地质环境中微量元素与人类心血管疾病

介绍了地质环境中三种微量元素硒，铜，钼的分布特点及与人类心血管疾病的关系。     

Analysis of the heterogeneous multiscale method for parabolic homogenization problems

The heterogeneous multiscale method (HMM) is applied to various parabolic problems with multiscale coefficients. These problems can be either linear or nonlinear. Optimal estimates are proved for the error between the HMM solution and the homogenized solution.

     

HL-2M 装置真空室设计

HL-2M 真空室结构为“D”形截面的双层-薄壁-全焊接式-环状结构,内环直径 2m,外环径 5.22m, 高 3.02m,由 20 个扇形段组成而成。真空室上开设有 121 个窗口以满足真空抽气、实验诊断、辅助加热及工程安 装等方面的要求;支撑采用滑动杆式结构;材料选用 Inconel625、Inconel718 与 316L 组合。运用有限元法对真空 室进行了结构强度评估,真空室满足设计要求。     

Effects of an anisotropic parabolic potential and Coulomb’s impurity potential on the energy characteristics of asymmetrical semi-exponential CsI quantum wells

Because of its unique optoelectronic properties,people have studied the characteristics of polarons in various quantum well(QW)models.Among them,the asymmetrical semiexponential QW(ASEQW)is a new model for studying the structure of QWs in recent years.It is of great significance to study the influences of the impurity and anisotropic parabolic confinement potential(APCP)on the crystal’s properties,because some of the impurities,usually regarded as Coulomb’s impurity potential(CIP),will exist in the crystal more or less,and the APCP has flexible adjustment parameters.However,the energy characteristics of the ASEQW under the combined actions of impurities and APCP have not been studied,which is the motivation of this paper.Using the linear combination operation and Lee-Low-Pines unitary transformation methods,we investigate the vibrational frequency and the ground state energy of the strong coupling polaron in an ASEQW with the influences of the CIP at the origin of coordinates and APCP,and make a comparison between our results and previous literature’s.Our numerical results about the energy properties in the ASEQW influenced by the CIP and APCP may have important significances for experimental design and device preparation.     

Pulsatile flows in a lateral aneurysm anchored on a stented and curved parent vessel

We present particle tracking velocimetry measurements and flow visualization of pulsatile flow fields in a stented cerebrovascular lateral aneurysm model with a wide ostium anchored on a curved parent vessel. Among the stent parameters, the blocking ratioC _α ranging from 0% to 75% was selected to study its effect on the changes of intra-aneurysmal hemodynamics for the reference of minimally invasive endovascular aneurysm treatment. The Womersley number was 3.9 and the mean, peak, and minimal Reynolds numbers based on the bulk average velocity and diameter of the parent vessel were 600, 850, and 300, respectively. The results are characterized in terms of velocity vector field, coded streak images, region averaged velocity, vorticity, and wall shear stress. A critical range ofC _α related to the inflow location as well as the shape and number of intra-aneurysmal vortices is identified. The intra-aneurysmal flow activity, vortex strength, and wall shear stress are found to decrease with increasingC _α. Among theC _α examined,C _α=75% is the most favorable in attenuating the risk of aneurysmal rupture and promoting intra-aneurysmal thrombus.     

剪切散斑干涉与有限元优化计算相结合实现缺陷参数的定量求解

本文将剪切散斑干涉与有限元优化分析相结合，对薄壁压力容器缝缺陷进行了定量检测，通过对优化计算结果和已知的缺陷参数所构成的目标函数的求解，获得了较为精确的缺陷参数识别结果。     

用于抛物柱面空间功率合成天线的功分喇叭阵列

 提出了一种用于偏馈抛物柱面反射天线的功分喇叭。由于改善了口面上的电磁分布,该功分喇叭可以让馈源阵列的栅瓣电平抑制到－28 dB。用FEKO进行仿真发现,与传统用角锥喇叭阵列作为馈源的抛物柱面反射天线相比,使用功分喇叭直线阵列可以使空间功率合成天线的效率从68%提高到80%,同时天线的增益也能增加0.7 dB。     

汇聚式反射抛物面的宏观聚光测试

 目前反射式抛物面的检测主要是利用光的干涉法测量抛物面的光程来实现,虽然精度比较高,但却只能检测抛物面的光滑程度,而对抛物面的聚光效果无能力。该文从基本原理出发,重申反射式抛物面的聚焦成像本质,进而指出确定其聚光精度的关键是反射面各点的面积元方向与入射光的夹角关系,而不是光程关系。同时给出了应用特大口径平行光源或特大口径平行光源组合直接对反射抛物面进行检测的方法,它可以定性地检测出抛物面宏观的聚光效果和成像质量。     

X‐ray collimation by crystals with precise parabolic holes based on diffractive–refractive optics

Two crystals with precise parabolic holes were used to demonstrate sagittal beam collimation by means of a diffractive–refractive double‐crystal monochromator. A new approach is introduced and beam collimation is demonstrated. Two Si(333) crystals with an asymmetry angle of α = 15° were prepared and arranged in a dispersive position (+,?,?,+). Based on theoretical calculations, this double‐crystal set‐up should provide tunable beam collimation within an energy range of 6.3–18.8 keV (Θ_B = 71–18.4°). An experiment study was performed on BM05 at ESRF. Using 8.97 keV energy, the beam profile at various distances was measured. The experimental results are in good agreement with theoretical predictions. Owing to insufficient harmonic suppression, the collimated (333) beam was overlapped by horizontally diverging (444) and (555) beams.     

Models of thermodiffusion in 1D

The goal of the paper is to study the Cauchy problem for 1D models of thermodiffusion. We explain qualitative properties of solutions. In particular, we show which part of the model has a dominant influence on well‐posedness, propagation of singularities, L^p ? L^q decay estimates on the conjugate line, and on the diffusion phenomenon. Copyright © 2013 John Wiley & Sons, Ltd.