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122篇 您的检索式:作者名="Shiqian"
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1Quantitative characterization of reservoir space in the Lower Silurian Longmaxi Shale,southern Sichuan,China显示文摘Based on the drilling data of the Upper Ordovician Wufeng Shale and the Lower Silurian Longmaxi Shale in southern Sichuan Basin,the construction of matrix pores and the development condition of fractures in a marine organic-rich shale are quantitatively evaluated through the establishment of the reservoir petrophysical models and porosity mathematical models.Our studies show that there are four major characteristics of the Longmaxi Shale confirmed by the quantitative characterization:(1)the pore volume of per unit mass is the highest in organic matter,followed in clay minerals,finally in brittle minerals;(2)the porosity of the effective shale reservoir is moderate and equal to that of the Barnett Shale,and the main parts of the shale reservoir spaces are interlayer pores of clay minerals and organic pores;(3)the porosity of the organic-rich shale is closely related to TOC and brittle mineral/clay mineral ratio,and mainly increases with TOC and clay mineral content;(4)fractures are developed in this black shale,and are mainly micro ones and medium-large ones.In the Longmaxi Shale,the fracture density increases from top to bottom,reflecting the characteristics with high brittle mineral content,high Young’s modulus,low Poisson's ratio and high brittleness at its bottom.WANG YuMan DONG DaZhong YANG Hua HE Ling WANG ShiQian HUANG JinLiang PU BoLing WANG ShuFang 2014Science China Earth Sciences2014,57,2:36
2Myeloid-specific targeting of Notch ameliorates murine renal fibrosis via reduced infiltration and activation of bone marrowderived macrophage显示文摘Macrophages play critical roles in renal fibrosis.However,macrophages exhibit ontogenic and functional heterogeneities,and which population of macrophages contributes to renal fibrosis and the underlying mechanisms remain unclear.In this study,we genetically targeted Notch signaling by disrupting the transcription factor recombination signal binding protein-JK(RBP-J),to reveal its role in regulation of macrophages during the unilateral ureteral obstruction(UUO)-induced murine renal fibrosis.Myeloid-specific disruption of RBP-J attenuated renal fibrosis with reduced extracellular matrix deposition and myofibroblast activation,as well as attenuated epithelial-mesenchymal transition,likely owing to the reduced expression of TGF-β.Mean while,RBP-J deletion significantly hampered macrophage infiltration and activation in fibrotic kidney,although their proliferation appeared unaltered.By using macrophage clearance experiment,we found that kidney resident macrophages made negligible contribution,but bone marrow(BM)-derived macrophages played a major role in renal fibrogenesis.Further mechanistic analyses showed that Notch blockade reduced monocyte emigration from BM by down-regulating CCR2 expression.Finally,we found that myeloid-specific Notch activation aggravated renal fibrosis,which was mediated by CCR2^+macrophages infiltration.In summary,our data have unveiled that myeloid-specific targeting of Notch could ameliorate renal fibrosis by regulating BM-derived macrophages recruitment and activation,providing a novel strategy for intervention of this disease.Yali Jiang Yuanyuan Wang Pengfei Ma Dongjie An Junlong Zhao Shiqian Liang Yuchen Ye Yingying Lu Peng Zhang Xiaowei Liu Hua Han Hongyan Qin 2019Protein & Cell2019,10,3:10
3Rational design of three-phase interfaces for electrocatalysis显示文摘Gas-involving electrochemical reactions,like oxygen reduction reaction (ORR),oxygen evolution reaction (OER),and hydrogen evolution reaction (HER),are critical processes for energy-saving,environment-friendly energy conversion and storage technologies which gain increasing attention.The development of according electrocatalysts is key to boost their electrocatalytic performances.Dramatic efforts have been put into the development of advanced electrocatalysts to overcome sluggish kinetics.On the other hand,the electrode interfaces-architecture construction plays an equally important role for practical applications because these imperative electrode reactions generally proceed at triple-phase interfaces of gas,liquid