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基于格网尺度的中小型城市洪涝灾害风险评估

华北水利水电大学学报(自然科学版) 2025年第1期46卷 78-86页

作者：李洁雷震辛文鹏商丘师范学院测绘与规划学院河南商丘476000 河南省黄河故道生态保护与治理工程技术研究中心商丘师范学院河南商丘476000 威海市气象局山东威海264200

为定量评估黄河下游中小型城市商丘市的洪涝灾害风险性,利用GIS技术,以栅格格网(500 m×500 m)为研究尺度,从承载体暴露性、防灾减灾能力、致灾因子危险性和孕灾环境敏感性4个角度选取14个评估因子,采用层次分析法和地理加权叠加法构建... 详细信息

为定量评估黄河下游中小型城市商丘市的洪涝灾害风险性,利用GIS技术,以栅格格网(500 m×500 m)为研究尺度,从承载体暴露性、防灾减灾能力、致灾因子危险性和孕灾环境敏感性4个角度选取14个评估因子,采用层次分析法和地理加权叠加法构建风险评估模型,综合评价其洪涝灾害风险情况。结果表明:造成洪涝灾害较严重的影响因子有夏季降水变率、河流密度、年均降水量、植被覆盖度和坡度,其中夏季降水变率的影响率高达15.77%;商丘市风险区自南向北呈现层次性分布特征,高风险区的面积占比高达14.5%,且高风险区沿河流走向分布;黄河故道的高风险区主要集中在梁园区,在民权县中部和虞城县西部零星分布着一些较高风险区。建议政府相关部门避免城镇过度开发,改善生态环境,做好防涝排涝,利用高新技术进行防灾预测,并推进水利工程建设。

关键词：洪涝灾害风险评估 GIS 栅格格网中小型城市商丘市

中国国际工程企业应对技术标准压力的策略研究

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南开管理评论 2025年第1期28卷 103-112页

作者：沈文欣刘扬雷振唐文哲北京交通大学大学经济管理学院中华人民共和国水利部中国三峡(欧洲)有限公司绿地开发部清华大学水利系

由中外技术标准差异引发的制度压力是中国国际工程企业跨国经营时普遍面临的重要挑战。本文选取中国电建在6个典型国家市场中应对技术标准压力的成功实践进行案例研究。基于制度理论,构建了“技术标准压力+制度距离”理论框架,分析了技... 详细信息

由中外技术标准差异引发的制度压力是中国国际工程企业跨国经营时普遍面临的重要挑战。本文选取中国电建在6个典型国家市场中应对技术标准压力的成功实践进行案例研究。基于制度理论,构建了“技术标准压力+制度距离”理论框架,分析了技术标准压力策略选择的组合性特征和内在规律。研究发现,企业在策略选择时会经历“碰撞—动态博弈—策略定型”的过程。在较大技术标准压力下,无论制度距离较大还是较小,企业会优先采取“适应为主,折中为辅”的效率型策略;在面临较小技术标准压力和较大制度距离时,企业会优先采取“折中为主,引导为辅”的平衡型策略;在面临较小技术标准压力和较小制度距离时,企业会优先采取“引导为主,折中为辅”的利润型策略。

关键词：技术标准国际工程企业国际化制度距离

Revisit of the Faddeev Model in Dimension Two

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Chinese Annals of Mathematics,Series B 2022年第5期43卷 797-818页

作者： Shijie DONG zhen lei SUSTech International Center for Mathematics Department of MathematicsSouthern University of Science and TechnologyShenzhen 518055China School of Mathematical Sciences Shanghai Center for Mathematical SciencesFudan UniversityShanghai 200433China

The Faddeev model is a fundamental model in relativistic quantum field theory used to model elementary particles. The Faddeev model can be regarded as a system of non-linear wave equations with both quasi-linear and semi-linear non-linearities, which is particularly challenging in two space dimensions. A key feature of the system is that there exist undifferentiated wave components in the non-linearities, which somehow causes extra difficulties. Nevertheless, the Cauchy problem in two space dimenions was tackled by lei-Lin-Zhou(2011) with small, regular, and compactly supported initial data, using Klainerman’s vector field method enhanced by a novel angular-radial anisotropic *** the present paper, the authors revisit the Faddeev model and remove the compactness assumptions on the initial data by lei-Lin-Zhou(2011). The proof relies on an improved L2norm estimate of the wave components in Theorem 3.1 and a decomposition technique for non-linearities of divergence form.

关键词： Faddeev model in R^(1+2) Global existence Null condition

On scaling invariance and type-Ⅰ singularities for the compressible Navier-Stokes equations

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Science China Mathematics 2019年第11期62卷 2271-2286页

作者： zhen lei Zhouping Xin School of Mathematical Sciences LMNS and Shanghai Key Laboratory for Contemporary Applied MathematicsFudan UniversityShanghai 200433China The Institute of Mathematical Sciences and Department of Mathematics The Chinese University of Hong KongHong KongChina

We find a new scaling invariance of the barotropic compressible Navier-Stokes equations. Then it is shown that type-Ⅰ singularities of solutions with■ can never happen at time T for all adiabatic number γ 1. Here κ > 0 does not depend on the initial *** is achieved by proving the regularity of solutions under■ This new scaling invariance also motivates us to construct an explicit type-Ⅱ blowup solution for γ > 1.

