商用车铝合金油箱外观氧化问题分析及对策

随着商用车领域轻量化需求日益提升,商用车轻量化产品不断升级,外观好、质量轻、加工性优良的铝合金油箱逐渐取代铁质油箱。本文针对铝合金油箱喷塑工艺后的表面氧化问题,通过对喷涂工艺试验验证、外观质量和理化分析等手段,判定失效主要原因为腐蚀性元素Cl的引入、5052铝合金中的铁杂质含量较高。经对喷涂后工艺优化,减少腐蚀性元素Cl的引入及控制5052铝合金中的铁杂质含量,有效解决了油箱外观氧化问题。

SMD器件翼型引脚氧化问题的研究与解决

SMD器件高密度封装翼型引脚,在某种原因下引脚产生氧化,对SMD器件的可焊性以及焊接质量造成影响。为了更好地分析并解决此类问题,对在特定情况下,使用非常规性的处理,去除引脚氧化的工艺方法进行了详细阐述,并介绍了焊接后焊点检查和试验验证的情况。在此基础上,通过TSOP芯片的具体案例,详细描述了工艺流程和操作技巧,为解决SMD器件高密度封装翼型引脚氧化问题提供解决方案,供业界同行参考。

低合金钢不锈钢压力管道X射线检测中不可忽视的氧化问题

1 前言随着现代工业技术的发展,产品质量的进一步提高,各行业对输送流体介质的压力管道要求也随之提高。特别在轻工业、生物制药业尤为突出。然而,因压力管道在使用过程中所处的特殊性以及所发生的安全事故情况,国家已将压力管道纳入强制检验的范畴。并出台和制定了相关的法规、规程、检验标准。就上述两行业而言,低合金钢、不锈钢将是输送流体介质的主要压力管道。

抓基础 快解题——2006年全国各省市高考化学试题中的氧化还原问题之解决方略

氧化还原反应是中学化学重要的基本概念之一，也是历年化学高考热点之一。在2006年全国各省市高考化学试题中，氧化还原反应问题被多次考查，下面举例加以探讨。

热点问题不回避，狠抓基础快解题——2005年江苏高考化学试题中的氧化还原问题之解决方略

氧化还原反应是中学化学重要的基本概念之一，也是历年化学高考热点之一．在2005年江苏高考化学试卷中，氧化还原反应问题被多次考查，下面我们不妨逐一加以探讨。

抗氧化剂在猪饲料中的应用

猪饲料中的油脂或脂溶性维生素、胡萝卜素及类胡萝卜素等物质,易被空气中的氧氧化、破坏,使饲料营养价值下降、适口性变差,甚至导致饲料酸败变质,所形成的过氧化物对动物具有毒害作用。在猪饲料中添加一定的抗氧化剂,可延缓或防止饲料中物质的自动氧化作用,是解决饲料在生产、运输和储存过程中被氧化问题的有效方法。

Modified Self-adaptive Immune Genetic Algorithm for Optimization of Combustion Side Reaction of p-Xylene Oxidation

In recent years, immune genetic algorithm (IGA) is gaining popularity for finding the optimal solution for non-linear optimization problems in many engineering applications. However, IGA with deterministic mutation factor suffers from the problem of premature convergence. In this study, a modified self-adaptive immune genetic algorithm (MSIGA) with two memory bases, in which immune concepts are applied to determine the mutation parameters, is proposed to improve the searching ability of the algorithm and maintain population diversity. Performance comparisons with other well-known population-based iterative algorithms show that the proposed method converges quickly to the global optimum and overcomes premature problem. This algorithm is applied to optimize a feed forward neural network to measure the content of products in the combustion side reaction of p-xylene oxidation, and satisfactory results are obtained.

