Mudd C
C & E Engineering Services, Charlottesville, VA 22911, USA.
J Biochem Biophys Methods. 1999 Feb 25;39(1-2):7-38. doi: 10.1016/s0165-022x(98)00045-1.
A technique is presented which allows the development of extremely complex (> 5000 components) RC models of calorimeters and provides simulation under a wide variety of inputs. A commercially available circuit simulation program (SPICE) is used to 'build' RC models of relaxation and scanning calorimeter designs used to measure heat capacity. The instrument models are constructed using subcircuits to represent small elements of the materials used in the designs. Only simple linear equations are needed to evaluate the RC values in the subcircuit. The subcircuits also use voltage controlled switches to simulate phase transitions where lambda, C, and delta h can change value instantaneously at predetermined temperatures. The resulting simulations of the two designs provide an ability to predict instrument sensitivity to lambda and C independently. Simulated outputs agree with measured outputs within 10%. Model simulations show serious errors in the heat capacity determinations from both designs during phase transitions. Interactions between lambda, C, and delta h are shown for both designs. The technique provides a means to construct, evaluate, and optimize a calorimeter design completely in software.
本文介绍了一种技术，该技术可用于开发极其复杂（>5000个组件）的量热计RC模型，并能在多种输入条件下进行模拟。使用一个商用电路模拟程序（SPICE）来“构建”用于测量热容量的弛豫型和扫描型量热计设计的RC模型。仪器模型通过子电路构建，以代表设计中所使用材料的小单元。只需简单的线性方程即可评估子电路中的RC值。子电路还使用电压控制开关来模拟相变，在相变过程中，λ、C和Δh可在预定温度下瞬间改变值。两种设计的模拟结果能够独立预测仪器对λ和C的灵敏度。模拟输出与测量输出的误差在10%以内。模型模拟显示，在相变过程中，两种设计在热容量测定方面都存在严重误差。同时展示了两种设计中λ、C和Δh之间的相互作用。该技术提供了一种在软件中完全构建、评估和优化量热计设计的方法。
