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An Improved Solov2 Based on Attention Mechanism and Weighted Loss Function for Electrical Equipment Instance Segmentation
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作者 Junpeng Wu Zhenpeng Liu +2 位作者 Xingfan Jiang Xinguang Tao Ye Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第1期677-694,共18页
The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low precision.Because of the reliable,safe and easy-to-operate technology pro... The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low precision.Because of the reliable,safe and easy-to-operate technology provided by deep learning-based video surveillance for unmanned inspection of electrical equipment,this paper uses the bottleneck attention module(BAM)attention mechanism to improve the Solov2 model and proposes a new electrical equipment segmentation mode.Firstly,the BAM attention mechanism is integrated into the feature extraction network to adaptively learn the correlation between feature channels,thereby improving the expression ability of the feature map;secondly,the weighted sum of CrossEntropy Loss and Dice loss is designed as the mask loss to improve the segmentation accuracy and robustness of the model;finally,the non-maximal suppression(NMS)algorithm to better handle the overlap problem in instance segmentation.Experimental results show that the proposed method achieves an average segmentation accuracy of mAP of 80.4% on three types of electrical equipment datasets,including transformers,insulators and voltage transformers,which improve the detection accuracy by more than 5.7% compared with the original Solov2 model.The segmentation model proposed can provide a focusing technical means for the intelligent management of power systems. 展开更多
关键词 Deep learning electrical equipment attention mechanism weighted loss function
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Computational and bioinformatics tools for understanding disease mechanisms
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作者 MOHD ATHAR ANU MANHAS +1 位作者 NISARG RANA AHMAD IRFAN 《BIOCELL》 SCIE 2024年第6期935-944,共10页
Computational methods have significantly transformed biomedical research,offering a comprehensive exploration of disease mechanisms and molecular protein functions.This article reviews a spectrum of computational tools... Computational methods have significantly transformed biomedical research,offering a comprehensive exploration of disease mechanisms and molecular protein functions.This article reviews a spectrum of computational tools and network analysis databases that play a crucial role in identifying potential interactions and signaling networks contributing to the onset of disease states.The utilization of protein/gene interaction and genetic variation databases,coupled with pathway analysis can facilitate the identification of potential drug targets.By bridging the gap between molecular-level information and disease understanding,this review contributes insights into the impactful utilization of computational methods,paving the way for targeted interventions and therapeutic advancements in biomedical research. 展开更多
关键词 Interaction database Disease mechanisms Protein function Network analysis BIOINFORMATICS Genetic variations Protein-protein interactions Signaling pathways
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The action mechanisms and structures designs of F-containing functional materials for high performance oxygen electrocatalysis 被引量:1
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作者 Gang Wang Shuwei Jia +7 位作者 Hongjing Gao Yewen Shui Jie Fan Yixia Zhao Lei Li Weimin Kang Nanping Deng Bowen Cheng 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第1期377-397,I0010,共22页
Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a cent... Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts. 展开更多
关键词 Fluorine-containing functional materials Action mechanisms and structure designs Density functional theory Oxygen evolution reaction Oxygen reduction reaction
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Effect of Exchange-Correlation Functional on the Structural, Mechanical, and Optoelectronic Properties of Orthorhombic RbSrBr3 Perovskite
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作者 Fatema Najrin Rabeya Bakar Sarna +3 位作者 Md. Alamin Sarker Budrun Neher Md. Mahbubur Rahman Bhuiyan Farid Ahmed 《Materials Sciences and Applications》 2024年第6期137-154,共18页
In the present study, the effect of the exchange-correlation functional on the structural, mechanical, and optoelectronic properties of orthorhombic RbSrBr3 perovskite has been investigated using various functionals i... In the present study, the effect of the exchange-correlation functional on the structural, mechanical, and optoelectronic properties of orthorhombic RbSrBr3 perovskite has been investigated using various functionals in Density Functional Theory (DFT) with the CASTEP code. The optimized lattice parameters are quite similar for all the functionals. The electronic properties have shown that RbSrBr3 perovskite is a wide direct band gap compound with a band gap energy ranging from 4.296 eV to 4.494 eV for all the functionals. The mechanical parameters like elastic constants, Young’s modulus, Shear modulus, Poisson’s ratio, Pugh’s ratio, and an anisotropic factor reveal that the RbSrBr3 perovskite has ductile behavior and an anisotropic nature which signifies the mechanical stability of the compound. The Debye temperature might withstand lattice vibration heat. High absorption coefficient (>104 cm−1), high optical conductivity, and very low reflectivity have been found in the RbSrBr3 perovskite for all functions. The computed findings on the RbSrBr3 perovskite suggested that the presented studied material is potentially applicable for photodetector and optoelectronic devices. 展开更多
