基于激光诱导荧光技术的蒽检测系统

介绍了一种用Nd：YAG的三倍频（波长355nm）作为激发光,CCD作为探测单元,加上其他光学元件构成的激光诱导荧光检测系统,并测量了蒽的乙醇溶液的荧光光谱。分析了荧光强度与蒽溶液浓度的关系。实验结果表明,蒽溶液浓度在0．003～0．700mg／L范围内与荧光强度有良好的线性关系,相关系数为0．9987,检出限为1．3ng／mL,蒽的回收率在98％～106％范围内。系统适合用于蒽的激光诱导荧光检测。     

火花源质谱法测定高纯稀土氧化物中的痕量稀土杂质

本工作用火花源质谱法研究了高纯稀土氧化物(Y_2O_3、Eu_2O_3、Tb_4O_7)中痕量稀土杂质的定量分析方法,检测下限为O.06～0.6ppm。本研究还用理论相对灵敏度因子计算了稀土杂质的含量,结果与由实验相对灵敏度因子求得值基本吻合。     

用于纳升级微量样品检测的原位激光诱导荧光系统

针对生命科学研究中测试样品量极少的关键问题,以毛细管作为样品检测池,采用入射光与荧光原位进出的系统设计方案;以半导体泵浦固体激光器作为激发光源、高分辨紧凑型光谱仪作为探测器,构建了用于纳升级微量样品检测的原位激光诱导荧光系统。利用水溶液中罗丹明B浓度的测量来验证系统性能。结果表明,罗丹明B浓度在93pg/mL～15ng/mL范围内与荧光强度有良好的线性关系,相关系数为0.9982,检出限为28pg/mL,证实该系统具有低噪声、低试剂消耗、低检出限、高灵敏度和精确度等优点,可满足生物测试的实际使用要求。     

LED诱导叶绿素荧光光谱检测系统的设计

为实现叶绿素浓度的快速、无损、定量检测,通过对叶绿素荧光现象的分析和研究,选择了合适的激发光源、光谱分析仪器,设计了相应的光路系统,获取叶绿素的荧光光谱。采用相对荧光强度F675和荧光强度比F685/F735分别与水体和叶片中的叶绿素含量,建立回归预测模型,实验结果表明,该系统可进行叶绿素含量的相关检测,且操作简单,具有较好的灵敏度和准确度,但需要对不同的植物种类建立不同的回归预测模型。     

X荧光光谱法测定银矿石中的主次元素

采用粉末压片制样,通过顺序扫描型波长色散X荧光光谱仪快速测定内蒙古自治区银矿石中的Ag、Ga、S、Cu、Pb、Zn等主次元素,通过对方法的仪器条件进行对比,最终确定最佳条件。对国家标准物质测定结果的精密度进行讨论,方法测定数据令人满意。     

光纤嵌入式激光诱导荧光检测系统研究

针对传统的激光诱导荧光检测系统难于实现微型化和集成化的缺点,本文设计并组装了光纤嵌入式激光诱导荧光检测系统,从检测距离、分离电压和样品浓度几个方面分析了系统的性能.实验结果表明,该系统具有结构紧凑、操作方便、灵敏度较高等优点.     

锁相相关检测技术在荧光光纤温度传感器中的应用

用激光加热基座法生长出端部掺Cr3+的YAG(Y3Al5O12)光纤荧光温度传感头,采用锁相相关检测技术对呈指数衰减的荧光寿命进行测量.在0～180℃测温范围内,测量误差为0.4℃,主要由信号处理电路引起.与其他的相敏检测技术相比,锁相相关检测提高了系统测量精度和抑制噪声的能力.系统动态响应好,抗电磁干扰,可应用于生物医疗和变电站等场所的温度监控.     