electrolyte,and solid electrocatalyst.A desirable architecture should facilitate the complicate reactions occur at the triple-phase interfaces,which including mass diffusion,surface reaction and electron transfer.In this review,we will summarize some design principles and synthetic strategies for optimizing triple-phase interfaces of gas-involving electrocatalysis systematically,based on the electrode reaction process at the three-phase interfaces.It can be divided into three main optimization directions:exposure of active sites,promotion of mass diffusion and acceleration of electron transfer.Furthermore,we especially highlight several remarkable works with comprehensive optimization about specific energy conversion devices,including metal-air batteries,fuel cells,and water-splitting devices are demonstrated with superb efficiency.In the last section,the perspectives and challenges in the future are proposed.Yuqing Wang Yuqin Zou Li Tao Yanyong Wang Gen Huang Shiqian Du Shuangyin Wang 2019Nano Research2019,12,9:10
41-Neighbour knapsack problem and prospective greedy algorithm of intentional islanding in active distribution network显示文摘A connected and undirected graph model of active distribution networks with considering the function of interconnecting switches is constructed in this paper.Based on this model,the island partition problem of active distribution networks can be described as a 1-neighbour knapsack problem.An effective heuristic algorithm named prospective greedy algorithm is then proposed to solve this problem.Case studies on PG&E 69-bus network show the validity of the proposed model and algorithm.YU YiXin MA ShiQian 2014Science China(Technological Sciences)2014,57,3:9
5Preparation of Tungsten Film and Its Tribological Properties under Boundary Lubrication Conditions显示文摘Tungsten film(W film) is deposited by using the ion beam assisted deposition(IBAD) on the 316 L substrate surface in this experiment. The micro structure and nano-hardness of the film are investigated by scanning electron microscopy(SEM) and nano-indentation tester. The tribological behavior of W film under lubrication by oil with ZDDP and MoDTC is evaluated by a SRV test machine. The tribo-film formed on the worn surfaces is investigated by X-ray photoelectron spectroscopy(XPS) to find out the tribological mechanisms between the W film and the two additional additives. The result shows that the W film lubricated by ZDDP and MoDTC-blended base oil has synergistic effects on the friction reduction property, while the anti-wear property is mainly caused by the hard surface of W film.Li Xingliang Yue Wen Wang Song Li Guolong Zhao Shiqian 2014China Petroleum Processing & Petrochemical Technology2014,16,3:6
6Alternating Direction Method of Multipliers for Sparse Principal Component Analysis显示文摘We consider a convex relaxation of sparse principal component analysisproposed by d' Aspremont et al. (SIAM Rev. 49:434 448, 2007). This convex relax-ation is a nonsmooth semidefinite programming problem in which the ξ1 norm of thedesired matrix is imposed in either the objective function or the constraint to improvethe sparsity of the resulting matrix. The sparse principal component is obtained by arank- one decomposition of the resulting sparse matrix. We propose an alternating di-rection method based on a variable-splitting technique and an augmented I agrangianframework for solving this nonsmooth semidefinite programming problem. In con-trast to the first-order method proposed in d' Aspremont et al. (SIAM Rev. 49:434448, 2007), which solves approximately the dual problem of the original semidefiniteprogramming problem, our method deals with the primal problem directly and solvesit exactly, which guarantees that the resulting matrix is a sparse matrix. A globalconvergence result is established for the proposed method. Numerical results on bothsynthetic problems and the real applications from classification of text data and senatevoting data are reported to demonstrate the efficacy of our method.Shiqian Ma 2013Journal of the Operations Research Society of China2013,1,2:5
