Windows应用程序界面设计的若干问题

界面设计是软件开发的重要组成部分，本文论述了实现美观、实用的用户界面必须注意的几个问题，如界面设计的美学原则、可用性设计的概念、当用户或系统出错时的用户交互形式、帮助使用的用户辅助模式以及为使应用程序运行于不同计算机的显示类型设计。     

Retention of clay-solidified grouting curtain to Cd~(2 ), Pb~(2 ) and Hg~(2 ) in landfill of municipal solid waste

1　INTRODUCTIONIntheseyears ,innocuitytreatmentofmunicipalsolidwaste (MSW )hasincreasedgreatlyand 95 %isattributedtosanitaryandsemi sanitarylandfillswiththelandfillsbeingconstructedinarapidprogressinChina.Itisveryimportantforlandfillsto preventseepageofleachateincludingheavymetalsfromlandfillsintotheenvironment.Manyresearchershavestudiedtheanti seepagetechnology .Forexample ,Philip[1 ] investigatedcontaminationtransportprocessthroughsingle phasecement bentoniteslurrywallbytriaxialcelle…     

低压离子色谱法同时测定水中铜(Ⅱ)、锌(Ⅱ)和铁(Ⅱ)

在低交换容量0．02mol／L的低压阳离子分离柱上选用40mmol／L酒石酸-20mol／L柠檬酸(pH4．30)的洗脱液分离微量Cu^2 、Zn^2 和Fe^2 离子，以吡啶-(2-偶氮-4-)雷琐辛(PAR)作显色剂，在波长520nm处连续检测，得到线性良好的工作曲线，铜、锌和铁最低检测限分别为0．02μg/ml，0、05μg/ml和0．06μg/ml。利用该方法分析了环境水样中的铜、锌和铁，回收率分别为99．0％～102.0％，97．0％～104．0％，98．0％～104、0％。     

火焰原子吸收法研究酵母菌对Cu2+的吸附作用

用火焰原子吸收分光光度法研究了酵母菌对Cu2 的生物吸附作用.酵母菌能有效结合Cu2 ,10 min即可达到吸附平衡.pH为5～6时吸附效果较好.盐度及Ca2 、Na 等离子对吸附量稍有影响,升温有利于吸附.随着初始Cu2 浓度的升高,吸附量也逐渐增大.该吸附符合Langmuir等温吸附方程,最大吸附量和表观吸附平衡常数分别为1.32 mg·g-1、0.189 L·mol-1.     

Electrochemical characterization of alternate conducting carbazole-bisthiophene units

An electrochemical and theoretical character of alternate copolymer of carbazole and bithiophene units was investigated. Polymerization is processed as two steps bielectronic oxidation of molecule. With monoelectronic oxidation is connected stable radical cation with spin located mainly on carbazole. The electrochemical properties of polymer are dependent on thickness of film deposited on electrode. In case of the thin layers one it is observed characteristic redox couple of carbazole oxidation to radical cation. Analysis of polymer behavior and results of spectrochemical measurements indicate on mixed type of electroconductivity.Molecular structures, HOMO-LUMO gaps and nature of highest occupied and lowest unoccupied molecular orbitals were also studied in presented work for oligomers ranging from monomer to octamer. The studies applied density functional theory (DFT).     

Effect of abruptly changing withdrawal rate on solidification microstructure in directionally solidified Al-4.5wt%Cu alloy简

Al-4.5wt.%Cu alloy has been directionally solidified at constant and abruptly changing withdrawal rates, respectively. The effects of the withdrawal rate on solidification microstructure, primary dendrite arm spacing(PDAS) and liquid solute distribution in front of the solid-liquid interface were investigated. The experimental results for the PDAS at a constant withdrawal rate agree well with the values calculated by the Hunt, Trivedi and Hunt-Lu models. At an abrupt change in the withdrawal rate, the maximum to minimum ratio of the PDAS at a given solidification parameter, i.e. λ1max/λ1min, is more than 2, and the PDAS values are remarkably history-dependent. Further, the liquid-solute distribution curve based on theoretical calculation shows that the larger the initial withdrawal rate is, the smaller the minimum of liquid solute concentration in front of the solid-liquid interface is after the abrupt change in withdrawal rate.     

