137Cs budget during the period of 1960s in a small drainage basin on the Loess Plateau of China

A sediment profile with a thickness of 28.12 m in a failed reservoir in a small catchment of the Yuntaishan Gully in the Loess Plateau of China consisted of 44 flood couplets deposited during the period from 1960 to 1970 with total volume of 2.36 x 10(6)m(3). Specific sediment yields for a flood event varied from 300 t km(-2) to 14,400 t km(-2) and annual sediment yields varied from 2500 t km(-2) in 1966 to 40,000 t km(-2) in 1964 with a mean value of 12,700 t km(-2)a(-1) for the period. Average annual (137)Cs concentrations of the sediments increased from 0.92 Bq kg(-1) in 1960 to 4.82 Bq kg(-1) in 1963, then decreased to 1.53 Bq kg(-1) in 1970. The total (137)Cs activity in the reservoir sediments was 9.22 x 10(9) Bq, which accounted for 31.9% of the total (137)Cs fallout precipitation of 2.89 x 10(10) Bq within the catchment during the period. The proportion of the (137)Cs loss from the catchment to the (137)Cs fallout precipitation within the catchment in a year varied between 8.01% and 66.8%, and it was 20.9% for the peak (137)Cs deposition year of 1963 and 52.0% in 1964. By analysis of the (137)Cs budget in the catchment for the (137)Cs peak precipitation period from 1962 to 1964, the (137)Cs surface enrichment coefficient Gamma should be much less than 0.23. And for calculation of soil losses on the cultivated land in the inter-gully area by using the Mass Balance Model II, the value of Gamma should be 0.05-0.1.     

Attack vulnerability of self-organizing networks

There are several self-organizing networks in the real world, and these networks severely affect the development of the modern society. This paper investigates the vulnerability of self-organizing networks subject to malicious attacks according to a new framework. Assuming the initial load of node i as L_i=αk_i+(1-α)∑_j∈Γik_j with k_i and Γ_i being the degree and the set of neighbor nodes of the node i, where α is a tunable parameter and control the strength of the initial loads of nodes. The node with the maximum degree is considered as the attacked node, and with the changes of the parameter α, cascading failures will be investigated in this paper. Local redistribution rule has been adopted to study the cascading breakdowns of the US power grid and IEEE-118 networks. Additionally, the capacity of the node i is defined as C_i = (1 + β)L_i, the critical threshold β_c of the US power grid and IEEE-118 networks will be obtained from the evolutional process of cascading failures. Finally, an optimal design of US power grid network is given in this paper.     

秦皇岛市海港区污水排放系统现状分析

本文从秦皇岛海港区污水排放系统现状分析入手,指出了污水排放系统中存在的问题,并提出了污水排放系统发展的建设。     

离子色谱法电化学检测复合甜味剂和饮料中的甜味素

提出了一种以离子色谱法分离,积分安培法检测复合甜味剂和饮料中甜味素的新方法。以ＤｉｏｎｅｘＡＳ４Ａ－ＳＣ柱为分离柱,２７．５ｍｍｏｌ．ｌ＾－１ＮａＯＨ为淋洗液等度淋洗,积分安培电化学检测。     

三峡库区扩种龙眼荔枝的适宜性分析

荔枝与龙眼系亚热带水果,集中分布于闽粤两省,三峡库区上段河谷两侧也有零星分布,是该类水果分布的最北界。这类水果在训区栽培始于汉唐时代,并被列为贡品荔枝与龙眼系喜温性水果,库区栽培间冻害发生,成为限制扩大栽培的主要因素,故多分布于万县－重庆江段两海拔２００ｍ上下地段,水库蓄水后,原栽培区部分被淹没,但水体有增温作用,为扩大栽培提供了有利的条件。研究了万县－重庆沿江两岸河谷地段与非河谷地段适宜载种范围     

长江流域粮食生产态势与潜力

通过大量的资料分析了长江流域在进入９０年代后的粮食生产的消费态势。粮食生产过程中存在的主要问题,及其对讹诈 影响,资料分析表明,长流域七省一市的粮食生产表现为,粮食单产略有提高,粮食总产徘徊,粮食消费量与居民的经济收入密切相关。     

大庆地区空气中总烃与非甲烷烃分布规律研究

分析了大庆地区空气中总径与非甲烷烃的比例关系，年、季、日变化规律及浓度水平。说明了总径与非甲烷径浓度水平在采暖期和非采暖期无显著差别，且冬、夏分布大体一致，高浓度多集中于大庆市东北部，浓度值向西南偏南方向递减，总烃总体浓度冬季较夏季偏向于西南这一规律。讨论了气候条件对分布规律的影响，并指出总烂的主要来源是油田开发和机动车尾气排放。