Special Issue: Photoelectrochemistry and New Types of Solar Cells Future Green Renewable Energy Resources

众所周知,能源与环境是当今人类面临的最大难题和挑战,随着世界能源需求的急剧攀升,传统化石资源的不断耗竭,全球温室效应和环境污染的压力日趋严重,发展各种可再生绿色能源成为当今世界最主要的共性问题和研究热点.太阳能光电转化技术被认为是一种最有希望真正解决未来社会可再生能源和洁净环境问题的先进技术.太阳可为人类提供取之不尽、用之不竭的巨大能源宝库,每年照射到地球的太阳能量高达174000 TW,换言之,只要能以10%效率转化0.1%到达地球表面的太阳能,即可满足全

The Fe-doped TiO_2 Nanotube Arrays as a Photoanode for Cathodic Protection of Stainless Steel

在含FeSO4的HF、H2SO4/HF、NaF/Na2SO4溶液中,通过电化学阳极氧化直接在纯钛表面制备Fe掺杂的TiO2(Fe-TiO2)纳米管阵列.应用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见吸收光谱(UV-Vis)、X射线光电子能谱(XPS)等手段对纳米管阵列的结构、形貌及化学组成进行表征.利用光电化学测量研究Fe-TiO2纳米管阵列在不同波长范围内的光电响应特性和光生阴极保护行为.考察了温度、时间、掺杂含量等参数对TiO2纳米管阵列的几何尺寸、形貌和光电性能的影响.结果表明,Fe掺杂可有效减缓TiO2纳米管阵列载流子的复合,窄化TiO2带隙宽度,Fe-TiO2在410-650nm范围显示强吸收,并使光谱响应扩展到波长大于400nm的可见光区.实验结果还表明,Fe-TiO2纳米管阵列对316不锈钢(316L)具有良好的光生阴极保护作用,暗态下阴极保护作用可继续维持.A highly ordered Fe-doped TiO2 nanotube layer was fabricated by potentiostatic anodization of pure titanium in fluorinated electrolyte solutions containing iron ions.The structure and composition of the as-prepared TiO2 nanotubes were characterized by SEM,XRD,UV-Vis,and XPS.The effects of temperature,time,dopant content on the morphologies,structure and photochemical properties of the TiO2 nanotube arrays were investigated systemically.The performances of photogenerated cathodic protection and the photoelectrochemical response for the Fe-doped TiO2 nanotube layers under illumination and dark conditions were evaluated through the electrochemical measurements.It was found that Fe ions in the TiO2 nanotube arrays could suppress the recombination of photogenerated hole-electron.The Fe-doped TiO2 nanotubes showed a stronger absorption in the 410-650 nm range.The open-circuit potentials of 316L SS(stainless steel)coupled with the Fe-doped TiO2 nanotubes layers shifted negatively under visible light irradiation(>400 nm),and maintained negatively for a period even in dark condition.It was indicated that the Fe-doped TiO2 nanotubes layers were able to create effectively a photogenerated cathodic protection for metals under regular sunlight conditions.国家自然科学基金(50571085);; 国家科技部基础研究资助项目(2005CCA06700)资