关键词 Density functional Theory mechanical Properties PHOTODETECTOR DUCTILITY Anisotropic Factor
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Mechanisms of autophagy function and regulation in plant growth,development,and response to abiotic stress
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作者 Yongbo Li Xiangmin Xu +5 位作者 Guang Qi Dezhou Cui Chen Huang Xinxia Sui Genying Li Qingqi Fan 《The Crop Journal》 SCIE CSCD 2023年第6期1611-1625,共15页
Autophagy is an evolutionarily conserved degradation pathway of lysosomes(in mammals)and vacuoles(in yeasts and plants)from lower yeasts to higher mammals.It wraps unwanted organelles and damaged proteins in a double-... Autophagy is an evolutionarily conserved degradation pathway of lysosomes(in mammals)and vacuoles(in yeasts and plants)from lower yeasts to higher mammals.It wraps unwanted organelles and damaged proteins in a double-membrane structure to transport them to vacuoles for degradation and recycling.In plants,autophagy functions in adaptation to the environment and maintenance of growth and development.This review systematically describes the autophagy process,biological functions,and regulatory mechanisms occurring during plant growth and development and in response to abiotic stresses.It provides a basis for further theoretical research and guidance of agricultural production. 展开更多
关键词 AUTOPHAGY function mechanism DEVELOPMENT Abiotic stresses
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Investigation of the structural, electronic and mechanical properties of CaO–SiO_(2) compound particles in steel based on density functional theory 被引量:1
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作者 Chao Gu Ziyu Lyu +1 位作者 Qin Hu Yanping Bao 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第4期744-755,共12页
CaO–SiO_(2)compounds compromise one of the most common series of oxide particles in liquid steels, which could significantly affect the service performance of the steels as crack initiation sites. However, the struct... CaO–SiO_(2)compounds compromise one of the most common series of oxide particles in liquid steels, which could significantly affect the service performance of the steels as crack initiation sites. However, the structural, electronic, and mechanical properties of the compounds in CaO–SiO_(2)system are still not fully clarified due to the difficulties in the experiments. In this study, a thorough investigation of these properties of CaO–SiO_(2)compound particles in steels was conducted based on first-principles density functional theory. Corresponding phases were determined by thermodynamic calculation, including gamma dicalcium silicate(γ-C2S), alpha-prime(L) dicalcium silicate(αL′-C2S), alpha-prime(H) dicalcium silicate(αH′-C2S), alpha dicalcium silicate(α-C2S), rankinite(C3S2), hatrurite(C3S), wollastonite(CS), and pseudowollastonite(Ps-CS). The results showed that the calculated crystal structures of the eight phases agree well with the experimental results. All the eight phases are stable according to the calculated formation energies, and γ-C2S is the most stable. O atom contributes the most to the reactivity of these phases. The Young’s modulus of the eight phases is in the range of 100.63–132.04 GPa. Poisson’s ratio is in the range of0.249–0.281. This study provided further understanding concerning the CaO–SiO_(2)compound particles in steels and fulfilled the corresponding property database, paving the way for inclusion engineering and design in terms of fracture-resistant steels. 展开更多
关键词 CaO–SiO_(2) density functional theory structural property electronic property mechanical property
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Fluoridation routes,function mechanism and application of fluorinated/fluorine-doped nanocarbon-based materials for various batteries:A review
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作者 Weicui Liu Nanping Deng +5 位作者 Gang Wang Ruru Yu Xiaoxiao Wang Bowen Cheng Jingge Ju Weimin Kang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期363-393,I0011,共32页
With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms... With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications. 展开更多
关键词 Nanocarbon materials Fluorinated/fluorine-doped effect function mechanism Various batteries
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Explanation of Relation between Wave Function and Probability Density Based on Quantum Mechanics in Phase Space
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作者 Chol Jong Jin-Sim Kim +1 位作者 Shin-Hyok Jon Son-Il Jo 《World Journal of Mechanics》 2023年第1期20-72,共53页
