活化分析方法的新进展

近几年来,活化分析方法取得了引人注目的进展。在所用活化束流源的种类、辐照和测量条件的最佳化、数据获取和分析结果可靠性的提高以及应用范围的展宽等方面,都进行了卓有成效的探索。本文将简要评述在放射化学中子活化分析(RNAA)、仪器中子活化分析(INAA)、瞬发γ中子活化分析(PGNAA)、超热中子活化分析(ENAA)、快中子活化分析(FNAA)、仪器光子活化分析(IPAA)和带电粒予沂化分析(CPAA)中的最新进展。     

国内声学仪器的现状和展望

一、前 言 声学仪器(包括声和振动的测量仪器)的应用范围相当广泛,它可渗透到各行各业.在冶金、航天、动力机械、地质、地震、医学等方面,对系统的动态分析,对现场的实时信号分析以及大量的建模工作,系统的标准检验、仪表的校准和参数测定,都需要用声学仪器进行时域上系     

基于波谱技术的茶树生长与茶叶品质信息快速检测研究进展

波谱技术快速获取茶树生长和茶叶品质信息对提高茶叶生产信息化、产业化水平,保障茶叶品质和安全具有重要意义。阐述了波谱技术在茶树生长和茶叶品质信息快速检测的研究进展和发展趋势。重点介绍了红外光谱,荧光光谱、拉曼光谱、质谱等在茶树生长信息获取(氮、叶绿素、病虫害信息等)、茶叶品种分类、茶叶分级、茶叶内部品质检测(茶多酚、儿茶素、咖啡碱、氨基酸、农药残留等)、茶饮料和加工品的品质检测以及相关检测设备等方面的研究进展和应用情况,简述了茶树生长信息获取方法、传感仪器和产业化应用的研究和发展趋势。选择合适的预处理和化学计量学方法能有效增加模型效果,减少冗余数据,为基于波谱技术便携式仪器的开发提供可能。基于波谱技术便携式仪器和在线检测仪器开发仍是今后实现该技术应用和推广的重点。首次介绍了波谱技术在茶叶生产加工领域的应用成果和研究进展,涵盖茶树生长、茶叶加工、茶叶和茶加工品品质安全等多方面内容,并论述波谱技术在茶叶产业应用存在问题和将来发展趋势。     

计算机在国产原子吸收光谱仪器中的应用

由于数字电子学和计算机技术的最新发展,计算机在AA(原子吸收)仪器方面的应用得到了迅速的发展,并取得了可喜的成绩。为AA仪器操作自动化、快速、高精度、高稳定性的数据处理、直观的屏幕显示等等提供方便。不带微机的AA仪器是把从光电倍增管出来的光强信号经过阻抗变换、对数变换、浓度直读等一系列复杂的线性电路实现吸光度和浓度直读的,如图1所示。仪器所具有的功能都是由复杂的电路,并经过反复地调试才得以实现。特别是曲线校直,往往给分析者带来很大的麻烦、使用起来很不方便。不管是国产的,还是进口的AA仪器都存在同样的问题。计算     

中国微束X射线荧光分析技术应用评介

简述了X射线荧光(XRF)分析与微束X射线荧光(MXRF)分析的技术特点、仪器构成、应用领域和工作范围。从准直的微束X射线荧光、整体X射线荧光与微束X射线荧光组合、波谱/能谱多功能组合和毛细管X光会聚透镜微束X射线荧光仪器四类仪器评介了中国微束X射线荧光仪器和分析技术的应用与发展。从分析功能定位和技术发展两方面,展望了微束X射线荧光技术的发展。提出将XRF分析中传统的微束原位(微区)XRF(MXRF)分析进一步区分为"微-纳区分析(μ/n-XRF)"和"微-毫区分析(μ/m-XRF)",如此区分该项技术及适用范围定位,对两者原位分析技术的发展都是有益的,特别也明确定位说明了整体/微区组合仪器的功能和适用范围发展与应用。作者强调:原位(微区)分析并非仅为单纯的分析工作,更重要的在于对被测样品特性的研究与结果解读!分析人员和专业科学家的密切合作,才能充分发挥原位微区分析技术的效能,充分解读展现分析结果的科学意义。     

辐射与发光 辐射测量与装置

TH765.2 2006031857全天候气象专用B波段紫外辐照计的研制=Developmentof special meteorological UV-B radiometer for all-cli mate[刊,中]/张保洲(北京师范大学天文系,北京市重点应用光学实验室.北京(100875)) ,王术军…∥计量学报.—2006 ,27(1) .—25-27 ,38研制了一种可全天候应用的B波段紫外辐照度及紫外指数测试系统,着重介绍其主要技术环节及性能,与国内现用的同类仪器进行了性能比对,分析了仪器试观测的结果。证明该仪器在带外杂光、余弦响应、温度控制等方面具有优良的性能,软件功能齐全,操作方便。图3表1参6(杨妹清)辐射与…     

