共查询到20条相似文献,搜索用时 78 毫秒
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尼龙66(PA66)与尼龙6(PA6)结构相似、性能更优,而尼龙6熔点低、价格廉,个别厂家在追求低成本时将尼龙6掺混在尼龙66中使用难以分辨。利用红外光谱衰减全反射法分析了不同PA66/6共混物的红外光谱图差别。根据PA66/6不同共混物的红外光谱图在930~935cm-1峰位的位移变化,拟合出了半定量分析公式。对未知尼龙样品进行了红外光谱分析,确定了未知样品的组份。 相似文献
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氰氟虫腙是一种新型的缩氨基脲类杀虫剂。利用核磁共振氢谱(~1 H NMR)、氢-氢相关谱(~1 H-1 H COSY)、核磁共振碳谱(~(13) C NMR)、氟谱(~(19)F NMR)、DEPT谱、异核单量子相关谱(HSQC)、异核多键相关谱(HMBC)对氰氟虫腙进行了解析,对其所有的NMR谱信号进行了归属。通过氢谱、碳谱、氟谱以及二维谱技术对该化合物进行了完整的结构分析,为氰氟虫腙的质量研究提供较为全面的参考依据。 相似文献
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为了使广大用户能更好地应用NMR波谱仪,开展研究工作,本文介绍我所修复浙江大学分析测试中心PMX60SI NMR波谱仪的情况,供参考。这台谱仪主要问题是:(1)磁场严重衰退,衰退率为3%,把所有磁分路退至外端.在波谱仪上找不到NRM信号。(2)基本磁场分辨率极差,降低3.5倍。(3)谱仪信噪比很低;处于无法运行的状态。针对上述问题,我们采取了以下措施:(1)首先使磁体与谱仪脱离,取出探头和旋转、匀场系统,去掉保温外套。利用测场仪寻找NMR信号,在相应1.3660T场强处找到NMR信号,而出厂场强为1.4092T。(2)对磁体进行充磁,并利用测场仪寻找60MHz NMR信号。 相似文献
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一、引言近15年来,核磁共振(NMR)仪由于更高场强超导体的出现和电子计算机的成功应用,在仪器的功能和在物理、化学、生物学等领域里的应用方面,取得了许多惊人的进展。譬如固体高分辨 NMR,多核种测量,以及 NMR 成象技术在医学中的应用等。但是尽管这些成就为NMR 的应用开辟了新的前景,然而高分辨 NMR 相似文献
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针对系统模型不确定性、未知输入扰动,为对干扰解耦以及不依赖系统未知输入扰动分布阵先验信息,提出了系统干扰分布阵未知的GPS/SINS(global positioning system/strapdown interial navigation system)故障诊断算法.设计了MEP-UIO(model error prediction-unknow input observer)故障诊断观测器,改进了传统未知输入故障诊断观测器(UIO)假设系统未知扰动分布阵已知的不足;利用凸二次规划最优化原理,构造了关于未知扰动分布阵的目标函数,提出了满足目标函数最小的未知输入扰动分布阵的最优估计算法以及状态估计误差方差最小的故障诊断系统增益阵设计方法.仿真结果表明,提出的MEP-UIO故障诊断观测器设计算法相比传统Kalman滤波精度更高,验证了该故障诊断算法的有效性. 相似文献
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报道了FPS节能减摩剂、二硫代磷酸钼(MoDTP)和二硫代磷酸锌(ZnDTP)的~(31)P—NMR谱,并用~(31)P—NMR法研究了其组分的构成和变化。结果表明,FPS节能减摩剂是由31.0%有机Mo—S化合物、53.8%有机Zn—S化合物、3.5%有机P=S化合物和11.7%有机P=O化合物组成的有机磷混合物。 相似文献
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新型黃原酸衍生物的合成及其摩擦学性能 总被引:2,自引:1,他引:1
采用不同烷基的黄原酸钠盐与氯亚甲基苯并咪唑进行取代反应,合成了3种新化合物,产物结构经IR、UV、1H NMR、13C NMR、MS和元素分析进行了表征确证,考察了其油溶性和热稳定性,并利用四球试验机考察了合成的3种新化合物在液体石蜡中的摩擦学性能。结果表明,合成的3种化合物均能溶于大部分有机溶剂而难溶于水;3种化合物表现出很好的热稳定性,其第一分解温度均高于178℃,最高到480℃才分解完全,能适应一般工况条件的要求。3种新化合物在液体石蜡中有很好的极压抗磨作用。 相似文献
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Conventional nuclear magnetic resonance (NMR) instruments are limited by their large volume volume. A miniature NMR spectrometer is reported using a partially enclosed miniature permanent magnet and a low-cost solenoid microcoil probe. The miniature NMR spectrometer uses a sample volume smaller than conventional NMR spectrometers by a factor of 1000. Transverse relaxation times were obtained by the miniature spectrometer using 150?nL of 40?mM copper sulfate, 1?M aqueous sucrose, absolute ethanol, and deionized water. The results demonstrate that high signal-to-noise ratios were obtained. The results were also compared with a commercial NMR spectrometer and suitable accuracy of the laboratory-constructed device was obtained. The miniature NMR spectrometer was employed for the characterization of heated soybean oil. The reported miniature NMR spectrometer is anticipated to have applications for onsite detection. 相似文献
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Hashimoto S Noda Y Maekawa H Takamura H Fujito T Moriya J Ikeda T 《The Review of scientific instruments》2010,81(10):104101
A NMR system for in situ analysis of hydrogen storage materials under high pressure and temperature conditions was developed. The system consists of a gas pressure and flow rate controlling unit, a temperature controller, a high temperature NMR probe tunable for both (1)H and other nuclei, and a sample tube holder. Sample temperature can be controlled up to 623 K by heated N(2) gas flow. Sample tube atmosphere can be substituted by either H(2) or Ar and can be pressurized up to 1 MPa under constant flow rate up to 100 ml/min. During the NMR measurement, the pressure can be adjusted easily by just handle a back pressure valve. On the blank NMR measurement, (1)H background noise was confirmed to be very low. (1)H and (11)B NMR spectrum of LiBH(4) were successfully observed at high temperature for the demonstration of the system. The intensity of the (1)H NMR spectra of H(2) gas was also confirmed to be proportional to the applied pressure. 相似文献
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有机固体研究是一门新兴的多学科交叉的材料科学,本文介绍了固体高分辨核磁共振技术在有机固体研究中的常用的有效的实验方法,概述了近年来国外用固体核磁共振技术在有机固体的结构研究、分子复合物研究、化学动力学研究及晶型研究等方面的部分研究成果。 相似文献
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A widely used method to determine base oil aromaticity was introduced by G. Brandes in 1956 and is based on a correlation between the infrared aromatic absorption band at 1610 cm−1 and the aromaticity determined by the n-d-M method. Accurate and absolute aromaticities can be measured by carbon-13 NMR but, infortunately, this technique is not suitable for routine analysis. The aromaticities measured by NMR are almost invariably significantly lower than those obtained by Brandes' method. In this study, the areas of the infrared aromatic bands at 1610 and 815 cm−1 of over 70 base oils with aromaticities ranging from 1–16% were correlated by multilinear regression with their carbon-13 NMR aromaticities. An equation to calculate the aromaticity from infrared absorptions was derived. These aromaticities show an excellent match with carbon-13 NMR data. This new infrared method can be applied as a fast and convenient base-oil quality control tool. 相似文献
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