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Science China Chemistry 2022年第1期65卷 7-19页

作者： Jiangyan wang Zumin wang dan Mao dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Hollow multishelled structure(HoMS)is one of the most promising multifunctional *** high complexity of its structure makes the general and controllable synthesis of HoMS rather *** integration of multidisciplinary knowledge,a great achievement in HoMSs has been obtained in the past ***,the developed sequential templating approach has significantly boomed the progress of HoMS in composition and structure diversity and application *** implementation of the temporal-spatial ordering in HoMS makes it indispensable in solving the key scientific problems in energy conversion,catalysis and drug delivery *** development in HoMSs with novel intricate structures will bring new *** this review,we systematically introduce the development history of HoMSs,summarize the inspiration inherited from the previous research on hollow structures,and discuss the milestones in the development of HoMSs,with a focus on the sequential templating approach for HoMS fabrication,attractive temporal-spatial ordering property and dynamic smart behavior for advanced *** hope to reveal the inherent relationship between the precise synthesis of HoMS and its highly tunable compositional and structural characteristics,and point out its future direction to boost HoMS area further.

关键词： hollow multishelled structure sequential templating approach temporal-spatial ordering smart dynamic behavior

H∞-Based Selective Inversion of Nonminimum-phase Systems for Feedback Controls

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 702-710页

作者： dan wang Xu Chen Department of Mechanical Engineering University of WashingtonSeattleWA 98195 USA IEEE

Stably inverting a dynamic system model is fundamental to subsequent servo designs. Current inversion techniques have provided effective model matching for feedforward ***, when the inverse models are to be implemented in feedback systems, additional considerations are demanded for assuring causality, robustness, and stability under closed-loop constraints. To bridge the gap between accurate model approximations and robust feedback performances, this paper provides a new treatment of unstable zeros in inverse design. We provide first an intuitive pole-zero-map-based inverse tuning to verify the basic principle of the unstable-zero treatment. From there, for general nonminimum-phase and unstable systems, we propose an optimal inversion algorithm that can attain model accuracy at the frequency regions of interest while constraining noise amplification elsewhere to guarantee system robustness. Along the way, we also provide a modern review of model inversion techniques. The proposed algorithm is validated on motion control systems and complex high-order systems.

关键词： H∞formulation model inversion nonminimum-phase zeros unstable systems

Shock wave configurations and reflection hysteresis outside a planar Laval nozzle

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Chinese Journal of Aeronautics 2015年第5期28卷 1362-1371页

作者： wang dan Yu Yong School of Aerospace Engineering Beijing Institute of Technology

When the pressure ratio increases from the perfectly expanded condition to the third limited condition in which a normal shock is located on the exit plane, shock wave configurations outside the nozzle can be further assorted as no shock wave on the perfectly expanded condition, weak oblique shock reflection in the regular reflection （RR） pressure ratio condition, shock reflection hysteresis in the dual-solution domain of pressure ratio condition, Mach disk configurations in the Mach reflection （MR） pressure ratio condition, the strong oblique shock wave configurations in the corresponding condition, and a normal shock forms on the exit plane in the third limited con- dition. Every critical pressure ratio, especially under regular reflection and Mach reflection pressure ratio conditions, is deduced in the paper according to shock wave reflection theory. A hysteresis phenomenon is also theoretically possible in the dual-solution domain. For a planar Laval nozzle with the cross-section area ratio being 5, different critical pressure ratios are counted in these con- ditions, and numerical simulations are made to demonstrate these various shock wave configurations outside the nozzle. Theoretical analysis and numerical simulations are made to get a more detailed understanding about the shock wave structures outside a Laval nozzle and the RR←→MR transition in the dual-solution domain.

