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Experimental investigation on debris flow resistance and entrainment characteristics:effects of the erodible bed with discontinuous grading

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Journal of Mountain Science 2022年第8期19卷 2397-2419页

作者： LI Pu WANG Jia-ding hu Kai-heng QIU hai-jun XIE Jia-lin State Key Laboratory of Continental Dynamics/Department of Geology Northwest UniversityXi'an 710069China Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of Sciences&Ministry of Water ConservancyChengdu 610041China College of Urban and Environmental Sciences Northwest UniversityXi'an 710127China

Debris flow deposits in natural channels typically have a wide grain size distribution(GSD).The effects of bed sediment GSD on the basal entrainment rate are neglected in current debris flow erosion *** investigations have detected three different vertical graded bedding structures:normal,inverse,and mixed-gradation,characterized by discontinuous gradation sediment and almost without intermediate-sized *** study conducted small-scale flume experiments to investigate the debris flow resistance forces and entrainment characteristics by incorporating the effects of discontinuous grading bed *** graded bed sediments with varying fine particle content,volumetric water content(VWC),and roundness were designed for *** flow resistance in erodible beds generally increased in the group with gravel of larger-sized coarse particle,lower roundness,and higher bed sediment *** discontinuous grading bed sediment,the entrained depths increased in the group with gravel of smaller coarse particle sizes,larger amounts of fine particles,and higher sediment roundness,and decreased with larger *** abnormality may be attributed to the disproportionately large effects of viscous flow resistance in our small-scale flume *** maximum erosion rates of the continuous bed sediment were higher than those of the corresponding discontinuous bed sediment with the same maximum coarse gravel *** is because,for discontinuous grading bed sediments,localized failure of intermediate-sized sediment grains may cause a large-scale collapse of the solid grain skeleton and enhance basal entrainment rates.A revised formula for calculating the debris flow entrainment rate is proposed by incorporating the kurtosis coefficient,which describes the distribution of discontinuous bed sediments and fine particle *** revised formula could facilitate an elaborate estimation of basin erosion and sediment runoff and reveal the development an

关键词： Debris flow Resistance force Entrainment characteristic Discontinuous gradation Roundness Entrainment model

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Size effects on the mixed modes and defect modes for a nano-scale phononic crystal slab

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Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 21-34页

作者： jun JIN Ningdong hu Hongping hu Department of Mechanics School of Aerospace EngineeringHuazhong University of Science and TechnologyWuhan 430074China hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment Huazhong University of Science and TechnologyWuhan 430074China

The size-dependent band structure of an Si phononic crystal(PnC)slab with an air hole is studied by utilizing the non-classic wave equations of the nonlocal strain gradient theory(NSGT).The three-dimensional(3D)non-classic wave equations for the anisotropic material are derived according to the differential form of the *** on the the general form of partial differential equation modules in COMSOL,a method is proposed to solve the non-classic wave *** bands of the in-plane modes and mixed modes are *** in-plane size effect and thickness effect on the band structure of the PnC slab are *** is found that the thickness effect only acts on the mixed *** relative width of the band gap is widened by the thickness *** effects of the geometric parameters on the thickness effect of the mixed modes are further studied,and a defect is introduced to the PnC supercell to reveal the influence of the size effects with stiffness-softening and stiffness-hardening on the defect *** study paves the way for studying and designing PnC slabs at nano-scale.

关键词： band structure phononic crystal(PnC) nonlocal strain gradient theory(NSGT) size effect

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FINITE ELEMENT APPROXIMATIONS OF SYMMETRIC TENSORS ON SIMPLICIAL GRIDS IN R^n： THE HIGHER ORDER CASE

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Journal of Computational Mathematics 2015年第3期33卷 283-296页

作者： jun hu LMAM School of Mathematical Sciences and Beijing International Center for Mathematical Research Peking University Beijing 100871 P. R. China.

