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The impact force that is generated with the the transducing sheet is saturated with laser energy density increasing, this has the practical value: When the laser impact force amplitude reaches a threshold value required for transdermal delivery and close to the saturation intensity, if we add the laser energy, the amplitude of the Impact force does not increase significantly. This reduces the accuracy of the laser energy control requirements and can help protect the skin from damage. But In the case of the larger defocus degree, the oscillation of Impact force amplitude increasing when we add the laser energy make it unsuitable for clinical practice.
This paper study the laser transducing sheet. Its structural is designed a set including constrained layer, absorbing layer, protective layer and a liquid box integration "insert". The total thickness is about 1.3 mm and the diameter is 12 mm. The transducing sheet has the advantage of compact structure and is easy to fulfill the design requirement of clinical disposable. It also has other advantages of easy assembly and disassembly, convenient mass production and suitable for no damage subcutaneous trace medication use.
The result of this study provide experimental basis for the transducing sheet joinning in the construction about the practical development of transdermal drug delivery device of laser shock wave.
Keywords laser shock wave (laser pressure waves, optical mechanical wave), plasma, laser transducer film, Mechanical effects
目 录
1 引言 2
1.1 激光冲击波技术 2
1.2 激光冲击波技术在加工领域中的应用 2
1.2.1 激光冲击成形技术 2
1.2.2 激光冲击强化技术 3
1.2.3 激光喷丸成形技术 3
1.3.1 基因转染 4
1.3.2 微射流给药 5
1.4 本文研究工作 6
2 激光等离子体冲击波理论 7
2.1 激光等离子体冲击波的形成 7
2.1.1 激光等离子体 7
2.1.2 激光等离子体冲击波 9
2.2 激光等离子体冲击波大小的影响因素 10
2.3 激光等离子体屏蔽现象以及产生机制 12
2.3.1 激光等离子体屏蔽现象 12
2.3.2 激光等离子体屏蔽机制 13
2.4 本章小结 14
3 激光换能片的冲击力检测 15
3.2.1 激光能量变化对激光换能片冲击力的影响 18
3.2.2 不同离焦度下能量变化时峰值电压的变化 24
3.3 本章小结 28
结 论 29
致 谢 31
参 考 文 献 32
1 引言
1.1 激光冲击波技术
早期人们就发现高功率激光打在靶材表面会产生冲击波，这样可以使靶材表面的一些特性发生改变。为了获得更大的冲击波压力，人们对原方法进行了改进[1]。先在靶材表面覆上一层吸收层，再在吸收层表面覆上一层约束层。当高功率激光作用于材料表面时，吸收层吸收激光能量，产生汽化，最后蒸汽电离，形成等离子体层。等离子体迅速向外膨胀，由于约束层的限制作用，使等离子体向下压力骤然升高，产生向靶材方向传播的冲击波，从而使靶材发生形变。