Radiation detector made of a high-quality polycrystalline diamond

Radiation detector was made of a high-quality CVD polycrystalline diamond composed of frost column like structure diamond grains, and induced charge distribution spectra and drift velocities were measured by using alpha particles. As a result, the CVD polycrystalline achieved maximum induced charge of 83% of HP/HT type IIa diamond. Moreover, the CVD crystal had lower charge loss on electrons compared with the HP/HT type IIa diamond. Drift velocities of electrons and holes were v_e = 7.7 × 10⁴ and v_h = 7.3 × 10⁴cm/s at an electric field of 20 kV/cm, respectively. In addition, response function measurement for 14 MeV neutrons was carried out.     

Novel Hyperbranched predominantly Alternating Copolymers Made From A Charge Transfer Complex monomer pair of p-(chloromethyl)styrene and Acrylonitrile via Controlled Living Radical Copolymerization

Summary Novel hyperbranched copolymers were successfully synthesized by the controlled charge transfer complex inimer and living radical copolymerization of p-(chloromethyl)styrene (PCMS) and acrylonitrile (AN). The resulting copolymers were characterized by SEC, NMR, FTIR, DSC and elemental analysis etc.. The influences of reaction conditions, such as the polymerization temperature, the catalyst (CuBr) concentration and the monomer ratio, on the resulting copolymers were investigated in detail. The monomer reactivity ratios were evaluated to be r_PCMS=0.937 and r_AN=0.088 respectively by the Fineman-Ross method. The higher are the polymerization temperature and the ratio of catalyst to monomer, the higher is the branching degree of the resulting copolymer. When the amount of monomer AN was used in excess than that of the monomer PCMS in the raw feed, the hyperbranched predominantly alternating copolymers HP[PCMS-co-AN] could be obtained. These hyperbranched copolymers were successfully used as functional macroinitiators to synthesize the star-shaped poly(PCMS-co-AN)/poly(MMA) block copolymers.     

The Metaflow architecture

The Metaflow architecture, a unified approach to maximizing the performance of superscalar microprocessors, is introduced. The Metaflow architecture exploits inherent instruction-level parallelism in conventional sequential programs by hardware means, without relying on optimizing compilers. It is based on a unified structure, the DRIS (deferred-scheduling, register-renaming instruction shelf), that manages out-of-order execution and most of the attendant problems. Coupling the DRIS with a speculative-execution mechanism that avoids conditional branch stalls results in performance limited only be inherent instruction-level parallelism and available execution resources. Although presented in the context of superscalar machines, the technique is equally applicable to a superpipelined implementation. Lightning, the first implementation of the Metaflow architecture, which executes the Sparc RISC instruction set is described     

Computerized facility layout design

The paper describes a computerized facility layout designer, COMLAD II, for plant layout development. Besides developing an efficient layout, COMLAD II has useful features which allow fixing the departments, changing the shape of the departments and changing the length and width dimensions of the overall layout.     

多级网络多处理机系统的性能评估

本文建立了多级网络(δ-网)多处理机系统的马尔柯夫模型,为系统结构参数和任务粒度的选择提供了依据。文中分析了处理机数目、网络结构参数和任务粒度对系统性能的影响,并对模型计算结果和仿真结果作了比较。     

IBM RISC System/6000: architecture and performance

The IBM RISC System/6000, a superscalar microprocessor, is presented. The architecture of this processor has its instruction set specifically designed for a superscalar machine containing three independent units-branch, fixed-point, and floating-point. The design also emphasizes high-performance floating-point operations. The design principles are to offer maximum overlap of the three functional units, avoid dead cycles, and define instructions that can (for the most part) be completed at a rate of one per cycle. The branch cycle, fixed- and floating-point units, cache management, and performance are described. Benchmark results are given     

Theory of residence-time control by output feedback

The problem of residence-time control by the observer-based output feedback is formulated and solved for the case of linear systems with small additive input noise. Both noiseless and noisy measurements are considered. In the noiseless measurements case, it is shown that the fundamental bounds on the achievable residence time depend on the nonminimum phase zeros of the system. In the noisy measurements case, the achievable residence time is shown to be always bounded, and an estimate of this bound is given. Controller design techniques are presented. The development is based on the asymptotic large deviations theory. Recommended by T K. Caughey     

Surface chemistry and suspension stability of oxide-nitride powder mixtures

The effect of bimetallic oxide sintering aids on the colloidal stability of homogeneous (surface-coated) and heterogeneous (mechanically mixed) silicon nitride powder mixtures in aqueous solution was studied by acoustophoretic analysis. While the surface charge generation and colloidal stability of single-phase and oxide-coated silicon nitride powder mixtures may be described according to the site dissociation model of amine and hydroxyl surface groups, the surface charge observed in heterogeneous multiphase powder mixtures is associated with the adsorption of soluble metal ion hydroxocomplexes on the nitride particles. Segregation of the mixtures by heteroflocculation, which causes the formation of agglomerates and microstructural defects upon sintering, may be avoided by generation of a threshold surface potential of equal sign on all powder constituents at a pH where the metal hydroxide dissolution is subcritical.