The design of mixed finite element methods in linear elasticity with symmetric stress approximations has been a longstanding open problem until Arnold and Winther designed the first family of mixed finite elements where the discrete stress space is the space of H（div,Ω;S）-Pk＋1 tensors whose divergence is a Pk-1 polynomial on each triangle for k ≥ 2. Such a two dimensional family was extended, by Arnold, Awanou and Winther, to a three dimensional family of mixed elements where the discrete stress space is the space of H（div, Ω; S）-Pk＋2 tensors, whose divergence is a Pk-1 polynomial on each tetrahedron for k ≥ 2. In this paper, we are able to construct, in a unified fashion, mixed finite element methods with symmetric stress approximations on an arbitrary simplex in R^n for any space dimension. On the contrary, the discrete stress space here is the space of H（div,Ω; S）-Pk tensors, and the discrete displacement space here is the space of L^2（Ω; R^n）-Pk＋1 vectors for k ≥ n＋ 1. These finite element spaces are defined with respect to an arbitrary simplicial triangulation of the domain, and can be regarded as extensions to any dimension of those in two and three dimensions by hu and Zhang.

关键词： Mixed finite element Symmetric finite element First order system Simplicial grid Inf-sup condition.

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Tillage force and disturbance characteristics of different geometric-shaped subsoilers via DEM

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Advances in Manufacturing 2020年第3期8卷 392-404页

作者： Jin Tong Xiao-hu Jiang Yue-Ming Wang Yun-hai Ma jun-Wei Li Ji-Yu Sun Key Laboratory of Bionic Engineering Ministry of EducationJilin UniversityChangchun130022People’s Republic of China College of Biology and Agricultural Engineering Jilin UniversityChangchun130022People’s Republic of China College of Mechanical and Electrical Engineering Shihezi UniversityShihezi832000XinjiangPeople’s Republic of China

With the increased use of agricultural machinery in field operations,soil compaction has become increasingly severe,and the plough pan has become *** is an excellent way to address this ***,it is limited by high energy consumption,which is closely related to tillage *** investigate the effect of the geometric shape of shanks and tines on tillage force and soil disturbance in loam,a layered soil model in accordance with the actual conditions was established and five different subsoilers were simulated via discrete element *** results indicated that the shank impacted soil disturbance and tine impacted tillage *** draft force of curved shank and chisel tine was 8%less than that of the straight shank and sweep *** straight shank and sweep tine produced a larger furrow profile and a higher furrow *** subsoiler with curved shank and chisel tine(C-C)exhibited the lowest specific resistance(12.87,17.52,19.46 and 21.18 kN/m^2 in the 30,35,40 and 45 cm tillage depth,respectively)considering the draft force and soil disturbance ***,these results will facilitate in the selection of a suitable subsoiler and design of new subsoilers with lower energy consumption requirements for loam areas worldwide.

关键词： Subsoiler Discrete element method(DEM) Tillage force Soil disturbance Soil compaction

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Theoretical Calculations on the Second-order Nonlinear Optical Property of Chiral Bis-corroles

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Chinese Journal of Structural Chemistry 2007年第8期26卷 955-961页

作者： YING Xiao DENG Qin LIAO Shi-jun hu Xi-Ming LIU hai-Yang CHANG Chi-Kwong Department of Applied Physics South China University of Technology Guangzhou 510641 China Department of Applied Chemistry South China University of Technology Guangzhou 510641 China Department of Chemistry The Hongkong University of Science and Technology Hongkong China

