Journal of Mathematical Chemistry最新文献_第4页

A very efficient and sophisticated fourteenth-order phase-fitting method for addressing chemical issues 解决化学问题的高效、复杂的十四阶相位拟合方法

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-07-03 DOI: 10.1007/s10910-024-01636-2

Marina A. Medvedeva, T. E. Simos

引用次数: 0

A comparative study of cubic UAT and cubic UAH tension B-splines DQM for convection-diffusion equation: a statistical validation 对流扩散方程中立方 UAT 和立方 UAH 张力 B 样条 DQM 的比较研究：统计验证

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-07-01 DOI: 10.1007/s10910-024-01641-5

Manpreet Kaur, Mamta Kapoor

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Steady spectra of supreme resolution and lowest noise in high-order optimized derivative fast Fourier transform for ovarian NMR spectroscopy 用于卵巢核磁共振波谱的高阶优化导数快速傅立叶变换具有最高分辨率和最低噪声的稳定光谱

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-28 DOI: 10.1007/s10910-024-01643-3

Dževad Belkić, Karen Belkić

{"title":"Steady spectra of supreme resolution and lowest noise in high-order optimized derivative fast Fourier transform for ovarian NMR spectroscopy","authors":"Dževad Belkić, Karen Belkić","doi":"10.1007/s10910-024-01643-3","DOIUrl":"10.1007/s10910-024-01643-3","url":null,"abstract":"<div><p>The optimized derivative fast Fourier transform (dFFT) simultaneously increases resolution and reduces noise in spectra reconstructed from encoded time signals. The pertinent applications have recently been published for time signals encoded with and without water suppression by in vitro and in vivo magnetic resonance spectroscopy (MRS). Even with the employed lower derivative orders, genuine resonances were narrowed, their intensities enhanced and the background baselines flattened. This unequivocally separated many overlapped peaks that are the thorniest problem in data analysis by signal processing. However, it has been common knowledge that higher-order derivative spectra quickly deteriorate with the increased derivative order. The optimized dFFT can challenge such findings. An unprecedented resilience of this processor to derivative-induced distortions is presently demonstrated for high derivative orders (up to 20). The salient illustrations are given for the water residual, lactate quartet and lactate doublet alongside their close surroundings. These applications of diagnostic relevance for patients with cancer are reported for time signals encoded with water suppression by in vitro proton MRS of human ovary.</p></div>","PeriodicalId":648,"journal":{"name":"Journal of Mathematical Chemistry","volume":"62 8","pages":"2056 - 2080"},"PeriodicalIF":1.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10910-024-01643-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141506923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the Raleigh–Ritz variational method. Non-orthogonal basis set 关于 Raleigh-Ritz 变分法。非正交基集

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-28 DOI: 10.1007/s10910-024-01644-2

Francisco M. Fernández

引用次数: 0

A fourth-order compact ADI scheme for solving a two-dimensional time-fractional reaction-subdiffusion equation 求解二维时间分数反应-次扩散方程的四阶紧凑 ADI 方案

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-25 DOI: 10.1007/s10910-024-01638-0

Pradip Roul, Vikas Rohil

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Convergence analysis of optimal iterative family for multiple roots and its applications 多根最优迭代族的收敛性分析及其应用

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-24 DOI: 10.1007/s10910-024-01640-6

Bhavna, Saurabh Bhatia

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Graph realization of sets of integers 整数集合的图形实现

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-24 DOI: 10.1007/s10910-024-01642-4

Piotr Wawrzyniak, Piotr Formanowicz

{"title":"Graph realization of sets of integers","authors":"Piotr Wawrzyniak, Piotr Formanowicz","doi":"10.1007/s10910-024-01642-4","DOIUrl":"10.1007/s10910-024-01642-4","url":null,"abstract":"<div><p>Graph theory is used in many areas of chemical sciences, especially in molecular chemistry. It is particularly useful in the structural analysis of chemical compounds and in modeling chemical reactions. One of its applications concerns determining the structural formula of a chemical compound. This can be modeled as a variant of the well-known graph realization problem. In the classical version of the problem, a sequence of natural numbers is given, and the question is whether there exists a graph in which the vertices have degrees equal to the given numbers. In the variant considered in this paper, instead of a sequence of natural numbers, a sequence of sets of natural numbers is given, and the question is whether there exists a multigraph such that each of its vertices has a degree equal to a number from one of the sets. This variant of the graph realization problem matches the nature of the problem of determining the structural formula of a chemical compound better than other variants considered in the literature. We propose a polynomial time exact algorithm solving this variant of the problem.</p></div>","PeriodicalId":648,"journal":{"name":"Journal of Mathematical Chemistry","volume":"62 8","pages":"1965 - 1981"},"PeriodicalIF":1.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10910-024-01642-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A parameter-uniform hybrid scheme designed for multi-point boundary value problems that are perturbed 为受扰动的多点边界值问题设计的参数统一混合方案

