Preparation and properties of the SmOx/Rh(100) model surface

The preparation of SmOx/Rh(100) and CO adsorption on this model surface have been investigated with Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption spectroscopy (TDS). The oxygen adsorption on the SmRh alloy surface leads to the aggregation of Sm on the surface. The thermal treatment of this oxidized surface induces the further agglomeration of SmOx on the Rh(100) surface. Compared with CO TDS on the clean Rh(100) surface, three additional CO desorption peaks can be observed at 176, 331 and 600 K on the SmOx/Rh(100) surface. The CO desorption peak at 176 K may originate from CO adsorbed on SmOx islands, while the appearance of the CO adsorption peaks at 331 and 600 K, depending on the oxidation state of Sm, is attributed to CO species located at the interface of SmOx/Rh(100).     

Preparation and properties of the SmOx/Rh(100) model surface

The preparation of SmO_x/Rh(100) and CO adsorption on this model surface have been investigated with Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption spectroscopy (TDS). The oxygen adsorption on the SmRh alloy surface leads to the aggregation of Sm on the surface. The thermal treatment of this oxidized surface induces the further agglomeration of SmO_x on the Rh(100) surface. Compared with CO TDS on the clean Rh(100) surface, three additional CO desorption peaks can be observed at 176, 331 and 600 K on the SmO_x/Rh(100) surface. The CO desorption peak at 176 K may originate from CO adsorbed on SmO_x islands, while the appearance of the CO adsorption peaks at 331 and 600 K, depending on the oxidation state of Sm, is attributed to CO species located at the interface of SmO_x/Rh(100).     

甲醛在Ag(110)面上的非均相氧化

用热脱附谱、低能电子衍射和电子诱导脱附离子角度分布(ESDIAD)研究了甲醛与氧在Ag(110)面上的吸附和反应。结果表明,低温条件下每个吸附态氧原子能稳住几个甲醛分子,其中大部分在220K时以甲醛形式脱附。ESDIAD照片(225K)进一步证明了HCOOH_(a)中间体的存在,该中间体在235K进一步脱氢,在晶体表面上留下较稳定的吸附态甲酸脂(HCOO_(a))。在250K还出现一个水脱附峰和一个较小的甲醛脱附峰。吸附态甲酸脂在395K分解成CO_2和H_2。对反应机理作了探讨。     

电化学沉积Rh制备紫外拉曼活性基底

Rh在紫外激发区间有着较强的表面增加拉曼散射(SERS).用循环伏安法研究了RhCl3溶液中Rh3 在Au电极上的电化学还原行为,用恒电位阶跃法在Au基底上制备了Rh沉积层,并用场发射扫描电子显微镜、能谱及电化学方法对得到的沉积层进行了表征.结果表明,在所选择的电位下用电沉积方法能够在金表面得到均匀的Rh沉积层,该沉积层保持了金属Rh原有的电化学特性.采用电化学方法通过先粗糙Au电极再沉积Rh的策略,可以制备粗糙的Rh表面作为紫外SERS基底.拉曼光谱实验表明,以吡啶为探针分子,该基底具有很好紫外SERS活性.     

Epitaxial growth of ultrathin ZrO2（111） films on Pt（111）

Ordered epitaxial ZrO2 films were grown on Pt(111) and characterized by low energy electron diffraction (LEED), synchrotron radiation photoemission spectroscopy (SRPES) and X-ray photoelectron spectroscopy (XPS). The films were prepared by vapor deposition of zirconium in an O2 atmosphere followed by annealing under ultra high vacuum. At low coverages, the films grew as discontinuous two-dimentional islands with ordered structures. The size and structure of these islands were dependent on the coverage of Zr...     

AZ91D镁合金表面双层硅烷膜的制备及其性能研究

采用γ-氨丙基三乙氧基硅烷（KH-550）和双-1,2-[γ-三乙氧基硅丙基]-四硫化物（BTESPT）两种硅烷在AZ91D镁合金表面制备双层硅烷膜,通过正交试验选出了最佳制备工艺,即在KH-550硅烷中浸泡90 s,在BTESPT硅烷中浸泡5 min,再于80℃下固化90 min,得到550+BTESPT双层硅烷膜试样。通过接触角测试仪和动电位极化技术对试样进行润湿性和耐蚀性测试,通过扫描电子显微镜（SEM）、X射线能谱分析仪（EDS）对硅烷膜进行微观形貌和成分表征,通过X射线光电子能谱（XPS）对膜层元素的存在形式进行分析,结果表明：550+BTESPT双层硅烷膜表面接触角107.3°,表现为疏水性;在3.5%的NaCl溶液中,腐蚀电流密度为0.169 μA/cm²;硅烷膜表面形貌致密,主要有Mg、O、Si、S 4种元素组成;膜层中元素主要以Si-O-Si,Si-O-Mg,Si-O-X 3种形式存在。     

