A study of time over threshold (TOT) technique for plastic scintillator counter

A new charge measurement method, time over threshold (TOT), has been used in some gas detectors lately. Here TOT is studied for TOF system, made of plastic scintillator counter, which can simplify the electronics of the system. The signal characteristics are measured and analyzed with a high quality oscilloscope, including noise, pedestal, signal amplitude, total charge, rise time and the correlation between them. The TOT and charge are related and can be fitted by some empirical formula. The charge measurement resolution by TOT is given and this will help the design of TOF electronics.     

Iron Nanoparticles in Severe-plastic-deformed Copper

Superparamagnetic iron nanoparticles with a size of a few nanometers were produced in copper by severe plastic deformation. In a isochronal annealing experiment near a temperature of 450K, which corresponds to the temperature of structural relaxation and the first step of grain growth (from 128 to 150nm) of submicrocrystalline copper, an abrupt increase in the magnetic susceptibility is detected. This increase is shown to be due to iron nanoparticles increasing in size from 2.8 to 3.3nm. The vanishing of the ferromagnetic contribution by iron nanoparticles observed at 850K, well below the Curie temperature of iron, is due to the dissolution of nanoparticles in plastically deformed copper.     

弹塑性结构在外载和温度作用下的安定分析

本文在考虑外载和温度的缓慢变化下，提出了一个新的运动安定定理。同时，在此基础上，又导出了既简单又适用的增量破坏准则．文末也以实例说明了它的应用。     

Nonleptonic decay matrix elements in the variable pressure bag model

The consequences of the variable pressure bag model for the nonleptonic decays of hyperons and Ω⁻ are investigated. Though the order of magnitude and the relative sign for the various decay amplitudes are correctly reproduced, the overall results are small by a factor of 2 to 4, indicating that the theoretical predictions are strongly dependent on the model parameters.     

Dynamic Behavior of Rigid–Plastic Sector Plates

The paper studies the dynamic behavior of perfect rigid-plastic plates in the form of a sector with hinged or clamped sides under short-term intensive loads. Two dynamic deformation mechanisms are demonstrated. The dynamic equation is derived for each of the mechanisms. The realization conditions for the mechanisms are analyzed. Analytical expressions are derived for the ultimate (high) loads and the maximum residual deflection. Numerical examples are given     

基于最小加速度原理的刚塑性动力问题

应用有限变形的最小加速度原理，推导出了小变形或有限变形构件受到刚性飞射物撞击时的刚塑性运动方程，指出该方法具有直接、简捷和可靠的特点。     

孔洞受压的统一极限分析

采用俞茂宏统一强度理论分别就平面应变和平面应力总是对受压孔洞进行了极限分析，得到了各自的统一解形式。以往的基于Ｔｒｅｓｃａ、Ｍｉｓｅｓ、双剪屈服准则以及Ｍｏｈｒ－Ｃｏｕｌｏｍｂ强度理论的极限解均为本文统一解的特例。此解可以适应于广泛的不同性质的各灯材料，合理也得出不同材料的相应解。     

Global Existence for Rate-Independent Gradient Plasticity at Finite Strain

We provide a global existence result for the time-continuous elastoplasticity problem using the energetic formulation. For this, we show that the geometric nonlinearities arising from the multiplicative decomposition of the strain can be controlled via polyconvexity and a priori stress bounds in terms of the energy density. While temporal oscillations are controlled via energy dissipation, the spatial compactness is obtained via regularizing terms involving gradients of the internal variables. Dedicated to Sir John Ball on the occasion of his 60th birthday.     

Nucleon-nucleon interaction with tensor forces in the quark compound bag model

A model forN-N interaction proposed earlier by two of us (VSB and VKG), has been extended to incorporate the tensor component of the nuclear force. Based on the quark compound bag model (QCB), the nucleon-nucleon potential has a short range repulsive core which is non-local and has a characteristic energy dependence and is expressed in terms of the parameters relating to the six-quark compound bag. To account for the low energy properties, this repulsive core interaction is supplemented by a phenomenological non-local potential containing both central (S-wave) and tensor components and operates only outside the QCB. Using this model, we analyse and compare the results with the experimental data for the electromagnetic form factors of the deuteron, theD-state observables, such as the quadrupole moment, theD-state probability, and theD/S ratio along with then-p scattering phase shifts up to about 400 MeV.     

Degradation of aliphatic-aromatic copolyesters by bacteria that can degrade aliphatic polyesters

The degradation activities of bacteria that can degrade aliphatic polyesters on various aliphatic-aromatic copolyesters (PBSTIL, PBST, and Ecoflex™) were investigated. Among the bacteria examined, strain TB-71 showed the best degradation activity. An HPLC analysis of the degradation products revealed that PBST55 and Ecoflex™ are degraded into monomers by strain TB-71. In the case of PBSTIL, an unknown peak was detected by the HPLC analysis and was considered to be derived from water-soluble oligomers containing isophthalic acid segments. This finding seemed to be attributed to the chemical structure of the aromatic segments of the copolymers.