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Xiangdong Liu Hongwei Liu Kexu Yuan Huiping Du 《International Journal of Infrared and Millimeter Waves》1991,12(9):1023-1034
According to the angular-spectrum method, a radiation beam of an antenna horn in the Fresnal region is decomposed into the plane waves with the fast Fourier transform algorithm and the waves diffracted from a reflection grating are superposed as a diffracted beam. Compared with the reflected beam from the same size mirror, the radiation half width of the diffracted beam from a grating is narrower and its lateral shape is shift. These performances have been experimentally verified at Ka-band by: (1). The relative diffraction efficiencies in the first order with two triangular gratings which is put along propagating direction of a beam produced by a conical lens-horn. (2). H-plane lateral width with power—3dB lapsed of the focus beam from a grating and a mirror in a grating spectrometer for millimeter waves (25–100 GHz). 相似文献
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Hongwei Liu Xiangdong Liu KeXue Yuan KeSong Hu Yutau Chen 《International Journal of Infrared and Millimeter Waves》1993,14(8):1693-1699
A five-channel grating spectrometer for use in millimeter wave band (25100GHz) is described with its design theory of optical path, and measured results of insertion loss and resolving power. 相似文献
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Detection limits and reduced mobilities for 12 ribonucleotides and 4 ribonucleosides were measured by ambient pressure electrospray ionization-ion mobility spectrometry (ESI-IMS). With the instrument used in this study it was possible to separate some of these compounds within mixtures. Detection limits reported for ribonucleotides and ribonucleosides ranged from 15 to 300 pmol and the reduced mobilities ranged from 41 to 56 suggesting that ambient pressure ESI-IMS may be used for their rapid and sensitive separation and detection. This report demonstrates that it was possible to use ion mobility spectrometry (IMS) to obtain a spectrum for the separation of nucleotides and nucleosides in less than 1 min. The application holds great promise for nucleotide analysis in the area of separating DNA fragments in genome sequencing and also for forensics DNA typing examinations used for the identification of blood stains in crime scenes and paternity testing. 相似文献
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Let and be graphs where the set of vertices is the set of points of the integer lattice and the set of edges consists of all pairs of vertices whose city block and chessboard distances, respectively, are 1.In this paper it is shown that the partition dimensions of these graphs are 3 and 4, respectively, while their metric dimensions are not finite. Also, for every n3 there exists an induced subgraph of of order 3n-1 with metric dimension n and partition dimension 3. These examples will answer a question raised by Chartrand, Salehi and Zhang. Furthermore, graphs of order n9 having partition dimension n-2 are characterized, thus completing the characterization of graphs of order n having partition dimension 2, n, or n-1 given by Chartrand, Salehi and Zhang. The list of these graphs includes 23 members. 相似文献
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计算机模拟研究目标转换因子分析分辨重迭溶出伏安峰 总被引:2,自引:0,他引:2
本文用计算机模拟研究目标转换因子分析分辨重迭溶出伏安峰.设计了两个计算机程序(SPGRELEP)和(ELECTTFA)用于伏安图模拟和目标转换因子分析,采用了伏安图全部信息和矩阵处理技术.ELECTTFA程序用于确定组分数,验证组分种类和进行未知重迭溶出伏安图的定量分析.实验结果表明本方法是成功的,甚至对严重重迭溶出伏安图亦可奏效. 相似文献
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Tabrizchi M 《Talanta》2004,62(1):65-70
The separation efficiency of ion mobility spectrometry (IMS) may be measured in terms of either resolving power, based on a single-peak definition, or peak-to-peak resolution, based on the separation of pairs of adjacent peaks. Usually resolving power decreases with temperature. However, the experimental results show that the peak-to-peak resolution may be increased in some cases. Negative ion mobility spectra of halide ions are better resolved at elevated temperatures. In addition, the peaks corresponding to protonated monomer of amylacetate and the proton-bound dimer of ethylacetate are well separated at 100 °C while they fully overlap at 18 °C. This paper focuses on the effect of temperature on peak-to-peak resolution. It was also observed that in some cases peak-to-peak resolution decreases with temperature. Examples are the spectra of cyclohexanone and methyl-iso-butyl ketone (MIBK) as well as dimethyl methyl phosphonate (DMMP) and MIBK. The increase or decrease in resolution at elevated temperatures has been attributed to the changes in separation factor (α) which is governed by the different hydration and clustering tendency of ions. 相似文献