Investigation of working pressure on the surface roughness controlling technology of glow discharge polymer films based on the diagnosed plasma

The effects of working pressure on the component, surface morphology, surface roughness, and deposition rate of glow discharge polymer （GDP） films by a trans-2-butene/hydrogen gas mixture were investigated based on plasma characteristics diagnosis. The composition and ion energy distributions of a multi-carbon （CaHs/H2） plasma mixture at different working pressures were diagnosed by an energy-resolved mass spectrometer （MS） during the GDP film deposition process. The Fourier transform infrared spectroscopy （FT-IR）, field emission scanning electron microscope （SEM） and white-fight interferometer （WLI） results were obtained to investigate the structure, morphology and roughness characterization of the deposited films, respectively. It was found that the degree of ionization of the C4H8/H2 plasma reduces with an increase in the working pressure. At a low working pressure, the C-H fragments exhibited small-mass and high ion energy in plasma. In this case, the film had a low CH3/CH2 ratio, and displayed a smooth surface without any holes, cracks or asperities. While the working pressure increased to 15 Pa, the largest number of large-mass fragments led to the deposition rate reaching a maximum of 2.11 #m h-1, and to hole defects on the film surface. However, continuing to increase the working pressure, the film surface became smooth again, and the interface between clusters became inconspicuous without etching pits.

THE EFFECT OF WOOD SURFACE ROUGHNESS OF DIFFERENT SPECIES OF TREES ON WOOD COLOR IN WORKING OPERATION

The multinomial wood surface roughness parameters and wood color parameters of 5 kinds of species of trees were measured in working operation by the stylus surface roughness meter and colorimeter, and the measurement results were compared. The results indicated: The variations of wood surface roughness had the effect on the wood color of some kinds of species of trees on working operation, with the surface roughness decreasing, the brightness and luminance exponent increased, the hue angle increased lightly, but the variation of color saturation was different to the different wood color hue of species of trees.

Influence of Different Surface Treatments of H13 Hot Work Die Steel on Its Thermal Fatigue Behaviors

Thermal fatigue checking is the general failure of hot work die steels, which is relative with the structures and properties of the steels and the stress alternated during the employment. The Uddeholm test method on thermal fatigue is used to compare the behaviors of different samples, which are treated with plasma nitriding、plasma sulfur carbon nitriding、boronizing or not treated. The results show that the nitriding improves the thermal fatigue property of the tool steel, while the plasma sulfur carbon nitriding and the boronizing impair the property. The mechanisms are induced as follows. By increasing the hardness and changing the stress distribution in the surface layer, surface treatment can decrease the plastic deformation and the tensile stress during the cycling. Therefore, the generation and growth of the cracks are restrained. On the other hand, as results of surface treating, in the surface layer the toughness declines and the expanding coefficient ascendes; the latter change caused the strengthening of the tensile and compressive stress during the cycling. Thus the resistance to thermal fatigue is weakened. Whether or not the surface treatment is favor to thermal fatigue of tool steels relies on which factor is dominant.

SURFACE SEGREGATION IN Mo-La ALLOY WIRE

The surface segregation in Mo-4wt-% La alloy wire has been studied by using Auger elec- tron spectroscopy.The process of the segregation is that the La atoms diffuse from the grain boundaries to surface.The experimental results were analysed by kinetics of grain boundary diffusion.The diffusion activation energy E_(?)=1.6 eV was obtained.

Comparative study of adsorption characteristics of Cs on the GaN(0001) and GaN(000) surfaces

The adsorption characteristics of Cs on GaN （0001） and GaN （0001） surfaces with a coverage from 1/4 to 1 monolayer have been investigated using the density functional theory with a plane-wave uttrasoft pseudopotential method based on first-principles calculations. The results show that the most stable position of the Cs adatom on the GaN （0001） surface is at the N-bridge site for 1/4 monolayer coverage. As the coverage of Cs atoms at the N-bridge site is increased, the adsorption energy reduces. As the Cs atoms achieve saturation, the adsorption is no longer stable when the coverage is 3/4 monolayer. The work function achieves its minimum value when the Cs adatom coverage is 2/4 monolayer, and then rises with Cs atomic coverage. The most stable position of Cs adatoms on the GaN （000i） surface is at H3 site for 1/4 monolayer coverage. As the Cs atomic coverage at H3 site is increased, the adsorption energy reduces, and the adsorption is still stable when the Cs adatom coverage is 1 monolayer. The work function reduces persistently, and does not rise with the increase of Cs coverage.

