乙二醇法合成稳定纳米银溶胶的研究

硝酸银水溶液缓慢注入较高温(>100°C)的PVP乙二醇溶液中,还原得到不同颜色的纳米银溶胶。实验表明,纳米银溶胶的外观颜色和反应温度与PVP浓度有关;紫外-可见光谱分析表明,该法合成的纳米银溶胶的特征吸收峰在400~500 nm之间,吸收峰位移主要是由纳米银颗粒形貌不同引起的;透射电镜分析表明,纳米银颗粒的形貌是无规则的。     

Li2O—BaO—SiO2系统电极玻璃的研究

测定了Ｌｉ２Ｏ－ＢａＯ－ＳｉＯ２系统的玻璃形成范围和结晶相，得到了等水溶性和等膨胀系统曲线。这些图解指出高化学稳定性和低膨胀系数仅限于高ＳｉＯ２含量区，增加Ｌｉ２Ｏ含量，化学稳定性很快变坏。此外，还研究了玻璃电极的电阻和成分之间的关系。     

有机硅化合物的电解合成和电极反应

本文主要介绍有机硅化合物的电解合成和电极反应的几种方法及其生成物。     

高导电纳米银/聚酰亚胺复合薄膜的制备及其性能研究

通过对聚酰亚胺(PI)薄膜进行碱溶液水解、离子交换和热处理制备出具有表面导电性的聚酰亚胺银复合薄膜,并研究了影响聚酰亚胺银复合薄膜导电性的因素。结果表明,一定的薄膜厚度、碱溶液处理时间、合适的固化时间和固化温度都有利于制备出高导电性的复合薄膜。该复合薄膜保持了聚酰亚胺薄膜的基本力学性能,并且银原子与聚合物之间有良好的黏附性能。该制备方法简单,成本低,易于大规模生产。     

纳米银修饰电极的制备

在圆柱形电解槽中,采用直流电沉积方法在导电玻璃上沉积银纳米材料,制备了Ag／ITO、Ag／CNTs／ITO复合电极,并以制得的复合电极作工作电极,测定两种电极在磷酸缓冲溶液中的循环伏安响应曲线。实验结果表明,纳米银修饰的电极具有很好的电化学活性。     

金属有机化合物的电解合成 电极反应和应用

金属有机化合物是种类繁多的一类有机化合物。近年来由于它的应用越来越广,其重要性也显露出来。它在合成生理活性物质、天然物质和医药农药等中作为催化剂和反应试剂。最近在立体选择合成上用来控制特异反应,并用于新的不对称合成的研究中。近年来还研究用作功能性材料和元件。如何更多更好的合成金属有机化合物是化学化工界的一个重要课题。由于有机电解合成有很多优点,近年来有很多学者在从事金属有机化合物的电解合成研究。     

羧甲基纤维素钠对纳米银导电墨水性能的影响

通过液相化学还原法,以聚乙烯吡咯烷酮（PVP）为保护剂,甲醛为还原剂制备得到粒径为70 nm左右的纳米银溶胶。离心洗涤得到高纯度和高浓度的纳米银水溶胶,添加羧甲基纤维素钠（CMC）及其它助剂后,在超声处理下获得了水基导电墨水。该墨水的Zeta电位值为(-42.8±0.96) mV,表明其具有较高稳定性。用热泡式按需喷墨打印机,在相纸基材上印制导电图案,并在150 ℃下加热处理30 min后,其方块电阻值由处理前的38.48 kΩ骤降至0.87 Ω。撕拉试验表明,加入CMC后的纳米银导电墨水,在基材上有很好的附着力。     

电解行业用环氧导电防腐涂料的制备

以改性环氧树脂为黏结剂、银包玻璃微珠为导电填料合成了导电防腐涂料.分析了不同因素对涂层性能的影响,确定了最佳工艺条件为:w(环氧改性树脂)=30%,w(银包玻璃微珠)=70%(其中银含量为30%),以正丁醇和二甲苯为混合溶剂,烘干温度60 ℃,烘干时间2 h.以该工艺制备的环氧导电防腐涂料具有较好的导电性,与金属、塑料等基体的结合力良好,用于电解行业可减缓金属导电材料的腐蚀.     

