共查询到20条相似文献,搜索用时 23 毫秒
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《中国核科技报告》1989,(Z1)
In 1987 and 1988,CNDC involved many activities.Mainly they are: ·1988.4.8~15,“Nuclear Data Measurement and Evaluation Symposium”,Sichuan University.Exchanged the progress in nuclear data measurements andreviewed some of evaluation data.Also introduced the international developmentand arranged the future work. 相似文献
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M.J. HackettR. Siegele F. El-AssaadJ.A. McQuillan J.B. AitkenE.A. Carter G.E. GrauN.H. Hunt D. CohenP.A. Lay 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(20):2260-2263
The cerebral biochemistry associated with the development of many neurological diseases remains poorly understood. In particular, incomplete understanding of the mechanisms through which vascular inflammation manifests in tissue damage and altered brain function is a significant hindrance to the development of improved patient therapies. To this extent, a combination of spectrometric/spectroscopic mapping/imaging methods with an inherent ability to provide a wealth of biochemical and physical information have been investigated to understand further the pathogenesis of brain disease.In this study, proton-induced X-ray emission (PIXE) mapping was combined with scanning transmission ion microscopy (STIM) mapping and Fourier-transform infrared (FTIR) imaging of the same tissue sample to study directly the composition of the murine (mouse) cerebellum. The combination of the elemental, density and molecular information provided by these techniques enabled differentiation between four specific tissue types within the murine cerebellum (grey matter, white matter, molecular layer and micro blood vessels). The results presented are complementary, multi-technique measurements of the same tissue sample. They show elemental, density and molecular differences among the different tissue types. 相似文献
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Based on the increase in the covalent component of a bond with reduction in temperature in crystalline modifications of uranium, neptunium and plutonium, a new idea is put forward for the structure of - and -plutonium. The crystalline structure of these modifications is considered as the result of a comparatively small deviation from the ideal face-centered lattice under the action of four covalent bonds. This idea makes it possible to explain a number of anomalous properties of - and -plutonium, in particular the negative values of the volume coefficient of thermal expansion and the high values of the atomic volume. 相似文献
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Xi-Yang Wang Hong-Yu Zhang De-Qing Fang Wan-Bing He Xiao-Long Wang Qi-Bin Zheng Shi-Ming Zou 《核技术(英文版)》2023,(11):97-106
Considering the R&D for upgrading the K0L and μ detectors in the Belle II experiment using a scintillator and silicon photomultiplier(SiPM), we designed a compact high-speed and low-noise preamplifier. The preamplifier demonstrated a good gain stability, bandwidth of 426 MHz, baseline noise level of σ ≈ 0.6 mV, dynamic range of up to 170 mV of the input signal amplitude, good time resolution of 20 ps, and it can be comprehensively applied to SiPMs. Adopting pole-zero-ca... 相似文献
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T V Prevenslik 《核技术(英文版)》1996,(1)
Sonoluminescenceandcoldfusion¥TVPrevenslik(2EGreeneryCourt,DiscoveryBay,HongKong)Abstract:Atheoryofsonoluminescence(SL)propos... 相似文献
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TVPrevenslik 《核技术(英文版)》1996,7(1):1-5
A theory of sonoluminescence(SL) proposed asserts bubbles collapse in a pancake shape almost isothermally at constant volume.SL induced hot fusion at -10^7℃is most likely impossible.By the proposed theory,the bubbles are treated as miniature IRasers with the dimension between pancake faces equal to the half wavelength of the standing wave in resonance with the IRaser cavity dimensions.Before collapse,the IRasers are filled with 5-10eV of IR radiation from the Plank energy in the ambient surroundings.During collapse,the IUR radiation is trapped within the IRaser by the high IR reflectivity of the bubble wall water molecules.As the IRaser cavity dimension dercreases,the cavity resonant frequency increases.The bubble wall molecules undergo a continuous population inversion by always being pumped to higher energy states that favor stimulated emission instead of absorption.IRaser resonant intensification produces 5-10MeV,i.e.,-10^6UV photons with 5-10eV.On average,SL induced cold fuison does not occur although a few X-ray photons are produced.If the IR thermal energy before collapse is enhanced to a total energy of 10keV.say by exciting the vibration modes of the water molecules at 2.73um with a HF laser,collapse produces an average X-ray energy of about 10keV.unlike hot fusion ,Sl induced cold fusion is not impossible. 相似文献
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Chen Xue Shi Ahmad I Andreyev A N Batchelder J C Bijnens N Bingham C R Blumenthal D Busse B C Conticchico L F Davids C N Huyse M Janssens R V F Mantica P Penttila 《核技术(英文版)》1998,9(1):11-13
