Pierce D E, Kim Y, Vig J R
Department of Chemistry, William Patterson University, Wayne, NJ 07470, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 1998;45(5):1238-45. doi: 10.1109/58.726449.
Mass deposition onto a microbalance is generally accompanied by a temperature change. By measuring a single frequency only, it is not possible to separate the frequency change due to mass change from that due to temperature change. In the temperature insensitive microbalance technique, measurements of two frequencies, the fundamental mode and third overtone frequencies of an SC-cut resonator, yield two equations with two unknowns. This allows the separation of mass change effects from temperature change effects. Dual mode excitation can be used for highly accurate resonator self-temperature sensing over wide temperature ranges. SC-cut resonators are also thermal transient compensated. These unique properties allowed the development of a temperature compensated microbalance that is highly sensitive to mass changes, which can be used in rapidly changing thermal environments, over wide temperature ranges, and which requires neither temperature control nor a thermometer other than the resonator. To demonstrate the performance of this microbalance, SC-cut resonators were coated with thin polymethylmethacrylate (PMMA) photoresist films then placed into a UV-ozone cleaning chamber that initially was at about 20 degrees C. When the UV lamp was turned on, the UV-ozone removed PMMA from the surfaces while the chamber temperature rose to about 60 degrees C. The frequency changes due to mass changes could be accurately determined, independently of the frequency changes due to temperature changes.
物质沉积到微量天平上通常会伴随着温度变化。仅通过测量单一频率，无法将因质量变化引起的频率变化与因温度变化引起的频率变化区分开来。在温度不敏感微量天平技术中，对SC切割谐振器的基模频率和第三泛音频率这两个频率进行测量，会得到两个含有两个未知数的方程。这使得能够将质量变化效应与温度变化效应区分开来。双模激励可用于在很宽的温度范围内进行高精度的谐振器自温度传感。SC切割谐振器也进行了热瞬态补偿。这些独特的特性促成了一种对质量变化高度敏感的温度补偿微量天平的开发，这种微量天平可用于快速变化的热环境中，在很宽的温度范围内使用，并且除了谐振器之外既不需要温度控制也不需要温度计。为了展示这种微量天平的性能，将SC切割谐振器涂上聚甲基丙烯酸甲酯（PMMA）光刻胶薄膜，然后放入一个最初温度约为20摄氏度的紫外臭氧清洗室中。当打开紫外灯时，紫外臭氧从表面去除PMMA，同时清洗室温度升至约60摄氏度。能够准确确定因质量变化引起的频率变化，而不受因温度变化引起的频率变化的影响。
