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Existence of Equilibrium Points in the R3BP with Variable Mass When the Smaller Primary is an Oblate Spheroid

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International Journal of Astronomy and Astrophysics 2017年第2期7卷 45-61页

作者： M. R. hassan Sweta Kumari md. aminul hassan Department of Mathematics S. M. College T. M. Bhagalpur University Bhagalpur India Research Scholar T. M. Bhagalpur University Bhagalpur India GTE Bangalore India

The paper deals with the existence of equilibrium points in the restricted three-body problem when the smaller primary is an oblate spheroid and the infinitesimal body is of variable mass. Following the method of small parameters;the co-ordinates of collinear equilibrium points have been calculated, whereas the co-ordinates of triangular equilibrium points are established by classical method. On studying the surface of zero-velocity curves, it is found that the mass reduction factor has very minor effect on the location of the equilibrium points;whereas the oblateness parameter of the smaller primary has a significant role on the existence of equilibrium points.

关键词： Restricted Three-Body Problem Jean’s Law Space-Time Transformation Oblateness Equilibrium Points Surface of Zero-Velocity

Libration Points in the R3BP with a Triaxial Rigid Body as the Smaller Primary and a Variable Mass Infinitesimal Bod

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International Journal of Astronomy and Astrophysics 2019年第1期9卷 21-38页

作者： M. R. hassan Sweta Kumari R. R. Thapa md. aminul hassan Department of Mathematics S. M. College T. M. Bhagalpur University Bhagalpur India T. M. Bhagalpur University Bhagalpur India Department of Mathematics P. G. Campus Tribhuvan University Biratnagar Nepal GTE Bangalore India

The paper deals with the existence of the coplanar libration points in the restricted three-body problem when the smaller primary is a triaxial rigid body and the infinitesimal body is of variable mass. Following small parameter method, the coordinates of collinear libration points are established whereas the coordinates of triangular libration points are established by classical method. It is found that the mass reduction factor has small effect but triaxiality parameters of the smaller primary have great effects on the coordinates of the libration points.

关键词： Restricted Three-Body Problem Jean’s Law Space-Time Transformation Triaxiality Mass Reduction Factors Libration Points

Effect of Resonance on the Motion of Two Cylindrical Rigid Bodies

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International Journal of Astronomy and Astrophysics 2016年第4期6卷 555-574页

作者： M. R. hassan Baby Kumari md. aminul hassan Payal Singh B. K. Sharma P. G. Department of Mathematics S. M. College T. M. Bhagalpur University Bhagalpur India Research Scholar T. M. Bhagalpur University Bhagalpur India GTE Yeshwanthpur Bangalore India Department of Mathematics SBS College University of Delhi New Delhi India

The effect of resonance on the motion of two cylindrical rigid bodies has been studied in the light of Bhatnagar [1] [2] [3] and under some defined axiomatic restrictions. Here we have calculated variation in Eulerian... 详细信息

关键词： Inertia Ellipsoid Ellipsoids of Revolution Symmetrical Bodies Orientation of the Bodies Principal Axes Eulerian Angles Critical Points Perturbations Averaging of Hamiltonian Resonance

Periodic Orbits of the First Kind in the Autonomous Four-body Problem with the Case of Collision

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International Journal of Astronomy and Astrophysics 2017年第2期7卷 91-111页

作者： M. R. hassan md. aminul hassan Payal Singh Vinay Kumar R. R. Thapa Department of Mathematics S. M. College T. M. Bhagalpur University Bhagalpur India GTE Bangalore India Research Scholar T. M. Bhagalpur University Bhagalpur India Department of Mathematics Zakir Hussain College University of Delhi New Delhi India Department of Mathematics P. G. Campus Tribhuvan University Biratnagar Nepal

In this manuscript, the existence of periodic orbits of collision of the first kind has been discussed on the model of Autonomous Four-body Problem by the method of analytic continuation given by Giacaglia [1] and Bhatnagar [2] [3]. For the existence of periodic orbits, Duboshin’s criterion [4] has been satisfied and it has been confirmed by analyzing the Poincare surfaces of section (PSS) [5]. Also it has been shown that the case of collision given by Levi-Civita [6] [7] is conserved by the method analytic continuation. In all sections of this manuscript, equilateral triangular configuration given by Ceccaroni and Biggs [8] has been considered. In this model, third primary of L4 inferior mass (in comparison of the other primaries) is placed at the equilibrium point of the R3BP.

