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Chinese Physics B 2018年第10期27卷 231-239页

作者： J P Singh v t pham t Hayat S Jafari F E Alsaadi B K Roy Department of Electrical Engineering National Institute of Technology Silchar 788010 India School of Electronics and telecommunications Hanoi University of Science and Technology 01 Dai Co Viet Hanoi Viet Nam Department of Mathematics Faculty of Science King Abdulaziz University Jeddah 21589 Saudi Arabia Department of Mathematics Quaid-I-Azam University Islamabad 44000 Pakistan Ambikar University of technology Tehran 15875-4413Iran Department of Information technology Faculty of Computing and IT King Abdulaziz University Jeddah Saudi Arabia

this paper reports a new simple four-dimensional（4 D） hyperjerk chaotic system. the proposed system has only one stable equilibrium point. Hence, its strange attractor belongs to the category of hidden attractors. the proposed system exhibits various dynamical behaviors including chaotic, periodic, stable nature, and coexistence of various attractors. Numerous theoretical and numerical methods are used for the analyses of this system. the chaotic behavior of the new system is validated using circuit implementation. Further, the synchronization of the proposed systems is shown by designing an adaptive integrator backstepping controller. Numerical simulation validates the synchronization strategy.

关键词： new hyperjerk chaotic system stable equilibrium hidden attractors adaptive backstepping control synchronization

Semantic Segmentation of Lumbar vertebrae Using Meijering U-Net(MU-Net)on Spine Magnetic Resonance Images

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 733-757页

作者： Lakshmi S v v Shiloah Elizabeth Darmanayagam Sunil Retmin Raj Cyril Department of Computer Science and Engineering College of Engineering GuindyAnna UniversityChennai600025India Department of Information technology Madras Institute of TechnologyAnna UniversityChrompetChennai600044India

Lower back pain is one of the most common medical problems in the world and it is experienced by a huge percentage of people *** to its ability to produce a detailed view of the soft tissues,including the spinal cord,nerves,intervertebral discs,and vertebrae,Magnetic Resonance Imaging is thought to be the most effective method for imaging the *** semantic segmentation of vertebrae plays a major role in the diagnostic process of lumbar *** is difficult to semantically partition the vertebrae in Magnetic Resonance Images from the surrounding variety of tissues,including muscles,ligaments,and intervertebral discs.U-Net is a powerful deep-learning architecture to handle the challenges of medical image analysis tasks and achieves high segmentation *** work proposes a modified U-Net architecture namely MU-Net,consisting of the Meijering convolutional layer that incorporates the Meijering filter to perform the semantic segmentation of lumbar vertebrae L1 to L5 and sacral vertebra ***-colour mask images were generated and used as ground truth for training the *** work has been carried out on 1312 images expanded from t1-weighted mid-sagittal MRI images of 515 patients in the Lumbar Spine MRI Dataset publicly available from Mendeley *** proposed MU-Net model for the semantic segmentation of the lumbar vertebrae gives better performance with 98.79%of pixel accuracy(PA),98.66%of dice similarity coefficient(DSC),97.36%of Jaccard coefficient,and 92.55%mean Intersection over Union(mean IoU)metrics using the mentioned dataset.

关键词： Computer aided diagnosis(CAD) magnetic resonance imaging(MRI) semantic segmentation lumbar vertebrae deep learning U-Net model

theoretical Investigation on Mechanism, thermochemistry, and Kinetics of the Gas-phase Reaction of 2-Propargyl Radical with Formaldehyde

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Chemical Research in Chinese Universities 2019年第5期35卷 884-891页

作者： tien v.pham School of Chemical Engineering Hanoi University of Science and TechnologyHanoi 10000Vietnam

