佛山市大气环境影响评价研究

从大气污染源、污染气象条件、大气污染现状入手,运用大气扩散模式对佛山市环境质量现状进行了模拟,并结合2000年城市总体发展规划,预测估算了大气环境的质量和容量,为该市大气污染的治理和环境管理提供了科学依据。     

圆盘型静电涂装机在制造业中的应用

以生产中实际应用的升降式圆盘涂装机为基础,详细介绍了静电涂装的原理,并对我们目前圆盘涂装生产线中存在的问题进行了深入的剖析.静电涂装由于其高效率、高品质,在生产中极大地节省了原材料和劳动力,所以正在得到越来越广泛的关注和应用.     

基于偏微分方程的土壤汞污染源确定算法

利用偏微分方程建立了一种确定土壤表皮汞污染源的三维扩散偏微分方程模型．通过对数据进行回归得到扩散方程,从而确定污染源中心．该方法不但使污染源确定精度提高1．5％,而且得到了该地区汞污染浓度分布函数．     

Bubble entrainment, spray and splashing at hydraulic jumps

INTRODUCTION A hydraulic jump is the sudden transition from a high-velocity, supercritical open channel flow into a slow-moving, sub-critical flow (Belanger, 1840; Bakhmeteff, 1932; Henderson, 1966; Chanson, 2004a). It is characterised by a sudden rise of the free-surface, with some strong energy dissipation and mixing, large-scale turbulence, air entrainment, waves and spray (Fig.1). Early experimental studies of air bubble entrainment were conducted in terms of the quantity of entrain…     

基于嵌入式的自动喷雾系统的设计研究

自动喷雾系统应用于雾化喷涂的核心部件,雾化技术本身虽然能够达到材料节约及喷量控制的目的,但同时也需要具备一定的可靠性和自行数据检测的能力,通过检测到的数据来调整相应的喷剂流量、温度及各类需求型数据,从而达到喷雾控制。将嵌入式应用到自动喷雾系统设计中需要考虑到系统的控制方式、检测方式、安全保障等多方面的问题,因此针对基于嵌入式的自动喷雾系统进行相应的结构及软件设计,以求符合嵌入式系统的多应用型要求。     

两类反应扩散方程的行波解

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｔｏｓｅｅｋｔｈｅａｎａｌｙｔｉｃｓｏｌｕｔｉｏｎｓｆｏｒｇｏｖｅｒｎｉｎｇｅｑｕａｔｉｏｎｓｉｎｋｉｎｅｔｉｃｔｈｅｏｒｙｉｓａｄｉｆｆｉｃｕｌｔｐｒｏｂｌｅｍｆｏｃｕｓｅｄｏｎｂｙｍａｎｙｓｃｈｏｌａｒｓｆｏｒａｌｏｎｇｔｉｍｅ .Ｔｈｅｒｅａｒｅａｌｏｔｏｆｒｅ ｓｅａｒｃｈｗｏｒｋｉｎｔｈｉｓｆｉｅｌｄ ,ｓｅｅＲｅｆｓ .[1,2 ].Ｉｔｉｓｗｏｒｔｈｍｅｎｔｉｏｎｉｎｇｔｈａｔｔｈｅｒｅａｒｅｍａｎｙｒｅｓｕｌｔｓｆｏｒｔｈｅｅｘａｃｔｓｏ ｌｕｔｉｏｎｓｏｆｔｈｅＫ…     

柴油机喷雾特性的电喷控制电路设计

介绍了一种柴油机电控喷油器喷射开启控制系统。为实现柴油机电控喷油器的开启、持续喷油、关闭功能,应用STC12系列单片机构成电控喷油器的控制系统。开启时为使喷油器开启迅速,应用单周期控制技术的IR1150S芯片,产生高压为112 V的高压电源为喷油器供电。试验结果表明,开发的柴油机电控喷油器控制系统符合X光相衬成像技术研究柴油机喷雾雾化机理的要求,喷油开启迅速、喷油持续稳定、关闭干脆。本系统根据设定可实现电控喷油器的单次及多次连续开启,进一步可以推广应用于柴油机喷油器相关环节教学实验中。     

Multidimensional modeling of Dimethyl Ether （DME） spray combustion in DI diesel engine

INTRODUCTION The use of dimethyl ether (DME) as an alterna-tive fuel appears to be a promising approach for si-multaneously minimizing NOx and soot emissionfrom conventional diesel engines. The lowself-ignition temperature of 508 K and the high oxy-gen content of 34.8 percent (mass fraction) are twomajor factors characterizing low soot and unburnedtotal hydrocarbon (THC) emissions. Since the firstintroduction of the concept by Sorenson and Mik-kelsen (19…     

具时滞含扩散项的Nicholson蝴蝶模型的行波解

运用与已知文献不同的方法研究具时滞含有扩散项的Nicholson蝴蝶模型行波解的存在性,所得行波解为相应的不含扩散项时滞Nicholson蝴蝶模型异宿轨的扰动.     

