Effects of cerium on the microstructure and mechanical properties of AZ31 alloy

AZ31 alloy with Ce addition was studied. The influence of Ce contents on the microstructure and tensile properties of the alloy was analyzed. Ce addition results in the formation of AlzCe and the annealed microstructure is improved by the addition. There was no recrystallization of the alloy after rolling, however, it did occur after annealing. The alloy can be strengthened by adding Ce and the alloy with 1.05 wt.% Ce possessed the best synthetical properties of all the tested alloys. As rolled, σb and δof this alloy are 321 MPa and 6.9%, and as annealed, they are 259 MPa and 21.8%.     

Effect of microstructural parameters on the properties of W-Ni-Fe alloys

The aim of this research was to examine the effect of microstructural parameters on the tensile properties of dif- ferent compositions of tungsten heavy alloys. The microstructural parameters (grain size, connectivity, contiguity, and solid volume fraction) were measured and were found to have a significant effect on the tensile properties of tungsten-based heavy alloys. The microstructural parameters of W-Ni-Fe alloys are sufficiently different to present a range of me- chanical properties. It is concluded that the mechanical properties of tungsten heavy alloys largely depend on the micro- structural parameters and their ductility is particularly harmed when grains are contiguous.     

Synthesis of Y-junction carbon nanofibres by ethanol catalytic combustion technique

Y-shaped structure was synthesized by ethanol catalytic combustion（ECC） technique on the copper plate substrate, without directly seeding catalyst into the flame. The as-grown Y-junction carbon nanofibres were investigated by transmission electron microscopy （TEM）. The very common laboratory ethanol burner was used for synthesizing carbon nanofibres. Two kinds of the catalyst precursor, which are iron nitrate （Fe（NO3）3） and nickel nitrate （Ni（NO3）2）, were respectively employed to assist the formation of Y-junction carbon nanofibres. TEM analysis confirm the formation of Y-junction in the coiled and noncoiled carbon nanofibres. The type of the catalyst is found to be crucial to grow different Y-junction carbon nanofibres. Different Y-shaped structure may possess different mechanical and electronic properties. These three-terminal nanofibres provide the nanoelectronics community with a novel material for the development of molecular-scale electronic devices.     

Influences of the Welding Heat Input and the Repeated Repair Welding on Ti–3Al–2.5V Titanium Alloy

The primary purpose of this study was to determine the effects of gas tungsten arc welding heat input on the high-temperature tensile properties, toughness, and microstructural features of titanium alloy Ti–3Al–2.5V. The secondary objective was to examine the effect of the repeated repair welding on the properties of the alloy. It was also found that the mechanical properties progressively decreased with increasing the repair welding cycles, especially in the case of the weldment after the first welding repair. It was observed that the sizes of the acicular α' and prior β grain boundaries as well as the volume fraction of the acicular α' phases increased with increasing the welding heat input. In addition, the amount and size of the acicular α' phases were found to increase with increasing the repair welding cycles.     

Effect of heat input on microstructure and properties of welded joint in magnesium alloy AZ31B

Using the optical microscope, tensile test machine and micro-hardness meter, the effect of heat input on the microstructure and mechanical properties in fusion welding joints of AZ31B wrought alloys was investigated systematically, the mechanism on joint properties losing was analyzed, and a valid method to improve joint properties of the magnesium alloy fusion welding was explored. The results show that the heat input has an obvious effect on the microstructure and properties. Under the condition of penetration, with the heat input decreasing, the crystal grain in the weld and heat-affected zone (HAZ) becomes fine, the width of HAZ becomes obviously narrow, and the molding of the weld is improved, so the tensile strength and elongation are increased and the hardness of joints is improved. When the heat input reaches 60 J/mm, the high quality joints can he gained.     

Preparation of carbon nanotubes by ethanol catalytic combustion technique using nickel salt as catalyst precursor

A simple growth technique of carbon nanotubes （CNTs） by combustion of ethanol was developed. In the experiment, copper plate was employed as substrate, nickel nitrate （Ni（NO3）2） and nickel chloride （NiCl2） as catalyst precursor, and ethanol as carbon source. The cleaned copper substrate was dipped into catalyst precursor solution for mounting catalyst precursor particles. The dip-coated substrate was then placed into ethanol flame for about 10 min after drying. The black wool-like production grown on copper plate was obtained. This route is called an ethanol catalytic combustion（ECC） process. The black powders were characterized by means of scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, energy dispersive X-ray spectrometer（EDS） and Raman spectroscopy. The results show that the techique is much simpler and more economical to meet the future broader applications.     

