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Risk assessment of hazardous materials transportation:A review of research progress in the last thirty years

Journal of Traffic and Transportation Engineering(English Edition) 2022年第4期9卷 571-590页

作者： jian Guo cheng Luo College of Civil Engineering Zhejiang University of TechnologyHangzhou 310023China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

In recent years,hazardous materials transportation accidents occur frequently,causing huge casualties and property losses.Risk assessment of hazardous materials transportation has been constantly investigated by researchers and decision-makers.In order to study the research progress of risk assessment of hazardous materials transportation,so as to better reveal relevant problems.This review systematically analyzes the existing literature,from 1991 to 2020,on risk assessment models and methods of hazardous materials transportation,and segregates the relevant studies based on unimodal and intermodal transportation systems.Additionally,an example is considered to analyze the characteristics of each risk assessment model of unimodal transportation,and a novel detailed classification is proposed for the risk assessment problems.The results indicate that the research on the risk assessment model of road transportation of hazardous materials is comprehensive,whereas that based on the railway and intermodal transportations is deficient.In comparison with the traditional risk assessment model,the conditional value-at-risk model presents a flexible decision-making framework for decision-makers and controls risk preference between risk neutrality and risk aversion.Owing to the difficulty in achieving door-to-door railway transportation and the increased risks associated with the intermodal transportation,the conclusion that the risk of railway and multimodal transportation of hazardous materials is lower than that of road transportation is not universal.Transport operators and governments can combine the advantages of different transportation modes,such as low risk,low cost,high flexibility,and high reliability,to achieve public safety and improve the competence of the system.Based on the proposed classification,this review identifies the existing trends and research gaps and summarizes future research directions.

关键词： Transportation Hazardous materials Risk assessment Transportation modes Risk model

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A new era for paclitaxel biosynthesis is coming

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Molecular Plant 2024年第3期17卷 370-371页

作者： Xiaonan Liu Xiaoxi Zhu Jian Cheng Huifeng jiang Key Laboratory of Engineering Biology for Low-carbon Manufacturing Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin 300308China National Center of Technology Innovation for Synthetic Biology Tianjin 300308China

Paclitaxel(Taxol)stands out as a tetracyclic diterpenoid natural product derived from the endangered plant Taxus.Recognized as a pivotal broad-spectrum anticancer drug,it has garnered widespread attention due to its low yield,intricate structure,unique anticancer mechanism,and remarkable efficacy(Tong et al.,2021).Although chemists achieved the total synthesis of paclitaxel 30 years ago,after decades of research,the natural biosynthetic pathway for its production remains an enigma(Ajikumar et al.,2010;Malci et al.,2023).A recent breakthrough,published in Molecular Plant by Alisdair R.Fernie's team,unveils a minimal gene set of 18 genes required for paclitaxel biosynthesis(Zhang et al.,2023),representing a significant mark toward unraveling the entire biosynthetic pathway and enhancing paclitaxel production efficiency.

关键词： breakthrough representing synthesis

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Experimental investigation on pressure-buildup characteristics of a water lump immerged in a molten lead pool

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Nuclear Science and Techniques 2023年第3期34卷 25-39页

作者： Zi-jian Deng Song-Bai cheng Hui cheng Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China

Motivated to understand the pressure-buildup characteristics in a circumstance of a water droplet immerged inside a heavy liquid metal pool,which is a key phenomenon during a Steam Generator Tube Rupture accident of Lead-cooled Fast Reactor,many experiments have been conducted by injecting water lumps into a molten lead pool at Sun Yat-sen University.In order to deepen the understanding of the influence of melt material,this lead experiment was compared with a Lead-Bismuth-Eutectic(LBE)experiment in the literature.For both experiments,a steam explosion occurred in a small part of the experi-mental runs,which generally leads to strengthened pressure buildup.Regarding the non-explosion experimental cases,the impact of all parameters employed in lead experiments(i.e.,water lump volume,water lump shape,molten pool depth,and temperature of water and melt)on the pressure buildup is non-negligible and similar to that in our previous experiments using LBE.Notably,limited pressure buildup with an increase in water lump volume was also observed.A slightly more violent pressure buildup tends to appear in the lead experiments than in the LBE experiments under the same experimental conditions,which may be due to the higher thermal conductivity of lead than of LBE.In a few experimental runs with a relatively low melt temperature close to the melting point of lead,local solidification of liquid lead was observed,restricting pressure buildup.For the lead and LBE experiments,the calculated melt kinetic energy conversion efficiencyηhas a relatively small value(not exceeding 1.6%),and theηvalues have an overall positive correlation with the impulse on the molten pool.

