世界各国和地区的核学会

美国核学会(ANS)主席:A.David Rossin,24129 HillviewDrive,Los Altos Hills,CA 94024,USA;电话:(416)9487939,传真:(415)9417849,电传:4792673.执行理事:James G.Toscas,ANS,555N.Kensington Avenue,La Grange Park,IL60525,USA;电话:(708)5798200,传真:(708)5798295,电传:4792673.

1993年世界原子能科学技术会议预报(二)(5—8月)

99.国际遥控技术会议。组织者:英国核能学会5月.英国,伦敦100.1993年国际机器人学和自动化会议。范围:包括在核领域和其他危险环境中的应用5月2—7日,美国,佐治亚州,亚特兰大101.1993年激光与电子光学(CLEO)会议和量子电子学与激光科学会议(QELS)。5月2—7日,美国,马里兰州。

^(188)Re β^-衰变纲图的研究

基于前人核能测量数据,研究188Re经β-衰变到达188Os的各低激发态的能级值,及各能级间的跃迁γ分支比,各γ射线的跃迁能量和跃迁强度等.经分析筛选及用新标准重新归一,推荐最佳实验数据,对测量误差采用加权平均法确定;对没有新实验数据的,多采用SingnhB推荐数据;对衰变纲图及其衰变特性不完全自洽,推荐物理量不齐全的,用国际ENSDF评价系统,以原推荐最佳实验数据为基础进行自洽处理与理论计算.该理论计算填补了目前实验数据不足的空缺,给出了一个更合理的188Os能级结构纲图.

电子密度变化对^(56)Mn半衰期的影响

利用微型中子源反应堆辐照55Mn样品,得到放射性核素56Mn,使用高纯锗探测系统测量56Mn的能谱,得到56Mn在不同化合态下的半衰期并进行比较.通过β衰变的费米理论,引入约化电荷计算,对不同化合态下56Mn的衰变常数与约化电荷进行比对研究.利用同核异能移概念,分析原子价电子的交换和电子云的重叠对56Mn衰变常数的影响,说明56Mn半衰期会因为电子密度不同而改变.

用于无损检验的CT法

【德国《原子经济》1993年第 3期第 182页报道】德国斯图加特大学核能学和能源系统研究所(IEK)开发了一种用于无损检验的中子—计算机断层照相法(CT)。近年内,医疗中所用的CT技术日益应用于无损检验,但使用的射线多数是X线或γ射线。近几年来,IKE一直从事可视为 X线或γ CT准互补法的中子CT的研究。因为X线量子或γ量子是与原子壳层上的电子发生反应。

Supported dual-atom catalysts: Preparation, characterization, and potential applications

Developing sustainable and clean electrochemical energy conversion technologies is a crucial step in addressing the challenges of energy shortage and environmental pollution. Exploring and developing new electrocatalysts with excellent performance and low cost will facilitate the commercial use of these energy conversion technologies. Recently, dual-atom catalysts(DACs) have attracted considerable research interest since they exhibit higher metal atom loading and more flexible active sites compared to single-atom catalysts(SACs). In this paper, the latest preparation methods and characterization techniques of DACs are systematically reviewed. The advantages of homonuclear and heteronuclear DACs and the catalytic mechanism and identification technologies between the two DACs are highlighted. The current applications of DACs in the field of electrocatalysis are summarized. The development opportunities and challenges of DACs in the future are prospected. The ultimate goal is to provide new ideas for the preparation of new catalysts with excellent properties by customizing diatomic catalysts for electrochemical applications.

Effect of annealing temperature on microstructure and mechanical properties of cold-rolled commercially pure titanium sheets

The strength of traditional commercially pure titanium(CP-Ti) alloys often fails to meet the demand of structural materials. In order to enhance their mechanical properties, the cold-rolled CP-Ti alloys were annealed at different temperatures, and the recrystallization behavior and texture evolution were investigated. It was found that the bimodal microstructure(equiaxed and elongated grains) was formed after partial recrystallization, and the corresponding sample exhibited an excellent combination of ultimate tensile strength(702 MPa) and total elongation(36.4%). The recrystallization nucleation of CP-Ti sheets occurred preferentially in the high strain and the high-angle grain boundaries(HAGBs) regions. Meanwhile, the internal misorientations of the deformed heterogeneous grains increased and transformed into HAGBs, which further promoted the recrystallization nucleation. The main recrystallization texture was basal TD-split texture transformed from cold-rolled basal RD-split texture, and the oriented nucleation played a dominated role during recrystallization.

