基片方向对多弧离子镀ZrN涂层性能的影响

采用多弧离子镀在304不锈钢基体表面沉积ZrN涂层。利用X射线衍射仪、扫描电子显微镜、纳米压入仪、电化学分析仪等，比较了基片方向对涂层结构、形貌、成分、沉积速率、硬度以及耐腐蚀性的影响。结果表明：基片方向不同会引起晶体择优取向的改变；垂直于靶材的样品表面大颗粒相对较少，但沉积速率只有平行样品的40％-50％；在负偏压条件下，平行于靶材的样品涂层硬度更高，而垂直样品获得更好的耐腐蚀性。     

工作电压对喷射电沉积Ni镀层形貌及性能的影响

采用喷射电沉积技术制备了Ni镀层。研究了工作电压对电流特性、镀层表面形貌、显微硬度和摩擦学性能的影响。结果表明：随着工作电压的升高,平均电流密度逐渐增大,镀层的显微硬度和耐磨性逐渐增强,镀层表面的平整度和减摩效果下降。     

纳米硼酸镧的制备、表征及其在水介质中的摩擦学性能

采用化学沉淀法合成了硼酸镧纳米微粒,利用透射电镜、热分析仪、FT-IR光谱仪对其结构进行了表征,采用四球摩擦试验机考察了其在水介质中的摩擦学行为,并用扫描电子显微镜和X射线光电子能谱分析了磨损表面形貌和主要元素的化学状态.结果表明,纳米硼酸镧作为水基润滑添加剂能显著提高水的抗磨减摩性能,添加剂在摩擦过程中发生了摩擦化学反应,在摩擦副表面生成了含La2O3,B2O3,FeO和Fe2O3的复合润滑膜,有效地提高了水的抗磨减摩性能.     

化学气相沉积碳化硅超光滑抛光机理与表面粗糙度影响因素

为实现化学气相沉积碳化硅(CVD SiC)的超光滑抛光,采用纳米划痕试验研究了化学气相沉积碳化硅脆塑转变的临界载荷,根据单颗磨粒受力对其抛光机理进行了分析,并从材料特性、工艺参数以及抛光液pH值三个方面对其表面粗糙度影响因素进行了系统的试验研究.研究结果表明:化学气相沉积碳化硅的稳定抛光过程是磨粒对碳化硅表面的塑性域划痕过程;CVD SiC的晶粒不均匀与表面高点会降低晟终所能达到的表面质量;表面粗糙度在一定范围内随磨粒粒度增加呈近似线性增长,随抛光模硬度的增加而增长;抛光压强对表面粗糙度的影响规律与抛光模的变形行为相关,当抛光模处于弹性或弹塑性变形阶段时,表面粗糙度随抛光压强的增加呈小幅增长,而当抛光模包含塑性变形之后,表面粗糙度基本与抛光压强无关;此外,抛光速度和抛光液pH值对表面粗糙度的影响不大.研究结论为CVD SiC超光滑抛光的工艺参数优化选择提供了定量的试验依据.     

一维金属-介质光子晶体的特性

利用特征矩阵法对一维金属-介质光子晶体的特性进行了计算,发现此种光子晶体具有可见光透明,微波、紫外高反的光谱特性,而且存在比一维介质光子晶体更宽、反射更强的全向带隙.     

InSb纳米颗粒的制备与原子力显微镜

为进一步研究半导体纳米材料的物理特性,用真空沉积的方法在SiO2基片上制备了纳米InSb颗粒膜。用原子力显微镜扫描样品表面的分析显示,纳米InSb颗粒均匀地分布在SiO2基片表面。实验结果表明通过改变镀膜时间,可以得到具有不同颗粒尺寸的InSb纳米颗粒。     

Ni-P-SiC 化学复合镀

采用化学共沉淀法对Ni P SiC化学复合镀研究 ,通过能谱仪和扫描电镜分析了镀层的组成与形貌 ,并对镀层的硬度、耐腐蚀性能进行了研究。结果表明 ,镀层硬度随SiC微粒浓度加大而增加 ;镀液中SiC微粒的浓度和镀液的pH值对镀层中SiC微粒的含量有影响 ;在SiC浓度为 7 5g/L时镀层中SiC含量达到最大值 1 6 81 % ;而pH值的最佳值为 4 7;同时 ,由于SiC微粒的加入 ,镀层表面色泽变暗 ,外观较粗糙 ,镀层的耐腐蚀性降低。     

