In this paper the hit force of firing bullet on bulletproof helmet has been computed and the test device has been described. The device is divided into two parts: 1) The bullet, helmet and mould are in one system, u...In this paper the hit force of firing bullet on bulletproof helmet has been computed and the test device has been described. The device is divided into two parts: 1) The bullet, helmet and mould are in one system, using moment theorem to calculate the hit force; 2) The mould, sensor and support pole are in one system, using the method in reference [1] that measures the dynamic strain and displacement of simulate target of bulletproof clothes. We compute the transfigure energy and momentum energy when hitting the mould, the work done by the sensor and the expend energy of support pole. We get the hit force of helmet using energy balance principle. The result is according with the test and has been used to design the GGK93T bulletproof helmet and other serial products.展开更多
The hydrodynamic lifting force acting on a gate with high head is one of the key factors concerning the safety and reliability of gates. The lifting force is closely related to hydrodynamic pressure, and generally, is...The hydrodynamic lifting force acting on a gate with high head is one of the key factors concerning the safety and reliability of gates. The lifting force is closely related to hydrodynamic pressure, and generally, is obtained through the model test. This work presents a method of numerical simulation based on the VOF method for the flow and FEM for the structure of a gate to investigate this kind of the lifting force. The physical model experiments were conducted about the hydrodynamic pressure and the lifting force to verify the numerical results. The comparisons of those two methods show that the maximum relative error is smaller than 11.40 % and the method presented in this paper is feasible and could be used in the designs of hydropower projects.展开更多
咬合力是动物生态适应性的重要体现,而形态特征通常能反映咬合力的大小。为研究红耳龟Trachemys scripta elegans咬合力性二型及其与形态的关系,采用力值传感器测定了雌性(n=16)和雄性(n=14)红耳龟的咬合力,分析了雌雄个体间咬合力的差...咬合力是动物生态适应性的重要体现,而形态特征通常能反映咬合力的大小。为研究红耳龟Trachemys scripta elegans咬合力性二型及其与形态的关系,采用力值传感器测定了雌性(n=16)和雄性(n=14)红耳龟的咬合力,分析了雌雄个体间咬合力的差异及其与形态指标(体质量、背甲长、头长、头宽、头高)的相关性。结果显示,雌性红耳龟的咬合力(71.92 N±15.59 N)显著大于雄性(55.24 N±10.09 N)(P=0.047);雌性红耳龟体质量、背甲长和头宽也显著大于雄性;咬合力与形态存在显著的线性关系(P<0.05)。结果表明,红耳龟的咬合力具有性二型,咬合力的分化可能与形态特征的性二型有关。雌性红耳龟较大的咬合力有助于提高取食效率,以满足大体型及繁殖的能量需求,从而提高了自身的适合度。展开更多
Foot pressure measurements were performed during standing and level walkingon a series of 30 normal subjects (15 males, 15 females, a total of 60 feet) with amean age of 37.6 yrs and a mean body weight of 66.3 kg. A s...Foot pressure measurements were performed during standing and level walkingon a series of 30 normal subjects (15 males, 15 females, a total of 60 feet) with amean age of 37.6 yrs and a mean body weight of 66.3 kg. A significant difference wasfound in the peak pressure under the second metatarsal head between males and femaleswith females showing higher pressures than males daring walking (P【0. 01). The meanpeak pressure and standard deviation for all 7 areas selected for 30 adult subjects duringstanding and walding were obtained. The rise time to peak pressure at each selected areafor walking was recorded and analysed. The practical application and clinical significanceof these data were also discussed.展开更多
Injuries caused by blunt force are seen frequently in daily forensic casework.Sometimes,especially when there is less information about the surrounding circumstances,it might become difficult to figure out the cause a...Injuries caused by blunt force are seen frequently in daily forensic casework.Sometimes,especially when there is less information about the surrounding circumstances,it might become difficult to figure out the cause and background of injuries:accident,criminal violence or self-infliction?In the study presented,face injuries caused by blunt force in 694 cases were analyzed comparing the injury patterns in accidents to those in crimes.It turned out injuries of the ear and retroauricular region clearly indicate a crime.Also,soft tissue injuries of nose,upper jaw,and lower jaw point towards a criminal violence,whereas tooth injuries occur with a similar frequency in both crimes and accidents.展开更多