泌尿系结石组分分析方法及其研究进展

对泌尿系结石组分进行准确的分析可为治疗尿石症和预防其复发提供重要的参考. 文章综述了现代仪器分析方法在草酸钙结石、磷酸盐结石、尿酸和尿酸盐结石及胱氨酸类结石等组分分析中的应用及其研究进展, 这些技术包括拉曼光谱、差热-热重(TGA/DTA)、核磁共振(NMR)、高效液相色谱(HPLC)和傅里叶红外光谱(FTIR)等.     

LT-1型离子探针质谱微分析仪

前 言 LT-1型离子探针质谱微分析仪(简称离子探针,本刊今年第2期封面刊登过此仪器外形及部份实验结果的照片)是一种利用离子光学原理制成的一种大型精密科学仪器.它主要应用于表面微区薄层分析,是半导体集成电路、固体物理、表面科学、材料科学、环境科学、地球和空间科学、生物学等研究工作中的一种重要分析工具. 近十年来,由于这些学科的发展,微区分析的仪器如电子探针、俄歇电子谱仪[1]等在一些性能方面已不能满足要求.离子探针的出现弥补了这些仪器的一些不足,与这些仪器相比,它的主要特点是: 1.灵敏度高:可以检测相对含量10～(-6)-10…     

《光散射学报》征稿简则

《光散射学报》是中国物理学会光散射专业委员会、四川省物理学会和四川大学联合主办的专业性学术刊物,宗旨是交流光散射(拉曼散射、布里渊散射、瑞利散射)、光物理、光化学、光生物等学科在理论、实验、实验技术和仪器方面的研究成果,以及它们在物理、化学、材料科学、生物学、地矿学、石油化工、医药学等方面的应用成果,为科学发展和技术进步提供讨论、交流场所。     

便携式X射线荧光光谱仪快速监测重金属土壤环境质量（英文）

便携式X射线荧光光谱仪(PXRF)作为一种新型快速测试手段具有突出的应用前景,但也存在检测范围和检测限的局限,为此本文研究PXRF仪器在快速监测土壤环境质量中Cr,Ni,Cu,Zn,Pb,Cd,As和Hg等8种重金属元素的适用性,筛选仪器可检测元素,评价检测结果准确度。具体方法是使用仪器测试重金属污染土壤样品,测试结果与电感耦合等离子体质谱分析方法(ICP-MS)测试值进行对比,评判检测结果精密度,建立PXRF仪器测试值与ICP-MS仪器测试值的线性回归关系。结果表明:(1)在监测重金属土壤环境质量时,PXRF仪器可用于检测土壤中Pb,Zn,Cr和Cu含量,但不适于检测Ni,Cd,As和Hg含量。(2)Pb和Zn测试值稍低于ICP-MS测试值,Cu偏高,而Cr过高;PXRF仪器测试值需要参照标准分析方法进行线性校正。研究结论为:便携式X射线荧光光谱仪适用于Pb,Zn,Cr和Cu等4种重金属的土壤环境质量监测,是一种简单快速、准确可靠的低成本土壤重金属分析手段。该研究的创新之处是合理规避PXRF仪器的缺点,将仪器应用于土壤环境质量监测,提高了测试结果应用价值。     

Assembly of full-spectrum k-distributions from a narrow-band database; effects of mixing gases, gases and nongray absorbing particles, and mixtures with nongray scatterers in nongray enclosures

Full-spectrum k-distributions provide great accuracy combined with outstanding numerical efficiency for the evaluation of radiative transfer in absorbing-emitting molecular gases, but they do have several shortcomings: (1) It is difficult to assemble k-distributions for gas mixtures from precalculated full-spectrum k-distributions of individual gas species (i.e., without calculating the mixture k-distribution directly from the HITRAN/HITEMP database), (2) it is impossible to assemble k-distributions for a gas mixed with nongray absorbing particles (such as soot) from gas-only full-spectrum k-distributions, and (3) like all global models, full-spectrum k-distributions cannot accommodate nongray scattering behavior and/or nongray wall reflectances. In the present paper we show how these restrictions can be relaxed by (1) assembling full-spectrum k-distributions for a gas mixture from a narrow-band k-distribution database created for individual gas species, (2) by assembling gas and nongray absorbing particle mixture full-spectrum k-distributions from the same narrow-band database, and finally (3) by showing how a group of part-spectrum k-distributions can be generated from the same database to accommodate nongray scattering and nongray walls.     

