共查询到20条相似文献,搜索用时 15 毫秒
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作为一种有竞争力的能源系统,Z箍缩聚变裂变混合堆(Z-FFR)正在开展概念研究,包层研究正是其中重要的一部分。建立了Z-FFR包层设计模型,分析了包层影响因素、中子平衡、通量与功率密度、燃耗等方面,表明该包层设计在50年内能量放大因子、氚增殖比和燃料增殖比的平均值分别为14.91, 1.294和5.140,满足设计要求。针对聚变源的脉冲特性进行了包层的瞬态中子学分析,发现燃料区中子脉冲可分为聚变中子、瞬发裂变中子和缓发裂变中子脉冲三个部分,绝大部分热量约在0.01 s内沉积。结果较完整地给出了Z-FFR包层的中子学参数,为概念研究提供了基础。 相似文献
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作为一种有竞争力的能源系统,Z箍缩聚变裂变混合堆(Z-FFR)正在开展概念研究,包层研究正是其中重要的一部分。建立了Z-FFR包层设计模型,分析了包层影响因素、中子平衡、通量与功率密度、燃耗等方面,表明该包层设计在50年内能量放大因子、氚增殖比和燃料增殖比的平均值分别为14.91,1.294和5.140,满足设计要求。针对聚变源的脉冲特性进行了包层的瞬态中子学分析,发现燃料区中子脉冲可分为聚变中子、瞬发裂变中子和缓发裂变中子脉冲三个部分,绝大部分热量约在0.01s内沉积。结果较完整地给出了Z-FFR包层的中子学参数,为概念研究提供了基础。 相似文献
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Jian-Sheng Wang 《Journal of statistical physics》1996,82(5-6):1409-1427
The standard two-dimensional uniformly driven diffusive model is simulated extensively for much larger systems with a multi-spin coding technique. The nonequilibrium phase transition is analyzed with anisotropic finite-size scaling both at the critical point and off the critical point. The field-theoretic values of critical exponents fit the data well at and aboveT
c
. BelowT
c
the scaling is rather difficult and the results are not conclusive. 相似文献
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基于脉冲功率技术的Z箍缩过程可以实现驱动器电储能到X光辐射的高效率转换,形成极端温度、密度、压力条件,近年来在惯性约束聚变及高能量密度应用中取得了一系列重要进展。综述了国际上辐射间接驱动和磁直接驱动两条Z箍缩聚变技术路线发展现状,简要介绍了我国Z箍缩聚变尤其是7~8 MA脉冲功率装置上的动态黑腔研究进展;分别从辐射与物质相互作用、辐射不透明度、材料动态特性、实验室天体物理等方面,概述了Z箍缩应用于高能量密度物理研究的技术路线和主要成果。希望通过对Z箍缩聚变及高能量密度应用研究的论述和发展趋势分析,推动我国Z箍缩研究领域的进一步发展。 相似文献
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从原子的电离能和维持等离子体所需能量出发,给出了估算任一元素材料,要产生任一壳层的X射线辐射,每个离子(原子)所需要的基本能量和要达到的内爆箍缩速度的方法.对“强光一号”加速器上典型的氪喷气和部分钨丝阵Z箍缩实验的电流和电压波形所蕴涵的丰富物理信息进行了分析,得到了电感和洛伦兹(Lorentz)力做功等物理量的变化规律以及负载参数变化对它们的影响.该电感与基于壳层模型计算出的电感有较大的差异.前者随箍缩开始而缓慢增大,甚至在箍缩到心和飞散后还在增大,最后大致稳定在100 nH附近.差异可能是由于壳层模型过于简化和电流电压的测点同负载有一定的距离而造成的.当丝阵直径为8 mm时,洛伦兹力做功最大;当丝阵直径相同时,丝数较大时,洛伦兹力做功也较大.同时还对该加速器的喷气和丝阵负载的线质量进行了优化,表明也是直径为8 mm的钨丝阵为最佳负载,这同实验的优化结果也一致. 相似文献
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A system for the automatic acquisition and analysis of gamma-ray spectra that is used in the studies of photonuclear reactions with the activation technique in described. The system is comprised of a database, which is used to access data over a network, and of a spectrum analysis program. Experimental procedures and data analysis are greatly simplified with the use of the described system. 相似文献
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Ahmed Z Akerib DS Arrenberg S Bailey CN Balakishiyeva D Baudis L Bauer DA Brink PL Bruch T Bunker R Cabrera B Caldwell DO Cooley J do Couto e Silva E Cushman P Daal M DeJongh F Di Stefano P Dragowsky MR Duong L Fallows S Figueroa-Feliciano E Filippini J Fox J Fritts M Golwala SR Hall J Hennings-Yeomans R Hertel SA Holmgren D Hsu L Huber ME Kamaev O Kiveni M Kos M Leman SW Liu S Mahapatra R Mandic V McCarthy KA Mirabolfathi N Moore D Nelson H Ogburn RW Phipps A Pyle M Qiu X Ramberg E Rau W 《Physical review letters》2011,106(13):131302
We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ~10 GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments. 相似文献
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R. T. Herrod 《Zeitschrift fur Physik C Particles and Fields》1982,13(4):313-319
Results from a numerical evolution of the Altarelli-Parisi equations are presented, covering the full range 0<x<1. The predictions of leading order and next-to-leading order in perturbative QCD, are compared with the most precise currently available data. All necessary assumptions are quantitatively discussed. 相似文献
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This paper investigates statistical properties of high-frequency intraday stock returns across various frequencies. Both time series and panel data are utilized to explore the properties of probability distribution, dynamic conditional correlations, and scaling analysis in Dow Jones Industrial Average (DJIA) and Nasdaq intraday returns across 10-min, 30-min, 60-min, 120-min, and 390-min frequencies. The evidence shows that both returns and volatility (standard deviation) increase with the increasing scaling from 10-min to 390-min intervals. By fitting an AR(1)-GARCH(1,1) model to intraday data, we find that AR(1) coefficients are negative for DJIA returns and positive for Nasdaq, exhibiting a positive and negative feedback strategy in DJIA and Nasdaq, respectively. The evidence also shows that these coefficients are statistically significant for either including or excluding opening returns for the 10-min and 30-min frequencies. By examining the dynamic conditional correlation between the DJIA and the Nasdaq across different frequencies, a positive correlation ranging from 0.6 to 0.8 was found. In addition, the variance of the dynamic correlation coefficients is decreasing and appears to be stable for the 2001-2003 period. Finally, both returns on DJIA and Nasdaq satisfy the stable Lévy distributions, implying that both markets can converge to equilibrium by self-governing mechanism after shocks. Results of this work provide relevant implications for investors and policy makers. 相似文献
