单扫描极谱法测定有机锗(Ge-132)

在 p H2 .0的 K2 SO4 介质中 ,有机锗 (Ge- 132 )在单扫描示波极谱仪上于 - 0 .13V(vs.Ag Cl/ Ag)和- 1.0 5 V(vs.Ag Cl/ Ag)处产生两个还原波 ,其中 - 1.0 5 V(vs.Ag Cl/ Ag)波灵敏、波形好。峰电流与 Ge-132在 1.0× 10 - 5— 5 .0× 10 - 4mol/ L范围内呈良好的线性关系 ,其检出限为 8.9× 10 - 5mol/ L。该方法用于有机锗营养口服液中 Ge- 132的测定 ,结果较好     

新显色剂氯酚偶氮若丹宁光度法测定痕量银

本文研究了新显色剂氯酚偶氮若丹宁与 Ag( )的显色反应。在 p H 4 .3的酸性介质中 ,有适量的表面活性剂吐温 - 4 0存在下 ,Ag( )与试剂生成橙红色配合物 ,最大吸收峰位于 5 30 nm处 ,表观摩尔吸光系数为 1.12× 10 5L· mol- 1 · cm- 1 。该反应灵敏度高 ,选择性较好 ,加入 EDTA作掩蔽剂 ,可消除 Al3+ 、Bi3+、Pb2 +、Fe3+和 Cu2 +等离子的干扰 ,本方法应用于铅锌矿中 Ag( )测定 ,结果令人满意     

氢化物-原子荧光法测定煤中铅

铅是煤中有害元素之一。通常测定的方法有原子吸收法和比色法。原子荧光法测定铅具有简便快速的优点,而且,测定时的再现性良好,因此,很有推广价值。1　仪器及试剂XGY-1011原子荧光仪、286微机、酒石酸、硼氢化钾。2　仪器条件的选择1.原子化条件载气流速:900mL·min-1;炉温:200℃;KBH4浓度:2%KBH4,加入量:5mLKBH4加入时间:6s2.激发条件炉高:7～8mm;灯电流(峰值):100mA3　分析方法　　取煤样0.5克置于烧杯中,先以少量去离子水润湿,再加入15mL1+1盐酸,待片刻再加入5mL硝酸,加盖,低温电热板上加热0.5小时,待溶液近干时,定量加入氧化剂(…     

5—（4—氯苯基偶氮）—8—本磺酰氨基喹啉与钴（Ⅱ）的显色反应及其应用

本文用光度法研究了新显色剂 5 - (4-氯苯基偶氮 ) - 8-苯磺酰氨基喹啉 (CPBSQ)与钴的显色反应和最佳条件。结果表明 ,在 p H 9.5— 11.5范围内及有氯化十六烷基吡啶 (CPC)和硫脲 -酒石酸钾钠存在下 ,Co( )与 CPBSQ形成 1∶ 3的稳定配合物 ,其最大吸收波长为 5 90 nm。依此建立了一种测定 Co( )的新光度法。 Co( )的浓度在 0— 15 .0 μg/2 5 m L 范围内符合比耳定律 ,其摩尔吸光系数为 1.15× 10 5L·mol-1·cm-1。常见离子对 Co2 + 的测定均无严重干扰。本法具有灵敏度高、选择性好的特点。用于 VB12针剂中钴含量的测定 ,相对标准偏差为 0 .5 %— 0 .6 % ,标准加入回收率为 98%— 10 4 %。     

BSA-SDS-Ag聚合物纳米微粒的制备及其水凝胶性质的研究（Ⅰ）

报道了BSA－SDS－Ag聚合物纳米微粒的制备及水凝胶的性质,用X射线衍射（XRD）、透射电镜（TEM）、傅里叶变换红外（FT－IR）光谱考察了这种聚合物微粒的结构,微粒粒径32nm左右,用UV／Vis光谱及SEM考察了冰凝胶的性,表明Ag^ 离子先与BSA产生化学键合,再学原了Ag粒,进行聚合成网状结构的聚合物。     

化学发光法测定水中1-溴-3-氯-5,5-二甲基海因

基于在碱性条件下 (p H 12 .0— 12 .5 ) 1-溴 - 3-氯 - 5 ,5 -二甲基海因与鲁米诺 -过氧化氢体系反应产生化学发光的性质 ,建立了一种测定其含量的新方法。 1-溴 - 3-氯 - 5 ,5 -二甲基海因的浓度在 4 .0× 10 -8— 1.0×10 -6mol/ L范围内与化学发光强度呈良好的线性关系。本方法的线性范围宽 ,灵敏度高 ,检出限为 2 .0×10 -8mol/ L。操作简单、方便。应用于游泳池水中 1-溴 - 3-氯 - 5 ,5 -二甲基海因的测定 ,结果令人满     