Gas-phase mechanism and kinetics of the reactions of the 2-propargyl radical(H2CCCH), an important intermediate in combustion processes, with formaldehyde were investigated using ab initio molecular orbital theory at the coupled-cluster CCSD(t)//B3LYP/6-311++G(3df,2p) method in conjunction with transition state theory(tSt), variational transition state theory(vtSt) and Rice-Ramsperger-Kassel-Marcus(RRKM) calculations for rate constants. the potential energy surface(PES) constructed shows that the H2CCCH+HCHO reaction has six main entrances, including two H-abstraction and four additional channels, in which the former is energetically more favorable. the H-abstraction channels slide down to two quite weak pre-complexes COM-01(-9.3 kJ/mol) and COM-02(-kJ/mol) before going via energy barriers of 71.3(t0/P1) and 63.9 kJ/mol(t0/P2), respectively. two post-complexes, COM-1(-17.8 kJ/mol) and COM-2(-23.4 kJ/mol) created just after coming out from t0/P1 and t0/P2, respectively, can easily be decomposed via barrier-less processes yielding H2CCCH2+CHO(P1,-12.4 kJ/mol) and HCCCH3+CHO(P2,-16.5 kJ/mol), respectively. the additional channels occur initially by formation of four intermediate states, H2CCCHCH2O(I1, 1.1 kJ/mol), HCCCH2CH2O(I3, 4.5 kJ/mol), H2CCCHOCH2(I4, 10.2 kJ/mol), and HCCCH2OCH2(I6, 19.1 kJ/mol) via energy barriers of 66.3, 59.2, 112.2, and 98.6 kJ/mol at t0/1, t0/3, tOM, and tO/6, respectively. Of which two channels producing 14 and 16 can be ignored due to coming over tlie high barriers tOM and tO/6, respectively. the rate constants and product branching ratios for the low-energy channels calculated show that the H2CCCH+HCHO reaction is almost pressure-independent. Altliough the H2CCCH+HCHO→Ⅰ1 and H2CCCH+HCHO→Ⅰ3 channels become dominant at low temperature, however, they are less competitive channels at high temperature.

关键词： Reaction mechanism Propargyl radical Formaldehyde Potential energy surface(PES) B3LYP CCSD(t) Rice-Ramsperger-Kassel-Marcus(RRKM) Kinetics

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： pham t.Nhung Do t.Hoai Pierre Darriulat pham tuan-Anh pham N.Diep Nguyen B.Ngoc tran t.thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

On the derivation of the entropy of ideal quantum gases confined in a three-dimensional harmonic potential

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Communications in theoretical Physics 2020年第4期72卷 106-111页

作者： Le tri Dat vinh N t pham Laboratory of Applied Physics Advanced Institute of Materials ScienceTon Duc Thang UniversityHo Chi Minh City 756636Vietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh City 756636Vietnam Ho Chi Minh City University of Education Ho Chi Minh City 748342Vietnam

In this work,the entropy functions of ideal quantum gases in a three-dimensional harmonic trap are analytically calculated using temperature as an explicit ***,the applicability of the analytical formulas is validated by comparison with the numerical *** results illustrate that the obtained functions could be applied for the whole temperature regime with a maximum relative deviation of less than 7.5%in the vicinity of the critical temperature tcin the case of Bose ***,for Fermi gases,although the analytical formula fits well at very low-and high-temperature regimes,it cannot be applied at temperature in the range[0.3-0.5]t_F,where t_F is the Fermi *** addition,the consistency between our formulas and classical ones at significantly high temperatures is also discussed.

关键词： thermodynamic properties entropy 3D harmonic trap ideal quantum gases

Patterns of hepatitis B virus exposure and associated predictors in vietnam: A crosssectional study

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Asian Pacific Journal of tropical Medicine 2020年第12期13卷 535-541页

作者： Minh C.Duong Phuc v.D.Le Oanh N.K.pham Hien D.t.pham toan B.Nguyen Hai t.Phan School of Public Health and Community Medicine University of New South WalesSydneyNew South WalesAustralia MEDIC Medical Center Ho Chi Minh CityVietnam Hospital for tropical Diseases Ho Chi Minh CityVietnam pham Ngoc thach University of Medicine Ho Chi Minh CityVietnam

