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气体反压化学发泡注塑产品泡孔结构形成与演变过程的实验研究
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作者 李帅 徐一涵 +4 位作者 孙雪梅 麻晓飞 孙成通 卢世伟 李洋 《山东科学》 CAS 2020年第2期33-39,共7页
以标准拉伸样条为研究对象,系统探讨了气体反压工艺中反压压力和作用时间对化学发泡注塑成型过程中熔体发泡行为的影响。根据实验获得的结果,提出了前沿泡孔不破裂的临界反压压力、熔体不发泡的临界反压压力和二次发泡卸压时间,并揭示... 以标准拉伸样条为研究对象,系统探讨了气体反压工艺中反压压力和作用时间对化学发泡注塑成型过程中熔体发泡行为的影响。根据实验获得的结果,提出了前沿泡孔不破裂的临界反压压力、熔体不发泡的临界反压压力和二次发泡卸压时间,并揭示了气体反压技术对化学发泡注塑过程中熔体发泡行为的影响机理。 展开更多
关键词 发泡注塑 气体反压技术 发泡行为 发泡机理
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Research Progress of Optical H2O Sensor With a DFB Diode Laser 被引量:2
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作者 Guangping LV Jun CHANG Qingpu WANG Qiang WANG Wei WEI 《Photonic Sensors》 SCIE EI CAS 2014年第2期113-119,共7页
In the field of near infrared H2O sensing, the acquisition of the absorption signal usually is from a noisy background, thus it is important to adopt an effective signal demodulation method. This study introduced the ... In the field of near infrared H2O sensing, the acquisition of the absorption signal usually is from a noisy background, thus it is important to adopt an effective signal demodulation method. This study introduced the research progress in the field of trace water vapor detection, covering different individual gas detection techniques. On the basis of the conventional double-beam differential absorption, the division method in voltage and the dual-peak method based on the differential value of two adjacent absorption lines have been studied. Voltage division has an excellent stability to temperature variation, mechanical extrusion, and fiber bend loss. The dual-peak method proved a linear relation with the water vapor concentration, and this method provided a way to measure the concentration at high pressure. Furthermore, the so called balanced ratiometer detection (BRD) was introduced. It has an outstanding self-adjusting capability, and it can also avoid an excess phase difference caused by the current-to-voltage converting circuit, thus this method has a high sensitivity. In addition, the second harmonic technique applied to gas detection was introduced, and for the high-frequency modulation via driving current, l/f was suppressed apparently; as a result, this technique realized a better sensitive detection by one to two orders of magnitude. 展开更多
关键词 Water vapor gas sensing DFB diode laser absorption spectrum
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