火焰原子吸收法测定钙时磷酸盐的干扰机理研究

通过在钙标准溶液中添加不同浓度的磷酸盐,采用火焰原子吸收法测定钙吸光度的变化情况,探讨钙的原子化效率与待测元素(钙)浓度、干扰物浓度(磷酸根)和二者浓度比例之间的关系,得出火焰原子吸收分光光度法测定钙时磷酸盐的干扰机理是由于磷酸根与钙形成了难挥发的磷酸钙,导致钙在火焰中不能完全蒸发解离,其干扰程度随试样中待测元素钙的浓度变化而变化,并与待测元素钙的浓度和干扰物质磷酸根浓度的比例有关,且磷酸根对钙的干扰不仅影响工作曲线的斜率,而且还影响工作曲线的线性。     

钠钙/铝硅酸盐玻璃疲劳行为研究进展

钠钙硅酸盐玻璃和铝硅酸盐玻璃因高强度和高硬度等优异的物理性能被广泛用于民用和国防军工等领域。疲劳断裂是钠钙/铝硅酸盐玻璃失效的主要形式之一。研究钠钙/铝硅酸盐玻璃的疲劳行为对指导其加工工艺、预测寿命与防止失效具有重要意义。本文综述了硅酸盐玻璃疲劳行为的基本原理、实验方法以及钠钙硅酸盐玻璃和铝硅酸盐玻璃静态疲劳与动态疲劳行为的国内外研究进展,通过对比钠钙硅酸盐玻璃与铝硅酸盐玻璃的疲劳行为发现:钠钙硅酸盐玻璃原片的裂纹萌生门槛值远低于铝硅酸盐原片玻璃的裂纹萌生门槛值,且化学强化钠钙硅酸盐玻璃与铝硅酸盐玻璃的裂纹萌生门槛值均随表面压应力的增大而增大;钠钙硅酸盐玻璃与铝硅酸盐玻璃的裂纹扩展速率均随假想温度的升高而增加,且铝硅酸盐玻璃的裂纹扩展速率随假想温度的变化更大;钠钙硅酸盐原片玻璃与铝硅酸盐原片玻璃的断裂应力均具有加载速率依赖性,而化学强化铝硅酸盐玻璃的动态疲劳断裂应力不具有加载速率依赖性。因此,应力状态和环境因素对化学强化钠钙/铝硅酸盐玻璃静态疲劳与动态疲劳行为的影响将成为未来研究方向。     

ICP-AES同时测定饲料中钙、铜、铁、镁、锰、钾、钠、锌和磷的含量

介绍了应用ICP-AES同时测定饲料中钙、铜、铁、镁、锰、钾、钠、锌和磷的含量。将试料经过高温消化处理后,直接用电感耦合等离子体发射光谱仪测量每个元素的谱线强度,并与同一元素标准溶液的谱线强度比较定量。     

ICP-OES法测定氧化铟锡粉末中微量元素

氧化铟锡(ITO)粉体中的微量杂质元素对其薄膜制品的透光率等光谱特性影响较大。用电感耦合等离子体发射光谱法(ICP-OES)同时测定ITO粉体中Sn,Fe,Cu,Pb,Zn,Ca,Mg共7种微量元素。样品置于银坩埚中用氢氧化钠铺底和覆盖,高温碱法熔融,用热水和稀盐酸浸取并转移至溶液中;选择合适谱线消除了元素之间的谱线干扰、配制混合标准溶液时采用基体匹配法消除了基体干扰;对每种元素的精密度、检出线和加标回收率进行了研究,试验结果表明,每种元素的精密度均不大于1.2%,加标回收率在98~104%之间,样品测试结果与标准值一致。     

减少K_2Cr_2O_7标准溶液浓度误差的方法和分析

在一般化学分析中,玻璃量器引入误差比较小,可以满足要求。但是,在配制用于检定可见分光光度计的 K_2Cr_1O_7标准溶液中,玻璃量器误差是浓度误差的主要来源,本文讨论怎样抓住这个主要矛盾,减小 K_2Cr_2O_7标准溶液浓度误差。     

