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:Through quantitative comparison of the gas supply performance of first-stage decompressors of different self-contained underwater breathing apparatus（SCUBA）at home and abroad，to provide a point of reference for the selection，design，and evaluation of SCUBA.Methods:Through the unmanned performance test，the gas supply performance data of first-stage decompressors（14 models）with different input pressures（3.5 MPa，12.0 MPa，20.0 MPa）were recorded，and the distributions of the differences in static outlet pressure，dynamic pressure drop，dynamic and static pressure difference，and maximum gas supply flow were statistically analyzed.Results:The differences in dynamic pressure drop（ P=0.007 at 3.5 MPa， P=0.006 at 12.0 MPa， P=0.034 at 20.0 MPa），dynamic and static pressure difference（ P=0.005 at 3.5 MPa， P=0.002 at 12.0 MPa， P<0.001 at 20.0 MPa）with three input pressures，and the maximum gas supply flow（ P=0.002）with 3.5 MPa input pressure were statistically significant. The differences in static outlet pressure with three input pressures，and the differences in the maximum gas supply flow with 12.0 MPa and 20.0 MPa were not statistically significant（ P>0.05）. Conclusions:The first-stage decompressors of foreign brands show better performance than those of domestic brands in terms of dynamic pressure drop，dynamic and static pressure difference，and maximum gas supply flow.

Objective:To evaluate the thermal insulation performance of a new fast buoyant ascent escape suit in a specific low temperature environment，so as to provide a basis for the subsequent development of the suit and determining the stand-by time on the surface for rescue.Methods:Five subjects in new fast buoyant ascent escape suits were placed in a low temperature environment with water temperature（-1.0 ± 1.0）℃，air temperature（-2.0 ± 1.0）℃ and wind speed（9.0 ± 0.2）m/s . The changes of core body temperature，average body surface temperature，and heart rate were observed，and the participants’ subjective feelings and tolerance periods of time were recorded.Results:The core body temperature，average body surface temperature，and heart rate of the 5 subjects were within normal range. The tolerance periods of time were all more than 6 h，and the longest period of time reached 6.5 h.Conclusion:The thermal insulation performance of the new fast buoyant ascent escape suit can be maintained for more than 6 hours in a specific low-temperature environment，which meets the design requirements.

Objective:To evaluate the thermal insulation performance of a new fast buoyant ascent escape suit in a specific low temperature environment，so as to provide a basis for the subsequent development of the suit and determining the stand-by time on the surface for rescue.Methods:Five subjects in new fast buoyant ascent escape suits were placed in a low temperature environment with water temperature（-1.0 ± 1.0）℃，air temperature（-2.0 ± 1.0）℃ and wind speed（9.0 ± 0.2）m/s . The changes of core body temperature，average body surface temperature，and heart rate were observed，and the participants’ subjective feelings and tolerance periods of time were recorded.Results:The core body temperature，average body surface temperature，and heart rate of the 5 subjects were within normal range. The tolerance periods of time were all more than 6 h，and the longest period of time reached 6.5 h.Conclusion:The thermal insulation performance of the new fast buoyant ascent escape suit can be maintained for more than 6 hours in a specific low-temperature environment，which meets the design requirements.

Objective:Through quantitative comparison of the gas supply performance of first-stage decompressors of different self-contained underwater breathing apparatus（SCUBA）at home and abroad，to provide a point of reference for the selection，design，and evaluation of SCUBA.Methods:Through the unmanned performance test，the gas supply performance data of first-stage decompressors（14 models）with different input pressures（3.5 MPa，12.0 MPa，20.0 MPa）were recorded，and the distributions of the differences in static outlet pressure，dynamic pressure drop，dynamic and static pressure difference，and maximum gas supply flow were statistically analyzed.Results:The differences in dynamic pressure drop（ P=0.007 at 3.5 MPa， P=0.006 at 12.0 MPa， P=0.034 at 20.0 MPa），dynamic and static pressure difference（ P=0.005 at 3.5 MPa， P=0.002 at 12.0 MPa， P<0.001 at 20.0 MPa）with three input pressures，and the maximum gas supply flow（ P=0.002）with 3.5 MPa input pressure were statistically significant. The differences in static outlet pressure with three input pressures，and the differences in the maximum gas supply flow with 12.0 MPa and 20.0 MPa were not statistically significant（ P>0.05）. Conclusions:The first-stage decompressors of foreign brands show better performance than those of domestic brands in terms of dynamic pressure drop，dynamic and static pressure difference，and maximum gas supply flow.