聚合物太阳能电池发展与展望

在目前的世界能源结构中,人类所利用的主要是石油、煤炭、天然气等化石能源,这些化石能源大约占到人类能源消费总量的80%。根据英国bP石油公司发布的全球能

Fluorescence properties and color space of modifying porcelains

目的:探讨色参数差值与荧光发射量的相关性。方法:在Color-Eye7000A分光光谱仪上,用4种模式测定Vita Interno、Shofu Vintage&Unibond和Noritake Super Porcelain EX-3套装染色瓷粉的色参数,建立其CIE LAB色度空间坐标图;计算荧光发射量和反射光谱波长。用完全随机两因素方差分析和SNK-q检验(α=0.05),比较样本荧光发射量之间的差异,建立荧光发射量与色参数差之间的相关性分析(α=0.05)。结果:Vita与Shofu,Vita与Noritake的荧光发射量差别有统计学意义(P<0.05)。荧光发射量与色参数差值之间的相关性有统计学意义(P<0.05)。荧光光谱反射峰值均处于400nm附近。染色瓷粉的色度空间总体分布趋势为:Vita染色瓷粉的明亮度较高,且偏红-黄方向,Noritake偏绿-蓝方向,而Shofu居中。结论:测量模式对测定没有影响;Shofu和Noritake的荧光发射量比Vita大;染色瓷粉所发出的荧光偏紫色;3种套装染色瓷粉的CIE LAB色度空间有差别;荧光发射量与色参数差值总体上相关。Objective:To investigate the correlation between fluorescence emission and color difference (CIE△Eab). Methods:Color and spectral distribution in three kinds of modifying porcelains (Vita Interno, Shofu Vintage & Unibond, Noritake Super Porcelain EX-3) were measured on CIELAB color scale on Color-Eye 7000A spectrophotometer under four measuring modes. CIE△Eab were analyzed by two-way ANVOA and SNK-q test (α=0.05). Correlation analyses were also performed between CIE△Eab and the color parameters difference(α= 0.05). In addition, CIELAB color coordinate was established. Results:Fluorescence emission of Vita and Shofu, Vita and Noritake were significantly different(P<0.05). Fluorescence emission and the color parameters difference showed correlationship(P<0.05). The emission wavelength of fluorescence was about 400 nm. There were differences of three kinds of porcelain in color space. The total tendency of color space as follows: Vita owned higher value and was in red-yellow direction; the shade of Noritake was in blue-green direction, while color scale of Shofu was in the middle of the previous codes.Conclusion:Specular component included versus specular component excluded modes have no effects on fluorescence emission. The fluorescence values of Shofu and Noritake were larger than that of Vita. The shade of fluorescence was purple.福建省卫生厅科技联合攻关项目(编号:3502Z8021

Measurement and analysis of reflected fluorescence of opal porcelains

目的对Ceramco、Shofu、Noritake和Vita共22种不同颜色的乳光瓷样本的反射荧光进行测量和分析。方法采用分光光谱仪测量乳光瓷样本的L*、a*、b*值,计算反射模式下的荧光(色差)。绘制荧光光谱曲线。按品牌和颜色因素对反射荧光均值进行完全随机设计的方差分析,组间用SNK-q检验(α=0.05)。结果经方差分析,不同品牌乳光瓷粉的反射荧光均值总体不等或不全相等(P0.05)。结论4种品牌乳光瓷粉的平均反射荧光由大到小依此排列为:Noritake、Shofu、Ceramco、Vita。不同品牌乳光瓷的反射荧光光谱分布的差异主要表现在400nm以下,荧光峰值出现在390nm位置。Objective To measure and analyze the reflection fluorescence of four opal enamel porcelains.Methods Twienty two samples with differernt shades, which came from four opal enamel porcelains (Ceramco,Shofu,Noritake and Vita) were used. The CIE Lab of each sample was measured with Color- Eye 7000A spectrophotometer and the reflection fluorescence (color difference) of each sample was calculated and spectra curves were plotted. According to the product and the shade factors, the average values of the relfection fluorescence were compared by AVNOA, and the intergroups by SNK-q test (α=0.05).Results There existed statistical difference in reflection fluorescence among different prouducts (P0.05).Conclusion The sequence from high to low based on the average value of the reflection fluorescence was: Noritake, Shofu, Ceramco, Vita. The difference in the reflected fluorescence spectra distribution among different products lied below 400nm and the fluorescent peak appeared in 390nm

Evaluation of three transmission parameters of dental opal porcelains and the correlations among parameters

