化学镀和粉末冶金法制备W/Cu梯度热沉材料

用化学镀法和粉末冶金的方法制备高致密的W/Cu梯度热沉材料。用场发射扫描电镜观察了材料的组织结构、界面和断口形貌。对材料的机械性能也进行了表征,如抗弯强度和显微硬度。结果表明材料每一层都很致密且组织结构均匀。从截面上材料成分呈梯度分布,每层之间没有明显的界面。三层W/Cu梯度热沉材料的相对密度可达99.2%。散热层、过渡层和封接层的显微硬度值分别是200、210和240 HV。抗弯实验结果所示封接层和散热层作为承重抗弯表面时的抗弯强度分别是428.5MPa和480.7MPa。     

Mulliet／Al—4.5Cu复合材料的时效析出行为

选用挤压铸造法制备mullite/Al-4.5Cu复合材料,采用硬度测试（HB）、差示扫描量热DSC、透射电镜（TEM）等手段研究了mullite/Al-4.5Cu复合材料的时效特性。结果表明：莫来石纤维的引入明显提高了基体合金的时效硬度,加速了基体合金的时效硬化速度,对GP区的形成有抑作用,但没有改变基体合金的时效析出序列。复合材料具有和基体合金相似的时效硬化曲线。温度对两类材料时效硬化行为的影响基本一致。     

Microstructure and electrical conductivity of A-site fully stoichiometric Na0.5+xBi0.5−xTiO3−δ with different Na/Bi ratios

The effect of nominal Na/Bi ratio on the microstructure and electrical conductivity of A-site fully stoichiometric sodium bismuth titanates, Na_0.5+xBi_0.5?xTiO_3?δ, was investigated in this study. Bulk samples with x?=?0, 0.01, 0.03, 0.05, 0.07, and 0.1 were prepared by conventional solid state reaction method. The as-calcined powders primarily exhibited the perovskite structure, which was identified by X-ray diffraction. Electron microscopic investigation of the sintered samples, however, revealed the presence of secondary phases, the amounts of which were found to increase with increasing Na/Bi ratio. Further elemental analysis by energy dispersive spectroscopy indicated that the secondary phases were mainly composed of sodium titanates with different Na/Ti ratios. The grain bulk and grain boundary conductivities of Na_0.5+xBi_0.5?xTiO_3?δ, measured by two-probe AC electrochemical impedance spectroscopy, significantly increased with increasing Na/Bi ratio when x?≤?0.03, but remained almost constant at higher x. The synergetic effect of oxygen vacancy creation, grain size reduction, and secondary phase formation on the variation in the conductivity upon increasing the nominal Na/Bi ratio in Na_0.5+xBi_0.5?xTiO_3?δ was discussed.     

气相爆轰法制备球形铜纳米粒子及其形成机理

本文以氢氧混合气体为爆炸源,乙酰丙酮铜(II)为前驱体,采用操作简单、高效的气相爆轰方式合成了类球形的铜纳米晶颗粒。进一步采用XRD、TEM、SAED和EDX对所获得产物的形貌特征、物相组成和微观结构进行了表征和分析。同时为了预测气相爆轰流场中铜纳米颗粒的生长特性,将Kruis模型引入气体爆轰反应程序中。研究结果表明：实验合成的类球型FCC结构纳米铜晶体分散性良好,平均粒径在24 nm左右且纳米铜晶体外包覆了1nm左右的较薄石墨层。基于Kruis模型对球形铜纳米粒子的生长特性预测结果与实验数据吻合较好,为可控合成铜纳米粒子提供了可靠的理论指导。     

灵捷虚拟企业盟主问题的研究

分析了盟主的角色，引入了盟主就是虚拟企业家的概念，提出了盟主所承担的五大职能。在此基础上，探讨了个人／或企业作为盟主的必备条件，认为在知识拥有方面具有比较优势的个人或企业更适合作盟主。揭示了虚拟企业知识驾驭资本的委托权结构，并阐明了知识驾驭资本的含义。     

Optical dispersion and dielectric properties of rubrene organic semiconductor thin film

Rubrene thin film has been fabricated on a glass substrate by spin-coating at 300 K. The optical dispersion and dielectric properties of the film have been determined from the analysis of transmittance and reflectance measurements at normal incident of light between 200 and 700 nm. The optical transmittance of the film was estimated as of 80–85 % in the visible range. Optical absorption characteristics show that the absorption mechanism is due to the indirect transition. The transport and onset optical energy gaps were determined as 2.93 and 2.31 eV, respectively. Single term Sellmeier dispersion relation and Wemple–DiDomenico single oscillator model were used to determine the optical dispersion parameters. Several dispersion parameters such as lattice dielectric constant, optical dielectric constant at higher frequency, dispersion energy, oscillator energy, the ratio of carrier concentration to the effective mass, the average oscillator wavelength, and average oscillator strength were determined by analysis of refractive index dispersion. The loss factor, the electric modulus, the optical conductivity, the volume and surface energy loss functions, and the relaxation time were also evaluated from the optical dielectric constants analysis.     

