双级制冷压缩机配置的节能优化

通过对国产典型产品比较发现,双级螺杆式压缩机COP值高于双级活塞式压缩机。在-35℃/35℃典型工况下,平均COP值高11.4%,最大增加了18.3%。实例分析表明,不同方案配置的电机功率差别很大。活塞机比螺杆机方案电机总功率明显偏大,平均大20%,差别最大的总功率增加了42%。因此,在制冷系统设计选型阶段,应对压缩机不同选型方案COP及电机功率进行优化,应认真核算实际需要的电机功率。对于年运行≥3000小时的系统,应选用Y2-E或者YX系列高效节能型电动机。     

Post-accelerator LINAC design for the VECC RIB project

Variable Energy Cyclotron Centre (VECC) is presently developing an ISOL post-acclerator type of RIB facility. The scheme utilises the existing K=130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency quadrupole (RFQ) and LINAC modules for the post-acceleration. The design aspects of these post-accelerator LINAC modules will be discussed in this paper.     

A new description for dispersion

Chang and Slattery (1986) introduced a simplified model for dispersion that contains only two empirical parameters, both of which can be determined in one-dimensional experiments. The traditional model for dispersion (Nikolaevskii, 1959; Scheidegger, 1961; de Josselin de Jong and Bossen, 1961; Bear, 1961a; Peaceman, 1966; Bear, 1972) has three empirical parameters, two of which can be measured in one-dimensional experiments while the third, the transverse dispersivity, must be measured in experiments in which a two-dimensional concentration profile develops. For the common one-dimensional experiment in which the signs of the concentration gradient and of the velocity field are different, the simplified model and the traditional model give identical results. For a one-dimensional experiment in which the signs of the concentration gradient and of the velocity field are at least sometimes the same and for two- and three-dimensional flows, the simplified model of Chang and Slattery (1986) gives results that can differ from those predicted using the traditional model.Only the experimental data of Bear (1961b) and of Yule and Gardner (1978) are sufficiently complete to permit a comparison of the two models. Considering the quality of the experimental data, we can not distinguish between the predicted profiles based upon the simplified model and those based upon the traditional model.     

Simulation of elastic displacement of surface during laser short pulse heating of gold

The laser short pulse heating initiates nonequilibrium heating of the substrate material, which in turn results in the thermal stresses developing in the region below the surface. The surface temperature can be measured possibly through the monitoring of the resulting surface displacement. This requires in detail investigation into the surface displacement and surface temperature rises across the heated spot during the laser short pulse heating process. In the present study, the laser short pulse heating of gold surface is considered and the temperature rise at the surface and elastic displacement of the surface are investigated. The spatial and temporal distributions of surface displacement and surface temperature are predicted and the elastic response of the substrate material due to temperature rise is explored. It is found that the temporal and spatial distributions of the surface displacement do not follow the temperature rise at the surface. Consequently, care should be taken when measuring the temperature rise at the surface by means of monitoring the surface displacement during a laser short pulse heating process.     

Parallel Plate Interferometer with a Reflecting Mirror for Measuring Angular Displacement

A parallel plate interferometer with a reflecting mirror for measuring angular displacement is proposed. A deflection angle of a beam caused by an angular displacement is amplified by use of a reflecting mirror to increase the optical path difference (OPD) in the plane-parallel plate, which provides high sensitivity of the phase measurement. Detection of light transmitted through the plane-parallel plate with a position sensitive detector (PSD) enables high accurate measurement of the initial angle of incidence to the plane-parallel plate with insensitivity to stray light. The improved parallel plate interferometer achieves a measurement repeatability of 10⁻⁸ rad.     

反射式光纤位移传感器应用设计实验

基于光的反射原理并结合光纤传感器的特点,设计了反射式光纤位移传感器应用设计性实验.利用反射式光纤传感器测量微小位移的原理,通过测量输出电压与位移的关系确定工作点,测得表面柤糙程度不同的真假钞的输出信号,从而实现对纸币的真假识别.     

澄清维恩位移定律易混淆的两种形式

对维恩位移定律的两种形式λmaxT=2 899×10-3m·K和Tωmax=2 708×10-12K·Hz-1进行了详细推导和作图,指出λmax≠2πcωmax,因此某些文献用λmax=2πcωmax来联系两种形式是错误的.     

Quantum fluctuations as deviation from classical dynamics of ensemble of trajectories parameterized by unbiased hidden random variable

A quantization method based on replacement of c-number by c-number parameterized by an unbiased hidden random variable is developed. In contrast to canonical quantization, the replacement has a straightforward physical interpretation as a statistical modification of classical dynamics of an ensemble of trajectories, and implies a unique operator ordering. We then apply the method to develop quantum measurement without wave function collapse and external observer a la pilot-wave theory.     

SOI纳米线波导导光机理的物理分析

SOI（silicon-on-insulator）纳米线波导及其器件是近年来光电子学领域研究的重点内容之一．文章从基本的导波光学理论出发,引入古斯一汉森位移理论,对SOI纳米线波导导光的物理机制进行了分析并给出了物理解释和模拟结果．     

90年代天体物理对物理学的挑战（续）

９０年代天体物理对物理学的挑战（续）杨祥（高等教育出版社物理室，北京１００００９）２．３高能天体物理观测项目１）康普顿（γ射线）空间天文台（ＣＧＲＯ）ＣＧＲＯ由美国戈达德（Ｇｏｄｄａｒｄ）空间飞行中心高能天体物理实验室负责研制，于１９７９年开始设计，...