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1.
梅二文  顾文芳 《分析化学》1995,23(5):594-603
本文对阿达玛变换光谱和成象的原理进行了简单介绍,并对80年代以来阿达玛变换技术在分析化学中的应用进行了评述。  相似文献   

2.
通过程序升温脱附程序升温表面反应及脉冲反应等化学物理技术,综合分析研究了铁系无铬型CO高温变换催化剂的吸附性能及化学反应特性。研究表明,NBC-1型催化剂对H2O具有很强的吸附能力,不易吸附CO及CO2,该催化剂上水煤气变换反应的机理为氧化-还原反应机理。  相似文献   

3.
小波变换及其在色谱重叠峰解析中的应用   总被引:3,自引:0,他引:3  
本文介绍了小波分析的基本原理、计算方法及其在色谱重叠峰解析中的应用。显示了小波分析的特点,表明了小波分析用于重叠峰的解析与传统的方法相比具有其优越性。  相似文献   

4.
小波变换及其在化学中的应用   总被引:6,自引:0,他引:6  
介绍了傅里叶变换、加窗傅里叶变换和小波变换的基本概念,以及小波变换在化学中的应用。  相似文献   

5.
 采用微型等温积分反应器,在3 MPa,598~728 K以及气体组成(摩尔分率)为CO 0.066~0.139,CO2 0.041~0.1,H2 0.262~0.457,H2O 0.217~0.386和N2 0.077~0.271的条件下,对国产LB型低汽气比中温变换催化剂的动力学特性进行了系统的研究. 对基于一级反应模式、二级反应模式和幂函数经验式的三种变换反应动力学模型,以Simplex-Gauss-Newton复合法估计了相应的模型参数. 数理统计检验结果表明,三种动力学模型在统计学意义上均是可信的. 进一步的工业应用检验表明,由于结构上的不同,当用于非等温工业反应器性能分析时,三种模型预报的结果具有明显差异,相比之下,幂函数型动力学方程更适宜于描述LB型变换催化剂的动力学特性. 因此,由等温实验数据和传统的数理统计检验获得的动力学模型具有不确定性,为使动力学模型的应用更为可靠,对所建立的动力学模型进行工业应用检验是必要的.  相似文献   

6.
铁系无铬型CO高温变换催化剂的谱学研究   总被引:11,自引:0,他引:11  
用Mossbauer谱,XRD及TEM技术对铁系无铬型催化剂的前驱态、母体及还原态在不同工艺条件下的生成及晶相结构的微变过程进行了研究。确证了水合四氧化三铁Fe3-xO4·nH2O和γ-Fe2O3晶态的形成,并探讨了晶相参数微变引起晶体结构的差异导致的催化活性的变化。在Fe3-xO4·nH2O中SB/SA比值为2,x值接近于0时催化活性最高。  相似文献   

7.
电分析化学中的化学计量学方法及其应用进展   总被引:1,自引:0,他引:1  
本文综述了电分析化学领域中化学计量学方法的应用进展,引用文献65篇。  相似文献   

8.
通过程序升温脱附(TPD)、程序升温表面反应(TPSR)及脉冲反应(PSR)等化学物理技术,综合分析研究了铁系无铬(NBC-1)型CO高温变换催化剂的吸附性能及化学反应特性。研究表明,NBC-1型催化剂对H2O具有很强的吸附能力,不易吸附CO及CO2,该催化剂上水煤气变换反应的机理为氧化-还原(redox)反应机理  相似文献   

9.
卢小泉 《分析化学》2007,35(2):292-292
小波变换的概念是由法国从事石油信号处理的工程师J.Morlet在1974年首先提出的并建立了反演公式。它解决了Fourier变换不能解决的许多困难问题,所以被誉为“数学显微镜”,具有分析发展史上里程碑式的意义。本书是分析科学现代方法丛书中的一册,是国内第一本介绍小波分析在分析化学中应用的图书。作者卢小泉教授自1994年始从事小波分析在分析化学中的应用研究,他在自己科研的基础上参阅了国内外大量的有关小波分析的文献后编著此书,书中内容具有很强的针对性和实用性。该书的出版能给分析化学工作者,特别是化学计量学工作者提供一些有价值的参考。  相似文献   

10.
铈对铁系无铬变换催化剂还原的影响   总被引:1,自引:1,他引:0  
以XRD,TPR,SEM,XPS为手段了含Ce铁系无铬变换催化剂的还原过程,在氧化态样品中,Ce有细化颗粒的作用,在还原过程中,Ce有表面富集现象,从而使初始还原温度降低而还原结束的温度升高。  相似文献   