辉光放电质谱法测定高纯锑中的痕量杂质元素

采用辉光放电质谱法 ( GDMS)对高纯半导体材料锑中的 Mg、Si、S、Mn等 1 4种痕量杂质元素进行测量。对仪器工作参数进行了优化选择 ,并对杂质浓度与溅射时间的关系、质谱干扰对测量的影响及测量的准确性和重现性进行了探讨。实验表明 :样品经足够长时间的溅射 ,可以消除样品制备和处理过程中的表面污染 ,可以为其它高纯材料的检测提供可靠的科学依据。辉光放电质谱法是检定高纯半导体材料的理想工具     

X射线荧光光谱法快速半定量分析催化剂中的稀土总量

介绍了用X射线荧光光谱仪测量催化剂中稀土总量的快速半定量分析方法。该方法根据自然界中稀土元素丰度与稀土总量之间的关系，通过选择镧、铈两个元素作为指示元素进行测定，就可以基本确定稀土元素的总量。实验结果证明，该方法快速简便、工作效率高。测量结果与给出的参考值吻合较好。     

蛋白质／多肽的毛细管电泳-激光诱导荧光检测分析方法发展

毛细管电泳（CE）与激光诱导荧光检测器（LIF）联用为蛋白质／多肽类样品提供了一种快速、灵敏的分析方法。选择并开发合适的荧光衍生化试剂,建立并优化相应的衍生、分离过程,使用并发展高性能、低成本的激光诱导荧光检测器件是实现高效分离、高灵敏度检测的有效途径。本文将各荧光衍生化试剂以激发光源归类,在探讨常用荧光衍生化试剂特性的基础上,对近几年蛋白质／多肽类样品的毛细管电泳-激光诱导荧光分析方法发展加以系统综述。     

高纯金属铕及其氧化物中14个稀土杂质的ICP-MS测定

本文针对单同位素元素铥与氧化铕基体的氧化物离子的质量数重叠,在ICP-MS谱法中无法测定的问题,研究了P_(507)萃淋树脂小型柱分离。在试验选择的分离条件下,分离周期(进样-淋洗-洗脱-再生)为2.5h。结合直接测定大部分稀土杂质,最终建立了高纯铕中14个稀土杂质元素的ICP-MS分析方法。方法测定下限(ΣRE)<5μg/g,加标回收率在92～111％范围内,RSD％<10％。方法灵敏、快速、简便,满足4～5N高纯金属铕及其氧化物产品分析的要求。     

Influence of Er:YAG laser frequency on dentin caries removal capacity

The purposes of this study were to evaluate in vitro the influence of different frequencies of Er:YAG laser on the human dentin caries removal capacity. Thirty fragments obtained from third molars were randomly assigned into three groups (n = 10) according to the laser frequency used: 4, 6, and 10 Hz. The caries lesion (±1 mm deep) was induced before the irradiation by S.mutans cultures for 6 weeks. The specimens of all groups were irradiated with 200 mJ of energy in noncontact and focused mode under constant refrigeration (water flow: 2.5 mL/min). Quantitative analysis of the caries removal was performed by DIAGNOdent^TM and the Axion Vision^TM software. Qualitative analysis was performed by Scanning electron microscope (SEM) and light microscope (LM). Data were analyzed by ANOVA and Fishers' tests. The DIAGNOdent^TM revealed that the caries removal was similar with 4 and 6 Hz and was superior with 10 Hz (P < 0.05). The analysis with Axion Vision^TM software revealed that the caries removal was similar with 6 and 10 Hz and the 4 Hz group promoted the lowest caries removal. Through SEM morphologic analysis, some specimens irradiated with 4 Hz presented, under the demineralized dentin, a disorganized collagenous matrix. The LM images revealed that all frequencies used promoted irregular caries removal, being observed over preparations with 6 and 10 Hz. It can be concluded that the increase of Er:YAG laser frequency provided a higher dentin caries removal without selectivity to the disorganized dentin. Microsc. Res. Tech., 2010. © 2010 Wiley‐Liss, Inc.     

Thermal effects and morphological aspects of human dentin surface irradiated with different frequencies of Er:YAG laser

This study reports the effects on micromorphology and temperature rise in human dentin using different frequencies of Er:YAG laser. Sixty human dentin fragments were randomly assigned into two groups (n = 30): carious or sound dentin. Both groups were divided into three subgroups (n = 10), according to the Er:YAG laser frequency used: 4, 6, or 10 Hz (energy: 200 mJ; irradiation distance: 12 mm; and irradiation time: 20 s). A thermocouple adapted to the tooth fragment recorded the initial temperature value (°C); then, the temperature was measured after the end of the irradiation (20 s). Morphological analysis was performed using images obtained with scanning electron microscope. There was no difference between the temperatures obtained with 4 and 6 Hz; the highest temperatures were achieved with 10 Hz. No difference was observed between carious and sound dentin. Morphological analyses revealed that all frequencies promoted irregular surface in sound dentin, being observed more selectively ablation especially in intertubular dentin with tubule protrusion. The caries dentin presented flat surface for all frequencies used. Both substrates revealed absence of any signs of thermal damage. It may be concluded that the parameters used in this study are capable to remove caries lesion, having acceptable limits of temperature rise and no significant morphological alterations on dentin surface. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Microtensile strength of resin cement bond to indirect composite treated by different output powers of Er:YAG laser

