用于太阳能光伏发电的高倍聚光系统

 研究了基于三结型（InGaP/InGaAs/Ge）高效太阳能电池的太阳能光伏发电的高倍聚光系统。该系统采用高次非球面光学玻璃卡塞格林系统,运用Zemax和Tracepro光学设计软件完成200~500倍太阳能聚光系统的设计,同时设计了单片型高倍太阳能聚能光学组件,用热压成型方法研制了太阳能聚能透镜（副镜）。采用16个性能相同的聚光光学组件和相同数量的三结型太阳能电池组成高倍聚光型太阳能光伏组件,极大地提高了聚光比,为太阳能光伏发电的高倍聚光器设计提供参考和依据。     

Crystallization kinetics, glass transition kinetics, and thermal stability of Se70−xGa30Inx (x=5, 10, 15, and 20) semiconducting glasses

Crystallization and glass transition kinetics of Se_70−xGa₃₀In_x (x=5, 10, 15, and 20) semiconducting chalcogenide glasses were studied under non-isothermal condition using a Differential Scanning Calorimeter (DSC). DSC thermograms of the samples were recorded at four different heating rates 5, 10, 15, and 20 K/min. The variation of the glass transition temperature (T_g) with the heating rate (β) was used to calculate the glass transition activation energy (E_t) using two different models. Meanwhile, the variation of the peak temperature of crystallization (T_p) with β was utilized to deduce the crystallization activation energy (E_c) using Kissinger, Augis-Bennet, and Takhor models. Results reveal that E_t decreases with increasing In content, while both T_g and E_c exhibit the opposite behavior, and the crystal growth occurs in one dimension. The variation of these thermal parameters with the average coordination number <Z> was also discussed, and the results were interpreted in terms of the type of bonding that In makes with Se. Assessment of thermal stability and glass forming ability (GFA) was carried out on the basis of some quantitative criteria and the results indicate that thermal stability is enhanced while the crystallization rate is reduced with the addition of In to Se-Ga glass.     

基于同步辐射加速器的康普顿背散射γ光源性质及其应用研究

本文介绍了利用康普顿背散射 (BCS)产生γ射线的原理 ,并以SSRF储存环电子运行参数为例 ,给出了利用BCS方法产生MeV量级γ射线束的计算结果 ,预期该光子束具有高强度、高极化度、单色性、方向性好等优点。同时对国际上已运行和拟建的高能和低能γ束线站的装置和性能作了简要介绍 ,并分别探讨了高能和低能准单色极化γ射线在核物理和核天体物理研究中广泛的应用前景。文中对基于正对以及离轴几何条件下 ,采用直线加速器加速的电子同短脉冲强激光发生Compton/Thomson散射的激光同步辐射源作了初步探讨 ,这一方法为我们构建超短脉冲的高亮度、准单色、可调谐的X γ射线源开辟了一条新途径。     

Dynamical chaos and stochastic mechanism of high-energy negatively charged particle deflection by bent crystals

Deflection of high-energy negatively charged particles in straight and bent crystals through multiple scattering by crystal atomic strings was considered for the case in which the initial angle between the particle momentum and one of the main crystallographic axes was approximately four critical angles of axial channeling. It was shown that in a bent crystal with a small crystal thickness, when the crystal bend was less than the beam incidence angle, the beam deflected in the direction opposite to the direction of the crystal bend. At larger crystal thicknesses, the large part of the beam starts to deflect in the direction of the crystal bend. In addition, there is a group of particles that follow the crystal axis bend in the angular region of approximately the critical angle of axial channeling with respect to the current direction of the crystal axis. It was shown that in all of these deflection processes, the periodicity of the location of atomic strings in the crystal does not influence the angular distributions of scattered particles. This fact is connected with the effect of dynamical chaos in particle motion in the periodical field of bent crystal atomic strings. It was also shown that observed in a recent CERN experiment effect of beam deflection, when the angle between the initial particle momentum and the crystal axis was approximately four critical angles of axial channeling, is due to peculiarities of the stochastic multiple scattering of particles by bent crystal atomic strings. These peculiarities are connected with the effect of dynamical chaos in particle motion in crystals.     

Numerical simulation of a Gaussian beam profile passing through a Kerr medium

The circular Gaussian beam shape has been simulated by numerical evaluation on beam shape based on z-scan method through beam radius. This method is useful in many studies such as z-scan experiments. The validity of the relation between peak and valley separation in close aperture data and the diffraction length of the beam has been investigated by this method for some real cases. The results are in good agreement with the experimental studies.     

