The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personn...The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personnel from firing artillery within the cab.To investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing condition.For comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant discontinuity.The enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude overpressure.The frameskin structure helps attenuate the impact of muzzle blast on the FFICC.Conversely,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.展开更多
Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment ...Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.展开更多
Based on the comprehensive research on core samples,well testing data and fluid parameters of the reservoirs,the depositional architecture of the abnormal low pressure compartment and fluid characteristics of Huatugou...Based on the comprehensive research on core samples,well testing data and fluid parameters of the reservoirs,the depositional architecture of the abnormal low pressure compartment and fluid characteristics of Huatugou oilfield of Qaidam basin were reported,and the correlation between the compartment and hydrocarbon accumulation was revealed. The result indicates that the reservoirs are located展开更多
Acute compartment syndrome （ACS） usually occurs after an injury to a limb or other adjacent organ, when there is insufficient blood supply to muscles and nerves due to swelling and increased pressure within a body c...Acute compartment syndrome （ACS） usually occurs after an injury to a limb or other adjacent organ, when there is insufficient blood supply to muscles and nerves due to swelling and increased pressure within a body compartment. Classically, there are six symptoms and signs associated with ACS, all of which have an initial letter ＇P＇： pain, paresthesia, pallor, paralysis, pulselessness and poik- ilothermia The complexities of the clinical diag- nosis and management of ACS remain a challeng- ing oroblem for orthooedic surgeons.展开更多
目的探讨MRI分区定位联合经直肠B超引导前列腺穿刺活检在前列腺癌诊断中的临床应用价值。方法对50例临床前列腺特异抗原(prostate specific antigen,PSA)升高患者行MRI检查并进行12分区,分区与经直肠B超引导穿刺方向、区域一致,然后行...目的探讨MRI分区定位联合经直肠B超引导前列腺穿刺活检在前列腺癌诊断中的临床应用价值。方法对50例临床前列腺特异抗原(prostate specific antigen,PSA)升高患者行MRI检查并进行12分区,分区与经直肠B超引导穿刺方向、区域一致,然后行经直肠前列腺穿刺术,即在传统穿刺的基础上,增加MRI分区异常区域的穿刺点。统计传统穿刺和传统穿刺联合MRI可疑分区穿刺的前列腺癌阳性率。结果 MRI可疑分区联合传统穿刺前列腺癌阳性率高于传统穿刺(42.0%vs 36.0%,P<0.05)。联合穿刺并发血尿5例,大便带血13例,发热1例,无其他严重并发症。结论 MRI分区定位联合经直肠B超引导前列腺穿刺活检有利于提高前列腺癌穿刺阳性率。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2341269)。
文摘The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery firing.This overpressure is the primary factor preventing personnel from firing artillery within the cab.To investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing condition.For comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant discontinuity.The enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude overpressure.The frameskin structure helps attenuate the impact of muzzle blast on the FFICC.Conversely,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.
基金This research was supported by the National Natural Science Foundation of China(Grant No.11472115,11872214)the China Scholarship Council(201706845026).
文摘Liquid-filled compartment structure consists of a bulk steel plate with matrix blind holes which are filled with liquid and a steel front plate to seal up the liquid with rings and bolts.The liquid-filled compartment structure can resist the shaped charge warhead effectively.This paper presents experimental and theoretical investigations of the penetration ability of the residual shaped charge jet emerging from the liquid-filled compartment structure after the penetration process at different impact angles.On the basis of shock wave propagation theory,the influence of the liquid-filled compartment structure on jet stability is analysed.The interferences of the liquid backflow caused by a reflected shock wave and a back plate on jet stability under different impact angles are also examined.In addition,the range of the disturbed velocity segments of the jet at different impact angles and the penetration ability of the residual jet are obtained.A theoretical model is validated against the experimental penetration depths.
文摘Based on the comprehensive research on core samples,well testing data and fluid parameters of the reservoirs,the depositional architecture of the abnormal low pressure compartment and fluid characteristics of Huatugou oilfield of Qaidam basin were reported,and the correlation between the compartment and hydrocarbon accumulation was revealed. The result indicates that the reservoirs are located
文摘Acute compartment syndrome （ACS） usually occurs after an injury to a limb or other adjacent organ, when there is insufficient blood supply to muscles and nerves due to swelling and increased pressure within a body compartment. Classically, there are six symptoms and signs associated with ACS, all of which have an initial letter ＇P＇： pain, paresthesia, pallor, paralysis, pulselessness and poik- ilothermia The complexities of the clinical diag- nosis and management of ACS remain a challeng- ing oroblem for orthooedic surgeons.