The second-order nonlinear optical （NLO） properties of 5,10,15-triphenylcorrole （TPC）, 5,10,15,20-tetraphenylporphyrin （TPP） and L-amino acid bridged bis-corroles 1,2,3 and 4 have been calculated by using TDHF/PM3 method based on the RHF/6-31G （TPC and TPP） or semiempirical PM3 （1, 2, 3, 4） optimized geometries. Calculation results showed TPC and TPP have C1 and D2h symmetry, respectively when N-H protons are localized on the nitrogen atoms. TPC is the second-order NLO active chromophore due to the cancellation of centrosymmetrical structure and its first hyperpolarizability β increases to 11.524×10^-30 esu. Under electrical dipole approximation, βvalues of bis-corroles 1, 2, 3 and 4 vary from 9.831×10^-30 to 14.221×10^-30 esu, and no much improvement in the first hyperpolarizability was observed as compared to TPC ***, β values of bis-corroles 1, 2, 3 and 4 are improved by about 4 times as compared to their bis-porphyrin counterparts. The analysis of β components indicates that β of this kind of bis-corroles is mainly contributed from its radial component βr. With the variation of amino acid side chains, βHRS, β,βxyz, βr and βa of bis-corroles change remarkably. Chiral L-amino acid bridged bis-corroles 2, 3 and 4 have a right-handed helix structure, and their chiral component βxyz matches βxyz ∝ r^2 ζ/L^4 （helix parameters）, showing the second-order chiral NLO response of these bis-corroles could be described by one-electron helical model theory. It was found that the radial component βr of chiral helix bis-corroles also matches βr ∝ r^2 ζ/L^4.

关键词： corrole amino acid chiral bis-corrole the second-order NLO TDHF/PM3

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Beneficial effects of silicon on photosynthesis of tomato seedlings under water stress

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Journal of Integrative Agriculture 2018年第10期17卷 2151-2159页

作者： ZHANG Yi SHI Yu GONG hai-jun ZHAO hai-liang LI huan-li hu Yan-hong WANG Yi-chao College of Horticulture Shanxi Agricultural University College of Horticulture Northwest A&F University

Silicon can improve drought tolerance of plants,but the mechanism still remains *** studies have mainly concentrated on silicon-accumulating plants,whereas less work has been conducted in silicon-excluding plants,such as tomato（Solanum lycopersicum L.）.In this study,we investigated the effects of exogenous silicon（2.5 mmol L^（-1））on the chlorophyll fluorescence and expression of photosynthesis-related genes in tomato seedlings（Zhongza 9）under water stress induced by 10%（w/v）polyethylene glycol（PEG-6000）.The results showed that under water stress,the growth of shoot and root was inhibited,and the chlorophyll and carotenoid concentrations were decreased,while silicon addition improved the plant growth and increased the concentrations of chlorophyll and *** water sterss,chlorophyll fluorescence parameters such as PSII maximum photochemical efficiency（F_v/F_m）,effective quantum efficiency,actual photochemical quantum efficiency（Ф_（PSII））,photosynthetic electron transport rate（ETR）,and photochemical quenching coefficient（q_P）were decreased;while these changes were reversed in the presence of added *** expressions of some photosynthesis-related genes including PetE,PetF,PsbP,PsbQ,PsbW,and Psb28 were down-regulated under water stress,and exogenous Si could partially up-regulate their *** results suggest that silicon plays a role in the alleviation of water stress by modulating some photosynthesis-related genes and regulating the photochemical process,and thus promoting photosynthesis.

关键词： tomato water stress silicon photosynthesis

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“暂缓不起诉”制度的合法性缺失及其整合

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西南交通大学学报（社会科学版） 2004年第5期5卷 131-135页

作者：周海军胡水清上海市工商行政管理局闵行分局上海201100 浙江大学企业管理系浙江杭州310027

　法治的价值之一就在于保障法律规则的确定性和可预期性。一项新制度的设立有必要从法治的角度来审视其合法性与正当性,以维护法制的权威性和统一性。"暂缓不起诉"是地方司法机关创设的一项"新"制度,突破了现行的《刑事诉讼法》等法律... 详细信息

　法治的价值之一就在于保障法律规则的确定性和可预期性。一项新制度的设立有必要从法治的角度来审视其合法性与正当性,以维护法制的权威性和统一性。"暂缓不起诉"是地方司法机关创设的一项"新"制度,突破了现行的《刑事诉讼法》等法律的相关规定,缺失合法性。但作为一项新制度,它反映了一定的诉讼价值,具有一定合理性和正当性。因而,应采取适宜措施,在实践中加强"暂缓不起诉"制度正当性与合法性的整合。

