Objective:To establish an HPLC method for the determination of ephedrine hydrochloride and amygdalin in Kangzhi syrup. Methods:The separation was performed on a Waters ODS2(250 mm×4.6 mm,5 μm) column. The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(containing 0.1% triethylamine) with gradient elution,the detection wavelength was at 205 nm,the flow rate was 1.0 ml·min-1,and the column temperature was 30℃. Results: Ephedrine hydrochloride and amygdalin was linear within the range of 0.169-3.380 μg(r=0.999 9)and 0.141-2.820 μg(r=0.999 7), respectively.The average recovery of e-phedrine hydrochloride and amygdalin was 98.8% and 99.1% with the RSD of 1.93% and 1.22%(n=6), respectively.Conclu-sion:The method is rapid and accurate for the simultaneous analysis of ephedrine hydrochloride and amygdalin, which can provide a reliable way for the quality control for Kangzhi syrup.

ObjectiveTo propose a three-degree-of-freedom model of electric wheelchair, to optimize the steering stability of the wheelchair. MethodsBased on the two degrees of freedom vehicle model and considering the influence of body inertia and lateral wind, the wheelchair roll angle was introduced to establish the three degrees of freedom steering model of wheelchair. The lateral velocity, centroid sideslip angle, yaw rate and body roll angle response of the motor angular velocity input under different working conditions were simulated and analyzed respectively. Taking KS2 electric wheelchair as an example, the wheelchair steering experiment was designed to verify the rationality and feasibility of the model, and the optimization effect of the model algorithm on the wheelchair handling and stability. ResultsThe maneuverability and stability of the electric wheelchair with three degrees of freedom model algorithm were significantly improved, and the response curve was smoother. The smaller the |V_L-V_R|/t was, the better the handling stability was when the left and right motors of the wheelchair had the same steering direction. When |V_L-V_R|/t was the same, the steering maneuverability was better on the reverse rotation of the motor, but the handling stability also decreased. ConclusionThe simulation analysis is in good agreement with the experimental results, which verifies that the model is reasonable and feasible. The model algorithm can better optimize the handling stability of electric wheelchairs, and can be generally applied to study and analyze the handling stability of different wheelchairs when they turn.