To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was esta...To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was established based on the theory of bionic dimpled drag reduction and the principle of rubber sealing. In condition that the bionic dimpled characteristic diameters were 1, 2, 3, 4, and 5 mm, respectively, by numerical simulation, the influence of the installing compression of the rubber sealing ring on its surface stress and deformation was analyzed, and sealing performance of the rubber ring with different diameters of bionic dimpled was studied. The results show that the deformation of rubber ring appears prominent nonlinear characteristics when compression is increased from 1.5 mm to 2.5 ram. When the compression is 2.5 mm, the equivalent compression stress on the sealing areas of both sides of the rubber seal is greater than the working pressure of aerodynamic extinguishing cannon, which could meet the sealing requirement and would not cause leakage. So the rubber sealing ring with bionic dimpled surface possesses a good sealing characteristic and has no negative effect on the sealing of shell body; When the compression is 2.5 mm, the larger equivalent stress on the edge of sealing ring and the more even stress distribution in the high pressure area are generated due to the smaller compressive stress on the bionic dimple areas, which lays a foundation for the drag reduction characteristics of the shell body＇s rubber ring with bionic dimpled surface.展开更多
Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of ...Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of the face, the top coal is in front of sideabutment pressure concentration increase area at this time, and the top coal horizontaldisplacement increase rapidly.Also analyzed the top coal mechanical properties, and thetop coal under abutment pressure turned into block state.Finally, analyzed the top coalfailure mechanism and the structure of the mechanical model, and also made a theoreticalanalysis of the top coal's ultimate bearing capacity.展开更多
To unify different seismic geometries, the concept of generalized offset is defined and the expressions for Fresnel zones of different order on a plane are presented. Based on wave theory, the equation of the lateral ...To unify different seismic geometries, the concept of generalized offset is defined and the expressions for Fresnel zones of different order on a plane are presented. Based on wave theory, the equation of the lateral wave-field stacking for generalized-offset Fresnel zones is derived. For zero and nonzero offsets, the lateral stacking amplitude of diffraction bins of different sizes is analyzed by referring to the shape of the Fresnel zones of different order. The results suggest the following. First, the contribution of diffraction bins to wave- field stacking is related to the offset, surface relief, interface dip, the depth of the shot point to the reflection interface, the observational geometry, and the size of the interference stacking region. Second, the first-order Fresnel zone is the main constructive interference, and its contribution to the reflection amplitude is slightly smaller than half the contribution of all Fresnel zones. Finally, when the size of the diffraction bin is smaller than the first- order Fresnel zone, the larger the size of the diffraction bin, the larger is the amplitude of the receiver, even in the nonzero offset-case.展开更多
A photoelectric equipment for inspecting artillery bore is composed of digital display grating sensor and data processing with computer.It can replace the traditional mechanical measurer and realize the automatic insp...A photoelectric equipment for inspecting artillery bore is composed of digital display grating sensor and data processing with computer.It can replace the traditional mechanical measurer and realize the automatic inspection of artillery bore.Introduced are briefly the working principles and analysis of this device.展开更多
Objective: To investigate pathological characteristics of gunshot wounds concomitant seawater immersion in rabbits’ femoral arteries. Methods: Thirty rabbits were divided randomly into 3 groups: simple gunshot-wound ...Objective: To investigate pathological characteristics of gunshot wounds concomitant seawater immersion in rabbits’ femoral arteries. Methods: Thirty rabbits were divided randomly into 3 groups: simple gunshot-wound group (Group I, n=10), gunshot wound with seawater immersion for 30 mins (Group II, n=10), and 60 mins group (Group III, n=10). Femoral arteries were impacted by (0.38 g) steel spheres fired with a (7.62 mm) rifle. After being wounded, rabbits in Groups II and III were immersed in seawater for 30 or 60 mins, but those in Group I were not. At 2, 4, 6, 8, 12 hours following injury, a 40 mm segment of the artery on each side of the gunshot point were excised and observed by light and electron microscopy. Results: The patterns of arterial injuries were mainly contusion and transection. Completely transected artery was classified as primary-wound-tract area, contused area and shocked area. Compared with those in Group I, the primary-wound-tract and contused areas in Group II manifested obvious swelling in the arterial wall especially at the outside 2/3 of the media. Vacuolar structures were often seen in smooth muscle cells of the media. Intercellular space among the smooth muscle cells were filled with homogeneous acidophilic substances. Deep rugae among endothelial cells flattened or rugal folds lost their longitudinal orientation, and marked fibrin and platelet deposition were noticed. No significant difference was detected between Group II and III. The pathological changes in the shocked area were similar in 3 groups. Conclusions: For gunshot wounds concomitant seawater immersion in rabbits’ femoral arteries, there was a marked swelling of cells and intercellular space in primary-wound-tract area and contusion area. The influence of these pathological changes on surgical reparation deservers further study.展开更多
