纳米二氧化钛带宽标准物质的均匀性和稳定性检验

标准物质是具有准确量值的测量标准，主要应用于产品质量控制、设备校准、测试方法和质量仲裁等工作。均匀性和稳定性是标准物质的主要特征，也是对标准物质的基本要求。因此，对标准物质特性量值的均匀性和稳定性进行考察是研制标准物质非常重要的环节。本文以国家纳米科学中心研制的纳米二氧化钛带宽标准物质为实例，对其带宽进行了均匀性和稳定性检验。     

温度对温泉水氧化还原电位的影响

通过对四川5个温泉水质中氧化还原电位的现场测试,得到该温泉水T-Eh变化曲线。利用物理化学原理,采用计算机模拟砷的T-Eh理论变化曲线,结果与实际曲线出现相反的变化趋势。通过研究合理地解释这种现象,同时证明温度对温泉水的氧化还原体系有较大影响,对温泉水中变价元素的测定影响非常严重。     

能力验证样品均匀性和稳定性检验的统计方法

本文介绍了能力验证样品均匀性检验的t检验法、方差分析法、极差检验法、平均值一致性检验法和ASTM E826—1996中的统计方法以及稳定性检验的t检验法。     

基于废水处理工艺的氧化还原电位实验研究

在有机废水处理过程中,发生着多种氧化还原反应,氧化还原电位对整个系统的氧化还原状态起到指示作用。本文将废水处理工艺和ICASB池高度作为研究对象,研究氧化还原电位的变化特性。     

能力验证样品均匀性和稳定性检验的统计方法

本文介绍了能力验证样品均匀性检验的t检验法、方差分析法、极差检验法、平均值一致性检验法和ASTM E826-1996中的统计方法以及稳定性检验的t检验法。     

氧化还原电位测定仪测得值的不确定度分析

本文简单介绍了氧化还原电位测定仪的工作原理,参考了酸度计的校准方法对氧化还原电位测定仪进行校准,并以此建立了测量模型,对氧化还原测定仪的测得值进行了不确定度的分析和评定。     

苯酚标准溶液加碱配置的稳定性研究

在挥发酚分析的4-氨基安替比林分光光度法中,为延长了10.0mg/L的苯酚标准中间液和1.00mg/L苯酚标准使用液的稳定性,在配置的苯酚标准中间液和苯酚标准使用液中加入氢氧化钠使之达到0.02mol/L,以4-氨基安替比林直接分光光度法进行实验研究,发现加碱苯酚标准中间液至少可稳定3个月,加碱苯酚标准使用液至少可稳定2个月,因此,两种标准溶液均无需当天配置。     

真空镀膜稳定性与均匀性研究

真空镀膜的质量受多种因素的影响,镀膜工艺参数等诸多要素直接影响到真空镀膜的稳定性与均匀性。本文以真空蒸发镀膜和PECVD法为例,详细分析了影响镀膜稳定性与均匀性的工艺问题,希望对于实际真空镀膜工作质量的提供有所启发和帮助。     

生化分析仪杂散光标准溶液的研制

根据国家检定规程,研制了生化分析仪检定用杂散光标准溶液。简要介绍了标准溶液的配制方法,重点介绍了标准溶液的均匀性检验、稳定性检验和定值方法,详细分析了标准物质的不确定度。     

浅谈地基均匀性、稳定性评价

地基的均匀性、稳定性评价是各行业工程勘察中的一项重要内容,从定性和定量两方面论述地基的均匀性、稳定性,并提出不均匀地基的基础设计时应采取的结构措施。     

Solubility and solution stability studies of different amino acid prodrugs of bromhexine

Objective: The aim of the present study was to prepare the amino acid prodrugs of bromhexine hydrochloride to improve its solubility.

Methods: All the prodrugs were synthesized by first reacting bromhexine with tert-butoxycarbonyl (Boc) protected amino acid and then deprotection was carried out by using trifluoroacetic acid. These prodrugs were characterized by their melting points, NMR, mass and FTIR spectroscopy. Solubility and partition coefficient of bromhexine and various prodrugs were determined. The solution stability of various prodrugs was also determined in various buffers of pH ranging from 2 to 10. Degradation rate constants and half-life were also determined at various pH.

Results and discussion: The structures of all the synthesized prodrugs were confirmed by NMR, mass and FTIR spectra. The prodrug 2-N-l-alanyl-bromhexine hydrochloride showed maximum solubility and minimum partition coefficient value. These prodrugs may hydrolyze by one or more mechanisms. The order of decreasing rates of hydrolysis was 2-N-l-prolyl-bromhexine hydrochloride > 2-N-glycyl-bromhexine hydrochloride > 2-N-l-alanyl-bromhexine hydrochloride. All the prodrugs exhibited maximum stability in the acidic pH range and undergo base catalyzed hydrolysis.

Conclusion: Solubility studies and partition coefficient values indicated that the synthesized prodrug, 2-N-l-alanyl-bromhexine hydrochloride, was least lipophilic as compared to other synthesized prodrugs. Solution stability studies showed that this prodrug undergo minimum hydrolysis at 37°C. So, it is concluded that 2-N-l-alanyl-bromhexine hydrochloride exhibits better solubility and stability as compared to other synthesized prodrugs.     

