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1.
Alumina (Al2O3) coatings of different thickness were deposited on OT59 brass substrate (BS) using the metal organic chemical vapour deposition (MOCVD) technique to evaluate the corrosion performance by EIS measurements. The used precursor was dimethyl-aluminium-isopropoxide. Electrochemical characterizations of the deposited films were performed in a standard very aggressive acidic solution (aerated 1N H2SO4 at 25 °C up to 168 h of immersion time) by means of direct current method (Tafel curves) and electrochemical impedance spectroscopy (EIS). The Rutherford backscattering spectroscopy (RBS) indicated that the films are very pure with the correct Al2O3 stoichiometry, while the IR absorption spectra showed that the films did not contain any OH groups. The surface film morphology was investigated by atomic force microscopy (AFM) and displayed a globular texture. The films were very smooth, with a maximum root mean square roughness, for example, of 14 nm for a 0.96 μm thick coating. The EIS data confirmed, as expected, that a 2.40 μm Al2O3 layer ensures the best corrosion protection after 168 h of immersion in the very acidic environment used.  相似文献   
2.
开发了用O3氧化钝化多孔Si(PS)的实用工艺方法。O3的基本作用是对Si-Hx和Si悬挂键(DB)的充分氧化,经过随后158d贮存的老化实验,得到了表面Si—H,键完全被Si-O3膜和Si-烷基膜所替代并覆盖的PS,其光致发光(PL)强度达到稳定的增强,这归因于PS纳米晶粒的表面势垒高度的提高以及量子效率的提高。  相似文献   
3.
Abstract

The extraction of Eu(III) from aqueous HNO3 solution into a water‐in‐oil (W/O) microemulsion occurring in hexane was studied. Aerosol OT (AOT?) was used as an anionic surfactant, and a bulky diamide (DA), N,N ‐dioctyl‐N,N ‐dimethyl‐2‐(3‐oxapentadecyl)propane‐1,3‐diamide, was employed as an electrically neutral extractant. The combination of AOT? and the DA shows a very strong cooperative effect on the metal extraction. The microemulsion containing AOT? alone in hexane, equilibrated with the acidic solution, is unstable. However, in the presence of the electrically neutral extractant acting as a “masking” ligand to H+, the microemulsion in the hexane phase is dramatically stabilized, which enhances the distribution of Eu(III) to the organic phase. The distribution of the metal in the micellar extraction system is also greatly affected by the concentration of an electrolyte, such as HNO3 or NaNO3, playing two important roles, i.e., the formation of the microemulsion, “promoting” the metal extraction, and the ion‐exchange of the metal ion for the cation yielded from the electrolyte, contrarily, “suppressing” the metal extraction.  相似文献   
4.
A simple and convenient HPLC-FD detection method for ochratoxin A (OTA) with a high detection limit and a short run time has been developed. OTA has been found in most samples of Chinese market wine, including domestic and imported wines, but the content was not very high. Only a few wines showed an OTA content that exceeded the EC and OIV limits, indicating that most Chinese market wines were safe. The OTA intake for Chinese from wine was 0.017 ng/kg (bw) per day, which was lower than the SCF and JECFA limits and also lower than in many other countries. This was mainly due to the low per capita wine consumption in China, but it is still necessary for the Chinese government and wine makers to monitor OTA levels in wine and to establish relevant regulations. An egg white treatment (0.20 mg/mL, 48 h) was the best removal method for OTA.  相似文献   
5.
目前,操作员终端(OT)系统需要根据特定的站场图去开发特定的系统。为解决上述问题,根据OT系统的开发需求,本文介绍了一种可复用的OT系统站场图的实现方法。该方法基于XML技术和组件化程序思想,能有效的缩短了OT仿真系统的开发周期,简化开发过程。采用这种方法的操作员终端系统无需重新编译就可以自动适应不同的线路情况。  相似文献   
6.
探讨了城市智能管理运行架构、城市泛在感知设施、机器通信能力提升技术、数据共享和活化技术等关键技术。认为巨系统要形成良好的生态体系和自我成长机制,关键技术的突破和相关技术的综合运用都至关重要。关键技术的突破和相关技术的综合运用才能推动智慧城市建设的深入开展和演进。  相似文献   
7.
针对腐蚀产物的控制,对比3种给水处理方式及对给水加氧机理的分析,提出给水加氧处理是控制腐蚀产物的最佳方式,通过国内超(超)临界机组目前运行现状、给水处理方式及机理、氧化皮的形成与加氧的关系,探讨了1 000 MW超超临界机组给水加氧的可行性及风险。  相似文献   
8.
在区块链数据存储与查询过程中,由于区块链的透明性和公开性,全网所有用户均有可能获取查询者的数据信息,存在泄漏查询者隐私数据的风险。采用区块链链上-链下存储思想,设计区块链数据存储模型,引入代理重加密机制,将存储者加密后的数据分布式存储在链下,将存储者发送的索引信息和Merkle树根哈希值存储在链上,确保了数据的完整性、可靠性和可验证性,并减少了区块链数据对存储资源的占用。利用椭圆曲线加密算法设计区块链数据保密查询的不经意传输协议,使得全网所有用户均无法获取查询者的数据信息,保护了区块链数据传输过程中查询者的隐私。分析结果表明,该协议中查询者完成一次区块链上的不经意传输仅需2n+2k+2次椭圆曲线乘法运算,相比于现有不经意传输协议具有存储空间小、计算复杂度低等优势,并且在相同长度的密钥下具有更高的安全性。  相似文献   
9.
BackgroundMany studies around the world reported the occurrence of many mycotoxins and their metabolites in human breast milk. However the contamination by aflatoxin M1 and ochratoxin A were the most investigated by several countries.Scope and approachTo scrutinize all papers reporting quantitative data on the prevalence and the levels of mycotoxins and their metabolites in breast milk, also the circumstances of exposure.A systematic literature search in Pubmed, Science direct and Google scholar databases were performed to identify relevant studies, published in English from 1984 through May 2015.Key findings and conclusion63 studies met the inclusion criteria and assessed the occurrence of 29 mycotoxins & their metabolites in breast milk, regarding 7194 subjects of 31 countries. The maternal dietary habits, the socio demographic status of the mother, the seasonal variations and the sensitivity of the analytical method were the factors related to the high concentrations of AFM1 and OTA in breast milk.Studies where contamination exceeds maximum limits and exhibit real risk of public health were highlighted.  相似文献   
10.
分析了一台600MW机组的加氧处理转换过程,明确了转换前的工作。整个系统的转换时间约4天,加氧初期水汽系统的电导率上升,氧量平衡后,水汽系统的电导率和含铁量大大降低,省煤器入口给水铁含量从16μg/L降低至小于4μg/L,其它水汽样的含铁量也降低至小于5g/L,后期给水的pH值调节至8.4~9.0,加氧转换取得成功。  相似文献   
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