目的测量Ceramco、Shofu、Noritake和Vita等4个品牌22种不同颜色的乳光瓷样本的透明度、对比率和遮色效果3个透射参数,并比较其相关性,为正确选择及使用乳光瓷粉提供参考。方法在反射模式和不同背景下,采用分光光谱仪测量乳光瓷样本的L*、a*、b*值,计算色差、透明度参数(TP)和遮色效果(ME)。在400～750 nm光谱范围内测量样本的光反射率,计算对比率(CR)。TP、ME和CR等3个透射参数分别按品牌和颜色因素用完全随机设计的方差分析进行分析,组间比较用SNK-q检验(α=0.05);3个参数的相关性分析采用直线相关与回归分析和多元线性回归分析(α=0.05)。结果相同品牌不同颜色乳光瓷透射参数的均数总体不等或不全相等(P<0.05)。遮色效果与透明度参数、对比率与透明度参数、遮色效果与对比率的相关性都具有统计学意义(P<0.05)。透明度参数与其他参数的多元线性回归具有统计学意义(P<0.05),偏回归系数都有统计学意义(P<0.05),对比率对透明度参数的回归所起的作用最大。结论使用乳光瓷粉时,应根据其透射参数加以选择;对比率代表不透明度,反映乳光瓷的不透明特性,较遮色效果更具有代表性。Objective To measure the translucency parameter(TP),masking effect(ME),and contrast ratio(CR) of opal porcelain of Ceramco,Shofu,Noritake,and Vita,and to compare the correlations among the three transmission parameters,in order to provide reference for selecting opal porcelain correctly.Methods The color of specimens was measured according to CIE L*a*b* under different background and reflectance mode with a Color-Eye 7000A spectrophotometer.The color difference,TP,and ME value were calculated.Within 400-750 nm spectra,the ratio of light reflectance was measured,and CR was also calculated.The data was compared by ANOVA and SNK-q test(α=0.05).The correlation and multiple linear regression between TP,CR,and ME were analyzed(α=0.05).Results There were statistical difference with different shade of the same brands(P<0.05).The correlations between ME and TP,TP and CR,ME and CR were existed(P<0.05).TP was correlated not only with ME but also with CR based on multiple regression analysis(P<0.05).The partial correlation coefficients were statistically significant(P<0.05).CR was the main devotion to translucency parameter on multiple regressions.Conclusion It is recommended to select opal porcelains based on transmission parameters.CR value has an inner significance of opaque property of opal porcelain and can express opacity property of opal porcelain more appropriately than ME

基于词汇吸引与排斥模型的共现词提取

:共现词提取在信息挖掘和自然语言处理中有着十分重要的地位。而传统的共现词提取方法仅仅局 限在单一的一种统计量上,其结果十分不精确,需要人工再进行整理。本文提出了一种基于词汇吸引与排斥 模型的共现词提取算法,并通过将多种常用统计量进行组合,改进了算法的效果。在开放测试环境下,所提取 的共现词其用户感兴趣度为60187 %。将该算法应用于基于Web 的共现词检索系统,在速度和共现词的提取 精度上均取得了比较好的效果。福建省自然科学基金资助项目(A0310009) ;福建省重点科技资助项目(2001J005

Effect of Ferric Citrate on Microstructure and Corrosion Resistance of Micro-arc Oxidation Black Film on Mg-alloy AZ40M

利用二次微弧氧化法在AZ40M镁合金表面成功制备了黑色的氧化膜层,通过SEM、EDS和XRD表征了膜层的微观形貌和成分组成。结果表明,柠檬酸铁添; 加剂浓度可显著影响镁合金表面氧化膜的形貌、组成和厚度,添加剂浓度越高,膜层中的铁氧化物含量也越高,而对膜层厚度的影响则没有呈现出明显规律。同时,; 测试了0.1 mol/L; NaCl溶液中的电化学阻抗谱和动电位极化曲线,结果显示镁合金表面黑色膜层具有较好的耐蚀性,且膜层越厚,铁含量越少,膜层的耐蚀性越好。Black oxide films on Mg-alloy AZ40M were prepared by means of a two-step; micro-arc oxidation process in electrolytes of 15 g/L Na_3PO_4+ 3 g/L; NaF+5.6 g/L KOH and 20 g/L Na_3PO_4+5 g/L NaF with different additions; of ferric citrate respectively. The microstructure and composition of; the films were characterized by scanning electron microscope (SEM),; energy dispersive spectrometer (EDS) and X-Ray diffractometer (XRD). The; electrochemical corrosion property of the films was assessed by using; electrochemical impedance spectroscopy (EIS) and potentiodynamic; polarization curves in 0.1 mol/L NaCl solution. Results showed that the; concentration of ferric citrate strongly affects the surface morphology,; composition and thickness of the formed oxide films. The oxide films; have good corrosion resistance. The thicker oxide film with less iron; content presents better corrosion resistance.国家自然科学基

