Netsu Sokutei, 32 (2), p. 77, (2005)



Development and Applications of a nW-stabilized DSC

熱流束型DSCにおいて,温度センサーに半導体熱電素子モジュールの採用,±1 mK以内の断熱制御,±0.1 mK以内の昇降温制御,試料セル近傍の温度変動を±0.1 mKのオーダーとするための温度減衰方法の採用,計測系へのノイズ,迷起電力が±1 nVのオーダーとする工夫により,ベースラインの安定性±3 nW程度,装置の応答速度2 s程度で,装置の温度分解能0.1 mK程度のDSCを製作した。このDSCを用いて,mgのオーダーの試料量のパルミチン酸とドトリアコンタンの融解挙動を測定した。試料量が減少するにつれて融点の低下が観測されたが,これは試料分子と試料容器との相互作用によるものと理解される。また,ドコサンの測定では,液体上単分子層の存在の検出や新しい多段階相転移や相転移の微細構造の検出に成功した。
A high sensitivity and high resolution DSC working between 220 and 400 K with a baseline stability of ±3 nW, with a low noise of nV order, with a quick response time of 2 s and with a temperature resolution of 0.1 mK, capable of measuring in the both directions of heating and cooling has been designed and constructed. The stability of the baseline was achieved by the use of a high sensitive temperature sensor, a precise temperature control of ±0.1 mK, an adiabatic control, the damping devices to decrease the temperature fluctuation at the sample cell and the devices to decrease noises on the lead wires. Very fine structures of phase transitions were observed at a cooling rate of 5 mKs-1 in the measurement of C22H46 by application of the nW-stabilized DSC. The measurement of the melting of C15H31COOH and C32H66 employing very small samples of mg order was carried out as well and the results demonstrated the high sensibility of the nW-stabilized DSC.