排序方式: 共有34条查询结果,搜索用时 156 毫秒
1.
科学史就是用历史学的方法对科学的进程进行重构。在这个重构过程中,人们研究很多的是科学内史和科学外史的方法区分及其运用,认为对"科学"的不同界定,决定了对科学的进程及进行重构的方法的选取。 相似文献
2.
3.
4.
At present,spark plugs are used to trigger discharge in pulsed plasma thrusters (PPT),which are known to be life-limiting components due to plasma corrosion and carbon deposition.A strong electric field could be formed in a cathode triple junction (CTJ) to achieve a trigger function under vacuum conditions.We propose an induction-triggered electrode structure on the basis of the CTJ trigger principle.The induction-triggered electrode structure could increase the electric field strength of the CTJ without changing the voltage between electrodes,contributing to a reduction in the electrode breakdown voltage.Additionally,it can maintain the plasma generation effect when the breakdown voltage is reduced in the discharge experiments.The induction-triggered electrode structure could ensure an effective trigger when the ablation distance of Teflon increases,and the magnetic field produced by the discharge current could further improve the plasma density and propagation velocity.The induction-triggered coaxial PPT we propose has a simplified trigger structure,and it is an effective attempt to optimize the micro-satellite thruster. 相似文献
5.
6.
7.
8.
9.
胃蛋白酶提取硫酸软骨素工艺优化 总被引:3,自引:0,他引:3
以牛喉管为原料,采用超声波辅助碱-双酶(木瓜蛋白酶、胃蛋白酶)法提取硫酸软骨素。通过单因素试验、正交试验优化胃蛋白酶酶解硫酸软骨素的工艺。结果显示:当pH值为5.9、胃蛋白酶添加量为1.4:1000(m/V)、酶解温度40℃、酶解时间为100min时,产品最高得率可达25.43%,纯度达到87.96%。 相似文献
10.