气相色谱法分析天然气成分

本文研究了气相色谱法测定天然气成分的分析方法,确定了计算方法及工作条件,并实测了城市燃气用天然气的常规成分,获得了满意的结果。     

气体峰值吸收系数随压强变化关系的理论分析

峰值吸收系数对于污染气体的定量分析以及分子参数的理论研究等都具有非常重要的意义。文章首先从理论上分析了气体的吸收系数α(ν) ,得出计算α(ν)的一般方法。其次通过分析甲烷 2ν3 带R3支吸收线 ,得出峰值吸收系数α(ν0 )随压强的变化关系 ,得到压强在 <0 0 3和 >2atm时 ,可分别用Gauss线型和Lorenz线型来计算峰值吸收系数 ,理论上得到很好的结果 ,并对结果进行了误差分析。最后讨论了单位长度峰值吸收κ(ν0 )随压强的变化关系 ,分析得出气体压强在 <0 1和 >1atm时可分别作为获得高分辨率和高灵敏光谱的气压条件     

Effects of gas saturation and sparging on sonochemical oxidation activity in open and closed systems,part II: NO2−/NO3− generation and a brief critical review

The sonochemical generation of NO₂⁻ and NO₃⁻ is considered to be one of the reasons for the low sonochemical oxidation activity in the presence of N₂ in the liquid phase. In this study, the generation characteristics of NO₂⁻ and NO₃⁻ were investigated using the same 28 kHz sonoreactor and the 12 gas conditions used in Part I of this study. Three gas modes, saturation/closed, saturation/open, and sparging/closed, were applied. N₂:Ar (25:75), N₂:Ar (50:50), and O₂:N₂ (25:75) in the saturation/closed mode generated the three highest values of NO₂⁻ and NO₃⁻. Ar and O₂ were vital for generating relatively large concentrations of NO₂⁻ and NO₃⁻. The absorption of N₂ from the air resulted in high generation of NO₂⁻ and NO₃⁻ for Ar 100 % and Ar/O₂ mixtures under the saturation/open mode. In addition, gas sparging enhanced the generation of NO₂⁻ and NO₃⁻ for N₂:Ar (25:75), O₂:N₂ (25:75), and N₂ significantly because of the change in the sonochemically active zone and the increase in the mixing intensity in the liquid phase, as discussed in Part I. The ratio of NO₃⁻ to NO₂⁻ was calculated using their final concentrations, and a ratio higher than 1 was obtained for the condition of Ar 100 %, Ar/O₂ mixtures, and O₂ 100 %, wherein a relatively high oxidation activity was detected. From a summary of the results and findings of previous studies, it was revealed that the observations of NO₂⁻ + NO₃⁻ could be more appropriate for investigating the NO₂⁻ and NO₃⁻ generation characteristics. In addition, H₂O₂/NO₂⁻/NO₃⁻ related activity rather than H₂O₂ activity was suggested to quantify the OH radical activity more appropriately in the presence of N₂.     

气相色谱法测定制鞋业废气中正己烷含量

应用溶剂解吸-气相色谱法测定制鞋业排放废气中的正己烷,采用活性碳管采集成型车间排气筒中的废气,用二硫化碳解吸,填充柱分离,经FID检测器检测。废气中与正己烷共存的苯、甲苯、二甲苯在该方法下不干扰测定。解吸率高,测定精度高,该法具有准确、快速、灵敏、简便的特点。     

靶丸内混合气体的质谱法测量技术

 叙述了四极质谱(QMS)的结构和气体分析质谱(GAM)的定量分析工作原理。四极质谱具有快速扫描响应，较高的响应灵敏度的特点，在经过标准气体校准后，加上独特的气体进样系统，可用于惯性约束聚变(ICF)靶丸内混合气体组分含量及总量的定量分析。同时，在经过坐标尺度放大等手段，可以对混合气体中质量数极为接近的氘(4.028 2)和氦(4.002 6)在高分辨模式下进行基线分离。用四极质谱对各种靶丸结构、不同混合气体种类的气体进行了定量组分分析，为ICF实验用靶提供了同批次实验数据。     

Effects of gas saturation and sparging on sonochemical oxidation activity in open and closed systems,Part I: H2O2 generation