液相硫化银纳米微粒的界面荧光和共振散射光谱特性

在阴离子表面活性剂十二烷基硫酸钠(SDS)和硫代乙酰胺(TAA)存在下,Ag 和S2-反应生成较稳定的Ag2S纳米微粒。它在470nm处产生1个较强的荧光峰,在470nm处产生1个共振散射峰。TAA和Ag 浓度对体系荧光强度的影响与此两种物质浓度对共振散射强度的影响一致,随着Ag 浓度(0~8·0×10-5mol·L-1)增大荧光和共振散射光强度均线性增大。实验结果表明,荧光与共振散射之间存在相关性。此荧光为液相Ag2S纳米微粒产生的固液界面荧光。     

88Ni-Fe合金超细微粒的制备、磁性以及热分析

气相蒸发法制备的88at%Ni-Fe合金超细微粒,平均垃径为5一84nm,观察、分析了样品的形貌、结构、成分、磁性、表面吸附以及氧化等,结果表明,做粒晶体结构呈面心立方,晶格常数及成分均接近于块材,表面吸附一层氮气分子,微粒单畴临界尺寸约为37nm,由此算出有效各向异性常数为6.16×10~5erg·cm~(-3),远大于块材,发现样品的居里温度呈现一定分布,并与微粒的尺寸分布及其表面(界面)层有关.     

超重力环境中合成微细晶须碳酸钙及其表征

在利用旋转产生的模拟超重力环境中 ,以Ca(OH) 2 CO2 为反应物系 ,H3 PO4作为晶形控制剂 ,控制气体流量 10 0～ 30 0L/h ,液体流量 6 0 0～ 10 0 0L/h ,旋转床转速 6 0 0～ 12 0 0r/min ,碳化反应温度为 4 0～ 80℃ ,H3 PO4相对于Ca(OH) 2 完全反应所生成CaCO3 质量分数为 5 %～ 30 % ,采用反应结晶法制备出了平均短轴为 80～ 2 5 0nm、长径比为 10～ 2 5的微细晶须碳酸钙 .制备等量的晶须碳酸钙 ,超重力环境中所需碳化时间约为文献值的 1/ 36～ 1/ 18.同时 ,利用TEM、XRD、TG DTA及元素分析等手段对产品粒子进行了表征 .结果表明 ,所合成微细晶须碳酸钙为结晶态 ,文石型含量达到 97.77% ,初始分解温度较常重力场中下降了 4 0 2℃ .     

胶束中的若丹明6G荧光增强和激光行为

使用阴离子表面活性剂十二烷基硫酸钠 (SDS)有效的增强了若丹明 6G染料水溶液的荧光 ,在若丹明 6G浓度分别为 5 47× 10 -7和 5 47× 10 -4 mol·L-1时 ,最大增强比率分别为 1 95和 9 7。在后一浓度下SDS的加入使若丹明 6G染料激光阈值降低 ,能量转化效率提高。不加SDS时的激光阈值功率密度约为 6 5MW·cm-2 ,加入 4 1× 10 -2 mol·L-1的SDS后 ,激光阈值功率密度降为 0 8MW·cm-2 。泵浦光功率密度为 6 5MW·cm-2 时 ,能量转化效率达到 2 5 %。同时还观察到SDS的加入使溶液吸收谱、荧光谱和染料激光发生了红移。对以上现象的物理机制进行了讨论。     

Structural evolution of sol-gel SiO2 heated glasses containing silver particles

SiO₂ based glasses added with nanometric-silver particles have been prepared by the traditional sol-gel process, using the tetraethyl-orthosilicate alkoxide. The Ag particles were prepared using a new method described in this article, the method uses a cementation reaction between Ag ions and an iron electrode. The size of the particles, measured in the dried glass, was in the range of 100-200 nm. The observed structural changes depend on the annealing conditions, such as the annealing temperature, the amount of silver particles and the type of acid (HCl or HNO₃) used to catalyze the hydrolysis/condensation reactions during the sol-gel process. Samples prepared using both acids crystallized into the cristobalite phase after thermal annealing at 800 °C. The amount of SiO₂ crystallized depends on the amount of Ag present in the glass. Samples prepared from solutions catalyzed with HCl acid show the formation of nanometric Ag particles after thermal annealing at 500 °C, these small particles are not observed after similar treatments when HNO₃ is used as the catalytic acid. HCl and Ag₂O form AgCl which is reduced by residual carbon to form Ag ultrafine particles. The diffusion of the reduced Ag spices, which form these particles, is facilitated by the opened structure of the glasses added with Ag, as indicated by IR measurements.     