水中油份浓度分析仪示值误差测量结果不确定度评定

本文依据JJG950-2000《水中油份浓度分析仪》检定规程,介绍了水中油份浓度分析仪示值误差测量结果不确定度的评定方法,对配制标准溶液(区别与直接用标准溶液进行检定)所使用的玻璃量器所引入的不确定度分量进行了分析和评定。     

CIGS双梯度带隙吸收层的制备及特性

采用脉冲激光沉积(PLD)方法,在钠钙玻璃上沉积不同Ga含量的CuIn(1-x)Gax Se2薄膜,研究不同Ga含量对CIGS薄膜结构及光学特性的影响。研究表明:随着Ga含量增加,CIGS薄膜的光学带隙增大。优选特性较好的CIGS沉积在同一个钠钙玻璃衬底上,使Ga/(In+Ga)比在薄膜内纵深方向呈先减小后增加的变化。采用XPS逐层刻蚀分析薄膜的元素组成,利用带隙近似公式得到能带随深度变化情况,最终得到结构、光学特性和电学特性较好的双梯度带隙结构薄膜。     

玻璃表面涂层及甲基红指示剂对121℃玻璃颗粒耐水性试验的影响

随着我国酒类、食品和药品等行业的快速发展,对玻璃瓶的需求变大,质量要求也越高。因此对玻璃容器的材质化学稳定性考察,也越来越重要。本文选取有涂膜及未涂膜的钠钙玻璃模制瓶为研究对象,分别使用YBB00252003-2015和GB/T 12416.2-1990标准中所提及的两种不同配制方法的甲基红指示剂进行121℃玻璃颗粒耐水性试验,比较两种甲基红指示剂以及表面涂层对试验结果的影响。     

ICP-AES法同时测定水中钾、钠、钙、镁的研究

本文采用美国Perkin--Elmer公司电感耦合等离子发射光谱仪(Optima 4300DV),对同时测定水中的钾、钠、钙、镁四种元素的最佳测试条件进行了探讨,研究了元素间的干扰情况,并进行了检出限、准确度、精密度试验,结果均可满足要求。     

ICP-AES法同时测定水中钾、钠、钙、镁的研究

本文采用美国Perkin-Elmer公司电感耦合等离子发射光谱仪(Optima 4300DV),对同时测定水中的钾、钠、钙、镁四种元素的最佳测试条件进行了探讨,研究了元素间的干扰情况,并进行了检出限、准确度、精密度试验,结果均可满足要求。     

Determination of iron, cobalt, copper, zinc, rubidium, molybdenum, and cesium in human serum by inductively coupled plasma mass spectrometry

A method was developed for the determination of seven trace elements (Fe, Co, Cu, Zn, Rb, Mo, and Cs) in human serum by inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation was kept as limited as possible. As the only sample pretreatment serum samples were diluted with nitric acid and indium was added as an internal standard. The results for iron, cobalt, copper, and zinc were corrected for interferences from polyatomic ions by using a blank solution containing the same concentration of sodium, sulfur, chlorine, and calcium as human serum. For copper and zinc the corrections are small, whereas for iron and cobalt they are important. No interferences occur for the considered isotopes of rubidium, molybdenum, and cesium. In order to test the accuracy and precision of the analytical technique, a "second-generation biological reference material (human serum)" was analyzed. The results obtained by ICP-MS for the seven elements considered showed good agreement with the certified values.     

