标准物质的应用

标准物质是具有准确的特性量值,高度均匀与良好稳定性的测量标准。是国民经济各个领域里的测量数据可比性与一致性起着重要作用的计量标准。钢铁标准物质,不仅是钢铁化学分析量值传递的基础,而且是校准仪器,评价测量方法和确定材料特性量值的物质。     

原子吸收分光光度计的期间核查方法及应用

文章阐述了原子吸收分光光度计期间核查的目的及方法,按仪器检定规程对仪器进行期间核查,以确保仪器校准状态的可信度。     

浅析信息系统中设备数据采集方法

随着企业信息化的进一步深入,计算机以及各种企业数据管理系统的应用领域也愈来愈广,其已经成为现代化企业管理不可或缺的工具。影响企业数据管理系统实施成功的因素很多,仪器数据的自动采集和处理就是其中重要的因素之一。本文就计量检测管理信息系统在检测企业的应用为例介绍仪器数据采集的方案和仪器连接数据库的方式以及各种方式的的优缺点和应用。重点介绍了利用虚拟仪器采集和从串口直接采集数据这两种方式。     

石煤钒矿中五氧化二钒容量法测定及量值溯源研究

通过标准物质量值溯源与校准、不同样品分解方法对比测定、倍比试验、标准加入与回收试验、不同分析方法结果比对等手段,开展了石煤中五氧化二钒容量法测定研究。结果表明:采用硫酸亚铁铵容量法测定石煤钒矿样品中的五氧化二钒,具有操作简便、结果准确和测定精密度高等优点,但要获得样品中准确的五氧化二钒质量百分数结果,必须熟练掌握容量法测定的技术关键。     

光谱分析数据采集与传输网络

介绍了基于ＷｉｎｄｏｗｓＮＴ网络和专用数据传输接口设备的光谱分析数据采集与传输网络,以及相应的软件和硬件设计方案;建立了一套临线和在线分析的数据采集、存储与传输的通用的新方法。解决了光谱仪串口数据格式的自动识别和工业环境下数据传输设备的抗干扰问题。专门设计的数据传输接口设备的传输距离可达３０００ｍ,端口数目可达３０个。采用星型网络拓扑结构,１０／１００ＢａｓｅＴＵＴＰ线缆连接,提供远程拨入和Ｉｎｔｅｒｎｅｔ连接,因此能够提供远程数据管理、远程系统维护以及基于局域网和Ｉｎｔｅｒｎｅｔ的二次开发和应用。结合工艺参数管理软件,不仅能够实现分析数据的现场显示,还能实现炼钢过程中合金化调整的加料计算和投料控制,从而实现冶炼过程的临界控制     

检定校准信息管理系统的功能及效果描述

计量检测是保障产品质量的一道关键工序,计量器具的量值准确、操作规范是计量可靠的基础.改变基于单机处理数据、依靠纸质流转传递信息的传统管理模式,开发出以检定/校准全过程的质量跟踪、实现公司测量设备全生命周期管理为核心的检定/校准实验室信息管理系统,提高包钢测量设备量传溯源准确性、可靠性,规范实验室人员、设备、资料档案等资源的综合管理,提升包钢计量管理水平.     

紫外可见分光光度计的测量结果不确定度分析

按《GB/T75481 2000检测和校准实验室能力的通用要求》的规定:各校准实验室或进行自校准的检测实验室,对所有的校准和各种校准类型都应具有和评定测量不确定度的陈述,故作者所在实验室也按其规定要求对新购的测试仪器进行了检测调试。该文以高碘酸钾氧化分光光度法测定钢铁及其合金中的锰量为例,介绍了UV 9100型紫外可见分光光度计测定钢铁中锰的测量不确定度,以及采用相对法求线性回归方程并用于检查前述测量不确定度的方法。结果显示UV 9100紫外分光光度计测量锰量的扩展不确定度为:u95=0.0379。     

石煤中五氧化二钒的磷钨钒酸光度法测定研究与应用

磷钨钒酸光度法是测定矿石中五氧化二钒含量的方法之一,但将该法应用到石煤钒矿标准物质研制的定值中,还存在很多不足;通过采用量值溯源与校验、测定方法的改进和基体影响的研究等手段,对石煤中五氧化二钒磷钨钒酸光度法测定进行了研究,结果表明,采用基准五氧化二钒配制标准溶液,能提高测定结果的准确度,同时,对基体影响的研究弄清了该法的稳定性、准确性和扩展测定范围的方法。最后将研究方法应用到石煤钒矿标准物质研制的定值,达到了量值溯源的目的,4个候选物10次平行测定相对标准偏差仅2.86%~4.87%。     

