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Effect of radiation-induced mean wavelength shift in optical fibers on the scale factor of interferometric fiber optic gyroscope at a wavelength of 1300 nm 下载免费PDF全文
In order to analyze the effect of wavelength-dependent radiation-induced attenuation (RIA) on the mean transmission wavelength in optical fiber and the scale factor of interferometric fiber optic gyroscopes (IFOGs), three types of polarization-maintaining (PM) fibers is tested by using a 60Co γ -radiation source. The observed different mean wavelength shift (MWS) behaviors for different fibers are interpreted by color-center theory involving dose rate-dependent absorption bands in ultraviolet and visible range and total dose-dependent near infrared absorption bands. To evaluate the mean wavelength variation in fiber coil and the induced scale factor change for space-borne IFOG under low radiation dose in space environment, the influence of dose rate on the mean wavelength is investigated by testing four germanium (Ge) doped fibers and two germanium-phosphorus (Ge-P) codoped fibers irradiated at different dose rates. Experimental results indicate that the Ge-doped fibers show the least mean wavelength shift during irradiation and their mean wavelength of optical signal transmitting in fibers will shift to shorter wavelength in low-dose-rate radiation environment. Finally, the change in the scale factor of IFOG resulting from the mean wavelength shift is estimated and tested, and it is found that the significant radiation-induced scale factor variation must be considered during the design of space-borne IFOG. 相似文献
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针对织物疵点检测,将灰度共生矩阵(Gray-level Co-occurrence Matrix,GLCM)与反向投影结合起来,提出了一种基于GLCM的反向投影方法(GLCM-BP)。首先介绍了GLCM-BP的原理,然后给出了织物疵点检测流程,分析并优化了GLCM的距离d与灰度级N等参数,选择了相应的滤波与自适应阈值分割方法以检测疵点,同时给出了7种常见疵点的检测结果。最后将本文方法与GLCM方法作了检出率的比较。结果表明,提出的方法具有良好的疵点分割效果,可显著提高疵点检出率。 相似文献
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一般线性模型只能拟合一些特殊的资料,而广义线性模型则不一样,它具有较大的灵活性,运用也日趋广泛.基于此,运用广义估计方程证明了高维变量下Poisson分布相关阵的相合性. 相似文献
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为了研究煤尘爆炸气固态残留物成分差异性及其时空分布规律,利用水平管道煤尘爆炸装置进行了煤尘爆炸实验,收集并分析了气固态残留物类别及特征。研究表明:爆炸后煤尘中灰分显著增加,挥发分和固定碳减少;爆炸前后煤尘的微观形貌特征差别明显,爆炸后煤尘颗粒表面光滑,且产生了颗粒破裂现象,部分颗粒中出现孔洞,少数颗粒呈现薄壳状,颗粒之间出现了粘结现象;煤尘爆炸气体残留物成分主要有氧气、氮气、一氧化碳、二氧化碳、甲烷、乙烯、乙烷、乙炔、丙烷等,爆源点处最低氧气浓度仅为2.52%,一氧化碳浓度达到0.38%~0.68%,距离爆源点越远,氧气浓度越高,碳氧化物气体与烃类气体浓度越低。 相似文献
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