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1.
溶液自由基ESR谱的计算机模拟   总被引:1,自引:1,他引:0  
根据溶液自由基电子自旋共振(ESR)原理,用高级BASIC语言编写了溶液自由基谱的模拟程序。自由基的ESR能级用一级近似求解,谱线的线型采用洛仑兹和高斯型的混合线型函数,程序规定体系中核自旋量子数可从1/2到7/2,不等性核的数目最多可达10组,每组中等性核的数目原则上不受限制。通过二萘嵌苯阳离子自由基和硝基苯负离子自由基谱模拟二个例子加以说明,模拟结果是满意的。  相似文献   

2.
小型13C NMR谱图数据库   总被引:1,自引:0,他引:1  
本文着重介绍用当前微机系统上流行的DBASEⅡ建立谱图数据库以及用BASIC语言进行结构检索的方法。检索系统能方便地提供用户收集、修正、查询、显示和打印谱图数据和分子结构图的功能。这种系统对建立专用的小型谱图数据库有实用价值。  相似文献   

3.
李晶鑫  童伟 《波谱学杂志》2023,40(1):100-110
EasySpin是一款较为流行的电子顺磁共振(EPR)谱图模拟和拟合软件,LabVIEW是一种图形化编程语言开发环境.本文介绍了一款使用LabVIEW为EasySpin设计的图形用户界面LV-EasySpin.LV-EasySpin提供了一种直观的操作方法来实现连续波EPR多组分波谱的可视化模拟和拟合.本文辅以各种模式下的实例进行说明,阐述了LV-EasySpin的设计思路与实现方案,最终希望具有简洁、易操作界面的LV-EasySpin可以降低用户使用EasySpin分析EPR谱图的难度.  相似文献   

4.
新开发的双自由基(TN3)由全取代三苯甲基自由基(trityl)和氮氧自由基两部分组成.TN3的室温EPR谱图由4条不对称的宽谱线组成,具有典型的双自由基特征.以抗坏血酸作为模型化合物发现该双自由基能用来同时检测体系的氧化还原态和氧气浓度.  相似文献   

5.
机载相机在上升过程中,由于温度降低和镜头各部分材料的导热率大小不同,镜头部分会产生温度梯度,从而导致非球面光学系统产生梯度折射率.利用有限元分析软件对镜头部分进行瞬态热分析以模拟机载相机上升过程中温度的变化情况,将有限元分析不同时间节点温度分布结果导入编写的折射率梯度系数拟合程序,将所求解的梯度折射率系数通过镜面类型接口在光学软件中建立光学系统模型,利用点列图的弥散斑半径评价不同时间节点梯度折射率对成像质量的影响.结果表明,机载相机刚升入工作高度时温度梯度最大,对成像质量影响也最严重,梯度折射率系数随着温度梯度系数的降低而降低,同时成像质量提高,该结果对光学系统的设计具有指导意义.  相似文献   

6.
中子厚针孔成像数值模拟研究   总被引:3,自引:0,他引:3       下载免费PDF全文
陈法新  郑坚  杨建伦 《物理学报》2006,55(11):5947-5952
为了解决成像的针孔设计问题,基于蒙特卡罗方法建立了一套模拟中子针孔成像过程的程序,并且通过编写的图像显示程序可以直观地观察到记录介质所成的二维图像,同时可以对图像的某些参数进行判读. 关键词: ICF 蒙特卡罗 半影成像 点扩散函数  相似文献   

7.
化合物SADTLER标准13C图谱编号检索系统   总被引:2,自引:0,他引:2  
本文介绍一个建立了包括常用检索和智能检索SADTLER标准13C图谱系统,其中还具有设定谱峰数峰和谱化学位移误差之功能。系统中的程序用高级BASIC语言编写并由编译BASIC变为机器语言。系统运行于16位的IBM-PC兼容微机。  相似文献   

8.
单通道GPS模拟信号源是基于软件无线电技术的,通过构建基于DSP+DDS技术的单通道GPS模拟信号源的系统模型(图1),对算法进行设计、推导,采用Matlab软件对系统仿真,用C语言编写该系统的算法程序和接口程序,最终完成系统的软、硬件设计与调试。  相似文献   

