Gini Index for Cities: A Preliminary Study on Regional Differences of Chinese City Size Distribution

City size distribution is of interest because of a number of key stylized facts, including notably Zipf's law for cities and the importance of urban primacy. But a new and more efficient method Gini index can be used for calculating regional city size distribution. This paper begins by developing a calculation method for the Gini index, dividing the whole country into 26 areas and then calculating each area's Gini index value. Based on these calculation results, this paper gives a preliminary study on regional differences of its city size distribution and the dynamics.     

基于激光快速成形技术的快速工/模具制造

概括了基于激光快速成形技术的快速工/模具制造的两种方法——间接法和直接法,对两种工/模具制造技术作了较具体的介绍,并分析了其特点.     

Roadside dusts and soils contamination in Cincinnati,Ohio, USA

Roadside dusts and soils were collected from various nonindustrial districts in Cincinnati, Ohio, USA, and analyzed for lead and copper contents. Results showed that the recent lead phase-down action has reduced the level of lead, but the concentrations of both metals are still higher than the background levels for normal soil. Elevated concentrations of copper in heavily traveled highways were noted, suggesting that much of the copper pollutants is probably of automotive origin. The concentration of lead was found to vary with housing age, and higher levels of contamination in the older neighborhoods were observed. This result is probably ascribable to the accumulation of residues from leaded gasoline and lead-based paint in the past and the use of coal fire for space heating in older houses.     

聚合硫酸铁絮凝剂中痕量镉测定的研究

研究了测定聚合硫酸铁絮凝剂中痕量镉的新方法。本法是利用离子选择性电极测定聚合硫酸铁絮凝剂中的镉。研究内容包括测定条件、干扰试验、干扰排除等。本法不需调整 p H值 ,设备简单 ,操作简便 ,测定快速。在测定条件下 ,本法的线性范围为 1 .0× 1 0 - 2 ～ 9.0× 1 0 - 7,回收率为 91 %～ 1 0 7% ,适宜的 p H值范围为 3- 6。本法用于了实际样品测定 ,结果满意。     

PCrNi3MoVA钢动态再结晶晶粒尺寸的影响因素

此文利用Formastor-Press热模拟试验机研究了Z参数、奥氏体起始晶粒尺寸D_0和应变ε对PCrNi3MoVA铜动态再结晶晶粒尺寸D_(dyn)的影响。通过对试验数据进行分析发现以下规律:①1nD_(dyn)=a+blnZ,②lnD_(dyn)=c+dlnD_0;③lnD_(dyn)=e+flnε 10％≤ε≤40％,其中a、b、c、d、e、f为不同的常数,据此,此文采用线性回归方法获得了上述这些常数的值。     

固定化细胞技术及应用于废水处理的最新进展

本文简要介绍了用于废水处理的固定化细胞技术及应用此技术进行废水处理的七个领域的最新成就。     

混凝气浮-推流式活性污泥-深度处理法处理染色废水

介绍了混凝气浮-推流式活性污泥-深度处理法在染色废水工程中的应用，分析了工程的设计及运行的情况。实践表明，混凝气浮预处理可以有效去除色度、悬浮物和部分有机物，提高抗冲击负荷能力；推流式活性污泥法有较高的处理效率，经深度处理后，废水达标排放。     

地理信息学与煤矿环境管理

以地理信息系统，全球定位系统，遥感为主体和核心的地理信息学在煤矿环境管理中有着广泛的应用。本文在对地理信息学及其应用于煤矿环境管理的优点进行简要介绍和分析的基础上，对其在煤矿环境信息采集，监测，评价，治理等方面的应用进行了系统的探讨。     

HPLC-UVD/FLD测定海洋环境样品中PAHs的研究

建立了ＨＰＬＣ－ＵＶＤ／ＦＬＤ测定海洋环境样品中ＰＡＨｓ的分析方法，探讨了紫外可变波长，荧光激发／发射波长，梯度斜率对ＰＡＨｓ响应因子和分离度的影响，得出了仪器的重复性，线性区间，检出限以及不同层析柱的回收率，测定了沉积物和贻贝样品中的ＰＡＨｓ。结果表明，方法的精密度和准确度是令人满意的。