Highly Sensitive Temperature Sensor Based on Coupled-Beam AlN-on-Si MEMS Resonators Operating in Out-of-Plane Flexural Vibration Modes.

This paper reports a type of highly sensitive temperature sensor utilizing AlN-on-Si resonators with coupled-beam structures of double- and triple-ended-tuning-fork (D/TETF). For both resonators, the out-of-plane flexural mode is adopted as it favors the effect of thermal mismatch between the composite layers inherent to the AlN-on-Si structure and thus helps attain a large temperature coefficient of resonant frequency (TCF). The analytical model to calculate TCF values of D/TETF AlN-on-Si resonators is provided, which agrees well with the finite-element simulation and experimental results. The resonant temperature sensor is built by closing the loop of the AlN-on-Si resonator, a transimpedance amplifier, a low-pass filter, and a phase shifter to form an oscillator, the output frequency of which shifts proportionally to the ambient temperature. The measured sensitivities of the temperature sensors using D/TETF resonators are better than -1000 ppm/°C in the temperature range of 25°C~60°C, showing great potential to fulfill the on-chip temperature compensation scheme for cofabricated sensors.

[Potential distribution of Rhodiola crenulata in Tibetan Plateau based on Maxent model].

Wildlife tending and artificial cultivation is an important way to protect the wild resources of Rhodiola crenulata. It is a study hotspot at present. The distribution information of R. crenulata was collected by query data and field survey, the ecological suitability regionalization was conducted based on maximum entropy model combine with ecological factors, including climate, soil and altitude. To provide the reference for production layout, suitable planting area and the selection of artificial planting base by studying the ecological suitability regionalization of R. crenulata. The potential distribution areas mainly concentrated in the easen Tibet, western Sichuan, southern Qinghai, and Gansu Gannan Tibetan Autonomous Prefecture, Yunnan Diqing Tibetan Autonomous Prefecture. There were 5 major environmental factors to have obvious influence on ecology suitability distributions of R. crenulata, including altitude (contribution rate of 61.8%), precipitation of warmest quarter (contribution rate of 19%), the coefficient of variation of precipitation seasonality (contribution rate of 4.7%), the SD of temperature seasonality (contribution rate of 4%), mean temperature of driest quarter (contribution rate of 2.5%). The AUCs of ROC curve were both above 0.9, indicating that the predictive results with the Maxent model were highly precise. The study of the ecological suitability regionalization of R. crenulata based on Maxent can provide a scientific basis for the selection of artificial planting base.

[Study on quality standard of Berberidis Cortex].

In order to establish the quality standard of Berberidis Cortex and improve its quality control level, water, total ash, acid-insoluble ash and alcohol-soluble extract were determined according to procedures recorded in the Chinese Pharmacopoeia (2010 edition). The qualitative and quantitative analyses were performed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) methods. The results showed that TLC identification had a good resolution with clear spots. The water content was 8.39%-12.23%; total ash was 4.50%-9.96%; acid-insoluble ash was 0.10%-0.69%, and the alcohol-soluble extraction was 20.62%-37.13%. The average contents of magnoflorine, jatrorrhizine, palmatine, and berberine in Berberidis Cortex were 5.98%, 0.63%, 0.30%, 2.50%, respectively. It was concluded that the developed method was accurate and good in specificity, which can be used for quality control of Berberidis Cortex in the future.