7On the effective inversion by imposing a priori information for retrieval of land surface parameters显示文摘The anisotropy of the land surface can be best described by the bidirectional reflectance distribution function (BRDF). As the field of multiangular remote sensing advances, it is increasingly probable that BRDF models can be inverted to estimate the important biological or climatological parameters of the earth surface such as leaf area index and albedo. The state-of-the-art of BRDF is the use of the linear kernel-driven models, mathematically described as the linear combination of the isotropic kernel, volume scattering kernel and geometric optics kernel. The computational stability is characterized by the algebraic operator spectrum of the kernel-matrix and the observation errors. Therefore, the retrieval of the model coefficients is of great importance for computation of the land surface albedos. We first consider the smoothing solution method of the kernel-driven BRDF models for retrieval of land surface albedos. This is known as an ill-posed inverse problem. The ill-posedness arises from that the linear kernel driven BRDF model is usually underdetermined if there are too few looks or poor directional ranges, or the observations are highly dependent. For example, a single angular observation may lead to an under-determined system whose solution is infinite (the null space of the kernel operator contains nonzero vectors) or no solution (the rank of the coefficient matrix is not equal to the augmented matrix). Therefore, some smoothing or regularization technique should be applied to suppress the ill-posedness. So far, least squares error methods with a priori knowledge, QR decomposition method for inversion of the BRDF model and regularization theories for ill-posed inversion were developed. In this paper, we emphasize on imposing a priori information in different spaces. We first propose a gen-eral a priori imposed regularization model problem, and then address two forms of regularization scheme. The first one is a regularized singular value decomposition method, and then we propose a retrieval method in l1 space. We show that the proposed method is suitable for solving land surface parameter retrieval problem if the sampling data are poor. Numerical experiments are also given to show the efficiency of the proposed methods.WANG YanFei MA ShiQian YANG Hua WANG JinDi LI XiaoWen 2009Science China Earth Sciences2009,52,4:4
8Parametric identification of time-varying systems from free vibration using intrinsic chirp component decomposition显示文摘Time-varying systems are applied extensively in practical applications,and their related parameter identification techniques are of great significance for structural health monitoring of time-varying systems.To improve the identification accuracy for time-varying systems,this study puts forward a novel parameter identification approach in the time-frequency domain using intrinsic chirp component decomposition(ICCD).ICCD is a powerful tool for signal decomposition and parameter extraction,with good signal reconstruction capability in a high-noise environment.To maintain good identification effects for the time-varying system in a noisy environment,the proposed method introduces a redundant Fourier model for the non-stationary signal,including instantaneous frequency(IF)and instantaneous amplitude(IA).The accuracy and effectiveness of the proposed approach are demonstrated by a single-degree-of-freedom system with three types of time-varying parameters,as well as an example of a multi-degree-of-freedom system.The effects of different levels of measured noise on the identified results are also discussed in detail.Numerical results show that the proposed method is very effective in tracking the smooth,periodical,and non-smooth variations of time-varying systems over the entire identification time period even when the response signal is contaminated by intense noise.Sha Wei Shiqian Chen Xingjian Dong Zhike Peng Wenming Zhang 2020Acta Mechanica Sinica2020,36,1:3
9Non-stationary signal analysis based on general parameterized time-frequency transform and its application in the feature extraction of a rotary machine显示文摘Peng ZHOU Zhike PENG Shiqian CHEN Yang YANG Wenming ZHANG 2018Frontiers of Mechanical Engineering2018,13,2:3