膜型声子晶体原胞结构隔声性能试验研究

针对船舶舱室噪声低频控制问题，以一种薄膜型声子晶体原胞结构为研究对象，采用阻抗管法进行隔声性能试验研究，探究了不同配重质量、薄膜厚度和框架厚度对其隔声性能的影响规律。试验研究结果表明：配重质量、薄膜厚度和框架厚度增加均能提升薄膜型声子晶体的隔声性能，其中以配重质量影响最为明显；相较于无配重及单侧配重情况，双侧配重的薄膜型声子晶体隔声频段大幅拓宽，隔声量在中低频及高频显著增加，低频略有降低；增加薄膜厚度及框架厚度均可有效向低频拓宽薄膜型声子晶体的隔声频段并提高隔声量，以增加框架厚度，对低频隔声性能的提升更为明显。     

轰击能量对Ti-Si-N纳米复合膜生长与力学性能的影响

采用离子束辅助沉积法(IBAD)在单晶硅片上制备了Ti-Si-N纳米复合薄膜,研究了轰击能量大小对Ti-Si-N纳米复合薄膜生长及力学性能的影响,同时探讨了轰击能量对Ti-Si-N纳米复合薄膜的生长机理的影响.通过原子力显微镜(AFM)、纳米压入仪、光电子能谱(XPS)和X射线衍射分析(XRD)等现代分析技术,对Ti-Si-N纳米复合薄膜的晶粒大小、力学性能、成分与相结构进行综合表征分析.试验结果表明当轰击能量为700 eV时,Ti-Si-N薄膜晶粒直径达到了最小值11 nm,此时Ti-Si-N薄膜的硬度相对最高,为33 GPa.     

镍对重力分离SHS陶瓷内衬复合管的影响

采用SHS重力分离技术制备陶瓷内衬复合管,通过改变主燃烧配系组元Ni的含量,研究分析了金属Ni对陶瓷内衬复合管制备的燃烧特性及机械性能的影响。研究发现,适量的Ni粉能促进SHS燃烧进行,提高燃烧体系的绝热燃烧温度和陶瓷层的致密度,并且有助于形成金属/陶瓷界面过渡层,这极大提高了复合管的显微硬度和抗压剪强度。当Ni粉含量为19wt％时,陶瓷层的显微硬度和抗压剪强度分别最高达1764N/mm2和36.1MPa。     

Artisanal small-scale opal mining (ASOM) insecurity in the Delanta wereda,Ethiopia: The shifting landscape of multidimensional insecurity in the face of emergent ASOM wealth

The commencement of opal mining in Ethiopia a decade ago has attracted the involvement of poor peasants, wealthy traders and traffickers. Although the academic and official literature on artisanal small-scale opal mining (ASOM) has primarily focused on the loss of wealth owing to a lack of skill and its traditional nature, this study explores the multidimensional insecurity that the discovery and mining of opal stones in the Delanta wereda of Wollo has brought about. This study contends that the ASOM industry has brought a new and previously unknown body of wealth to a society that is not used to the circulation of huge amounts of money in its narrow geography of commerce, engendering multidimensional insecurity. To make things worse, the network of patrimony and rentierism connecting locals with powerful people at the regional and federal level has given licence to illegal wealth extraction at the cost of exacerbating local insecurity. The qualitative data for the study was collected using interviews, focus group discussions, non-participant observations and document analyses at Delanta mining sites, the Wegel Tena town administration and Dessie city.     

界面改性对SiCp/Cu复合材料导热性能的影响*(复合材料专题)

采用磁控溅射法结合结晶化热处理工艺在碳化硅（Silicon Carbide, SiC）颗粒表面成功制备了金属钼（Molybdenum, Mo）涂层，分析了Mo涂层的成分和形貌；然后采用热压烧结工艺制备了SiCp/Cu复合材料，重点对比分析了Mo界面阻挡层厚度对复合材料导热性能的影响。结果表明：磁控溅射法能够在SiC颗粒表面沉积得到Mo 涂层，随溅射时间的延长Mo涂层的厚度增加、粗糙度增大，且磁控溅射后SiC颗粒表面直接得到的Mo涂层为非晶态，结晶化热处理后，变为致密平整的晶态Mo涂层。磁控溅射时间即Mo涂层厚度对复合材料导热性能影响明显，随磁控溅射时间的增加，复合材料的热导率呈现先增后减趋势，采用磁控溅射9h镀Mo改性并经过800℃结晶化热处理的SiC复合粉体在850℃下热压烧结制备的SiCp/Cu复合材料（VSiC=50%），其热导率达到了最高值274.056W/(m·K)。     

Improving the damage potential of W-Zr reactive structure material under extreme loading condition

Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gun-powder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propa-gation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops the W-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.     