Orientation Dependence of the Micro-Pillar Compression Strength in an Electron Beam Melted Ti–6Al–4V Alloy

An α/β two-phase Ti-6 Al-4 V alloy was fabricated by electron beam melting to obtain a basketweave structure.The orientation dependence of the mechanical properties of Ti-6 Al-4 V alloy was studied by micro-pillar compression and post-mortem transmission electron microscopy analysis.The results indicate that different grains have different mechanical responses,and the possible attributions were discussed.Besides the orientation effect,due to the limited volumes of micropillars,the size of the a phases,dispersion of the β phases,and the presence of the free dislocation path also affect the mechanical properties of the micropillars to a large extent.Although no direct link was discovered between the mechanical properties and the parent βorientations,this work provided a promising method to further study the anisotropic mechanical behavior in Ti-6 Al-4 V alloy.     

Effect of Annealing on the Magnetism of the Sintered NdFeB Magnet

This paper deals with the effect of annealing on the magnetism of the sintered NdFeB magnet with a composition of Nd30B5.1Dy1.2Al0.6Nb0.7Fe62.4. Microstructural investigations of the grain size and grain boundaries with SEM were carried out. Microstructural investigations showed the presence of some Nd-rich phase in grain boundaries and main phase.The results of magnetic properties analysis shows that this non-magnetic Nd-rich phase, produced in annealing process,can increase or decrease the magnetism of the sintered NdFeB-type permanent magnet. Appropriate amount of Nd-rich phase will strengthen the pinning field and elevated the coercive force of magnet, but too many these non-magnetism phases in Nd2Fe14B main phase will decrease it. When the sintered NdFeB magnet was annealed at 3Pa and 492℃ for an hour the coercive force would raise from 915.6kA/m to l164.SkA/m, and the (BH)max from 277.7kJ/m to 349.5kJ/m. However, annealing at a non-optimized temperature at 542℃, microstructure changes in some main phase will leading the decrease of properties.     

Model Investigation on Composite Failure Prediction of π-Joint Structures

This paper was concerned with the tensile mechanics behavior of the composite π-joint under static tensile loading. The numerical strength analysis methodology was presented containing the basis assumption for the analysis, the material modeling, and the selected element type. It was assumed that the composite ply had transverse isotropic material properties and the adhesive had linear elastic properties. With the goal of the strength analysis to determine the onset of the damage initiation and the ultimate...     

Influence of alloying elements on mechanical properties of Al-Li plates

The effect of alloying elements such as Cu, Mn and Zr on the mechanical properties of the Al-Li plates was studied, and the grain structure, crystallographic texture and precipitates were also investigated. It is found that the element Zr has a two-fold effect on the anisotropy of mechanical properties; the addition of element Mn can reduce the crystalline texture and the anisotropy of Al-Li plates. However, the effect of Cu element appears less pronounced.     

Enhancement effect of organic solvents on the line intensity of lower power argon ICP-AES:Part Ⅰ On the nebulization procedure

The anaIytical merits and strong emission ca-pacity of ICP-based techniques demonstrated itspOtCfltial power in the analysis of organic anaIy-te and high concentration samples. The advan-tages of the introduction of organic samples,such as the simplification of the pretreatment,enlarged the applied area of ICP-AES. Forexample, it can be used as the detector of HPLCor GC for the analysis of organic solutions. Infact, the application of ICP-based techniques onthe direct ana1ysis of orga…     

联合吸入硫酸镁及沙丁胺醇治疗哮喘的临床研究

目的 探讨联合吸入7.5 %等渗硫酸镁及1 %沙丁胺醇对发作期哮喘患者肺功能的影响。 方法 将75 例发作期哮喘患者随机分成A、B、C3 组, 每组25 人。A 组雾化吸入7.5 %等渗硫酸镁溶液3 ml后间歇5 min, 再吸入生理盐水3 ml。B 组雾化吸入0.1 %沙丁胺醇3 ml 后, 间歇5 min 再吸入生理盐水3 ml。C 组雾化吸入0.1 %沙丁胺醇3 ml 后, 间歇5 min 再雾化吸入7.5 %等渗硫酸镁溶液3 ml。于吸药前、后15 min 分别作用力肺活量(FVC)、1 秒钟用力呼气容积(FEV1)、最大呼气流量(PEF) 的检查,并分别测A、C 两组吸药前后收缩压、舒张压、心率、呼吸的变化。 结果 3 组吸药前后肺功能指标占其正常预计值的百分比浓度(FVC %、FEV1 %、PEF %) 比较均有显著性差异(P <0.05);3 组间吸药后15 min肺功能比较:B 组显著高于A 组(P <0.05);C 组非常显著高于B 组(P <0.01) 和A 组(P <0.01)。A组及C 组吸药前后收缩压、舒张率、心率和呼吸频率差异均无显著性(P >0.05)。 结论 联合吸入7.5 %等渗硫酸镁及1 %沙丁胺醇对发作期哮喘患者的治疗有协同作用, 能明显改善通气功能, 且对患者的血压、心率、呼吸无明显影响。     

