Parametric models of local search progression

Algorithms that search for good solutions to optimization problems present a trace of current best objective values over time. We describe an empirical study of parametric models of this progression that are both interesting as ways to characterize the search progression compactly and useful as means of predicting search behavior. In our computational experiments, we give examples of a variety of problems and algorithms where we are able to use the parametric models to make predictions of performance that cross instances and instance sizes.     

大型剧院火灾自动报警系统设计

结合大型剧院火灾自动报警系统工程设计实例,分析、比较剧院入口大厅、观众厅及舞台区域高大空间火灾探测器的选择,阐述在高大开放式空间建筑中怎样合理地选择火灾探测器。     

Pollutant concentrations and fluxes in both stormwater and wastewater at the outlet of two urban watersheds in Nantes (France)

A two-year study of pollutants in both the stormwater and wastewater of urban watersheds has been conducted in Nantes (France). The present paper discusses the characteristics of pollutants transported by stormwater and wastewater collection networks in two urban watersheds. A physicochemical characterisation of the effluents was performed, along with an estimation of pollutant fluxes discharged into the Gohards River. Suspended solids (SS), trace metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides were studied. SS, Zn, Cu and glyphosate were the main pollutants in stormwater and wastewater. In the watersheds examined, the pyrolitic origin of PAHs (mainly from traffic) was determined through ratios, with fluoranthene and pyrene being predominant. Despite a reduction in the use of pesticides in Nantes Metropolitan area, herbicides containing glyphosate were still detected in stormwater. It should be noted that this herbicide is widely used by homeowners, a fact that may explain its occurrence in stormwater.     

湿法消化-氢化物原子荧光法测定植物提取物中镉的含量

探讨了应用原子荧光光法测定植物提取物中镉含量的方法。样品用硝酸+高氯酸混合液消化,在盐酸介质中,试样中的镉在镉专用2号试剂存在下,镉1号专用还原剂将二价镉还原成镉的挥发性组分,用AFS-8230原子荧光光度计测定。该法线性范围为0~60μg/L,相关系数r=0.9998,检出限为0.0024μg/L,相对标准偏差为1.36%,回收率为92.8%~96.1%。     

Coupling of electrodialysis and leaching processes for removing of cadmium from phosphate ore

Phosphate rock is a valuable material that is used for the production of large phosphorus chemicals. However, this natural material usually contains some toxic elements such as cadmium (Cd). Cd is a non-nutritive metal regarded as harmful to both humans and the environment. The main toxic effects of Cd on human health are the kidney and renal cortex diseases. Other effects were observed on pulmonary, cardiovascular, and musculoskeletal systems, in addition to including Cd as a human carcinogen. In order to reduce the cadmium content in the phosphate ore, an original method was studied and consists of coupling both leaching and electrodialysis. The effects of process parameters, such as reaction time, nature, and concentration of the extracting agent, liquid/phosphate ore ratio, pH, temperature, and current density, were investigated. The obtained results show that the cadmium extraction from phosphate ore using simple batch leaching does not reduce the cadmium content to the required level. However, the application of leaching- electrodialysis coupled method at optimum current density of 10 mA cm^?2 increases the cadmium extraction efficiency up to 84.3%. This synergetic process could be applied to the treatment of phosphate ore containing cadmium.     

基于热示踪法的井下流量测量系统设计

根据热示踪方法的流量测量原理,采用C8051F360单片机、热源发生器及温度传感阵列等器件,设计一种基于热示踪方法的井下流量测量系统。该系统利用热源发生器对井下流体加热,当加热的流体经过传感器阵列时即可根据热示踪方法测出油水两相流的流量,并将数据传输给由LabVIEW设计的井上上位机系统,实现了井上地面计量站对井下数据的实时监控,解决了井下流量测量难、实时监测难、数据量大的问题。     

Synthesis,characterisation of ternary layered double hydroxides (LDH) for sorption kinetics and thermodynamics of Cd2+

Kinetic and thermodynamic studies were carried out on the sorption of Cd²⁺ on three synthesised and characterised layered double hydroxides, namely: Ni-Co-Ti, Ni-Co-La and Mn-Ni-Al-CO₃. Sorption kinetics were investigated through time-dependent studies. Thermodynamics were determined by the effect of temperature on adsorption. Kinetic modelling of the adsorption of Cd(II) ions on the LDHs was determined using the first-order, pseudo-first order, pseudo-second order and Elovich kinetic models, as well as additional diffusion models. The results showed that the pseudo-second-order model best correlated the adsorption data with R² values of 1.000, 0.998 and 1.000 for NiCoTi, NiCoLa and MnNiAl-LDH respectively. Diffusion of the adsorbate was best correlated by the Weber-Morris intraparticle diffusion model with R² values of 0.9753, 0.8472 and 0.9412 for NiCoTi, NiCoLa and MnNiAl-LDH respectively. Thermodynamic studies showed that the adsorption was spontaneous and exothermic with a high probability of sticking.     

乙内酰脲体系无氰电镀镉工艺

目的开发一种新型的无氰镀镉工艺,替代传统的氰化镀镉。方法以海因和柠檬酸为主、辅络合剂,通过选用光亮剂和表面活性剂获得无氰镀镉工艺配方,优化pH值、电流密度和温度等工艺参数。按规定的方法测试镀液的分散能力、深镀能力。利用SEM、三维显微镜观察镀层的微观形貌,通过极化曲线和循环伏安曲线讨论镀液的极化度和成膜机理,利用塔尔菲尔曲线和点滴实验测试其耐蚀性。结果镉电沉积是通过"成核/生长"机理进行的,乙内酰脲体系无氰镀镉双络合剂协同作用明显,镀液极化能力强。与氰化镀镉相比,该工艺电流效率提高20%,沉积速率提高30%,分散能力可达89%以上,镀液深镀能力和镀层结合力检验合格,镀层表面光亮细致,钝化膜彩虹色明显。无氰镀镉层耐蚀性优于氰化镀镉层,与氰化镀镉钝化层相比,钝化封闭后,自腐蚀电流密度降低至之前的1/15,耐蚀性显著提高。结论该配方及工艺条件为:硫酸镉30～50 g/L,硫酸钠60～100 g/L,乙内酰脲60～70 g/L,柠檬酸20～40 g/L,光亮剂1～3 g/L,表面活性剂1～3g/L,pH=5～6,温度15～35℃。镀液镀层各项性能优越,完全可以替代氰化镀镉工艺用于我国飞机和航空发动机钢结构的防护。     

城市景观复写——从空间分析到设计途径

当代景观设计中价值取向的转变,包括设计行为从创造画面转向塑造场所,从创造新事物转向重现场地本质与原貌。依据景观设计中的空间特征和规划设计应用价值,将文本视角下的当代景观空间特征“复写”（palimpsest）定义为场地中各历史层次与当代层次的结合与共同显现。复写空间利用场地的潜力,实现了景观意义的传达,具有二元性、互文性及透明性的特点。复写既可以作为分析工具,也可以作为设计手段,其核心价值在于：多层空间结构得以平等呈现;历史信息积累而显现场地特质;设计创造诱发新的发展空间与场地产生关联。结合案例论述,研究与复写相关的分析方法与设计路径：呈现自治或在场地介入过程中建立互设关系,相关设计思想可回溯到埃森曼“人工开挖”（artificial excavation）的设计理念,以及文化景观及遗产保护中的“踪迹”（trace）概念。以场地空间特征出发,选择合适的设计方法,进而提出复写空间的多层建构是设计过程的关键部分。