微晶化对TiAl抗高温氧化性能的影响

研究了微晶化对TiAl金属间化合物在800～900℃抗恒温及循环氧化性能的影响铸态和微晶TiAl在800～900℃下均形成TiO2和Al2O3的复合氧化物膜，恒温氧化动力学均近似服从抛物线规律，微晶化对TiAl的恒温氧化性能无明显影响，但微晶化通过改善氧化膜的粘附性提高了TiAl的抗循环氧化能力     

浅谈平原水库井点降水及封填降水井的施工方法

1 概况 禹城市位于德州市南部.徒骇河中游.新建的李三尖水库位于禹城市房寺镇东南部,徒骇河以北的老苇河河道上,距市区4km.水库总库容为1168万m3,设计蓄水深9m,库底高程17.5m,充库泵站提水能力为8m3/s,枢纽工程为三等.主要建筑物为3级,地震设防裂度为7度.围坝轴线长6.696km,坝顶高程27.6m,防浪墙顶高程28.6m,坝顶宽7.0m,坝内坡高程21.5m设10m宽平台,围坝上、下游边坡均为1:3,水库最高蓄水位26.5m,死水位18.5m.     

金属间化合物的高温腐蚀与防护

综述了有序金属间化合物，主要是Ｎｉ－Ａｌ，Ｔｉ－Ａｌ和Ｆｅ－Ａｌ系金属间化合物高温腐蚀与防护方面的研究结果，包括它们的氧化腐蚀机理、合金元素对其氧化腐蚀性能的影响以及它们所需的高温涂层等。     

确定零件强度和疲劳强度许用值的一种方法

本文根据机器零件强度和疲劳强度的模拟试验,用概率论及相关函数对试验数据进行处理,提出用99.7%的零件不破坏概率时的强度值和疲劳强度值作为其许用值。用这种方法确定的许用值,在设计机器零件时既能保证机器零件不破坏和安全可靠,也充分利用了材料强度,避免了设计者在选取安全系数存在随意性太大的缺点。     

Feature selection based on mutual information: criteria of max-dependency, max-relevance, and min-redundancy

Feature selection is an important problem for pattern classification systems. We study how to select good features according to the maximal statistical dependency criterion based on mutual information. Because of the difficulty in directly implementing the maximal dependency condition, we first derive an equivalent form, called minimal-redundancy-maximal-relevance criterion (mRMR), for first-order incremental feature selection. Then, we present a two-stage feature selection algorithm by combining mRMR and other more sophisticated feature selectors (e.g., wrappers). This allows us to select a compact set of superior features at very low cost. We perform extensive experimental comparison of our algorithm and other methods using three different classifiers (naive Bayes, support vector machine, and linear discriminate analysis) and four different data sets (handwritten digits, arrhythmia, NCI cancer cell lines, and lymphoma tissues). The results confirm that mRMR leads to promising improvement on feature selection and classification accuracy.     

In Situ Scanning-Tunneling-Microscope Observation on Dissolution of a Cu-20Zr Film

A nanocrystalline coating of Cu-20Zr (in wt pct) was obtained on glass by magnetron sputtering. The corrosion behavior of the Cu-20Zr film in 0.001 mol/L HCI solution was investigated using potentiodynamic polarization and in situ electrochemical scanning-tunneling-microscopy (ECSTM). Results demonstrated that the film exhibits active behavior. Microscopic pitting corrosion and tunneling are caused by localized electrodissolution of Zr atoms and the diffusion of Cu atoms at surface defects.     

纳他霉素处理对鲜切双孢菇褐变的抑制机理

为研究纳他霉素对鲜切双孢菇褐变的抑制机理,本实验分别采用去离子水（对照）、0.1?g/kg纳他霉素和复合试剂（0.1?g/kg纳他霉素＋10?g/kg?D-异抗坏血酸钠）浸泡处理鲜切双孢菇5?min,并于4?℃下贮藏,分析贮藏过程中多酚氧化酶（polyphenol oxidase,PPO）、酪氨酸酶（tyrosinase,TYR）活力和自由基清除率等多项生理指标。结果表明：纳他霉素和复合试剂处理均能抑制鲜切双孢菇贮藏过程中硬度下降及质量损失率、呼吸强度和相对电导率的上升,降低霉菌和酵母总数,延缓PPO和TYR活力的上升,维持双孢菇子实体VC、还原性谷胱甘肽、总酚和羟脯氨酸含量及谷胱甘肽还原酶和苯丙氨酸解氨酶的活力,有利于双孢菇保持较高的抗氧化酶活力、自由基清除率和总抗氧化能力,从而减轻双孢菇的褐变程度,延长其货架期,其中复合试剂处理的效果更佳。     

纳米Fe-10Cr涂层电化学腐蚀行为影响研究Ⅱ.点蚀性能

利用动电位极化曲线、电化学阻抗谱图（EIS）和Mott-Schottky分析等电化学测试手段．探讨了Fe—10Cr纳米涂层在0.05mol／L H2SO4＋0.5mol／LNaCl溶液中的腐蚀行为．研究表明，与铸态合金相比，溅射纳米涂层表面钝化膜的化学稳定性和再钝化性能明显提高；二者的钝化膜均具有p型半导体结构特征．但溅射纳米涂层表面钝化膜的载流子密度和平带电位都比较低，导致钝化膜中金属离子的传输速度较低，纳米橡层表面钝化膜的化学稳定性增强。     

Protective performance of epoxy resin modified with coal tar coating studied by electrochemical impedance spectroscopy

The effect of different amounts of titanium powder, used as additive, on the protective performance in aqueous 3.5 wt.% sodium chloride solution of coal tar epoxy resin cured with polyamine has been studied by electrochemical impedance spectroscopy (EIS). In this paper, the electrochemical impedance spectra and breakpoint frequency (f_b) of the coating as a function of titanium content and immersion time, and the electrical resistance of the coating by calculating permittivity of the coating were analyzed and discussed. It is shown that EIS performance of the coating can be explained by change of the permittivity of the coating with time, and the protective performance (the protective life) is determined by the breakpoint frequency of the coating in given system.     

高Si压铸Al合金ADC12的微弧氧化表面改性

利用恒流微弧氧化技术,在以Na2SiO3和Na3PO4为主盐的电解液中,在高硅压铸Al合金ADC12表面制备了陶瓷膜．显微硬度及耐蚀性能测试表明,陶瓷膜显微硬度（HV）高达1430,能对基体金属提供有效的防护．涡流测厚及SEM研究显示,该陶瓷膜厚度分布比较均匀,具有双层结构．EDX和XRD分析表明,该微弧氧化陶瓷膜的主要元素组成为0,Al,Si和P;主要相组成为γ-Al2O3和α-Al2O3,同时含有少量χ-Al2O3,θ-Al2O3和Al2SiO5晶体．