阳极氧化Ti-6Al-4V合金表面TiO2多孔膜的制备及研究

在一定浓度的H₂SO₄溶液中对Ti-6Al-4V合金表面进行阳极氧化处理,通过改变阳极氧化处理的电压、氧化时间和电解液浓度,研究了预处理工艺参数对钛合金表面形貌、物相、润湿性及粗糙度的影响.试验结果表明：钛合金经过阳极氧化处理后,表面出现了二氧化钛（TiO₂）纳米多孔结构,多孔氧化膜由锐钛矿型和金红石型TiO₂组成;在0.5 mol·L^-1 H₂SO₄溶液中,随着阳极氧化电压的增加,多孔膜的孔径逐渐增大,基体表面与模拟体液（SBF）的接触角明显降低,经120 V氧化处理的试样表面接触角由预处理前的52.8°降至16.9°左右,具有良好的润湿性;并且试样表面的粗糙度明显增加,在电压为120 V时粗糙度达到0.56 μm.在电压120 V时,随着阳极氧化时间或电解液浓度的增加,TiO₂多孔膜的含量和孔径尺寸逐渐增大,试样表面的润湿性和粗糙度也不断增加,在氧化时间10 min或电解液浓度0.5 mol·L^-1时达到最大,氧化时间大于10 min或电解液浓度高于0.5 mol·L^-1时,试样表面出现裂纹,多孔结构被破坏.     

乙二胺四乙酸二钠对钛合金表面羟基磷灰石涂层的影响

采用水热电化学方法在Ti6Al4V基体表面沉积羟基磷灰石（HA）涂层,研究乙二胺四乙酸二钠（EDTA-2Na）对HA涂层的物相组成、形貌、结合强度及生物相容性的影响.结果表明,电解液中无论添加EDTA-2Na与否,水热电化学沉积得到的仍为结晶度较高、生物相容性较好的HA涂层;不同的是,与不添加EDTA-2Na的涂层相比,添加EDTA-2Na后沉积得到的HA晶体形貌发生较大改变.随着EDTA-2Na浓度的增加,HA晶体从长薄片状到花瓣状以及纤维带状;HA涂层（002）晶面衍射峰强度随着EDTA-2Na浓度的增加逐渐减弱,涂层厚度也随之减小;HA涂层与基体的结合强度,随EDTA-2Na浓度的增加先增大后减小,在浓度为7.5×10^-4 mol·L^-1时达到最大值16.8 MPa.     

磁控溅射表面镀膜对Nd2Fe14B稀土永磁体抗腐蚀性能的影响

在Nd₂Fe₁₄B稀土永磁体基体表面,采用磁控溅射（直流+射频）技术制备了Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜。并通过中性盐雾试验、腐蚀失重计算、电化学腐蚀试验、金相观察等方式,对比研究了不同表面处理对Nd₂Fe₁₄B稀土永磁体基体抗腐蚀性能的影响,并构建了腐蚀模型。研究发现：Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜均有效地提高了Nd₂Fe₁₄B稀土永磁体基体耐中性盐雾腐蚀和电化学腐蚀的能力;Ti/Al/Ni三元合金薄膜较Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜有更优良的综合耐腐蚀性能,其磁控溅射工艺参数为：Ar流量60 sccm,基片温度常温,Ni,Al,Ti的溅射功率都为250 W,基片转速20 r·min^-1,镀膜均速0.3 nm·s^-1,总计溅射时间1 h。     

HA/YSZ/Ti6Al4V生物复合材料的制备与界面特性

采用磁控溅射法制备出HA／YSZ／Ti6Al4V生物复合材料,利用X-射线衍射仪（XRD）、扫描电镜（SEM）和能谱分析（EDXA）研究复合涂层的相组成、表面微观形貌和界面微观形貌,并用划痕仪测定复合涂层与基体的界面结合力．结果表明：溅射的复合涂层中主要含有HA、ZrO2和Y2O3物相,此外还有少量的TCP和CaO相;该复合涂层表面凹凸不平,呈现网状微孔结构,其孔隙直径约为0．5～2μm,孔隙面积占薄膜表面积的30％～40％．划痕试验表明,复合涂层与Ti6Al4V基体结合力约为80N．复合涂层拉伸试样横断面分析显示,在涂层与基体界面处无裂纹,界面处存在Ti6Al4V基体成分Ti与复合涂层成分Ca、P问互扩散的扩散层,该扩散层厚度为0．5～1．5μm,复合涂层界面的结合机制为机械齿合和扩散结合．     

电弧喷涂铝涂层阳极氧化后表面-截面结构分析

采用电弧喷涂工艺在S355钢表面制备Al涂层,并对其进行阳极氧化处理,通过SEM,EDS和XRD等技术分析试样表面-截面形貌、化学元素分布和物相组成,探讨氧化膜-Al涂层-基体的结合机理。实验结果表明:阳极氧化膜中Al与O出现富集现象,以Al2_O_3形式存在;Al与O原子在氧化膜中为高浓度分布,构成氧化膜-Al涂层-基体的复合防腐蚀体系;Al涂层为富Al层,原子含量较高,而基体中Fe原子在界面处发生扩散现象;Al涂层中少量Al原子扩散进入基体,在界面处与Fe反应生成Fe-Al化合物,提高电弧喷涂Al涂层的结合强度。     

