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A Spectral Convolutional Neural Network Model Based on Adaptive Fick’s Law for Hyperspectral Image Classification
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作者 Tsu-Yang Wu Haonan Li +1 位作者 Saru Kumari Chien-Ming Chen 《Computers, Materials & Continua》 SCIE EI 2024年第4期19-46,共28页
Hyperspectral image classification stands as a pivotal task within the field of remote sensing,yet achieving highprecision classification remains a significant challenge.In response to this challenge,a Spectral Convol... Hyperspectral image classification stands as a pivotal task within the field of remote sensing,yet achieving highprecision classification remains a significant challenge.In response to this challenge,a Spectral Convolutional Neural Network model based on Adaptive Fick’s Law Algorithm(AFLA-SCNN)is proposed.The Adaptive Fick’s Law Algorithm(AFLA)constitutes a novel metaheuristic algorithm introduced herein,encompassing three new strategies:Adaptive weight factor,Gaussian mutation,and probability update policy.With adaptive weight factor,the algorithmcan adjust theweights according to the change in the number of iterations to improve the performance of the algorithm.Gaussianmutation helps the algorithm avoid falling into local optimal solutions and improves the searchability of the algorithm.The probability update strategy helps to improve the exploitability and adaptability of the algorithm.Within the AFLA-SCNN model,AFLA is employed to optimize two hyperparameters in the SCNN model,namely,“numEpochs”and“miniBatchSize”,to attain their optimal values.AFLA’s performance is initially validated across 28 functions in 10D,30D,and 50D for CEC2013 and 29 functions in 10D,30D,and 50D for CEC2017.Experimental results indicate AFLA’s marked performance superiority over nine other prominent optimization algorithms.Subsequently,the AFLA-SCNN model was compared with the Spectral Convolutional Neural Network model based on Fick’s Law Algorithm(FLA-SCNN),Spectral Convolutional Neural Network model based on Harris Hawks Optimization(HHO-SCNN),Spectral Convolutional Neural Network model based onDifferential Evolution(DE-SCNN),SpectralConvolutionalNeuralNetwork(SCNN)model,and SupportVector Machines(SVM)model using the Indian Pines dataset and PaviaUniversity dataset.The experimental results show that the AFLA-SCNN model outperforms other models in terms of Accuracy,Precision,Recall,and F1-score on Indian Pines and Pavia University.Among them,the Accuracy of the AFLA-SCNN model on Indian Pines reached 99.875%,and the Accuracy on PaviaUniversity reached 98.022%.In conclusion,our proposed AFLA-SCNN model is deemed to significantly enhance the precision of hyperspectral image classification. 展开更多
关键词 Adaptive ficks law algorithm spectral convolutional neural network metaheuristic algorithm intelligent optimization algorithm hyperspectral image classification
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Chloride Diffusivity Analysis of Existing Concrete Based on Fick's Second Law
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作者 张俊芝 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第1期142-146,共5页
According to the existing concrete core samples obtained in site, chloride concentration and porosity of existing normal hydraulic concrete were measured, and chloride diffusivity in existing hydraulic concrete was st... According to the existing concrete core samples obtained in site, chloride concentration and porosity of existing normal hydraulic concrete were measured, and chloride diffusivity in existing hydraulic concrete was studied. By Fick’s second law, the chloride diffusion coefficients in the steady diffusion area were calculated. The chloride diffusion of different mix proportion concrete was tested, and chloride diffusion coefficients and porosities of freshly concrete were measured, moreover, the relationship between diffusion coefficient and porosity was analyzed. The results show that the varying law of chloride diffusion coefficient with exposure time of existing concrete can be predicted in a better way by Fick’s second law and water-cement ratios or porosity of concrete and chloride concentration in existing concrete. 展开更多