Pozzolanic reaction of glass powder and its role in controlling alkali–silica reaction

It is well recognized that finely ground soda-lime glass exhibits high pozzolanic reactivity. Fine glass grains will not undergo an Alkali-silica reaction (ASR) in the presence of alkali, and can even mitigate the ASR between alkali and reactive aggregates. Influences of the pozzolanic reaction of glass powder on solid phases, pore solution in cement paste, and the ASR mitigating effect are investigated in the study. The pozzolanic reaction of glass not only consumes portlandite to form in-situ C-S-H, which appears as reaction rim around glass grains, and precipitated C-S-H, but also reduces monosulfate level. The impacts of the pozzolanic reaction on species in pore solution are characterized by increased aluminum, sulfate, sodium, and silicon concentrations and decreased calcium concentration. The increase in aluminum and sulfate concentrations results from the decrease in solid monosulfate. Glass powder controls ASR by increasing aluminum concentration in pore solution to reduce the dissolution of amorphous silica from reactive aggregates.     

Alkali oxide containing mesoporous bioactive glasses: Synthesis,characterization and in vitro bioactivity

We report, for the first time, the synthesis of sodium oxide containing mesoporous bioactive quaternary glasses and compared with two different mesoporous ternary silicate systems by modified sol–gel process. With the aid of three different glass systems, a systematic analysis has been made on phosphorous-bearing (P-bearing) and phosphorous-free (P-free) mesoporous bioactive glasses to investigate the role of phosphorus on in vitro bioactivity of various silicate glasses with constant alkali oxide content. The combined use of multiple analytical techniques XRD, FTIR, SEM, nitrogen adsorption/desorption analysis before and after soaking in the SBF solution allowed us to establish strong correlation between composition, pore structure and bioactivity. We find that the P-bearing mesoporous glasses show the rapid hydroxycarbonate apatite (HCA) crystallization than P-free mesoporous glasses independent of calcium content. The present study reveals that the presence of phosphorous jointly with calcium in the bioactive glass system significantly enhances the rate of apatite formation as well as crystallization of apatite phase. Additionally, we find that a glass with sodium orthophosphate rich phase enhances the solubility when immersed in SBF and further accelerate the kinetics of apatite formation. The influences of the chemical composition and their superior textural properties on bioactivity are explained in terms of the unique structure of mesoporous bioactive glasses.     

An examination of the reactivity of fly ash in cementitious pore solutions

Fly ash is frequently used to replace cement in concrete, but it is difficult to predict performance based only on the oxide composition, which is typically the only compositional information available. In order to better utilize fly ash in concrete, it is important to develop more meaningful characterization methods and correlate these with performance. The research presented here uses a combination of analytical methods, including X-ray powder diffraction, scanning electron microscopy coupled with multispectral image analysis, and solution analysis to determine the compositions of the glassy phases in a specific fly ash and to examine the fly ash’s reactivity in late- and early-age cement pore solutions, ultrapure water, and sodium hydroxide. The dissolution of individual glassy phases in the fly ash was tracked over time and the precipitation of reaction products monitored. A high-calcium aluminosilicate glass was the most reactive, a low-calcium aluminosilicate glass was of intermediate reactivity and a medium-calcium aluminosilicate glass had the lowest reactivity in the solutions tested for a specific fly ash. This result suggests the glass composition has a strong effect on reactivity, but that that there is not a strict correlation between calcium content and glass reactivity.     

TiO2光催化薄膜的XPS研究

利用ＴｉＯ２溶胶通过浸涂技术在钠钙玻璃表面制备了ＴｉＯ２光催化薄膜,根据Ｘ射线光电子能谱（ＸＰＳ）对薄膜进行了表征。结果表明,薄膜中除含有＋４价Ｔｉ的氧化物外,还有一定量的＋３和＋２价Ｔｉ的氧化物。结合有机基团燃烧的还原作用、玻璃中钠与钙离子的扩散和Ａｒ离子刻蚀,对这种现象作了讨论。Ｏｌｓ的高分辨谱比文献报道的更复杂。元素在薄膜内层的分布更均匀,从表面到内层,Ｏ和Ｔｉ元素的含量明显增加,而Ｃ、Ｎａ     

Reaction of sodium calcium borate glasses to form hydroxyapatite

This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO · 2Na₂O · 6B₂O₃ or 2CaO · 2Na₂O · 6B₂O₃ glass and a 0.25 M phosphate (K₂HPO₄) solution at 37, 75 and 200 °C. Glass samples in the form of irregular particles (125–180 μm) and microspheres (45–90 and 125–180 μm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K₂CO₃) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO · 2Na₂O · 6B₂O₃), or reacted at an elevated temperature (75 °C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 °C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape.     

