检索结果-南通市图书馆

Wireless Sensor Network 2012年第1期4卷 18-24页

作者： md. asif khan Israfil Tamim Emd.d Ahmed M. Abdul Awal 不详

In wireless sensor network cluster architecture is useful because of its inherent suitability for data fusion. In this paper we represent a new approach called Multiple Parameter based Clustering (MPC) embedded with the traditional k-means algorithm which takes different parameters (Node energy level, Euclidian distance from the base station, RSSI, Latency of data to reach base station) into consideration to form clusters. Then the effectiveness of the clusters is evaluated based on the uniformity of the node distribution, Node range per cluster, Intra and Inter cluster distance and required energy level of each centroid. Our result shows that by varying multiple parameters we can create clusters with more uniformly distributed nodes, minimize intra and maximize inter cluster distance and elect less power consuming centroid.

关键词： K-Means Algorithm Energy Efficient Uniform Distribution RSSI Latency

Status and prospects for symmetric organic redox flow batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Design and simulation to improve the structural efficiency of green light emission of GaN/InGaN/AIGaN light emitting diode

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2017年第4期10卷 370-377页

作者： Sakhawat HUSSAIN Tasnim ZERIN md. Ashik khan Department of Electrical and Electronic Engineering University of Dhaka Dhaka-1000 Bangladesh

This study considered the design of an efficient, high brightness polar InGaN/GaN light emitting diode （LED） structure with A1GaN capping layer for green light emission. The deposition of high In （〉 15%） composition within InGaN quantum well （QW） has limitations when providing intense green light. To design an effective model for a highly efficient InGaN green LEDs, this study considered the compositions of indium and aluminum for InxGal xN QW and AlyGal yN cap layers, along with different layer thicknesses of well, barrier and cap. These structural properties significantly affect different properties. For example, these properties affect electric fields of layers, polarization, overall elastic stress energy and lattice parameter of the structure, emission wavelength, and intensity of the emitted light. Three models with different composition and layer thicknesses are simulated and analyzed to obtain green light with in-plane equilibrium lattice parameter close to GaN （3.189 A ） with the highest oscillator strength values. A structure model is obtained with an oscillator strength value of 1.18 × 10-1 and least in-plane equilibrium lattice constant of 3.218 A. This emitter can emit at a wavelength of 540 nm, which is the expected design for the fabrication of highly efficient, bright green LEDs.

关键词： green light emitting diode (LED) latticeparameter oscillator strength InGaN quantum well (QW),A1GaN capping layer

Quasi-inverse Pendulum Model of 12 DoF Bipedal Walking

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2017年第2期14卷 179-190页

作者： M. Akhtaruzzaman Amir A. Shafie md. Raisuddin khan Department of Mechatronics Engineering Kulliyyah of Engineering International Islamic University Malaysia Kuala Lumpur 53100 Malaysia

This paper presents modeling of a 12-degree of freedom （DoF） bipedal robot, focusing on the lower limbs of the system, and trajectory design for walking on straight path. Gait trajectories are designed by modeling of center of mass （CoM） trajectory and swing foot ankle trajectory based on stance foot ankle. The dynamic equations of motion of the bipedal robot are derived by considering the system as a quasi inverted pendulmn （QIP） model. The direction and acceleration of CoM movement of the QIP model is determined by the position of CoM relative to the centre of pressure （COP）. To determine heel-contact and toe-off, two custom designed switches are attached with heel and toe positions of each foot. Four force sensitive resistor （FSR） sensors are also placed at the plantar surface to measure pressure that is induced on each foot while walking which leads to the calculation of CoP trajectory. The paper also describes forward kinematic （FIK） and inverse kinematic （IK） investigations of the biped model where Denavit-Hartenberg （D-H） representation and Geometric-Trigonometric （G-T） formulation approach are applied. Experiments are carried out to ensure the reliability of the proposed model where the links of the bipedal system follow the best possible trajectories while walking on straight path.

关键词： Humanoid robot quasi-inverse pendulum gait trajectory planning Anthropoid.