溶胶—凝胶法合成发光玻璃陶瓷材料的研究

采用溶胶-凝胶法低温合成了CaO-SiO_2:Eu~(3+),Bi~(3+)发光玻璃陶瓷材料。研究了复杂体系中溶胶-凝胶转变过程,得到了pH值、含水量对胶凝时间、孔隙率、表观密度、比表面积的影响。利用小角X射线散射探讨了溶胶-凝胶转变过程中酸、碱催化的不同机理。通过X射线粉末衍射、红外光谱、热重及差热分析研究了由凝胶至发光晶体的转变过程。通过激发光谱和发光光谱的测试,讨论了材料的发光特性及Bi~(2+)对Eu~(3+)的敏化作用。     

电解合成卤仿的研究：简易电极材料电解氧化合成碘仿（Ⅱ）

本文报道采用镍(Ni)、铅(Pb)、过氧化铅(PbO_2)等材料作为工作电极,在简易电解槽中进行电解氧化合成碘仿(CHI_3)。在不使用电解隔膜的条件下,产率为65—74％。     

Silver Nanoparticle Synthesis via Photochemical Reduction with Sodium Citrate

The aim of this paper is to provide a simple and efficient photoassisted approach to synthesize silver nanoparticles, and to elucidate the role of the key factors (synthesis parameters, such as the concentration of TSC, irradiation time, and UV intensity) that play a major role in the photochemical synthesis of silver nanoparticles using TSC, both as a reducing and stabilizing agent. Concomitantly, we aim to provide an easy way to evaluate the particle size based on Mie theory. One of the key advantages of this method is that the synthesis can be “activated” whenever or wherever silver nanoparticles are needed, by premixing the reactants and irradiating the final solution with UV radiation. UV irradiance was determined by using Keitz’s theory. This argument has been verified by premixing the reagents and deposited them in an enclosed space (away from sunlight) at 25 °C, then checking them for three days. Nothing happened, unless the sample was directly irradiated by UV light. Further, obtained materials were monitored for 390 days and characterized using scanning electron microscopy, UV-VIS, and transmission electron microscopy.     

一种纳米银/聚氨酯复合材料的制备及表征

采用物理方法,将纳米银/聚氨酯杂化材料(nmAg@PU)与具有一定强度的普通聚醚型聚氨酯(PEU)混合制备了新型纳米银/聚氨酯复合材料(nmAg/APU/PEU)。通过红外(FT-IR)、紫外(UV-Vis)、热分析(TGA)、透射电镜(TEM)及差热分析(DSC)对材料进行了表征。结果表明,该复合材料纳米银能够稳定存在,并且未发生明显的团聚,同时与具有高强度的PEU相比,该纳米银/聚氨酯复合材料与PEU的微相分离程度差别不大,该材料有望应用于生物医学材料等领域。     

Chicken Tallow,a Renewable Source for the Production of Biosurfactant by Yarrowia lipolytica MTCC9520, and its Application in Silver Nanoparticle Synthesis

The present study is focused on the production of a biosurfactant using Yarrowia lipolytica MTCC 9520 by employing inexpensive lipid waste, chicken tallow from slaughterhouses. Plackett–Burman and Box–Behnken Design analyses were adopted for preliminary screening of medium variables and further optimization. The maximal yield of 4.4 g L⁻¹ of the biosurfactant was obtained from the optimized medium. The highest emulsification activity was found to be 55%, and the surface tension decreased to 37 mN m⁻¹ at the end of 96 h. The critical micelle concentration of the biosurfactant was calculated as 1.2%. The produced biosurfactant was characterized as cationic lipoprotein in type, and the proteins present in the biosurfactant were observed to have molecular weights between 75 and 100 kDa. The fatty acids composition of the biosurfactant was detected by gas chromatography–mass spectrometry (GC–MS) analysis. Fourier transform infra red (FTIR) and nuclear magnetic resonance (NMR) analysis confirmed the lipoprotein nature of the extracted biosurfactant. Thermogravimetric (TG) and differential scanning calorimetry (DSC) analysis revealed the thermostable nature of the extracted biosurfactant. Surface plasmon resonance vibration peak at 421 nm was observed for the surfactant-stabilized silver nanoparticles (AgNP) through UV–Vis spectrophotometry. The average particle size of the synthesized AgNP was calculated as 7.2 ± 0.4 nm from transmission electron microscopy (TEM) analysis. Energy dispersive x-ray (EDX) spectroscopy exhibited the presence of silver in the synthesized nanoparticles. The zeta potential value of the synthesized AgNP was measured as −22.2 mV, and the polydispersity index was found as 2.3 through dynamic light scattering (DLS) analysis.     

