HIGH-SPEED DIFFERENTIAL STOPPED-FLOW CALORIMETER

一种双通道、差动、高速、停流量热计 是用来研究混合速度、流动速度、 在化学物质的热和光学时间过程中的压降 反应。该系统使用了一个变速飞轮和一个电动马达 驱动离合器，将足够的能量传递给四个驱动注射器 在5毫秒或更短的时间内混合200微升的试剂。这个 从驱动注射器以及混合器和 检测室，保持在25度之间的恒温 和50摄氏度，一个超快热敏电阻(1毫秒)位于 检测室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光学测量 反应。观察管现在是由铸造的氨基甲酸酯制成的， 被涂上1000埃厚的钽层以防止水分 水蒸气迁移。观察管在O形圈密封中“漂浮”以减少 混合过程中的冲击载荷。使用线性光学编码器来测量 驱动注射器的移位。

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 degrees and 50 degrees 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 that has been coated with a 1000-Angstrom-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.