乙醇对低磨料CMP过程中铜膜凹凸处去除速率选择性的影响

根据相似相容原理,在低磨料浓度CMP过程中,利用乙醇对多羟多胺螯合剂的降黏特性来提高铜膜表面凹凸处抛光速率的选择性。根据抛光液中各组分浓度对动态和静态条件下铜膜去除速率的影响获得乙醇加入量的最大值;通过螯合剂、氧化剂与乙醇对动静态条件下铜膜去除速率的相互作用关系来确定各组分的最佳浓度。最终得出当各组的体积分数为:磨料0.5%,螯合剂10%,H2O20.5%,乙醇1%时,铜膜表面拥有最大的凸处和凹处速率比。在MIT 854铜布线片上进行平坦化试验,结果表明:该抛光液能够很大程度的减小布线表面的高低差,拥有较强的平坦化能力。红外光谱检测结果表明:在CMP过程中,铜膜表面不会生成副产物乙酸乙酯。上述结果进一步证实了该抛光液的实用性。     

香椿子提取物对实验性小鼠胃黏膜损伤保护作用

目的：研究香椿子提取物对小鼠胃黏膜损伤的保护作用。方法：按200、400 mg·kg-1·d-1香椿子生药量给小鼠连续灌胃给药2周,采用乙醇及阿司匹林诱发胃黏膜损伤模型,通过计算胃黏膜损伤指数和损伤抑制率,测定小鼠血清中超氧化物歧化酶（SOD）、丙二醛（MDA）的水平和胃黏膜组织中内皮素-1（ET-1）、前列腺E2（PGE2）、一氧化氮（NO）含量来探讨香椿子提取物对损伤的保护情况。 结果：预防给药14 d后,香椿子能明显降低乙醇及阿司匹林诱发的胃黏膜损伤指数,两个剂量组对乙醇诱发的胃黏膜损伤抑制率分别为40.4%和47.4%,对阿司匹林诱发的胃黏膜损伤抑制率分别为38.9%和44.6%。阳性对照药西米替丁对乙醇及阿司匹林诱发的小鼠胃黏膜损伤抑制率分别为50.9%和50.2%。此外,与乙醇及阿司匹林诱导的模型动物组比较,香椿子200、400 mg/kg剂量组能升高小鼠胃黏膜组织中SOD、PGE2与NO水平,降低MDA和ET-1含量。 结论：香椿子提取物对乙醇及阿司匹林所致小鼠胃黏膜损伤均具有一定的保护作用。     

Ultrasonic welding of heat-treatable aluminium alloy A6061 sheet

In this study, the authors applied the ultrasonic welding method to weld A6061 heat treatable aluminium alloy and investigated the effects of clamping load and welding time on the properties of the weld. In addition, in order to improve the strength of the joint, the effectiveness of the ethanol droplet on the faying surface was examined. The following results were obtained.

The joint strength increased with clamping load and welding time. The fracture of the joint produced under the welding conditions of 1176 N clamping load and 1.5 s welding time occurred in the base metal. The ethanol droplet on the faying surface successfully produced the joint with a strength equivalent to that of the base metal under the welding conditions of smaller clamping load and shorter welding time than the case without ethanol droplet. The softening around the welded area that was performed with the ethanol droplet was smaller than that in the welded area produced by other methods such as TIG and friction stir welding. The fracture surface of the joint welded with the ethanol droplet was remarkably irregular and rough. A dimple pattern was observed over a wide area, indicating that the welded area was significantly expanded. The ethanol droplet made the temperature of the weld area higher than that without ethanol, resulting in improved joint strength with an increase of the plastic deformation at the interface.     

