检索结果-南通市图书馆

Environmental impact of radionuclide migration in groundwater from a low intermediate level radioactive waste repository

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第2期13卷 180-184页

作者： wang, Jin-sheng Yang, zhi-feng Li, Shu-shen wang, zhi-ming Institute of Environmental Sciences Beijing Normal UniversityState Key Joint Laboratory of Environmental Simulation and Pollution Control Beijing 100875 China China Institute for Radiation Protection Taiyuan 030006 China

The radionuclide migration from a certain Chinese repository with low-intermediate level radioactive solid waste is studied. The migration in groundwater is analyzed and computed in detail. Under presumption of normal releasing, or the bottom of the repository has been marinated for one month with precipitation reaching 600 mm once and a 6 m aerated zone exists, a prediction for 7 radionuclides is conducted. It shows that the aerated zone is the primary barrier for migration. The migration for radionuclides 60Co, 137Cs, 90Sr, 63Ni, etc. will be retarded in it within 500 years. The concentration of 239Pu will be decreased by amount of 6 order. Only 3H and 14C can migrate through the aerated zone. The radionuclides that go through the aerated zone and enter the aquifer will exist in spring, stream and sea. Based on this, the intake dose by residents in different age group resulting from drinking contaminated spring water, eating seafood is calculated. The results showed that the impact of the repository to the key resident group is lower than the limit in national repository regulation standard. This complies with the repository management target.

关键词： intermediate level radioactive waste repository Environmental impact of radionuclide migration in groundwater from a low

Suppression of super-knock in TC-GDI engine using two-stage injection in intake stroke(TSII)

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2014年第1期57卷 80-85页

作者： wang zhi XU YaQi wang JianXin State Key Laboratory of Automotive Safety and Energy Tsinghua University

Turbocharging and direct injection are main technologies used for energy-saving gasoline engines. But the biggest challenge is super-knock, whose mechanism is unclear and has no effective strategy to suppress this super-knock until now. The effects of injection strategies on super-knock were experimentally investigated in a turbocharged GDI engine. It was found that two-stage injections during intake stroke （TSII） can eliminate super-knock. Meanwhile, the fuel consumption, emissions and exhaust tem- perature can keep optimized level. By sweeping the start of the 1st injection （SOIl）, end of the 2nd injection （EOI2） and the split injection ratios （ROI2） using 5000 cycles evaluation test at low-speed high load operating point, the optimized injection strategy for the typical TC-GDI engine is TSII with SOIl at middle of intake stroke, EOI2 at end of intake stroke, and ROI2 of 0.3.

关键词： turbocharged GDI engine super-knock injection strategies two-stage injections in intake stroke (TSII)

Effects of the types of overlap on the mechanical properties of FSSW welded AZ series magnesium alloy joints

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2012年第3期19卷 231-235页

作者： Dan wang Jun Shen Lin-zhi wang School of Materials Science and Engineering Chongqing UniversityChongqing 400044China

The effects of the types of overlap on the mechanical properties of the friction stir spot welding （FSSW） welded AZ series magnesium alloy joints were investigated by microstructural observations, microhardness tests, and tensile tests. The results show that the microstructure of the stir zone adjacent to the periphery of the rotating pin is mainly composed of the upper sheet. The average distance D between the longitudinal segment of the curved interface and the keyhole periphery, the tensile shear force, and the microhardness of the stir zone of the FSSW welded AZ61 alloy joint are the highest in all samples. During FSSW of AZ31 and AZ61 dissimilar magnesium alloys, the irregular deformation of the longitudinal segment of the curved interface appears, while the microhardness of the stir zone is higher when AZ61 alloy is the upper sheet. Moreover, the microhardness of the stir zone increases initially and then decreases sharply in the longitudinal test position.

关键词： magnesium alloys friction stir welding microstructure microhardness tensile properties

Solving the Nonlinear Variable Order Fractional Differential Equations by Using Euler Wavelets

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第2期118卷 339-350页

作者： Yanxin wang Li Zhu zhi wang School of Science Ningbo University of TechnologyNingboChina.

An Euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this *** properties of Euler wavelets and their operational matrix together with a family of piecewise functions are first *** they are utilized to reduce the problem to the solution of a nonlinear system of algebraic *** the convergence of the Euler wavelets basis is *** method is computationally attractive and some numerical examples are provided to illustrate its high accuracy.

关键词： Euler wavelets variable order fractional differential equations caputo fractional derivatives operational matrix convergence analysis.

Illuminating Neural Circuits in Alzheimer’s Disease

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2021年第8期37卷 1203-1217页

作者： Yang Ying Jian-zhi wang Department of Pathophysiology School of Basic MedicineMinistry of Education Key Laboratory for Neurological DisordersHubei Key Laboratory for Neurological DisordersTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

Alzheimer’s disease(AD)is the most common neurodegenerative disorder and there is currently no *** circuit dysfunction is the fundamental mechanism underlying the learning and memory deficits in patients with ***,it is important to understand the structural features and mechanisms underlying the deregulated circuits during AD progression,by which new tools for intervention can be ***,we briefly summarize the most recently established cutting-edge experimental approaches and key techniques that enable neural circuit tracing and manipulation of their *** also discuss the advantages and limitations of these ***,we review the applications of these techniques in the discovery of circuit mechanisms underlyingβ-amyloid and tau pathologies during AD progression,and as well as the strategies for targeted AD treatments.