Friction stir welding of aluminum to copper—An overview

Components made by joining different materials are required in various engineering applications.Fabrication of suchcomponents is a challenging task due to the vast difference in mechanical,thermal and electrical properties of the materials beingused.Friction stir welding(FSW)is capable of joining dissimilar materials such as aluminum(Al)and copper(Cu)and thereforeresearchers have used this novel process for dissimilar joining.Consequently,several works pertaining to dissimilar joining,specifically Al?Cu,are available in the literature but they are scattered in different sources,which makes the task of gatheringinformation about dissimilar FSW of Al?Cu cumbersome.This work has been written with an aim to provide all pertinentinformation related to dissimilar FSW of Al?Cu at one place to ease the problems of researchers.It comprehensively covers andsummarizes the topics such as the effect of tool design and geometry,FSW process parameters,FSW strategies on mechanicalproperties,microstructure and formation of defects during dissimilar FSW of Al?Cu.In addition,it also presents and discussesseveral variants of dissimilar FSW of Al?Cu.Finally,this work not only puts forth major findings of the previous researchers but alsosuggests future recommendations for dissimilar FSW of Al?Cu.

Effect of temperature on copper corrosion in high-level nuclear waste environment

The effect of temperature on the corrosion behavior of copper in simulated high-level nuclear waste environment wassystematically studied.Electrochemical methods,including electrochemical impendence spectra,Mott–Schottky technology,cyclicpolarization,and potentiostatic polarization,were employed to characterize the corrosion behavior of copper at different temperatures.Stereoscopic microscopy and scanning electron microscopy were used to examine the surface morphology,and X-ray photoelectronspectroscopy analysis was used to identify the composition of the passive film.The experimental results show that corrosionresistance of the passive film does not blindly decrease with the increase of temperature but increases at60°C owing to a compactouter layer;there is a potential for pitting corrosion,which decreases as the temperature increases.The main product of copper in ananaerobic aqueous sulfide solution is Cu2S but the content of CuS increases at higher temperatures.The whole passivation rangeshows p-type semiconductor characteristics and the magnitude of the acceptor density is1023cm-3,which increases with increasingtemperature.

Study on the resistance spot welding technology of 22MnMoB hot stamping quenched steel

In this paper, the spot welding technology of a new kind of 22MnMoB hot stamping quenched steel sheet was systematically studied by power frequency spot welder. Through a series of technology and test experiments, we have obtained the optimal spot welding technological parameter condition. According to the results, the relations among spot welding technological parameter, welding nugget, mechanical property and fracture mode were discussed. The effects of all the welding parameters such as welding current, welding time and electrode force on the quality of joint can be boiled down to one thing--the diameter of welding nugget. The experimental results showed that welding nugget diameter determines the mechanical property of spot welding joint and the relation between welding nugget diameter and the mechanical property of joint presents a kind of linear mathematic representation. There are two typical fracture models of 22MnMoB hot stamping quenched steel sheet, i.e., interracial fracture and nugget pullout. Other than mild steel or normal high strength steel, in the shearing tensile test, hot stamping quenched steel has a great tendency to fail in interfacial mode due to the effects of high strength matrix structure, welding soft zone and the porosity level of fusion zone.

Effect of duplex aging on microstructure and mechanical properties of near-βtitanium alloy processed by isothermal multidirectional forging

The effects of sub-transus(α+β)annealing treatment(ST),followed by single aging(SA)or duplex aging(DA)on the microstructural evolution and mechanical properties of near-βTi-4Al-1Sn-2Zr-5Mo-8V-2.5Cr(mass fraction,%)alloy were investigated using optical microscopy,scanning electron microscopy,and transmission electron microscopy.The results show that the finer secondaryαphase precipitates in the alloy after DA than SA(e.g.,149 nm for SA and 69 nm for DA,both after ST at 720℃).The main reason is that the pre-aging step(300℃)in the DA process leads to the formation of intermediateωphase nanoparticles,which assist in the nucleation of the acicular secondaryαphase precipitates.In addition,the strength of the alloy after DA is higher than that of SA at the specific ST temperature.A good combination is achieved in the alloy subjected to ST at 750℃,followed by DA(UTS:1450 MPa,EL:3.87%),which is due to the precipitation of nanoscale secondaryαphase by DA.In conclusion,DA is a feasible process for this new near-βtitanium alloy.

Properties of Unsymmetrical Parabolic Confinement Potential Quantum Dot Qubit

On the condition of electric-LO phonon strong coupling in unsymmetrical parabolic confinement potential quantum dot （QD）, we obtain the eigenenergies of the ground state and the first-excited state, the eigenfunctions of the ground state, and the first-excited state by using variational method of Pekar type. This system in QD may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground state and the first-excited state, we obtain the time evolution of the electron density. The relations both the probability density of electron and the period of oscillation with the electron-LO-phonon coupling strength, the confinement strengths in the xy-plane and the z-direction are discussed.

Effect of Superstrong Magnetic Fields on Nuclear Energy Generation Rate in the Crust of Neutron Stars

This paper shows that superstrong magnetic fields （such as those of magnetars） can increase the energy generation rate many times in the crust of neutron stars. This result undoubtedly not only influences the cooling of neutron stars and the X-ray luminosity observed of neutron stars but also the evolution of neutron stars.