Chromizing treatment of the surface-nanocrystallized AISI H13 steel and the improved wear resistance

A hot-working AISI H13 tool steel was subjected to a combined process consisting of surface nanocrystallization(SNC)and chromizing treatment successively.The composition,microstructure,hardness and wear resistance of the chromized layer were characterized by using the scanning and transmission electron microscopy,a nano-indenter and a tribo-meter.It was shown that a continuous chromized layer of approximately 30 μm in thickness was formed on the SNC specimen after a dual chromizing treatment at both 600℃ and 1050℃ consecutively,as thick as about 3 times of that on the coarse-grained specimen after the same chromizing treatment.In addition,the wear resistance of the SNC-chromized specimen was enhanced significantly,due to a smaller grain size and a higher hardness,as well as smoother gradient variations of the microstructure,composition and hardness across a greater depth in the formed chromized surface layer.

A DFT Calculation of Nb and Ta (001) Surface Properties

First principle calculations are performed using the super cell method with pseudopotentials and plane waves based on the Density Functional Theory (DFT) for the surface structural properties at T = 0 K. Thin slabs of 7 - 13 atomic layers of the clean Nb and Ta (001) surfaces are considered and relaxations, surface energies, and work functions of the fully relaxed slabs are presented. Consistent results are obtained with the Generalized Gradient Approximation (GGA) and the Local Density Approximation (LDA) for the exchange-correlation functional and they compare well with experimental and other theoretical works.

Density Functional Study of the Cluster Model of SnO₂(110) Surface Modified by Benzoic Acids

The properties of the modified surface of SnO2(110) with benzoic acid (Y-C6H4-COOH: Y is para position relative to -COOH group) derivatives were investigated using density functional theory. Zehner et al. mentioned that the modification of surface dipole moment made it possible to tune the work function of the system. The experiment of Ganzorig et al. showed that there was a linear relationship between the dipole moment of the binding molecule and the work function change of the system using the modified surface of indium-tin oxide (ITO) with some benzoic acid derivatives. To elucidate the relation between the dipole moment of the molecule and the work function change, we investigated the modified surface of SnO2(110) using Sn7O14 cluster model which was embedded in the fixed point charges. On the modification of the surface, benzoic acid derivatives were bound to SnO2 surface. By changing the terminal group of benzoic acid with H, Cl, F, CF3 and CCl3, the work function changed and the dipole moment of the binding molecules of the modified SnO2(110) were evaluated. The results showed that there was a linear relationship between the dipole moment of the binding molecules and the work function changed. From this relation, the average value of the dipole moments of Sn-OOC linkage at the surface was also evaluated.

Effect of ceramic work rolls on surface roughness of rolled SUS304 ultra-thin strips

Surface morphology and roughness are important parameters of surface quality of cold-rolled ultra-thin strip steel.In order to study the effect of Si_(3)N_(4) ceramic work rolls on the surface roughness of SUS304 ultra-thin strip,ABAQUS finite element model calculation,3D laser profilometry,and other methods were adopted based on the physical characteristics of Si_(3)N_(4) ceramic roll and 9Cr2MoV steel roll,like anti-flattening performance and oil wettability.The surface morphology and roughness of SUS304 ultra-thin strip rolled by different material work rolls under oil lubrication conditions were measured.The results showed that under the rolling force of 10 kN,the maximum flattening amount of Si_(3)N_(4) ceramic roll was reduced by 35.14%compared to that of 9Cr2MoV steel roll.The reduction rate of SUS304 ultra-thin strip rolled by ceramic roll was 34.19%,while that rolled by steel roll was only 22%;Si_(3)N_(4) ceramic roll can further increase the number of alternating convex peaks and concave valleys in the rolled thin strip,reduce the profile steepness,reduce surface roughness,and enhance the planarization effect of surface micro-convex bodies,with improving surface quality and surface glossiness.Finally,the mechanism of Si_(3)N_(4) ceramic roll significantly improving the surface roughness of rolled SUS304 ultra-thin strip was proposed.