The main problem of quantum mechanics is to elucidate why the probability density is the modulus square of wave function. For the purpose of solving this problem, we explored the possibility of deducing the fundamenta... The main problem of quantum mechanics is to elucidate why the probability density is the modulus square of wave function. For the purpose of solving this problem, we explored the possibility of deducing the fundamental equation of quantum mechanics by starting with the probability density. To do so, it is necessary to formulate a new theory of quantum mechanics distinguished from the previous ones. Our investigation shows that it is possible to construct quantum mechanics in phase space as an alternative autonomous formulation and such a possibility enables us to study quantum mechanics by starting with the probability density rather than the wave function. This direction of research is contrary to configuration-space formulation of quantum mechanics starting with the wave function. Our work leads to a full understanding of the wave function as the both mathematically and physically sufficient representation of quantum-mechanical state which supplements information on quantum state given solely by the probability density with phase information on quantum state. The final result of our work is that quantum mechanics in phase space satisfactorily elucidates the relation between the wave function and the probability density by using the consistent procedure starting with the probability density, thus corroborating the ontological interpretation of the wave function and withdrawing a main assumption of quantum mechanics. 展开更多
关键词 Quantum Ensemble Theory Quantum mechanics In Phase Space Wave function Probability Density Schrödinger Equation
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Study of the potential mechanism of acupuncture treatment for functional dyspepsia based on association rule mining and bioinformatics/network pharmacology approach
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作者 An-Lan Zhao Ling-Yong Xiao +2 位作者 Hong-Yue Niu Lian Liu Xiao-Yu Dai 《Gastroenterology & Hepatology Research》 2023年第2期6-15,共10页
Objective:To explore the main acupoint prescription and mechanism of acupuncture in treating Functional dyspepsia(FD)by analyzing the clinical randomized controlled trial literature on acupoints and targets of acupunc... Objective:To explore the main acupoint prescription and mechanism of acupuncture in treating Functional dyspepsia(FD)by analyzing the clinical randomized controlled trial literature on acupoints and targets of acupuncture in the treatment of FD combined with association rule mining and bioinformatics/network pharmacology methods.Methods:Search relevant clinical randomized controlled trial literature on acupoints and therapeutic targets of acupuncture in the treatment of FD from eight databases from their inception to June 18th,2022.We obtained acupuncture selection points,meridian,and therapeutic targets and established acupoints database for acupuncture treatment of FD.FD-related targets were collected from GeneCards,DisGeNET,OMIM,and DrugBank databases.We obtained the potential targets of acupuncture on FD by taking the intersection of acupuncture for FD therapeutic targets and FD-related targets.We performed the protein-protein interaction network,Gene Ontology(GO)analysis,and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway enrichment analysis.Results:In this study,26 Randomized Controlled Trials related to acupuncture treatment of FD were retrieved.We obtained 29 acupoints,17 acupuncture for FD therapeutic targets,and 10 intersection targets.Tumor necrosis factor(TNF),Interleukin(IL)-1,and Neuropeptide Y(NPY)are key targets of acupuncture in the treatment of FD.Conclusion:ST36-CV12-PC6-LR3 is the main acupoint prescription for FD.Acupuncture may affect Neuroactive ligand-receptor interaction,Gastric acid secretion,and IL-17,TNF signaling pathways by regulating related key targets,and play a synergistic role in the treatment of FD by inhibiting gastric acid secretion,alleviating inflammatory response,regulating the brain-gut axis,improving mood and other aspects. 展开更多
关键词 ACUPUNCTURE functional dyspepsia network acupuncture mechanISM
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“Capture-activation-recapture” mechanism-guided design of double-atom catalysts for electrocatalytic nitrogen reduction
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作者 Cheng He Shiqi Yan Wenxue Zhang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期437-447,共11页
Compared with the traditional industrial nitrogen fixation, electrocatalytic methods, especially those utilizing double-atom catalysts containing nonmetals, can give good consideration to the economy and environmental... Compared with the traditional industrial nitrogen fixation, electrocatalytic methods, especially those utilizing double-atom catalysts containing nonmetals, can give good consideration to the economy and environmental protection. However, the existing “acceptance-donation” mechanism is only applicable to bimetallic catalysts and nonmetallic double-atom catalysts containing boron atoms. Herein, a novel “capture-activation-recapture” mechanism for metal-nonmetal double-atom catalyst is proposed to solve the problem by adjusting the coordination environments of nonmetallic atoms and utilizing the activation effect of metal atoms on nitrogen. Based