脉冲频率及占空比对3D打印Ti6Al4V合金表面生物活性涂层的影响

采用微弧氧化法,在恒定电压下,使用不同的脉冲频率及脉冲占空比,在3D打印Ti6Al4V合金表面制备生物活性涂层。利用扫描电子显微镜、能谱仪、电化学工作站、涡流膜厚仪、Image J软件和划痕仪等对涂层进行结构、性能以及微观形貌表征,研究脉冲频率和脉冲占空比对涂层的影响。结果表明：随着脉冲频率的增加,涂层的平均孔径、Ca/P比、表面粗糙度和厚度均逐渐减小,孔隙率变化不明显;耐腐蚀性先得到改善后变差;涂层与基体的结合力逐渐变大。随着脉冲占空比增大,涂层的平均孔径、孔隙率、Ca/P比、厚度逐渐变大;耐腐蚀性能呈现先好后差的趋势;涂层与基体的结合力逐渐变弱。     

钛金属表面原位自生K2(Ti8O17)/ TiO2复合生物陶瓷涂层的制备及其生物相容性

采用电化学原位自生方法在钛基体表面成功制备出了K2(Ti₈O₁₇)/ TiO₂复合生物陶瓷涂层，并对涂层的表面形貌、微观结构及相组成等进行了观察分析.通过模拟体液培养对其生物活性进行了评估.结果表明，所制备的K2(Ti₈O₁₇)/ TiO₂复合陶瓷涂层具有良好的生物相容性和生物活性.     

混合微波退火改性Cd2SnO4光阳极用于光电催化水氧化性能的研究

首次采用混合微波退火法制备了改性Cd₂SnO₄光阳极,有效地提高了Cd₂SnO₄光阳极的光电催化水氧化性能。采用扫描电子显微镜(scanning electron microscope, SEM)、X射线衍射仪(X-ray diffractometer, XRD)、拉曼光谱(Raman spectroscopy, Raman)、比表面积分析仪(Brunauer-Emmett-Teller surface area, BET)和稳态荧光光谱仪(photoluminescence spectroscopy, PL)等对混合微波退火改性前后的Cd₂SnO₄光阳极的表面形貌、晶体结构和组成进行了表征。性能测试结果表明,在1.70 V可逆氢电极(reversible hydrogen electrode, RHE)电压下,混合微波退火改性的Cd₂SnO₄光阳极光电流密度为12 μA/cm²,与传统热烧结制备的Cd₂SnO₄光阳极相比,其性能提升了3倍。根据电化学阻抗谱(electrochemical impedance spectra, EIS)和PL光谱测试结果可知,改性的Cd₂SnO₄光阳极的光电催化水氧化性能的提升可以归因于多孔结构导致的光生电子空穴分离速率的提升。     

电解液浓度和沉积时间对Zn涂层表面形貌影响的研究

采用阳极氧化法在纯钛基体表面制备一层TiO₂纳米管（TiO₂ nanotubes,TNs）,随后采用电化学沉积法在ZnCl₂溶液中于TNs上制备了Zn涂层。采用扫描电子显微镜（scanning electron microscopy,SEM）、能量色散X射线光谱仪（energy dispersive X-ray spectrometer,EDS）和X射线衍射仪（X-ray diffraction,XRD）对涂层的表面和截面形貌、元素含量和相组成进行表征。结果表明：TNs长度为1.5 μm,Zn涂层厚度为2 μm;在沉积的过程中,Zn涂层首先沿着TNs的管壁生长,逐渐覆盖TNs,然后形成球状晶体,最后形成白色颗粒堆叠在TNs上;电解液浓度的增加提高了涂层生长速度,沉积时间的延长使晶体有充足的时间长大;涂层中Zn是以单质形式存在,白色颗粒也主要为Zn单质。     

Al/Ti对Cu-10Ni合金耐冲刷腐蚀性能的影响

研究微合金化对Cu-10Ni合金耐3.5%NaCl溶液冲刷腐蚀的影响。使用中频真空熔炼炉熔炼Cu-10Ni-1Fe-1Mn-X（X=0.2Al或0.2Ti）合金,使用相同的热处理及冷变形工艺制备样品后与Cu-10Ni合金一起进行冲刷腐蚀实验。通过扫描电子显微镜（scanning electron microscope,SEM）、X射线衍射仪（X-ray diffractometer,XRD）、电化学腐蚀、电化学阻抗谱（electrochemical impedance spectroscopy,EIS）、X射线光电子能谱仪（X-ray photoelectron spectrometer,XPS）、质量损失测试等对样品进行分析表征。结果表明：加入0.2Al/0.2Ti后的Cu-10Ni合金的耐冲刷腐蚀能力得到提高。这是由于在Cu-10Ni-0.2Al合金及Cu-10Ni-0.2Ti合金表面耐腐蚀膜中分别含有Al₂O₃、TiO₂,提高了样品的耐冲刷腐蚀能力;Cu-10Ni-0.2Ti合金耐冲刷腐蚀能力略强于Cu-10Ni-0.2Al合金的,这是因为Cu-10Ni-0.2Al合金在Cl^?富集的环境中易吸收Cl^?,从而导致膜层有一定的裂纹。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that