Mechanical Properties of Sunflower Seed and Its Kernel, Azargol Variety as a Case Study, under Compressive Loading

The objective of this study was to investigate the effect of moisture content, size and loading orientation on mechanical properties such as force, deformation and energy absorbed per unit volume for fracturing Iranian sunflower seed and its kernel （Azargol as a case study） under quasi-static loading. Sunflower seeds and their kernels were quasi-statically loaded in horizontal and vertical orientations with moisture content in three levels： 3%, 7% and 14%, and size category in three levels： small, medium and large. The obtained results showed that rupture force for both sunflower seed and its kernel decreased with increasing moisture content while the absorbed energy and deformation at rupture point increased for all size categories in both horizontal and vertical loading orientations. Also, seeds in the vertical orientation developed hull cracks at a higher level of force than those loaded in the horizontal orientation. However, for the kernels it was the opposite. In addition, the average forces required to cause kernel rupture were lower （11.64-39.9 N） than those required to rupture the seed （30.06-117.46 N） in both orientations. Seeds loaded in a vertical orientation absorbed more energy （87.67 mJ） prior to rupture than those loaded in the horizontal （46.60 mJ） orientation. However, for the kernels it was the opposite.

PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (III)-ADSORPTION ON MODIFIED ACTIVATED CARBON FIBER

Structures of a series of activated carbon fibers were modified by impregnating them with organic and inorganic materials such as Methylene blue(Mb)、p-nitrophenol (PNP)、NaCl or by oxidizing with KMnO4 or HNO3. The influence of pore filling or chemical treatment on their xenon adsorption properties was studied. The experimental results show that Mb and PNP filling of activated carbon fibers result in the decrease of xenon adsorption capacities of these treated ACFs, which is due to the decrease of their surface area and micro-pore volume. However, the adsorption capacity increases greatly with oxidizing treatment of activated carbon fibers by 7mol/L HNO3.

First Exploration on The Reform of Experimental Examination of Physiology in Higher Vocational College Students

Objective：The purpose of this paper is to explore the application effect of diversified assessment mode in physiology experimental examination of higher vocational college students.Method：We selected 173 higher vocational college students as the research group,in the experimental assessment,adopted diversi？ ed assessment model;and selected 192 higher vocational college students as the control group,adopted the traditional assessment method.The pathological examination scores of the two groups were compared,and the research group was investigated by questionnaire.Result：The physiological end term test scores （t=1.973,p〈0.05） and experimental operation assessment scores of the research group were higher than those of the control group （t=1.624,p〈0.05）.The diversified assessment model helps to improve the learning initiative,improve learning interest,foster collaboration and communication ability,reduce learning pressure and reduce anxiety before examination.Conclusion：The diversified assessment model can highlight the cultivation of professional skills and innovation ability,enable students reserve the necessary knowledge through inquiry and cooperative learning,and conducive to sustainable development of students.B

Estonia： The Prospects of Nuclear Energy

This paper details the prospects for a civil nuclear power station in Estonia. Due to its climate change commitments, Estonia needs a new source of electricity provision. There is little academic literature on Estonia, and this research builds upon previous work but is more detailed in its analysis with primary data included in the form of interviews with Estonian energy industry experts. All the conditions that have led to nuclear energy being considered as an option are assessed, along with why it represents the most strategic path for Estonia in terms of electricity provision. Through the interview analysis a framework is established and advanced for the successful initiation of a national nuclear power plant project. This research is therefore of high value for small EU countries who intend to consider nuclear energy as an option in their energy mix or have more advanced plans to develop a nuclear program.

An XPS Study of Nitrogen Structures in Soil Humic Substances

X-ray photoelectron spectroscopy (XPS) was applied to examine the N structures of soil humic substances and some of their analogues. It was found that for soil humic substances XPS method gave similar results as those obtained by 15N CPMAS NMR (cross-polarization magic-angle spinning nuclear magnetic resonance) method. 70%～86% of total N in soil humic substances was in the form of amide, and 6%～13% was presented as amines, with the remaining part as heterocyclic N. There was no difference in the distribution of the forms of N between the humic substances from soils formed over hundreds or thousands of years and the newly formed ones. For fulvic acid from weathered coal and benzoqu inone- (N H-4 )-2 S O-4 polymer the XPS results deviated significantly from the 15N CPMAS NMR data.

Ethical Perspective on Turkish Environmental Impact Assessment for Nuclear Energy

In 2013, The Turkish Ministry of Environment and Urban Planning issued four thousand pages of a cut and paste Environmental Impact Assessment （EIA） report for the Akkuyu nuclear power plant and nuclear fuel fabrication complex project located on Turkey＇s Mediterranean coastline, in the Mersin providence, which will be built on a build-own-operate basis by Russian company Rosatom. Numerous complaints have already been filed against the EIA, challenging the scientific integrity of the report on the following grounds： misrepresentation of failure to specify the radioactive inventory and of projected releases into the environment, omitting tritium and carbon-14; incomplete information about the toxic chemicals which will be injected into the cooling system throughout the nuclear complex; misleading information about the cooling water＇s temporal and chemical effects on marine life; lack of details on an emergency evacuation plan; lack of a comprehensive nuclear waste management plan; unspecified insurance coverage for the nuclear complex, noncompliance with third party liability requirements. Coupled with these complaints are allegations that signatures on some sensitive reports contained or referred to have been falsified.