In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted....In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted. The relationships between the above three characteristics have been researched. The evolution of the cavity can be divided into three processes according to its shape characteristics. The first liquid spurt occurred in Process Ⅱ and the rest of it occurred in Process Ⅲ. The duration of the second liquid spurt is longer than the first liquid spurt. When the impact velocity of the fragment is less than996 m/s, the velocity of the second liquid spurt is the highest. When the velocity of the fragment is greater than 996 m/s, the velocity of the first liquid spurt is the highest. The maximum velocities of the first and second liquid spurt are 111 m/s and 94 m/s respectively. The pressure fluctuated sharply in Processes Ⅰ and Ⅲ. The maximum peak pressures in the shock and the cavity oscillation phases are15.51 MPa and 7.96 MPa respectively. The time interval of the two adjacent pressure pulses increases with the increase of the fragment velocity.展开更多
基金the National Natural Science Foundation of China(Grant No.11572159)the National Defense Science and Technology Foundational Enhancement Program Technology Field Foundation(No.2020-JCJQ-JJ-401)for providing the financial support for this study.
文摘In research of the characteristics of the cavity evolution, the pressure, and the liquid spurt in hydrodynamic ram, the experiment of the high-velocity fragment impacting the water-filled container had been conducted. The relationships between the above three characteristics have been researched. The evolution of the cavity can be divided into three processes according to its shape characteristics. The first liquid spurt occurred in Process Ⅱ and the rest of it occurred in Process Ⅲ. The duration of the second liquid spurt is longer than the first liquid spurt. When the impact velocity of the fragment is less than996 m/s, the velocity of the second liquid spurt is the highest. When the velocity of the fragment is greater than 996 m/s, the velocity of the first liquid spurt is the highest. The maximum velocities of the first and second liquid spurt are 111 m/s and 94 m/s respectively. The pressure fluctuated sharply in Processes Ⅰ and Ⅲ. The maximum peak pressures in the shock and the cavity oscillation phases are15.51 MPa and 7.96 MPa respectively. The time interval of the two adjacent pressure pulses increases with the increase of the fragment velocity.
文摘目的测定市场上所售喷码鸡蛋所用喷码油墨的主要成分,为食品安全监管提供数据支撑。方法采用高效液相色谱仪(high performance liquid chromatography,HPLC)、超高效液相色谱-离子阱-飞行时间串联质谱仪(ultra high performance liquid chromatography-ion trap-time of flight tandem mass spectrometry,UPLC-MS-IT-TOF)和气相色谱仪(gas chromatography,GC)对鸡蛋喷码油墨的着色剂和溶剂进行成分分析;采用原子吸收仪(atomic absorption spectrometer,AAS)和原子荧光仪(atomic fluorescence spectrometer,AFS)对油墨中可溶性元素进行定性定量分析。结果市场上所售喷码鸡蛋所用喷码油墨的着色剂大部分为GB2760-2014《食品安全国家标准食品添加剂使用标准》规定中允许使用的"赤藓红"和"亮蓝",溶剂为允许使用的助剂丙酮和乙醇,但个别企业采用的喷码油墨为食品中禁止使用的工业染料"溶剂红49"。当喷码油墨着色剂为食品级"赤藓红"时,生鸡蛋及蒸煮鸡蛋的蛋白和蛋黄里均无喷码用着色剂,蛋壳表面着色剂含量为0.2~2.0 mg/kg,远低于其在食品中允许使用的最大限量值;当喷码油墨着色剂为"溶剂红49"时,鸡蛋的可食用部分均未检出"溶剂红49",但鸡蛋壳、煮鸡蛋的水、与鸡蛋同蒸的馒头中,均检出不同含量的"溶剂红49"。结论市场上所售大多数喷码鸡蛋所用油墨不会给人体健康带来安全风险,但个别企业采用的喷码油墨为食品国家标准禁止使用的工业染料,虽单个鸡蛋表面油墨含量较少,但食用采用这种喷码油墨的鸡蛋可能会危害人体健康,建议相关管理部门加强监管,从源头上避免该现象的发生,保障消费者的食品安全。