关键词 existing concrete ficks second diffusion law CHLORIDE diffusion coefficient
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Casson hybrid nanofluid flow over a Riga plate for drug deliveryapplications with double diffusion
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作者 Abeer S.Alnahdi Taza Gul 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期311-320,共10页
Casson fluid-mediated hybrid nanofluids are more effective at transferring heat than traditional heat transfer fluids in terms of thermal conductivity.Heat exchangers,cooling systems and other thermal management syste... Casson fluid-mediated hybrid nanofluids are more effective at transferring heat than traditional heat transfer fluids in terms of thermal conductivity.Heat exchangers,cooling systems and other thermal management systems are ideal for use with Casson fluids.Precise control of the flow and release of medication is necessary when using Casson fluids in drug delivery systems because of their unique rheological properties.Nanotechnology involves the creation of nanoparticles that are loaded with drugs and distributed in Casson fluid-based carriers for targeted delivery.In this study,to create a hybrid nanofluid,both single-walled carbon nanotubes(SWCNTs)and multi-walled carbon nanotubes(MWCNTs)are dispersed in a Casson fluid with Fourier’s and Fick’s laws assumptions.The Casson fluid is suitable for various engineering and medical applications due to the enhancement of heat transfer and thermal conductivity by the carbon nanotubes.Our objective is to understand how SWCNTs and MWCNTs impact the flow field by studying the flow behavior of the Casson hybrid nanofluid when it is stretched against a Riga plate.The Darcy-Forchheimer model is also used to account for the impact of the porous medium near the stretching plate.Both linear and quadratic drag terms are taken into account in this model to accurately predict the flow behavior of the nanofluid.In addition,the homotopy analysis method is utilized to address the model problem.The outcomes are discussed and deliberated based on drug delivery applications.These findings shed valuable light on the flow characteristics of a Casson hybrid nanofluid comprising SWCNTs and MWCNTs.It is observed that the incorporation of carbon nanotubes makes the nanofluid a promising candidate for medical applications due to its improved heat transfer properties. 展开更多
关键词 carbon nanotubes(CNTs) Riga plate Casson fluid with Fourier’s and ficks laws analytical solutions
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Origin, Alternative Expressions of Newcomb-Benford Law and Deviations of Digit Frequencies
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作者 Gene Whyman 《Applied Mathematics》 2021年第7期576-586,共11页
The Newcomb-Benford law, which describes the uneven distribution of the frequencies of digits in data sets, is by its nature probabilistic. Therefore, the main goal of this work was to derive formulas for the permissi... The Newcomb-Benford law, which describes the uneven distribution of the frequencies of digits in data sets, is by its nature probabilistic. Therefore, the main goal of this work was to derive formulas for the permissible deviations of the above frequencies (confidence intervals). For this, a previously developed method was used, which represents an alternative to the traditional approach. The alternative formula expressing the Newcomb-Benford law is re-derived. As shown in general form, it is numerically equivalent to the original Benford formula. The obtained formulas for confidence intervals for Benford’s law are shown to be useful for checking arrays of numerical data. Consequences for numeral systems with different bases are analyzed. The alternative expression for the frequencies of digits at the second decimal place is deduced together with the corresponding deviation intervals. In general, in this approach, all the presented results are a consequence of the positionality property of digital systems such as decimal, binary, etc. 展开更多