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A. Maksimchuk S. Reed N. Naumova V. Chvykov B. Hou G. Kalintchenko T. Matsuoka J. Nees P. Rousseau G. Mourou V. Yanovsky 《Applied physics. B, Lasers and optics》2007,89(2-3):201-207
By focusing 40-TW, 30-fs laser pulses to the peak intensity of 1019 W/cm2 onto a supersonic He gas jet, we generate quasi-monoenergetic electron beams for plasma density in the specific range 1.5×1019 cm-3≤ne≤3.5×1019 cm-3. We show that the energy, charge, divergence and pointing stability of the beam can be controlled by changing ne, and that higher electron energies and more stable beams are produced for lower densities. The observed variations are explained
physically by the interplay among pump depletion and dephasing between accelerated electrons and plasma wave. Two-dimensional
particle-in-cell simulations support the explanation by showing the evolution of the laser pulse in plasma and the specifics
of electron injection and acceleration. An optimized quasi-monoenergetic beam of over 300 MeV and 10 mrad angular divergence
is demonstrated at a plasma density of ne≃1.5×1019 cm-3.
PACS 52.35.-g; 52.38.Hb; 52.38.Kd; 52.65.-y 相似文献
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I. Zvára 《Physics of Atomic Nuclei》2003,66(6):1125-1130
Studies of chemistry of the transactinoid elements, which are available only as single atoms, by gas (thermo)chromatographic techniques can provide the adsorption enthalpies of the atoms or molecules. These values serve the ultimate goal—to characterize bulk volatility of the species in terms like sublimation enthalpies. The paper attempts an in-depth discussion of the statistical significance of the adsorption enthalpies derived in such experiments. Usually, the counting statistics are very poor and one faces nonstandard problems in evaluating the confidence intervals for the values of parameters. Here, a most efficient way seems to be the Bayesian approach, realized, when necessary, by Monte Carlo simulations of the counting results. Necessarily, the adsorption enthalpy is not evaluated based on the second law of thermodynamics but through accepting an a priori value of the adsorption entropy. More additional assumptions about the mechanisms and parameters involved are needed. This may produce systematic errors in the quantitative conclusions; the analysis of some recent works with elements 106 and 108 corroborates this concern. Despite such problems, it is possible to reveal qualitative differences in the adsorption behavior of a transactinoid and its expected known congeners as well as to use chemistry for an independent assignment of the atomic numbers of transactinoid nuclides. 相似文献
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K. Vokurka 《Czechoslovak Journal of Physics》1988,38(1):35-46
Experimental data on spark and laser generated bubbles published in the literature are evaluated and compared with a theoretical model. It is found that within the first bubble oscillation the theory agrees rather well with the experiments. However, for later oscillations unaccounted energy losses occur in real bubbles. These losses seem to be of the same origin as the losses discussed in connection with explosion generated bubbles. 相似文献
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We propose an experiment to obtain the phase diagram of the fermionic Hubbard model, for any dimensionality, using cold atoms in optical lattices. It is based on measuring the total energy for a sequence of trap profiles. It combines finite-size scaling with an additional "finite-curvature scaling" necessary to reach the homogeneous limit. We illustrate its viability in the 1D case, simulating experimental data in the Bethe-ansatz local-density approximation. Including experimental errors, the filling corresponding to the Mott transition can be determined with better than 3% accuracy. 相似文献
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Improved data analysis method of single-molecule experiments based on probability optimization 下载免费PDF全文
To extract the dynamic parameters from single molecule manipulation experiments, usually lots of data at different forces need to be recorded. But the measuring time of a single molecule is limited due to breakage of the tether or degradation of the molecule. Here we propose a data analysis method based on probability maximization of the recorded time trace to extract the dynamic parameters from a single measurement. The feasibility of this method was verified by dealing with the simulation data of a two-state system. We also applied this method to estimate the parameters of DNA hairpin folding and unfolding dynamics measured by a magnetic tweezers experiment. 相似文献