金属超微粒子-半导体薄膜的光学瞬态响应

利用飞秒脉冲激光和泵浦 探测技术测量了金属超微粒子 半导体复合薄膜Ａｇ-ＢａＯ的瞬态光学透过率随延迟时间的变化曲线，观察到了薄膜对光的吸收漂白现象，并在不到２ｐｓ时间内恢复．该现象是薄膜中金属超微粒子内费密能级附近电子被飞秒激光脉冲激发，产生非平衡电子而经历瞬态弛豫造成的．弛豫主要包括非平衡电子越过超微粒子和周围介质的界面位垒进入周围介质，以及非平衡电子同晶格和界面的散射两种过程．超微粒子粒径的差别会引起非平衡电子弛豫时间的差别 关键词：     

溅射法制备Ag/Ag2O超微粒子的分析

用Ｘ射线衍射、Ｘ射线光电子能谱、透射电子显微镜和差示扫描量热法对溅射法制备的Ａｇ超微粒子的晶体学结构、表面组成、微粒形态和热力学性质进行了分析。结果表明，所制备的微粒为内部为Ａｇ、表面为Ａｇ₂Ｏ的两相微粒，以及单一的Ａｇ₂Ｏ微粒，粒径在１０ｎｍ以上的微粒没有确定的外形，粒径在１０ｎｍ以下的微粒为球形。微粒有不同于块体金属Ａｇ的异常热效应。到４０天时，沉积在碳膜上的Ａｇ，Ａｇ₂Ｏ两相微粒有一部份还原形成了单一的金属Ａｇ超微粒子。 关键词：     

Dynamic templating role of polynaphtalene sulphonate in the formation of silver nanocrystals in aqueous solution

We have used time resolved small angle X-ray scattering (SAXS) for investigating the early stages of the formation of crystalline colloidal Ag particles by AgNO₃ reduction with ascorbic acid in an aqueous acidic solution of a polynaphthalene sulphonate polymer (Daxad). In order to exploit the polymer role in silver crystallization, the measurements have been performed at different polymer concentrations. Data analysis suggests that the nucleation and growth of primary particles of about 20 nm in diameter, occurring in a surface-fractal arrangement of the dynamic polymeric template, is assisted by the development of long range spatial correlations. These correlations could be a sign of polymer-induced liquid fluctuations as intermediate precursors of Ag crystallization.     

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher’s breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher’s breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face velocity), work practices, type and quantity of the material being handled, room conditions, and the adequacy of the room exhaust.

Mechanical properties of Ag added Dy123 low porosity bulks

Mechanical properties of Ag added DyBa₂Cu₃O_x (Dy123) low porosity bulks were evaluated by bending tests of specimens cut from the bulks. The bending strength of the Ag added low porosity bulks was higher than that of a Dy123 low porosity bulk without Ag addition tested in the previous study. No significant difference in the area fraction of Ag particles was observed among the bending test specimens. On the other hand, an increase of the bending strength with decrease of the average Ag particle size was observed. It is deduced that small Ag particles effectively suppress the crack propagation.     

表面修饰对α-Fe2O3超微粒光谱特性的影响

本文用超声分散的方法将α Fe2 O3 超微粒分散于硬脂酸 /正己烷 /氯仿溶液中 ,使α Fe2 O3 超微粒被硬脂酸表面修饰。α Fe2 O3 超微粒被表面修饰后 ,紫外 可见光的吸收边从 392nm移动到 896nm ;红外光谱中的Fe—O键振动峰出现了“红移”现象 ,分别从 52 4 36cm- 1 移动到 52 1 33cm- 1 和从 446 37cm- 1 移动到 443 34cm- 1 ,表面修饰后 ,α Fe2 O3 超微粒X 射线衍射的相对强度明显增大 ,衍射峰位置向衍射角减小的方向移动。     

结晶紫的表面增强共振拉曼光谱和银胶浓度的关系

常用的银胶一般浓度较低且不稳定,这就限制了它在表面增强共振拉曼谱(SERRS)中的应用,本文旨在探讨一种容易制备,浓度高而且特别稳定的银胶在增强结晶紫(CV)SERRS讯号方面的应用,对一定浓度的CV,我们发现只有配合适当浓度的银胶才能获得最强的SERRS的信号,这个现象是由于稳定剂(PVP)在银颗粒表面的作用造成的。     

用于超短激光脉冲检测的新型光电发射薄膜

Ａｇ－Ｂａ－Ｏ薄膜是金属超微位子埋藏于半导体基质中的全新型光电转换薄膜。它不含碱金属，有很好的稳定性，可以在大气中存放，再置入真空系统中不需要激话，就能产生足以检测皮秒级激光脉冲信号的光电子发射。在激光作用下有特殊的灵敏度。这种光电转换薄膜有很好的应用前景。