The study aimed to evaluate the effect of different output powers of Er:YAG laser on microtensile bonding strength of indirect composite to resin cements.36 indirect composite blocks (GC Gradia DA2, Japan) size 15 × 10 × 10 mm³ were constructed, and divided into 12 groups, as follows:G1: control group (no treatment); Groups G2 to G6: treated with Er:YAG laser (2,940 nm) in noncontact mode, frequency 20 Hz, pulse duration 470 µs, with output power ranging from 2W to 6W; Groups G7 sandblasting, Groups 8 to G12: as Groups G2 to G 6 with preparatory sandblasting. One specimen from each group was analyzed by SEM; each specimen was fixed to a specialized metal jig using cyanoacrylate (Mitreapel, Beta Kimya San. Ve TIC, Iran) and debonded under tension with a universal testing machine (Zwick, Germany) at a crosshead speed of 0.5 mm min^?1. Sandblasting and laser can improve bond strength above an energy level of 150 mJ. SEM evaluation of laser‐treated specimens showed irregularities and deep undercuts. T test analysis showed no significant difference between sandblasted and non‐sandblasted group, with laser output power of 0, 100, or 150 mJ (P = 0.666, P = 0.875, and P = 0.069); in the specimens irradiated with energy output of 200, 250, or 300 mJ, sandblasted specimens showed higher bond strength than non‐sandblasted ones. The results demonstrate that, in composite resin irradiated with laser at energy output of 200–300 mJ, sandblasting might be a suitable procedure to enhance bond strength of resin cement. Microsc. Res. Tech. 79:328–333, 2016. © 2016 Wiley Periodicals, Inc.     

Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel

Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty‐eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm²), 200 mJ (25.5 J/cm²), and 300 mJ (38.2 J/cm²), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before‐irradiation, after‐irradiation, and after‐acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low‐vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser‐induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after‐irradiation undesired effects. Microsc. Res. Tech. 77:410–414, 2014. © 2014 Wiley Periodicals, Inc.     

Analysis of the interfacial micromorphology of adhesive systems in cavities prepared with Er,Cr:YSGG, Er:YAG laser and bur

The purpose of this in vitro study was to evaluate the interaction pattern of adhesive systems on laser and bur cavities. Cavities were prepared according to the following groups (n=9): (G1) conventional diamond bur (No. 1013); (G2) Er:YAG laser (250 mJ, 4 Hz, 80.6 J/cm2); (G3) Er,Cr:YSGG laser (3.5 W, 20 Hz, 61.7 J/cm2). After cavity preparation, specimens were divided into three subgroups differing the adhesive systems used (n=3): (GA) AdheSE; (GB) Clearfil standard error (SE) Bond; (GC) Single Bond. After insertion of a micro-hybrid composite resin, the specimens were sectioned across the bonded surface dividing the teeth into two halves, which were prepared for SEM analysis. Cavities prepared with laser appeared to be more irregular than the bur cavities. Different patterns of gap formation and resin tags could be observed, showing the differences, advantages, and disadvantages of both types of cavities. Under the settings of the present study, resin tags were more pronounced in lased dentin than bur prepared dentin independently of the bonding systems used. On the other hand gap formation between dentin and resin in laser prepared cavities was observed suggesting collagen alteration.     

SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance

BACKGROUND: Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. PURPOSE: To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). METHODS: Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. RESULTS: Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. CONCLUSIONS: Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.     

电感耦合等离子体-质谱法测定茶叶中稀土元素及其不确定度的评定

以In、Rh、Re为内标校正体系,采用微波消解-电感耦合等离子体-质谱法对茶叶样品中16种稀土元素进行同时测定,通过加标回收试验,建立了茶叶样品中稀土元素含量的ICP-MS分析方法.测定16种稀土元素的相对标准偏差均小于10%,加标回收率为89.6%～110.2%.实验表明,该方法不但操作简便快速,而且具有灵敏度高、检出限低、重现性好等优点.举例说明了测量不确定度的评定程序.