理想弹塑性材料弯曲回弹分析及回弹弯矩计算

分析了弯曲回弹应力应变变化过程 ,推导了矩形截面杆回弹弯矩、回弹曲率的计算公式 (1 4 )、(1 1 ) ;发现经典纯弯曲理论确定回弹弯矩的方法与公式 (1 4 )比较存在较大理论误差     

A methodology for the life cycle and sustainability analysis of manufacturing processes

Life cycle assessment is emerging as a powerful tool in the evaluation of the environmental impact of manufacturing processes. This paper describes a general methodology for the life cycle analysis of manufacturing processes taking into account the flexibility and decision-making potential of knowledge base systems. Emphasis is placed on on-site waste minimisation and associated sustainability characteristics in relation to environmental impact assessment and process improvement. The ensuing software model is applied with some success to an initial study of pulp and paper manufacture.     

海洋碳的源与汇

通过对海洋碳源汇最近研究成果的分析,剖析了海洋碳源汇的内涵,提出了“表观碳源汇”与“实际碳源汇”的概念,对海洋碳源汇不确定性的原因进行分析,提出碳参数测定不淮确与其关键生物地球化学过程不清楚是其根本原因,继而提出了海洋碳源汇研究应特别注重陆架边缘海碳循环过程研究,提高碳参数测定的淮确性和应深入研究控制碳循环关键的海洋生物地球化学过程是其研究关键。     

Separating method and dynamic processes of Nano-Al13

In order to investigate the characteristics of pure Nano-Al₁₃, Nano-Al₁₃ was separated and purified from a series of poly-aluminum chloride (PAC) solutions which had the same Al₁₃ percentage but different total Al concentrations, by using column chromatography, ethanol-acetone resolving and SO²⁻ ₄/Ba²⁺ displacement. The Al₁₃ species yield was characterized by Al-ferron timed complexation spectrophotometry and ²⁷Al-NMR (nuclear magnetic resonance). The coagulation efficiency of Nano-Al₁₃, PAC and AlCl₃ in synthetic water was also investigated by Jar tests. The dynamic process and aggregation state of kaolin suspensions coagulating with Nano-Al₁₃, PAC and AlCl₃ were similarly investigated using a photometric dispersion analyzer 2000 (PDA2000). The experimental results indicated that the ethanol-acetone resolving method was simple and could separate the PAC solution at different concentrations, while column chromatography could separate PAC solutions at low concentrations. The SO₄ ²⁻/Ba²⁺ displacement method could separate PAC solutions at high concentrations. However, extra inorganic cation and anion could be added in the solution during separation. The coagulation efficiency and dynamic experimental results showed that Nano-Al₁₃ with high positive-charged species was effective in removing turbidity and color. The dynamic process results showed that Nano-Al₁₃ also had the best recovery capability after shearing compared with PAC and AlCl₃ because the Nano-Al₁₃ conformation is more effective in charge neutralization. Translated from Acta Scientiae Circumstantiae, 2005, 25(6): 767–772 [译自: 环境科学学报]     

转向锤臂锻件工艺与模具设计的改进

通过对转向锤臂锻件结构与工艺的改进 ,改变了该锻件的锻模结构 ,提高了该锻件的模锻工艺性和经济效益。     

Development and application of innovative technologies for drinking water quality assurance in China

The continuously deteriorating quality of source water is threatening the safety of drinking water in China. Various efforts have been made to update water treatment processes to decrease the pollution problems of drinking water, such as protection of drinking water sources, enhancement of conventional treatment processes, and development of new or advanced treatment technologies. This paper reviews a variety of protection and remediation methods for drinking water sources, development and application of drinking water treatment technologies, new technologies for special pollutants removal from groundwater, and the latest research progress on water distribution systems in China.     

水厂常规净化工艺生物处理化可行性的探讨

水厂常规净化处理工艺,存在不能有效地去除有机污染物,以及易生成致突变物的严重缺陷。因此,一般要增加臭氧一生物活性炭设施以处理被污染的原水。本文在分析试验数据的基础上,提出原水经生物塔滤预处理后,再经生物处理设施改造过的常规处理设备处理,最后通过生物活性炭滤池过滤并加氯消毒。即可实现水厂常规净水工艺的生物处理化,将是一种合理而可行的处理系统。     

汽车翼子板零件的成形与工艺分析

通过对汽车翼子板零件投料冲压试验,对零件进行了应变测试分析,评价试验钢板的成形效果,分析了冲压工艺、表面粗糙度和板厚等条件对零件冲压生产的影响,得到翼子板零件的最佳用材方案及冲压工艺条件。     

Present status of aerosol research in China

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中国农业土壤N_2O排放量估算

采用针对农业土壤痕量气体排放估算开发的、基于N2 O的产生、传输和消耗机理的反硝化分解模型 (DNDC模型 ) ,在建立的有关中国气候、农业土壤和农业生产的分县数据库基础上 ,估计了我国目前农业土壤N2 O的排放量 ,并分析了气候变化和农业耕作措施对全国N2 O排放的影响 .结果表明 ,中国农田土壤的N2 O排放总量为 0 31(0 18— 0 44 )Tg(N)·a - 1,化肥使用量的变化对N2 O排放量的影响最大 .