关键词 Benford’s law Confidence Intervals in Benford’s law Alternative Expression of Benford’s law Benford’s law for Different Numeral systems Frequencies of Digits at the second Decimal Place
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New Interpretation of Newton’s Law of Universal Gravitation
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作者 Dalgerti L. Milanese 《Journal of High Energy Physics, Gravitation and Cosmology》 2017年第4期600-623,共24页
Elliptical motions of orbital bodies are treated here using Fourier series, Fortescue sequence components and Clarke’s instantaneous space vectors, quantities largely employed on electrical power systems analyses. Us... Elliptical motions of orbital bodies are treated here using Fourier series, Fortescue sequence components and Clarke’s instantaneous space vectors, quantities largely employed on electrical power systems analyses. Using this methodology, which evidences the analogy between orbital systems and autonomous second-order electrical systems, a new theory is presented in this article, in which it is demonstrated that Newton’s gravitational fields can also be treated as a composition of Hook’s elastic type fields, using the superposition principle. In fact, there is an identity between the equations of both laws. Furthermore, an energy analysis is conducted, and new concepts of power are introduced, which can help a better understanding of the physical mechanism of these quantities on both mechanical and electrical systems. The author believes that, as a practical consequence, elastic type gravitational fields can be artificially produced with modern engineering technologies, leading to possible satellites navigation techniques, with less dependency of external sources of energy and, even, new forms of energy sources for general purposes. This reinterpretation of orbital mechanics may also be complementary to conventional study, with implications for other theories such as relativistic, quantum, string theory and others. 展开更多
关键词 ORBITAL MOTIONs Gravity Newton’s second law Hook’s Elastic Forces FOURIER Electrical Circuits TRANsFORMATIONs of Fortescue and Clarke Instantaneous space VECTORs Instantaneous Complex Power
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用Fick第二定律描述混凝土中氯离子浓度分布的适用性 被引量:16
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作者 刘芳 宋志刚 +1 位作者 潘仁泉 金伟良 《混凝土与水泥制品》 2005年第4期7-10,共4页
结合室内试验及现场试验所测得的氯离子浓度分布,与Fick第二定律给出的氯离子浓度分布曲线进行比较,分析了不同侵蚀环境下氯离子浓度分布的特点并计算了其与Fick分布两者间的相关性。结果表明,Fick第二定律适用于室内试验环境、现场盐... 结合室内试验及现场试验所测得的氯离子浓度分布,与Fick第二定律给出的氯离子浓度分布曲线进行比较,分析了不同侵蚀环境下氯离子浓度分布的特点并计算了其与Fick分布两者间的相关性。结果表明,Fick第二定律适用于室内试验环境、现场盐雾作用环境和海水浸泡环境,经适当修正后,还可适用于有碳化或硫酸根影响的环境,但不适用于海水反复淋溅作用下的环境。 展开更多
关键词 混凝土 耐久性 氯离子 fick第二定律 淋溅作用
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玄武岩纤维混凝土力学性能及氯盐侵蚀行为
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作者 季自刚 任效坤 +3 位作者 孙涛 黄绍宁 周益云 李福海 《混凝土》 CAS 北大核心 2024年第3期57-60,67,共5页
为探究氯盐侵蚀对玄武岩纤维混凝土力学性能的影响及氯盐在混凝土中的侵蚀行为,以抗压强度、劈裂抗拉强度、氯离子沉积量为表征手段进行盐雾侵蚀试验,并根据Fick第二定律计算得到不同侵蚀龄期下氯离子扩散系数。结果表明:混凝土强度在... 为探究氯盐侵蚀对玄武岩纤维混凝土力学性能的影响及氯盐在混凝土中的侵蚀行为,以抗压强度、劈裂抗拉强度、氯离子沉积量为表征手段进行盐雾侵蚀试验,并根据Fick第二定律计算得到不同侵蚀龄期下氯离子扩散系数。结果表明:混凝土强度在氯盐侵蚀过程中呈现先上升后下降的趋势;通过氯盐侵蚀的玄武岩纤维与普通混凝土相比,能有效提高混凝土的抗压及劈裂抗拉强度,降低混凝土劣化速率;在相同深度及侵蚀龄期下玄武岩纤维混凝土氯离子含量均低于普通混凝土;此外,氯离子扩散系数随着侵蚀龄期的增加而降低,且相同龄期下玄武岩纤维混凝土氯离子扩散系数均低于普通混凝土。 展开更多
关键词 玄武岩纤维 力学性能 氯离子含量 fick第二定律 氯离子扩散系数
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纸质玩具中BPA和BPS化合物的迁移 被引量:1
