悬浮液氢化物发生—原子荧光光谱法测定地质样品中痕量铋？…

提出一种固体粉末悬浮液中氢化物发生－原子荧光光谱法测定地质样品中痕量铋的新方法，经ＧＳＤ（国家水系沉积物标准样）系列标准分析验证，结果可靠。     

ICP-AES法测定铁-镍-钴基高温合金中的镧、钇

本文研究了铁－镍－钴基合金中Ｌａ,Ｙ元素的电感耦合等离子体发射光谱的测定,并研究了基体和共存元素对测定的影响。通过精密度和准确度试验,表明方法准确,可靠,并取得了满意的结果。     

Three dimensional analytical determination of the track parameters

An analytical three dimensional method was applied in determination of the track parameters. The general three dimensional equation of the track wall was derived. This equation was used for the determination of the track parameters for constant and variable V_t. The formulas for constant V_t are equal to the previously given expressions obtained in another independent manner. The general equations of contour line, width and length of the track opening (for V_t≠constant) were derived.     

Understanding the source of signal fluctuations in laser-induced breakdown spectroscopy analytical applications

A recent paper [¹] by the group of Prof. Zhe Wang, Beijing, China reveals the physical mechanism responsible of the signal fluctuations in laser-induced breakdown spectroscopy analysis.     

ICP-AES测定地质样品中的La、Ce和Y

用碱熔地质样品,三乙醇胺掩蔽铁、铝,乙二醇双(2-氨基乙基醚)四乙酸(EGTA)络合钙、钡,经过滤用HCl-H2O2溶解沉淀,用水定容后以ICP-AES测定La、Ce、Y,此方法简便,准确.     

正交信号校正用于偏最小二乘建模过拟合现象的研究

通过用近红外光谱和PLS建立测定二元、三元调合食用油中花生油含最模型以及二甲亚砜水溶液浓度模型,使用交互验证统计参数,包括决定系数RC,标准偏差SEC,预测值和实际值线性拟合方程的斜率a和截距b,和外部验证统计参数,包括决定系数RV,标准偏差SEP,预测值和实际值线性拟合方程的斜率a和截距b,评价建模效果,比较了分别使用原始光谱和正交信号校正(OSC)处理光谱的PLS建模结果.研究结果表明:OSC校正可明显改善近红外光谱与被测物质浓度的线性相关性.虽然OSC预处理可以改善PLS模型的交互验证结果,似是外部验证结果变差,即正交信号校正用于PLS建模将导致过拟合现象.通过分析算法原理,认为OSC与PLS1对光谱中与性质无关的信息作了重复剔除,误删除了部分有效信息,导致过拟合效应.     

Model for the analytical signal in atomic absorption spectrometry with electrothermal atomization

A method for verification of analytical measurements in electrothermal atomic absorption spectrometry using a phenomenological model for physicochemical atomization processes is discussed. The influence of the sample matrix on basic kinetic parameters of atomization such as the analyte free-atom formation energy and the atomization rate constant has been shown. The similarity of atomization kinetic parameters obtained by calibrating the spectrometer to those for samples under study can be used as a verification criterion for analysis. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 295–298, May–June, 2008.     

Betterment in EDXRF analytical results for compositional characterization of mixed uranium thorium oxide samples with bead specimens compared with pressed pellet specimens

A comparative study on the energy dispersive X‐ray fluorescence analytical results of uranium determinations, in uranium and uranium–thorium mixed oxides, using specimens in the form of fused beads and pressed pellets, has been made. It was observed that in case of fusion bead specimens, the intensity of the analyte lines was approximately 1.6 times of that observed in pellet specimens under identical instrumental conditions. In case of uranium oxide samples, the analytical results with bead specimens were slightly better compared with the pellet specimens. However, in case of the uranium–thorium oxide mixtures, the average precision obtained with bead specimen was significantly better (1%, 1 s) in comparison with that achieved using pellet specimens (7%, 1 s). This difference may be due to the hardness of thorium oxide compared with uranium oxide, which affects the homogeneity of the pellet specimens prepared. In fusion bead method of sample preparation, even highly refractory material like ThO₂ forms uniform glass beads. Addition of internal standard further improves the analytical results, with reduction in the percent deviation of energy dispersive X‐ray fluorescence results from the expected values to 3% from 7% compared with that obtained using without internal standard. The fusion bead method of sample preparation will be very useful for characterization of sintered (U,Th)O₂ pellets, which are highly refractory and difficult to dissolve. Copyright © 2016 John Wiley & Sons, Ltd.     

