羟基含量对木素磺酸钙表面物化性能的影响

研究了木素磺酸钙(CLS,简称木钙)分子中羟基含量对其表面活性、吸附性能、分散性能等表面物化性能的影响。结果发现,木钙分子中羟基含量增加后,其表面活性提高,在木钙溶液质量浓度为2.0g/L时能形成胶束,同时木钙溶液起泡能力增强,稳泡能力显著提高,吸附能力增强;当木钙溶液质量浓度为16g/L、其分子中羟基相对含量为2.55时,木钙在水泥颗粒表面的吸附量可增加6.9倍,但分散能力下降。木素磺酸阴离子对钙离子具有络合作用,羟基含量增加,其络合能力增强。

电热载荷对碳纤维表面物化性质的影响

目的探索用低强度电流(毫安级)处理碳纤维单丝的实验方法,讨论电热载荷对碳纤维表面物化性质的影响,为碳纤维复合材料电热损伤机制研究提供理论基础。方法采用直流恒流精密电源对T300碳纤维单丝以不同强度的电流通电,利用扫描电子显微镜(SEM)和原子力显微镜(AFM)测试手段分析碳纤维表面形貌和粗糙度的变化,利用X射线光电子能谱(XPS)对电热处理后的碳纤维表面的化学性质进行分析,并得出纤维表面活性的变化。结果经过不同电流强度处理的碳纤维表面发生了明显的变化,2 m A和4 m A处理的纤维表面出现了很多裂纹,且粗糙度随着电流的升高而降低,6 m A处理的纤维表面沟壑被填充且粗糙度稍有上升;随着电流的升高,纤维表面的C含量随之升高,O含量则呈现相反趋势,C—C稍有降低,C—O键降低明显。结论电热载荷对纤维表面的浆料有烧蚀作用,未反应的浆料残留在碳纤维表面,并且使凹槽变浅,粗糙度也有所降低;电热产生的高温反应掉了很多上浆剂成分,使更多的纤维本体裸露出来,更多的羟基转化成了羰基和羧基,而纤维表面活性则稍有增强。

表面物化性质于均质滤料过滤性能的影响

悬浮颗粒和滤料表面ζ电位的变化能使悬浮颗粒和滤料表面的物化性质得到改变,显著改善了滤料过滤性能.实验表明,各种水处理药剂对颗粒表面的ζ电位值的改变存在最佳值,过高或过低的ζ电位,滤料的过滤性能差;当ζ电位值达某一值时,滤池的除浊效果最理想.当投加阳离子高分子电解质作主混凝剂或助凝剂,颗粒及滤料表面ζ电位将发生逆转或降低,从而改善了滤池的过滤性能.

碳化硅量子点表面物化特性调控及其光学特性

采用化学偶联法,通过调整腐蚀剂组分及其相对含量,一步法实现了碳化硅量子点(SiC-QDs)表面物化特性的有效调控。研究表明:经硝酸(HNO_3)和氢氟酸(HF)混合腐蚀剂腐蚀纳米β-SiC粉末,通过超声空化破碎分散及高速离心处理,可获得SiC-QDs水相溶液,并一步法实现了表面修饰,在其表面形成了—COO、—OH等亲有机物功能基团。采用浓硫酸(H_2SO_4)为偶联剂,制备出表面具有巯基(—SH)的SiC-QDs水相溶液。腐蚀剂组分的相对含量对于SiC-QDs的光致发光强度与表面巯基的形成影响较大。在波长为340 nm的激发光激发下,SiC-QDs具有最大的发光强度,随着腐蚀剂中H_2SO_4含量的增加,其光致发光强度呈现降低趋势。当腐蚀剂的体积比为V(HF):V(HNO_3):V(H_2SO_4)=6:1:1时,制备的水相SiC-QDs表面既能稳定耦合—SH,又可以获得较高的光致发光强度。另外,对表面物化特性调控及其形成机制进行了分析研究。

不对称亚砜类表面活性剂的合成,物性及其应用

在汇集大量文献资料的基础上，归纳出制备亚砜类表面活性剂的三种方法，列出了其表面物化性能数据及在有关领域中的应用，指出了对这一课题进行研究的重要意义。

Laser processing effects on Ti−45Nb alloy surface,corrosive and biocompatible properties

The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface.The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment.Nevertheless,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mJ was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer.Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability,morphology,and proliferation were also investigated.The Ti−45Nb alloy showed no cytotoxic effect.Moreover,cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment.The highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 mJ.Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.