Objective:to examine the magnitude of isolated anti-HBc and other HBv serological patterns and associated predictors among adults seeking general health check-up at a large health center in ***:All 564 outpatients seeking general health checkup between January 2016 and December 2016 were asked to undertake HBv surface antigen,surface antibody,IgG and IgM core antibody(anti-HBc total),platelet counts,and liver function *** administered questionnaire was used to collect information regarding demography,in-house sources of infection,lifestyle,health condition and treatment,and HBv ***:Male gender(P=0.043),age(P=0.000),living in urban areas(P=0.040),HBv vaccination status(P=0.033),and ALt(P=0.040) were associated with isolated *** infection was associated with HBv vaccination status(P=0.001),ALt levels(P=0.010),ASt levels(P=0.020),and platelet counts(P=0.007).Past/resolved HBv infection was associated with ASt levels(P=0.005),ALt levels(P=0.014),and age(P=0.000).Conclusions:Isolated anti-HBc is quite *** of isolated anti-HBc include male gender,living in rural areas,and HBv *** prevalence of isolated anti-HBc also increases with *** timely detect occult HBv infection and prevent transmission,anti-HBc testing should be included in the health check-up for high risk individuals and screening program where HBv nucleic acid test is not *** prevent transmission,clinicians need to pay more attention on those who are at risk of having isolated anti-HBc and closely follow-up patients with isolated anti-HBc and educate them about the prevention of HBv infection.

关键词： prevention seeking vietnam

Design of a two-dimensional Recursive Filter Using the Bees Algorithm

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International Journal of Automation and computing 2010年第3期7卷 399-402页

作者： D.t.pham Ebubekir Koc Manufacturing Engineering Centre Cardiff University Cardiff CF24 3AA UK

this paper presents the first application of the bees algorithm to the optimisation of parameters of a two-dimensional （2D） recursive digital filter. the algorithm employs a search technique inspired by the foraging behaviour of honey bees. the results obtained show clear improvement compared to those produced by the widely adopted genetic algorithm （GA）.

关键词： Bees algorithm swarm intelligence optimisation two-dimensional digital filter design.

Performances of a new sustainable and durable dry beam-column joints under cyclic and impact loads

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Science China(technological Sciences) 2023年第2期66卷 282-300页

作者： HAO Hong NGO tuan t. pham thong M. LI HuaWei Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityBentley WA 6102Australia the Faculty of Engineering and technology Quy Nhon UniversityBinh Dinh 590000Viet Nam Guangzhou University-Curtin University Joint Research Center for Structural Monitoring and Protection against Multi-Dynamic Hazards School of Civil EngineeringGuangzhou UniversityGuangzhou 510006China

this study investigated the performances of a new type of precast beam-column joint subjected to earthquake and impact *** sustainability and durability considerations,new materials such as corrosion-resistant fibre reinforced polymer(FRP)bolts and reinforcements,fibre reinforced concrete(FRC),and geopolymer concrete(GPC)were used to construct the *** examine the resilience,durability,sustainability,and multi-hazard resistance capacities,both cyclic and pendulum impact tests were carried *** experimental results demonstrated that the proposed precast joints had the comparable or even better performances as compared with the traditional monolithic joints under cyclic and impact *** simulations using ABAQUS were also adopted to determine the optimal values of the concrete-end-plate(CEP)thickness for the proposed dry joints and to further quantify other response parameters which could not be obtained during the test,e.g.,stress distribution,energy absorption,and stress *** on the influences of various parameters on joint performances under different loading conditions was also presented in this study.