Objective:To study the dynamic air supply peculiarity of the inflation system, by observing the pressure changes of the inflation system, the airbag, and the hood in working mode.Methods:The pressurized chamber for simulation was pressurized to the setting pressure P1 at an exponential rate of . When setting the P1 as 0.2 MPa, 0.7 MPa, 1.1 MPa, 1.6 MPa, and 2.1 MPa, the pressurization time constant b was taken as 30 s, 20 s, 10 s, 7 s, and 4 s respectively. The air supply flow of the inflation system ( Q), the relative pressure in the airbag (Δ P) of the escape immersion suit, and the relative liquid level in the hood (Δ Z) were recorded during the pressurization process, for describing and analyzing the dynamic air supply peculiarity. Results:When the pressure of the simulated pressurized chamber increased to 0.2 MPa, Q increased rapidly and linearly. The functional relation between the linear slope k and b was K=747.81 b-0.26; then a short plateau period of Q appeared with the fluctuation range of 0.9-3.1 kg/h and the pressure range of 0.2-0.4 MPa; after that, Q gradually increased as the environmental pressure increased. The change of the relative pressure in the airbag (Δ P) reflected the regulation process of Q. When pressurized at 0.15 MPa, Δ P increased sharply to the highest value, then it tended to be stable with the increase of the pressure in the simulated pressurized chamber; the higher the P1 was set, the higher Δ P became, but it always remained between 11 kPa and 14 kPa. The functional relation between Δ P and P1 was Δ P= P10.088 4. The relative liquid level in the hood (Δ Z) was the ultimate goal of the air supply of the inflation system. Δ Z was always lower than the liquid level in the simulated pressurized chamber during the pressurization process, and decreased when the pressure of the chamber increased; Δ Z was related to Δ P, and the higher Δ P was, the higher Δ Z was, at the same depth. Conclusion:The airflow of escape immersion suit′s inflation system can match the compress rate of simulated pressurized chamber, and the air supply can be adjusted automatically without manual operation, which can improve the safety of escape.

Objective:To study the dynamic air supply peculiarity of the inflation system, by observing the pressure changes of the inflation system, the airbag, and the hood in working mode.Methods:The pressurized chamber for simulation was pressurized to the setting pressure P1 at an exponential rate of . When setting the P1 as 0.2 MPa, 0.7 MPa, 1.1 MPa, 1.6 MPa, and 2.1 MPa, the pressurization time constant b was taken as 30 s, 20 s, 10 s, 7 s, and 4 s respectively. The air supply flow of the inflation system ( Q), the relative pressure in the airbag (Δ P) of the escape immersion suit, and the relative liquid level in the hood (Δ Z) were recorded during the pressurization process, for describing and analyzing the dynamic air supply peculiarity. Results:When the pressure of the simulated pressurized chamber increased to 0.2 MPa, Q increased rapidly and linearly. The functional relation between the linear slope k and b was K=747.81 b-0.26; then a short plateau period of Q appeared with the fluctuation range of 0.9-3.1 kg/h and the pressure range of 0.2-0.4 MPa; after that, Q gradually increased as the environmental pressure increased. The change of the relative pressure in the airbag (Δ P) reflected the regulation process of Q. When pressurized at 0.15 MPa, Δ P increased sharply to the highest value, then it tended to be stable with the increase of the pressure in the simulated pressurized chamber; the higher the P1 was set, the higher Δ P became, but it always remained between 11 kPa and 14 kPa. The functional relation between Δ P and P1 was Δ P= P10.088 4. The relative liquid level in the hood (Δ Z) was the ultimate goal of the air supply of the inflation system. Δ Z was always lower than the liquid level in the simulated pressurized chamber during the pressurization process, and decreased when the pressure of the chamber increased; Δ Z was related to Δ P, and the higher Δ P was, the higher Δ Z was, at the same depth. Conclusion:The airflow of escape immersion suit′s inflation system can match the compress rate of simulated pressurized chamber, and the air supply can be adjusted automatically without manual operation, which can improve the safety of escape.

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 .