关键词： Autonomous Four-Body Problem Regularization Periodicity Poincare Surfaces of Section Collision Orbit Zero Velocity Curves

Status and prospects for symmetric organic redox flow batteries

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Journal of Energy Chemistry 2025年第1期100卷 125-143页

作者： md.Al Raihan C.Adam Dyker Department of Chemistry University of New Brunswick

As environmental concerns from fossil fuel consumption intensify, large-scale energy storage becomes imperative for the integration of renewable sources like wind, hydro, and solar with the electrical *** flow batteries, particularly those employing organic molecules, are positioned as a key technology for this purpose. This review explores the growing field of symmetric organic redox flow batteries(ORFBs) within this context. Unlike traditional asymmetric designs based on unique active materials for each electrode, symmetric ORFBs involve a single bipolar species for both electrodes. This review highlights the benefits of a symmetric design, and categorizes five distinct classes of organic bipolar molecules used in both aqueous and non-aqueous solvents. By providing a comprehensive overview of their cell cycling and performance characteristics, the strengths and weaknesses of the diverse categories of bipolar molecules are highlighted for both solvent systems, as are opportunities for future development. This should guide new research directions and advance the development of practical symmetric ORFBs.

关键词： Redox flow battery Symmetric battery Organic battery Aqueous electrolyte Non-aqueous electrolyte

Regeneration mechanisms and therapeutic strategies for neuromuscular junctions in aging and diseases

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Neural Regeneration Research 2025年第1期20卷 193-194页

作者： Masashi Fujitani Abu md.Mamun Tarif Yoshinori Otani Department of Anatomy and Neuroscience Faculty of MedicineShimane UniversityShimaneJapan

The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout *** NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022).

关键词： aging structure Figure

Steel Surface Defect Detection Using Learnable Memory Vision Transformer

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Computers, Materials & Continua 2025年第1期82卷 499-520页

作者： Syed Tasnimul Karim Ayon Farhan md.Siraj Jia Uddin Department of Computer Science and Engineering BRAC UniversityDhaka1212Bangladesh Department of AI and Big Data Endicott CollegeWoosong UniversityDaejeon34606Republic of Korea

This study investigates the application of Learnable Memory Vision Transformers(LMViT)for detecting metal surface flaws,comparing their performance with traditional CNNs,specifically ResNet18 and ResNet50,as well as other transformer-based models including Token to Token ViT,ViT withoutmemory,and Parallel *** awidely-used steel surface defect dataset,the research applies data augmentation and t-distributed stochastic neighbor embedding(t-SNE)to enhance feature extraction and *** techniques mitigated overfitting,stabilized training,and improved generalization *** LMViT model achieved a test accuracy of 97.22%,significantly outperforming ResNet18(88.89%)and ResNet50(88.90%),aswell as the Token to TokenViT(88.46%),ViT without memory(87.18),and Parallel ViT(91.03%).Furthermore,LMViT exhibited superior training and validation performance,attaining a validation accuracy of 98.2%compared to 91.0%for ResNet 18,96.0%for ResNet50,and 89.12%,87.51%,and 91.21%for Token to Token ViT,ViT without memory,and Parallel ViT,*** findings highlight the LMViT’s ability to capture long-range dependencies in images,an areawhere CNNs struggle due to their reliance on local receptive fields and hierarchical feature *** additional transformer-based models also demonstrate improved performance in capturing complex features over CNNs,with LMViT excelling particularly at detecting subtle and complex defects,which is critical for maintaining product quality and operational efficiency in industrial *** instance,the LMViT model successfully identified fine scratches and minor surface irregularities that CNNs often *** study not only demonstrates LMViT’s potential for real-world defect detection but also underscores the promise of other transformer-based architectures like Token to Token ViT,ViT without memory,and Parallel ViT in industrial scenarios where complex spatial relationships are *** research m

