微测温,对不同成岩期地层流体盐度进行示踪对比。由于自沉积初始至埋藏成岩期碳酸盐胶结阶段,研究层段经历一段较为稳定的构造时期,再加上沉积及构造疏导体系的缺失,地层流体始终缺乏大规模交换与改造,不同成岩场之间水-岩体系在这一阶段呈现出一定的封闭性特征,使得研究层段在碳酸盐胶结期孔隙流体盐度时空分异较好地延续了同沉积期水体盐度的分异规律,这种延续性不仅体现在平面上,也体现在垂向上。研究层段在碳酸盐胶结期后经历了强烈的构造活动,但由于断层的封堵并未对流体介质进行有效的疏导,先期形成的碳酸盐胶结分异规律因而未受到明显干扰,从而呈现出同沉积地层水体盐度时空分异特征造就了埋藏成岩期碳酸盐胶结作用的时空分异规律。 | 韩登林 李忠 韩银学 刘嘉庆 李维锋 李莎澜 | 2009 | 岩石学报2009,25,10: | 24 |
| 19 | 川东北普光气田下三叠统飞仙关组白云岩成因——来自岩石结构与Sr同位素和Sr含量的证据显示文摘研究了川东北普光气田下三叠统飞仙关组白云岩储层的岩石结构Sr的含量和Sr同位素组成,讨论了它的成因,飞仙关组优质储层为成岩期埋藏交代白云化作用的产物,来自岩石结构和Sr同位素和Sr含量的证据包括如下几个方面:(1)与准同生白云岩比较,埋藏白云岩的岩石结构和Sr同位素和Sr含量地球化学特征与前者有显著差别;(2)飞仙关组所有各类碳酸盐岩(或矿物)具有早三叠世海水Sr同位素组成特征,^(87)Sr/^(86)Sr比值变化范围为0.706588~0.708187,覆盖了全球早三叠世海水Sr同位素的变化范围(0.7076~0.7078),平均值0.707656与全球早三叠世平均值(0.707743)基本一致;(3)埋藏白云岩^(87)Sr/^(86)Sr比值变化范围为0.707122~0.707419,平均值0.707421,都略低于全球早三叠世海水Sr同位素变化范围和平均值,但与已报道的川东北早三叠世飞仙关期海水Sr同位素变化范围(0.707330~0.707383)和平均值(0.707350) 都非常接近,说明白云石化流体具有强烈的川东北地区早三叠世飞仙关期海水Sr同位素组成特征;(4)综合岩石结构、Sr同位素和Sr含量地球化学特征,证明飞仙关组白云岩储层为成岩期埋藏交代作用产物,白云石化流体来自地层中高Sr和高盐度的海源地层水。 | 郑荣才 文华国 郑超 罗平 李国军 陈守春 | 2009 | 岩石学报2009,25,10: | 24 |
| 20 | S-wave crustal and upper mantle's velocity structure in the eastern Tibetan Plateau——Deep environment of lower crustal flow显示文摘A teleseismic profile consisting of 26 stations was deployed along 30°N latitude in the eastern Tibetan Plateau. By use of the inversion of P-wave receiver function, the S-wave velocity structures at depth from surface to 80 km beneath the profile have been determined. The inversion results reveal that there is significant lateral variation of the crustal structure between the tectonic blocks on the profile. From Linzhi north of the eastern Himalayan Syntaxis, the crust is gradually thickened in NE direction; the crustal thickness reaches to the maximum value (~72 km) at the Bangong-Nujiang suture, and then decreased to 65 km in the Qiangtang block, to 57―64 km in the Bayan Har block, and to 40―45 km in the Sichuan Basin. The eastern segment of the teleseismic profile (to the east of Batang) coincides geographically with the Zhubalong-Zizhong deep seismic sounding profile carried out in 2000, and the S-wave velocity structure determined from receiver functions is consistent with the P-wave velocity structure obtained by deep seismic sounding in respect of the depths of Moho and major crustal interfaces. In the Qiangtang and the Bayan Har blocks, the lower velocity layer is widespread in the lower crust (at depth of 30―60 km) along the profile, while there is a normal velocity distribution in lower crust in the Sichuan Basin. On an average, the crustal velocity ratio (Poisson ratio) in tectonic blocks on the profile is 1.73 (σ = 0.247) in the Lhasa block, 1.78 (σ = 0.269) in the Banggong-Nujiang suture, 1.80 (σ = 0.275) in the Qiangtang block, 1.86 (σ = 0.294) in the Bayan Har blocks, and 1.77 (σ = 0.265) in the Yangtze block, respectively. The Qiangtang and the Bayan Har blocks are characterized by lower S-wave velocity anomaly in lower crust, complicated Moho transition, and higher crustal Poisson ratio, indicating that there is a hot and weak medium in lower crust. These are considered as the deep environment of lower crustal flow in the eastern Tibetan Plateau. Flowage of the ductile material in lower crust may be attributable to the variation of the gravitational potential energy in upper crust from higher on the plateau to lower off plateau. | Paul SILVER | 2008 | Science China Earth Sciences2008,51,2: | 24 |