Study on Localized Corrosion Behavior of Reinforcing Steel by Scanning Microelectrode Technique

应用扫描微电极法原位测量了模拟混凝土孔隙液中钢筋表面微区的电位分布,并结合动电位极化曲线的测量,研究了钢筋的局部腐蚀行为及模拟混凝土孔隙液pH值和Cl-浓度对它的影响.结果表明,在饱和Ca(OH)2溶液中,钢筋处于钝态,其表面微区电位分布为动态平衡;溶液的pH值降低和外加一定浓度的Cl-后,钢筋表面微区电位分布随之变化.当表面微区电位分布出现固定的突出电位峰时,钢筋发生了点腐蚀.在pH=12.00,外加Cl-浓度为0.05 mol/L或pH值降至10.16的Ca(OH)2溶液中,钢筋表面去钝化,发生腐蚀.In this work,the scanning microelectrode technique and potentiodynamic polarization were used to study the localized corrosion behavior of the reinforcing steel in simulated concrete pore solution with different pH values and chloride ion concentrations.It has been found that the reinforcing steel bar exhibits different corrosion characteristics in different conditions.There are some unstable micro-pitting nuclei on the surface of the steel in pure saturated Ca(OH)_2 solution and the steel remains passivated.However,the potential distribution on the steel surface changes with the addition of Cl~-or/and the reduction of pH value in the solution.The pitting corrosion of the steel occurs quickly when there are some obvious stable potential peaks on the steel surface and the height of one or some maximum potential peaks increases with time.Steel depassivation initiates and the corrosion takes place when additional Cl~-concentration reaches 0.05 mol/L in the Ca(OH)_2 solution with pH=12.00 or the pH of the solution falls to 10.16.国家自然科学基金资助项目(20473066);; 福建省自然科学基金资助项目(E0210006);; 国家重点基础研究前期研究专项项目(2005CCA06700

Photoelectrocatalytic Property of Titanium Based TiO_2 Nanotube Array Electrode

应用电化学阳极氧化法在纯TI基底上制备高度有序的TIO2纳米管阵列,考察了TI/TIO2光阳极的光电化学响应。以苯酚溶液为目标污染物,研究TI/TIO2电极的光电催化性能,并与光催化性能进行比较。结果表明,该电极光电催化性能优于光催化性能,施加0.6V电压时,光电催化性能最好。电化学阻抗谱分析显示,光电催化和光催化降解过程的速控步骤均为表面反应步骤,外加偏压减小了界面电荷转移阻抗,提高了光生载流子的分离效率。TiO2 nanotube arrays were prepared by the electrochemical anodization on pure Ti surfaces,and their photoelectrochemical activity was examined.The photoelectrocatalytic property of Ti/TiO2 electrode was evaluated by the degradation of phenol aqueous solution and compared with its photocatalytic performance.The results demonstrated that the photoelectrocatalytic degradation rate of phenol solution for Ti/TiO2 electrode was higher than its photocatalytic degradation rate.The highest photoelectrocatalytic level could be achieved when the bias potential of 0.6V was applied on the Ti/TiO2 electrode.The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photocatalytic process or for the photoelectrocatalytic process.The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs.福建省自然科学基金(No.U0750015);福建省科技计划重点课题(No.2007H0031);厦门市科技计划(No.3502Z20073004)资助项