THE IMPROVEMENT OF ELECTRON FIELD EMISSION FROM AMORPHOUS CARBON FILMS DUE TO HYDROGEN PLASMA CHEMICAL ANNEALING EFFECT

1. IntroductionHydrogenated amorphous carbon (a-C:H) films have been attracted much attentionsince these materials are powerful candidate fOr the next generation of high-perfOrmanceelectronic devices and other vacuum electronic de.ices[l--3]. For cold cathode operationin flat panel display, a large area electron emission with a low operation voltage, stableand high currellt density is required. However, compared with diamond materials, theturn-on electron field of amorphous carbon is still h…     

磁场对中碳钢滑动摩擦磨损的影响

研究了钕铁硼永磁体磁场对中碳钢摩擦磨损的影响,当磁场的４５ｍＴ时,环和块的磨损量分别下降约５０％和６０％,进一步增加磁场磨损则缓慢下降,至１９３ｍＴ时,环和块平均降低达７０％,摩擦系数降低约３０％,分析表明,磁场导致氧化磨损的比例增加是磨损降低的主要原因。     

锂盐碳阳极的可湿性与临界电流密度研究

含有锂盐的碳阳极的可湿性和发生阳极效应的临界电流密度值明显提高，可以防范阳极效应的发生，文中讨论了锂盐的作用机理。     

HIGHLY DISPERSED MULTI-WALLED CARBON NANOTUBES IN WATER／ETHANOL AND ITS APPLICATION FOR PVA COMPOSITE

Two carboxylation processes were carried out to modify multi-walled carbon nanotube bundles (m-MWNTs). The results showed that both of the m-MWNTs could be highly dispersed in water with the concentration up to 25 and 15mg/mL in ethanol without obvious deposition or conglomeration over 6 months. FTIR, Raman, TGA and TEM characterizations of the m-MWNTs showed that hydroxyl and carboxyl groups have been attached with MWNTs, and that the nanotube structure was only damaged a little after modification treatments in mixed acids over 24h. Above prepared nanotube suspensions in water were successfully used as a filler of thermoplastic PVA composite to enhance its electrical conductivity. The results showed that the addition of m-MWNTs greatly improved the conductivity and the threshold of mass fraction was about 5wt%. The results also proved that purification process was not needed because of high ouritv of the raw MWNTs oreoared in our group.     

INFLUENCES OF MODIFIERS ON SURFACE PROPERTIES OF WHITE CARBON BLACK AND MECHANICAL PROPERTIES OF SILICONE RUBBER

１．ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｉｔｅｃａｒｂｏｎｂｌａｃｋｉｓａｎｉｍｐｏｒｔａｎｔｐｏｗｄｅｒｔｙｐｅｍａｔｅｒｉａｌ．Ｔｈｅｏｘｇｏｓｉｌａｎｅｓｔｒｕｃｔｕｒｅａｎｄｔｈｅｈｙｄｒｏｘｙｄｉｓｔｒｉｂｕｔｅｄｏｎｔｈｅｓｕｒｆａｃｅｏｆｗｈｉｔｅｃａｒｂｏｎｂｌａｃｋ,ａｓａｎｅｎｈｅｎｃｅｍｅｎｔｆｉｌｌｅｒｏｆｈｉｇｈｍｏｌｅｃｕｌｅｍａｔｅｒｉａｌ（ｓｕｃｈａｓｒｕｂｂｅｒａｎｄｐｌａｓｔｉｃ）,ｃａｎｉｎｆｌｕｅｎｃｅｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｃｏｍｐｏｓｉｔｅｍａｔｅｒ…     

电子束焊功率密度分布与温度场关系的研究

采用大型有限元ＡＤＩＮＡＴ程序，对电子束焊三种功率密度分布模型进行了分析，结果表明，三角形模型和高斯模型计算温度与焊接接头实际温度存在偏差，按实际温度改进高斯模型使之相吻合。     

THE INFLUENCES OF SOLUTION PH AND CURRENT DENSITY ON COERCIVITY OF ELECTROPLATING CoNdNiMnP PERMANENT MAGNETIC ALLOY FTLM ARRAYS

The influences of plating bath solution PH and current density on coercivity of electroplating CoNdNiMnP permanent magnetic film arrays were studied. The experiment results show that both for solution PH and current density there were the best depositing parameters. Too high and too low plating bath solution PH or current density both result in decreasing of the film array coercivity. When solution PH is 3.5 and current density is 5mA/cm^2, the prepared film array coercivity can reach the maximum.     