on this mechanism, the nitrogen reduction reaction (NRR) activity of 48 structures is calculated by density functional theory calculation, and four candidates are selected as outstanding electrocatalytic nitrogen reduction catalysts: Si-Fe@NG (U_(L) = –0.14 V), Si-Co@NG (U_(L)= –0.15 V), Si-Mo@BP1 (U_(L) = 0 V), and Si-Re@BP1 (U_(L) = –0.02 V). The analyses of electronic properties further confirm “capture-activation-recapture” mechanism and suggest that the difference in valence electron distribution between metal and Si atoms triggers the activation of N≡N bonds. In addition, a machine learning approach is utilized to generate an expression and an intrinsic descriptor that considers the coordination environment to predict the limiting potential. This study offers profound insight into the synergistic mechanism of TM and Si for NRR and guidance in the design of novel double-atom nitrogen fixation catalysts. 展开更多
关键词 "Capture-activation-recapture"mechanism Double-atom catalyst Nitrogen reduction reaction Density functional theory
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Pyrolysis Mechanisms of Quinoline and Isoquinoline with Density Functional Theory 被引量:4
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作者 凌丽霞 章日光 +1 位作者 王宝俊 谢克昌 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第5期805-813,共9页
The pyrolysis mechanisms of quinoline and isoquinoline were investigated using the density functional theory of quantum chemistry,including eight reaction paths and a common tautomeric intermediate 1-indene imine.It i... The pyrolysis mechanisms of quinoline and isoquinoline were investigated using the density functional theory of quantum chemistry,including eight reaction paths and a common tautomeric intermediate 1-indene imine.It is concluded that the conformational tautomerism of the intermediate decides the pyrolysis products(C6H6,HC≡C—C≡N,C6H5C≡N and HC≡CH)to be the same,and also decides the total disappearance rates of the reactants to be the same,for both original reactants quinoline and isoquinoline during the pyrolysis reaction.The results indicate that the intramolecular hydrogen migration is an important reaction step,which often appears in the paths of the pyrolysis mechanism.The activation energies of the rate determining steps are obtained.The calculated results are in good agreement with the experimental results. 展开更多
关键词 密度泛函理论 热解机理 异喹啉 反应路径 互变异构 氢转移反应 量子化学 热解产物
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Effect of early stepwise cardiopulmonary rehabilitation on function and quality of life in sepsis patients
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作者 Ming-Hui Zheng Wen-Jun Liu Juan Yang 《World Journal of Clinical Cases》 SCIE 2024年第4期729-736,共8页
BACKGROUND Sepsis,as a non-limiting host infection disease,can be accompanied by serious complications such as organ failure,which seriously threatens patient quality of life.AIM To investigate the effect of early ste... BACKGROUND Sepsis,as a non-limiting host infection disease,can be accompanied by serious complications such as organ failure,which seriously threatens patient quality of life.AIM To investigate the effect of early stepwise cardiopulmonary rehabilitation on cardiopulmonary function and quality of life in patients evacuated from mechanical ventilation with sepsis.METHODS A total of 80 patients with sepsis who were hospitalized in our hospital from January 2021 to January 2022 were selected and divided into the observation group(n=40)and the control group(n=40)according to the random number table method.The observation group was treated with early stepwise cardiopulmonary rehabilitation,and the control group was treated with a conventional treatment regimen.Cardiac function indexes(central venous pressure,cardiac troponin I,B-type brain natriuretic peptide),lung function indicators(diaphragmatic mobility,changes in central venous oxygen saturation,oxygenation index),and quality of life(Quality of Life Evaluation Scale)were compared between the two groups after treatment.RESULTS After treatment,the central venous pressure,diaphragm mobility,central venous oxygen saturation,oxygenation index,and Quality of Life Evaluation Scale scores in the observation group were higher than those in the control group,and the differences were statistically significant(P<0.05).The observation group was less than that of the control group for other parameters,and the differences were statistically significant(P<0.05).CONCLUSION Early stepwise cardiopulmonary rehabilitation can effectively enhance cardiac and pulmonary function and improve the quality of life in patients evacuated from mechanical ventilation with sepsis. 展开更多
关键词 Stepwise cardiopulmonary rehabilitation SEPSIS Evacuation of mechanical ventilation Cardiopulmonary function Quality of life
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Laser irradiation effects and its possible mechanisms of action on spermatozoa functions in domestic animals
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作者 Lone SA Mohanty TK +1 位作者 Kumaresan A Bhakat M 《Asian pacific Journal of Reproduction》 2017年第3期97-103,共7页