Options and Opportunities for Energy Management in Malaysian Grid Systems-Putrajaya as a Case Study

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2018年第4期16卷 316-324页

作者： Aravind CV Umashankar Subramaniam md.Shahrukh Adnan khan md. Ibrahim Ibne Alam School of Engineering Taylor’s University Subang Jaya 47500 Malaysia Department of Energy and Power Electronics VIT University Vellore 632014 India University of Asia Pacific Dhaka 1205 Bangladesh

This paper presents an opportunity for energy management with an integrated photovoltaic and wind farm for the energy and economic aspects of the commercial area located in Putrajaya. The energy economy accession conforming to the wind speed, temperature, solar irradiation, and energy consumption on a daily basis is taken into consideration. Design analysis is done through the industry standard numerical tool. From the result analysis, the recommended ratio of renewable share minimizing stress to the electric grid is proposed. According to the solutions obtained from the numerical design tool, photovoltaic is recommended to be more energy efficient and economically viable in comparison of the fully crowded wind farm. From the proposed solutions, the photovoltaic is able to provide 51% of the energy consumed and it costs RM 0.365 per kW/h.

关键词： Cost grid Homer Pro photovoltaic park wind turbine farm

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

在线全文

学校读者我要写书评

暂无评论

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

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

在线全文

学校读者我要写书评

暂无评论

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

Infrared Spectroscopic Analysis of Chrysene and 1.2-Benzanthracence in Wax films

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2006年第9期23卷 2407-2410页

作者： md. Naziruddin khan A. S. AI-Dwayyan Z. H. Zaidi Department of Applied Sciences A1-Falah School of Engineering and Technology Dhauj Faridabad-Haryana-121004 India Department of Physics College of Science King Saud University Riyadh KSA Department of Physics Jamia Millia Islamia New Delhi-25 India

Chrysene and 1.2-benzanthracene are successfully doped in a solid wax film and their vibrational spectra in gooo--400cm^-1 are discussed. The harmonic frequencies and relative intensities of both the molecules observed in the film are compared with theoretical values calculated by the density functional theory （DFT） model as well as with the previous experimental data. The effects on spectra due to change of matrix and some additional bands observed in the wax film are also reported. Excellent agreement in the spectral positions and strengths between the experiments and DFT values are found.

关键词： POLYCYCLIC AROMATIC-HYDROCARBONS EMISSION SPECTRA MOLECULES NAPHTHALENE HYPOTHESIS EXCITATION CATIONS BANDS

Design of a Simple Integrated Coupler for SPP Excitation in a Dielectric Coated Ag Thin Film

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第6期31卷 94-97页

作者： Rakibul Hasan Sagor md. Ruhul Amin md. Ghulam Saber Department of Electrical and Electronic Engineering Islamic University of Technology Board Bazar Gazipur-1704 Bangladesh

A simple integrated coupler is proposed for the efficient excitation of surface plasmon polariton （SPP） mode in a thin metal film. The SPP mode is generated in a single Ag-dielectric interface by the incident field and coupled with an Ag thin film. The coupling efficiency at different wavelengths using two different dielectrics, gallium lanthanum sulfide （GLS） and aluminum gallium arsenide （AIGaAs） is calculated by analyzing the SPP propagation dynamics with the finite difference time domain method. A maximum coupling efficiency of 70~ is obtained at a wavelength of 46Ohm when GLS is used, whereas the corresponding value obtained for A1GaAs is 60~o at 56Onto. The proposed structure can be used to excite SPPs in a nano-thin film from an external bulky source and is easier to fabricate since a single interface metal-dielectric configuration is used to excite the metal-thin film.

关键词： Efficiency

Addressing Frequency Control Challenges in Future Low-Inertia Power Systems:A Great Britain Perspective

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2021年第8期7卷 1057-1063页

作者： Qiteng Hong md.asif Uddin khan Callum Henderson AgustíEgea-Àlvarez Dimitrios Tzelepis Campbell Booth Department of Electronic and Electrical Engineering University of StrathclydeGlasgow G11XWUK

The ambitious global targets on decarbonization present the need for massive integration of renewable generation in power systems,resulting in a significant decrease in the system *** addition to the reduction in system inertia,the transmission system in Great Britain(GB)faces some unique challenges owing to its relatively small capacity,while being decoupled from other transmission systems and with the renewable resources largely non-uniformly distributed across the *** paper presents opinions and insights on the challenges associated with frequency control in a low-inertia system and the potential solutions from a GB *** this paper,we focus on three main techniques that act over different time scales:synchronous condensers,inertia emulation,and fast frequency *** evaluate their relative advantages and limitations with learnings from recent research and development projects in GB,along with the opinions on their roles in addressing the frequency control challenges in future low-inertia systems.

关键词： Fast frequency control Inertia emulation Synchronous compensation Low-inertia systems