Journal of the Korean Physical Society最新文献_第2页

Properties of multifractality in time series of the Sun’s magnetic parameters

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-27 DOI: 10.1007/s40042-025-01293-x

Eo-Jin Lee, Sung-Hong Park

{"title":"Properties of multifractality in time series of the Sun’s magnetic parameters","authors":"Eo-Jin Lee, Sung-Hong Park","doi":"10.1007/s40042-025-01293-x","DOIUrl":"10.1007/s40042-025-01293-x","url":null,"abstract":"<div>The magnetic field in solar active regions (ARs) evolves dynamically and can play an important role in triggering solar flares as one of the Sun’s major eruptive phenomena. It is, therefore, crucial to better understand the time-varying magnetic field in ARs in relation to flare occurrence. Here we applied the multifractal detrended fluctuation analysis (MF-DFA) method to time series of various magnetic parameters derived from the observed magnetic field in the photospheric surface of a total of 236 ARs consisting of 118 flare-quiet and 118 flaring cases. As a result, the nature of multifractality in various levels was identified in all the investigated time series of solar magnetic parameters. Comparing properties of multifractality in the time series of the flare-quiet versus flaring ARs, we first found that the magnetic parameter time series of the flaring ARs tend to have a higher generalized Hurst exponent than those of the flare-quiet ARs. Through the Student’s t-test, it was also found that the distribution of generalized Hurst exponents is statistically different between the magnetic parameter time series of the flare-quiet and flaring ARs. In addition, for most of the magnetic parameters under investigation, the multifractal spectra derived from the relevant time series exhibit a higher degree of left truncation in the case of the flare-quiet ARs compared to the flaring ARs. These results support the fact reported in previous studies that the magnetic field in flaring ARs is more dynamic in terms of its rapid and large variations prior to and around times of flare occurrence. We expect that further detailed analysis of multifractality in time series of the Sun’s various physical quantities not only in the photosphere but also in the upper atmosphere may help us to better understand the fundamental physics of solar eruptive phenomena.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 5","pages":"452 - 472"},"PeriodicalIF":0.8,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamics, stationary distribution and application of a stochastic SIRS model with Stratonovich perturbation

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-23 DOI: 10.1007/s40042-025-01288-8

Hongjie Fan, Kai Wang, Yanling Zhu

{"title":"Dynamics, stationary distribution and application of a stochastic SIRS model with Stratonovich perturbation","authors":"Hongjie Fan, Kai Wang, Yanling Zhu","doi":"10.1007/s40042-025-01288-8","DOIUrl":"10.1007/s40042-025-01288-8","url":null,"abstract":"<div>In this paper, we investigate the Stratonovich stochastic SIRS model with the nonlinear incidence rate. Firstly, the existence and uniqueness of the globally positive solution to the stochastic model are obtained by constructing suitable Lyapunov function. Then it’s worth noting that the basic reproduction number of Stratonovich model ({R}_0) is the same as that of the deterministic model. And when ({R}_0>1), we obtain the low bound of the number of infected people in mean, which is less than that of It({hat{o}}) model. Moreover, there is a unique stationary distribution to the model when ({{hat{R}}}_0) is greater than one. Finally, in numerical simulations, all the theoretical results are verified by Milstein’s higher-order method, where the dynamical behaviors, the sufficient conditions for the existence of the stationary distribution and changes of kernel densities over time are depicted or calculated in detail. In addition, we obtain and fit the real data of COVID-19 in Australia, which further demonstrates the practicability of the model in the real world.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 5","pages":"435 - 451"},"PeriodicalIF":0.8,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Molecular structure and vapor pressure of molybdenum pentachloride using ab-initio thermodynamics

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-20 DOI: 10.1007/s40042-025-01287-9

Na-Young Lee, Sun-Hye Kim, Jong-Yoon Kim, Yeong-Cheol Kim

引用次数: 0

Detecting chaotic nature of orbits in global dynamics by permutation entropy of power spectrum

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-17 DOI: 10.1007/s40042-024-01272-8

Beyrul Canbaz

引用次数: 0

Oscillatory dependence of tunneling magnetoresistance on barrier thickness in magnetic tunnel junctions

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-17 DOI: 10.1007/s40042-024-01281-7

B. C. Lee

引用次数: 0

Time-dependent Taylor–Couette flow in an annulus partially filled with porous material

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-17 DOI: 10.1007/s40042-024-01283-5

