Polymer crystallization dynamics,as reflected by differential scanning calorimetry. Part 1: On the calibration of the apparatus

In this paper a method for the calibration of the heat transfer coefficient between pan and furnace is given. This (second) calibration is necessary in addition to the usual calibration of the temperature scale. Indeed, with increasing cooling rates as required for kinetic measurements, the finite heat flow resistance between pan and furnace becomes evident anyway. We also propose to enlarge this resistance deliberately, in order to separate the time scales of the control system and of the exponential return of the heat flow curve to the base line, as occurring after completion of the phase transition. Only in this way can the heat transfer coefficient be determined with some accuracy. Another advantage of a lowered heat transfer coefficient will be treated in a third paper. It enables an approximate treatment of polymer crystallization kinetics.     

物像空间位姿表征模型及标定技术研究

从对单目视觉系统的空间定位技术着眼，本文研究了一种利用标准平面镜反射辅助三维空间测量的模型和方法。首先基于摄像机标定的基本原理，以条纹反射检测系统为初始结构，建立应用标准镜测量显示屏的空间位姿的物理模型，然后在对摄像机标定不确定度进行实验标定的基础上，进行了对条纹反射检测系统的三维空间位姿描述和测量。研究结果验证了本文技术方法模型有效、精度较高，扩大了单目视觉系统的测量范围，获得了更加紧凑的物像空间位姿测量系统结构。     

校正变换矩阵法及其在五种芳香化合物同时测定中的应用

将目标变换因子分析中的自由浮动思想引入多元校正中,提出了一种新的多组分同时校正法——校正变换矩阵法。将该法应用于紫外分光光度法同时测定五种芳香族化合物,结果令人满意。与目标因子分析法和卡尔曼滤波法比较,本法具有更好的校正准确度。     

An atomic electronegative distance vector and carbon-13 nuclear magnetic resonance chemical shifts of alcohols and alkanes

A novel atomic electronegative distance vector (AEDV) has been developed to express the chemical environment of various chemically equivalent carbon atoms in alcohols and alkanes. Combining AEDV and Y parameter, four five-parameter linear relationship equations of chemical shift for four types of carbon atoms are created by using multiple linear regression. Correlation coefficients are R = 0.9887, 0.9972, 0.9978 and 0.9968 and roots of mean square error are RMS = 0.906, 0. 821, 1.091 and 1.091 of four types of carbons, i.e., type 1, 2, 3, and 4 for primary, secondary, tertiary, and quaternary carbons, respectively. The stability and prediction capacity for external samples of four models have been tested by cross-validation.     

On the conductivity of an 0.01D aqueous potassium chloride solution

In a recent paper in this Journal, Saulnier and Barthel presented results for the electrolytic conductivity of 0.01 D potassium chloride solutions which they measured in a new type of conductance cell capable of absolute measurements at 0, 18 and 25°C. Their results disagreed by more than they expected from the results of Jones and Bradshaw at 18 and 25°C after they corrected the Jones and Bradshaw results to the absolute ohm and to the IPTS 1968. However their conversion was in error. The correct conversion is given and a recomparison is made with the Jones and Bradshaw results.     

The assessment of electronic balances for accuracy of mass measurements in the analytical laboratory

The accuracy of mass measurements when using electronic balances is considered within the frame of analytical assays in terms of the uncertainty budget according to the internal quality control routine, the calibration process, the balance specifications, and the weighing scenarios. Buoyancy corrections for both conventional and true mass are fully discussed. The procedure is illustrated with a worked example.     

在线式红外分光测油仪的校准

建立在线式红外分光测油仪的校准方法。在线式红外分光测油仪的校准主要包括绝缘电阻、示值误差、重复性、漂移和最小检出浓度等项目。通过分析实验数据,测量范围不大于10 mg/L时,示值误差不超过±0.8 mg/L;测量范围大于10 mg/L时,示值相对误差不超过±8%;重复性不大于2%;零点漂移不超过±0.5 mg/L,示值漂移不超过±5%;最小检出浓度不大于0.5 mg/L,仪器的计量性能正常。据此对影响仪器性能的各个参数进行全面评价,确认各项指标控制在合理范围内。该校准方法切实可行,可用于在线式红外分光测油仪的校准。     

Glyoxal measurement with a proton transfer reaction time of flight mass spectrometer (PTR‐TOF‐MS): characterization and calibration

We examine the potential for PTR‐TOF‐MS systems to quantitatively measure glyoxal in ambient air by characterizing the response of the instrument to a dilute glyoxal sample, calibrating the system as a function of humidity. The concentration of glyoxal in a sample air‐stream was measured with an UV absorption spectrometer in parallel to a PTR‐TOF‐MS. This calibration demonstrated that the PTR‐TOF‐MS has a relatively low sensitivity to glyoxal particularly at high humidity. Extensive fragmentation of glyoxal to formaldehyde was observed. This behaviour not only desensitizes PTR‐MS system to glyoxal; it may also pose a problem to the quantification of formaldehyde. © 2016 The Authors. Journal of Mass Spectrometry Published by John Wiley & Sons Ltd.