Bifurcation Instability of sheet metal during spring-back

In automotive and home appliance industries, there are many complex-shaped sheet metal components which need to be fabricated in multiple stamping operations. For example, the manufacturing of an outer case of washing machine consists of stamping followed by a bending operation. After the first stage of the stamping process, a large amount of spring-back takes place, and therefore, it is difficult to proceed to the next stage of the bending process. In the stamping process of that kind of sheet component with low geometric constraint, the forming area is large compared to the forming depth. Therefore, the formed part is in an unstable state and is less geometrically constrained, which causes a large amount of spring-back. To investigate this phenomenon, finite element analyses are carried out. During a spring-back analysis after forming, bifurcation takes place and the finite element solution procedure using the Newton–Raphson scheme becomes unstable. To get a stable post-bifurcation solution, a bifurcation algorithm is introduced at the bifurcation point. The deformed shapes obtained from finite element analyses are in good agreement with the experimental data. From this study, it is shown that the bifurcation behaviour enlarges the spring-back and the degree of dimensional error. To obtain additional possible post-bifurcation solutions, non-bifurcation analyses using initial guesses obtained in a modal analysis are carried. For the initial guesses, lowed four eigenmodes are utilized. Finally, the post-bifurcation behaviour and spring-back amount are investigated for various process parameters including the forming depth, punch width and corner radius.     

Total internal reflection–refraction beam expander

Beam expanders being used presently have complex structure and none is perfect. A novel beam expander is proposed first. The beam expander can magnify (or decrease) the diameter of incident laser beam according to the theory of total internal reflection–refraction (TIR-R) principle. The characteristic of the beam expander was studied by using ray-tracing method and computer simulation. The beam expander can propagate a parallel laser beam along the propagation axis and would not change the propagation direction of the beam. For a nonparallel beam the Lagrange invariant (the product of diameter and divergence angle) is not constant. This beam expander would be an effective device in some applications.     

Slip-line modeling of machining with a rounded-edge tool—Part I: new model and theory

The effect of tool edge roundness attracts growing attention from the international machining research community due to ever accelerating applications of precision, super-precision, micro-, and nano-machining technologies in a wide variety of modern industries. A new slip-line model for machining with a rounded-edge tool and its associated hodograph are proposed in this paper. The model consists of 27 slip-line sub-regions, each sub-region having its own physical meaning. It is demonstrated that the model simultaneously takes into account nine effects, such as the shear-zone effect and the size effect, which commonly occur in machining. Eight groups of machining parameters, such as the ploughing (parasitic or non-cutting) force and the chip up-curl radius, can be simultaneously predicted from the model. Furthermore, the model incorporates eight slip-line models previously developed for machining during the last six decades as special cases. An additional special case that involves a parallel-sided shear zone can also be derived from the new model. A mathematical formulation of the model is established based on Dewhurst and Collins's (1973) matrix technique for numerically solving slip-line problems. A purely analytical equation is proposed to predict the thickness of the primary shear zone. This equation is also employed to predict the shear strain-rate in the primary shear zone.     

Biochip fluorescence detection system with spatial and spectral separation

A novel optical arrangement for fluorescence detection that employs spatial separation as well as spectral filter to increase the signal to noise ratio is proposed. Using a prism and two mirrors, the elliptical laser beam of a laser diode, as an excitation light, is homogenized and the transmitted excitation light is separated from the fluorescence not to reach the collecting optics. Uncooled CCD can capture the fluorescence image of up to 40 fluorescently-labeled protein patterns without scanning or mechanical translation. This paper presents the simulation, construction and measurement results of the developed optical system. The measurements show that the combination of prism and mirrors converts the excitation light from the laser diode to uniform illumination on the specimen, and provides the separation between excitation and fluorescence light to give high signal to noise ratio. It is also possible to assay various protein concentrations ranging from 1000 to 10 ng/ml reliably. We believe that the proposed fluorescence detection system can be used to build a commercially valuable, low cost, hand-held or miniature fast detection device for point-of-care applications.     

宾汉姆体的缓凝砂浆在单螺杆挤出机中的流动

在实验的基础上，研究了宾汉姆体的缓凝砂浆在单螺杆挤出机中的流动；运用流变学理论， 建立了缓凝砂浆螺旋输送物理模型；对缓凝砂浆螺旋输送与包裹机构的工作机理进行了分析 与研究，得出了缓凝砂浆连续输送的条件，螺杆转速必须大于临界转速. 实验发现：宾汉姆 体的缓凝砂浆在螺旋输送与包裹机构中当螺杆转速在78$\sim$240\,r/min范 围内可实现连续输送和包裹.