MOXA串口设备联网服务器在柳钢能源管理系统的应用

正柳钢目前在用的能源管理系统,对公司的一、二级能源计量及重点三级能源计量进行集中数据采集和数据管理。系统建设时,在中心机房部署了数台数采服务器,通过光纤以太网连接到现场测量仪表。但是,很多测量点(如大部分一、二级的水表、电表计量点)所用的测量仪表没有以太网通讯接口,而只提供了RS485串口通讯接口,无法直接通过以太网与数采服务器进行通讯。基于这种情况,选择使用Moxa科技有限公司的NPort 5X50串口设备联网服务器来进行这些现场测量仪表的数据采集。本文进行总     

力控组态软件在柳钢能源网络中的数采应用

介绍了柳钢能源网络数据采集系统优化更新改造——采用更为先进与专业的力控Force Control组态软件,对不同协议的仪表进行组态以及建立画面并连接数据库,从而实现现场仪表的快速准确的数据采集及对生产系统的能源网络的全过程控制管理。     

Improving calibration accuracy in gel dosimetry

A new method of calibrating gel dosimeters (applicable to both Fricke and polyacrylamide gels) is presented which has intrinsically higher accuracy than current methods, and requires less gel. Two test-tubes of gel (inner diameter 2.5 cm, length 20 cm) are irradiated separately with a 10 x 10 cm2 field end-on in a water bath, such that the characteristic depth-dose curve is recorded in the gel. The calibration is then determined by fitting the depth-dose measured in water, against the measured change in relaxivity with depth in the gel. Increased accuracy is achieved in this simple depth-dose geometry by averaging the relaxivity at each depth. A large number of calibration data points, each with relatively high accuracy, are obtained. Calibration data over the full range of dose (1.6-10 Gy) is obtained by irradiating one test-tube to 10 Gy at dose maximum (Dmax), and the other to 4.5 Gy at Dmax. The new calibration method is compared with a 'standard method' where five identical test-tubes of gel were irradiated to different known doses between 2 and 10 Gy. The percentage uncertainties in the slope and intercept of the calibration fit are found to be lower with the new method by a factor of about 4 and 10 respectively, when compared with the standard method and with published values. The gel was found to respond linearly within the error bars up to doses of 7 Gy, with a slope of 0.233 +/- 0.001 s(-1) Gy(-1) and an intercept of 1.106 +/- 0.005 Gy. For higher doses, nonlinear behaviour was observed.     

Validation of a hand-held lactate device in determination of blood lactate in critically injured patients

OBJECTIVES: Admission blood lactate is an accurate predictor of injury severity and mortality in trauma patients. The purpose of this study was to evaluate a portable lactate analyzer in a clinical setting by patient care staff. DESIGN: A prospective, single-operator control solution and patient sample study, using two test devices and a reference device. SETTING: An urban Level I trauma center. PATIENTS: A convenience sample of 47 trauma patients. INTERVENTIONS: Intra-assay precision was demonstrated by performance of consecutive analyses of two lactate control solutions (high and low lactate control concentrations) by medical students and physicians. Split sample, simultaneous testing of the portable lactate analyzer was then performed on 66 whole blood specimens from a convenience sample of 47 trauma patients admitted to an urban Level 1 trauma center over 4 mos. Samples were tested simultaneously tested on two portable lactate analyzers and a reference instrument. MEASUREMENTS AND MAIN RESULTS: Acceptable intra-assay precision was achieved. Regression analysis for two test instruments demonstrated a slope of 0.920, an intercept of 0.323, an r2 of .982, and an SEM of 0.496. Regression analysis for test instrument "A" vs. the reference instrument showed a slope of 0.861, an intercept of 0.209, an r2 of .977, and an SEM of 0.598. Regression analysis for test instrument "B" vs. the reference instrument demonstrated a slope of 0.929, an intercept of -0.095, an r2 of .983, and an SEM of 0.506. CONCLUSIONS: Good correlation with a low SEM was obtained over a wide range of clinically relevant lactate values. Use of point of care lactate analysis will decrease analytic time, making an important diagnostic parameter immediately available in the critical care setting.     

