HIGH-SPEED DIFFERENTIAL STOPPED-FLOW CALORIMETER

高速差示停流热量计

• 批准号: 3789400
• 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/3789400
• 关键词: biomedical equipment development; calorimetry; chemical reaction; fluid flow; stop flow technique; thermodynamics; thermography

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.

双通道，差分，高速，止流量热计有