关键词： type-Ⅰ singularity compressible Navier-Stokes equations scaling invariance blowup rate

On Li-Yau Heat Kernel Estimate

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Acta Mathematica Sinica,English Series 2021年第8期37卷 1205-1218页

作者： Lu LI zhen lei ZHANG School of Mathematics Capital Normal UniversityBeijing 100048P.R.China

We present some improvements of the Li-Yau heat kernel estimate on a Riemannian manifold with Ricci curvature bounded *** a consequence we prove a gradient estimate to the heat kernel with an optimal leading term.

关键词： Heat kernel Li-Yau estimate gradient estimate

Strong Consistency and CLT for the Random Decrement Estimator

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Acta Mathematica Sinica,English Series 2010年第9期26卷 1613-1626页

作者： Pierre BERNARD Liang zhen lei Laboratoire de Mathematiques Universite Blaise Pascal CNRS 63177 Aubiere France Institute of Mathematical Sciences Capital Normal University Beijing 100048 P. R. China

The random decrement technique （RDT）, introduced in the sixties by Cole [NASA CR- 2005, 1973], is a very performing method of analysis for vibration signature of a structure under ambient loading. But the real nature of the random decrement signature has been misunderstood until now. Moreover, the various interpretations were made in continuous time setting, while real experimental data are obtained in discrete time. In this paper, the really implemental discrete time algorithms are studied. The asymptotic analysis as the number of triggering points go to infinity is achieved, and a Law of Large Numbers as well as a Central Limit Theorem is proved. Moreover, the limit as the discretization time step goes to zero is computed, giving more tractable formulas to approximate the random decrement. This is a new approach of the famous ＂Kac-Slepian paradox＂ [Ann. Math. Star., 30, 1215-1228 （1959）]. The main point might be that the RDT is a very efficient functional estimator of the correlation function of a stationary ergodic Gaussian process. Very fast, it is to classical estimators what Fast Fourier Transform （FFT） is to ordinary Discrete Fourier Transforms.

关键词： Random decrement estimator law of large numbers center limit theorem

On the Synchronizable System

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Chinese Annals of Mathematics,Series B 2020年第6期41卷 821-828页

作者： zhen lei Tatsien LI Bopeng RAO School of Mathematical Sciences Fudan UniversityShanghai 200433China Shanghai Key Laboratory for Contemporary Applied Mathematics Nonlinear Mathematical Modeling and Methods Laboratory Institut de Recherche Mathematique Avancee Universite de Strasbourg67084 StrasbourgFrance

In this paper,the synchronizable system is defined and studied for a coupled system of wave equations with the same wave speed or with different wave speeds.

关键词： Synchronizable system Synchronization solution Coupled system of wave equations Exact boundary synchronization

Synthesis of cyclicβ-silylenones via oxidative rearrangement of tertiaryα-hydroxy allylsilanes with PCC

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Chinese Chemical Letters 2011年第3期22卷 306-309页

作者： Xia Wu Jian lei zhen lei Song Key Laboratory of Drug-Targeting of Education Ministry and Department of Medicinal Chemistry West China School of Pharmacy Sichuan University Chengdu 610041 China

An oxidative rearrangement of cyclic tertiary a-hydroxy allylsilanes has been carried out in refluxing ClCH_2CH_2Cl with pyridinium chlorochromate（PCC）.The reaction provides a convenient method to synthesize cyclic... 详细信息

关键词： Pyridinium chlorochromate Oxidative rearrangement Cyclicβ-silylenones

Reaction mechanisms between molten CaF2-based slags and molten 9CrMoCoB steel

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International Journal of Minerals,Metallurgy and Materials 2020年第5期27卷 611-619页

作者： lei-zhen Peng Zhou-hua Jiang Xin Geng School of Metallurgy Northeastern UniversityShenyang 110819China

Investigating the reaction mechanism between slag and 9CrMoCoB steel is important to develop the proper slag and produce qualified ingots in the electroslag remelting(ESR) process. Equilibrium reaction experiments between molten 9CrMoCoB steel and the slags of 55 wt%CaF2–20 wt%CaO–3 wt%MgO–22 wt%Al2O3–xwt%B2O3(x = 0.0, 0.5, 1.0, 1.5, 2.0, 3.0) were conducted. The reaction mechanisms between molten 9 CrMoCoB steel and the slags with different B2O3 contents were deduced based on the composition of the steel and slag samples at different reaction times. Results show that B content in the steel can be controlled within the target range when the B2O3 content is 0.5 wt% and the FeO content ranges from 0.18 wt% to 0.22 wt% in the slag. When the B2O3 content is ≥1 wt%, the reaction between Si and B2O3 leads to the increase of the B content of steel. The additions of SiO2 and B2O3 to the slag should accord to the mass ratio of [B]/[Si] in the electrode, and SiO2 addition inhibits the reaction between Si and Al2O3.

关键词： 9CrMoCoB electroslag remelting B2O3 thermodynamic calculation reaction mechanism