氧化还原法制备钨晶须及其生长机理研究

研究了钨晶须的制备工艺,并分析了其生长机理.采用X射线衍射、扫描电镜、能谱分析、透射电镜对制备的钨晶须进行物相、形貌、成分、微观结构的分析和表征.研究表明:钨晶须长度大致在1～10μm,直径在1μm以下,部分达到纳米级;晶须为单晶bcc结构,生长方向为110;钨晶须形成过程为钨粉及其氧化产物与水汽反应生成气相水合物WO2(OH)2,遇氢气还原后形核并沉积,进而定向生长为晶须结构,钨晶须的生成遵循VS机理.     

酸性蚀刻废液制备纳米铜粉及其稳定性研究

以酸性蚀刻废液为铜源,水合肼为还原剂,采用液相还原法制备纳米铜粉.研究发现,在氯离子的存在下,直接还原难以得到高纯度的铜粉.介绍了络合还原和除氯后还原两种铜粉制备方法,用铜粉导电率表征其抗氧化性能,并对两种方法制备的铜粉的稳定性进行了比较分析.     

Structure, Homogeneity and Properties of Thermoelectric Materials Based on Ternary Solid Solutions of Bismuth and Antimony Chalcogenides

Ternary solid solutions Bi_xSb_1-xTe and especially Bi₂Te_1-ySe_y grown by vertical zone melting have the tendency for dendrite liquation. It causes considerable chemical inhomogeneity of the material and multicomponent structure. The effect of long-term annealing at 380–400°C on microstructure, phase composition and properties of structural components has been studied. It was shown that proper growth regime provides ingots with oriented column structure and good texture, which maximizes thermoelectric properties along the growth axis.     

掺镁铌酸锂晶体的光学均匀性和抗光伤性研究

研究了不同Ｌｉ／Ｎｂ克分子比、掺镁铌酸锂（ＭｇＯ：ＬｉＮｂＯ_３）晶体的光学均匀性和抗光伤特性．以二元同成分配比为基础，掺入约５ｍｏｌ％ＭｇＯ的ＬｉＮｂＯ_３晶体显示出高的抗光损伤特性，但光学均匀性较差．根据ＭｇＯ－Ｌｉ_２Ｏ－Ｎｂ_２Ｏ_５三元相关系研究寻找到的三元同成分配比，生长出的ＭｇＯ：ＬｉＮｂＯ_３晶体具有优良的光学均匀性，但其抗光伤能力低．发现当配料组成为Ｌｉ／Ｎｂ＝４７．８／５２．２，而ＭｇＯ的掺入量为５．７ｍｏｌ％时，晶体既具有良好的光学均匀性，也有较好的抗光伤性．     

环境噪声达标区验收抽测方法的探讨

根据对环境噪声达标区验收抽测方法的理论分析和实践经验总结,选择合理的抽样检验方法,在保证验收结果可靠性的情况下,使抽测方案最优化。     

海水pH标准物质的研制

提出一种更适合于海水pH测量的海水pH标准物质,对小批量制备该标准物质的制备方法及其定值方法进行探索研究。采用分光光度测定法测定海水pH标准物质的pH值,对该批海水pH标准物质分别抽取一定数量的样品采用F检验法和t检验法进行了均匀性检验和稳定性考核。结果表明,该批以人工海水为介质的海水pH标准物质混合均匀,常温条件下保存六个月是稳定的。     

Synthesis of Zirconia Nanoparticles in Distilled Water Solution by Laser Ablation Technique

Pulsed laser ablation in liquid （PLAL） has become an increasingly important technique for metals production and metal oxides nanoparticles （NPs） and others. This technique has its many advantages compared with other conventional techniques （physical and chemical）. This work was devoted for production of zirconia （ZrO2） nanoparticles via PLAL technique from a solid zirconium target immersed in a wet environment in order to study the effect of this environment on the optical properties and structure of ZrO2 nanoparticles. The solutions which used for this purpose is distilled water （D.W）. The produces NPs were characterized by mean of many tests such as UV-visible （UV-Vis.）, transmission electron microscope （TEM） and Z-Potential. The UV-Vis. A spectrum has atwavelength is 271 nm. The TEM test shows less than 10 nm average particle sizes with spherical and irregular shapes. Z-Potential test shows value about ＋56.1 mV which indicate for NPs stability with extremely low agglomeration solution.     

公斤工作基准稳定性误差的统计与分析

本文对力学室一等质量实验室的26、27、32三个公斤工作基准砝码的稳定性误差分别作了分析。经过对历年的检定记录和中间核查的分析汇总,得出各个公斤工作基准的稳定性误差,采用多个砝码多次全组合测量,利用最小二乘法计算出这三个公斤工作基准砝码之间的质量差值,找出它们的稳定性误差的变化趋势。     

粒度分布对Cu包覆SiC颗粒相分布均匀性的影响

利用歧化反应原理,在SiC颗粒表面包覆金属Cu.通过俄歇电子能谱(AES),分析粒度分布对Cu包覆SiC颗粒相分布均匀性的影响.SiC颗粒的粒度分布范围过宽,Cu倾向于包覆在大颗粒表面而无法分散到细小颗粒表面.减小粒度分布范围,纳米SiC颗粒同样能被Cu均匀包覆.应当控制纳米SiC颗粒在一个较小的分布范围,以保证理想的Cu包覆效果和两相分散均匀性.