测定饲料及其原料中钙的方法改进

本文提出了在测定不同饲料及原料中钙含量的改进方法对含磷样品,采用三乙醇胺和洒石酸盐作掩蔽剂,进行 EDTA 滴定分析,而对含重金属离子的样品而言,则需添加氰化钾及盐酸羟胺,以消除重金属离子的干扰。     

Studies of chemical interferences in an inductively coupled plasma using moment analysis of space-resolved emission profiles

Interelement effects induced by sodium, aluminum, and phosphate ion on calcium and magnesium emission were studied with a two-channel spectrometer that could record spatially resolved emission profiles of an atom line and an ion line simultaneously. The statistical moments of the digitized emission profiles were calculated and were employed for rate-constant estimation using our previously established theory. Interelement effects are results of interferences in the analyte atomization, ionization, and/or recombination steps. Characteristic changes will be induced in the emission profiles by each of these interferences. These changes can be characterized by the statistical moments of the corresponding profiles. Therefore, by investigating variations in the rate constants caused by the specific concomitant, one may better understand the analyte atomization-excitation mechanisms. Sodium enhances the atomic emission of both calcium and magnesium but has little effect on their ionic emission. Based on the trends of variation in the rate constants, the atomic signal enhancement seems to be attributed more to the facilitation of analyte atomization rather than to the shift of ionization equilibrium. Aluminum and phosphate ion appear not to induce significant interferences on either elements.     

Lead and copper removal from aqueous solutions by porous glass derived calcium hydroxyapatite

A porous glass was prepared by sintering Na₂O-CaO-B₂O₃ glass powder with powdered sodium chloride. Subsequently, the sodium chloride was dissolved in water resulting in a highly porous material. A sample was prepared consisting of 60 vol% glass and 40 vol% salt which both had particle sizes <100 and 400-500 μm, respectively. The sample was sintered at a temperature of 580 °C for 15 min which resulted in an optimum structure with 57.5% porosity and 0.944 MPa compressive strength. Amorphous calcium hydroxyapatite was formed by immersing these materials in 0.1 M K₂HPO₄ solutions at room temperature for 1 day. The porous glass derived hydroxyapatite matrix was then processed for removing lead and copper ions from aqueous solutions. The results showed that the glass derived calcium hydroxyapatite matrix effectively immobilizes lead and copper ions in solution. The adsorption mechanism was investigated by the X-ray Diffraction (XRD) and Scanning Electron Microscopy including Energy Dispersive X-Ray Spectrometry (SEM-EDX).     

Influence of sodium oxide content on bioactive glass properties

The rate of in vivo degradation and level of bioactivity of bioactive glasses are composition dependent [1]. By altering bioactive glass composition, the rate of resorption can be controlled. The network connectivity of a glass can be used to predict various physical properties of the glass including its solubility and, hence, its bioactivity [2]. Glass solubility increases as network connectivity is reduced. Glasses in the soda-lime phosphosilicate system were studied. The initial choice of composition was based on phosphate content and low network connectivity. A systematic substitution of calcium oxide for sodium oxide on a molar basis was made in order to examine the influence of sodium oxide content on the glass properties while keeping the network connectivity constant. The glass transition temperature and the peak crystallization temperature were seen to decrease linearly with increasing sodium oxide content. Thermal expansion coefficient and glass density were also seen to be related to sodium oxide content. Preliminary in vitro biocompatibility studies revealed that the glasses of higher sodium oxide content were associated with a cytotoxic response. The measurement of media pH indicated that this cytotoxic effect was due to ion exchange reactions at the glass surface.