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-24 DOI: 10.1007/s10910-024-01639-z

Parvin Kumari, Devendra Kumar, Jesus Vigo-Aguiar

{"title":"A parameter-uniform hybrid scheme designed for multi-point boundary value problems that are perturbed","authors":"Parvin Kumari, Devendra Kumar, Jesus Vigo-Aguiar","doi":"10.1007/s10910-024-01639-z","DOIUrl":"10.1007/s10910-024-01639-z","url":null,"abstract":"<div><p>The numerical solution of a class of second-order singularly perturbed three-point boundary value problems (BVPs) in 1D is achieved using a uniformly convergent, stable, and efficient difference method on a piecewise-uniform mesh. The presence of a boundary layer(s) on one (or both) of the interval’s endpoints is caused by the presence of the tiny parameter in the highest order derivative. As the perturbation parameter approaches 0, traditional numerical techniques on the uniform mesh become insufficient, resulting in poor accuracy and large blows without the use of an excessive number of points. Specially customised techniques, such as fitted operator methods or methods linked to adapted or fitted meshes that solve essential characteristics such as boundary and/or inner layers, are necessary to overcome this drawback. We developed a fitted-mesh technique in this paper that works for all perturbation parameter values. The monotone hybrid technique, which includes midway upwinding in the outer area and centre differencing in the layer region on a fitted-mesh condensing in the border layer region, is the basis for our difference scheme. In a discrete <span>(L^infty )</span> norm, uniform error estimates are constructed, and the technique is demonstrated to be parameter-uniform convergent of order two (up to a logarithmic factor). To show the effectiveness of the recommended technique and to corroborate the theoretical findings, a numerical example is presented. In practise, the convergence obtained matches the theoretical expectations.</p></div>","PeriodicalId":648,"journal":{"name":"Journal of Mathematical Chemistry","volume":"62 8","pages":"1982 - 2006"},"PeriodicalIF":1.7,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Linearized Boltzmann collision operator for a mixture of monatomic and polyatomic chemically reacting species 单原子和多原子化学反应混合物的线性化玻尔兹曼碰撞算子

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-19 DOI: 10.1007/s10910-024-01633-5

Niclas Bernhoff

{"title":"Linearized Boltzmann collision operator for a mixture of monatomic and polyatomic chemically reacting species","authors":"Niclas Bernhoff","doi":"10.1007/s10910-024-01633-5","DOIUrl":"10.1007/s10910-024-01633-5","url":null,"abstract":"<div><p>At higher altitudes near space shuttles moving at hypersonic speed the air is excited to high temperatures. Then not only mechanical collisions are affecting the gas flow, but also chemical reactions have an impact on such hypersonic flows. In this work we insert chemical reactions, in form of dissociations and associations, in a model for a mixture of mono- and polyatomic (non-reacting) species. More general chemical reactions, e.g., bimolecular ones, can be obtained by instant combinations of the considered reactions. Polyatomicity is here modelled by a continuous internal energy variable and the evolution of the gas is described by a Boltzmann equation. In the Chapman-Enskog process—and related half-space problems—the linearized Boltzmann collision operator plays a central role. Here we extend some important properties of the linearized operator to the considered model with chemical reactions. A compactness result, that the linearized operator can be decomposed into a sum of a positive multiplication operator—the collision frequency—and a compact integral operator, is obtained. The terms of the integral operator are shown to be (at least) uniform limits of Hilbert-Schmidt integral operators and, thereby, compact operators. Self-adjointness of the linearized operator follows as a direct consequence. Also, bounds on—including coercivity of—the collision frequency is obtained for hard sphere, as well as hard potentials with cutoff, like models. As consequence, Fredholmness as well as the domain of the linearized operator are obtained.</p></div>","PeriodicalId":648,"journal":{"name":"Journal of Mathematical Chemistry","volume":"62 8","pages":"1935 - 1964"},"PeriodicalIF":1.7,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10910-024-01633-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141506925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical investigation of two fractional operators for time fractional delay differential equation 时间分数延迟微分方程两个分数算子的数值研究

IF 1.7 3区化学

Journal of Mathematical Chemistry Pub Date : 2024-06-19 DOI: 10.1007/s10910-024-01637-1

Reetika Chawla, Devendra Kumar, Dumitru Baleanu

引用次数: 0