大型展馆项目综合展位箱设计要点及布置方案

本文结合两个大型展馆项目设计实例,对大型展馆的综合展位箱设计要点及布置方案进行了较全面的归纳总结和分析论述,旨在对展馆设计起到借鉴作用。     

Sedimentary records of sewage pollution using faecal markers in contrasting peri-urban shallow lakes

Sewage contamination in shallow lake sediments is of concern because the pathogens, organic matter and nutrients contribute to the deterioration of the water-bodies' health and ecology. Sediment cores from three shallow lakes (Coneries, Church and Clifton Ponds) within Attenborough nature reserve located downstream of sewage treatment works were analysed for TOC, C/N, δ¹³C, δ¹⁵N, bacterial coliforms and faecal sterols. ²¹⁰Pb and ¹³⁷Cs activities were used to date the sediments. Elemental analysis suggests that the source of organic matter was algal and down profile changes in δ¹³C indicate a possible decrease in productivity with time which could be due to improvements in sewage treatment. δ¹⁵N for Coneries Pond are slightly higher than those observed in Church or Clifton and are consistent with a sewage-derived nitrate source which has been diluted by non-sewage sources of N. The similarity in δ¹⁵N values (+ 12‰ to + 10‰) indicates that the three ponds were not entirely hydrologically isolated. Analysis by gas chromatography/mass spectrometry (GC/MS) reveals that Coneries Pond had sterol concentrations in the range 20 to 30 μg/g (dry wt.), whereas, those from Clifton and Church Ponds were lower. The highest concentrations of the human-sourced sewage marker 5β-coprostanol were observed in the top 40 cm of Coneries Pond with values up to 2.2 μg/g. In contrast, Church and Clifton Pond sediments contain only trace amounts throughout. Down-profile comparison of 5β-coprostanol/cholesterol, 5β-coprostanol/(5β-coprostanol + 5α-cholestanol) and 5β-epicoprostanol/coprostanol as well as 5α-cholestanol/cholesterol suggests that Coneries Pond has received appreciable amounts of faecal contamination. Examination of 5β-stigmastanol (marker for herbivorous/ruminant animals) down core concentrations suggests a recent decrease in manure slurry input to Coneries Pond. The greater concentration of β-sitosterol in sediments from Church and Clifton Ponds as compared to Coneries is attributed in part to their greater diversity and extent of aquatic plants and avian faeces.     

Characterization of copper bioreduction and biosorption by a highly copper resistant bacterium isolated from copper-contaminated vineyard soil

Copper is an essential but toxic heavy metal that negatively impacts living systems at high concentration. This study presents factors affecting copper bioremoval (bioreduction and biosorption) by a highly copper resistant monoculture of Pseudomonas sp. NA and copper bioremoval from soil. Seven bacteria resistant to high concentration of Cu(II) were isolated from enrichment cultures of vineyard soils and mining wastes. Culture parameters influencing copper bioreduction and biosorption by one monoculture isolate were studied. The isolate was identified by 16S rRNA gene sequence analysis as a Pseudomonas sp. NA (98% similarity to Pseudomonas putida, Pseudomonas plecoglossicida and other Pseudomonas sp.). The optimal temperature for growth was 30 °C and bioremoval of Cu(II) was maximal at 35 °C. Considerable growth of the isolate was observed between pH 5.0 and 8.0 with the highest growth and biosorption recorded at pH 6.0. Maximal bioreduction was observed at pH 5.0. Cu(II) bioremoval was directly proportional to Cu(II) concentration in media. Pseudomonas sp. NA removed more than 110 mg L^− 1 Cu(II) in water within 24 h through bioreduction and biosorption at initial concentration of 300 mg L^− 1. In cultures amended with 100 mg L^− 1, 20.7 mg L^− 1 of Cu(II) was biologically reduced and more than 23 mg L^− 1 of Cu(II) was biologically removed in 12 h. The isolate strongly promoted copper bioleaching in soil. Results indicate that Pseudomonas sp. NA has good potential as an agent for removing copper from water and soil.     