Particle size dependence of the charging of Au nanoparticles immobilized on a modified ITO electrode

Citrate-stabilized gold nanoparticles (Au-NPs) of a nearly spherical shape with four different diameters (3.7, 11.0, 21.7, and 40.8 nm) were immobilized on a 4-aminobutylsiloxane monolayer-modified indium-tin oxide (ITO) electrode. From the results of coulometric measurements using potential step sequences, the number of electrons per particle to be transferred to attain a new equilibrium state after applying a potential step was found to increase in proportion to the square of the diameter. The double layer integral capacitance of the Au-NP surface per unit area in the potential range from −0.4 to 0.6 V (Ag/AgCl/sat’d KCl) is ca. 70 μF cm⁻², being independent of the particle size. The differential capacitance of the Au-NP surface is a function of the potential with a maximum at 0.32 V, while the function is again independent of the particle size. The kinetics of the charging was discussed using the analysis of the potential step transient current. The potential-dependent shift of the plasmon absorption band obtained by constant-potential and potential-modulated transmission-absorption spectroscopic measurements revealed that a smaller Au-NP exhibits a greater blue-shift of the plasmon band when applying more negative potentials, being in line with the Mie-Drude theory.     

利用亲水无规共聚物制备银纳米颗粒及抗菌应用研究

以纯亲水无规共聚物poly（DMAEMA-co-AA）的水相自组装体为模板,研究了其微观纳米自组装体的形貌结构特点,通过原位还原法制备银纳米颗粒,并研究其在抗菌包装中的应用。结果表明,低pH值时,纯亲水无规共聚物poly（DMAEMA-co-AA）形成微孔棒状及棒状的二级自组装体（球状或立方体状）的稳定结构;随着银还原率的提高,银纳米颗粒从球状或立方体状解体为小球状;抗菌薄膜对数抗菌值在4.5以上,用于抗菌包装后常温食品存储时间延长至4倍以上。     

纳米粒子卤化银乳剂的显影过程

采用直接双注法,利用较低分子量的鱼明胶作为保护性胶体介质制备了平均粒径１４．３ｕｍ的卤化银纳米粒子,具有良好的单分散性与热稳定性。利用透射电镜（ＴＥＭ）观测,研究了该纳米粒子乳剂的显影过程;探讨了显影剂组份、显影时间以及明胶含硫氨基酸组份──蛋氨酸（Ｍｅｔ）等对显影银形成与生长的影响;特别揭示了明胶多肽链中具有还原性与卤素受体双重功能的Ｍｅｔ组份对显影银丝的生长具有明显促进作用。表明明胶大分子在纳米卤化银粒子还原形成纳米银丝的过程中的重要地位。     

Effect of ITO electrode on conductance quantization and multi-level cells in TiN/SiOx/ITO devices

In this work, we study TiN/SiO_x/ITO devices to implement conductance quantization and multilevel conductance for high-density memory applications. We observed stepwise conductance with integer and half-integer multiples under pulse and DC voltages. We predict this device's conductance quantization to be a combined result of the formation and rupture of oxygen vacancies in SiO_x film and the formation of O₂^?rich ITO layers due to the oxidation reaction between ITO and SiO_x. Furthermore, it was found that TiN/SiO_x/ITO RRAM devices could stably endure each conductance level.     

氯化甲基汞在ITO电极上的电化学行为及其降解

以氯化甲基汞为代表，对其在ITO导电玻璃上的电化学行为及其降解方法进行探讨。研究了在ITO导电玻璃上氯化甲基汞在不同条件下的降解过程。实验考察了不同扫描速率、支持电解液、溶液酸碱性、外加电压、降解时间等影响因素，结果表明在扫描速率为200mV、外加电压为0．6V、降解时间为30min时，降解率最大的。在上述条件下，发现当氯化甲基汞初始浓度在0～280mmol／L内时，氧化峰电流大小与其成线性关系，线性系数为0．9937。     

葡聚糖存在下微波高压合成银纳米粒子及其光谱特性

以葡聚糖为还原剂和稳定剂,采用微波高压液相绿色合成法制备了黄色银纳米粒子。用吸收光谱和共振散射光谱研究其制备条件的影响。在413nm处产生最大吸收峰,在486nm处产生一个最强共振散射峰。实验表明：该法制备的银纳米粒子粒径均匀,平均粒径为16nm,其稳定性和分散性好,合成方法简便、快捷。