MAGNETIC ACOUSTIC EMISSION CHARACTERISTICS OF HYDROGEN ATTACKED LOW CARBON STEEL

ＭＡＧＮＥＴＩＣＡＣＯＵＳＴＩＣＥＭＩＳＳＩＯＮＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＨＹＤＲＯＧＥＮＡＴＴＡＣＫＥＤＬＯＷＣＡＲＢＯＮＳＴＥＥＬ￥ＬＩＨｉａｏｇａｎｇ;ＭＥＮＧＱｉｎｇｈａｉ;ＣＨＥＮＨｕａ;ＣＨＥＮＪｉｎｗｅｉ;ＹＡＯＺｈｉｍｉｎｇ;...     

THE INFLUENCES OF SOLUTION PH AND CURRENT DENSITY ON COERCIVITY OF ELECTROPLATING CoNdNiMnP PERMANENT MAGNETIC ALLOY FILM ARRAYS

1.IntroductionPermanent magnetic films, as an important type of functional films, have been widely used in vertical magnetic recording medium, magnetic field sensors, micro-actuators, optical insulators, optical switches,micropumps and scanners fields etc.[1-4]. Specially, with the development of micro electro-mechanical systems (MEMS), because of good resistance to bad environment and easily assembling, electromagnetic micro-actuators have been studied and fabricated by many researchers all …     

电流密度对AZ91D镁合金微弧氧化膜性能的影响

采用不同的氧化电流密度（20 mA/cm^2、50 mA/cm^2、70 mA/cm^2、100 mA/cm^2）,在碱性硅酸盐溶液中镁合金AZ91D表面制得了一系列的微弧氧化膜,并且利用体视显微镜方法、X射线衍射方法和电化学阻抗方法对膜层的表面形貌、结构组成以及电化学阻抗等性能进行了比较研究.结果表明,氧化电流密度越高,膜层的生长速度越快,膜层的晶化程度越高,但是膜层的粗糙度和孔隙率升高,阻抗反而下降.膜层的阻抗性能不是由膜层的总厚度决定,而是主要取决于氧化膜的致密程度.     

EFFECT OF ELECTRIC FIELD ON THE AUSTENIZATION OF A LOW CARBON STEEL

With an electric field during austenitizing, the martensite transformation of the low carbon steel was promoted, and more martensite were obtained. The electric field promotes the homogeneity of carbon, and reduces the free energy of austenite. The critical neuclus r^* and the critical driving force G^* responsible for the nucleation of proeutectoid ferrite were increased. As a result of which the diffusion controlled proeuctoid ferrite transformation was retarded and the hardenability was improved.     

STUDY ON THE PROPERTIES OF DIFFERENT ACTIVATED CARBON FIBERS AND THEIR ADSORPTION CHARACTERISTICS FOR FORMALDEHYDE

1. IntroductionOne of the undesirable features of the modern day world is the widespread coatami-nation associated with the release of a large number of chemicals into the environment.At presellt, people paid more and more attention to indoor air pollution than ever be-cause people almost spend their 8ty90% time in rooms everyday. FOrmaldehyde and otheraldehydes are main pollutans in indoor air. Formaldel1yde is a kind of poison. Highconceatrated formaldehyde can cause a 8eries of symptoms su…     

氮化硼纳米管的显微表征及其高分辨成像研究

采用化学气相沉积法制备了多壁氮化硼纳米管（BNNT）,高分辨电镜研究表明,BNNT一个重要的结构特征为层间有序堆垛,且大多以菱面体（r-BN）方式堆垛;多数BNNT具有择优生长取向,管轴沿BN六角网格平面的[1010]方向,即多数BNNT为锯齿型.基于其显微结构特征建立了多壁BNNT的结构模型,并通过计算机模拟其高分辨成像特点,发现r-BN堆垛的BNNT的HRTEM成像效果对其直径、层数以及观察视角等参数敏感,提出也可以通过管身高分辨像出现水纹状条纹直接判别r-BN堆垛.     

