电双稳薄膜阻抗转变机理研究

采用真空蒸发的方法交替沉积Ag和TCNQ分子制备了Ag TCNQ金属 有机络合物薄膜 ,并研究了多种外加电压激发下膜的电阻转变特性。发现在转变过程中存在着一种能量效应 ,即当外电压超过某一阈值后 ,完成转变的能量不变。对此现象的可能解释是薄膜内分子在一定的外部电场能量诱导下发生重排 ,致使电导率发生跃变     

All Ag Nanoparticles Are Not the Same: Covalent Interactions between Ag Nanoparticles and Nitrile Groups Help Combat Drug- and Ag-Resistant Bacteria

Antimicrobial resistance has long been viewed as a lethal threat to global health. Despite the availability of a wide range of antibacterial medicines all around the world, organisms have evolved a resistance mechanism to these therapies. As a result, a scenario has emerged requiring the development of effective antibacterial drugs/agents. In this article, we exclusively highlight a significant finding reported by Zbořil and associates (Adv. Sci. 2021, 2003090). The authors construct a covalently bounded silver-cyanographene (GCN/Ag) with the antibacterial activity of 30 fold higher than that of free Ag ions or typical Ag nanoparticles (AgNPs). Ascribed to the strong covalent bond between nitrile and Ag, an immense cytocompatibility is shown by the GCN/Ag towards healthy human cells with a minute leaching of Ag ions. Firm interactions between the microbial membrane and the GCN/Ag are confirmed by molecular dynamics simulations, which rule out the dependence of antibacterial activity upon the Ag ions alone. Thus, this study furnishes ample scope to unfold next-generation hybrid antimicrobial drugs to confront infections arising from drug and Ag-resistant bacterial strains.     

STUDY OF INTERFACES AND SURFACES OF YBa_2Cu_3O_(7-x)-Ag

Interfaces and surfaces of YBa_2Cu_3O_(7-x)(YBCO)-Ag have been studied by SEM-EDXand AES.No effect of Ag on 123 structure in X-ray diffraction pattern was observedfor 0.4 mol Ag doped YBCO.AES analysis indicated that Ag segregated on surfaceof YBCO and resulted in decrease of YBCO-metal lead resistance.In addition,solutionand segregation of Ag as elemental state were often appeared on interfaces and surfacesof high temperature annealed YBCO,whether elemental Ag or compound Ag_2O andAgNO_3 adopted as doping material.     

银基氟化镁材料的研究

采用粉末冶金的方法制备了银基氟化镁材料。利用X射线衍射仪、金相显微镜和差热分析仪等对其组织结构进行分析，同时对其硬度、电导率、密度和摩擦系数等进行了测试。结果表明：形成的合金相对密度达98％以上，银与氟化镁能达到原子级别的结合：在银中添加氟化镁，样品的电导率有较大幅度的下降，并且晶粒显著细化，但材料的硬度提高不大，对银和铜的摩擦系数没有明显的降低。因此，氟化镁不能作固体自润滑材料的添加剂。     

半导体硫化银纳米管的制备与光学性能

在以Triton X-100为表面活性剂形成的反相胶束体系中,成功地制备了半导体硫化银纳米管,管径88 nm～120nm、长度大于2.6 μm.X射线衍射测定表明,产物为纯单斜结构.紫外-可见光谱在275 nm处发现新的吸收峰,最大发射波长与体相材料相比,蓝移了38 nm.     

贵金属Cu、Ag、Au的电子结构和物理性质

由纯金属单原子理论(OA)确定了面心立方结构(FCC)贵金属Cu、Ag、Au的电子结构依次为[Ar](3dn)5.58(3dc)4.21(4sc)0.23(4sf)0.98、[Kr](4dn)4.87(4dc)4.56(5sc)0.66(5sf)0.91、[Xe](5dn)4.20(5dc)4.90(6sc)1.57(6sf)0.33,并确定了Cu、Ag、Au的密排六方结构(HCP)和体心立方结构(BCC)两种初态特征晶体和初态液体的电子结构。根据自然态的电子结构定性解释了熔点、拉伸强度、维氏硬度、体弹性模量、电导和热导率物理性质差异与电子结构的关系,定量计算了晶格常数、结合能、势能曲线及线热膨胀系数随温度的变化。根据非自然态的电子结构,定性解释了晶体结构BCC和HCP的关系。     

少量Ag对低Cu／Mg比的Al—Mg—Cu—Li合金组织与性能的影响

通过显微硬度测试、拉伸试验、能谱分析、SEM及TEM观察，研究了少量Ag对低Cu／Mg比的Al-Mg-Cu-Li合金微观组织与性能的影响。实验结果表明：Ag的添加提高了该合金的硬度和强度，同时改善了其塑性，并延缓了过时效的发生。微观组织观察表明：Ag的添加促进Z相的均匀弥散析出，同时抑制了S＇相在缺陷处非均匀析出；并且Ag的添加还促使了时效初期合金中δ’相的细化和弥散分布，延缓了δ’相的长大。同时分析了析出相种类对合金塑性的影响。     

Ag/CeO2-ZnO催化剂上甲醇部分氧化制氢气研究

研究了用于甲醇部分氧化制氢气反应的Ag/CeO2-ZnO催化剂的制备条件以及反应条件对催化剂性能的影响.Ag/CeO2-ZnO催化剂中银含量、焙烧温度、反应温度以及反应气的比例等对催化剂性能具有很大的影响.Ag/CeO2-ZnO催化剂的制备条件以及反应条件控制在一定范围内时,Ag/CeO2-ZnO催化剂对甲醇部分氧化制氢气具有很高的催化活性与选择性.     

(Ag)_核·(Au)_壳复合纳米粒子的制备

以银原子团簇作晶种,采用微波高压液相合成法制备了分散性好、规则球形的(Ag)核·(Au)壳复合纳米粒子。研究了(Ag)核·(Au)壳复合纳米粒子的紫外可见吸收光谱和共振散射光谱特性。结果表明,液相(Ag)核·(Au)壳复合纳米粒子和高压微波合成的液相金纳米粒子的最强共振散射峰均在580nm处,它们的吸收光谱图相似,最大吸收分别在518.5nm和524.8nm。     

Synthesis of the Silver Nanofluid by ASNSS Process

Arc Spray Nanoparticle Synthesis System (ASNSS) has been used to prepare the silver nanofluids in this study. The metal electrodes under the electrical discharge will melt and evaporate rapidly and condense to form the nanoparticles in the dielectric fluid at lower temperature and produce the suspended nanoparticle fluid. Thus, the mechanism of the ASNSS process is superheating the electrodes by plasma to form metallic nuclei and supercooling these nuclei by dielectric liquid to produce nanofluid. This study considers the different controlling parameters such as discharge current,discharge voltage, pulse-duration time, electrode diameter, and the temperature of dielectric liquid. The optimally operated parameters can be obtained to produce the finer particle size in nanofluid. The results indicate the silver electrodes in alcohol fluid will produce the spherical nanosilver particles. The mean particle size of silver in different dielectric liquid temperatures of-40, -20, 0, and 10℃ is about13.4, 15.8, 17.5, and 21.6 nm, respectively. This indicates that the well suspended fluid can be obtained by controlling the lower dielectric fluid temperature.