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p-Trimethylammonium chloridobenzyloxycarbonyl chloride (5a) was synthesized from p-dimethylaminobenzaldehyde (1) and its amides, such as aniline, p-bromoaniline, p-acetamidoaniline, glycine, glycine methyl, glycine ethyl, glycine benzyl esters and L-leucine methyl ester were prepared. Their hydrogenolytic behaviors were examined. Two dipeptides, glycyl glycine and glycyl L-leucine, were synthesized with the title protecting group via azides in aqueous solution. 相似文献
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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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We investigate the temperature dependence of radiation-induced attenuation (RIA) at 1 310 nm for a Ge/P co-doped fiber after a steady-state γ-ray irradiation.A γ irradiation facility 60Co source is used to irradiate the fiber at a dose rate of 0.5 Gy/min,satisfying a total dose of 100 Gy.The test temperature ranges from-40 to 60℃ by 20℃,and the RIA of the fiber is obtained using a power measuring device.The experimental result demonstrates that RIA exhibits a steady,monotonic,and remarkable temperature dependence after approximately 48h of accelerated annealing at 70℃.The optical fiber irradiated with a high dose and annealed sufficiently can be used as a temperature sensor. 相似文献
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污染气体红外光谱特征的快速提取与识别 总被引:1,自引:1,他引:0
利用小波变换的多尺度分析对污染气体红外光谱数据进行处理,并使用神经网络对红外光谱数据进行分类识别。实验结果表明:小波变换与神经网络的有机结合,有利于污染气体红外光谱的快速特征提取和识别, 并具有较高的识别率,是一个有效的识别系统。 相似文献
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Effect of radiation-induced mean wavelength shift in optical fibers on the scale factor of an 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 trans- mission wavelength in optical fiber and the scale factor of interferometric fiber optic gyroscopes (IFOGs), three types of polarization-maintaining (PM) fibers are tested by using a 60 Co γ-radiation source. The observed different mean wave- length shift (MWS) behaviors for different fibers are interpreted by color-center theory involving dose rate-dependent absorption bands in ultraviolet and visible ranges and total dose-dependent near-infrared absorption bands. To evaluate the mean wavelength variation in a fiber coil and the induced scale factor change for space-borne IFOGs under low radiation doses in a 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 transmission in fibers will shift to a shorter wavelength in a 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 IFOGs. 相似文献
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2011年11月29日,我们敬爱的导师张滂院士与世长辞。噩耗传来,作为学生的我们悲痛万分。师恩难忘,谨以此文作为对先生的纪念,并表达我们对先生的感谢与怀念之情。张滂先生早年就读于西南联大,毕业后曾作为老一辈有机化学家吴学周先生的助手开展研究工作。1945年留学英国,先后就读于利兹大学和剑桥大学,1949年7月获得有机化学博士学位。据了解,张滂先生是第一位获得剑桥大学博士学位的中国人。张先生于新中国成立之际回国效力,投身于祖国的教育和科技事业,先后任教于燕京大学和北京大学。 相似文献
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病床是医院的关键医疗资源,其管理水平关系到医疗资源能否合理配置.因此,如何优化病床资源并高效利用医院病床资源是一个具有挑战性的课题.对国内外学者在病床资源优化利用方面的研究进行梳理和评价,分析目前病床资源调度的研究动态以及发展前景,从而提出四点病床资源优化的研究展望.这不仅为国内外学者在未来病床资源调度的研究方向上提供指导性建议,而且对我国医院管理者合理、有效地利用现有病床资源具有重要的现实意义. 相似文献