9.
活性氧和氮自由基(ROS/RNS)在一系列的人类疾病中扮演着双重角色.它们可以是氧化剂,诱导氧化状态,导致组织损伤.它们又可以是信号传导因子,诱发保护性反应,使得被调节的组织器官经受得起更强的损伤.鉴于它们在生物医学中的重要作用,检测它们产生和分布的技术的研究因而变得必要和紧迫.在体电子自旋共振(EPR)波谱和成像技术渐已被应用于活体生物体系中用以表针和显像ROS/RNS.EPR波谱特性(包括线宽、强度和寿命)以及空间分布信息已为动物甚至人体病理模型中氧化还原状态和氧分布的检测提供不可缺少的依据.该文将简单描述和讨论一系列在体EPR波谱和成像技术在器官和组织中的应用,其中包括活体组织氧化还原状态,活体组织氧分布和时间演化,自由基空间以及谱-空间成像等.  相似文献   

10.
对掺Cr~(3 )乙酰丙酮铝单晶的(001),(100)和(110)晶面进行晶面旋转EPR扫描,得到共振磁场随旋转角度变化的实验图形,根据本征插方法编写的程序,对实验谱图进行投合,得到下述顺磁参数,D=0.5870±O.005cm~(-1),E=-0.00490±0.0001cm~(-1),g~2=g_y=1.965土0.001,g_r=1.984±0.001.  相似文献   

11.
Continuous wave electron paramagnetic resonance imaging (EPRI) of living biological systems requires rapid acquisition and visualization of free radical images. In the commonly used multiple-stage back-projection image reconstruction algorithm, the EPR image cannot be reconstructed until a complete set of projections is collected. If the data acquisition is incomplete, the previously acquired incomplete data set is no longer useful. In this work, a 3-dimensional progressive EPRI technique was implemented based on inverse Radon transform in which a 3-dimensional EPR image is acquired and reconstructed gradually from low resolution to high resolution. An adaptive data acquisition strategy is proposed to determine the significance of projections and acquire them in an order from the most significant to the least significant. The image acquisition can be terminated at any time if further collection of projections does not improve the image resolution distinctly, providing flexibility to trade image quality with imaging time. The progressive imaging technique was validated using computer simulations as well as imaging experiments. The adaptive acquisition uses 50-70% less projections as compared to the regular acquisition. In conclusion, adaptive data acquisition with progressive image reconstruction should be very useful for the accelerated acquisition and visualization of free radical distribution.  相似文献   

12.
In this paper, we propose a novel approach for electron paramagnetic resonance (EPR) mixture spectra analysis based on blind source separation (BSS) technique. EPR spectrum of a free radical is often superimposed by overlapping spectra of other species. It is important and challenging to accurately identify and quantify the 'pure' spectra from such mixtures. In this study, an automated BSS method implementing independent component analysis is used to extract the components from mixed EPR spectra that contain overlapping components of different paramagnetic centers. To apply this method, there is no requirement to know the component spectra or the number of components in advance. The method is applied to analyze free radical EPR spectra which are collected from standard chemical system, cultured cell suspense, and ex vivo rat kidneys by spin trapping EPR technique. Results show that the BSS method proposed here is capable of identifying the component EPR spectra from mixtures with unknown compositions. The BSS technique can offer powerful aids in resolving spectral overlapping problems in general EPR spectroscopy analysis.  相似文献   

13.
糖与氨基酸反应涉及一种新的自由基的生成。这种自由基EPR谱特征的超精细结构是由一组两个等性的氮核、三组等性的质子所贡献。谱的超精细特征和谱线分裂的数目主要取决于氨基酸的结构。从13C NMR谱和反应过程的分析,我们提出如下设想:这种新自由基产物应该是1,2-4,5四取代的哌嗪双自由基。用实验中测得的波谱参数在ASPECT-2000型计算机上进行了EPR谱的模拟,模拟的理论谱与实验谱很好地重合,进一步支持了上述的设想。本文还提出了反应中自由基形成的可能机理。  相似文献   

14.
Petroleum of Arabian and Colombian origin was studied by electron paramagnetic resonance (EPR) spectroscopy at X- (9 GHz), Q- (34 GHz) and W-bands (94 GHz). The experiments were performed at room temperature (about 300 K) and at 77 K (W-band only). The asymmetry in the lines corresponding to free radicals was observed more intensely in the W-band spectra. The values of the line width ΔH in the spectra increased linearly with the microwave frequency utilized in the EPR experiments. A mathematical simulation of the free radical signal for the EPR spectra in three bands with a set of parameters corresponding to a single species was attempted, but this was not exactly coincident with the experimental signals, suggesting that the hyperfine interaction of the unpaired electron with its neighborhood corresponds to more than one species of radical in the molecular structure of the petroleum asphaltene.  相似文献   