Multi-objective optimization of p-xylene oxidation process using an improved self-adaptive differential evolution algorithm

The rise in the use of global polyester fiber contributed to strong demand of the Terephthalic acid （TPA）. The liquid-phase catalytic oxidation of p-xylene （PX） to TPA is regarded as a critical and efficient chemical process in industry [ 1 ]. PX oxidation reaction involves many complex side reactions, among which acetic acid combustion and PX combustion are the most important. As the target product of this oxidation process, the quality and yield of TPA are of great concern. However, the improvement of the qualified product yield can bring about the high energy consumption, which means that the economic objectives of this process cannot be achieved simulta- neously because the two objectives are in conflict with each other. In this paper, an improved self-adaptive multi-objective differential evolution algorithm was proposed to handle the multi-objective optimization prob- lems. The immune concept is introduced to the self-adaptive multi-objective differential evolution algorithm （SADE） to strengthen the local search ability and optimization accuracy. The proposed algorithm is successfully tested on several benchmark test problems, and the performance measures such as convergence and divergence metrics are calculated. Subsequently, the multi-objective optimization of an industrial PX oxidation process is carried out using the proposed immune self-adaptive multi-objective differential evolution algorithm （ISADE）. Optimization results indicate that application oflSADE can greatly improve the yield of TPA with low combustion loss without degenerating TA quality.

Carbon Footprint across the Coffee Supply Chain： The Case of Costa Rican Coffee

The issue of carbon emissions has been on the corporate sustainability agenda for some years. For those working in agricultural supply chains, the challenges remain significant, given the diverse direct and indirect emissions occurring throughout the value chain. This study determines the carbon footprint of the supply chain of Costa Rican coffee exported to Europe, using best practice methodology to calculate greenhouse gas emissions. Overall, it was found that the total carbon footprint across the entire supply chain is 4.82 kg CO2e kgx green coffee. The carbon footprint of the processes in Costa Rica to produce l km of green coffee is 1.77 kg CO2e. The processes within Europe generate 3.05 kg CO2e kg-1 green coffee. This carbon footprint is considered as ＂very high intensity＂. This paper also identifies the sources of the most intense emission and discusses mitigation possibilities on which efforts must be focused.

Rapideye Images in the Study of Contaminated Areas： The Case of Niccioleta （Tuscansy-ltaly）

Mining activity in Italy has been one of the main productive activities for millennia, particularly in the Tuscany region which has a great mining tradition, unfortunately characterized in the past by a management little interest to environmental problems. The area under study is the disused mine Niccioleta, in Val d＇Aspra, located about 6 km NE of Massa Marittima in the province of Grosseto. The area is characterized by the presence of four major landfills, in which prevail quantitatively fine-grained materials resulting from the treatment by flotation of pyrite. The study of satellite images offers a new approach to the study of environmental problems. The results obtained from the RapidEye images showed the presence of pyrite and chalcopyrite followed from arsenopyrite, as confirmed by the analysis of diffractometer of the samples and by bibliographic data. RapidEye images lend themselves very to be used to monitor areas of disused mining deposits of ores with primary mineralization predominantly sulphides and subject to oxidized characterized by processes of oxidation/dissolution of pyrite sulphide most common and abundant. In fact, the results of this study have highlighted the potential of remote sensing applied to the study of mining areas, noting the possible benefits, both time and cost, which could be obtained by using these techniques.

Oxygen and nitrogen-doped metal-free carbon catalysts for hydrochlorination of acetylene

Activated carbon was tested as metal-free catalyst for hydrochlorination of acetylene in order to circumvent the problem of environment pollution caused by mercury and high cost by noble metals. Oxygen-doped and nitrogen-doped activated carbons were prepared and characterized by XPS, TPD and N2 physisorption methods. The influences of the surface functional groups on the catalytic performance were discussed base on these results. Among all the samples tested, a nitrogen-doped sample, AC-n-US00, exhibited the best performance, the acety- lene conversion being 92% and vinyl chloride selectivity above 99% at 240 ~C and C2H2 hourly space velocity 30 h- 1. Moreover, the AC-n-US00 catalyst exhibited a stable performance during a 200 h test with a conversion of acetylene higher than 76% at 210 ~C at a C2H2 hourly space velocity 50 h 1. In contrary, oxygen-doped catalyst had lower catalytic activities. A linear relationship between the amount of pyrrolic-N and quaternary-N species and the catalytic activity was observed, indicating that these nitrogen-doped species might be the active sites and the key in tuning the catalytic performance. It is also found that the introduction of nitrogen species into the sample could significantly increase the adsorption amount of acetylene. The deactivation of nitrogen- doped activated carbon might be caused by the decrease of the accessibility to or the total amount of active sites.