木素磺酸钙的氧化改性研究

研究了木素磺酸钙 (简称木钙 )的氧化改性工艺 ,比较了几种氧化剂与木钙反应后性能的差异。结果表明 ,过氧化氢对木钙的聚合或降解作用均较弱 ,过硫酸铵在适宜的条件下可使木钙发生聚合反应 ,并显著改善木钙的表面物化性能。过硫酸铵氧化木钙时 ,适宜的氧化条件是过硫酸铵的用量为 4%～ 6 % ,反应温度为 80～ 90℃ ,pH =8～ 10。初步探讨了木钙的氧化聚合机理 ,过硫酸铵在碱性条件下使木钙酚型物发生离子化脱氢 ,产生了游离基 ,从而提高了木钙的反应活性 ,促进了木钙分子游离基之间的聚合反应。

量子点对活体细胞毒性作用的研究进展

综述了近年来国内外对镉系量子点细胞毒性的研究进展,对于大部分活体细胞镉系量子点普遍存在毒性,总结了细胞毒性产生的原因主要表现在三个方面:量子点表面物化特性、量子点尺寸和细胞微环境,由于细胞毒性的影响因素较多而较难控制,研发低毒甚至无毒的量子点材料成为业内研究者的共识。对近年来开发的新型SiC量子点生物毒性的研究进展进行了介绍,认为其生物相容性优良的主要原因在于:表面物化特性可控、细胞微环境对以共价键结合的量子点影响较小以及细胞内分布均匀等,同时对目前碳化硅量子点细胞毒性研究存在的问题也进行了分析探讨。

交联粘土催化剂的研究进展

交联粘土催化剂具有巨大的比表面和独特的孔结构 ,且价格低廉 ,是一种良好的催化材料。本文叙述了交联催化剂的存在性质及柱对粘土表面物化性能的影响 ,同时介绍了催化剂的应用情况。

Comparative studies of leached Pt-Fe and Pt-Co catalysts for CO oxidation reactions

Leached Pt-Fe and Pt-Co catalysts were prepared by acid leaching the reduced catalysts in acid solution. Oxidation treatments of leached catalysts produced the structure o f metal oxides decorat-ing the surface of nanoparticles. The fully oxidized Fe2O3 and Co3O4 species on Pt nanoparticle sur-faces result in the low performance of the CO complete oxidation （COOX） reaction. In contrast, un-saturated FeO and CoO surface species can be formed during exposure to the CO preferential oxida-tion （CO-PROX） reaction with an excess of H2, leading to a high O2 activation ability and enhancing the CO-PROX activity. The FeOx surface structures can be transformed between these two states by varying the reactive gas environments, exhibiting oscillating activity in these two reactions. Con-versely, the CoO surface structure formed in the H2 -rich atmosphere is stable when exposed to the COOX reaction and exhibits similar activity in these two reactions. It is hoped that this work may assist in understanding the important role of surface oxides in real reactions.

Surface species of chalcopyrite during bioleaching by moderately thermophilic bacteria

X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） analyses were carried out to investigate the surface species and interfacial reactions during bioleaching of chalcopyrite by different strains of moderately thermophilic bacteria （45 °C）. Results show that monosulfide （CuS）, disulfide （S22？）, polysulfide （Sn2？）, elemental sulfur （S0） and sulfate （SO42？） are the main intermediate species on the surface of chalcopyrite during bioleaching byA. caldus,S. thermosulfidooxidans andL. ferriphilum. The low kinetics of dissolution of chalcopyrite inA. caldus can be mainly attributed to the incomplete dissolution of chalcopyrite and the passivation layer of polysulfide. Polysulfide and jarosite should be mainly responsible for the passivation of chalcopyrite in bioleaching byL. ferriphilumorS. thermosulfidooxidans. However, elemental sulfur should not be the main composition of passivation layer of chalcopyrite during bioleaching.

The Effect of Baffled Surface Flow Wetlands on Water Purification

[Objective] The effect of baffled surface flow wetlands on water purification was studied in order to provide a reference for the ecological restoration of polluted river.[Method] Contents of some indexes like DO,TN,TP,NH＋4-N,CODCr,SS,SD,etc.were determined in the band baffled surface flow wetlands with total area of 7 400 m2 at JiaLu riverside.[Result] Baffled surface flow wetlands could improve the effluent quality significantly,could enhance transparency and dissolved oxygen content and also could decrease SS content.The removal rate of TN was kept at more than 73% in summer and decreased to 23% in early winter;The removal rate of TP was little influenced by temperature,and it was kept at more than 77% in summer and still kept at more than 69% in autumn and winter;The removal rate of NH＋4-N was kept at more than 83% in summer and decreased slightly in autumn and winter,but still kept at more than 75%;The removal rate of CODCr ranged from 14% to 50%.[Conclusion] Baffled surface flow wetlands could effectively improve the purification effect of surface flow wetlands,which is a feasible way for ecological restoration.

First-principles thermodynamics of metal-oxide surfaces andinterfaces:A case study review

An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed.

Calculating models on surface tension of RE_2O_3-Mg O-SiO_2(RE=La, Nd, Sm, Gd and Y) melts

A thermodynamic model was developed for determining the surface tension of RE2O3-MgO-SiO2(RE=La, Nd, Sm, Gd and Y) melts considering the ionic radii of the components and Butler's equation. The temperature and composition dependence of the surface tensions in molten RE2O3-MgO-SiO2 slag systems was reproduced by the present model using surface tensions and molar volumes of pure oxides, as well as the anionic and cationic radii of the melt components. The iso-surface tension lines of La2O3-MgO-SiO2 slag melt at 1873 K were calculated and the effects of slag composition on the surface tension were also investigated. The surface tensions of La2O3, Gd2O3, Nd2O3 and Y2O3 at 1873 K were evaluated as 686, 677, 664 and 541 m N/m, respectively. The surface tension of pure rare earth oxide melts linearly decreases with increasing cationic field strength, except for Y2O3 oxide, while Y2O3 has a much weaker surface tension. The evaluated results of the surface tension show good agreements with literature data, and the mean deviation of the present model is found to be 1.05% at 1873 K.

