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Physical Experiments to Investigate the Effects of Street Bottom Heating and Inflow Turbulence on Urban Street-Canyon Flow

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Advances in Atmospheric Sciences 2005年第2期22卷 230-237页

作者： Jae-jin KIM Jong-jin BAIK Climate Environment System Research Center Seoul National University Seoul 151-742 KoreaSchool of Earth and Environmental Sciences Seoul National University Seoul 151-742 Korea

The effects of street bottom heating and inflow turbulence on urbanstreet-canyon flow are experimentally investigated using a circulating water channel. Threeexperiments are carried out for a street canyon with a street aspect ratio of 1. Results from eachexperiment with bottom heating or inflow turbulence are compared with those without bottom heatingand appreciable inflow turbulence. It is demonstrated that street bottom heating or inflowturbulence increases the intensity of the canyon vortex. A possible explanation on how street bottomheating or inflow turbulence intensifies the canyon vortex is given from a fluid dynamicalviewpoint.

关键词： urban street-canyon flow street bottom heating inflow turbulence circulating water channel

Nonlinear Inverse Relations of the Bell Polynomials via the Lagrange Inversion Formula (Ⅱ)

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Journal of Systems Science & Complexity 2023年第1期36卷 96-116页

作者： MA Xinrong WANG jin Department of Mathematics Soochow UniversitySuzhou 215006China Department of Mathematics Zhejiang Normal UniversityJinhua 321004China

In this paper,by means of the classical Lagrange inversion formula,the authors establish a general nonlinear inverse relation as the solution to the problem proposed in the paper[***,Nonlinear inverse relations for the Bell polynomials via the Lagrange inversion formula,*** Seq.,Vol.22(2019),Article 19.3.8].As applications of this inverse relation,the authors not only find a short proof of another nonlinear inverse relation due to Birmajer,et al.(2012),but also set up a few convolution identities concerning the Mina polynomials.

关键词： Bell polynomial convolution identity formal power series Lagrange inversion formula Mina polynomial nonlinear inverse relation recurrence relation

Semi-analytical Solutions for Wellbores with Graded Skin Zones in Poroelastic Media

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Acta Mechanica Solida Sinica 2024年第3期37卷 385-395页

作者： Zhiqiang Fan Zhihe jin School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China Department of Mechanical Engineering University of MaineOronoME04469USA

In analyzing the complex interaction between the wellbore and the reservoir formation,the hydromechanical properties of the region proximal to the wellbore,referred to as the“wellbore skin zone”,play a pivotal role in determining flow dynamics and the resulting formation *** models of the wellbore skin zone generally assume a constant permeability throughout,resulting in a sharp permeability discontinuity at the skin-reservoir *** paper introduces a model for a wellbore with a continuously graded skin zone of finite thickness within a poroelastic *** solutions are derived using the Laplace transform method,addressing both positive and negative skin *** results are presented to illustrate the effects of graded permeability/skin zone thickness on pore pressures and stresses around a *** results highlight a distinct divergence in stress and pore pressure fields when comparing wellbores with negative skin zones to those with positive skin zones or no skin at all.

关键词： Poroelastic Graded permeability Analytical solution Wellbore Skin zone

New family of Dirac and Weyl semimetals in XAuTe(X=Na, K,Rb) ternary honeycomb compounds

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Science China(Physics,Mechanics & Astronomy) 2016年第10期59卷 66-71页

作者： Hao Sun jin Zhao International Center for Quantum Design of Functional Materials/Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences and Department of Physics University of Science and Technology of China Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China Department of Physics and Astronomy University of Pittsburgh

We propose a new family of 3D Dirac semimetals based on XAuTe(X = K, Na, Rb) ternary honeycomb compounds, determined based on first-principles calculations, which are shown to be topological Dirac semimetals in which the Dirac points are induced by band inversion. Dirac points with four-fold degeneracy that are protected by C3 rotation symmetry and located on the Γ-A high-symmetry path are found. Through spatial-inversion symmetry breaking, a K(Au0.5 Hg0.5)(Te0.5As0.5) superlattice structure composed of KHgAs and KAuTe compounds is proven to be a Weyl semimetal with type-II Weyl points, which connect electronand hole-like bands. In this superlattice structure, the six pairs of Weyl nodes are distributed along the K-Γ high-symmetry path on the kz = 0 plane. Our research expands the family of topological Dirac and type-II Weyl semimetals.

关键词： Dirac semimetal type-II Weyl semimetal band inversion

Effect of Thermal Radiation Heat Transfer on the Temperature Measurement by the Thermocouple in Premixed Laminar Flames

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Journal of Thermal Science 2022年第2期31卷 541-551页

作者： jin Kairu TIAN Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

In the past 30 years,the effect of thermal radiation and convection heat transfer,which are predominant at high temperature and can affect the measurement accuracy of thermocouple,were not fully considered in the field of laminar flame *** this work,the effect of thermal radiation heat transfer was newly calculated by determining the spectral irradiation heat flux from the whole space to thermocouple and the radiation heat loss from thermocouple junction to *** reveals that the thermocouple itself maintains at high temperature,resulting serious thermal radiation heat loss,which can be compensated via receiving energy from convection-transferred heat as well as thermal radiation emitted by flame and burner *** method was applied to correct the temperatures measured by thermocouple in rich nitromethane flame as *** results indicate that the radiation heat loss plays a dominant role,while the radiations emitted by flame and burner surface account for minor contribution with the percentage of 20.78%at the height above burner(HAB)of 0.4 mm,3.63%at HAB of 2.0 mm and even smaller at higher *** correction states that the maximum temperature error is 117.60 K,where the effect of thermal radiation emitted by flame and burner surface is less than 1.75 ***,it is provably reasonable and feasible to concentrate on the radiation heat loss and ignore the effect of thermal radiation emitted by flame and burner in real combustion processes.