Sm(Ⅲ)-HP配合物与DNA的作用机制

 应用紫外-可见光谱法和荧光光谱法并以中性红(NR)作光谱探针研究了Sm(Ⅲ)HP配合物与DNA的作用机制。研究表明,血卟啉(HP)与Sm(Ⅲ)的配合比n_Sm(Ⅲ)∶n_HP = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合比n_Sm(Ⅲ)HP ∶ n_DNA = 1∶ 1,Sm(Ⅲ)HP配合物与DNA的结合常数K^θ_30℃ = 1.67×10⁴  L/mol。该过程为熵所驱动,其Δ _r H_m为4.86×10⁴ J/mol,Δ_r S_m为195.61 J/(mol·K),30 ℃时Δ_r G_m为－1.06×10⁴ J/mol。Scatchard法和探针法研究表明,Sm(Ⅲ)HP与DNA之间的结合方式主要是沟区作用。     

Influence of post-annealing on the properties of Ta-doped In<Subscript>2</Subscript>O<Subscript>3</Subscript> transparent conductive films

Ta-doped In₂O₃ transparent conductive oxide films were deposited on glass substrates using radio-frequency (RF) sputtering at 300°C. The influence of post-annealing on the structural, morphologic, electrical and optical properties of the films was investigated using X-ray diffraction, field emission scanning electron microscopy, Hall measurements and optical transmission spectroscopy. The obtained films were polycrystalline with a cubic structure and were preferentially oriented in the (222) crystallographic direction. The lowest resistivity, 5.1×10⁻⁴ Ω cm, was obtained in the film annealed at 500°C, which is half of that of the un-annealed film (9.9×10⁻⁴ Ω cm). The average optical transmittance of the films was over 90%. The optical bandgap was found to decrease with increasing annealing temperature.     

Microstructure evolution and phase transformation of traditional cast and spray-formed hypereutectic aluminium-silicon alloys induced by heat treatment

Microstructural evolution and phase transformation induced by different heat treatments of the hypereutectic aluminium-silicon alloy, Al-25Si-5Fe-3Cu (wt%, signed as 3C), fabricated by traditional cast (TC) and spray forming (SF) processes, were investigated by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy and X-ray diffraction techniques. The results show that Al₇Cu₂Fe phase can be formed and transformed in TC- and SF-3C alloys between 802–813 K and 800–815 K, respectively. The transformation from β-Al₅FeSi to δ-Al₄FeSi₂ phase via peritectic reaction can occur at around 858–870 K and 876–890 K in TC- and SF-3C alloys, respectively. The starting precipitation temperature of δ-Al₄FeSi₂ phase as the dominant Fe-bearing phase in the TC-3C alloy is 997 K and the exothermic peak about the peritectic transformation of δ-Al₄FeSi₂→β-Al₅FeSi is not detected in the present DSC experiments. Also, the mechanisms of the microstructural evolution and phase transformation are discussed.     

Rh(Ⅲ)对鲁米诺-H2O2-Cu(Ⅱ)化学发光抑制作用的研究及其测定

研究Rh(Ⅲ)对Lu-H     

氧化法在石英衬底上制备氧化钒薄膜及氧化过程和性能的研究

采用直流溅射法在石英衬底上沉积不同厚度的金属钒(V)膜,在空气氛围中进行不同温度热氧化处理获得性能最佳的退火温度和薄膜厚度。用X射线衍射仪(XRD),傅里叶变换红外光谱仪(FT-IR)和X射线光电子能谱仪分别研究了薄膜的晶体结构,红外透射性和表面组分。结果表明:厚度约为100 nm的金属钒膜在空气中370°C下氧化60 min制得VO2含量较高,相变温度45℃,热滞宽度约10℃,高低温光透过率变化41%的氧化钒薄膜。     