关键词： multi-hazards cyclic loads impact loads FRP bolts FRP reinforcements geopolymer concrete fibre-reinforced concrete dry joints ABAQUS

Improving Energy and Power Efficiency Using NComputing and Approaches for Predicting Reliability of Complex Computing Systems

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International Journal of Automation and computing 2010年第2期7卷 153-159页

作者： Hoang pham Hoang pham Jr. Department of Industrial and Systems Engineering Rutgers University timothy Christian School

Opting to follow the computing-design philosophy that the best way to reduce power consumption and increase energy efficiency is to reduce waste, we propose an architecture with a very simple ready-implementation by using an NComputing device that can allow multi-users but only one computer is needed. this intuitively can save energy, space as well as cost. In this paper, we propose a simple and realistic NComputing architecture to study the energy and power-efficient consumption of desktop computer systems by using the NComputing device. We also propose new approaches to estimate the reliability of k-out-of-n systems based on the delta method. the k-out-of-n system consisting of n subsystems works if and only if at least k-of-the-n subsystems work. More specificly, we develop approaches to obtain the reliability estimation for the k-out-of-n systems which is composed of n independent and identically distributed subsystems where each subsystem （or energy-efficient usage application） can be assumed to follow a two-parameter exponential lifetime distribution function. the detailed derivations of reliability estimation of k-out-of-n systems based on the biased-corrected estimator, known as delta method, the uniformly minimum variance unbiased estimate （UMvUE） and maximum likelihood estimate （MLE） are discussed. An energy-management NComputing application is discussed to illustrate the reliability results in terms of the energy consumption usages of a computer system with qua（t-core, 8 GB of RAM, and a GeForce 9800GX-2 graphics card to perform various complex applications. the estimated reliability values of systems based on the UMvUE and the delta method differ only slightly. Often the UMvUE of reliability for a complex system is a lot more difficult to obtain, if not impossible. the delta method seems to be a simple and better approach to obtain the reliability estimation of complex systems. the results of this study also show that, in practice, the NComputing archite

关键词： Energy efficiency Ncomputing k-out-of-n system exponential distribution reliability estimation uniformly minimum variance unbiased estimate (UMvUE) maximum likelihood estimate (MLE).

Examination of n-t_(9) conditions required by N=50,82,126 waiting points in r-process

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Communications in theoretical Physics 2021年第10期73卷 147-157页

作者： Nguyen Duy Ly Nguyen Ngoc Duy Nguyen Kim Uyen vinh N t pham Faculty of Fundamental Sciences Vanlang UniversityHo Chi Minh City 700000Vietnam Department of Physics Sungkyunkwan UniversitySuwon 16419Republic of Korea Department of Physics Ho Chi Minh City University of EducationHo Chi Minh City 700000Vietnam

We examined the conditions of neutron density(n) and temperature(t9) required for the N = 50, 82,and 126 isotopes to be waiting points(WP) in the r-process. the nuclear mass based on experimental data presented in the AME2020 database(AME and AME ± Δ) and that predicted using FRDM,WS4, DZ10, and KtUY models were employed in our estimations. We found that the conditions required by the N = 50 WP significantly overlap with those required by the N = 82 ones, except for the WS4 model. In addition, the upper(or lower) bounds of the n-t9 conditions based on the models are different from each other due to the deviations in the two-neutron separation *** standard deviations in the nuclear mass of 108 isotopes in the three N = 50, 82, and 126 groups are about rms = 0.192 and 0.434 Me v for the pairs of KtUY-AME and WS4-KtUY models,respectively. We found that these mass uncertainties result in a large discrepancy in the nn-t_(9) conditions, leading to significant differences in the conditions for simultaneously appearing all the three peaks in the r-process abundance. the newly updated FRDM and WS4 calculations can give the overall conditions for the appearance of all the peaks but vice versa for their old versions in a previous study. the change in the final r-process isotopic abundance due to the mass uncertainty is from a few factors to three orders of magnitude. therefore, accurate nuclear masses of the r-process key nuclei, especially for 76 Fe,81Cu,127Rh,132Cd,192Dy, and 197tm, are highly recommended to be measured in radioactive-ion beam facilities for a better understanding of the r-process evolution.

关键词： neutron capture r-process nuclear mass isotopic abundance precise mass measurement