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1.
Design and analysis of the tunnel connecting the beamcorridor and the spectrum hall of the CSNS
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There is a tunnel connecting the beamcorridor and the target station in the spectrum hall in the CSNS project.The length of the tunnel is about 20 m.The shielding design of the tunnel is very significant for the persons working in the spectrum hall because the tunnel is not covered ed soil for shielding.In order to reduce the dose rate at the exit of the cable ducts,we use the ISIS construction,which is designed with four turnings,as a reference for the tunnel design.The thickness of the shielding is obtained by a simulationwith the Monte Carlo Code FLUKA.The result is compared with the data obtained with Moyer Mode and the reliability of the simulation is proved.This paper provides the basis for the design of the tunnel. 相似文献
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By reexamining the analysis of Basu and Biswas, based on the stereographic projection method of Fock and Levy, it is shown
that the general solution of the Wick-Cutkosky model in the instantaneous approximation, hitherto unreported, involves only
one quantum number; this is contrasted with the well-known solution which involves two quantum numbers, but for which the
spectrum is degenerate with respect to one of them. The latter situation is shown to hold under a rather special circumstance. 相似文献
3.
Ramon Lapiedra Juan Antonio Morales-Lladosa 《General Relativity and Gravitation》2013,45(6):1145-1161
The case of asymptotic Minkowskian space-times is considered. A special class of asymptotic rectilinear coordinates at the spatial infinity, related to a specific system of free falling observers, is chosen. This choice is applied in particular to the Schwarzschild metric, obtaining a vanishing energy for this space-time. This result is compared with the result of some known theorems on the uniqueness of the energy of any asymptotic Minkowskian space, showing that there is no contradiction between both results, the differences becoming from the use of coordinates with different operational meanings. The suitability of Gauss coordinates when defining an intrinsic energy is considered and it is finally concluded that a Schwarzschild metric is a particular case of space-times with vanishing intrinsic 4-momenta. 相似文献
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James M. Kingsley 《Foundations of Physics》1975,5(2):295-300
The special theory of relativity is based on two postulates: (I) All inertial frames are equivalent for the performance of physical experiments; and (II) the velocity of light is a universal constant. It is shown that if postulate I is true, then postulate II is not true, and if postulate II is true, then postulate I is not true. Further, it is shown that the only possible velocity consistent with postulate I follows the rule that the velocity of light with respect to the observer is equal to the velocity of light with respect to the source plus the velocity of the source with respect to the observer. 相似文献
6.
A method of calculation is presented for the yield of an electron excitation process by a channelled particle in a single encounter with an atomic row or plane in a crystal. It is shown that, if ψ is the initial angle between the ion trajectory and the row or plane, the number of inner-shell electrons excited is an increasing function of ψ whereas the number of outer electrons excited may decrease with increasing ψ. 相似文献
7.
The evolution of the dielectric spectrum of triglycine sulfate with time is investigated in the frequency range from 20 MHz to 1 Hz at a temperature of 48.8°C for 420 min. It is revealed that the evolution of the dielectric spectrum exhibits a non-steady-state behavior due to the broadening of the relaxation-time spectrum. The process clearly manifests itself in a transformation of the Cole-Cole diagram with time. The transformation to a quasi-stationary state is completed in approximately 1 h. The phenomenon is explained by the retarded motion of domain walls. The inference is made that, for ferroelectrics, the time evolution of all parameters associated with the domain-wall state should be a universal property. 相似文献
8.
基于势流假设,建立气泡与壁面耦合数值模型,运用边界积分法求解,并开发三维计算程序,计算值与实验值符合很好.从气泡与壁面相互作用的基本现象入手,基于开发的程序系统地研究了刚性壁面附近气泡的动力学特性,其中包括水平壁面及倾斜壁面,研究壁面的Bjerknes效应与各特征参数之间的关系,并将各种工况的计算结果与基于Kelvin-impulse理论的Blake准则进行对比分析讨论,得出偏射流方向及壁面压力与气泡的特征参数有密切的关系,同时给出了Blake准则的适用范围.旨在为相关的近壁面气泡动态特性研究提供参考.
关键词:
气泡
壁面
边界积分
Bjerknes效应 相似文献
9.
In the ocean without fluctuations, the sound field is calculated by the method of geometrical acoustics with allowance for purely water-path rays in a sound channel of canonical shape with a thickness of 4 km for distances of 500 and 2000 km. The sound field is determined as a sum of individual rays arriving at a given point with their own amplitudes and phases. It is shown that the vertical structure of the sound field consists of a number of caustics separated by regions with a quasi-random distribution of the field whose amplitude is much smaller than that in the caustics. At a fixed distance, the number of caustics is equal to the difference between the numbers of the ray turning points at the boundaries of the departure angle range. As the distance from the source increases, the number of caustics increases proportionally to distance. 相似文献
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求解定态薛定谔方程常常会涉及到常微分方程的本征值问题.目前解常微分方程本征值用的比较多的方法是以龙格-库塔方法为基础的打靶方法.打靶方法常用,但是计算时间长.当边界条件比较复杂或比较敏感的时候,用松弛法会有更好的效果.本文用松弛法解薛定谔方程,并和理论解进行比较.发现松弛法得到的数值解和理论解符合度很高,而且使用松弛法... 相似文献
13.