This article presents a review pertains the laser irradiation effects and its possible mechanisms of action on spermatozoa functions in domestic animals. To improve artificial insemination, laser is sensitive and cost... This article presents a review pertains the laser irradiation effects and its possible mechanisms of action on spermatozoa functions in domestic animals. To improve artificial insemination, laser is sensitive and cost effective technique, when compared to other conventional methods. Laser may have both positive and negative effects on spermatozoa functions. Since the effects of light are mediated by reactive oxygen species, and the levels of these reactive oxygen species following irradiating spermatozoa with laser may be responsible for determining the effects of laser on sperm. Dose of laser may be regarded as of great significance and this dosage of laser may be responsible for determining its effects on spermatozoa. Optimum dosage of laser for improving seminal attributes may vary among various species and this need to be standardized in each of them. The beneficial effects include improving sperm livability, acrosomal integrity, hypo-osmotic swelling response, mitochondrial function and computer-aided sperm analysis parameters. The increase in cytochrome c oxidase activity, ATP levels and mitochondrial membrane potential, in laser irradiated cells may be responsible for enhanced sperm quality parameters. Improving fertility with laser irradiated spermatozoa has been reported in few species like boar and need to be elaborated in other species. In conclusion laser may be regarded as an easy, cheap and time saving technology for improving artificial insemination;in addition, laser may have various potential applications in the field of reproductive biotechnology as well as in livestock farms and veterinary polyclinics. 展开更多
关键词 LASER IRRADIATION SPERMATOZOA function mechanism
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Mathematical Wave Functions and 3D Finite Element Modelling of the Electron and Positron
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作者 Declan Traill 《Journal of Applied Mathematics and Physics》 2024年第4期1134-1162,共29页
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an... The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles. 展开更多
关键词 ELECTRON POSITRON Wave function Solution Electromagnetic Spin Mass Charge Proof Fundamental Particle Properties Quantum mechanics Classical Physics Computer 3D Model Schrödinger Equation RMS KLEIN GORDON Electric Magnetic Lorentz Invariant Hertzian Vector Point Potential Field Density Phase Flow Attraction REPULSION Shell Theorem Ehrenfest VIRIAL Normalization Harmonic Oscillator
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Healthy Functions and Mechanisms of Bamboo-Charcoal Modified Polyesters
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作者 王其 赫淑彩 《Journal of Donghua University(English Edition)》 EI CAS 2007年第6期778-780,共3页
In this paper,healthy functions and mechanisms of bamboo-charcoal modified polyesters are studied.The results show that there are five healthy functions incorporated effectively in bamboo-charcoal modified polyesters,... In this paper,healthy functions and mechanisms of bamboo-charcoal modified polyesters are studied.The results show that there are five healthy functions incorporated effectively in bamboo-charcoal modified polyesters,such as good far-infrared radiation,good UV protection,certain negative ion emission,certain anti-bacteria and good absorption functions.The metal elements and carburets are mainly responsible for far-infrared,negative ion emission functions.UV prevention function results mainly from the carbon elements.The absorbability and bacteriostasis functions lie in the porous structures. 展开更多
关键词 竹-炭改良聚酯 保健功能 保健机制 功能纤维
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Oligomerization of drug transporters:Forms,functions,and mechanisms
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作者 Chunxu Ni Mei Hong 《Acta Pharmaceutica Sinica B》 SCIE CAS CSCD 2024年第5期1924-1938,共15页
Drug transporters are essential players in the transmembrane transport of a wide variety of clinical drugs.The broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmaco... Drug transporters are essential players in the transmembrane transport of a wide variety of clinical drugs.The broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical significance.With our accumulating knowledge on the three-dimensional structure of drug transporters,their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification(PTM).In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins,provide clues for the development of novel drugs,and improve the therapeutic efficacy.In this review,we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies,summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins,and discuss the regulatory mechanisms of oligomerization.Finally,we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM. 展开更多
关键词 Drug development Drug transporters OLIGOMERIZATION Protein expression Protein–protein interaction Regulatory mechanism Structural basis Transport function
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Recent Advances in Deciphering the Mechanisms and Biological Functions of DNA Demethylation
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作者 Yang Feng Sheng-Jun Chen Bi-Feng Yuan 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2024年第6期645-651,共7页