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作者 葛文亮 吴慧慧 +4 位作者 王领军 徐立伟 匡华 胥传来 刘丽强 《包装工程》 CAS 北大核心 2021年第23期84-91,共8页
目的研究纸质玩具中双酚A(BPA)和双酚S(BPS)经口暴露途径下的迁移规律,并考察BPA和BPS迁移的适用性。方法采用间接酶联免疫(IC-ELISA)检测方法和Fick第二定律研究不同温度(4,37,60℃)、盐浓度(0.001,0.01,0.1 mol/L)、pH(4,7,9)条件下... 目的研究纸质玩具中双酚A(BPA)和双酚S(BPS)经口暴露途径下的迁移规律,并考察BPA和BPS迁移的适用性。方法采用间接酶联免疫(IC-ELISA)检测方法和Fick第二定律研究不同温度(4,37,60℃)、盐浓度(0.001,0.01,0.1 mol/L)、pH(4,7,9)条件下双酚类物质经口暴露下的迁移规律,模拟纸质玩具中BPA和BPS的迁移过程。结果双酚类物质迁移量与温度和盐离子浓度呈正相关,且在酸性和碱性条件的模拟液中溶出增加,纸质玩具中BPA和BPS经口暴露途径下的迁移规律符合Fick第二定律。正常迁移模拟条件下(37℃、盐浓度0.01 mol/L、pH=7的唾液模拟液)测得BPA和BPS的迁移系数分别为1.3×10^(-17),6.6×10^(18)cm^(2)/s。结论基于酶免疫检测方法,构建了纸质玩具中BPA和BPS的迁移模型,并成功应用于预测纸质玩具中双酚类化合物的迁移情况,根据纸质玩具中双酚类物质的迁移模拟实验,计算双酚类物质在不同条件下的扩散系数,并拟合迁移模型,预测盲样中BPA和BPS的迁移情况,与实际迁移情况对比,结果表明理论预测值与实际迁移量基本一致,此项工作对于儿童纸质玩具中双酚类物质的风险性评估具有重要意义。 展开更多
关键词 双酚 IC-ELIsA fick第二定律 扩散系数 迁移模型
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Fick第二定律的应用研究现状与展望 被引量:10
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作者 胡玲 徐芸芸 吴瑾 《河北建筑科技学院学报》 2005年第3期50-53,共4页
Fick第二定律通常被用来描述氯离子在混凝土中的扩散性质,对于Fick第二定律在钢筋混凝土结构寿命预测的应用,已经有许多学者对其进行了研究。本文总结了他们的研究成果,分别从Fick第二定律公式中的各个影响参数出发,对公式进行讨论,并... Fick第二定律通常被用来描述氯离子在混凝土中的扩散性质,对于Fick第二定律在钢筋混凝土结构寿命预测的应用,已经有许多学者对其进行了研究。本文总结了他们的研究成果,分别从Fick第二定律公式中的各个影响参数出发,对公式进行讨论,并且根据公式中各个参数的不确定性,提出了Fick第二定律应用发展方向,即应用随机微分方程理论建立随机模型。 展开更多
关键词 fick第二定律 扩散系数 表面浓度 随机模型
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基于VTK的Fick第二定律动态扩散过程模拟 被引量:1
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作者 张建生 《计算机系统应用》 2012年第12期117-120,共4页
Fick第二定律是固体物理学中关于非稳态条件下的扩散宏观理论基础,动态扩散过程的可视化模拟将有助于研究人员直观快捷地了解和掌握物质扩散对周围物质和环境的影响.使用VTK实现了Fick第二定律在一维条件下动态扩散过程的可视化模拟,为... Fick第二定律是固体物理学中关于非稳态条件下的扩散宏观理论基础,动态扩散过程的可视化模拟将有助于研究人员直观快捷地了解和掌握物质扩散对周围物质和环境的影响.使用VTK实现了Fick第二定律在一维条件下动态扩散过程的可视化模拟,为研究人员应用Fick第二定律以及迅速地直观了解扩散结果提供了有益的参考和方法. 展开更多
关键词 fick第二定律 VTK 动态扩散 模拟
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海洋环境状态下受氯盐侵蚀钢筋混凝土结构耐久性寿命预测
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作者 周萌 张振浩 +1 位作者 黄雨杭 宁中伟 《工程建设》 2024年第7期16-21,共6页
在海洋环境中,Cl^(-)入侵造成的钢筋锈蚀是影响钢筋混凝土结构服役寿命的主要原因。因此,提出合理描述Cl^(-)入侵的耐久性模型对于准确预测港口混凝土结构服役寿命至关重要。文章运用MATLAB软件对Cl^(-)在钢筋混凝土结构中的扩展过程进... 在海洋环境中,Cl^(-)入侵造成的钢筋锈蚀是影响钢筋混凝土结构服役寿命的主要原因。因此,提出合理描述Cl^(-)入侵的耐久性模型对于准确预测港口混凝土结构服役寿命至关重要。文章运用MATLAB软件对Cl^(-)在钢筋混凝土结构中的扩展过程进行仿真模拟,将得到的数据进行Gamma过程建模,提出一种Cl^(-)侵蚀条件下钢筋混凝土耐久性寿命预测的新方法。根据菲克第二定律,得到混凝土的Cl^(-)扩散理论基准模型;同时,运用有限差分法和蒙特卡罗法得出多因素作用下结构钢筋表面Cl^(-)浓度数据和结构耐久性数据,做出直方图,与基于Gamma过程的耐久性寿命概率密度函数理论曲线进行对比分析,证明新方法的可行性。结果表明:理论曲线与直方图高度吻合,表明了基于Gamma过程的氯盐侵蚀环境下钢筋混凝土结构耐久性模型的准确性和可靠性。本文成果可为确保港口混凝土结构在预计服役期内满足适用性和安全性要求提供一定的借鉴与参考。 展开更多
关键词 钢筋混凝土结构 氯盐侵蚀 Gamma过程 寿命预测 菲克第二定律
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Exact Solution of Fractional Diffusion Model with Source Term used in Study of Concentration of Fission Product in Uranium Dioxide Particle 被引量:2
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作者 房超 曹建主 孙立风 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第5期863-867,共5页
The exact solution of fractional diffusion model with a location-independent source term used in the study of the concentration of fission product in spherical uranium dioxide (U02) particle is built. The adsorption... The exact solution of fractional diffusion model with a location-independent source term used in the study of the concentration of fission product in spherical uranium dioxide (U02) particle is built. The adsorption effect of the fission product on the surface of the U02 particle and the delayed decay effect are also considered. The solution is given in terms of Mittag-Leffler function with finite Hankel integral transformation and Laplace transformation. At last, the reduced forms of the solution under some special physical conditions, which is used in nuclear engineering, are obtained and corresponding remarks are given to provide significant exact results to the concentration analysis of nuclear fission products in nuclear reactor. 展开更多
