Optimization of reinforced soil embankments by genetic algorithm

A Genetic Algorithm (GA) is described, which produces solutions to the cost optimization problem of reinforcement layout for reinforced soil slopes. These solutions incorporate different types of reinforcement within a single slope. The GA described is implemented with the aim of optimizing the cost of materials for the preliminary layout of reinforced soil embankments. The slope design method chosen is the U.K. Department of Transport HA 68/94 ‘Design Methods for the Reinforcement of Highway Slopes by Reinforced Soil and Soil Nailing Techniques’. The results confirm that there is a role for the GA in optimization of reinforced soil design. Copyright © 2000 John Wiley & Sons, Ltd.     

使用VMware模拟双机HA环境及其应用前景

介绍使用虚拟计算机的概念和发展现状及VMware主要产品的区别,对于VMware的3个主要产品Work-station、GSX Server和ESX Server,给出了合理的使用建议,并论述了采用虚拟机所带来的好处以及在国家气象信息中心的应用前景。该文还介绍了VMware GSX Server的使用方法和注意事项。最后通过逐步的讲解,实现了一个虚拟的Suse Linux双机加共享存储阵列的高可用测试(HA)环境,以替代现实中昂贵的硬件环境。     

气象区域站数据全流程监控系统的设计和实现

气象区域站数据是防灾减灾服务开展的重要核心数据,实时性非常强,但由于传输环节多、监控不连续,之前主要依靠接收资料数量来反推传输情况,在业务实际应用中存在故障无法准确定位、监控精密度不细致、追查环节复杂等问题。该文通过引入工作流的方法,梳理区域站数据采集和应用的全工作流程,搭建了Zabbix集群监控系统,开展工作流程和监控脚本设计,从而实现对复杂故障和关键环节的监控,为区域站数据全流程监控提供一种解决方案。系统在业务运行中取得非常好的应用效果,使数据监控精准,数据传输和服务更加高效。     

1972年8月事件期间四个耀斑引起的日球层扰动的模拟研究

1972年8月发生的太阳耀斑事件是第20太阳周期内最重大的事件,我们在改进Hakamada-Akasofu方法（以下简称HA方法）的基础上,对事件期间四个较大的耀斑所引起的行星际扰动进行了计算机模拟研究,并取得了令人满意的结果。这些模拟包括赤道平面上一系列二维的激波形状、激波传播以及空间飞船先驱者9号、先驱者10号（以下简称P9、P10）和地球位置上的粒子速度-时间曲线。最后,本文还将该模拟结果与Dryer等人所做的同一事件的一维MHD模拟结果做了比较,并对模拟结果和HA方法本身做了一些讨论。     

我国水平地带性土壤中有机质的空间变化特征

主要根据全国第二次土壤普查的成果，对我国水平地带性土壤中有机质的含量和胡敏酸与富里酸比值的空间变化特征进行了概括，进而探讨了在不同自然和人因素影响下，土壤有机质的累积状况与稳定性特征。     

服务器集群技术的介绍与应用

服务器集群是一种比较新的技术,采用集群技术可以对硬件资源和应用程序提供高可用性、可扩展性和可管理性.本文阐述了服务器集群的概念、优点和几种常见的服务器集群类型,并介绍了集群技术在现有省级通信系统的实际应用和发展.     

Effects of pH and Ca competition on complexation of cadmium by fulvic acids and by natural organic ligands from a river and a lake