5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TE... 5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA demethylation.In this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,respectively.Additionally,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),respectively.Various DNA demethylation pathways possess critical functional implications and roles in biological processes.This Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC. 展开更多
关键词 EPIGENETICS DNA DNA methylation 5-Methylcytosine DEMETHYLATION mechanisms Biological functions C—C bond cleavage Mass spectrometry
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Theoretical Studies on Reaction Mechanisms of HNCS with NH(X^3Σ) 被引量:8
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作者 LIU Peng-jun ZHANG Lian-hua +2 位作者 SUN Hao CHANG Ying-fei WANG Rong-shun 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2006年第5期635-638,共4页
The reaction mechanisms of HNCS with NH(X^3∑ ) were theoretically investigated. The minimum energy paths (MEP) of the reaction were calculated by using the density functional theory(DFT) at the B3LYP/6-311 + ... The reaction mechanisms of HNCS with NH(X^3∑ ) were theoretically investigated. The minimum energy paths (MEP) of the reaction were calculated by using the density functional theory(DFT) at the B3LYP/6-311 + + G^** level. The equilibrium structural parameters, the harmonic vibrational frequencies, the total energies, and the zeropoint energies(ZPE) of all the species were calculated. The single-point energies along the MEP were further refined at the QCISD(T)/6-311 + + G^* * level. It was found that the mechanisms of the HNCS + NH(X^3∑) reaction involve two channels producing the HNC + HNS and the N2H2 + CS products. Channel 1 plays a dominant role and the HNC + HNS are the main preduets. The reaction is exothermie. 展开更多
关键词 HNCS NH(X^3∑) Reaction mechanism Density functional theory(DFT)
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Effect of Graphene Surface Functional Groups on the Mechanical Property of PMMA Microcellular Composite Foams 被引量:3
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作者 李美娟 CHENG Ping +2 位作者 LIU Cheng 沈强 ZHANG Lianmeng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第3期717-722,共6页
The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate (PMMA) microcellular foams reinforced w... The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate (PMMA) microcellular foams reinforced with graphene oxide (GO) and reduced graphene oxide (RGO) to investigate this influence of functional groups. RGO sheets were fabricated by solvent thermal reduction in DMF medium. UV-Vis, FT-IR and XPS analyses indicate the difference of oxygen-containing groups on GO and RGO sheets surface. The observation of SEM illustrates that the addition of a smaller number of GO or RGO sheets causes a fine cellular structure of PMMA foams with a higher cell density(about 1011 cells/cm3) and smaller cell sizes (about 1 -2 jim) owing to their remarkable heterogeneous nucleation effect. Compared to GO reinforced foams, the RGO/PMMA foams own lower cell density and bigger cell size in their microstructure, and their compressive strength is lower even when the reinforcement contents are the same and the foam bulk density is higher, These results indicate that the oxygen-containing groups on GO sheets' surface are beneficial to adhere CO2 to realize a larger nucleation rate, and their strong interaction with PMMA matrix improves the mechanical property of PMMA foams. 展开更多
关键词 GRAPHENE surface functional GROUPS PMMA MICROCELLULAR COMPOSITE FOAMS mechanical property
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Formation mechanism of methane during coal evolution:A density functional theory study 被引量:2
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作者 Lina Zhang Lixia Ling +2 位作者 Senpeng Zhao Riguang Zhang Baojun Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第5期669-678,共10页
The formation mechanism of methane (CH4) during coal evolution has been investigated by density functional theory (DFT) of quantum chemistry. Thermogenic gas, which is generated during the thermal evolution of med... The formation mechanism of methane (CH4) during coal evolution has been investigated by density functional theory (DFT) of quantum chemistry. Thermogenic gas, which is generated during the thermal evolution of medium rank coal, is the main source of coalbed methane (CBM). Ethylbenzene (A) and 6,7-dimethyl-5,6,7,8-tetrahydro-1-hydroxynaphthalene (B) have been used as model compounds to study the pyrolysis mechanism of highly volatile bituminous coal (R), according to the similarity of bond orders and bond lengths. All possible paths are designed for each model. It can be concluded that the activation energies for H-assisted paths are lower than others in the process of methane formation; an H radical attacking on β-C to yield CH4 is the dominant path for the formation of CH4 from highly volatile bituminous coal. In addition, the calculated results also reveal that the positions on which H radical attacks and to which intramolecular H migrates have effects on methyl cleavage. 展开更多
关键词 coalbed methane highly volatile bituminous coal formation mechanism density functional theory KINETICS
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