关键词： Lead-cooled fast reactor Steam generator tube rupture accident Pressure-buildup characteristics Experimental study Melt material

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Sharp Condition for Global Existence of Supercritical Nonlinear Schrodinger Equation with a Partial Confinement

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Acta Mathematicae Applicatae Sinica 2023年第1期39卷 202-210页

作者： cheng-lin WANG jian ZHANG University of Electronic Science and Technology of China Chengdu 611731China

We study the L^(2)-supercritical nonlinear Schrodinger equation(NLS) with a partial confinement,which is the limit case of the cigar-shaped model in Bose-Einstein condensate(BEC). By constructing a cross constrained variational problem and establishing the invariant manifolds of the evolution fow, we show a sharp condition for global existence.

关键词： nonlinear Schrodinger equation Bose-Einstein condensate cross-constrained variational problem global existence sharp condition

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Shallow water bathymetry based on a back propagation neural network and ensemble learning using multispectral satellite imagery

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Acta Oceanologica Sinica 2023年第5期42卷 154-165页

作者： Sensen Chu Liang cheng Jian Cheng Xuedong Zhang Jie Zhang Jiabing Chen Jinming Liu jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Collaborative Innovation Center of South China Sea Studies Nanjing UniversityNanjing 210093China School of Geography and Ocean Science Nanjing UniversityNanjing 210023China jiangsu Center for Collaborative Innovation in Novel Software Technology and Industrialization Nanjing 210023China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China Institute of Defense Engineering Academy of Military SciencesBeijing 100036China

The back propagation(BP)neural network method is widely used in bathymetry based on multispectral satellite imagery.However,the classical BP neural network method faces a potential problem because it easily falls into a local minimum,leading to model training failure.This study confirmed that the local minimum problem of the BP neural network method exists in the bathymetry field and cannot be ignored.Furthermore,to solve the local minimum problem of the BP neural network method,a bathymetry method based on a BP neural network and ensemble learning(BPEL)is proposed.First,the remote sensing imagery and training sample were used as input datasets,and the BP method was used as the base learner to produce multiple water depth inversion results.Then,a new ensemble strategy,namely the minimum outlying degree method,was proposed and used to integrate the water depth inversion results.Finally,an ensemble bathymetric map was acquired.Anda Reef,northeastern Jiuzhang Atoll,and Pingtan coastal zone were selected as test cases to validate the proposed method.Compared with the BP neural network method,the root-mean-square error and the average relative error of the BPEL method can reduce by 0.65–2.84 m and 16%–46%in the three test cases at most.The results showed that the proposed BPEL method could solve the local minimum problem of the BP neural network method and obtain highly robust and accurate bathymetric maps.

关键词： bathymetry back propagation neural network ensemble learning local minimum problem multispectral satellite imagery

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Optimization of perovskite/carbon interface performance using N-doped coal-based graphene quantum dots and its mechanism analysis

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Journal of Energy Chemistry 2023年第4期79卷 242-252页

作者： Qixu Hu Xiaoyu Yang Ying Qi Peng Wei Jian Cheng Yahong Xie State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources School of Chemical Engineering and TechnologyXinjiang UniversityUrumqi 830017XinjiangChina Department of Materials&Chemical Engineering Hanyang UniversitySeoul 04763South Korea