The technique of competitive ligand-exchange/anodic stripping voltammetry (CLE-SV) was used to investigate effects of pH and Ca concentration on cadmium complexation by fulvic acid (FA), as well as Cd speciation in two different freshwaters, a hardwater Lake Greifen and a softwater River Wyre. Binding of Cd to Suwannee river FA (10 mg/l) was determined at different pH (7–8.5) and in the presence of various concentration of Ca²⁺ (0–2 mmol/l). The results from one-ligand discrete models were compared to simulations by the WHAM VI model. In Lake Greifen, the determined dissolved [Cd²⁺] ranged from 10⁻¹³ to 10⁻¹² mol/l, and the conditional stability constant with natural ligands was log K _CdL about 9.5–10.5 (pH 8.6–8.8) with ligand concentrations of 1.2–7.8 × 10⁻⁶ mol/g C. In the softwater River Wyre, dissolved [Cd²⁺] ranged from 4 × 10⁻¹² to 1 × 10⁻¹¹ mol/l, and the ligands were weaker (log K _CdL 8.9–9.8, pH 8.0) with lower ligand concentrations (0.9–2.3 × 10⁻⁶ mol/g C). The titration curves of FA samples were close to the simulated curves by the WHAM VI model at pH 8.0–8.5, but deviated more from the model at lower pH, indicating that the results determined with CLE-SV for Cd-FA complexation are relevant to the data base in the model. Calculation of the Ca competition for Cd binding by FA showed a competition effect of similar strength as the measured one, but indicated a systematic difference between measured and modeled data at pH 7.5. Using the WHAM model for comparison with FA, the complexation of Cd by the River Wyre ligands was close to that of FA, whereas stronger complexation was observed in the Lake Greifen water. These differences may originate from different ligand composition in the lake and the river.     

1972年8月事件期间四个耀斑引起的日球层扰动的模拟研究

1972年8月发生的太阳耀斑事件是第20太阳周期内最重大的事件,我们在改进Hakamada-Akasofu方法（以下简称HA方法）的基础上,对事件期间四个较大的耀斑所引起的行星际扰动进行了计算机模拟研究,并取得了令人满意的结果。这些模拟包括赤道平面上一系列二维的激波形状、激波传播以及空间飞船先驱者9号、先驱者10号（以下简称P9、P10）和地球位置上的粒子速度-时间曲线。最后,本文还将该模拟结果与Dryer等人所做的同一事件的一维MHD模拟结果做了比较,并对模拟结果和HA方法本身做了一些讨论。     

Analysis of the influence of free ammonia on the accumulation of nitrite in the nitrite nitrification system

Low- and high-concentration nitric wastewater can induce stable nitrite accumulation and realize the nitrification system, with the nitrite accumulation rate between 50% and 90%. In the low-concentration nitrite nitrification system, the average FA concentrations during the period of stable nitrite accumulation remained at 7 to 10 mg/L. In the high-concentration nitrite nitrification system, the nitrogen oxidation activity will not be affected by biomass, the nitrite oxidation activity is related to the system biomass, it is recommended to be measured by FA/MLSS. Keeping the FA sludge load below 0.1 is the precondition of making good nitrite accumulation and nitrogen degradation rate. Nitrite oxidation bacteria cannot be totally eliminated or washed out from the system.     

Photochemical activity and characterization of the complex of humic acids with iron(III)

This study examined the effects of humic acids (HA) and Fe(III)–HA complex on the photodegradation of atrazine, one of the most widely used herbicides. It was shown that the photolysis of atrazine proceeded via first-order reaction kinetics and that atrazine photodegradation was inhibited by the presence of HA, whereas the rate for atrazine photolysis was promoted in solutions containing both HA and Fe(III). Interactions of Fe(III) with HA were characterized by SEM, EDX, UV–Vis and FTIR, revealing that Fe(III)–HA complex was formed by ligand exchange between oxygen groups of HA and Fe(III). Using fluorescence spectrometry the stability constant (K_c) and the fraction of fluorophores available for complexation (f) were obtained as log K_c = 4.28 and f = 74%. Photoformed Fe(II) by ligand-to-metal charge-transfer (LMCT) within the Fe(III)–HA complex was the most important factor involved in photolysis of atrazine, since Fe(II) was the reactant to generate hydroxyl radical. Thus, the rate of atrazine photodegradation in natural sunlit waters is dependent on both the amount of iron present and the interaction between HA and iron.