Oramucosal delivery of LHRH: pharmacokinetic studies of controlled and enhanced transmucosal permeation

A method base on the two-compartment model was developed to measure quantitative cerebral blood flow (CBF) and partition coefficient (lambda) of IMP from dynamic SPECT and single arterial blood sampling. In this method, the linear differential equation of two-compartment model, Yokoi proposed, was employed and quantitative CBF and lambda values were measured with the standard input function calibrated by single arterial sampling. The input function was derived from the standard input function scaled by a factor determined by the single arterial blood sample. This new technique was applied to 5 normal volunteers (Ages ranged from 25 to 29 yr., average 26 yr.). The optimal time to calibrate the standard input function in the individual study and optimal the period of the upper limit time to which input function is integrated from IMP administration for analysis of the equation were determined to minimize the difference between integration of the calibrated standard input function and of the individual input function. Minimization of the difference yields an optimal calibration time (4 to 10 min after IMP administration) and the period of the upper limit time (8 to 60 min after acquisition start). Comparison of CBF and lambda values obtained by the graphical method using the calibrated standard data and individual input function were performed. It should be noted that CBF values were in good agreement between the two methods, respectively (r = 0.92, P<0.01; r = 0.72, p = 0.01). This method is easy to estimate CBF and lambda by only single arterial blood sampling and IMP dynamic SPECT, and useful for routine studies.     

Does working at your marriage help? Couple relationship self-regulation and satisfaction in the first 4 years of marriage.

Relationship self-regulation (SR) is how much partners work at their couple relationship, and it has been hypothesized to predict relationship satisfaction. To test this hypothesis, the authors assessed 191 newlywed couples on SR and relationship satisfaction annually for 5 years. They conducted a multilevel analysis predicting satisfaction with SR as a time-varying covariate. The intercept and slope of relationship satisfaction varied across participants, and the slope showed an average slight decline for both men and women. There was mixed support for the primary hypothesis. SR cross-sectionally and prospectively predicted the intercept, but it did not predict the slope, of relationship satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

碳硫分析仪长期稳定性测量方法研究

碳硫分析仪一般使用标准样品绘制校准曲线后直接测定未知样品中碳、硫元素含量,通过标准样品或控制样品的实时核查实现对仪器及校准曲线的长时间监控使用,因此,测量出仪器的长期稳定性时间上限(T_MAX)十分必要。长期稳定性测量即是监控测量结果的准确度,包括精密度和正确度。针对本实验室内的碳硫分析仪设计长期稳定性试验,利用相关标准中的重复性及实验室内再现性精密度数据以及χ²统计量,对测量数据进行各时段内精密度、各时段内正确度、时段内重复性、时段间总精密度以及总均值正确度的检验,给出了碳硫分析仪的长期稳定性时间上限7h。在此时间内,仪器无需任何校正,节省了时间和成本。     

Comparison of two methods of therapy level calibration at 60Co gamma beams

The accuracy and traceability of the calibration of radiotherapy dosimeters is of great concern to those involved in the delivery of radiotherapy. It has been proposed that calibration should be carried out directly in terms of absorbed dose to water, instead of using the conventional and widely applied quantity of air kerma. In this study, the faithfulness in disseminating standards of both air kerma and absorbed dose to water were evaluated, through comparison of both types of calibration for three types of commonly used radiotherapy dosimeters at 60Co gamma beams at a few secondary and primary standard dosimetry laboratories (SSDLs and PSDLs). A supplementary aim was to demonstrate the impact which the change in the method of calibration would have on clinical dose measurements at the reference point. Within the estimated uncertainties, both the air kerma and absorbed dose to water calibration factors obtained at different laboratories were regarded as consistent. As might be expected, between the SSDLs traceable to the same PSDL the observed differences were smaller (less than 0.5%) than between PSDLs or SSDLs traceable to different PSDLs (up to 1.5%). This can mainly be attributed to the reported differences between the primary standards. The calibration factors obtained by the two methods differed by up to about 1.5% depending on the primary standards involved and on the parameters of calculation used for 60Co gamma radiation. It is concluded that this discrepancy should be settled before the new method of calibration at 60Co gamma beams in terms of absorbed dose to water is taken into routine use.     

