HIGH-SPEED DIFFERENTIAL STOPPED-FLOW CALORIMETER

一种双通道、差动、高速、停流式量热计， 被构造来研究混合速度，流速， 化学物质的热和光学时间过程中的压力下降 反应. 该系统采用变速飞轮和电动 致动离合器以将足够的能量传递到四个驱动注射器 以在5毫秒或更短时间内混合200微升的试剂体积。 来自驱动注射器的入口管，以及混合器和 检测室，保持在25~ 50 ℃之间的恒温。 超快热敏电阻（1 ms）位于检测室中， 测量反应过程中的温升。 驱动凸轮轮廓 产生注射器的恒定加速度。 光学 透明的混合室允许对反应进行光学测量。 观察管现在由涂有 1000-_-厚的钽层，以防止水蒸气迁移。 的 观察管“浮动”在O形环密封，以减少冲击负荷， 混合 采用线性光学编码器测量位移， 驱动注射器

A dual-channel, differential, high-speed, stopped-flow calorimeter has been constructed to study the effects of mixing speeds, flow velocities, and pressure drops on the thermal and optical time course of chemical reactions. The system uses a variable-speed flywheel and an electrically actuated clutch to transfer sufficient energy to the four drive syringes to mix reagent volumes of 200 microliters in 5 milliseconds or less. The inlet tubes from the drive syringes, as well as the mixer and the detection chamber, are kept at constant temperature between 25~ and 50~C. An ultrafast thermistor (1 ms) is located in the detection chamber to measure the temperature rise during the reaction. The drive cam profile produces a constant acceleration of the syringes. An optically transparent mixing chamber allows optical measurement of the reaction. The observation tube is now made of cast urethane coated with a 1000-_-thick layer of tantalum to prevent water vapor migration. The observation tube "floats" in O-ring seals to reduce shock loads during mixing. A linear optical encoder is used to measure the displacement of the drive syringes.