氰化浸出废水处理方法研究进展

本文介绍了氰化浸出废水的主要处理方法,将其归结为两类处理方法：1)直接分解破坏法;2)回收利用氰化物法。并结合氰化废水的特点对各种处理方法的优缺点分别进行了分析。各黄金生产企业可根据废水的实际性质和具体处理要求,选择合适的处理方法,可选择单一处理方法,也可选择几种上述方法进行联合处理。     

鹰嘴豆膳食纤维对高脂血症大鼠脂代谢的改善作用

本研究观察了鹰嘴豆膳食纤维对高脂血症大鼠血脂及抗氧化水平的影响,为鹰嘴豆保健功效研究提供参考依据。40只雄性SD大鼠高脂饲料喂养建立高脂血症模型,将造模成功的大鼠,随机分为高脂模型组,鹰嘴豆膳食纤维高(30 g/kg高脂饲料)、中(15 g/kg高脂饲料)、低(5 g/kg高脂饲料)3个干预组。高脂模型组继续喂以高脂饲料,干预组分别喂以含不同含量鹰嘴豆膳食纤维的高脂饲料。干预7周后,处理动物,分别测定各组大鼠体重、肝重、附睾周脂重,血清血脂水平及氧化应激水平。结果表明:与高脂模型组相比,鹰嘴豆膳食纤维组体重增量、肝重、附睾周脂重均有下降,其中体重增量以干预第5周高剂量组下降最为明显,降低:29.34%,高中低各剂量组附睾周脂重分别降低:33.81%,17.28%,21.86%,但肝重降低无统计学差异;血脂方面,甘油三酯(TG)、低密度脂蛋白(LDL-C)值高剂量组降低:51.52%,40.45%,总胆固醇(TC)值以中剂量组最优,降低:34.31%,高密度脂蛋白(HDL-C)高剂量组升高42%;在抗氧化能力方面,中剂量组丙二醛(MDA)含量降低40%,高剂量组总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)水平分别升高54%,55%,且T-SOD、GSH-Px升高呈现剂量相关性。可见鹰嘴豆膳食纤维具有降低高脂血症大鼠体质量,调节异常血脂作用,而这种作用可能与其提高高脂血症大鼠抗氧化能力,降低氧化应激损伤有关。     

潮湿养护提高掺矿物混凝土强度和耐久性能

粉煤灰、矿渣等矿物掺合料具有火山灰性或潜在水硬活性,只有在Ca(OH)2(或CaO)和潮湿的环境下才能缓慢反应生成具有胶凝性的C-S-H凝胶和水化铝酸钙.文章详细介绍了粉煤灰和矿渣的水化特性,列举了大量养护制度对掺混合材水泥和掺矿物掺合料混凝土强度和耐久性的影响的研究成果和实例,说明了对掺矿物掺合料特别是掺粉煤灰的混凝土必须注意湿养护,尤其是在干燥灼热的季节或地区,大掺量粉煤灰混凝土更应该较长的或长期的潮湿养护.     

W-Ni/Yb2O3复合材料的制备及烧结性能研究

本文首先采用化学镀获得Ni-Yb2O3复合粉体,然后通过机械球磨制备了不同成分的W-（0.2、0.5、1、2）wt% Ni/Yb2O3复合粉末,最后在1600℃下烧结3h获得了W-Ni/Yb2O3复合材料。采用场发射扫描电子显微镜(FE-SEM)研究分析了Ni-Yb2O3复合粉体形貌、W-Ni/Yb2O3复合材料表面形貌。测定了W-Ni/Yb2O3复合材料相对密度、显微硬度和热导率。实验结果表明,W-Ni/Yb2O3复合材料的相对密度和显微硬度随着Ni-Yb2O3含量增加而增加,Ni-Yb2O3的加入促进了钨基材料的烧结致密化;同时,添加Ni-Yb2O3复合粉使钨基材料的晶粒得到细化,但对钨基材料导热性起到降低的作用。