Gravity-1 solid-propellant carrier rocket utilizes a three-vertical testing and launch mode, and adopts a sea-based launch method. As the demand for satellite launches continues to grow, the scarcity of launch site re...Gravity-1 solid-propellant carrier rocket utilizes a three-vertical testing and launch mode, and adopts a sea-based launch method. As the demand for satellite launches continues to grow, the scarcity of launch site resources,and the consideration of cost savings, the need for rapid testing and launch of carrier rockets has become increasingly strong. The capability of rapid testing and launch has even become one important aspect of evaluating a rocket. This paper focuses on the characteristics of the Gravity-1 solid-propellant strap-on medium-sized carrier rocket and designs and implements a highly reliable, convenient, and intelligent low-cost rapid testing and launch solution. The main aspects include the design of a highly reliable dual-redundant ground architecture and the application of ground-based shelf products.展开更多
Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction...Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction, especially the depth of the bottom cavity. In this study, a ship model experiment of a bulk carrier is conducted in a towing tank using the method of air layer drag reduction (ALDR) with different bottom cavity depths. The shape of the air layer is observed, and the changes in resistance are measured. The model experiments produce results of approximately 20% for the total drag reduction at the ship design speed for a 25-mm cavity continuously supplied with air at Cq = 0.224 in calm water, and the air layer covers the whole cavity when the air flow rate is suitable. In a regular head wave, the air layer is easily broken and reduces the drag reduction rate in short waves, particularly when λ/Lw1 is close to one;however, it still has a good drag reduction effect in the long waves.展开更多
Objective:To observe and analyze the effect of bacterial resistance monitoring in clinical microbiology testing.Methods:600 microbial specimens collected in our hospital in the past year(April 2021 to April 2022)were ...Objective:To observe and analyze the effect of bacterial resistance monitoring in clinical microbiology testing.Methods:600 microbial specimens collected in our hospital in the past year(April 2021 to April 2022)were used as the test subjects of this study.The specimens were divided into Group A(control group)and Group B(research group),with 300 cases in each group.Group A consisted of blood culture specimens,while Group B consisted of sputum specimens.After the tests were completed,the rates of unfavorable and favorable results,bacterial species distribution,and bacterial drug resistance of the specimens in both groups were compared.Results:Among group A specimens,29 cases were positive(9.67%)and 271 cases were negative(90.33%);among group B specimens,99 cases were positive(33.00%)and 201 cases were negative(66.00%);the difference between the two groups of data was statistically significant(P<0.05).As for the distribution of the types of bacteria,there were 472 cases of Gram-negative bacteria and 128 cases of Gram-positive bacteria.Conclusion:Bacterial resistance monitoring is helpful in clinical microbiology testing.Through proper monitoring,bacterial resistance can be well understood.In this way,patients get to receive appropriate treatment measures and suitable antibacterial prescriptions,thereby improving the patient outcome.展开更多
文摘Gravity-1 solid-propellant carrier rocket utilizes a three-vertical testing and launch mode, and adopts a sea-based launch method. As the demand for satellite launches continues to grow, the scarcity of launch site resources,and the consideration of cost savings, the need for rapid testing and launch of carrier rockets has become increasingly strong. The capability of rapid testing and launch has even become one important aspect of evaluating a rocket. This paper focuses on the characteristics of the Gravity-1 solid-propellant strap-on medium-sized carrier rocket and designs and implements a highly reliable, convenient, and intelligent low-cost rapid testing and launch solution. The main aspects include the design of a highly reliable dual-redundant ground architecture and the application of ground-based shelf products.
基金supported by the Ministry of Industry and High Technology Marine Scientific Research Projects(Grant No.2011530)the High Performance Marine Technology Key Laboratory of the Ministry of Education Open Foundation(Grant No.2013033102)
文摘Air lubrication by means of a bottom cavity is a promising method for ship drag reduction. The characteristics of the bottom cavity are sensitive to the flow field around the ship hull and the effect of drag reduction, especially the depth of the bottom cavity. In this study, a ship model experiment of a bulk carrier is conducted in a towing tank using the method of air layer drag reduction (ALDR) with different bottom cavity depths. The shape of the air layer is observed, and the changes in resistance are measured. The model experiments produce results of approximately 20% for the total drag reduction at the ship design speed for a 25-mm cavity continuously supplied with air at Cq = 0.224 in calm water, and the air layer covers the whole cavity when the air flow rate is suitable. In a regular head wave, the air layer is easily broken and reduces the drag reduction rate in short waves, particularly when λ/Lw1 is close to one;however, it still has a good drag reduction effect in the long waves.
文摘Objective:To observe and analyze the effect of bacterial resistance monitoring in clinical microbiology testing.Methods:600 microbial specimens collected in our hospital in the past year(April 2021 to April 2022)were used as the test subjects of this study.The specimens were divided into Group A(control group)and Group B(research group),with 300 cases in each group.Group A consisted of blood culture specimens,while Group B consisted of sputum specimens.After the tests were completed,the rates of unfavorable and favorable results,bacterial species distribution,and bacterial drug resistance of the specimens in both groups were compared.Results:Among group A specimens,29 cases were positive(9.67%)and 271 cases were negative(90.33%);among group B specimens,99 cases were positive(33.00%)and 201 cases were negative(66.00%);the difference between the two groups of data was statistically significant(P<0.05).As for the distribution of the types of bacteria,there were 472 cases of Gram-negative bacteria and 128 cases of Gram-positive bacteria.Conclusion:Bacterial resistance monitoring is helpful in clinical microbiology testing.Through proper monitoring,bacterial resistance can be well understood.In this way,patients get to receive appropriate treatment measures and suitable antibacterial prescriptions,thereby improving the patient outcome.