10Facile synthesis of GO as middle carrier modified flower-like BiOBr and C_(3)N_(4) nanosheets for simultaneous treatment of chromium(Ⅵ)and tetracycline显示文摘A novel GO modified g-C_(3)N_(4) nanosheets/flower-like BiOBr hybrid photocatalyst is fabricated by a facile method.The characterization results reveal that wrinkled GO is deposited between g-C_(3)N_(4) nanosheets and flower-like BiOBr forming a Z-scheme heterojunction.As a mediator,plicate GO plays a positive role in prompting photogene rated electrons transfe rring through its sizeable 2 D/2 D contact surface area.The g-C3 N4/GO/BiOBr hybrid displays a superior photocatalytic ability to g-C_(3)N_(4) and BiOBr in photodegrading tetracycline(TC),whose removal efficiency could reach 96%within 2 h.Besides,g-C_(3)N_(4)/GO/BiOBr composite can reduce Cr(Ⅵ),and simultaneously treat TC and Cr(Ⅵ)combination contaminant under the visible light The g-C_(3)N_(4)/GO/BiOBr ternary composite also exhibits satisfactory stability and reusability after four cycling experiments.Further,a feasible mechanism related to the photocatalytic process of gC_(3)N_(4)/GO/BiOBr is put forward.This study offers a te rnary hybrid photocatalyst with eco-friendliness and hopeful application in water pollution.Liushan Jiang Yu Xie Fan He Yun Ling Jinsheng Zhao Hao Ye Shiqian Li Yang Hou 2021Chinese Chemical Letters2021,32,7:3
11带先验约束的地表参数提取的有效反演方法显示文摘地球表面的各向异性特性可以用地表二向反射函数(BRDF)恰当地描述.BRDF的核心是利用线性核驱动模型,数学上表述为各向同性核、体散射核和几何光学核的线性组合.随着多角度遥感领域的发展,BRDF模型越来越被看作是可以反演重要的有关地表生物的或气候的参数,比如说叶面积指数和地表反照率.一个线性逼近的核驱动BRDF模型通常可以写成下述形式(Roujean等,1992):fiso+kvol(ti,tv,φ)fvol+kgeo(ti,tv,φ)fgeo=r(ti,tv,φ),其中r表示地表的二向反射;kvol和kgeo为通常所说的核函数,即为已知的入射和观测几何特性的函数,分别描述了体散射和几何散射(包括折射和反射);ti是太阳方向天顶角,tv是观测方向天顶角;φ表示太阳-观测方向的相对方位角;fiso,fvol和fgeo为未知的待反演参数,可以用来拟合观测.计算过程的稳定性是由核矩阵的代数算子特征谱和观测噪音/误差来刻画的.因此为了计算地表反照率,成功反演模型参数是至关重要的环节.我们首先考虑了为计算BRDF模型反演的光滑解方法.业已知道,这是一个不适定的反问题.不适定性是由线性核驱动BRDF模型的欠定性表征的,比如说观测严重不足或观测方向范围有限,或者是观测数据高度线性相关以及噪音的污染等.例如,一次单角度观测可以导致一个欠定的系统(核算子的零空间含有非零向量)或者系统无解(系数矩阵的秩不等于增广矩阵的秩).因此,光滑性或正则化技巧应当加以利用来压制不适定性.Li等(2001)应用先验知识把原始模型转换为一个超定的模型并求得最小二乘解.Pokrovsky等(2002)应用QR分解反演BRDF模型.Wang等(2007)考虑到了反演的正则化策略并提出了不适定地表参数反演的一个完整的正则化理论.在文中,强调从不同的空间添加先验信息于反演模型中.首先从数学物理的观点,第一次提出了一个用于反演的施加先验约束的一般的正则化模型,接着阐述了两种正则化策略.第一个是正则化的奇异值分解方法(Wang等,2007),接着提出了一个基于l1空间的反演方法.我们证明了新提出的方法对于有效观测数据不足情况下反演地表参数是可行的,并通过数值试验验证了新提出方法的反演有效性.王彦飞 Shiqian Ma 杨华 王锦地 李小文 2009中国科学(D辑)2009,39,3:3
12Application of Al techniques in monitoring and operation of power systems显示文摘In recent years,the artificial intelligence(Al)technology is becoming more and more popular in many areas due to its amazing performance.However,the application of Al techniques in power systems is still in its infancy.Therefore,in this paper,the application potentials of Al technologies in power systems will be discussed by mainly focusing on the power system operation and monitoring.For the power system operation,the problems,the demands,and the possible applications of Al techniques in control,optimization,and decision making problems are discussed.Subsequently,the fault detection and stability analysis problems in power system monitoring are studied.At the end of the paper,a case study to use the neural network(NN)for power flow analysis is provided as a simple example to demonstrate the viability of Al techniques in solving power system problems.David Wenzhong GAO Qiang WANG Fang ZHANG Xiaojing YANG Zhigang HUANG Shiqian MA Qiao LI Xiaoyan GONG Fei-Yue WANG 2019Frontiers in Energy2019,13,1:2
13A novel CD4+CTL subtype characterized by chemotaxis and inflammation is involved in the pathogenesis of Graves’orbitopathy显示文摘Graves*orbitopathy(GO),the most severe manifestation of Graves'hyperthyroidism(GH),is an autoimmune-mediated inflammatory disorder,and treatments often exhibit a low efficacy.CD4+T cells have been reported to play vital roles in GO progression.To explore the pathogenic CD4-f T cell types that drive GO progression,we applied single-cell RNA sequencing(scRNA-Seq),T cell receptor sequencing(TCR-Seq),flow cytometry,immunofluorescence and mixed lymphocyte reaction(MLR)assays to evaluate CD4+T cells from GO and GH patients.scRNA-Seq revealed the novel GO-spedfic cell type CD4+cytotoxic T lymphocytes(CTLs),which are characterized by chemotactic and inflammatory features.The clonal expansion of this CD4+CTL population,as demonstrated by TCR-Seq,along with their strong cytotoxic response to autoantigens,localization in orbital sites,and potential relationship with disease relapse provide strong evidence for the pathogenic roles of GZMB and IFN-y-secreting CD4+CTLs in GO.Therefore,cytotoxic pathways may become potential therapeutic targets for GO.Yue Wang Ziyi Chen Tingjie Wang Hui Guo Yufeng Liu Ningxin Dang Shiqian Hu Liping Wu Chengsheng Zhang Kai Ye Bingyin Shi 2021Cellular & Molecular Immunology2021,18,3:2