关键词： Critical pressure ratios Hysteresis Mach reflection Regular reflection Shock wave configurations

Tunable valley band and exciton splitting by interlayer orbital hybridization

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npj Computational Materials 2022年第1期8卷 2291-2299页

作者： dan wang Xiaolong Zou Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen518055China

Magnetic proximity effect has been demonstrated to be an effective routine to introduce valley splitting in two-dimensional van der Waals ***,the control of its strength and the induced valley splitting remains *** this work,taking heterobilayers combining monolayer MSe_(2)(M=Mo or W)with room-temperature ferromagnetic VSe_(2)as examples,we demonstrate that the valley splitting for both band edges and excitons can be modulated by the tuning of the interlayer orbital hybridization,achieved by inclusion of different amounts of exact Hartree exchange potential via hybrid ***,we show such tuning of orbital hybridization could be experimentally realized by external strain and electric *** calculations suggest that large valley band splitting about 30 meV and valley exciton splitting over 150 meV can be induced in monolayer MSe_(2).Our work reveals a way to control proximity effects and provides some guidance for the design of optoelectronic and valleytronic devices.

关键词： field splitting orbital

Spatial Structure and Location of Multi-national Corporations in China—A Case Study of Samsung

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Chinese Geographical Science 2007年第4期17卷 297-303页

作者： wang dan wang Shijun School of Resources and Environmental Science East China Normal University Shanghai 200062 China Department of Geography Shanghai Normal University Shanghai 200234 China College of Urban and Environmental Science Northeast Normal University Changchun 130024 China

The investment of Samsung Electronics in China is divided into three types： production companies, sales companies and R＆D institutions. Based on an analysis of the spatial structure of Samsung＇s three types of investment and parent company, it is put forward that regional bias exists during the operation of a multi-national corporation （MNC） in China, i.e., regional biases of technology, price, sales as well as decision-making. Front office and back ofrice, two terms related closely with the location of modern MNCs, are defined and locational principles of each are studied. It is pointed out that production companies and R＆D institutions belong to back office, while sales company falls into the type of front office. Based on a summarization on the spatial distribution of production companies, sales companies and R＆D institutions, the locational principles of front office and back office are then applied in explaining the location of Samsung＇s operating entities in China. By analyzing the spatial structure and locational principles of Samsung, a typical MNC in China, this paper aims to understand the internal operating mechanism of modern MNCs and then bring assistance to related policies to cope with those problems about MNCs that have attracted growing attention in recent years.

关键词： multi-national corporation (MNC) regional bias front office back office Samsung

Effect of crystalline grain structures on the mechanical properties of twinning-induced plasticity steel

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Acta Mechanica Sinica 2016年第1期32卷 181-187页

作者： Kun wang dan wang Fusheng Han Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences

In order to improve the mechanical properties of twinning-induced plasticity steel, the grain morphology was tailored by different solidification technologies combined with deformation and heat treatment processing routes. Three typical grain morphologies, i.e., equiaxed, columnar as well as equiaxed/columnar grains were formed, and their mechan- ical behaviors were comparatively studied. Among the three materials, the equiaxed grain material exhibited the highest strength but the lowest plasticity. Depending on the grain size, the smaller the grain size, the higher the strength, but the lower the elongation. The columnar grain material pos- sessed the most excellent plasticity but the weakest strength. These properties presented a non-monotonic dependence on the dendrite spacing, and the moderate spacing resulted in the optimum combination of strength and plasticity. The equiaxed/columnar grain coexisted material showed inter- esting properties, i.e., the strength and plasticity were just between those of single grain-shaped materials. The three materials also presented different strain hardening behaviors particularly in the uniform deformation stage. The equiaxed grain material showed a constant strain hardening rate, while the columnar grain and equiaxed/columnar grain materials showed a progressively increasing rate with increasing the true strain.