爱全乐等氧气雾化吸入对减轻术后咳嗽、咳痰及降低肺部感染的临床研究

目的: 探究爱全乐等氧气雾化吸入对减轻术后咳嗽、咳痰及降低肺部感染的疗效。方法: 将本院104例接受手术后出现咳嗽、咳痰现象的患者随机均分为研究组和对照组,每组各52例。研究组进行爱全乐氧气雾化治疗,对照组进行常规超声雾化。结果: 研究组的患者术后咳嗽、咳痰及降低肺部感染恢复情况较对照组更加好和快,差异具有统计学意义(P<0.05)。与此同时,研究组并发症情况少于对照组,差异同样具有统计学意义(P<0.05)。结论: 爱全乐等氧气雾化吸入,有助于患者术后进行咳痰以及排痰,同时减轻咳嗽情况以及降低患者肺部感染,值得在临床上推广应用。     

Effects of filler and ethanol on mechanical properties of glass-like carbon

The effects of filler and ethanol on the mechanical properties of glass-like carbon were studied. The specific gravities of glass-like carbons with the filler were higher than those of alcohol added glass-like carbons due to the formation of pores and bubbles as the alcohol was vaporized in the curing and polymerization stages. The ethanol added glass-like carbon samples also had lower bending strength than the filler added glass-like carbon samples after carbonization; a contrary result was observed after heat treatment at 2600°C. This was due to the pores that were made with ethanol which plays the role of pore former during carbonization. The fabricated glass-like carbons are quite brittle material. The shore hardness of the glass-like carbon was observed not to be affected by the addition of filler or ethanol, but increased a lot after carbonization.     

Ti3SiC2在水、乙醇及其混合溶液中的摩擦学行为研究

目的考察新型可加工金属陶瓷材料Ti_3SiC_2在水基润滑系统(如水液压系统)及乙醇润滑系统(如乙醇燃料系统)中的摩擦学行为。方法利用中频热压烧结技术制备Ti_3SiC_2样品,用球盘接触模式SRV-1摩擦磨损试验机考察Ti_3SiC_2/Si_3N_4摩擦副的摩擦学行为,利用扫描电子显微镜、X-射线光电子能谱、X-射线衍射谱等分析材料的形貌和成分物相。结果 Ti_3SiC_2/Si_3N_4摩擦副在乙醇中具有较低的摩擦系数(0.14)和磨损率(10~(-7) mm~3/(N×m)),但在纯水中,其摩擦系数(0.54)和磨损率(10~(-4) mm~3/(N×m))均较高。乙醇中少量的水(5%)即可使Ti_3SiC_2/Si_3N_4的摩擦学性能恶化,乙醇中Ti_3SiC_2磨损表面为轻微犁沟效应,随着乙醇中水含量的增大,Ti_3SiC_2晶粒拔出和脱落造成的坑洞增加,因此磨损率迅速增大。纯水中呈现大量的坑洞,相应的磨损率也达到最大值。结论乙醇是Ti_3SiC_2/Si_3N_4摩擦副很好的低黏度流体润滑剂,在乙醇中,摩擦表面的高化学活性Si元素与乙醇发生了摩擦化学反应,生成的硅醇聚合物在摩擦接触界面形成了边界润滑,致使Ti_3SiC_2/Si_3N_4摩擦副在乙醇中具有优良的润滑和减磨作用。     

乙醇在修饰铂电极上的电化学氧化

为了改善铂基催化剂氧化乙醇的活性,制备磷钼酸修饰铂电极,并利用循环伏安曲线评价其对乙醇氧化的电催化活性及抗CO毒化作用。结果表明：磷钼酸修饰铂电极可以提高铂基电极氧化乙醇的催化活性以及抗CO毒化作用     

Effects of Adding Sodium and Ethanol Inhibitor on Inhibiting H2 Evolution of Lithium Anode

在30℃的4mol/LLiOH电解质溶液中,通过测量锂负极的自腐蚀析氢速率、极化曲线、电化学阻抗谱及电位-时间曲线,研究了Na作为合金元素及乙醇作为添加剂对锂负极的共同抑制自腐蚀析氢作用。结果表明:合金元素Na及乙醇对阴阳极反应都起到了抑制作用,但是单一添加合金元素Na或者乙醇缓蚀剂对锂负极的抑氢作用不大,而当共同添加合金元素Na及乙醇时对锂负极的抑氢效率提高明显,缓蚀率超过了80%。另外,单独添加合金元素Na时,锂负极的放电性能极不稳定,而溶液中添加乙醇后有利于提高锂负极的放电稳定性。XRD结果表明,钠与锂形成了比较理想的固溶体。