地质样品铷锶钇锆元素偏振能量色散X射线荧光光谱分析结果不确定度的评估

建立了一种以相对误差的标准偏差统计不确定度的评估方法.运用镶边压片技术制备样片,用Spectm X-Lab 2000型偏振能量色散X射线荧光光谱(P-EDXRF)仪器分析硅酸盐基体的76个国家一级标准物质和89个地质行业多目标考核样品,研究表明165个样品Rb,Sr,Y和Zr元素测量结果的相对误差符合正态分布(置信度为95%).以此为依据,分段统计相对误差的标准偏差作为对应浓度段被测量结果的总相对不确定度,扩展因子为2.分段统计精密度引起的相对不确定度,剥离出准确度引起的相对不确定度.不同元素准确度引起的相对不确定度在总不确定度中所占比例不同.通过"实验室测量审核结果公式"和"标准值及其扩展不确定度与测试修正值及其扩展不确定度的比较"丽种方式,验证了总相对不确定度统计方式具有合理性.     

Preheat-induced signal enhancement in the infrared stimulated luminescence of young and bleached sediment samples

Natural and laboratory bleached surface and young samples of potassium feldspar sand separates and polymineral silt had their infrared stimulated luminescence (IRSL) signal measured before and after preheating at 220°C for 10 min or 160°C for 16 h. For both preheats, the laboratory bleached sand samples underwent a signal enhancement which was stable with laboratory storage. The youngest samples also showed natural signal enhancement. The silt sample showed no recuperation of bleached signal on preheating, but some in the natural signal. A range of filtered bleaches was applied to one surface sand sample. Signal levels before and after preheating were reduced by filtering out the UV from the bleaching spectrum. The unfiltered bleach, however, most closely reproduced the behaviour of the natural sample.     

Spectrophotometric determination of sparfloxacin in pharmaceutical formulations and urine samples

A simple and sensitive spectrophotometric method has been developed for the determination of sparfloxacin in bulk and pharmaceutical formulations, and in artificial urine. Sparfloxacin was oxidized into a red colored product using ammonium monovanadate in acidic media. The proposed method was successfully applied to the determination of sparfloxacin in different pharmaceutical formulations (tablets) and in a spiked urine sample. The influence of commonly used excipients on the determination of sparfloxacin was studied. Percentage recoveries in the range of 98.0 ± 0.14 % to 100.0 ± 0.20 % were obtained. The observed data have been evaluated statistically which showed high accuracy and precision.     

Combustion parameters identification and correction in diesel engine via vibration acceleration signal

Using closed loop control of the internal combustion engine is beneficial to reducing emission and fuel consumption. Accurate combustion parameters are the foundation of effective closed loop control. Some combustion parameters, including the start of combustion, the location of maximum pressure rise rate and the location of peak pressure can be identified from the vibration signals. Empirical Mode Decomposition (EMD) method is introduced to reconstruct the vibration acceleration signal, from which the combustion parameters are identified. However, there are angle deviations between the combustion parameters extracted from the reconstructed vibration acceleration signal and those from the cylinder pressure. Algorithms to correct the angle deviations are introduced. A system deviation value is used to correct the extracted start of combustion with an error bound being within 0.6 °CA. Two algorithms are proposed to correct the deviation between the predicted location of maximum pressure rise rate and that from the cylinder pressure. Test results show that the two algorithms are able to correct the deviation within 0.3 °CA error bound. The location of peak pressure can be predicted with the knee point following the peak value in the reconstructed vibration acceleration signal. The predicted result is then corrected using a linear regression of the location of peak pressure versus the knee point within 0.5 °CA error bound. A real-time monitoring framework is utilized for calculating the combustion parameter prediction.     

