陳揚(yáng)
摘 ?要:示差掃描熱量計是在程序控制溫度下,測量試樣與參比物之間的加熱功率差或溫差的儀器。根據(jù)儀器測量原理的不同,可分為功率補(bǔ)償式示差掃描熱量計和熱流式示差掃描熱量計。示差掃描熱量計是一種多功能的量熱儀器,可測定物質(zhì)的熔融熱、相變熱、結(jié)晶熱等,廣泛用于化工、紡織、藥物、高分子等領(lǐng)域,也適用于新材料熱物性和化學(xué)性質(zhì)的測定。示差掃描熱量計測量的溫度和熱量的準(zhǔn)確與否,直接影響試樣的檢測結(jié)果。文章依據(jù)JJG 936-2012《示差掃描熱量計》檢定規(guī)程,對示差掃描熱量計測量結(jié)果進(jìn)行不確定度分析評定。
關(guān)鍵詞:示差掃描熱量計;標(biāo)準(zhǔn)物質(zhì);不確定度評定
中圖分類號:TH81 ? ? ? ? 文獻(xiàn)標(biāo)志碼:A ? ? ? ? 文章編號:2095-2945(2019)35-0016-02
Abstract: The differential scanning calorimeter is an instrument for measuring the heating power difference or temperature difference between the sample and the reference under the temperature controlled by the program. According to the different measuring principle of the instrument, it can be divided into power compensation differential scanning calorimeter and heat flow differential scanning calorimeter. Differential scanning calorimeter is a multi-functional calorimetric instrument, which can measure the melting heat, phase change heat, crystallization heat and so on. It is widely used in the fields of chemical industry, textile, medicine, polymer and so on. It is also suitable for the determination of thermophysical and chemical properties of new materials. Whether the temperature and heat measured by the differential scanning calorimeter is accurate or not directly affects the test results of the sample. According to the verification regulation of JJG 936-2012 "Differential Scanning Calorimeter", this paper analyzes and evaluates the uncertainty of the measurement results of differential scanning calorimeter.
Keywords: differential scanning calorimeter; reference material; uncertainty evaluation
1 溫度示值誤差測量結(jié)果的不確定度評定
1.1 測量過程簡述
1.1.1 測量依據(jù):JJG 936-2012《示差掃描熱量計檢定規(guī)程》
1.1.2 測量環(huán)境條件:溫度(15~30)℃,相對濕度不大于85%
1.1.3 測量標(biāo)準(zhǔn):熱分析標(biāo)準(zhǔn)物質(zhì)銦(In)、錫(Sn)、鉛(Pb)、鋅(Zn)、硝酸鉀(KNO3)、二氧化硅(SiO2),不確定度U=(0.06~0.94)℃(k=2)
1.1.4 被測對象:示差掃描熱量計。
1.1.5 測量方法:在規(guī)定的條件下,用In進(jìn)行測量,測量2次,2次的算術(shù)平均值與標(biāo)準(zhǔn)值之差值為溫度示值誤差。
1.2 數(shù)學(xué)模型
1.2.1 數(shù)學(xué)模型
3 結(jié)束語
用示差掃描熱量計檢定裝置檢定/校準(zhǔn)示差掃描熱量計,溫度誤差的不確定度為U=(0.2~1.0)℃(k=2),熱量誤差的不確定度為U=(0.20~1.4)J/g(k=2)。
參考文獻(xiàn):
[1]JJG 936-2012.示差掃描熱量計檢定規(guī)程[S].
[2]JJF1001-2018.通用計量術(shù)語及定義[S].
[3]JJF1059.1-2012.測量不確定度評定與表示[S].
[4]常穎,劉文敬,王文,等.示差掃描熱量計溫度示值誤差與熱量示值誤差的不確定度分析[J].工業(yè)計量,2016(S1):57-58.