FormationanddecayofneutrondeficientnucleiPoandPbChenXueShi1,2,AhmadI3,AndreyevAN4,BatchelderJC7,BijnensN4,BinghamCR2,5,Blum... 相似文献
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Tungsten-coated carbon and copper was prepared by vacuum plasma spraying (VPS) and inert gas plasma spraying (IPS), respectively. W/CFC (Tungsten/Carbon Fiber-Enhanced material) coating has a diffusion barrier that consists of W and Re multi-layers pre-deposited by physical vapor deposition on carbon fiber-enhanced materials, while W/Cu coating has a graded transition interface. Different grain growth processes of tungsten coatings under stable and transient heat loads were observed, their experimental results indicated that the recrystallizing temperature of VPS-W coating was about 1400℃ and a recrystallized columnar layer of about 30μm thickness was formed by cyclic heat loads of 4 ms pulse duration. Erosion and modifications of W/CFC and W/Cu coatings under high heat load, such as microstructure changes of interface,surface plastic deformations and cracks, were investigated, and the erosion mechanism (erosion products) of these two kinds of tungsten coatings under high heat flux was also studied. 相似文献
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T. WATARI Y. HAMADA A. NISHIZAWA T. NOTAKE N. TAKEUCHI 《等离子体科学和技术》2006,8(1):105-109
This paper reviews the theoretical foundations of zonal flow, putting emphasis on the linear response function of plasma to the external flow drive. An extension of the theory is made in order to apply it to helical systems and to study the properties of the zonal flow in the low frequency range. Further refinement of the theory is made incorporating the orbital effects of particles more precisely, and the role of neoclassical polarization current is identified. 相似文献
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WuGang HeZhen-Li 《核技术(英文版)》1998,9(3):176-180
The influence of fertilization with urea and ryegrass on nitrogen utilization and transformation in red soil has been studied by using ^15N tracer method.When urea and ryegrass were applied alone or in combination,the percentage of N uptaken by ryegrass from labelled urea was 3 and 1.7 times that from labelled ryegrass for the application rate of 200mgN.kg^-1 and 100mgN.kg^-1,respectively;combining application of ryegrass and ureareduced uptake of urea N and increased uptake of ryegrass N by ryegrass plant,but the percentage of N residued in soil increased for urea and decreased for ryegrass.when urea and ryegrass were applied alone,the percentage of N residued in soil from labelled ryegrass was more than 69% while that from labelled urea was less than 25%,and much more ryegrass N was incorporated into humus than urea N. 相似文献
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MA Yong-zhe WANG Hua-rong XU Xian ZHANG Pei-sheng 《中国原子能科学研究院年报》2006,(1):151-152
This paper introduces design and manufacture of fuel assembly for UO2 pellets irradiation program. The advanced UO2 pellet is large grained and is sintered with addictives of Al2O3/SiO2/Cr2O3. It will decrease the release rate of fission gas, reduce the PCI and inner pressure of the fuel rods, in result it will increase discharge bumup and extend loading period of fuel rod. The performance of large grain pellet must be proved through in-pile test. 相似文献
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《中国原子能科学研究院年报(英文版)》2006,(1)
This paper introduces design and manufacture of fuel assembly for UO2 pellets irradiation program. The advanced UO2 pellet is large grained and is sintered with addictives of Al2O3/SiO2/Cr2O3. It will decrease the release rate of fission gas, reduce the PCI and inner pressure of the fuel rods, in result it will 相似文献
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Temperature dependence and anisotropy of self- and mono-vacancy diffusion is important for modeling irradiation-induced microstructure evolution and the concomitant macroscopic deformation in Zr and its alloys. For self-interstitials, direct MD simulation of the diffusion has yielded useful data. Vacancy and self-diffusion, however, proceeds at a much slower rate, so that a direct simulation is not always practicable, particularly in the reactor-operating temperature regime. In this paper, we follow an alternate route based on thermodynamic integration and calculate the enthalpy, entropy and attempt jump frequencies of vacancy migration and formation in α-Zr for various temperatures ranging from 100 K to 1100 K. Their jump-direction and temperature dependencies are examined. The diffusivities so derived compare very well with other calculated results. Comparison with experimental self-diffusion data shows good general agreement except in the temperature regime near the α–β transformation. In this regime, the curvature in the Arrhenius plot of the self-diffusivity obtained is substantially smaller than the corresponding experimental results. Possible reasons are discussed. 相似文献