在色噪声间的关联程度受时间周期调制的激光系统中,研究噪声受信号调制情况下的随机共振.用线性化近似的方法计算了光强关联函数及信噪比.具体讨论信噪比随噪声强度、噪声自关联时间、信号频率以及时间周期调制频率的变化关系.发现一种新的随机共振:信噪比随时间周期调制频率的变化出现周期振荡型随机共振;发现广义随机共振:信噪比随抽运噪声自关联时间的变化、随信号频率的变化出现随机共振;同时也存在典型的信噪比随噪声强度的变化而出现的随机共振.而信噪比随量子噪声自关联时间的变化表现为抑制.
关键词:
信号调制
时间周期调制
噪声间关联程度
周期振荡型随机共振 相似文献
14.
We propose one a variant of calculation of the energy spectrum of bound state systems with relativistic corrections. In the
framework of quantum field theory, an expression that takes into account relativistic corrections to the mass of the bound
state with a known nonrelativistic pair interaction potential is proposed on the basis of calculating the asymptotic behavior
of correlation functions of the corresponding field currents with the necessary quantum numbers. Excluding the time variables
allows one to determine nonperturbative corrections to the interaction potential. The following results have been obtained
in the framework of this approach. The nonperturbative corrections arising due to the relativistic nature of a system to the
interaction Hamiltonian are determined. The dependence of the constituent mass of bound-state forming particles on the free
state mass and on the orbital and radial quantum numbers is analytically derived. The energy level shift of muonic hydrogen
taking into account relativistic corrections is calculated. The energy spectrum of a wide class of potentials that describe
the Coulomb bound state is analytically derived with relativistic corrections. The mass spectrum of the glueballs and the
constituent masses of the gluons are analytically calculated taking into account spin-orbit, spin—spin, and tensor interactions.
Our numerical results have shown very good agreement with the lattice data. Taking into account nonperturbative and nonlocality
characters of interactions, the mass spectrum of the mesons consisting of light-light and light-heavy quarks with orbital
and radial excitations is determined. Our results show that good agreement with the experimental data for the slope and the
intercept of the Regge trajectory can be obtained only taking into account the nonperturbative and the nonlocal characters
of interactions. The dependences of the constituent masses of constituent particles on the masses of a free state are certain.
When quarks are light, then the difference between current and valent masses of quarks is greater than valent masses of quarks,
and when quarks are heavy, then the difference between these masses is insignificant. One of the alternative variants of taking
nonlocality into account has been suggested for the definition of properties of hadrons at large distances. The dependence
of the constituent masses of constituent particles on the radius of confinement is determined. 相似文献
15.
计算了基于拟氨基酸编码方法下的同义密码子的相对使用度,分析了78个人类基因(19967个密码子)中基于拟氨基酸编码方法下的同义密码子的偏好使用情况.石秀凡等的研究结果显示了人类基因中基于基因组基因编码方法下,对同义密码子的选择在所有密码子家族中仍都呈现明显一致的偏好.即偏好使用密码子-反密码子结合作用强的密码子,恰好是以 c结尾的密码子;且避免使用结合作用中度的密码子.依据结果和数据分析, 推测人类基因对密码子的选择除了受基因组结构中 isochore和基因签名的影响外,还和密码子-反密码子结合强度密切相
关键词:
拟氨基酸编码方法
同义密码子
偏好
人类基因 相似文献
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考虑弹丸在钢筋交汇处与钢筋直接发生作用的情况,提出了弹丸侵彻钢筋混凝土的近似模型。利用该模型得到了弹丸侵彻钢筋混凝土过程中弹丸的加速度时间历程。计算结果与实验结果符合较好。用该模型分析了不同配筋结构、配筋尺寸和网眼尺寸对侵彻深度和侵彻过程的影响,结果表明:弹丸从钢筋交汇处侵彻时,当弹丸动能相对较小时,随着网眼尺寸的减小,弹丸的大部分能量均消耗在侵彻第一层配筋结构中,当弹丸动能较大时,不管网眼尺寸多大,第一层配筋均只消耗掉弹丸的部分能量;配筋直径和网眼尺寸对侵彻深度的影响较大。 相似文献
18.
We present a detailed study of the solutions of the hypernetted chain integral equation inside the gas-liquid coexistence region for simple Lennard-Jones fluids. The study is performed by means of a hybrid Newton-Raphson algorithm extended to cope with complex solutions. In this way, we have unequivocally confirmed that the origin of the well-known HNC singular behavior inside the coexistence curve is linked to the onset of complex solutions. As density is increased starting from the vapor phase along isotherms inside the coexistence region, another singularity is encountered (very likely linked with the existence of a complex multiple solution point), and correlations start to diverge. Therefore, with the numerical approach here presented it is not feasible to join the liquid and vapor phases through an analytically continuous path of real and complex solutions. Finally, a study of the transition from the mean spherical approximation behavior (characterized by the presence of a spinodal divergence) to the peculiar hypernetted chain sort of singularity is also presented. 相似文献
19.
微型投影机光学引擎的研究 总被引:1,自引:0,他引:1
设计了一种针对个人用户使用的微型投影机光学引擎,系统为单片式数字光线处理器结构,采用红绿蓝三色大功率高亮度发光二极管作为光源,使用X棱镜作为合色元件,从而实现38.1~50.8 cm的彩色投影显示.对设计结果进行理论分析后可知,设计结果满足投影显示对颜色的要求,光学引擎的理论效率为16.1%.同时利用Light Tools仿真软件对系统进行建模分析,300万条光线追迹仿真的结果表明,光学引擎的效率为14.6%,与理论分析结果基本符合,屏幕上光通量为22.8 lm,其美国国家标准协会规定的九点照度均匀性达到91.55%和-93.36%,满足设计要求. 相似文献
20.
J. Šlechta 《Czechoslovak Journal of Physics》1968,18(10):1299-1308
On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given. 相似文献