Risk factors for male breast cancer (United States)

The significance of intersections in age-specific mortality rate distributions could be attributed to a fundamental statistical relationship between estimates of slope and intercept. A strong negative correlation between estimates of slope and intercept is often observed in simple linear regression problems. The net result is that the family of lines generated by repetitive estimates of slope and intercept in a static experimental situation will tend to intersect at a common point. This statistical relationship between slope and intercept, however, should be random with respect to the time-ordered sequence of slope and intercept estimates. Annual paired slope and intercept estimates derived using the method of longitudinal Gompertzian analysis of age-specific mortality rates for men and women in the United States from 1900 to 1988 were analyzed to determine if they varied randomly. The probability that the observed sequence in these annual paired slope-intercept estimates was random is less than 10(-50) for both men and women. This finding essentially excludes the possibility that intersections in age-specific mortality rate distributions reflect a fundamental statistical relationship between slope and intercept and further suggests biological relevance for the method of longitudinal Gompertzian analysis.     

A new analogue scale for assessing children's pain: an initial validation study

A new instrument was designed to provide a practical clinical measure for assessing children's pain intensity and pain affect. The pocket size measure includes a Coloured Analogue Scale (CAS) to assess intensity and a facial affective scale to assess the aversive component of pain. Both scales have numerical ratings on the back, so that the person administering it can quickly note the numbers that represent a child's pain. This study was conducted to determine the validity of the new instrument by evaluating the psychophysical properties of the intensity scale and by evaluating the discriminant validity of the intensity and affective scales. Since visual analogue scales (VAS) are valid and reliable measures for assessing children's pain, children's ability to use the new analog scale was compared with their performance on a VAS. Children's ability to rate pain affect using an affective scale, in which the 9 faces on a Facial Affective Scale (FAS) are presented in an ordered sequence from least to most distressed, was compared to their performance on the original FAS, in which the same faces were presented in a random order. Using a parallel groups design, 104 children (5-16 years; 60 female, 44 male; 51 healthy and 53 with recurrent headaches) were randomized into two groups: CAS or VAS. Children used the assigned scale to complete a calibration task, in which they rated the sizes of 7 circles varying in area (491, 804, 1385, 2923, 3848, 5675 and 7854 mm2). The psychophysical function relating perceived circle size to actual physical size was determined for the CAS and VAS. Children's CAS and VAS responses on the calibration task yielded similar mathematical relationships: psi cas = 0.035I0.87, psi vas = 0.027I0.89, where psi = perceived magnitude and I = stimulus intensity. The R2 values were 0.921 and 0.922 for the CAS and VAS groups, respectively. Analyses of covariance revealed no significant differences in the characteristics of these relationships, i.e., R2, slope, or y intercept, by scale type. Children used the same scale to complete the Children's Pain Inventory (CPI), in which they rated the intensity and affect of 16 painful events (varying in nature and extent of tissue damage). Children's CAS and VAS responses on the CPI were similar. Analyses of covariance indicated that there were no differences in either intensity or affective ratings by scale type. However, the mean number of painful events experienced by children increased significantly with age (P = 0.0001). Intensity ratings decreased significantly with age (P = 0.002), but affective ratings did not vary with age. The new instrument has equivalent psychometric properties to a 165 mm VAS. However, the CAS was rated as easier to administer and score than the VAS, so it may be more practical for routine clinical use. Since the CAS has fulfilled the first two criteria for a pain measure (psychophysical properties and discriminant validity), it is ethical to proceed with the formal definitive test for construct validity, in which children from various clinical populations use the CAS scale to assess their own pain.     

Memory for serial order: A network model of the phonological loop and its timing.

A connectionist model of human short-term memory is presented that extends the "phonological loop" (A. D. Baddeley, see record 1986-98526-000) to encompass serial order and learning. Psychological and neuropsychological data motivate separate layers of lexical, timing, and input and output phonemic information. Connection weights between layers show Hebbian learning and decay over short and long time scales. At recall, the timing signal is rerun, phonemic information feeds back from output to input, and lexical nodes compete to be selected. The selected node then receives decaying inhibition. The model provides an explanatory mechanism for the phonological loop and for the effects of serial position, presentation modality, lexicality, grouping, and Hebb repetition. It makes new psychological and neuropsychological predictions and is a starting point for understanding the role of the phonological loop in vocabulary acquisition and for interpreting data from functional neuroimaging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)