关键词 fractional diffusion fick's law source term finite Hankel transformation Laplace transformation
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Radionuclides in primary coolant of a fluoride salt-cooled hightemperature reactor during normal operation 被引量:1
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作者 Guo-Qing Zhang Shuai Wang +5 位作者 Hai-Qing Zhang Xing-Wang Zhu Chao Peng Jun Cai Zhao-Zhong He Kun Chen 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第3期109-114,共6页
The release of fission products from coated particle fuel to primary coolant, as well as the activation of coolant and impurities, were analysed for a fluoride saltcooled high-temperature reactor(FHR) system, and the ... The release of fission products from coated particle fuel to primary coolant, as well as the activation of coolant and impurities, were analysed for a fluoride saltcooled high-temperature reactor(FHR) system, and the activity of radionuclides accumulated in the coolant during normal operation was calculated. The release rate(release fraction per unit time) of fission products was calculated with STACY code, which is modelled mainly based on the Fick's law, while the activation of coolant and impurities was calculated with SCALE code. The accumulation of radionuclides in the coolant has been calculated with a simplified model, which is generally a time integration considering the generation and decay of radionuclides. The results show that activation products are the dominant gamma source in the primary coolant system during normal operation of the FHR while fission products become the dominant source after shutdown. In operation condition,health-impacts related nuclides such as ~3H, and ^(14)C originate from the activation of lithium and coolant impurities including carbon, nitrogen, and oxygen. According to the calculated effective cross sections of neutron activation,~6Li and ^(14)N are the dominant ~3H production source and ^(14)C production source, respectively. Considering the high production rate,~3H and ^(14)C should be treated before being released to the environment. 展开更多
关键词 source TERM FHR PRIMARY COOLANT ficks law Diffusion
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基于Fick-小波包变换方法对土壤CO_2浓度时间序列的去噪处理 被引量:3
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作者 谢宝良 胡军国 +2 位作者 李烨斐 陈芳 毛国平 《传感技术学报》 CAS CSCD 北大核心 2019年第5期715-722,共8页
土壤CO_2浓度时间序列的数据质量易受到外界环境及土壤监测仪质量的影响,导致不能精确的测定土壤呼吸。针对土壤CO_2浓度时间序列的数据质量问题,本文提出小波包变换和Fick第二定律结合的方法对时间序列进行去噪分析。实验结果显示,无... 土壤CO_2浓度时间序列的数据质量易受到外界环境及土壤监测仪质量的影响,导致不能精确的测定土壤呼吸。针对土壤CO_2浓度时间序列的数据质量问题,本文提出小波包变换和Fick第二定律结合的方法对时间序列进行去噪分析。实验结果显示,无论从均值,信噪比,均方根误差和斜率距离来看,本文算法都优于由传统方法计算得到的结果。同时,在研究区域分别测量了早中晚三个时间段的土壤CO_2浓度,对其进行去噪处理之后,利用Fick第一定律计算获得的土壤碳通量与LI-8100测得的仅相距1μmol/m^2/s左右。说明通过本文算法不仅精确算得了开放型气室内任意时间任意位置的CO_2浓度时间序列,并且通过计算处理后的时间序列获得了与LI-8100相近的土壤碳通量。 展开更多
关键词 小波包变换 时间序列去噪 fick定律 土壤CO2浓度 土壤碳通量
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Brownian Motion of Decaying Particles: Transition Probability, Computer Simulation, and First-Passage Times 被引量:2
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作者 M. P. Silverman 《Journal of Modern Physics》 2017年第11期1809-1849,共41页
Recent developments in the measurement of radioactive gases in passive diffusion motivate the analysis of Brownian motion of decaying particles, a subject that has received little previous attention. This paper report... Recent developments in the measurement of radioactive gases in passive diffusion motivate the analysis of Brownian motion of decaying particles, a subject that has received little previous attention. This paper reports the derivation and solution of equations comparable to the Fokker-Planck and Langevin equations for one-dimensional diffusion and decay of unstable particles. In marked contrast to the case of stable particles, the two equations are not equivalent, but provide different information regarding the same stochastic process. The