关键词： Learnable Memory Vision Transformer(LMViT) Convolutional Neural Networks(CNN) metal surface defect detection deep learning,computer vision image classification learnable memory gradient clipping label smoothing t-SNE visualization

MOVPE Growth of In_xGa_(1-x)N(x～0.4) and Fabrication of Homo-junction Solar Cells

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Journal of Materials Science & Technology 2013年第2期29卷 128-136页

作者： md. Rafiqul Islam md. Rejvi Kaysir md. Jahirul Islam A. Hashimoto A. Yamamoto Department of Electrical and Electronic Engineering KUETKhulna 9203 Bangladesh Graduate School of Engineering University of Fukui 3-9-1 BunkyoFukui 910-8507 Japan

The metal organic vapor phase epitaxy （MOVPE） growth of indium gallium nitride （InGaN） has been discussed in detail towards the fabrication of solar cell. The InGaN film with In contents up to 0.4 are successfully grown by controlling the fundamental growth parameters such as the precursor gas flow rates, temperature etc. The formation of metallic In originates from the higher value （0.74） of trimethylindium/ （trimethylindium ＋ triethylgallium）（TMI/（TMI ＋ TEG）） molar ratio with low （4100） V/lll weight molar ratio while the lower value （0.2） of TMI/（TMI ＋ TEG） causes the phase separation. It is also necessary to control the growth rate and epitaxial film thickness to suppress the phase separation in the material. The crystalline quality of grown films is studied and it is found to be markedly deteriorated with increasing In content. The lattice parameters as well as the thermal expansion coefficient mismatch between GaN template and InGaN epi-layer are primarily considered as the reasons to deteriorate the film quality for higher In content. By using Ino.16Ga0.84N films, an n＋-p homo-junction structure is fabricated on 0.65 μm GaN template. For such a device, the response to the light illumination （AM 1.5） is observed with an open circuit voltage of 1.4 V and the short circuit current density of 0.25 mA/cm2. To improve the performance as well as increase solar photon capturing, the device is further fabricated on thick GaN template with higher In content. The In0.25Ga0.75N n＋-p junction solar cell is found better performance with an open circuit voltage of 1.5 V and the short circuit current density of 0.5 mA/cm2. This is the InGaN p-n homo-junction solar cell with the highest In content ever reported by MOVPE.

关键词： InGaN Metal organic vapor phase epitaxy (MOVPE) Growth Film quality Doping p-n junction

Ignored Engagement: A Piloted Theory about Social Aspects of Aging

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Advances in Aging Research 2023年第4期12卷 49-55页

作者： md. aminul Islam Department of Sociology University of Rajshahi Rajshahi Bangladesh

The society and culture of Bangladesh are quite different from the other countries of the world. It is difficult to receive a theory fully for explaining the condition of our own. However, the purpose of this paper is to review major sociological theories on aging and propose a new one. Data were collected from both primary and secondary sources. Content analysis and survey methods were used in this study. Through the baseline survey of four villages in the Bogra District of Bangladesh, 609 older people have been identified. Among them, 203 older people including 96 males and 107 females have been selected as a sample randomly and interviewed intensively. The contents of aging-related theories have been analyzed. The results of this study show that existing theories of aging are inadequate to explain the social aspects of older adults in Bangladesh;rather Ignored Engagement (A Piloted Theory) may be suitable to do this. This study may give future direction to academicians and policymakers to formulate and amend evidence-based policies and practices for the well-being of our older people.

关键词： Theory Aging Wellbeing Role Status