关键词： TWIP steel Twins Crystalline grainstructures Mechanical properties

Constructing BaTiO_(3)/TiO_(2)@polypyrrole composites with hollow multishelled structure for enhanced electromagnetic wave absorbing properties

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International Journal of Minerals,Metallurgy and Materials 2023年第3期30卷 581-590页

作者： dan Mao Zhen Zhang Mei Yang Zumin wang Ranbo Yu dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Department of Energy Storage Science and Engineering School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing 100083China University of Chinese Academy of Sciences Beijing 100049China

BaTiO_(3)/TiO_(2)@polypyrrole(PPy)composites with hollow multishelled structure(HoMS)were constructed to enhance the electromagnetic wave absorbing properties of BaTiO_(3)-based absorbing ***_(3)/TiO_(2)HoMSs were prepared by hydrothermal crystallization using TiO_(2)Ho MSs as ***,FeCl3 was introduced to initiate the oxidative polymerization of pyrrole monomer,forming BaTiO_(3)/TiO_(2)@PPy HoMSs *** electromagnetic wave absorbing properties of BaTiO_(3)/TiO_(2)HoMSs and BaTiO_(3)/TiO_(2)@PPy Ho MSs with different shell number were investigated using a vector network *** results indicate that BaTiO_(3)/TiO_(2)@PPy HoMSs exhibit improved microwave absorption compared with BaTiO_(3)/TiO_(2)*** particular,tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS has the most excellent absorbing *** best reflection loss can reach up to-21.80 dB at 13.34 GHz with a corresponding absorber thickness of only 1.3 mm,and the qualified absorption bandwidth of tripled-shelled BaTiO_(3)/TiO_(2)@PPy HoMS is up to 4.2 *** work paves a new way for the development of high-performance composite microwave absorbing materials.

关键词： BaTiO_(3)/TiO_(2)@polypyrrole composites hollow multishelled structure electromagnetic wave absorbing

小肠黏膜下层脱细胞基质复合外泌体构建组织工程尿道

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中国组织工程研究 2025年第23期29卷 4907-4914页

作者：王丹朱小军李志成李娜内蒙古医科大学附属医院泌尿外科内蒙古自治区呼和浩特市010050

背景:小肠黏膜下层脱细胞基质已被临床与基础研究证实可用于尿道的修复重建,但其单独应用时存在宿主细胞生长缓慢、支架血管化不足而成活困难、重建尿道狭窄梗阻等问题,仅适用于较短的尿道狭窄。目的:探讨应用小肠黏膜下层脱细胞基质复... 详细信息

背景:小肠黏膜下层脱细胞基质已被临床与基础研究证实可用于尿道的修复重建,但其单独应用时存在宿主细胞生长缓慢、支架血管化不足而成活困难、重建尿道狭窄梗阻等问题,仅适用于较短的尿道狭窄。目的:探讨应用小肠黏膜下层脱细胞基质复合外泌体构建组织工程尿道的可行性。方法:从新西兰大白兔骨髓间充质干细胞中分离提取外泌体;制备猪小肠黏膜下层脱细胞基质,将外泌体负载于小肠黏膜下层脱细胞基质上。将小肠黏膜下层脱细胞基质-外泌体(PKH26染料标记)复合物与脐静脉内皮细胞共培养12 h,观察细胞摄取外泌体情况。选取生长状态良好的脐静脉内皮细胞,分3组培养:空白组常规培养,对照组加入小肠黏膜下层脱细胞基质,实验组加入小肠黏膜下层脱细胞基质-外泌体复合物,通过划痕实验、成管实验、血管生成因子分泌检测评估血管生成情况。取30只新西兰大白兔,建立长段(3 cm)尿道缺损模型,采用随机数字表法分3组干预(n=10):单独材料组植入小肠黏膜下层脱细胞基质,对照组植入小肠黏膜下层脱细胞基质-骨髓间充质干细胞复合物,实验组植入小肠黏膜下层脱细胞基质-外泌体复合物,植入后12周进行尿道造影、尿动力学检查及重建尿道切片病理观察。结果与结论:(1)荧光显微镜下可见小肠黏膜下层脱细胞基质中的外泌体可被脐静脉内皮细胞摄取。(2)与空白组、对照组相比,实验组材料可促进脐静脉内皮细胞的迁移、成血管能力以及成血管因子血管内皮生长因子、肝细胞生长因子、白细胞介素8的分泌(P <0.05)。(3)尿道造影结果显示,单独材料组10只兔均出现尿道狭窄,对照组10只兔中2只出现尿道狭窄,实验组10只兔均未出现尿道狭窄。尿动力检查结果显示,单独材料组兔材料植入后12周的最大尿道压高于术前(P <0.05),对照组、实验组兔植入后12周的最大尿道压均低于空白组(P <0.05)。苏木精-伊红、Masson与免疫组化染色显示,单独材料组可见明显的再生上皮层、少量的皮下平滑肌与血管,以纤维组织增生为主,伴有明显炎性细胞浸润;对照组可见较完整的再生上皮与少量胶原,可见大量的皮下血管与平滑肌,伴有炎性细胞浸润;实验组可见完整的再生上皮层与大量的皮下血管、平滑肌,未见明显炎性细胞浸润,实验组AE1/AE3、ɑ-平滑肌肌动蛋白、CD31阳性表达均高于单独材料组、对照组(P <0.05)。(4)结果表明,小肠黏膜下层脱细胞基质-外泌体组织工程尿道可通过促进血管生成来修复尿道缺损。