Influence of CO2 on Oxygen Surface Exchange Kinetics of Mixed- Conducting Ba0.5 Sr0.5 Co0.8 Feo.2O3_δ Oxide

The poisoning effect of CO2 on the oxygen surface exchange kinetics of BSCF （Ba0.5 Sr0.5 Co0.8 Feo.2O3_δ） is investigated with a novel pulse isotopic exchange technique. The surface exchange rate of BSCF severely decreases after in situ exposure to CO2, which is ascribed to carbonate formation on the material surface. The detrimental effect of CO2 starts at a low temperature of 375 ℃ and concentration as low as 1%, and becomes more pro- nounced at higher temperatures. Degradation of the surface exchange kinetics is associated with a rapid loss of oxygen permeation performance of BSCF in CO2.

Investigation on the Antitumor Activity of Organotin Compound

Changes in the surface structure of cell membrane and the contents of membrane pro- teins and nuclear DNA of human gastric cancer (BGC-823) cells treated with organotin compound (Et_2SnCl_2phen) were studied with a scanning electron microscope (SEM),a scanning tunneling,micro- scope (STM),and a cytofluorophotometer.It was found that Et_2SnCl_2Phen not only inhibited the cell growth but also remarkably changed the surface structure of the membrane of cancer cells.The surface of Et_2SnCl_2phen treated cancer cells was relatively smooth and showed fewer microvilli under SEM. STM images showed an uneven and loose distribution of the surface of the cell.In comparison with the untreated cancer cells,there was an evident decrease in the content of membrane proteins and nuclear DNA in Et_2SnCl_2phen treated cells.

Oxygen adsorption on pyrite (100) surface by density functional theory

Pyrite （FeS2） bulk and （100） surface properties and the oxygen adsorption on the surface were studied by using density functional theory methods. The results show that in the formation of FeS2 （100） surface, there exists a process of electron transfer from Fe dangling bond to S dangling bond. In this situation, surface Fe and S atoms have more ionic properties. Both Fe2+ and S2- have high electrochemistry reduction activity, which is the base for oxygen adsorption. From the viewpoint of adsorption energy, the parallel form oxygen adsorption is in preference. The result also shows that the state of oxygen absorbed on FeS2 surface acts as peroxides rather than O2.

Photocatalytic degradation of 2,4-dichlorophenol with V_2O_5-TiO_2 catalysts: Effect of catalyst support and surfactant additives

Binary oxide catalysts with various weight percentage V2O5 loadings were prepared by solid‐state dispersion and the nanocomposites were modified with surfactants. The catalysts were analyzed using X‐ray diffraction, diffuse‐reflectance spectroscopy, Fourier‐transform infrared spectroscopy, scanning electron microscopy, and N2 adsorption‐desorption. The photocatalytic activities of the catalysts were evaluated in the degradation of 2,4‐dichlorophenol under ultraviolet irradiation. The photocatalytic activity of 50 wt%V2O5‐TiO2 （50V2O5‐TiO2） was higher than those of pure V2O5, TiO2, and P25. Interactions between V2O5 and TiO2 affected the photocatalytic efficiencies of the binary oxide catalysts. Cetyltrimethylammonium bromide （CTAB） and hexadecyltrimethylammonium bromide （HTAB） significantly enhanced the efficiency of the 50V2O5‐TiO2 catalyst. The highest per‐centage of 2,4‐dichlorophenol degradation （100%） and highest reaction rate （2.22 mg/（L·min）） were obtained in 30 min with the （50V2O5‐TiO2）‐CTAB catalyst. It is concluded that the addition of a surfactant to the binary oxide significantly enhanced the photocatalytic activity by modifying the optical and electronic properties of V2O5 and TiO2.

The use of in-situ cosmogenic ^(21)Ne in studies on long-term landscape development

Cosmogenic Ne isotopes are stable and are routinely used for constraining the timing of events and the rate of surface change beyond the limit that can be studied with radionuclides ^10Be, ^26Al, and ^36Cl. Cosmogenic Ne analysis can be used in quartz and in a range of other minerals. Analysis typically requires significantly less material than do cosmogenic ^10Be and ^26Al, opening up the technique for small samples--individual pebbles in fiver sediments, for example. Analysis is easier and faster than for radionuclides, not least because Ne measurements do not require significant chemical procedures. However, the presence of other sources of Ne in minerals tends to restrict the use of cosmogenic ^21Ne to old landscapes and long exposure durations. In this review we briefly outline the background of cosmogenic Ne production in rocks and minerals at the Earth＇s surface, then document the key uses of the technique by highlighting some earlier studies, and finish with a short perspective on the future of the technique.