Taiwo S. Yusuf, Basant K. Jha

{"title":"Time-dependent Taylor–Couette flow in an annulus partially filled with porous material","authors":"Taiwo S. Yusuf, Basant K. Jha","doi":"10.1007/s40042-024-01283-5","DOIUrl":"10.1007/s40042-024-01283-5","url":null,"abstract":"<div>The current investigation examines the time-dependent dynamics of fluid within a system composed of two coaxial rotating cylinders partially filled with clear fluid and fluid saturated with isotropic porous material of uniform permeability. The fluid motion is induced by the time-dependent exponential decay/growth boundary motion of the two cylinders. Through the utilization of the semi-analytical methodology, which incorporates the Laplace transform technique and the Riemann-sum approximation approach, a comprehensive examination is conducted on the interaction between the transparent fluid and the isotropic porous medium, as well as the influence of the time-dependent exponential decay or growth boundary condition on both surfaces. The results encompass the influence of different factors entering the dimensionless model. It is demonstrated that the velocity of the fluid in the area containing porous material is increased when the inner cylinder experiences exponential growth. The shear stress at both cylinders can be controlled by taking into account the suitable time-dependent exponential growth/decay at the surfaces.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 6","pages":"486 - 500"},"PeriodicalIF":0.8,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of growth conditions for high-Ge-content Si1-xGex epitaxial layers using ultra-high-vacuum CVD for high-performance semiconductor applications

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-16 DOI: 10.1007/s40042-024-01261-x

Ji-Hoon Kim, Jea-Gun Park

{"title":"Optimization of growth conditions for high-Ge-content Si1-xGex epitaxial layers using ultra-high-vacuum CVD for high-performance semiconductor applications","authors":"Ji-Hoon Kim, Jea-Gun Park","doi":"10.1007/s40042-024-01261-x","DOIUrl":"10.1007/s40042-024-01261-x","url":null,"abstract":"<div>As semiconductor devices scale down, integrating high Ge content Si1-xGex epitaxial layers has become crucial for enhancing device performance in Dynamic Random-Access Memory (DRAM) and logic structures like Fin Field-Effect Transistors (FETs) and Gate-All-Around (GAA) FETs. This study investigates the growth of defect-free Si1-xGex layers using ultra-high vacuum chemical vapor deposition (UHV-CVD) with a focus on optimizing growth parameters, including temperature, gas ratios, and boron doping levels, to achieve high Ge concentrations and smooth surfaces. Growth experiments were conducted across temperatures from 450 to 700 ℃, with optimal conditions observed at 530 ℃ and a Si2H6 gas ratio of 1:4.2, producing a defect-free Si1-xGex layer with 46 at% Ge. Temperature effects revealed that managing hydrogen desorption rates were critical for enhancing Ge incorporation while minimizing defects. Strain-induced roughness was mitigated through precise control of Si2H6 ratios, essential at high Ge levels. Boron incorporation was adjusted using diborane (B2H6) flow rates, where an optimal rate of 50 sccm resulted in a boron concentration of 2.7 × 1020 atoms/cm3, achieving a balance between dopant levels and surface smoothness. These findings highlight the importance of managing growth parameters to ensure both material stability and electrical properties, supporting the advancement of high-performance semiconductor devices with superior scalability and reliability.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 5","pages":"422 - 429"},"PeriodicalIF":0.8,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A numerical study on the radiative flow of magneto-Casson fluid via a vertical microchannel with entropy generation

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-16 DOI: 10.1007/s40042-025-01289-7

P. Sreehari, D. Gopal, N. Kishan, K. Venkadeshwaran, Shivender Singh, K. Karthik

{"title":"A numerical study on the radiative flow of magneto-Casson fluid via a vertical microchannel with entropy generation","authors":"P. Sreehari, D. Gopal, N. Kishan, K. Venkadeshwaran, Shivender Singh, K. Karthik","doi":"10.1007/s40042-025-01289-7","DOIUrl":"10.1007/s40042-025-01289-7","url":null,"abstract":"<div>The current study explores the influence of thermal radiation on the flow of Casson liquid via a vertical microchannel in the presence of a magnetic field. Furthermore, the investigation of entropy generation may indicate options for increasing heat transport inside the microchannel. Entropy addresses the particular arrangement of particles and the principles of entropy as they pertain to a specific combination of measurements for temperature, pressure, and volume inside a microchannel of the system. Applications of entropy generation in nuclear energy: despite the substantial energy output of nuclear reactions, the earth has a finite supply of materials essential for these processes. The modeled governing partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) with the aid of similarity variables. The obtained ODEs are solved numerically by employing Runge–Kutta–Fehlberg’s fourth-fifth order (RKF-45) scheme. The influence of relevant parameters on Bejan number, entropy generation, velocity, and temperature is discussed graphically. The obtained outcomes are compared with the earlier available results. The upsurge in radiation parameter (1, 1.5, 2, 2.5) values declines the velocity. Results reveal that the heat transport declines for higher radiation parameter (1, 1.5, 2, 2.5) and magnetic parameter (1, 3, 6, 9) values. Entropy generation decreases with the increase in the Brinkman number and magnetic parameter, the reverse trend is observed for the radiation parameter.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 5","pages":"372 - 382"},"PeriodicalIF":0.8,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Increase in dye-loading amounts and photovoltaic performance of dye-sensitized solar cells with the aid of electrostatic force