11.
Fullerene polyhedra of icosahedral symmetry have the midpoints of their 12 pentagonal faces at the vertices of a macroicosahedron and can be characterized by the patterns of their hexagonal faces on the (triangular) macrofaces of this macroicosahedron. The numbers of the vertices in fullerene polyhedra of icosahedral symmetry satisfy the Goldberg equation v=20(h 2+hk+k 2), where h and k are two integers and 0 <hk≥ 0 and define a two-dimensional Goldberg vector G = (h, k). The known tripling (leapfrog), quadrupling (chamfering), and septupling (capra) transformations correspond to the Goldberg vectors (1, 1), (2, 0), and (2, 1), respectively. The tripling and quadrupling transformations applied to the regular dodecahedron generate achiral fullerene polyhedra with the full I h point group. However, the septupling transformation destroys the reflection operations of the underlying icosahedron to generate chiral fullerene polyhedra having only the I icosahedral rotational point group. Generalization of the quadrupling transformation leads to the fundamental homologous series of achiral fullerene polyhedra having 20 n 2 vertices and Goldberg vectors (n, 0). A related homologous series of likewise achiral fullerene polyhedra having 60 n 2 vertices and Goldberg vectors (n, n) is obtained by applying the tripling transformation to regular dodecahedral C20 to give truncated icosahedral C60 followed by the generalized operations (as in the case of quadrupling) for obtaining homologous series of fullerenes. Generalization of the septupling (capra) transformation leads to a homologous series of chiral C20m fullerenes with the I point group and Goldberg vectors G=(h, 1) where m=h 2+h+1.  相似文献   

12.
TMA/DTMA with DTA studies on the thermal changes of kaolinite were performed with special emphasis on the crystallization behaviour of amorphous SiO2. The results of four different physical techniques (semiquantitative XRD, DTA, TMA and DTMA) were clearly in good agreement with the fact that the 1420°C exotherm in DTA is due to silica crystallization.Thanks to Dr. B. K. Sarkor, Director of the Institute for his kind permission to publish the paper and to Mr. D. K. Ahosh for his needful suggestions.  相似文献   

13.
The negative impacts on the ecosystem of antibiotic residues in the environment have become a global concern. However, little is known about the transformation mechanism of antibiotics by manganese peroxidase (MnP) from microorganisms. This work investigated the transformation characteristics, the antibacterial activity of byproducts, and the degradation mechanism of tetracycline (TC) by purified MnP from Phanerochaete chrysosporium. The results show that nitrogen-limited and high level of Mn2+ medium could obtain favorable MnP activity and inhibit the expression of lignin peroxidase by Phanerochaete chrysosporium. The purified MnP could transform 80% tetracycline in 3 h, and the threshold of reaction activator (H2O2) was about 0.045 mmol L−1. After the 3rd cyclic run, the transformation rate was almost identical at the low initial concentration of TC (77.05–88.47%), while it decreased when the initial concentration was higher (49.36–60.00%). The antimicrobial potency of the TC transformation products by MnP decreased throughout reaction time. We identified seven possible degradation products and then proposed a potential TC transformation pathway, which included demethylation, oxidation of the dimethyl amino, decarbonylation, hydroxylation, and oxidative dehydrogenation. These findings provide a novel comprehension of the role of MnP on the fate of antibiotics in nature and may develop a potential technology for tetracycline removal.  相似文献   

14.
The reaction of the heterometallic vinylidene cluster RuCo2(CO)9(3-2-C=CHPh) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) proceeds readily in the presence of Me3NO to furnish the new cluster RuCo2(CO)7(bpcd)(3-2-C=CHPh) as the sole product. This cluster has been isolated by preparative chromatography and characterized in solution by IR spectroscopy. The molecular structure was determined by X-ray diffraction analysis, which has confirmed the chelation of the bpcd ligand to the ruthenium center and the change in the coordination mode exhibited by the vinylidene ligand. RuCo2(CO)7(bpcd)(3-2-C=CHPh) crystallizes in the triclinic space group P , a = 10.5788(9), b = 11.909(1), c = 19.526(2) Å, = 84.491(9)°, = 78.068(8)°, = 63.760(7)°, V = 2158.7(4) Å3, Z = 2, and d calc = 1.581.  相似文献   

