基于CCD和PC机的高精度刚度检测系统的研制

根据某类球头杆零件的高精度刚度检测的实际需要 ,开展了将 CCD技术应用于零件刚度检测领域的研究 ,并研制出一套基于 CCD和 PC机技术的此类球头杆零件的高精度刚度检测系统。认为 CCD技术在工业刚度检测领域具有良好的应用前景。     

Global hysteresis in ferroelectrics with incommensurate phases

A review of the basic experimental results connected with the formation of long-living metastable states in the incommensurate phases of ferroelectric crystals and related phenomena is given. The interpretation and appropriate physical mechanisms underlying the global hysteresis phenomena associated with these states are considered.     

用于测量熔合反应的静电偏转板介绍

An electrostatic deflector for separating the fusion evaporation residues from the beam-like products in heavy ion reactions was installed. The evaporation residue separation and identification with the electrostatic deflector setup was tested with the reaction ^32S＋^96Zr at several energies. The fusion evaporation residues and the beam-like particles were well separated after the electrical separation and the experimental fusion cross section obtained from the angular distribution is in good agreement with the calculated value well above the Coulomb barrier. This confirms the reliability of the setup.     

平面团簇稳定结构的蒙特卡罗树搜索

以平面团簇为例提出了一种结合结构识别和蒙特卡罗树技术搜索稳定结构的新方法.体系原子之间的相互作用由两类模型势能函数来描述:Lennard-Jones二体势函数与基于Lennard-Jones势的三体势函数.考虑可能的三角晶格碎片作为候选结构,引入编号策略对结构进行快速识别,并运用蒙特卡罗树搜索研究稳定结构随着原子数增大的演化过程;对于能量较低的候选结构,进一步采取局域优化来获得对应体系的稳定结构.计算表明,Lennard-Jones二体势函数对应的三角晶格团簇更稳定;在特定的参数下,三体势函数对应的六角晶格团簇更稳定.结合结构识别和蒙特卡罗树搜索可以对候选结构空间进行高效扫描,在较短时间内更容易搜索到稳定的团簇结构,并可以与第一原理计算结合实现材料的结构预测.     

一个关于肿瘤治疗的自由边界问题的数学分析

§1Introduction Avarietyofpartialdifferentialequationmodelsfortumorgrowthortherapyhave beendevelopedinthelastthreedecades[see2,3,16-18,21-26].Mostofthosemodelsare informoffreeboundaryproblems,andareverydiversified.Rigorousmathematical analysisofsuchfreeboundaryproblemshasdrawngreatinterest,andmanyinteresting resultshavebeenestablished[4-15].Inthispaperwedealwithamathematicalmodeldescribingtumorchemotherapy.In thismodelthetumorisviewedasdenselypacked,radially-symmetricsphereofradiusR(t)contain…     

Global Weak Solutions for the Weakly Dissipative Camassa-Holm Equation

In this paper we prove the existence and uniqueness of global weak solutions to the weakly dissipative Camassa-Holm equation.     

A generalized preimage theorem in global analysis

The concept of locally fine point and generalized regular value of a C¹ map between Banach spaces were carried over C¹ map between Banach manifolds. Hence the preimage theorem, a principle constructing Banach manifolds in global analysis, is generalized.     

Nanotechnology and the need for risk governance

After identifying the main characteristics and prospects of nanotechnology as an emerging technology, the paper presents the general risks associated with nanotechnology applications and the deficits of the risk governance process today, concluding with recommendations to governments, industry, international organizations and other stakeholders. The International Risk Governance Council (IRGC) has identified a governance gap between the requirements pertaining to the nano- rather than the micro-/macro- technologies. The novel attributes of nanotechnology demand different routes for risk-benefit assessment and risk management, and at present, nanotechnology innovation proceeds ahead of the policy and regulatory environment. In the shorter term, the governance gap is significant for those passive nanostructures that are currently in production and have high exposure rates; and is especially significant for the several ‘active’ nanoscale structures and nanosystems that we can expect to be on the market in the near future. Active nanoscale structures and nanosystems have the potential to affect not only human health and the environment but also aspects of social lifestyle, human identity and cultural values. The main recommendations of the report deal with selected higher risk nanotechnology applications, short- and long-term issues, and global models for nanotechnology governance.