关键词： thermal radiation heat transfer temperature error premixed laminar flame

A new era of flood control strategies from the perspective of managing the 2020 Yangtze River flood

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Science China Earth Sciences 2021年第1期64卷 1-9页

作者： Jun XIA jin CHEN State Key Laboratory of Water Resources and Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China Wuhan University Yangtze River Academy of SciencesChangjiang Water Resources Commission of the Ministry of Water ResourcesWuhan 430015China

Flood control of the Yangtze River is an important part of China’s national water *** July 2020,due to continuous heavy rainfall,the water levels along the middle-lower reaches of the Yangtze River and major lakes constantly exceeded the warning levels,in which Taihu Lake exceeded its highest safety water level and some stations of Poyang Lake reached their highest water levels in its *** August 2020,another huge flood occurred in the Minjiang River and the Jialing River in the upper Yangtze River,and some areas of Chongqing Municipality and other cities along the rivers were inundated,resulting in great pressure on flood control and high disaster *** 2020 Yangtze River flood has received extensive media coverage and raised concerns on the roles of the Three Gorges Dam and other large reservoirs in flood *** we analyze the changes in the pattern of the Yangtze River flood control by comparing the strategies to tackle the three heavy floods occurring in 1954,1998,and *** propose that the overall strategy of the Yangtze River flood control in the new era should adhere to the principle of"Integration of storage and drainage over the entire Yangtze River Basin,with draining floods downstream as the first priority"by using both engineering and non-engineering *** the basis of embankments,the engineering measures should use the Three Gorges Dam and other large reservoirs as the major regulatory means,promote the construction of key flood detention areas,keep the floodways clear,and maintain the ecosystem services of wetlands and *** terms of non-engineering measures,we should strengthen adaptive flood risk management under climate change,standardize the use of lands in flood detention areas,give space to floods,and promote the implementation of flood risk maps and flood insurance *** ultimate goal of this new flood control system is to enhance the adaptability to frequent floods and increase the resilience to extre

关键词： The 2020 Yangtze River flood Yangtze River Flood Control System Three Gorges Dam Protection of wetlands and shoals Non-engineering measures

Hepatic perfusion disorders: Etiopathogenesis and related diseases

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World Journal of Gastroenterology 2006年第20期12卷 3265-3270页

作者： jin-Lin Tian jin-Shan Zhang Department of Radiology Chinese PLA General Hospital Beijing 100853 China

In this article, we have reviewed the hepatic perfusion disorder （HPD）, etiopathogenesis of HPD and corresponding diseases. Review of the literature was based on computer searches （PubMed, Index Medicus） and personal experiences. We considered HPD reflects perfusion differences due to redistribution of arterial blood flow among segments, subsegments and lobes of the liver. The plain CT scan findings of HPD manifests as triangular or wedge-shaped areas of low attenuation. On contrast-enhanced CT scan, HPD manifests multiple （or single） transient wedge-shaped, rotundloid or irregular appearance, homogeneous hyperattenuation （in less cases, hypoattenuation） during the hepatic arterial phase （HAP） and isoattenuated or slightly hyperattenuated areas during the portal arterial phase. Dynamic enhanced magnetic resonance （MR） features are similar to enhanced CT scan. Angiographic findings include non-opacification of portal vein on portograms or wedge-shaped segmental staining in arterial and parenchymal phases on hepatic angiograms. The causes of HPD are arterioportal shunts （APS）, intrahepatic vascular compressions and portal vein occlusion, steal phenomenon by hypervascular tumors, vascular variations and any other unknown reasons. It is very important for radiologists to be familiar with the various appearances of HPD to avoid false-positive diagnosis of pseudolesions and not to overestimate the extent of the disease.

关键词： Etiopathogenesis Hepatic perfusion disorders Diseases

Advanced Algorithm for Parameters Estimation of Negative Binomial Distribution with High Dimensional Sparse Group Structure

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Journal of Systems Science & Complexity 2024年第5期37卷 2173-2195页

作者： LI Meiqi jin Baisuo School of Management University of Science and Technology of ChinaHefei 230000China

Negative binomial regression is a powerful technique for modeling count data,particularly when dealing with ***,estimating the parameters for large-dimensional sparse models is challenging due to the complexity of optimizing the mean and dispersion parameter of the negative binomial *** address this issue,the authors propose a novel approach that employs two iterations of the majorize-minimize(MM)algorithm,one for estimating the dispersion parameter and the other for estimating the mean *** approaches improve the convergence speed and stability of the *** authors also use group penalty for variable selection,which enhances the accuracy and efficiency of the *** proposed method provides an explicit solution,simplifies the iteration process,and maintains good stability while ensuring algorithm ***,the authors apply the proposed algorithm to the zero-inflated model and demonstrate its promising predictive performance on specific data *** research has important implications for count data modeling and analysis in various fields,such as data mining,machine learning,and bioinformatics.

关键词： Group structure majorize-minimize(MM) negative binomial

From 'glass basins' to 'glass barriers'

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National Science Review 2024年第6期11卷 95-96页

作者： Yuliang jin Institute of Theoretical Physics Chinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences Center for Theoretical Interdisciplinary Sciences Wenzhou InstituteUniversity of Chinese Academy of Sciences

If a supercooled liquid is cooled rapidly to avoid crystallization, a glass is *** this procedure, the viscosity can increase by more than 10 orders of magnitude over a small temperature range near the glass transitio... 详细信息

关键词： glass basins from barriers