High quality p-type ZnO film growth by a simple method and its properties

P-type ZnO：N films have been grown successfully by chemical vapor deposition （CVD） using Zn4（OH）2（O2CCH3）6·2H2O as the solid source material and ZnNO3 as the doping source material. XPS, Hall-effect measurement and PL spectra were employed to analyze the structural, electrical and optical properties and study the influence of substrate temperature on the film. Results showed that with a lower substrate temperature, the film exhibited p-type conduction and its resistivity decreased when the substrete temperature increased. When the substrates temperature was 400℃, p-type ZnO films were obtained with carrier concentration of ＋5.127×10^17 cm^-3, resistivity of 0.04706 Ω· cm and Hall mobility of 259 cm^2/（V·s）; they still exhibited p-type conduction after a month. When the substrate temperature was too high, the film was transformed from p-type to n-type conduction.     

Directional solidification and physical properties measurements of the zinc-aluminum eutectic alloy

Zn-5wt% Al eutectic alloy was directionally solidified with different growth rates (5.32–250.0 μm/s) at a constant temperature gradient of 8.50 K/mm using a Bridgman-type growth apparatus. The values of eutectic spacing were measured from transverse sections of the samples. The dependences of the eutectic spacing and undercooling on growth rate are determined as λ=9.21V-0.53 and ΔT=0.0245V0.53, respectively. The results obtained in this work were compared with the Jackson-Hunt eutectic theory and the similar experimental results in the literature. Microhardness of directionally solidified samples was also measured by using a microhardness test device. The dependency of the microhardness on growth rate is found as Hv=115.64V0.13. Afterwards, the electrical resistivity (r) of the casting alloy changes from 40×10-9 to 108×10-9 Ω·m with the temperature rising in the range of 300–630 K. The enthalpy of fusion (ΔH) and specific heat (C_p) for the Zn-Al eutectic alloy are calculated to be 113.37 J/g and 0.309 J/(g·K), respectively by means of differential scanning calorimetry (DSC) from heating trace during the transformation from liquid to solid.     

Hydrogen storage performances of the as-milled REMg11Ni (RE = Sm, Y) alloys catalyzed by CeO2

The addition of catalysts and rare earth elements is considered to be very effective methods to enhance the hydrogenation/dehydrogenation properties of Mg and Mg-based hydrides. In this paper, the REMg11 Ni+ 5 wt%CeO_2(RE = Sm, Y)(named REMg11 Ni-5 CeO_2(RE = Sm, Y)) alloys were fabricated through ball milling. The phase composition and structure of the as-milled alloys were investigated in detail. The isothermal hydrogen storage thermodynamics and kinetics of the as-milled alloys were measured by using an automatically Sievert apparatus. Non-isothermal dehydrogenation performance of the alloys was investigated by thermogravimetry(TG) and differential scanning calorimetry(DSC) at different heating rates. The results revealed that all the asmilled alloys were the nanocrystalline and amorphous structure. The RE = Y alloy had a faster hydriding rate and a lower onset hydrogen desorption temperature than the RE = Sm alloy. The superior property of the RE= Y alloy depended on the decrease of the dehydrogenation activation energy. By means of the measurement of Pressure-Composition-Isotherm(P-C-T) curves, the thermodynamic parameters of the REMg11 Ni-5 CeO_2(RE =Sm, Y) alloys were calculated, and the dehydrogenation enthalpy change was 74.86 k J/mol for the RE = Sm alloy and 73.75 k J/mol for the RE = Y alloy, respectively.     

中温固体氧化物燃料电池复合阴极材料的性能

利用甘氨酸法合成复合材料La0.6Sr0.4Co0.2Fe0.8O3-δ-Ce0.8Ca0.2O1.9,该材料作为中温固体氧化物燃料电池的阴极材料被研究,XRD、SEM-EDS、O2-TPD等被用于检测材料的各种性能.得到优化的合成温度是1 100 ℃,在该温度条件下晶粒的平均粒径为400 nm,而且所合成的样品的元素比与所设计的化学计量比吻合.LSCF70-CDC的电导率在700℃温度下最高.氧的解吸结果表明结构中存在着几种不同类型的氧.     