differences arise because Brownian motion with particle decay is not a continuous process. The discontinuity is readily apparent in the computer-simulated trajectories of the Langevin equation that incorporate both a Wiener process for displacement fluctuations and a Bernoulli process for random decay. This paper also reports the derivation of the mean time of first passage of the decaying particle to absorbing boundaries. Here, too, particle decay can lead to an outcome markedly different from that for stable particles. In particular, the first-passage time of the decaying particle is always finite, whereas the time for a stable particle to reach a single absorbing boundary is theoretically infinite due to the heavy tail of the inverse Gaussian density. The methodology developed in this paper should prove useful in the investigation of radioactive gases, aerosols of radioactive atoms, dust particles to which adhere radioactive ions, as well as diffusing gases and liquids of unstable molecules. 展开更多
关键词 BROWNIAN Motion Random Walk Diffusion Radioactivity Transition Probability FOKKER-PLANCK EQUATION LANGEVIN EQUATION First Passage ficks law WIENER Process
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Visual analysis of flow and diffusion of hemolytic agents and hematomas
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作者 Yafei Zhu Mengyao Bao +2 位作者 Miaomiao Jiang Jincai Chang Jianzhong Cui 《Visual Computing for Industry,Biomedicine,and Art》 EI 2021年第1期9-21,共13页
The elimination of intracranial hematomas has received widespread attention and the interactions between hemolytic agents and hematomas have become a hot research topic.In this study,we used the Navier-Stokes equation... The elimination of intracranial hematomas has received widespread attention and the interactions between hemolytic agents and hematomas have become a hot research topic.In this study,we used the Navier-Stokes equation to describe the flow control equation for hemolytic agents in a tube and used Fick’s law and the Maxwell-Stefan diffusion theory to describe the diffusion and mass transfer of hemolytic agents and hematomas.The physical fields and initial boundary conditions were set according to the parametric properties of the fluid and drainage tube.The COMSOL Multiphysics software was used to simulate the streamline distribution of hemolytic agents in a bifurcated drainage tube.Additionally,the diffusion behaviors of the hemolytic agents into hematomas were simulated and visual analysis of coupled multiphysics was performed to realize the digitization and visualization of engineering fluid problems and contribute to the field of medical engineering. 展开更多
关键词 Flow diffusion Navier-stokes equation Tube flow ficks law Maxwell-stefan diffusion equation VIsUALIZATION
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Heat and Water Vapour Transfer Trough the Envelope of a Cold Chamber
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作者 Clito Afonso 《Journal of Environmental Science and Engineering(A)》 2016年第7期362-370,共9页
The diffusion of water vapour in the atmospheric air through the elements of the envelope of a cold storage room, caused by the pressure gradient between the external and internal environment is inevitable in most sit... The diffusion of water vapour in the atmospheric air through the elements of the envelope of a cold storage room, caused by the pressure gradient between the external and internal environment is inevitable in most situations. In fact, if the conditions in the interior of an envelope element are such as to enable the vapour freezing of the migrant water, the increase in volume from the formation of ice will causes the deformation of this element with very serious consequences, which can go up to its partial or total destruction. In this scenario, readily note the importance ofvapour barriers associated with a properly