Oscillation and extinction thresholds of the clarinet: comparison of analytical results and experiments

In the context of a simplified model of the clarinet in which the losses are assumed to be frequency independent the analytic expressions of the various thresholds have been calculated in a previous paper [Dalmont et al., J. Acoust. Soc. Am. 118, 32.94-3305 (2005)]. The present work is a quantitative comparison between "theoretical" values of the thresholds and their experimental values measured by using an artificial mouth. It is shown that the "Raman" model, providing that nonlinear losses are taken into account, is reliable and able to predict the values of thresholds.     

FEL gain in the pulsed regime: a comparison between numerical and analytical results

Summary In this paper we present simple and general formulae for the FEL gain in the pulsed regime including both the longitudinal mode coupling and the lethargy effect. Such relations, obtained from a numerical integration of the pulse propagation equations, are then compared to similar expressions obtained analitycally in the limiting case of the long bunch approximation and the agreement is shown to be excellent.

---

Riassunto In questo lavoro vengono derivate formule semplici e generali relative al guadagno FEL in regime impulsato. Tali formule tengono conto dell'accoppiamento tra i modi longitudinali e dell'effetto di letargia. Le relazioni di cui sopra sono ottenute nell'ambito di una trattazione numerica delle equazioni di propagazione degli impulsi e sono poi comparate ad analoghe espressioni ottenute per via analitica nel caso limite di pacchetto di elettroni lungo. Si dimostra come l'accordo sia particolarmente buono.

---

Резюме В зтой статье мы приводим простые и общие формулы для усиления для лазера на свободных злектронах в импульсном режиме, учитывая связь продольных мод и зффект летаргии. Зти соотношения, полченные с помощью численного интегрирования уравнений распространения импульса, затем сравниваются с аналогичными выражениями, полученными аналитически в предельном случае приближения длинного сгустка, и получается хорошее согласие.

     

直接正交信号校正算法在烷烃类多组分气体定量分析中的应用

针对烷烃类多组分混合气体中红外光谱存在的基线漂移问题,提出一种直接正交信号校正算法用于光谱数据预处理。实验中采用傅里叶变换红外光谱仪采集了936组混合气体样本的光谱数据,混合气体主要由不同浓度范围的七种组分气体组成。将直接正交信号校正算法与导数算法进行了对比分析,采用偏最小二乘回归方法建立了各组分气体定量分析模型,并对模型参数(主元个数、导数步长及正交分量的个数)进行了遍历优化选取最优分析模型。结果表明直接正交信号校正算法对于中红外光谱基线校正效果最好,直接正交信号校正算法用于烷烃类混合气体中红外光谱基线校正可行,效果良好,具有一定的实用和研究价值。     

密封Cf源的成分测定和中子发射率修正

当密封Cf源寿命超过20年后,其他同位素和子体核素尤其Cf-250和Cm-248的贡献不断增大,使得Cf源中子发射率不能简单按照Cf-252半衰期进行估算。基于Cf源中同位素及其子体核素的衰变和自发裂变规律,提出了一种测定密封Cf源中Cf-252和Cf-250成分的方法,达到快速估算寿命超过20年的Cf源中子发射率的目的。采用长计数器相对测量得到一个使用近30年Cf源在某一时刻的中子发射率,确定了该源初始时刻Cf-252和Cf-250原子核数分别为4.4521016和7.7461015,据此给出了Cf源的中子发射率随时间的变化关系。同时在另外两个时刻的推算结果与长计数器测量结果符合得非常好,相对偏差小于0.3%,进一步验证了该方法的可靠性。此外还对Cf-252,Cf-250和Cm-248对中子发射率的贡献与中子源寿命的关系进行了分析,结果表明当Cf源寿命达到30年时,Cf-252对总中子发射率的贡献已经降至67.65%,而Cf-250和Cm-248的贡献已经达到29.32%和2.94%。     

Statistical properties of excited nuclei and the determination of the ground-state shell correction energies

It is shown that the ground-state shell correction energies of nuclei can be obtained from a study of the high temperature behaviour of their thermodynamic properties without recourse to Strutinsky's smearing procedure.