Efficiency enhancement by mixed cation effect in dye-sensitized solar cells with a PVdF based gel polymer electrolyte

This paper reports the effect of using a mixed iodide salt system with two dissimilar cations to enhance the efficiency of dye-sensitized solar cells made with polyvinylidenefluoride (PVdF) based gel electrolyte. Instead of a single iodide salt, a mixture of potassium iodide (KI) with a small K⁺ cation and tetrapropylammonium iodide (Pr₄NI) with a bulky Pr₄N⁺ cation were used to provide the required iodide ion conductivity. Solar cells of configuration FTO/TiO₂/Dye/electrolyte/Pt/FTO were fabricated using a mesoporous TiO₂ electrode sensitized with a Ruthenium dye (N719). With identical electrolyte compositions, the cells with KI and Pr₄NI alone gave efficiencies of 2.37% and 2.90% respectively. The cell with the mixed iodide system, KI:Pr₄NI = 16.6:83.4 (% weight ratio), however, showed an enhanced efficiency of 3.92% with a short circuit current density of 9.16 mA cm⁻², open circuit voltage of 674.4 mV and a fill factor of 63.4%.     

Element segregation behavior of aluminum-copper alloy ZL205A

In aluminum-copper alloy, the segregation has a severe bad effect on the alloying degree, strength and corrosion resistance. A deeper understanding of element segregation behavior will have a great significance on the prevention of segregation. In the study, the element segregation behavior of ZL205A aluminum-copper alloy was investigated by examining isothermally solidified samples using scanning electron microscopy and energy dispersive spectroscopy. The calculated results of segregation coefficients show that Cu and Mn are negative segregation elements; while Ti, V and Zr are positive segregation elements. The sequence of element segregation degree from the greatest to the least in ZL205A alloy is Cu, Mn, V, Ti, Zr and Al. The density of residual liquid is expected to increase with a decrease in the quenching temperature ranging from 630℃ to 550 ℃. The calculated results confirm that the quenching temperature has an insignificant effect on the liquid density; and the variation of density is mainly due to element segregation. Consequently, segregations of Al, Cu and Mn lead to an increase in density, but Ti, V and Zr present the opposite effect. The contribution of each element to the variation of the liquid density was analyzed. The sequence of contributions of alloying elements to the variation of total liquid density is Cu〉Al〉Mn〉V〉Ti〉Zr.     

Computational study for the circular redox reaction of N2O with CO catalyzed by fullerometallic cations C60Fe+ and C70Fe+

We applied density functional calculations to study the circular redox reaction mechanism of N₂O with CO catalyzed by fullerometallic cations C₆₀Fe⁺ and C₇₀Fe⁺. The on-top sites of six-membered rings (η⁶) of fullerene cages are the most preferred binding sites for Fe⁺ cation, and the hexagon to pentagon migration of Fe⁺ is unlikely under ambient thermodynamic conditions. The initial ion/molecule reaction, N₂O rearrangement and N₂ abstraction on the considered fullerometallic cations are easier than those on the bare Fe⁺ cation in the gas phase. Generally, our results indicate that fullerometallic ions, C₆₀Fe⁺ and C₇₀Fe⁺, are more favorable substrates for redox reaction of N₂O with CO in comparison to the other previously studied carbon nanostructures such as graphene and nanotubes.     

阳离子对阴离子型乳化沥青储存稳定性的影响

在阴离子型乳化沥青中分别添加NaCl和CaCl2电解质,考察Na+,Ca2+阳离子对阴离子型乳化沥青储存稳定性的影响规律.通过分析电解质掺加前后阴离子型乳化沥青zeta电位、粒径分布和微观形貌的变化,探讨Na+,Ca2+阳离子对阴离子型乳化沥青储存稳定性的影响机理.结果表明：Na+对阴离子型乳化沥青的储存稳定性无明显影响,而Ca2+则显著降低阴离子型乳化沥青的储存稳定性,且影响程度随Ca2+浓度提高而呈上升趋势.Ca2+吸附并聚集在沥青微粒周围,降低了沥青微粒间的静电斥力,导致沥青微粒聚集,最终降低了阴离子型乳化沥青的储存稳定性.在阴离子型乳化沥青生产用水中Ca2+浓度不宜超过1.9mmol/L,且不宜使用可电离出Ca2+的添加剂.