Taking the combustor composite structure of a high-strength diesel engine as the main research object,dedicated tests have been conducted to verify the accuracy of three distinct cylinder gasket pressure simulation mo...Taking the combustor composite structure of a high-strength diesel engine as the main research object,dedicated tests have been conducted to verify the accuracy of three distinct cylinder gasket pressure simulation models.Using the measured cylinder gasket compression rebound curve,a gasket unit has been designed and manufactured.For this unit,the influence of the bolt pretension,cylinder body and cylinder head material on gasket sealing pressure has been investigated systematically in conditions of thermo-mechanical coupling.The results show that the bolt pretension force is one of the most important factors affecting the cylinder gasket sealing pressure.The change of the body material has little effect on this pressure.The cylinder gasket seal pressure decreases progressively with the reduction of the elastic module of the cylinder head material.展开更多
文摘In this paper the hit force of firing bullet on bulletproof helmet has been computed and the test device has been described. The device is divided into two parts: 1) The bullet, helmet and mould are in one system, using moment theorem to calculate the hit force; 2) The mould, sensor and support pole are in one system, using the method in reference [1] that measures the dynamic strain and displacement of simulate target of bulletproof clothes. We compute the transfigure energy and momentum energy when hitting the mould, the work done by the sensor and the expend energy of support pole. We get the hit force of helmet using energy balance principle. The result is according with the test and has been used to design the GGK93T bulletproof helmet and other serial products.
基金supported by the National Natural Science Foundation of China (Grant No.51079044)
文摘The hydrodynamic lifting force acting on a gate with high head is one of the key factors concerning the safety and reliability of gates. The lifting force is closely related to hydrodynamic pressure, and generally, is obtained through the model test. This work presents a method of numerical simulation based on the VOF method for the flow and FEM for the structure of a gate to investigate this kind of the lifting force. The physical model experiments were conducted about the hydrodynamic pressure and the lifting force to verify the numerical results. The comparisons of those two methods show that the maximum relative error is smaller than 11.40 % and the method presented in this paper is feasible and could be used in the designs of hydropower projects.
文摘Foot pressure measurements were performed during standing and level walkingon a series of 30 normal subjects (15 males, 15 females, a total of 60 feet) with amean age of 37.6 yrs and a mean body weight of 66.3 kg. A significant difference wasfound in the peak pressure under the second metatarsal head between males and femaleswith females showing higher pressures than males daring walking (P【0. 01). The meanpeak pressure and standard deviation for all 7 areas selected for 30 adult subjects duringstanding and walding were obtained. The rise time to peak pressure at each selected areafor walking was recorded and analysed. The practical application and clinical significanceof these data were also discussed.
基金supported by a grant of the Interdisciplinary Centre for Clinical Research IZKF of Julius-MaximiliansUniversity of Wurzburg.
文摘Injuries caused by blunt force are seen frequently in daily forensic casework.Sometimes,especially when there is less information about the surrounding circumstances,it might become difficult to figure out the cause and background of injuries:accident,criminal violence or self-infliction?In the study presented,face injuries caused by blunt force in 694 cases were analyzed comparing the injury patterns in accidents to those in crimes.It turned out injuries of the ear and retroauricular region clearly indicate a crime.Also,soft tissue injuries of nose,upper jaw,and lower jaw point towards a criminal violence,whereas tooth injuries occur with a similar frequency in both crimes and accidents.
基金the Medium and Heavy Duty High Power-Density Clean Energy Power of National 863 Project。
文摘Taking the combustor composite structure of a high-strength diesel engine as the main research object,dedicated tests have been conducted to verify the accuracy of three distinct cylinder gasket pressure simulation models.Using the measured cylinder gasket compression rebound curve,a gasket unit has been designed and manufactured.For this unit,the influence of the bolt pretension,cylinder body and cylinder head material on gasket sealing pressure has been investigated systematically in conditions of thermo-mechanical coupling.The results show that the bolt pretension force is one of the most important factors affecting the cylinder gasket sealing pressure.The change of the body material has little effect on this pressure.The cylinder gasket seal pressure decreases progressively with the reduction of the elastic module of the cylinder head material.