Cavitational/sonochemical activity can be significantly enhanced or reduced depending on the gases dissolved in the liquid. Although many researchers have suggested the order of importance of dissolved gas conditions that affect the degree of sonoluminescence (SL), sonochemiluminescence (SCL), and compound degradation, the most suitable gas condition for sonochemical oxidation reactions is currently unknown. In this study (Part I), the effects of gas saturation and sparging on the generation of H₂O₂ were investigated in a 28-kHz sonoreactor system. Four gas modes, saturation/closed, saturation/open, sparging/closed, and sparging/open, were applied to Ar, O₂, N₂, and binary gas mixtures. The change in dissolved oxygen (DO) concentration during ultrasonic irradiation was measured and was used as an indicator of whether the gaseous exchange between liquid and air altered the gas content of the liquid. Considerable difference in the DO concentration was observed for the gas saturation/open mode, ranging from –11.5 mg/L (O₂ 100 %) to +4.3 mg/L (N₂ 100 %), while no significant difference was observed in the other gas modes. The change in the gas content significantly reduced the linearity for H₂O₂ generation, which followed pseudo-zero-order kinetics, and either positively or negatively affected H₂O₂ generation. Ar:O₂ (75:25) and Ar:O₂ (50:50) resulted in the highest and second-highest H₂O₂ generation for both gas saturation and sparging, respectively. In addition, gas sparging resulted in much higher H₂O₂ generation for all gas conditions compared to gas saturation; this was because of the significant change in the cavitational active zone and concentrated ultrasonic energy, which formed a bulb-shaped active zone, especially for the Ar/O₂ mixtures adjacent to the transducer at the bottom. The sparging flow rate and position also significantly affected H₂O₂ generation; the highest H₂O₂ generation was obtained when the sparger was placed at the bottom adjacent to the transducer, with a flow rate of 3 L/min.In Part II, the generation of nitrogen oxides, including nitrite (NO₂^–) and nitrate (NO₃^–), was investigated using the same ultrasonic system with three gas modes: saturation/open, saturation/closed, and sparging/closed.     

Gas discharges in very small gaps in relation to electrography

Gas discharges in very small electrode arrangements, with air gaps below 50 microns, as are often used in modern electrostatic recording, have been studied. In particular, the breakdown voltage as a function of the air gap, the charging mechanism for various recording media, the statistical variation of the time lag of the discharges as well as the temporal formation of the discharge have all been investigated. There is good agreement between experimental and theoretical results.     

光纤传感材料SnO2的气敏光反射特性研究

作者研究了二氧化锡的气敏光反射特性,测量了它在乙醇,氨,丙酮气体中的浓度与气敏反射光谱关系,发现它对氨气的气敏光谱波长灵敏范围最大,而且不同波长有不同的灵敏度。解释SnO₂气敏光反射机理。     

Effect of dissolved gases on sonochemical oxidation in a 20 kHz probe system: Continuous monitoring of dissolved oxygen concentration and sonochemical oxidation activity

Dissolved gases have a substantial influence on acoustic cavitation and sonochemical oxidation reactions. Little research on the changes in dissolved gases and the resultant changes in sonochemical oxidation has been reported, and most studies have focused only on the initial dissolved gas conditions. In this study, the dissolved oxygen (DO) concentration was measured continuously during ultrasonic irradiation using an optical sensor in different gas modes (saturation/open, saturation/closed, and sparging/closed modes). Simultaneously, the resulting changes in sonochemical oxidation were quantified using KI dosimetry. In the saturation/open mode using five gas conditions of Ar and O₂, the DO concentration decreased rapidly when O₂ was present because of active gas exchange with the atmosphere, and the DO concentration increased when 100% Ar was used. As a result, the order of the zero-order reaction constant for the first 10 min (k_0-10) decreased in the order Ar:O₂ (75:25) > 100% Ar ≈ Ar:O₂ (50:50) > Ar:O₂ (25:75) > 100% O₂, whereas that during the last 10 min (k_20-30) when the DO concentration was relatively stable, decreased in the order 100% Ar > Ar:O₂ (75:25) > Ar:O₂ (50:50) ≈ Ar:O₂ (20:75) > 100% O₂. In the saturation/closed mode, the DO concentration decreased to approximately 70–80% of the initial level because of ultrasonic degassing, and there was no influence of gases other than Ar and O₂. Consequently, k_0-10 and k_20-30 decreased in the order Ar:O₂ (75:25) > Ar:O₂ (50:50) > Ar:O₂ (25:75) > 100% Ar > 100% O₂. In the sparging/closed mode, the DO concentration was maintained at approximately 90% of the initial level because of the more active gas adsorption induced by gas sparging, and the values of k_0-10 and k_20-30 were almost the same as those in the saturation/closed mode. In the saturation/open and sparging/closed modes, the Ar:O₂ (75:25) condition was most favorable for enhancing sonochemical oxidation. However, a comparison of k_0-10 and k_20-30 indicated that there would be an optimal dissolved gas condition that was different from the initial gas condition. In addition, the mass-transfer and ultrasonic-degassing coefficients were calculated using changes in the DO concentration in the three modes.