15.
以乙二胺为模板剂(SDA)合成微孔晶体磷酸钴, 可以得到多种不同的结构. 本文在合成四种不同结构类型的微孔磷酸钴(命名为CoPO-en-1, CoPO-en-2, CoPO-en-3, CoPO-en-4, en 为乙二胺的英文缩写)过程中发现, 它们之间不仅可以在水热合成条件下相互转化, 在焙烧处理条件下也能实现转化. 研究发现, 在水热合成过程中, CoPO-en-2、CoPO-en-4 分别是CoPO-en-1、CoPO-en-3 的晶化中间物, 在较低晶化温度下或者较高温度的晶化初期, 可以发现它们的身影. 一旦晶化温度升高或者晶化时间延长, 它们就分别转化为CoPO-en-1和CoPO-en-3. 在合成产物的热处理过程中发现: CoPO-en-2、CoPO-en-3、CoPO-en-4 都能够通过焙烧转化为CoPO-en-1. 这种现象表明, 几种微孔磷酸钴结构间的稳定性存在递变关系.  相似文献   

16.
The controlled self‐assembly of CuI and an asymmetric ligand with mixed N/S donors, 2‐(tert‐butylthio)‐N‐(pyridin‐3‐yl)acetamide ( L ), afforded three CuI coordination polymers (CPs), [Cu4I4 L 2(MeCN)2]n ( 1 ), [Cu4I4 L 2]n ( 2 ), and {[Cu4I4 L 2] ? MeOH}n ( 3 ). X‐ray analyses showed that CPs 1 – 3 are supramolecular isomers with 1, 2, and 3D structures, respectively. CP 1 adopts a stairstep Cu4I4 cluster, whereas CPs 2 and 3 are composed of cubane‐like Cu4I4 clusters. Crystal‐to‐crystal transformations of 1 to 2 and 3 showed reversible transformations between different Cu4I4 clusters using heat or solvent (acetonitrile or methanol) vapor. CP 2 was reversibly transformed to 3 by the addition of methanol and heat. Therefore, the transformations between supramolecular isomers 1 , 2 , and 3 are completely reversible.  相似文献   

17.
选择一种高硫新西兰煤(NXL)作为研究对象,高纯Ar气氛中,以5℃/min的升温速率在管式炉中热解,热解终温为300~1 000℃。用XPS研究煤及不同温度下半焦中氮、硫的赋存形态。将N 1s谱图用Lorentzian-Gaussian拟合分为四个峰:N-6(398.8±0.4)eV、N-5(400.2±0.3)eV、N-Q(401.4±0.3)eV和N-X(402.9±0.5)eV;S 2p谱图分为六个峰:硫铁矿(162.5±0.3)eV、硫化物(163.3±0. 4)eV、噻吩(164.1±0.2)eV、亚砜(166.0±0.5)eV、砜(168.0±0.5)eV和硫酸盐硫(169.5±0.5)eV。结果表明,煤中氮元素的主要存在形式是吡啶、吡咯、质子化吡啶和氮氧化物;低于600℃,半焦中的氮元素主要以吡啶和吡咯形式存在;随温度的升高,吡咯向吡啶转化;当温度超过900℃,氮氧化物这一形态消失。该煤中的硫以有机硫为主,其中,噻吩硫占50%以上;随着热解温度的升高,煤中的硫铁矿硫逐步转化为无机硫化物,600℃时分解完全。  相似文献   

18.
The eigenfunctions and energies of general dilated Hamiltonians are expanded in powers of the dilatation parameter. These expansions, augmented by stationarity and stability conditions, are used to derive exact sum rules for bound and resonance states. Particular attention is paid to Hamiltonians with potentials which depend on external parameters, such as the nuclear coordinates in molecules, and to self-consistent potentials. The sum rules can be employed in practical computations to improve the quality of the results and may also serve in analyzing the results from approximate calculations.  相似文献   

19.
Summary An algorithm for the parallelization of the atomic to molecular integral transformation and the subsequent steps in a GUGA based MCSCF calculation is presented. Timing data shows that the transformation and diagonalization steps are well parallelized and that several of the other portions of the MCSCF code are moderately parallel. Remaining sequential bottlenecks are identified.  相似文献   

20.
The development of a temperature control system based on semiconductor thermobatteries has been used in a set of devices for studying the martensitic transformation. The devices range from a simple stage for an optical microscope to a more elaborated system as a differential scanning calorimeter [1]. Here the attention is placed in this last system. The general problems of the temperature scanning calorimetry are reviewed from the signal theory point of view and the solutions applied to our system discussed. Some measurements are shown as an example of its application.  相似文献   

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