关键词：《刑事诉讼法》 “暂缓不起诉”制度刑罚权司法公正

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Source of silica and its implications for organic matter enrichment in the Upper Ordovician-Lower Silurian black shale in western hubei Province,China:Insights from geochemical and petrological analysis

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Petroleum Science 2022年第1期19卷 74-90页

作者： Quan-Sheng Cai Ming-Yi hu Bao-Min Zhang Ngong Ngia An Liu Rui-Quan Liao Oumar Kane hai Li Zhong-Gui hu Qing-Jie Deng jun-jun Shen School of Geosciences Yangtze UniversityWuhanHubei 430100China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education(China University of Geosciences) WuhanHubei 430074China Wuhan Center of China Geological Survey WuhanHubei 430205China Department of Geology University of BueaP.O.Box 63BueaSouthwestCameroon School of Petroleum Engineering Yangtze UniversityWuhanHubei 430100China

To improve the understanding of the relationship between silica source and organic matter accumulation,the origin of silica and its implications for organic matter enrichment in the Upper OrdovicianLower Silurian(O_(3)w-S_(1)l)black shale in western hubei Province in the middle Yangtze area,were investigated through geochemical and petrological *** results show that the O_(3)w-S_(1)l black shale is mainly composed of five lithofacies with varying graptolite abundance,total organic carbon(TOC),and silica *** silica and terrigenous siliciclastic input constitute the main silica sources in O_(3)w-S_(1)l black shale and they exhibit an upward inverse variation trend interpreted to be related to sea-level ***,with the increase in biogenic silica content or decrease in terrigenous siliciclastic input,TOC values in black shale initially rise and then fall,which is different from originally expected simple linear *** infer that organic matter enrichment and the distribution of silica from different origins are controlled by sea-level changes and variations in terrigenous input in a continental shelf with little hydrothermal *** environment with appropriate sea level and terrigenous input should be most favorable for organic matter accumulation,rather than one with excessive high sea level and less terrigenous input.

关键词： Biogenic silica Terrigenous siliciclastic input Organic matter enrichment Black shale Continental shelf Sea-level change Wufeng-Longmaxi formations

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UNIFORMLY A POSTERIORI ERROR ESTIMATE FOR THE FINITE ELEMENT METHOD TO A MODEL PARAMETER DEPENDENT PROBLEM

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Journal of Computational Mathematics 2008年第5期26卷 716-727页

作者： Yiran Zhang jun hu LMAM and School of Mathematical Sciences Peking University Beijing 100871 China

This paper proposes a reliable and efficient a posteriori error estimator for the finite element methods for the beam problem. It is proved that the error can be bounded by the computable error estimator from above an... 详细信息

关键词： The beam problem A posteriori error estimator Finite element method.

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Global sensitivity analysis based on high-dimensional sparse surrogate construction

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 797-814页

作者： jun hu Shudao ZHANG Institute of Applied Physics and Computational Mathematics

Surrogate models are usually used to perform global sensitivity analysis （GSA） by avoiding a large ensemble of deterministic simulations of the Monte Carlo method to provide a reliable estimate of GSA indices. However, most surrogate models such as polynomial chaos （PC） expansions suffer from the curse of dimensionality due to the high-dimensional input space. Thus, sparse surrogate models have been proposed to alleviate the curse of dimensionality. In this paper, three techniques of sparse reconstruc- tion are used to construct sparse PC expansions that are easily applicable to computing variance-based sensitivity indices （Sobol indices）. These are orthogonal matching pursuit （OMP）, spectral projected gradient for L1 minimization （SPGL1）, and Bayesian compressive sensing with Laplace priors. By computing Sobol indices for several benchmark response models including the Sobol function, the Morris function, and the Sod shock tube problem, effective implementations of high-dimensional sparse surrogate construction are exhibited for GSA.

关键词： global sensitivity analysis (GSA) curse of dimensionality sparse surrogate construction polynomial chaos (PC) compressive sensing

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