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61.
利用群论和对称性分析的方法研究了具有D3d对称性构型的B2H6分子的声子态及其声子间耦合等问题。研究发现,B2H6存在5种不同的声子态,它们分别具有D3d群下的a1g、a1u、a2u、eg与eu对称性,其中a2u与eu具有红外活性,a1g和eg具有拉曼活性,而a1u是非活性的;在B2H6的声子态中只有eg是活跃的声子态;活跃声子态eg与eg之间的耦合作用将会产生耦合声子态a1g和eg;B2H6分子的电声耦合作用一定会导致B2H6分子发生杨-泰勒畸变,畸变致使B2H6分子从D3d对称性降低到C2h对称性。 相似文献
62.
蚕豆是世界上第六大食用豆类作物,具有较高的营养价值和药用价值。蚕豆常见的颜色有白色和绿色,两者在口感上稍有区别,在经济价值上也不同,利用傅里叶变换红外光谱对同一产地同一年份的两种颜色的蚕豆进行光谱研究。结果表明,两种颜色的蚕豆在子叶的吸收峰上有区别。根据红外光谱的谱峰形状和位置,可以判断两种蚕豆的主要化学成分。利用该方法可以快速、简捷地区分两种蚕豆。 相似文献
63.
熊杰 《黄冈师范学院学报》2014,(3):47-49
以C8051f020单片机作为控制核心,采用热释电红外传感器模块DYP-ME003作为前端探测器,通过SPI协议模式对语音芯片ISD1700进行语音录放功能的精确操控,实现语音门铃录音、播放,报警声录音、播放等。若有人入侵,则通过单片机控制GSM模块按照设置好的号码及信息发送到主人的手机上,达到报警目的。测试结果表明,该系统能真实再现语音效果,运行稳定、可靠。 相似文献
64.
Light-induced color changes and chemical modification of treated and untreated chestnut wood surface
AbstractThe aim of this work is to study the surface modifications of chestnut (Castanea sativa Mill.) wood by reflectance spectrophotometry and Fourier transform infrared spectroscopy (FTIR) in order to understand the mechanisms that cause changes and to suggest possible solutions to avoid degradation phenomena. The experimental data were statistically treated to evaluate their significance. Concerning the surface protection of wood, starting from the results obtained by testing different commercial products, attention was focused on a novel organic preservative/consolidant product (Linfoil®) that has attracted great interest in the field of conservation of wooden artifacts. Color monitoring showed that wood surface color undergoes an important variation due to photoirradiation, occurring within the first 24 hours and mainly due to L* decrease and b* increase. Though the protective treatment modifies wood color, nevertheless the product tested seems to protect the wood surface by reducing photoyellowing. FTIR analysis indicated that irradiation caused the degradation of lignin and increased the concentration of the chromophore groups on the wood surface. Changes in the chromaticity coordinates can be linked to the degradation of lignin and to increase of the concentration of carbonyl groups. 相似文献
65.
以环戊基甲基酮和水合肼为原料,合成一种新的酮连氮化合物(环戊基甲基酮连氮,C14N2H24),采用1H NMR、13C NMR和IR表征确认产物的结构,并通过Gaussian 09计算对产物分子构型进行解析,表明(1E,2E)为最稳定构型;同时测定环戊基甲基酮连氮在常压下的基本物理化学性质,包括沸点(Tb,238.4℃... 相似文献
66.
丁卓 《华南师范大学学报(社会科学版)》2020,(4):144-155
科幻文学的近未来设定,是指通过当下意识辩证地预构未来的社会结构体系。许多科幻作品明确设定了近未来。日本当代科幻文学在延续其科幻传统的基础上直面社会危机,从政治批判、灾难预测、时空探索和文化反思四个向度设定近未来,并生成标志性符号,形成对现实与未来关系的创造性理解,体现了在“智能+”时代文学文化观念与时俱进的特质。对近未来的设定表明,日本当代科幻文学将人置于时空、科技和文化网络的核心,创作出既有普适意义又有日本民族特色的科幻文学,对我们认识和发展中国科幻文学有较强的借鉴价值。 相似文献
67.
Microfibril angle (MFA) – the orientation of cellulose fibres in the S2 layer of the secondary cell wall – is a key determinant of the stiffness and strength of timber. The microfibril angle depends on the way in which the timber was grown and its position within the tree. Microfibril angle can be measured by X-ray diffraction and other methods, but the methods in current use are slow or require advanced instrumentation. The aim of this study was to explore the use of polarised Fourier transform infrared (FTIR) microscopy as a relatively fast and inexpensive method for measuring MFA in historic Scots pine (Pinus sylvestris L.). The FTIR measurements were calibrated against X-ray measurements of MFA in modern Scots pine. We observed a wide range in MFA values and a radial pattern of MFA similar to modern Scots pine in undecayed Scots pine heartwood from sixteenth and seventeenth century beams in Scottish secular buildings. The density of the heartwood was also similar to modern plantation-grown Scots pine despite the much slower growth rate recorded in the ring widths of the historic timber. The sapwood, which had been attacked by both insect pests and fungi, showed an erratic reduction in density and a large increase in MFA compared to the modern material. The increased sapwood MFA was attributed to selective destruction of the S2 layer of the wood cell walls by fungal decay. Using MFA measurements in conjunction with density offers the possibility to estimate the mechanical properties of sound historic pine timber, to detect fungal decay more sensitively than by density alone, and to distinguish between pest and fungal attack in a way that relates directly to the remaining mechanical performance of the timber. 相似文献
68.
光电探测系统的设计原理及应用 总被引:2,自引:0,他引:2
该文根据“非典”时期红外测温仪的应用,讨论了光电系统的设计思想和基本原理及应用。 相似文献
69.
以三聚氯氰为起始原料合成了四种三嗪衍生物,并用红外光谱和质谱分析法对它们进行了表征.产品检测结果表明,四种三嗪衍生物有较高熔点,在常温下不易挥发. 相似文献
70.