关键词： Neural circuit Alzheimer’s disease Single cell RNA sequencing Neural circuit tracing Optogenetics Chemogenetics

Selective Laser Melting of 30CrMnSiA Steel: Laser Energy Density Dependence of Microstructural and Mechanical Properties

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2018年第8期31卷 807-814页

作者： Lin-zhi wang Wen-Hou Wei Chongqing Key Laboratory of Additive Manufacturing Technology and Systems Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences

Three-dimensional parts of the 30 CrMnSiA steel were successfully fabricated using selective laser melting（SLM）. The microstructures and mechanical properties of the SLM-processed 30 CrMnSiA samples were investigated by scanning electron microscope and transmission electron microscopy. The results indicate that the microstructures of the 30 CrMnSiA samples consist mainly of lath martensite and acicular martensite. The value of the surface roughness decreases with increasing laser energy density（LED） before it reaches a minimum and then increases with further increasing LED. The relative density, microhardness and ultimate tensile strength of the SLM-processed samples initially increase and then decrease with increasing LED. By taking the relative density, surface roughness, microhardness and ultimate tensile strength into account, the optimized LED should be in the range of 46.15–51.28 J mm^（-3） for the SLM-processed30 CrMnSiA alloys. In addition, the differences in the microstructures and mechanical properties between the conventionally wrought 30 CrMnSiA sample and SLM-processed 30 CrMnSiA samples were also studied.

关键词： 30CrMnSiA Selective laser melting Laser energy density Microstructure Mechanical properties

Analysis of Vector Meson Transitions Among Heavy Quarkonium States

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2012年第1期57卷 93-101页

作者： wang zhi-Gang Department of Physics North China Electric Power UniversityBaoding 071003China

In this article,we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in a systematic way,and make predictions for the ratios among the vector meson decay widths of a special multiplet to another *** predictions can be confronted with the experimental data in the future.

关键词： charmonium states bottomonium states vector meson transitions

Relationship between seismic structures and the diverse rupture processes of the 2023 Türkiye earthquake doublet

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第9期67卷 2810-2823页

作者： zhi wang Yi FU Shunping PEI CAS Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Recent geodetic and seismological observations of two major earthquakes in southeastern Türkiye in February 2023 have revealed complex rupture initiation,propagation,and segmentation along the East Anatolian Fault Zone(EAFZ)and surrounding ***,the role of upper crust structures along the EAFZ in determining the diverse rupture processes of this earthquake doublet remains *** further investigate this,we employed double-difference location and seismic tomography techniques to determine high-resolution seismic velocities(V_(P),V_(S))and Poisson’s ratio(σ)structures using a multiparameter joint tomographic *** dataset includes 100,833 high-quality source-receiver travel-time pairs of P-and *** find that the unique rupture processes of this earthquake doublet were primarily influenced by contrasting crustal seismic structures and localized geological *** M_(w)7.8 mainshock was initiated within a transitional edge zone characterized by a rigid part(asperity)of the seismogenic zone with sharp contrast variations in rock strength ranging from low to high along the *** comparison,the M_(w)7.6 rupture originated in a ductile belt featuring fluid saturation with low-VP,low-VS,and high-σvalues that extended parallel to the Cardak *** pronounced contrast structures observed along the former rupture can be attributed to the oblique collision system between the weakened section of the east Anatolian plateau and the brittle Arabian platform,while the latter rupture was initiated within the ductile structure associated with fluid intrusion caused by the northward subduction of the Cyprus slab and subsequent ***,the occurrence of the first earthquake(E1)serves to alleviate shear stress on the second earthquake(E2)fault,potentially impeding the initiation of an E2 *** the contrary,this event also significantly reduces the normal stress acting on the E2 fault due to a double left-lateral strike-slip system

关键词： 2023 Turkiye earthquake doublet Joint seismic tomography Tomographic transition edge Seismic rupture process Strong fault coupling

同方期刊数据库

High resolution observations of the 6cm H_2CO maser in NGC 6240

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2013年第3期13卷 270-276页

作者： Jun-zhi wang zhi-Yu Zhang Yu Gao School of Astronomy and Space Science Nanjing University Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education Purple Mountain Observatory Chinese Academy of Sciences Max-Planck-Institut für Radioastronomie Graduate University of Chinese Academy of Sciences

We present high resolution （- 1″） H2CO maser and 5 GHz radio continuum observations toward nearby merging galaxy NGC 6240 made with the Very Large Array in an A configuration. Two concentrations of H2CO emission at about a 6or level have been detected, one of which is associated with the strongest CO peak in the overlap region while the other is about 2″ southwest of the southem galaxy. Both H2CO concentrations are associated with near infrared H2 emission, which is thought to be from shocked molecular gas. The total H2CO line luminosity in NGC 6240 is about 60% of that in Arp 220. Based on the distribution of H2CO emission in NGC 6240, which has both active galactic nuclei and an extreme starburst, the H2CO megamaser is likely to be related to the effect of the starburst instead of nuclear activity. Radio continuum cannot be the inversion mechanism of H2CO megamasers, because the two H2CO concentrations in NGC 6240 are not associated with radio continuum emission. Instead, with the association of near infrared H2 emission, shock dynamics may produce the inverted population of H2CO needed to generate megamasers.

关键词： galaxies: ISM -- galaxies: kinematics and dynamics -- galaxies: individual (NGC 6240)