用于SiC光学材料高效加工的电弧增强等离子体加工方法*

由于SiC光学材料具有高化学稳定性,使其在普通的等离子体加工中难以获得较高的加工效率。在等离子体加工实验中,我们发现提高等离子体的自身射频电压,可增强等离子体与SiC材料之间的电弧放电作用,而借助电弧的增强作用提高SiC材料的加工效率,因此本文提出了电弧增强等离子体加工方法。为研究电弧的形成原理,本文使用自制的探针分别测量了普通电感耦合等离子体和电弧增强等离子体的电压。并分别使用传统方法和电弧增强方法对S-SiC进行直线扫描加工实验,证明了电弧增强等离子加工方法在加工过程中具有更高的加工效率。     

Nanothermite colloids: A new prospective for enhanced performance

Nanothermites (metal oxide/metal) can offer tremendously exothermic self sustained reactions. CuO is one of the most effective oxidizers for naonothermite applications. This study reports on two prospectives for the manufacture of CuO nanoparticles. Colloidal CuO particles of 15 nm particle size were developed using hydrothermal synthesis technique. Multiwalled carbon nanotubes (MWCNTs) with surface are 700 m²/g was employed as a substrate for synthesis of CuO-coated MWCNTs using electroless plating. On the other hand, aluminium particles with combustion heat of 32000 J/g is of interest as high energy density material. The impact of stoichiometric nanothermite particles (CuO/Al & Cuo-coated MWCNTs/Al) on shock wave strength of Al/TNT nanocomposite was evaluated using ballistic mortar test. While CuO-coated MWCNTs decreased the shock wave strength by 15%; colloidal CuO enhanced the shock wave strength by 30%. The superior performance of colloidal CuO particles was correlated to their steric stabilization with employed organic solvent. This is the first time ever to report on fabrication, isolation, and integration of stablilized colloidal nanothermite particles into energetic matrix where intimate mixing between oxidizer and metal fuel could be achieved.     

低Ni/改性Al2O3催化剂表面性质表征

本文用氧吸附法和程序升温脱附（ＴＰＤ）法分别考察低Ｎｉ／改性Ａｌ２Ｏ３催化剂的分散度，环已烷和苯的吸附脱附性能。结果表明：该催化剂分散性好，表面至少存在两种吸附中心。苯、环已烷在该催化剂的表面上属于一级可逆吸附脱附过程，催化剂表面能量分布不均匀。     

核磁共振研究溶胀AB-交联聚合物中的分子运动

测定了溶胀的PPU/PSAB 交联聚合物中链段和侧基的13CT1和NOE ,用VJGM模型和三等价位跃迁内旋转、扩散内旋转以及等价、不等价两位置跃迁内旋转模型分析了其中的主链链段运动和侧基内旋转运动 ,求出了主链和侧基的运动相关时间、扩散系数和活化能等参数 .结果表明PS含量对PPU运动的影响极小 ,PS主链运动活化能与PPU含量存在线性关系 .丙烯酸与苯乙烯共聚对PPU的运动几乎无影响     

利用镁金属化学还原法制备多孔Si/Si-O-C负极材料机理研究

以二乙烯基苯和聚硅氧烷为原料经先驱体转化法制备了Si-O-C材料，利用镁金属在惰性气氛保护下高温还原制备了多孔的Si/Si-O-C负极材料。Si/Si-O-C负极材料的首次放电与充电容量分别为547.2和450.7mAh?g-1，第二次放电与充电容量分别为487.4和422.9mAh?g-1，库伦效率分别为82.3%、86.8%，材料具有较好的循环性能。利用X射线衍射(XRD)、能谱分析(EDX)、元素分析和场发射扫描电镜(FE-SEM)分析了多孔Si/Si-O-C负极材料的组成、结构、形貌，从而研究利用镁金属化学还原法制备多孔Si/Si-O-C负极材料的机理。结果表明，镁金属在还原过程中生成MgO和Mg2SiO4等产物，经HCl洗涤后可形成多孔的Si/Si-O-C负极材料。Si/Si-O-C材料中的单质硅分布于多孔的Si-O-C相中，一定程度上可缓解Si在循环过程中产生的体积效应。利用镁金属还原Si-O-C材料制备多孔Si/Si-O-C材料是一种可行的制备方法。