HIGH-SPEED DIFFERENTIAL STOPPED-FLOW CALORIMETER

高速差示停流热量计

• 批准号: 3852932
• 负责人: C P MUDD
• 金额: --
• 依托单位: NATIONAL CENTER FOR RESEARCH RESOURCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3852932
• 关键词: biomedical equipment development; calorimetry; chemical reaction; fluid flow; stop flow technique; thermodynamics

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.

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， 和压力下降的热和光学时间过程中的化学 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度之间的恒定温度 和50摄氏度。 超快热敏电阻（1 ms）位于 检测室，以测量反应期间的温度上升。 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混合物的浓度。 反应 观察管现在由铸造聚氨酯制成， 涂上了一层1000埃厚的钽来防水 蒸气迁移 观察管在O形密封圈中“浮动”， 混合过程中的冲击载荷。 采用线性光学编码器测量 驱动注射器的位移。