TiO2薄膜折射率的调控方法

采用电子束蒸发技术及其辅助工艺制备了TiO2薄膜,利用X射线衍射(XRD)、X射线光电子能谱(XPS)和原子力显微镜(AFM)对薄膜的组织结构进行了表征,采用紫外可见分光光度计研究了TiO2薄膜的折射率变化.结果表明:传统电子束蒸发镀制的TiO2薄膜的折射率低于块体值,通过调节氧气压、沉积速率和衬底温度可在1.97～2...     

Investigation of the Ce-Mn conversion coating on 6063 aluminium alloy

In this paper, the sustainable Ce-Mn chemical conversion coating was fabricated on 6063 aluminium alloy by means of Ce(NO₃)₃ and KMnO4 as the inhibitors and NaF as the accelerator. The morphologies, composition and valence state of the coating were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The results indicated that the Ce-Mn conversion coating was formed. The anticorrosion of the coating was evaluated in 3.5 wt.% NaCl aqueous solution at room temperature by using polarization curve and electrochemical impedance spectroscopy (EIS). It indicated that the treated surface presented better anticorrosion behavior in chloride media than on the original material surface. The corrosion resistance of Ce-Mn conversion coating was about equal to the trivalent chromium conversion coating.     

镍基合金CMSX-4在3.5wt.% NaCl溶液中的腐蚀行为

研究二代镍基合金CMSX-4在质量分数为3.5% NaCl溶液中的腐蚀行为,对该类合金在海洋性环境条件下的应用具有深远意义。通过动电位极化方法研究室温条件下镍基合金CMSX-4在3.5 wt.% NaCl溶液中的电化学行为,利用扫描电子显微镜（SEM）、能谱分析仪（EDS）和X射线光电子能谱仪（XPS）对合金表面阳极腐蚀产物进行微观形貌观察及成分分析。研究表明,CMSX-4合金具有一定的钝化能力,钝化区间比较宽广;在镍基合金CMSX-4表面上形成的腐蚀产物可大致分为两层,表层主要由Ni （OH）₂、Cr （OH）₃、Co （OH）₂和Al （OH）₃等氢氧化物组成,内层主要分布着NiO、Al₂O₃、CoO、Cr₂O₃和CrO₃等氧化物及组成合金基体的各种金属;由Ni （OH）₂和Cr （OH）₃等氢氧化物组成的腐蚀产物膜外层能够在腐蚀介质和金属之间产生较好的屏蔽效果;构成腐蚀产物膜内层的NiO、Al₂O₃、Cr₂O₃和CrO₃等氧化物有利于产物膜内层与外层之间建立一定的空间电荷区,对稳定腐蚀产物内层有很大帮助。研究表明CMSX-4合金在海洋性环境中具有一定的耐蚀性能。     

Graphite-polypyrrole coated 316L stainless steel as bipolar plates for proton exchange membrane fuel cells

316L stainless steel (SS 316L) is quite attractive as bipolar plates in proton exchange membrane fuel cells (PEMFC). In this study, graphite-polypyrrole was coated on SS 316L by the method of cyclic voltammetry. The surface morphology and chemical composition of the graphite-polypyrrole composite coating were investigated by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A simulated working environment of PEMFC was applied for testing the corrosion properties of graphite-polypyrrole coated SS 316L. The current densities in the simulated PEMFC anode and cathode conditions are around 3×10-9 and 9×10-5 A·cm-2, respectively. In addition, the interfacial contact resistance (ICR) was also investigated. The ICR value of graphite-polypyrrole coated SS 316L is much lower than that of bare SS 316L. Therefore, graphite-polypyrrole coated SS 316L indicates a great potential for the application in PEMFC.     

Catalyst enhanced chemical vapor deposition of nano-particle nickel films on teflon surface

Films formed with nanosized nickel particles on teflon surface were prepared by means of catalyst enhanced chemical vapor deposition (CECVD) with Ni(dmg)₂, Ni(acac)₂, Ni(hfac)₂, Ni(TMHD)₂, and Ni(cp)₂ as precursors, and complexes Pd(hfac)₂, PdCl₂ and Pd(η ³-2-methylallyl)acac as catalyst under carrier gas (H₂). The film growth rate depends on the precursors and substrate temperature. The chemical value, purity and surface morphology of the Ni particle films were characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The films obtained were shiny with silvery color, and consisted of grains with a particle size of 50–140 nm. The Ni was metallic of which the purity was about 90%–95% from XPS analysis. SEM micrograph showed that the film had good morphology.