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Impact of connected and autonomous vehicles on traffic safety of mixed traffic flow:from the perspective of connectivity and spatial distribution

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transportation Safety and Environment 2022年第3期4卷 88-97页

作者： Jiakuan Dong Jiangfeng Wang Dongyu Luo Key Laboratory of transport Industry of Big Data Application Technologies for Comprehensive transport of Ministry of transport Beijing Jiaotong UniversityBeijing 100044China.

Equipped with high driving automation and advanced communication technologies, connected and autonomous vehicles (CAV) areexpected to possess a shorter reaction time and a wider vision,which are promising to improve traffic safety and efficiency. However,little attention has been paid to the effect of connectivity and spatial distribution on the safety performance of mixed traffic flow. Inthis paper, we attempt to investigate the impact of CAV on traffic safety considering these factors. To this end, a car-following modelfor CAV is proposed first. Then, the cooperative driving strategy for CAVs is designed. Precisely, the feedback gains of the informationare adjusted in real-time and are designed based on the derived stability criterion of the mixed traffic flow. Microscopic simulations ofmixed traffic flow in traffic oscillation are designed and conducted to explore how the distribution and connectivity of CAV affect thesafety performance ofmixed traffic flow. Simulation results show that increasing the penetration rate of CAV is promising to shift thesafety performance ofmixed traffic flow. In addition, the safety performance of mixed traffic flow is related to the spatial distributionand communication range of CAV. Besides, increasing communication range does not inevitably improve the safety performance ofmixed traffic flow when the penetration rate of CAV is low. Moreover, it is also found from the spatial–temporal trajectory of themixedtraffic flow that introducing CAV can mitigate the propagation of the stop-and-go wave and increase the throughput.

关键词： Mixed traffic traffic safety connected and autonomous vehicle connectivity spatial distribution

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Interaction of land Demand and Supply Effects in Intensive land Use: a Simulation Study for Chengdu,China

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Journal of Donghua University(English Edition) 2015年第4期32卷 636-641页

作者：辜寄蓉陈先伟江浏光艳杨海龙于有翔 Key Laboratory of land Resources Evaluation and Monitoring in Southwest The Bureau of land and Resources of Chengdu

Intensive land use( ILU) policies affect the demand and supply of land. These policies promote efficient land use, and demands for land must therefore be evaluated in terms of the level of land-use intensity. If the demand is considered excessive, ILU policies act like a "valve"to restrict the land supply. Drawing on data from Chengdu,China,where developable land is scarce,we construct a model using system dynamics( SD) to simulate two scenarios: ILU development and non-ILU development. The results show that when ILU leads to positive land-use efficiency,land supply will exceed demand,resulting in an appropriate level of real demand for the current population level and GDP. Thus,artificial demand( inflated by investors) is reduced. By contrast,when non-ILU leads to negative land-use efficiency,land demand will exceed supply. In this scenario,artificial demand is higher than real demand.

关键词： land demand and supply intensive land use(ILU) developable land land area system dynamics(SD)

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K^+ retention in leaf mesophyll, an overlooked component of salinity tolerance mechanism:A case study for barley

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Journal of Integrative Plant Biology 2015年第2期57卷 171-185页

作者： Honghong Wu Min Zhu Lana Shabala Meixue Zhou Sergey Shabala School of land and Food University of Tasmania

Plant salinity tolerance is a physiologically complex trait, with numerous mechanisms contributing to it. In this work, we show that the ability of leaf mesophyll to retain K＋ represents an important and essentially overlooked component of a salinity tolerance mechanism. The strong positive correlation between mesophyll K＋ retention ability under saline conditions （quantified by the magnitude of NaCl-induced K＋ efflux from mesophyll） and the overall salinity tolerance （relative fresh weight and/or survival or damage under salinity stress） was found while screening 46 barley （Hordeum vulgare L.） genotypes contrasting in their salinity tolerance. Genotypes with intrinsically higher leaf K＋ content under control conditions were found to possess better K＋ retention ability under salinity and, hence, overall higher tolerance. Contrary to previous reports for barley roots, K＋ retention in mesophyll was not associated with an increased H＋-pumping in tolerant varieties but instead correlated negatively with this trait. These findings are explained by the fact that increased H＋ extrusion may be needed to charge balance the activity and provide the driving force for the high affinity HAK/KUP K＋ transporters required to restore cytosolic K＋ homeostasis in salt-sensitive genotypes.