声发射信号处理和分析技术

介绍声发射技术发展简况，声发射信号处理面临的困难及目前所用的各种处理和分析方法。还介绍了声发射仪器的发展概况。     

耐候钢和碳钢大气腐蚀规律分析

对北京、青岛、江津、武汉地区的耐候钢与碳钢8年和16年的大气腐蚀数据进行方差分析,研究发现两类材料在北京地区的大气腐蚀数据无显著差异;在青岛、江津、武汉3个地区,虽然4年时耐候钢腐蚀速率明显低于碳钢,但8年和16年耐候钢与碳钢之间的腐蚀速率已无明显差异.     

碳钢和耐候钢的大气腐蚀

回顾了近年来碳钢和耐候钢大气腐蚀研究,比较了两种钢的腐蚀行为.重点分析了两种钢在腐蚀过程、腐蚀产物组成及影响因素等方面的相似性;同时讨论了两种钢的腐蚀速度和锈层结构的差异性.     

PREPARATION OF MULTI-WALLED CARBON NANOTUBES USING NiO CATALYST SYNTHESIZED BY HYDROTHERMAL METHOD

The Ni(OH)2/SiO2 binary colloid was prepared using Ni(NO3)2.6H2O and (C2H5O)4SiO4 as starting materials and was used to form NiO/SiO2. composite powder by hydrothermal method and desiccant method in open air respectively. Multi-walled carbon nanotubes (MWCNTs) were synthesized respectively by chemical vapor deposition using the NiO/SiO2 catalyst prepared by different methods. The phase and morphology of the catalysts and the morphology, output yield and purity of MWCNTs were compared by XRD, TEM and SEM. The results show that the catalyst powder prepared by hydrothermal method, compared with that by desiccant method, is smaller, better dispersion and has stronger catalytic activity. Pure MWCNTs with smaller tube diameter and narrow range could be obtained at a high yield using that NiO/SiO2 powder prepared by hydrothermal method as catalyst.     

ELECTROANALYTICAL APPLICATIONS OF CARBOXYL-MODIFIED CARBON NANOTUBE FILM ELECTRODES

The electrochemical behavior of a carboxyl-modified carbon nanotube films was investigated to explore its possibility in electroanalytical applicaton. Cyclic voltammetry of quinone was conducted in 1mol/L Na2SO4, which showed a stable, quasi-reversible voltammetric response for quinone / hydroquinone, and the anodic and the cathodic peak potentials were 0.657V and -0.029V (vs. SCE) at a scan rate of 0.1V.s-1, respectively. Both anodic and cathodic peak currents depended linearly on the square root of the scan rate over the range of 0.01-0.5V.s-1, which suggested that the process of the electrode reactions was diffusion-controlled. Carboxyl-modified carbon nanotube electrodes made it possible to determine low level of dopamine selectively in the presence of a large excess of ascorbic acid in acidic media using derivative voltammetry. The results obtained were discussed in details. This work demonstrates the potential of carboxyl-modified carbon nanotube electrodes for electroanalytical applications.     

碳纤维表面气相生长碳晶须

用铁做催化剂,乙炔做原料气体,在碳纤维表面上长出二级增强相——碳晶须初步考察了生长温度、铁盐溶液浓度对碳晶须生长的影响结果表明,碳晶须生长的最佳温度在1000℃左右,在催化剂溶液浓度适当时,碳晶须均匀分布在母体纤维上,并把相邻的碳纤维连结起来;温度过高或催化剂溶液浓度过高,都会在碳纤维表面上形成大块碳沉积团碳晶须的生长是气相中的碳原子溶解于纤维表面上的催化剂液滴后,在液滴底部的碳纤维表面上析出固体碳的动态过程