designed insulation, tend to not only reduce the amount of water diffused, but also prevent the achievement of the conditions for freeze inside the engaging elements. The purpose of this work is to formulate the procedure for design of vapour barriers connected with the design of optimized thermal insulation, and then apply it to a cold chamber located in Portugal. Vapour barriers and the procedure for its design are both mandatory. The required thickness of the vapour barrier is relatively small, and the most appropriate insolation (maintaining the optimal thickness) is the black cork agglomerate. 展开更多
关键词 Ice formation fick's law vapour barriers cold chamber.
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Equation of Motion of a Mass Point in Gravitational Field and Classical Tests of Gauge Theory of Gravity
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作者 WU Ning ZHANG Da-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3期503-511,共9页
A systematic method is developed to studY the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge fie... A systematic method is developed to studY the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton's second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity. 展开更多
关键词 classical tests of gauge theory of gravity gauge theory of gravity classical solution of field equation Newton's second law of motion
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Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials
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作者 Hong Shih 《Materials Sciences and Applications》 2019年第3期253-292,共40页
In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arre... In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general. 展开更多
关键词 Aluminum spherical Power GAs FLUIDIZATION Bed Oxidation Mechanism Oxide Growth Rate Gibbs Free Energy Ellingham Diagram Mathematical Modeling Dynamic system Plasma DIFFUsION DIFFUsION Coefficient Crystallographic Defect Vacancy Pressure Temperature Flow Laplace Transform Equation Boundary Condition ficks second law software Experimental Theoretical sURGE ARREsTING MATERIALs Analytical solution
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Theoretical Evidence for Wave Nature of Micro Particle and New Theory of Its Collective Motion in Material
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作者 Takahisa Okino 《Journal of Modern Physics》 2021年第3期260-283,共24页
Since a material is composed of micro particles, investigating behavior of those particles is essentially dominant for materials science. The diffusivity of diffusion equation is relevant to not only a collective moti... Since a material is composed of micro particles, investigating behavior of those particles is essentially dominant for materials science. The diffusivity of diffusion equation is relevant to not only a collective motion of micro particles but also a motion of single particle. An elementary process of diffusion was thus theoretically investigated in a local space and time. As a result, the investigation concluded that the wave nature of micro particle results from denying the mathematical density theorem of a real time in the Newton mechanics. In other words, the basic theory of quantum mechanics is established in accordance with the cause-and-effect relationship in the Newton mechanics, for the first time, regardless of the de Broglie hypothesis. In relation to the collective motion of micro particles, the new diffusion theory was also reasonably established using the universal expression of diffusivity obtained here. In the present paper, the new findings indispensable for the fundamental knowledge in physics are thus systematically discussed in accordance with the theoretical frame in physics. 展开更多
关键词 Diffusion ficks laws de Broglie’s Hypothesis schrödinger’s Equation Matter-Wave
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