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双语推荐：轨道参数变化发现

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研究一个周期受击陀螺的保真度、隧道效应和能量量子期待值.研究发现,随着打击强度λ的增加,经典相空间结构从规则的轨道到出现岛再到完全混沌.当参数取为α=π/2,λ=3.0时,以相空间的稳定固定点处的周期轨道对应的相干态作为初始态的保真度最高,而且随时间呈周期性变化;以规则区域对应的相干态作为初始态的保真度呈不规则的变化;以混沌区域对应的相干态作为初始态的保真度有很大幅度的下降.当参数取为α=1.0,λ=2.0时,相空间中两个岛中心对应的相干态可以相互遂穿,隧穿周期随混沌的渗透大幅度缩短.经典相空间中规则区域和混沌区域的相干态对应的能量量子期待值随时间的变化表现出准周期性,但是有不同的表现形式.
This paper studies fidelity,tunneling,and the quantum expectation value of energy for a periodically kicked free top. The study found that,with the strengthλincreased the classical phase space portraits transform from the regular track to island and finally complete chaotic. When α=π/2,λ=3. 0,fidelity that the initial coherent state corresponds to the fixed point is the highest and presents regular periodic change. Fidelity that the initial coherent state corresponds to regular track presents irregular change. Fidelity that the initial coherent state corresponds to chaos reduces drastically. When α=1. 0,λ=2. 0,two coherent states that correspond to the centre of two islands can mutually tunnel each other, the period of tunneling will be greatly reduced when chaos set in. Quantum expectation values of energy for regular and chaotic region are quasi-periodic,but the manifestations are different.

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采用第一性原理的方法针对PtZr合金，计算了在0～80GPa高压环境下的晶格常数、弹性常数、体模量、剪切模量和电子结构。计算结果发现，PtZr合金的晶格参数，晶胞体积随着压力的增加而线性降低。分析其弹性模量，在高压环境下，PtZr合金的体模量随着压力的增加而线性增大，但剪切模量在0～40GPa范围内随着压力的增加而增大，当达到40GPa时出现一个极大值，当压力继续增大时，剪切模量基本趋于稳定。这种弹性模量的变化主要是因为在高压条件下，Pt的5d电子轨道上的电子和Zr的4d电子轨道的电子相互作用增强，形成较强的金属键所致。
The lattice parameters, volume, elastic constants, bulk modulus, shear modulus and electronic structure of PtZr intermetallics under high pressure were studied by first-principle approach. With increase of the pressure, the lattice parameters and volume of PtZr were linearly decreased. By the calculation of elastic modulus it was indicated that the bulk modulus was increased with the pressure increase. However, the shear modulus reached the biggest values at the pressure of 40 GPa and tended to stable with continuously increase of pressure. The variation of shear strength is derived from the strongly hybridization between Pt(5d) states and Zr(4d) state forming the Pt(d)-Zr(d) metallic bonds.

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采用第一性原理的计算方法,研究了全部由轻元素构成的半Heusler型NaAlGe合金中,掺杂元素对合金拓扑能带结构的影响.发现利用同族的Cs元素掺杂替换Na元素,能够诱导Na1-x Csx AlGe合金的能带结构由原本正常带序(0 x0.125)转换为反转带序(0.125 x 1).基于对这一现象的深入讨论,我们提出在几乎没有自旋-轨道耦合作用的材料中,掺杂元素(Cs)是通过其离子半径的不同,进而影响晶格参数变化导致另外两种近邻原子间杂化作用发生变化,来诱导拓扑反带结构形成的.
The influences of doping whit congeners on the band topology in half Heusler-type of NaAlGe alloys are investigated using the first-principles calculations. It is found that the Na1-xCsxAlGe alloys with a normal band order are converted into topological nontrivial phases when x is up to 0.125. We argue that it is the degree of hybridization between Al and Ge determine the band order at the Fermi level. The Na or Cs only plays a role of the valence electron contributor and influences the lattice parameter.

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随着高速铁路建设的兴起，轨道以及沿线附近建筑物承受低幅值小应变振动荷载的作用。对于小应变振动下土体的有限元计算，如何确定连接应力和应变之间纽带的刚度张量E，对于建立合理的预测模型来分析高速铁路轨道以及沿线建筑物的沉降变形至关重要。低幅值小应变振动下剪切模量G和阻尼比D随剪应变幅值的变化是反映土体刚度及阻尼特征最重要的两个参数。通过共振柱试验发现，振动荷载作用下土体的剪切模量 G 必须通过振动应变幅值和固结围压共同来确定，即使在小应变（剪应变幅值10-6参数过多，关键参数γ0的取值没有明确的物理方法。对于低幅值小应变振动情形，为了简便起见，忽略大应变振动情形下由于循环效应和速率效应引起的强度变化，在Mohr-Coulomb破坏准则的基础上，通过引入由给定应力状态下的静抗剪强度τf与最大剪切模量Gmax的比值来确定的参考剪应变gref来代替Davidenkov模型中的拟合参数g0，尝试提出简化的两参数Davidenkov模型，并通过共（自）振柱试验验证了该方法对计算低幅值小应变振动情形下剪切模量和阻尼比的可行性。
Railway track and nearby structures in the vicinity of high-speed railway are exposed to low-amplitude small-strain vibrations as high-speed railway traffic construction activities arise. In the finite element (FE) method, how to determine the stiffness tensor E is important to build a rational predicting model to analyze the settlement of track and nearby structures in the vicinity of high-speed railway. Shear modulus G and damping ratio D which will vary with shear strain amplitude are two important stiffness and damping parameters. It is found through resonant column test study that the shear modulus G of soil due to vibrations must be determined by the strain amplitude and the confining pressure, even though under small-strain (shear strain amplitude 10-6

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针对Xenics公司的一款InGaAs探测器,根据载荷工作环境要求,轨道高度700km,在轨工作3年的总剂量辐射为2 krad( Si),技术指标要求探测器的抗总剂量辐射能力要在10 krad( Si)以上。因此对其进行总剂量为30 krad( Si)的60Co-γ辐射试验[1-2]。对比辐照前后探测器的参数变化,发现随着总剂量的增加,探测器的暗电流有所增大,响应度有所降低,整体性能略有下降,但满足指标要求。分析γ辐射对探测器影响的内在机理,为后续InGaAs探测器抗总剂量辐射加固提供依据和参考。
According to environmental requirement of payload,the total dose irradiation is 2 krad( Si) when the orbit-al altitude is 700km and work period is 3 years. So the InGaAS detector of the Xenics company should have the a-bility of 10 krad( Si) resistant radiation. In order to study the characteristics of this InGaAs detector,irradiation test was conducted using a Cobalt60-γ with the total dose of 30 krad( Si) . Main parameters of the detector was studied before and after irradiation. After irradiation,the dark current increases and response of detector decreases with the irradiation dose increasement,which indicates that performance of the detector becomes worse with increasing irradi-ation dose. It is analyzed that the damage mechanisms of detector afterγirradiation,there results provide reference for the total dose resistant irradiation hardening in future.

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