深圳特区大气环境影响评价及环境规划

分析了大气边界层扩散条件、大气污染源分布及预测、大气污染现状。根据O_3、SO_2和NO_x的模拟计算结果,结合城市总体发展规划,进行了大气环境规划工作。     

解常系数线性对流扩散方程的经典R-K法

对流扩散方程是描述粘性流体运动的非线性方程的线性化模型方程,常系数线性对流扩散方程也常用差分法、有限体积法或有限元法来求解,但在处理实际问题时,这些方法往往因为解的精度不高而使计算结果不合理,而采用经典R-K法可以明显提高解的精确度.通过对实际计算结果的比较,该方法解的精度几乎与解析解的精度相同.     

Determination of Diffusion Coefficient and Analysis of Diffusion Factors of Cr(Ⅵ) Ion in Clay Soil

Some laboratory diffusion tests were conducted with diffusion device to determine the diffusion coefficient of Cr(Ⅵ) ion passing through Dalian red clay samples. The concentrations of Cr(Ⅵ) at different places of the samples were then measured spectrophotometrically after a standing time of 1 000 d. A one-dimensional solute transport equation was used to simulate the transport of Cr(Ⅵ) through clay samples. Back-calculation of diffusion coefficient of Cr(Ⅵ) was made with finite difference method. Parametric...     

高阶和式差一型与正幂函数线性微分方程的解法

通过把高阶和式次数差一阶型线性微分方程化为可逐次积分的线性微分方程,找出了求这类方程通解的方法与理论,把所得定理给出了严格的证明,同时通过对正幂函数高阶和式差一型线性方程的研究介绍了它的应用.     

连云港市空气污染特征影响因素研究

连云港市空气质量的主要特征：冬春两季污染明显高于夏、秋两季，海州工业区比市区污染严重，港区污染最轻，日均值呈曲线变化。影响空气质量的主要因素分为气象因素和污染源的排放因素，具体体现为：大气扩散条件的日变化影响，地面风速的影响，地面风向、降水的影响，工业源、流动源的排放影响，扬尘及外来因素的影响。     

Numerical Simulation of Atomization due to Flood Discharges of Hydropower Stations

As a sanitary, reproducible and inexpensive en-ergy resource, the hydroelectric generation has beenincreasingly used in recent years. A great number ofhuge dams have been constructed in the narrow gor-ges, with the height of around 300 m and the flooddischarging powers ranging from10 billion to100 bil-lion W. The maximum unit discharges all exceed 200m3/(s·m). With the characteristics of flood dis-charge such as high head, large discharge, narrowgorges and high frequency, the existing dams ha…     

煤系高岭土脱硅率的数学表达式浸出动力学

通过分析煤系高岭土的脱硅率与脱硅温度的实验数据,推出了煤系高岭土的脱硅率与脱硅温度的曲线方程;通过对煤系高岭土的浸出动力学数据的处理,判定该工艺的浸出工序属于内扩散控制,符合收缩核模型;最后通过Arrhenius经验公式,得到Arrhenius线性图,求得活化能.     

二次方三项式线性齐次微分方程的解法

通过把线性齐次微分方程x2y(n) 2nxy(n-1) n(n-1)y(n-2)=0化为可逐次积分的线性微分方程,找出了它的通解形式,给出了严格的证明,并将其推广,得到x2y(n) (x2 2nx)y(n-1) [2(n-1)x n(n-1)]y(n-2) (n-1)(n-2)y(n-3)=0的通解.     

含幂与二项式系数线性微分方程解法探讨

通过把系数含有幂与二项式系数的常系数线性微分方程化为可逐次积分的线性微分方程,找出了求这类方程通解的方法与理论,把所得定理给出了严格的证明,并通过实例介绍了它的应用。     

负一次幂交错级数型的高阶和式差一型线性微分方程

通过把系数含有负一次幂与排列数的交错级数型的高阶和式差一型线性微分方程化为可逐次积分的线性微分方程，找出了求这类方程通解的方法与理论，把所得定理给出了严格的证明，并通过实例介绍了它的应用。     

Determination of Diffusion Coefficient and Analysis of Diffusion Factors of Cr（Ⅵ） Ion in Clay Soil

Some laboratory diffusion tests were conducted with diffusion device to determine the diffusion coefficient of Cr(Ⅵ) ion passing through Dalian red clay samples. The concentrations of Cr(Ⅵ) at different places of the samples were then measured spectrophotometrically after a standing time of 1 000 d. A one-dimensional solute transport equation was used to simulate the transport of Cr(Ⅵ) through clay samples. Back-calculation of diffusion coefficient of Cr(Ⅵ) was made with finite difference method. Parametric analysis was conducted to simulate variations in soil dry density, temperature, pH and standing time. The results show that the method used in this paper is simple and effective. The diffusion coefficient of Cr(Ⅵ) in Dalian red clay varies from 1.50×10-7 cm2/s to 2.08×10-7 cm2/s. After 1 000 d diffusion, the concentration of the source solution drops down to 1.27 mg/L from 62.5 mg/L, and the diffusion distance is only 3.5 cm. Under the assumption that diffusion coefficient is constant, the diffusion effect becomes more obvious with lower density, lower temperature, higher pH value, and much more time.