关键词： Cytosolic K+ homeostasis ion flux membrane potential membrane transport tissue tolerance

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Geology and Mineral Chemistry of Uranium-and Thorium-bearing Minerals in Rare-Metal(NYF)Pegmatites of Um Solimate,South Eastern Desert,Egypt

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Acta Geologica Sinica(English Edition) 2021年第5期95卷 1568-1582页

作者： Mohamed A.ALI Ahmed E.ABDEL GAWAD Mohamed M.GHONEIM Nuclear Materials authority 530 El-MaadiCairoEgypt

The garnet muscovite granitic pegmatite of Um Solimate,in southern Egypt,represents a promising asset for strategic and economic metals,especially Bi-Ni-Ag-Nb-Ta as well as U and *** ore bodies occur as large masses,pockets and/or veins of very coarse-grained pegmatites,which consist mainly of K-feldspar,quartz and albite with subordinate muscovite,garnet,and *** data revealed that e U-and e Th-contents of the pegmatites reach up to 39 ppm and 82 ppm,*** studied pegmatites are enriched in primary U and Th minerals(uraninite,coffinite,thorianite and uranothorite)as well as Hf-rich zircon and monazite,which give rise to anomalous radioactive ***-tantalium-bearing minerals(***,microlite and uranopyrochlore),xenotime,barite,galena,fluorite,and apatite are ubiquitous,and,consequently,the studied pegmatites belong tothe Niobium-Yttrium-Fluorine-type(NYF)*** noble metal mineralization includes argentite(Ag_(2)S),native Ni and Bi as well as bismite and *** addition,beryl and tourmaline are observed in pegmatites near the contact with metasediments and ultramafic *** observed compositional variations of Ta/(Ta+Nb)and Mn/(Mn+Fe)ratios in columbite(0.08-0.45 and 0.11-0.57,respectively)and Hf contents in zircon(3.54-6.46 wt%)may reflectan extreme degree of magmatic fractionation leading to formation of the pegmatite orebody.

关键词： radioactivity rare-metal mineralization pegmatites U/Th-bearing minerals Um Solimate Egypt

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Performance evaluation of open-graded epoxy asphalt concrete with two nominal maximum aggregate sizes

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Journal of Central South University 2015年第11期22卷 4483-4489页

作者：罗桑钱振东薛永超 Intelligent transport System Research Center Southeast University

Open-graded friction course(OGFC) is applied to pavement surfaces to increase driving safety under wet conditions, and recently, to reduce tire/pavement noise. The durability of OGFC, however, has been a concern since conventional OGFC mixes last typically less than ten years before major maintenance or rehabilitation is needed. This work investigates a new open-graded asphalt mixture that uses epoxy asphalt as binder to improve mix durability. One type of epoxy asphalt that has been successfully applied to dense-graded asphalt concrete for bridge deck paving was selected. A procedure of compacting the mix into slab specimens was developed and a series of laboratory tests were conducted to evaluate the performance of the new mix, including Cantabro loss, permeability, friction, shear strength, and wheel rutting tests. Results show superior overall performance of the open-graded epoxy asphalt mix compared to conventional open-graded asphalt mix. There are also preliminary indications that the OGFC mix with 4.75-mm NMAS gradation can improve the resistance performance to raveling, while the OGFC mix with 9.5-mm NMAS gradation can improve the performance of surface friction at a high slip speed.

关键词： open-graded concrete epoxy asphalt concrete nomina

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Effects of the phase variation and high-order momentum transfer components of NN amplitude on p-~4He elastic scattering

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Nuclear Science and Techniques 2018年第1期29卷 65-76页

作者： I.M.A.Tag-Eldin M.M.Taha S.S.A.Hassan Nuclear Experimental Physics Department Nuclear Research Center Atomic Energy Authority Mathematics and Theoretical Physics Department Nuclear Research Center Atomic Energy Authority

Elastic scattering differential cross sections for a p- ~4He system are calculated within the framework of optical limit approximation of the Glauber multiple scattering model. Three different ranges for proton energy(E_(lab)), 19〈E_(lab)〈50 Me V, 100≤E_(lab)≤1730 Me V, and 45 ≤E_(lab)≤393 Ge V are considered. It is shown that the Pauli blocking fails to describe the data up to the proton energy, E_(lab)〈100 Me V. For higher proton energies, a qualitative agreement is obtained. The observed elastic scattering differential cross section is nicely reproduced in the whole range of scattering angles in the center of mass system up to Θ_(c.m.)〈200° for 19〈E_(lab) ≤100 Me V when the effect of both the nucleon–nucleon(NN) phase variation parameter γNN and higher-order momentum transfer components(λ_n; n = 1 and 2) of(NN) elastic scattering amplitude is included. In the range of 200 E_(lab) 1730 Me V, introducing λ_n plays a significant role in describing the data up to the momentum transfer, q^2≤1:2(Ge V/c)~***, it is found that considering only the effect of phase variation parameter, cNN, improved the agreement in the region of minima for elastic scattering differential cross section for 45≤E_(lab)≤393 Ge V. The values of cNNand kn as a function of incident proton energies are presented.