Optimizing the interfacial properties between perovskite and carbon electrodes has always been an important way to improve the photoelectric conversion efficiency(PCE)of carbon-based perovskite solar cells(C-PSCs)and facilitate their commercialization.In this paper,nitrogen-doped graphene quantum dots(N-GQDs)with fluorescent properties were successfully prepared using inexpensive coal as raw material by a facile and environmentally friendly chemical reagent oxidation.The results show that the electron-rich pyridinic nitrogen in N-GQDs can act as Lewis bases to form coordination bonds with uncoordinated lead ions by sharing electron pairs,thereby reducing the defect density and nonradiative recombination of photo-generated electron-hole,and extending lifetime of charge carriers.In addition,due to the passivation of N-GQDs,the hysteresis effect of the device is significantly reduced and the long-term stability is also improved.By optimizing the concentration,the PCE of C-PSCs achieved a maximum of 14.31%,which was improved by 20.25%compared with 11.90%of the pristine C-PSCs.This work provides a facile,environmentally friendly and efficient strategy for improving the overall performance of C-PSCs using inexpensive coal-based N-GQDs.

关键词： Carbon-basedPSCs Nitrogen-doped GQDs Reducing the defect density Nonradiative recombination

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The Origin of The Soft X-Ray Excess in the Seyfert 1.5 Galaxy ESO 362-G18

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Research in Astronomy and Astrophysics 2022年第3期22卷 10-32页

作者： Xiao-Gu Zhong jian-cheng Wang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China

We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess.The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in active galactic nuclei at present.We use the simultaneous X-ray observation data of XMM-Newton and Nu STAR on2016 September 24 to perform spectral analysis in two steps.First,we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models.Moreover,we also explore the Hybrid model,Double Reflection model and Double Warm Corona model.We find that both the Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit statistics.Second,we add the rms and covariance spectra to perform the spectral analysis with time-average spectra.The result shows that the warm corona could reproduce all of these spectra well.The hot,optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency,meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.

关键词： galaxies:active galaxies:individual(ESO 362-G18) galaxies:Seyfert

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On Absolute Uniform Retracts, Uniform Approximation Property and Super Weakly Compact Sets of Banach Spaces

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Acta Mathematica Sinica,English Series 2021年第5期37卷 731-739页

作者： Li Xin cheng Qing Jin cheng jian jian WANG School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,we show that every super weakly compact convex subset of a Banach space is an absolute uniform retract,and that it also admits the uniform compact approximation property.These can be regarded as extensio... 详细信息

关键词： Super weak compactness absolute uniform retract Banach spaces

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Transient Phenomena from Gas Erupting Neutron Stars

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Research in Astronomy and Astrophysics 2022年第1期22卷 189-191页

作者： Hui-Quan Li jian-cheng Wang Yunnan Observatories Chinese Academy of Sciences650216 KunmingChina Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences650216 KunmingChina Center for Astronomical Mega-Science Chinese Academy of Sciences100012 BeijingChina

Starquakes probably occur in rapidly spinning or ultra high field neutron stars. In this article, we argue that highly compressed gas containing electron–positron pairs could evaporate and erupt from inside the neutron star when a crack forms and then heals during a starquake. Under the influence of the existing oscillation modes of the star, the crack may have sufficiently large size and long lifetime. An appropriate amount of gas can erupt into the magnetosphere with relativistic and nearly uniform velocity, producing various transient and bursting phenomena.

关键词： stars:neutron stars:magnetars (stars:)pulsars:general

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Banach Spaces Which are Isometric to Subspaces of c_(0)(Г)

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Acta Mathematica Sinica,English Series 2021年第8期37卷 1171-1178页

作者： Li Xin cheng jian jian WANG School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China

In this paper,we give a number of characterizations for a Banach space X which is isometric to a subspace of c_(0),or,c_(0)(Г),successively,in terms of extreme points of its dual unit ball Bx*,Frechet and Gateaux der... 详细信息

关键词： Isometric embedding to c_(0) Frechet derivative Gateaux derivative extreme point Banach space

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