Planning Strategic Sustainable Development in Malaysia by Incorporating the Concept of Low Carbon Society

Malaysia has undergone rapid urbanization and economic growth for past decades and is expected to continue to have an average economic grow at 5%-6% per annum in the next five years. This phenomenon of growth and pursuit of socio-economic progress has great impact not only on the economy but also on community life style and environment. The concept of sustainable development was adopted by Malaysia government as early as mid 1990s to address some of the emerging environmental issues and more specifically on climate change issues recently. Malaysia government announced a commitment of voluntary 40% reduction in CO2 emission intensity by 2020 during the Conference of Party （COP15） meeting in Copenhagen in 2009. In parallel to this commitment of CO2 emission reduction, the concept of sustainable development in urban planning should incorporate a more comprehensive and quantitative approach in the preparation of development plan as well as in exercising the routine development control practice at the local planning authority. This paper prepares a quantitative scenario study on the establishment of low carbon society in Iskandar Malaysia.

肌肤美白年轻的秘密:抗糖化

这个春天,留下你最美的倩影盼望着盼望着,春的脚步近了,树叶都变绿了,花儿都开好了,就等我们一起去踏春赏春。在这样的春色美景中,你一定想多拍几张照片留下美好纪念。想要在这个春天留下最完美的照片,只减肥瘦身是不够了,还得从头到脚大变身。首先是皮肤。想要有美白年轻的肌肤状态,只是做抗氧化工作是不够的,还要抗糖化;其次是妆容。

Kinetics of FeSe_2 oxidation by ferric iron and its reactivity compared with FeS_2

The mobility and bioavailability of selenium is a major health and environmental issue and a main concern for geological disposal of high-level radioactive waste. Chemically and/or microbially mediated oxidation of insoluble Se-bearing particulate, such as iron selenides, to dissolved and mobile phases controls the transport and distribution of Se in the environment. The oxidation of ferroselite （FeSe2） by ferric iron was investigated in anoxic conditions. The redox reaction can be represented by： FeSe2 ＋ 2Fe3＋ = 2Se^0 ＋ 3Fe2＋. Kinetic studies indicated that the reaction can be described by second-order rate law, with rate constants of 0.49±0.01, 0.85±0.02, 1.84±0.04, and 3.29±0.13 L mol^-1 s^-1 at pH 1.62, 1.87, 2.23, and 2.49, respectively. The positive correlation between reaction rate and pH implies that diffusion of Fe3＋ oxidant to the mineral surface is the rate-determining step. The strong reactivity of FeSe2 towards Fe^3＋ suggests that ferric iron may play a significant role in FeSe2 oxidation process （e.g., by Se^4＋, 02, etc.） and Se^0 should be the first reaction product. Also, it was shown that the reduction rate of Fe^3＋ or Se^4＋ by pyrite （FeS2） can be significantly increased in the presence of FeSe2, suggesting a stronger reactivity of FeSe2 compared with pyrite. The results obtained extend our knowledge about the subtle interaction between Se, pyrite and iron selenides in the environment, and give insight into the transfer of selenium from iron selenides to bio-available selenium （i.e., selenite and selenate） in the Se-rich environment.

The dual role of hydrogen peroxide in fuel cells

Clean and highly efficient energy production has long been sought after, as a way to solve global energy and environmental problems. Fuel cells, which convert the chemical energy stored in fuel directly into electricity, are expected to be a key enabling technology for the pressing energy issues that plague our planet. Fuel cells require oxygen as an oxidant and require oxygen tank containers when used in air-free environments such as outer space and underwater. Hydrogen peroxide has been extensively uti- lized as an alternative liquid oxidant in place of gaseous oxygen. In addition to being an oxidant, hydrogen peroxide can donate electrons in the oxidation reaction to act as a fuel. This article provides an overview of the dual role of hydrogen peroxide in fuel-cell applications, including working principle, system design, and cell performance. Recent innovations and future perspectives of fuel cells that use hydrogen peroxide are particularly emphasized.