关键词： Elastic scattering Optical limit approximation Glauber multiple scattering model

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Adhesion at friction and wear

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Friction 2022年第11期10卷 1859-1878页

作者： Dmitry P.MARKOV Research Institute of Railway transport Moscow 129851Russia

Our understanding of the surrounding world,from friction to the origin of life,depends on how we imagine the contact interaction of condensed *** are the forces acting in contact with solids?Do they attract(adhesive)or repel(dehesive)?Theory and research at the atomic–molecular level have shown that the force are adhesive,but everyday experiences cast doubt on this *** article addresses this issue by considering the mistakes made in experimental and theoretical tribology and surface *** into account the theories of hybridization and dehybridization of electron orbitals and valence bonds,the views on the structure of the surfaces of condensed bodies and the force arising during contact interaction are *** influence of van der Waals,hydrogen,covalent,metallic,and ionic bonds on the properties of lubricants is *** contours of the dehesive–deformation theory of friction and wear are also outlined.

关键词： atomic and molecular interactions adhesion cohesion dehesion friction wear

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DEM speedup: Stiffness effects on behavior of bulk material

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Particuology 2014年第1期12卷 107-112页

作者： Stef Lommen Dingena Schott Gabriel Lodewijks Department of Maritime and transport Technology Delft University of Technology

A number of techniques exist for minimizing the computational cost of discrete element simulations （DEMs）. One such method is a reduction of particle stiffness, which allows for bigger time steps and therefore fewer iterations in a simulation. However, the limits and drawbacks of this approach are still unclear, and may lead to invalid results. This paper investigates the effect of a stiffness reduction on bulk behavior by examining three case studies. Two cases demonstrate that particle stiffness can be reduced without affecting the bulk material behavior, whereas the third test shows that a stiffness reduction influences the bulk behavior.

关键词： Discrete element methodSpeedupStiffness reductionLimitOverlap

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Separation of ^(152+154)Eu,^(90)Sr from radioactive waste effluent using liquid–liquid extraction by polyglycerol phthalate

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Nuclear Science and Techniques 2018年第6期29卷 76-84页

作者： M.F.Attallah S.E.Rizk S.A.Shady Analytical Chemistry and Control Department Hot Laboratories Center Atomic Energy Authority of Egypt Chemistry of Nuclear Fuel Department Hot Laboratories Center Atomic Energy Authority of Egypt Technology of Nuclear Fuel Department Hot Laboratories Center Atomic Energy Authority of Egypt

A new polyglycerol phthalate extractant was prepared and characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance(~1H NMR) spectroscopy, and thermogravimetric analysis. A preliminary study of the extraction of long-lived(^(90) Sr and ^(152+154)Eu) and short-lived(^(90) Y) radionuclides by polyglycerol phthalate was performed. The influence of different diluents, concentration of the acid, type of acid, and various interfering ions was explored. The stripping of ^(152+154)Eu radionuclide was studied by using different acid solutions, and it was found that sulfuric acid was the ideal acid for this purpose. Furthermore,^(152+154)Eu was extracted from the fission products(^(90) Sr) and the extraction% of^(90) Sr was found to improve in the presence of interfering ions.

关键词：放射性核种抽取液体 Fourier 分离浪费光谱学 NMR

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Impact of wastewater reuse on cobalt status in Egyptian environment

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Journal of Environmental Sciences 2003年第3期15卷 388-395页

作者： M.F. Abdel-Sabour Soil and Water Research Department Nuclear Research Center Atomic Energy Authority

Cobalt is used in the manufacture of alloys, catalysts in the petroleum industry, catalytic converters, and paint pigments. Thus the potential for Co releases into the environment is highly increased. Use of waste sludges and sewage effluent to fertilize and irrigate soils has also increased soil Co concentrations. Total cobalt contents of alluvial delta soil of Egypt show considerable variation ranging from 13.1 to 64.7 ppm. The impact of either wastewater irrigation or industrial activities on soil total Co was obvious due to accumulation of organic matter and solid waste in the surface soil samples. Food crops and vegetables should not be grown on soil highly contaminated by Co. It is noteworthy that the delayed neutron activation analysis(DNAA) technique could be used successfully for total Co determination due to its high sensitivity. It is quit clearly that dust samples of Cairo City contains higher Co level, as compared to Suez Canal Region(Ismailia, Port Said and El-Suez cities). The high values in Cairo City may be due to the existence of industries around the city and the intensive traffic. To minimize Co environmental hazards, waste effluents should be treated on site. Thus, levels of potentially toxic Co needs to be continuously monitored and should be removed during several treatment processes before the disposal of these wastes.

关键词： cobalt environment Egypt

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