关键词：尿道损伤尿道狭窄小肠黏膜下层脱细胞基质细胞外基质外泌体组织工程尿道

Spatial Structure of Central Places in Jilin Central Urban Agglomeration, Jilin Province, China

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Chinese Geographical Science 2014年第3期24卷 375-383页

作者： wang Shijun wang Yongchao wang dan School of Geographical Science Northeast Normal University Shanghai Normal University

Using the radius of gyration from fractal theory, this paper describes the calculation of fractal dimensions for the four tiers of central places in the Jilin Central Urban Agglomeration(JCUA), Jilin Province, China and the structural characteristics of each tier: 1) the 1st tier central place, Changchun Proper(not including Shuangyang District), provides the most service functions and has the most stable primate position; 2) the 2nd tier central places, Jilin Proper, Siping Proper, Liaoyuan Proper and Songyuan Proper have unclear statuses and do not provide certain functions; 3) the 3rd tier central places comprise 23 county-level cities, counties and urban districts(including Shuangyang District of Changchun), exhibiting a dense spatial structure that agrees with theory; 4) the 4th tier contains the largest number of central places(248 designated towns), but they are loosely distributed. In this study, a spatial image of the JCUA was created, based on vectorized data of the urban settlement distribution, which was then modified and abstracted to create a hexagonal network covering the JCUA. Compared to the traditional central place model, the modified spatial image conforms to the K = 3 principle. In reality, however, the growth of some 3rd tier central places should be increased with the cities being upgraded to the 2nd tier so as to overcome that tier′s functional deficiency. The loose distribution in the 4th tier should also be changed. This apparent anomaly can be explained by the fact that the classic hexagon model used to describe the way market areas layout does not exist in the real world. However, this should not be viewed as an obstacle to using central place theory. If its assumptions are properly applied, it can still assist research into the spatial structure of regions.

关键词： Jilin Central Urban Agglomeration (JCUA) central place system spatial structure fractal spatial image

Progress and Perspectives of Hollow Multishelled Structures

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Chinese Journal of Chemistry 2022年第10期40卷 1190-1203页

作者： Jiangyan wang Mei Yang dan wang State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Hollow multishelled structure(HoMs)has drawn tremendous attention due to its abundant attractive properties and promising ***,for a long time,the limited synthesis method hindered the development of *** sequential templating approach developed by our group,has greatly enriched its composition and'structure *** progress in HoMS synthesis promotes the discovery of its characteristics as well as widens its application ***,the recently explored temporal-spatial ordering characteristic of HoMS has shown great promise in drug delivery and cascade catalysis application ***,we summarize the current development progress of HoMS in the aspects of both synthesis and application,with a focus discussion on how to shape its application performance by manipulating its composition and structure *** addition,we discuss the current challenges and providethe future potentials holdingfor HoMs.

关键词： Hollow multishelled structure Sequential templating approach Temporal-spatial ordering Catalysis Structure-activity relationships