基于Solid Works的螺旋面零件三维实体造型

根据螺旋面形成原理和结构特点,借助于Solid Works三维设计软件这个操作平台,通过典型实例,利用Solid Works软件中扫描等相关功能,提出了一种螺旋面零件三维造型通用的设计方法,并对螺旋面的一些渐变情形提出了具体的解决办法。此方法具有造型速度快、精度高的优点,为机械产品的快速设计奠定了基础。

Prediction and Analysis on Oxidation of H13 Hot Work Steel

The understanding of oxidation behaviors on H13 steel was helpful to improve the service life and performance of hot work moulds and dies. Thermal-Calc Software was performed to calculate the oxidation phases on H13 steel along with different partial oxygen pressures in the interesting temperature range of 500-700 ℃. In this range H13 steel samples were treated respectively in different atmosphere including flowing water vapor （0.2 MPa）, normal pressure air （0.1 MPa） and low pressure air （0. 001 MPa）. The different oxidation films were detected with optical microscopy and X-ray diffraction. The microstructures and phase constitutions of the films formed in low pressure air were similar to those of the films formed in water vapor, and obviously different to those of the films formed in normal pressure air. The oxidation mechanisms of H13 steel in different atmosphere were also discussed.

面向反求工程的Solid Works曲面建模

介绍了曲面模型的特点及反求工程中曲面构造的方案;提出了基于Solid Works的2种曲面反求建模策略,并对2种策略下曲面建模的原理、方法及区别进行了详细的研究;同时还介绍了Solid Works的网格处理功能与作用。

Work Function Enhancement of Indium Tin Oxide via Oxygen Plasma Immersion Ion Implantation

Indium tin oxide （ITO） transparent conducting film was treated with oxygen plasma immersion ion implantation （PIII）. X-ray photoelectron spectroscopy （XPS） was employed to characterize the effect. The results suggested that the oxygen content in the surface was increased and maintained for more than 50 h compared with traditional plasma-treated samples. Meanwhile, the work function of ITO estimated by comparing the peak shift in the XPS diagram suggested a corresponding increase by more than 1 eV.

Influence of plasma peening on oxidation of H13 hot work steel in water vapor

The surface oxidation films on H13 steel samples, obtained by different oxidation processes were observed by optical microscope. It is shown that the oxidation speed of H13 steel is increased remarkably due to the surface modification of plasma peening. Further researches were made by XRD, SEM and EDS. The activation of H13 surface caused by plasma peening and the subsequent higher oxygen diffusion rate into the steel seem to be the main reasons of higher oxidation speed. The nitride layer, generally formed on the steel surface under plasma nitriding process, can be substituted by oxide in subsequent oxidation process, which can reduce the risk of heat cracking in some hot work applications. Therefore, the plasma nitriding plus oxidation process is a proper choice for some hot work dies, which demands high hardness to avoid indentation as well as high toughness to avoid cracks.

工作−家庭冲突与中小学教师工作繁荣的关系:基于多项式回归与响应面分析的探索

使用问卷法对2876名中小学教师进行调查,探讨工作−家庭冲突的双向对比情况与中小学教师工作繁荣的关系,以及心理资本在二者关系中的作用机制。结果发现:(1)当工作干扰家庭与家庭干扰工作水平一致时,与“低−低”干扰相比,“高−高”干扰的教师具有更低的工作繁荣水平和心理资本水平;(2)当工作干扰家庭与家庭干扰工作水平不一致时,与“高−低”干扰相比,“低−高”干扰的教师具有更低的工作繁荣水平和心理资本水平;(3)教师的心理资本在其工作−家庭冲突与工作繁荣的关系之间起部分中介作用。

退火处理对CVD生长石墨烯薄膜功函数的影响

通过退火处理去除了石墨烯薄膜上的吸附气体和杂质,改变了石墨烯表面吸附情况.利用原子力显微镜和开尔文扫描探针显微镜,对退火处理前后的石墨烯薄膜表面进行了原位扫描,分别得到其退火前、后的表面形貌和表面接触电势差图.根据表面接触电势差测量结果进一步计算其功函数,并对退火处理导致的功函数变化机理进行分析.结果表明:退火处理使得石墨烯薄膜与SiO_(2)衬底间的水分子层逸出,从而导致石墨烯薄膜与SiO_(2)衬底间距减小,降低了石墨烯薄膜的P型掺杂水平,使得费米能级上升、石墨烯薄膜功函数减小.