15.
将ER-200D ESR波谱仪ASPECT 3000计算机采集的ESR图谱传输到IBM PC/XT计算机上,通过自行设计的ESR图谱模拟程序ESRSIMU,同屏显示比较,方便、灵活地对多自由基体系溶液ESR一级近似谱进行了模拟,获取了各个自由基的ESR波谱参数和体系中各类自由基的相对浓度等信息.对单个自由基ESR谱的模拟,ESRSIMU的运行速度比BRUKER EPR 3002快近100倍.  相似文献   

16.
《Radiation measurements》2009,44(2):144-148
A software was developed on the base of non-linear simulation, which allowed the deconvolution of EPR spectra of tooth enamel into three components: native, radiation- and mechanically induced. The software was designed for the reconstruction of individual absorbed doses by EPR spectra of tooth enamel using the method of additive irradiation of samples. It has been demonstrated with the help of this program that the presence of mechanically induced paramagnetic centers in enamel samples led to an excessive individual absorbed dose reconstructed by EPR spectra of tooth enamel.  相似文献   

17.
Free radicals play important roles in many physiological and pathological pathways in biological systems. These free radicals can be detected and quantified by their EPR spectra. The measured EPR spectra are often mixtures of pure spectra of several different free radicals and other chemicals. Blind source separation can be applied to estimate the pure spectra of interested free radicals. However, since the pure EPR spectra are often not independent of each other, the approach based on independent component analysis (ICA) cannot accurately extract the required spectra. In this paper, a novel sparse component analysis method for blind source separation, which exploits the sparsity of the EPR spectra, is presented to reliably extract the pure source spectra from their mixtures with high accuracy. This method has been applied to the analysis of EPR spectra of superoxide, hydroxyl, and nitric oxide free radicals, for both simulated data and real world ex vivo experiment. Compared to the traditional self-modeling method and our previous ICA-based blind source separation method, the proposed sparse component analysis approach gives much better results and can give perfect separation for mixtures of superoxide spectrum and hydroxyl spectrum in the ideal noise-free case. This method can also be used in other similar applications of quantitative spectroscopy analysis.  相似文献   

18.
The gamma-irradiated single crystals of 2-Bromo-4′-methoxyaceto-phenone (2B4MA) were investigated using electron paramagnetic resonance (EPR) technique. Density-functional theory calculations were employed to investigate and identify the radicals that have been assumed to be formed upon irradiation of 2B4MA single crystals. The EPR spectra of 2B4MA were recorded at different orientations in the magnetic field at room temperature. Taking into account the chemical structure and experimental spectra of irradiated single crystal of 2B4MA, it was assumed that at least two different radicals were produced in the sample. Following this assumption, six possible radicals were modeled and EPR parameters were calculated by using the DFT, B3LYP/6-311+G(d), for the modeled radicals individually. The calculated hyperfine coupling constants and g-tensors were used as initial values for simulation studies. The three crystallographic axes on the simulated spectra were well matched with experimental spectra for the two modeled radicals. Thus, we identified the R1 type radical and R4 type radical as paramagnetic species produced in gamma-irradiated 2B4MA.  相似文献   

19.
The needles of spruce and other conifers were investigated by using EPR spectroscopy. Contrary to previous studies, examples of weakened and diseased spruces exhibiting strong manganese(II) signals were found. This situation was found for trees damaged by acid rains in south-west Poland. For weakened spruces and pines from other regions the manganese(II) signal of decreased intensity and free radical signals were observed. Such trees also exhibited iron(III) signal, which appears to, be another indicator of reduced vitality. The influence of harmful agents on living plant parts was investigated on the basis of free radical EPR spectra.  相似文献   

20.
A stochastic Liouville equation (SLE) was numerically solved to obtain pulsed Fourier-transform (FT) EPR spectra on a radical pair system created in a photo-induced chemical reaction. Numerical calculations were applied to the photo-chemical reaction of deuterated acetone and 2-propanol at low temperatures. In this reaction system, the antiphase structures of the EPR signals, so called spin-correlated radical pair (SCRP) signals of two identical isopropyl ketyl radicals and spin-polarized free isopropyl ketyl radicals were observed by FT-EPR and continuous wave time-resolved (CW TR) EPR techniques. In the present work, FT-EPR spectra of the antiphase structure signals of the radical pair themselves as well as spin-polarized free radical signals were simulated. Additionally, rising behavior of free radical signals polarized by the radical pair mechanism (RPM) was also clarified. Furthermore two-dimensional (2D) FT-EPR nutation spectra were simulated in the both cases with and without the radical pairs by the use of SLE. In these simulations, strong DC components in the nutation frequency dimension, were well reproduced as was obtained in experiments. It was shown that relaxation during the microwave pulse was essential for the appearance of the DC components.  相似文献   

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