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-15 DOI: 10.1007/s40042-025-01285-x

Gyeongbeom Ryoo, Seokhun Shin, Ju Hee Gu, Tae Won Hwang, Kyung-Hye Jung, Yoon Soo Han

{"title":"Increase in dye-loading amounts and photovoltaic performance of dye-sensitized solar cells with the aid of electrostatic force","authors":"Gyeongbeom Ryoo, Seokhun Shin, Ju Hee Gu, Tae Won Hwang, Kyung-Hye Jung, Yoon Soo Han","doi":"10.1007/s40042-025-01285-x","DOIUrl":"10.1007/s40042-025-01285-x","url":null,"abstract":"<div>An electrostatic attraction method was applied to reduce the dye-adsorption time in the fabrication of dye-sensitized solar cells (DSCs). Lead cations (LCs) were first deposited onto the surfaces of TiO2 electrodes, and then, the electrodes were sensitized with Z907 dyes. Owing to the electrostatic attraction between the positive charges on the TiO2 surfaces and the carboxylate anions (–COO−) in the Z907 dye molecules, more dyes were adsorbed onto the LC-deposited TiO2 surfaces, which required only 1 h for dyeing, than in a reference TiO2 electrode that was dyed for 4 h. Only-1-h-sensitized cells prepared from the LC-deposited TiO2 electrodes showed higher power conversion efficiencies (PCEs) than 4-h-sensitized devices, which were fabricated using pristine TiO2 electrodes without LCs. A higher dye-loading amount in the 1-h-sensitized cells led to retardation in the back electron transfer, and an enhancement in both light harvesting and electron collection efficiencies. These induced an enhancement in both the open-circuit voltage and short-circuit current in the 1-h-sensitized cells, compared to those of the reference cells. The electrostatic attraction method by the deposition of LCs could lead to an improvement in the PCEs of DSCs as well as a significant reduction in the dye-adsorption time.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 4","pages":"315 - 323"},"PeriodicalIF":0.8,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of thermal annealing on the abrupt transition behavior of TiOx and TaOx resistive memories

IF 0.8 4区物理与天体物理

Journal of the Korean Physical Society Pub Date : 2025-01-09 DOI: 10.1007/s40042-024-01284-4

Arman Kadyrov, Shubham Patil, Junseong Bae, Anupom Devnath, Jinsu Choi, Seunghyun Lee

{"title":"Impact of thermal annealing on the abrupt transition behavior of TiOx and TaOx resistive memories","authors":"Arman Kadyrov, Shubham Patil, Junseong Bae, Anupom Devnath, Jinsu Choi, Seunghyun Lee","doi":"10.1007/s40042-024-01284-4","DOIUrl":"10.1007/s40042-024-01284-4","url":null,"abstract":"<div>This study presents a comprehensive comparison of Tantalum Oxide (TaOx) and Titanium Oxide (TiOx) structures deposited with the sputtering method and further annealed at temperatures below 300 °C in the context of their integration into RRAM technologies. The results show that TiOx structure exhibits superior performance at a higher temperature threshold of 150 °C, while TaOx is optimized for a lower manufacturing temperature of 70 °C. Thermal stability and resistive switching characteristics of both structures have been verified. The findings indicate that TiOx structure’s robustness at elevated temperatures correlates with enhanced memory window and lower current levels during the SET cycle, making it a viable candidate for sub-150 °C applications. Conversely, TaOx demonstrates commendable energy efficiency and reliability at lower operational temperature, suggesting its suitability for energy-sensitive environments. Both structures were manufactured at temperatures lower than conventional Chemical Vapor Deposition (CVD) and thermal annealing methods, which makes them CMOS-compatible and applicable in back-end-of-the-line semiconductor fabrication.</div>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":"86 4","pages":"342 - 348"},"PeriodicalIF":0.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143388773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0