14Low-temperature plasma technology for electrocatalysis显示文摘Electrochemical reactions were widely used in energy storage and conversion devices. The development of low-cost, highly efficient and stable electrocatalyst is essential to a large-scale application of energy storage and conversion devices. Recently, emerging plasma technology has been employed as one of the practical ways to synthesize and modify electrocatalysts due to its unique property. In this review, we summarized the latest applications of plasma in energy storage and conversion, including using it as the preparation and modification technology of the various electrocatalysts and the usage of it as the synthesis technology directly. Firstly, we presented the definition and types of plasma reactors and their respective characteristics. Then, these applications of plasma technology in many essential electrode reactions including carbon dioxide reduction reaction(CO_2RR), nitrogen fixation, oxygen reduction reaction(ORR), oxygen evolution reaction(OER) and hydrogen evolution reaction(HER) were introduced.Finally, the challenges and outlook of plasma technology in energy storage and conversion were summarized, and the solutions and prospected its development in the future were present. Through reviewing the related aspects, readers can have a deeper understanding of the application prospects of plasma in electrocatalysis.Dongdong Wang Yuqin Zou Li Tao Yiqiong Zhang Zhijuan Liu Shiqian Du Shuangquan Zang Shuangyin Wang 2019Chinese Chemical Letters2019,30,4:2
15Wavelength-sensitive photocatalytic H2 evolution from H2S splitting over g-C3N4 with S,N-codoped carbon dots as the photosensitizer显示文摘Photocatalytic splitting of hydrogen sulfide(H2S) for hydrogen evolution is a promising method to solve the energy and environmental issues.In this work,S,N-codoped carbon dots(S,N-CDs)/graphitic carbon nitride(g-C3N4) nanosheet is synthesized by hydrothermal method as an efficient photocatalyst for the decomposition of H2S.In addition to the characterization of the morphology and structure,chemical state,optical and electrochemical performances of S,N-CDs/g-C3N4,hydrogen evolution tests show that the activity of g-C3N4 is improved by introducing S,N-CDs,and the enhancement depends strongly on the wavelength of incident light.The photocatalytic hydrogen production rate of S,N-CDs/g-C3N4 composite reaches 832 μmol g-1h-1, which is 38 times to that of g-C3N4 under irradiation at 460 nm.Density functional theory calculations and electron paramagnetic resonance as well as photoluminescence technologies have altogether authenticated that the unique wavelength-dependent photosensitization of S,N-CDs on g-C3N4;meanwhile,a good match between the energy level of S,N-CDs and g-C3N4 is pivotal for the effective photocatalytic activity.Our work has unveiled the detailed mechanism of the photocatalytic activity enhancement in S,N-CDs/g-C3N4 composite and showed its potential in photocatalytic splitting of H2S for hydrogen evolution.Zhanghui Xie Shan Yu Xiang-Bing Fan Shiqian Wei Limei Yu Yunqian Zhong Xue-Wang Gao Fan Wu Ying Zhou 2021Journal of Energy Chemistry2021,30,1:2
16Fixed point andBregman iterative methods for matrix rank minimization 显示文摘Ma Shiqian Goldfarb D Chen Lifeng 2011Mathematical Programming2011,128,12:1
17The role of VEGF-C/ D and VEGFR-3 in the lymphatic metastasis of early,stage invasive cervical carcinoma 显示文摘Hao Yu Shiqian Zhang Renhua Zhang 2009J Exp Clin Cancer Res2009,28,9:1
18Ecotoxicology of carbon-based engineered nanoparticles: effects of fullerene (C60) on aquatic organisms显示文摘OBERDORSTER E ZHU Shiqian BLICKLEY T M 2006Carbon2006,44,6:1
19Clinical implications of increased lymph vessel density in the lymphatic metastasis of early-stage invasive cervical carcinoma: a clinical immuneohistochemical method study 显示文摘Shiqian Zhang Hao Yu Linlin Zhang 2009BMC Cancer2009,21,9:1
20A fast approach for automatic generation of fuzzy rules by generalized dynamic fuzzy neural networks 显示文摘Shiqian W Meng J E Yang G 2001IEEE Transactions on Fuzzy Systems2001,9,4:1
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