ABSTRACT
Recently, due to the development of automation technology, torque measuring and monitoring technologies have been brought to the focus. However, the commercially available sensors have the disadvantage of large volume, which results in the difficulty of installation on existing automated machines. Responding to the above-mentioned problem, a contactless torque sensor that uses an electromagnetic coil combined with a permanent magnet was proposed. By adjusting the input electric current in the coil, the strength of the magnetic field can be controlled to generate a non-contact magnetic force to resist external torque loading. For the measurement of such a magnetic force, a cantilever-beam mechanism comprising a piezoelectric-loading (PZT-L) sensor is employed to estimate the external static force by measuring the variation of the electric impedance. According to the measured results, the proposed PZT-L sensor demonstrates the accuracy of the proposed design, for which the maximum estimated error was around 6%. Finally, the proposed contactless torque sensor with 11 cm in diameter and 2 cm in thickness was employed to verify the effectiveness of theoretical analysis. From the sensor characteristic measurement, the detection range for external torque can be from 7.8 to 125.6 N-mm when the driven current input ranged from 2 to 10 A. Therefore, the experimental results presented that the moment of inertia via the resisted torque can be adjusted by the proposed non-contact torque-sensing system according to the measuring condition.
ABSTRACT
Objective::To observe the clinical efficacy of Gandouling decoction on hepatic function of patients with phlegm and blood stasis type Wilson's disease. Method::From January 2015 to December 2017, totally 72 cases of phlegm and blood stasis type Wilson's disease admitted to Encephalopathy Center in the First Affiliated Hospital of Anhui University of Chinese Medicine were randomly divided into treatment group and control group, with 36 cases in each group. Patients in both groups were injected with sodium dimercaptopropane sulfonate for routine treatment. At the same time, patients in control group received Hugan Tablets, and patients in treatment group received Gandouling decoction for a total of 6 treatment courses. Before and after treatment, traditional Chinese medicine(TCM)syndrome effective rate, serum enzyme index [alanine aminotransferase(ALT), aspartate aminotransferase (AST), alkaline phosphatase(AKP)], bilirubin metabolism index [total bilirubin(TBIL)], liver fibrosis index [laminin(LN), hyaluronic acid(HA), collagen type IV(CⅣ), procollagen type Ⅲ peptide(PⅢP)]and blood coagulation index [fibrinogen (FBG), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) ]were observed. Result::TCM syndrome effective rates of treatment group and control group were 86.11%(31/36) and 63.98%(23/36) respectively, with a significant difference between two groups (P<0.05). ALT, AST, AKP, TBIL decreased in two groups after treatment (P<0.01), and the effects of ALT, AST, AKP, TBIL in treatment group were significantly better than those in control group (P<0.01), liver fibrosis index decreased in both groups after treatment (P<0.01), and the effect in treatment group was significantly better than that in control group (P<0.01). Blood coagulation indexes were improved to different degrees in both groups (P<0.05, P<0.01), and there were significant differences between treatment group and control group in decreasing PT, APTT, TT levels (P<0.05, P<0.01) and increasing FBG level (P<0.01). Conclusion::Gandouling decoction can significantly improve hepatic function of patients with phlegm and blood stasis type Wilson's disease, which is manifested in improving serum enzymes and bilirubin indexes, reversing liver fibrosis, promoting clotting factors and reducing bleeding tendency, in order to delay the progress of the disease and improve the life quality of patients.
ABSTRACT
This paper aims to provide an alternative method to determine the characteristics of a piezoelectric transducer from measurement. A block diagram approach is proposed to analyze the dynamic characteristics of a thickness-mode piezoelectric transducer at its resonance frequency. Based on the feedback loop framework, the input-output relations of the electromechanical interaction of the transducer are described in terms of linear block diagram models. Furthermore, the closed-loop relations from external force to vibration velocity and electric current from generated voltage are easily found by Mason's rule to characterize the equivalent mechanical admittance and electrical impedance, respectively. An example of a Langevin transducer with 28.15kHz resonance frequency is illustrated for dynamics analysis. The frequency responses of the piezoelectric transducer, resulting from a force and current input, are respectively measured to identify the system parameters of the feedback model. The experimental results demonstrate the effectiveness of the proposed method.
