纳米技术的发展与市场(续上期)

综述了纳米科技目前世界发展状况、发达国家争夺主导权的激烈竞争以及世界市场状况,叙述了纳米技术在电子信息、生物医药等各方面的应用,最后,概括介绍了纳米材料的制备方法。     

我国区域公用品牌基本状况分析

目前关于区域公用品牌的概念内涵、驱动因素、形成机理、创建模式、价值评价等多方面研究,都建立在区域公用品牌基本状况的研究基础之上,而如今关于区域公用品牌基本状况的研究普遍存在不充分、不全面的问题。有鉴于此,本文基于数据统计,从数量分布状况、区域分布状况、品类分布状况、品牌价值分析、市场份额分析等五个维度对我国区域公用品牌的基本状况进行了分析研究,期望对我国区域公用品牌的基本状况进行更清晰的刻画。通过五个维度的分析,发现我国区域公用品牌基本状况呈现出如下几个特点：第一,数量状况方面,区域公用品牌的总量呈现逐年增长态势;第二,区域分布状况方面,区域公用品牌表现出集中分布的特征,同时,南方省份、经济大省、农业大省的品牌数量更多;第三,品类分布方面,大约超过60%的区域公用品牌分布在“果品”、“蔬菜”、“粮食”三大品类当中,这样的分布特点与消费者的消费频率高度相关;第四,品牌价值方面,品牌价值高的品牌更多地分布于“果品”与“粮食”两大品类当中,且头部品牌贡献了主要的品牌价值;第五,市场份额方面,区域公用品牌产品的市场份额逐年稳步提升,同时,区域公用品牌产品具有明显更高的溢价且表现出显著的外溢效应...     

建筑施工工地的用电安全措施

从建筑施工工地的外部环境、人员状况、等电位联结状况等,浅述了建筑施工工地存在着电气危险隐患,以及必须采取的用电安全措施。     

锅炉风粉监测设计

为提高锅炉热效率,对锅炉燃烧状况进行实时监测,引进了一次风粉混合物监测设计,将混合物的流速、浓度进行计算、显示、报警,提示操作员迅速调整操作方式,确保最佳燃烧状况。     

地源热泵中央空调的多种设计方案及其特性分析

根据地埋管地源热泵中央空调夏、冬季运行,对地层岩土体累积排热量、累积取热量的平衡状况及我国的地域气候状况,提出了9种设计方案,并逐一论述了各自的特性及其适用性。     

基于Mask R-CNN的污泥热解工艺状况智能诊断

针对目前污泥热解工艺状况判断主观性强、人力成本高、反馈效率低等问题,结合深度学习理论在诊断预测领域的优势,提出了基于掩膜区域卷积神经网络（Mask R-CNN）的污泥热解状况智能诊断模型。以某污泥处理厂市政污泥处置项目为例,采集污泥热解出渣图像数据并构建规范化样本数据库,根据出渣图像所反映的工艺优劣状况,将样本数据分为5类状态,对模型进行训练与测试。实验结果表明,所构建模型实现了对污泥热解工艺状况的有效学习与诊断,为推动低碳高效智能的污泥处置模式提供了技术支持。     

重庆市居住建筑室内环境测试与研究

通过对重庆市具有代表性的20户住宅进行室内环境测试,分析了重庆市居住建筑在测试日期内的室内热环境、声环境、光环境及空气品质状况,为重庆市居住建筑室内环境状况的进一步改善提供了基础数据。     

蔬菜商品标准的实施状况,存在问题和建议

蔬菜商品标准的实施状况、存在问题和建议蔬菜商品标准及实施状况调研组一、蔬菜商品标准实施状况我国蔬菜行业经过多年来的产销体制改革，在蔬菜生产发展、繁荣蔬菜市场、满足蔬菜消费以及采取新的流通组织形式和营销方式等方面都发生了很大变化，取得了可喜的成绩。同时...     

企业科技状况评价概念述评

科技工作对企业的重要性推动了对企业科技状况评价研究的发展,对企业科技状况进行评价能够更好的制定企业科技发展战略,指引企业科技进步的方向。但目前对于企业科技状况评价的研究较多,仅概念就存在多种名称或提法,本文对科技能力评价、科技进步评价等多种类似的概念进行探析,找出最适合衡量企业的科技状况的概念。     

光学透镜用合成树脂材料进展

本文主要介绍了合成树脂光学透镜材料CR－39的应用现状、发展状况以及其它高折射率合成树脂光学透镜材料的研制、开发状况。     

Interaction between crack and arbitrarily shaped hole with stress and displacement boundaries

The interaction between a crack and an arbitrarily shaped hole under stress and displacement boundaries in an infinite plane subjected to a remote uniform load is studied. The Green's functions of a point dislocation for the problems are derived and are then used to analyze the interaction problem. The superposition principle is employed to reduce the original problem to two subsidiary problems. The complex stress functions of each problem are composed of two parts, in which the second parts are always holomorphic. Using analytical continuation in conjunction with rational mapping function, the stress functions are obtained in closed form. The interaction of a hole or an inclusion with a crack is solved using dislocations to model the crack and solving a system of singular integral equations. Stress intensity factors for crack tips and stress concentration factors for inclusion corner are determined and plotted for various cases. The affecting ranges of hole and inclusion are investigated.     

