Objective To quantitatively compare the gas supply performance between balanced piston and balanced diaphragm first-stage pressure reducers,so as to provide reference data for establishing a diving apparatus evaluation system.Methods The gas supply performance test data of the type 15 first-stage pressure reducer under different input pressures were obtained through the unmanned performance test.Dynamic pressure drop,dynamic and static pressure difference,and maximum gas-supply flow rate were compared.Results There were statistical differences in dynamic pressure drop,dynamic and static pressure difference,and maximum gas supply flow rate between the 2 kinds of first-stage pressure reducers.The maximum supply flow rate linear regression model of balanced piston first-stage pressure reducers could explain 92.3%of the changes of the maximum supply flow.Conclusion The balanced piston first-stage pressure reducer is superior to the balanced diaphragm first-stage pressure reducer in dynamic pressure drop,dynamic and static pressure difference,and maximum air supply flow rate,but the internal isolation of the balanced diaphragm first-stage pressure reducer makes it more suitable for use in cold or dirty waters.

Objective:To understand the status of outpatients′medical care and their impact on the doctor -pa-tient trust in Beijing .Methods:Three tertiary hospitals were selected due to most concentrated high -quality medi-cal resources , the largest number of patient visits , universalism and particularism trust could be compared , taking field observations , personal interviews and questionnaires methods .Results:The main factors affecting clinical doctor-patient trust are time, the doctor skills, medical ethics, medical and prescription drug division , etc.are appropriate and effective .Conclusion:Play the role of pyramidmedical system′s overall effectiveness , and es-tablish a patient-centered system for outpatient care as soon as possible a comprehensive grasp of the overall con -struction team doctor , continue to strengthen the standardized management of medication .