基金Project(51275102)supported by the National Natural Science Foundation of ChinaProject(159070220011)supported by the Science and Technology Innovative Research Programs Foundation of Harbin city,ChinaProject(HEUCF110702)supported by the Fundamental Research Funds for the Central Universities of China
文摘To solve the problem of sealing between the barrel and the rubber ring of shell body during an launching process of aerodynamic extinguishing cannon, a rubber sealing model with bionic dimpled characteristics was established based on the theory of bionic dimpled drag reduction and the principle of rubber sealing. In condition that the bionic dimpled characteristic diameters were 1, 2, 3, 4, and 5 mm, respectively, by numerical simulation, the influence of the installing compression of the rubber sealing ring on its surface stress and deformation was analyzed, and sealing performance of the rubber ring with different diameters of bionic dimpled was studied. The results show that the deformation of rubber ring appears prominent nonlinear characteristics when compression is increased from 1.5 mm to 2.5 ram. When the compression is 2.5 mm, the equivalent compression stress on the sealing areas of both sides of the rubber seal is greater than the working pressure of aerodynamic extinguishing cannon, which could meet the sealing requirement and would not cause leakage. So the rubber sealing ring with bionic dimpled surface possesses a good sealing characteristic and has no negative effect on the sealing of shell body; When the compression is 2.5 mm, the larger equivalent stress on the edge of sealing ring and the more even stress distribution in the high pressure area are generated due to the smaller compressive stress on the bionic dimple areas, which lays a foundation for the drag reduction characteristics of the shell body＇s rubber ring with bionic dimpled surface.
文摘Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of the face, the top coal is in front of sideabutment pressure concentration increase area at this time, and the top coal horizontaldisplacement increase rapidly.Also analyzed the top coal mechanical properties, and thetop coal under abutment pressure turned into block state.Finally, analyzed the top coalfailure mechanism and the structure of the mechanical model, and also made a theoreticalanalysis of the top coal's ultimate bearing capacity.
基金financially supported by the National"Five"major projects(Grant No.2011ZX05024-001)
文摘To unify different seismic geometries, the concept of generalized offset is defined and the expressions for Fresnel zones of different order on a plane are presented. Based on wave theory, the equation of the lateral wave-field stacking for generalized-offset Fresnel zones is derived. For zero and nonzero offsets, the lateral stacking amplitude of diffraction bins of different sizes is analyzed by referring to the shape of the Fresnel zones of different order. The results suggest the following. First, the contribution of diffraction bins to wave- field stacking is related to the offset, surface relief, interface dip, the depth of the shot point to the reflection interface, the observational geometry, and the size of the interference stacking region. Second, the first-order Fresnel zone is the main constructive interference, and its contribution to the reflection amplitude is slightly smaller than half the contribution of all Fresnel zones. Finally, when the size of the diffraction bin is smaller than the first- order Fresnel zone, the larger the size of the diffraction bin, the larger is the amplitude of the receiver, even in the nonzero offset-case.
文摘A photoelectric equipment for inspecting artillery bore is composed of digital display grating sensor and data processing with computer.It can replace the traditional mechanical measurer and realize the automatic inspection of artillery bore.Introduced are briefly the working principles and analysis of this device.
文摘Objective: To investigate pathological characteristics of gunshot wounds concomitant seawater immersion in rabbits’ femoral arteries. Methods: Thirty rabbits were divided randomly into 3 groups: simple gunshot-wound group (Group I, n=10), gunshot wound with seawater immersion for 30 mins (Group II, n=10), and 60 mins group (Group III, n=10). Femoral arteries were impacted by (0.38 g) steel spheres fired with a (7.62 mm) rifle. After being wounded, rabbits in Groups II and III were immersed in seawater for 30 or 60 mins, but those in Group I were not. At 2, 4, 6, 8, 12 hours following injury, a 40 mm segment of the artery on each side of the gunshot point were excised and observed by light and electron microscopy. Results: The patterns of arterial injuries were mainly contusion and transection. Completely transected artery was classified as primary-wound-tract area, contused area and shocked area. Compared with those in Group I, the primary-wound-tract and contused areas in Group II manifested obvious swelling in the arterial wall especially at the outside 2/3 of the media. Vacuolar structures were often seen in smooth muscle cells of the media. Intercellular space among the smooth muscle cells were filled with homogeneous acidophilic substances. Deep rugae among endothelial cells flattened or rugal folds lost their longitudinal orientation, and marked fibrin and platelet deposition were noticed. No significant difference was detected between Group II and III. The pathological changes in the shocked area were similar in 3 groups. Conclusions: For gunshot wounds concomitant seawater immersion in rabbits’ femoral arteries, there was a marked swelling of cells and intercellular space in primary-wound-tract area and contusion area. The influence of these pathological changes on surgical reparation deservers further study.