厚铜板线路制作工艺探讨

在厚铜板件的生产制作过程中,蚀刻一直是一个难点。为了达到蚀刻目的,制作上一般选择多次快速蚀刻或者一次性慢速蚀刻。本文通过对比不同面铜厚度的板进行蚀刻,分析比较不同蚀刻方式对蚀刻因子、线宽和线形的影响,并对其差异性进行原因分析。为生产和设计提供有价值的参考。     

一种用于导电油墨的特种铜粉制备研究

特种导电油墨是全印制电路技术开发与应用的关键之一。本文报道了利用硫酸铜、碳酸钠、抗坏血酸等为原料,通过固相反应获得纳米非球形铜粉方法。通过SEM、EDS分析表明,获得的产物为一种柱状的高纯铜粉,直径大约500nm,可以作为全印制电路技术用高性能特种油墨的开发。     

Controlled synthesis of copper nano/microstructures using ascorbic acid in aqueous CTAB solution

This paper describes a low-temperature green chemical synthesis of various morphologies of copper nano/microstructures. These syntheses achieved high yields in aqueous solution using ascorbic acid as a reductant and the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a capping agent. The resulting copper particles were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and UV-Vis. absorption spectroscopy techniques. From the SEM analysis, it was found that different morphologies of copper particles, including submicron polyhedrons, micrometer rods, spherical nanoparticles, and nanowires were obtained by varying factors such as the molar ratio of reactants (ascorbic acid and CuSO₄·5H₂O), pH, reaction time, and temperature. Increasing the molar ratio of ascorbic acid to precursor salt and increasing the pH led to a decrease in the size of copper particles formed. At short reaction times, spherical copper nanoparticles with an average diameter of 90 nm are obtained. When the reaction time was prolonged, the nanoparticles transformed into nanowires with diameters in the range of 100-250 nm, and lengths of up to 6-8 μm. When the reaction temperature was decreased, Cu mixed with Cu₂O particles were obtained instead of Cu particles. The resultant copper particles were confirmed by EDX and XRD to be pure Cu, with face-centred cubic (fcc) structures.     

硫铁矿烧渣酸浸铜反应动力学研究

研究了硫酸烧渣的硫酸浸铜过程中,搅拌速率、浸出剂初始质量浓度、固液比、浸出温度和矿物粒径对浸出率的影响,并对硫铁矿烧渣浸取铜过程动力学进行了分析。研究结果表明,该浸出过程符合收缩芯模型,与化学反应控制动力学方程式相吻合,浸出反应的表观活化能为39.19 kJ/mol,浸出过程控制步骤为化学反应控制。     

汽轮机叶片的盐垢处理及预防

针对丰喜肥业(集团)有限公司10万t/a甲醇项目空分装置中汽轮机叶片结垢现象,分析了原因,通过采取降低汽轮机负荷等方法,并进行清洗,使汽轮机工况恢复正常。同时,制定出相关的预防措施,以维护汽轮机的正常运行。     

产水气井结盐垢机理研究及防治

文23气田产高矿化度CaCl2水型地层水,气井开发至井底压力小于7MPa时,井底开始结盐垢,盐垢的成分主要是NaCl,其次是少量CaSO4和CaCO3钙垢。气井压力降低使天然气饱和水蒸汽含量增加,地层水产生蒸浓反应成为过饱和溶液,盐垢结晶析出沉淀形成气井结盐。气井井筒结盐垢部位一般集结在井底油管内外壁、套管内壁,形成一个结盐垢初始点和终止点的分布状态。清除井筒氯化物垢的有效方法是用淡水溶解清洗,清除井筒和井底的钙垢盐类要用化学反应法和机械破碎法。     

高频馈源喇叭密封罩工艺性能研究

主要介绍了某馈源喇叭特殊的气密性要求及在高频环境下对密封罩的电性能要求,选择使用两面覆铜的高频微波基板作为馈源喇叭的密封罩材料,采用焊接的密封连接方式.并分别从密封罩的结构构成、材料成分、电性能特点、可加工性及焊接强度等方面阐述了此种高频微波基板的经济性和可靠性,完全满足馈源喇叭气密性及透波性性能指标要求.