Highly Stereoselective and Efficient Hydrosilylation of Terminal Alkynes Catalyzed by

With [RuCl(2)(p-cymene)](2) as a catalyst, extremely high regio- and stereoselectivity was observed in the hydrosilylation reaction of various terminal alkynes under mild conditions to afford beta-(Z)-vinylsilanes in excellent yields. A dramatic directing effect was also observed when alkynes having a hydroxyl group at the beta position to the triple bond were employed as a substrate, and in these cases regioisomeric alpha-vinylsilanes were generated with excellent selectivity.     

在“画法几何及机械制图”课程教学中如何培养学生的能力

本文从高等教育必须加强学生各种能力培养的观点出发，阐述了在“画法几何及机械制图”课程教学活动中如何培养大学生的自学能力、空间想象能力、逻辑思维能力、读图和绘图能力的途径和方法上所作的探索和体会。     

消费者连续统集合下一种投入产出经济的均衡和一般均衡价格

本给出了一个经济模型把跨期间的一般均衡理论和neo-Ricardian的生产价格理论联系起来，并改进了Roce-Anne Oana模型[1][2]。即把消费有限改变消费连续统，并在Rose-Anne Dana模型的基础上，加了条件C.4和C.7，得出了两个重要的结果：（1）在标准条件下，此模型有一均衡使得每一个生产的每期最大利润是相等的；（2）如考虑生产价格是稳定价格；且等于最大利润；则在适当的条件下，这样的价格系统是存在且唯一的，而所定义的均衡的非折扣的价格序列收敛于生产价格。因此均衡价格依赖于技术和消费特征，但在取极限时，有关价格仅依赖于技术。     

Dual properties of spacetime under an alternative Lorentz transformation

In flat spacetime, the fourth space coordinate in special relativity (SR) is equivalent to the coordinate time t_E. We will show, however, that this definition of physical time is not unique. Another natural choice of coordinate time, t_A, with absolute synchronization is allowed. Spacetime would exhibit dual properties, namely relativistic and absolute. In an arbitrary inertial frame, the relationship of the above two kinds of coordinate time corresponds to a resynchronization, and the Lorentz transformations can be written in an alternative form, which is called the generalized Galilean transformation (GGT). Although the absolute property is still hidden in nearly all types of experiments, the advantages of the above approach are as follows: (1) It will give us a deeper understanding of SR, including the basis of length contraction, time dilation and the interaction between moving objects and the physical vacuum. (2) It will provide a wider research domain than SR; for example, superluminal motion is predicted and has obtained growing experimental support.     

Random phase-coded multiplexing of hologram volumes using ground glass

We apply an encoding method, random phase-coded multiplexing, to volume hologram multiplexing and demonstrate the recording of 100 holograms in LiNbO₃: 0.01% Fe. A theory is developed to interpret the noise generated by this method, and a computer simulation is provided for direct comparison.     

Image formation for two-dimensional periodic object using Talbot effect

The conditions under which the information inside each subcell of a two-dimensional (2D) object, periodic in orthogonal directions, is replicated throughout all the subcells of the unit cell are obtained. Relative-phase relationship among all the subcells depends only on the number of subdivision but not the length-to-width ratio of the unit cell. From this relationship, the wave amplitude at all the subcells is calculated by superposition of the information from all the subcells in the orginal object. A 2D object periodic in nonorthogonal directions can be decomposed as a set of laterally shifted 2D objects which are periodic in orthogonal directions. Hence, the image formation problem for nonorthogonally periodic object can be solved directly from the superposition of results for the laterally shifted, orthogonally periodic ones.     

Stability conditions for a pipeline polling scheme in satellite communications

This paper considers the unknown stability conditions of a pipeline polling scheme proposed for satellite communications. This scheme is modelled as a cyclic-service system with limited service and reservation. The walk times and the maximum number of services to be performed during each polling are dependent on the queue lengths of the stations. The main result is the derivation of the necessary and sufficient stability conditions of the system. Our approach is to map the multi-dimensional stability problem into many 1-dimensional stability problems through the concept of the least stable queue. The least stable queue is one that will become unstablefirst when the system load increases in some parameter region. The stability of the least stable queue thus implies stability of the system. The stability region for the whole system is then the union of the queue stability regions of all the least stable queues that are obtained through dominant systems and Loynes' theorem. We also propose a computable sufficient condition that is tighter than the existing result and present some numerical results.     

Experimental observation of a striking similarity between quantum hall transport coefficients

The derivative of the Quantum Hall resistance, ρ_xy, with respect to the carrier density, n, has been measured for a two-dimensional electron gas in a GaAs-Al_xGa_1?xAs heterostructure, as a function of magnetic field. dρ_xy/dn exhibits a remarkable similarity to the diagonal resistivity, ρ_xy, to the extent that one is almost directly proportional to the other. Our result suggests the possibility of a fundamental connection between the two quantities.