Amplitude-squared and amplitude-cubed squeezing in stimulated Raman and in spontaneous Raman scattering

Coherent light coupled to a third-order nonlinear medium is responsible for spontaneous and for stimulated Raman processes. The analytical solutions up to second order in coupling constants of various field modes for spontaneous Raman and for stimulated Raman processes are utilized to obtain the amplitude-squared and amplitude-cubed squeezing of the input coherent light. The amplitude-squared and amplitude-cubed squeezing are completely ruled out for all modes for spontaneous Raman processes. For stimulated Raman processes, we observe that the squeezing for amplitude-squared and amplitude-cubed are possible for pump and for vibrational phonon modes. It is found that the percentage of higher ordered amplitude squeezing decreases with the increase of the orders. The squeezing in Stokes and in anti-Stokes modes are ruled out even for stimulated Raman processes.     

大气折射和大气色散的数值计算及结果分析

介绍了大气折射和大气色散的概念，推导了它们的计算公式。通过数值迭代的方法计算了一定条件下各种模型的大气折射和大气色散值。分析得到了各种模型下大气折射和大气色散的差异以及大气压、气温、观测站点海拔和工作波段对大气色散的影响。     

Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air

New formulations for the viscosity and thermal conductivity for nitrogen, oxygen, argon, and air are given. Air is treated as a pseudo-pure fluid using an approach adopted from previous research on the equation of state for air. The equations are valid over all liquid and vapor states, and a simplified cross-over equation was used to model the behavior of the critical enhancement for thermal conductivity. The extrapolation behavior of the equations for nitrogen and argon well below their triple points was monitored so that both could be used as reference equations for extended corresponding states applications. The uncertainties of calculated values from the equations are generally within 2% for nitrogen and argon and within 5% for oxygen and air, except in the critical region where the uncertainties are higher. Comparisons with the available experimental data are given.     

The shape and stability of wall-bound and wall-edge-bound drops and bubbles

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.     

Translational partition functions and equilibrium constants of atomic and molecular particles

Some special features of the calculation of partition functions for the objects possessing finite dimensions are considered. It is shown that atomic, molecular, and more extended clusterlike objects are subject to certain spatial limitations related to the initial assumptions employed in the statistical approach. The values calculated for a material point or an object such as electron are overstated when applied to atomic particles. The classical expressions for the kinetic and statistical equilibrium constants of the reactions of formation and dissociation of diatomic molecules are compared. The observed discrepancies are eliminated by introducing corrections into formulas for the translational partition functions.     

轮轨摩擦碰撞及脱轨的研究

研究了轮轨的三维摩擦碰撞问题,建立了碰撞动力学模型,导出了碰撞过程轮轨接触点切向运动的解析式和车轮跳起高度的表达式,推导了轨轨二维摩擦碰撞脱轨的判别准则,最后,对轨轨碰撞脱轨进行了实例计算,分析了轮对的横向冲击速度、摇头角、轮缘角、轮轨摩擦系数和垂向力等对脱轨的影响。     

Diffraction and refraction of surface waves using finite and infinite elements

The wave problem is introduced and a derivation of Berkhoff's surface wave theory is outlined. Appropriate boundary conditions are described, for finite and infinite boundaries. These equations are then presented in a variational form, which is used as a basis for finite and infinite elements. The elements are used to solve a wide range of unbounded surface wave problems. Comparisons are given with other methods. It is concluded that infinite elements are a competitive method for the solution of such problems.     

环境与材料

本文论述了自然环境与社会环境对材料的影响与作用。首先介绍了环境与作为系统的材料之间的关系。给出了材料的定义和判据。分析了社会大环境与经济体制对经济持续发展及材料事业发展的影响。并依次讨论了人类处理材料与自然环境关系的三个阶段：一、适应和改变；二、学习和利用；三、保护。其中还介绍了失效物理与环境控制、耗散结构、智能材料和环境意识材料。最后以诗一首，总结材料工作者对环境应有的五个正确对待