手过头静态作业的上肢肌肉疲劳特性研究

为探究手过头不同高度下静态作业的上肢肌肉疲劳特性,通过实验设计采集了被试的表面肌电信号(surface electromyography,sEMG)及基于Borg CR-10量表的主观疲劳状态,研究了sEMG的时域与频域特征处理方法,并利用多分类支持向量机(support vector machine,SVM)识别肌肉疲劳状态。通过对肌肉贡献率、主客观肌肉疲劳特征的相关性、不同高度下的肌肉疲劳累积排序及肌肉疲劳分类识别进行分析,结果表明:肌肉平均贡献率超过10%的肌肉为肱二头肌、三角肌与斜方肌,且其累积贡献率超过70%;对疲劳累积程度在3个高度下排序,肱二头肌和斜方肌为H_(3)>H_(2)>H_(1),三角肌为H_(2)>H_(3)>H_(1);随着手过头静态作业时间增加,上肢肌肉疲劳逐渐积累,时域特征值增加、频域特征值减小且其变化具有一致性;多分类SVM对手过头静态作业中的上肢肌肉疲劳识别准确率大于90%。

低渗致密气藏防水锁剂配方性能评价

基于吐哈油田低渗致密气藏,研发一种新型气藏防水锁剂GY-HE85,对其界面张力、表面张力和润湿性等基本性能进行研究,并分析了岩心渗透率恢复效果。实验结果表明,氟碳表面活性剂与碳氢表面活性剂复配后,碳氢表面活性剂除降低界面张力的作用之外,由于异电性亲水基之间强烈的静电吸引作用,表面活性剂分子在更低含量即可达到饱和吸附,还可降低表面活性剂的使用量。防水锁剂GY-HE85含量为0.1%~0.5%(w)的溶液时,表面张力为20.23~47.52 mN/m,随着溶液含量减小,拟黏附功逐渐降低,降幅呈“先快后慢”趋势,防水锁剂GY-HE85溶液优选含量为0.3%(w)。防水锁剂GY-HE85溶液具有较好的抗吸附性能,岩心渗透率恢复率在86.44%~91.20%,较好地预防了致密气藏储层“水锁”现象的发生。

超声滚压对DC53钢表面性能的影响

为了改善DC53冷作模具钢的表面性能,使用扫描电子显微镜、激光光谱共聚焦显微镜、显微硬度计、球-盘摩擦磨损试验机等设备分析了超声表面滚压加工工艺(USRP)的静压力、滚压道次、振幅、进给量对DC53冷作模具钢表面粗糙度、显微硬度、摩擦因数和磨损的影响规律。结果表明:与未处理DC53模具钢相比,USRP处理后DC53冷作模具钢表面产生了塑性变形,表面粗糙度由5.570μm最低可降为1.067μm,且在DC53冷作模具钢表面产生了晶粒细化现象,引入了梯度硬化层,表面硬度由基体的720 HV最大可提升为818.6 HV,硬化层深度最大可达300μm。摩擦因数降低,磨痕宽度减小,耐磨性能提高。通过极差分析法获得了对粗糙度、显微硬度、摩擦因数影响最大的工艺参数依次为进给量、滚压道次、静压力。通过灰色关联度分析法获得了工艺参数对表面性能的影响次序为静压力>进给量>滚压道次>振幅,最佳工艺参数组合为静压力400 N,滚压道次4次,振幅12μm,进给量0.05 mm。

表面圆形凹坑微织构对DC53模具钢的摩擦学性能影响

为了探究微织构对DC53冷作模具钢表面摩擦学性能的影响,基于有限元法研究了模具钢表面圆形凹坑微织构的最优深度,采用飞秒激光加工了不同面密度的圆形凹坑微织构模具钢试样,并通过开展摩擦磨损实验研究了不同润滑状态下面密度对模具钢摩擦学性能的影响规律。结果表明,DC53冷作模具钢表面的圆形凹坑微织构在直径为Φ140μm,织构深度为50μm时表现出最大油膜承载力与最小摩擦因数;随着圆形凹坑微织构面密度的增加,充分润滑时模具钢表面的摩擦因数先减小后增大,面密度为20%时平均摩擦因数最小,相较于无织构模具钢降低了51.35%;少油润滑与干摩擦时,模具钢表面摩擦因数随着面密度的增加逐渐降低;面密度为30%时,模具钢表面平均摩擦因数最小,较无织构模具钢分别降低了35.84%与15.02%。微织构的存在提升了模具钢表面不同润滑状态下的减摩性能;充分润滑时效果最好,干摩擦时也明显改善了模具钢表面的黏着磨损。