There might appear some technology problems of green laser pointer

And the operation power meter of green laser pointer is easy
Say top pressure side, the so-called Huocongtianxiang roof top of a sudden to drop under heavy loads accident, this is to test the body strength, and come back to look at the circumstances of the crash test, and general impact as long as there is a door open even if qualified, basically Ashkenazi four doors of the car can be full body strength reassuring, whether it is a top pressure or roll-over has a very important role! The Japanese car the GOA energy absorption body then probably we should a lot less. There is talk about an experience I do not know have the same sense, driving a high speed in many of Japan's car has a body floating feeling (unless it is more expensive), while the German car, even a very low-end products have not yet this feeling.
Even the Passat and Audi have ah, first of all, as long as the car must have a problem, we are just as much as possible to affect us less, and consequences of the lighter! Accord knocked interrupt the speed below 80 km and a hit that is broken, Audi knocked the speed is nearly 200 km, but also the folder tree circling a week off, the difference is nothing less than the poor ah! German cars have airbags unexploded, but it is low impact unexploded; over 100 kilometers of the Camry hit the airbag does not burst, the question of the who? All day attack Jetta and Santana meaningful? That was the previous generations of models, how can you win? And how your crown outperformed 30 years ago, the Ferrari? There might appear some technology problems of  green laser pointer .
Focal plane at the top of the of the workpiece being away from the focus, and vice versa for negative defocus. In accordance with the theory of geometrical optics, when the positive and negative defocus amount equal to the corresponding power density is approximately the same plane, but the weld pool shape actually. Negative defocus, the availability of greater penetration, which is related with the formation of the molten pool. The experiments show that the laser heating 50 to 200μs material begins to melt, the formation of liquid metal and partial vaporization of high-pressure steam, and at very high speed jet, and a dazzling white. At the same time, high concentrations of vapor liquid metal movement to the weld pool edge, the formation of depression in the weld pool center. When negative defocus, the power density of material internal surface area is also high, easy to form a stronger melting, vaporization, so that the light pass deeper into the material.