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performance of pulsed plasma thruster at low discharge energy

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Plasma Science and Technology 2024年第4期26卷 122-132页

作者：李鸿俊林泽豪胡浩俊吴文东陈爱虹杜德扬 Department of Physics Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Faculty of Engineering The University of Nottingham Malaysia CampusSemenyih 43500Malaysia Faculty of Engineering Multimedia UniversityCyberjaya 63100Malaysia

As the size of satellites scales down, low-power and compact propulsion systems such as the pulsed plasma thruster(PPT) are needed for stabilizing these miniature satellites in orbit. Most PPT systems are operated at 2 J or more of discharge energy. In this work, the performance of a PPT with a side-fed, tongue-flared electrode configuration operated within a lower discharge energy range of 0.5-2.5 J has been investigated. Ablation and charring of the polytetrafluoroethylene propellant surface were analyzed through field-effect scanning electron microscopy imaging and energy-dispersive X-ray spectroscopy. When the discharge energy fell below 2 J, inconsistencies occurred in the specific impulse and the thrust efficiency due to the measurement of the low mass bit. At energy ≥2 J, the performance parameters are compared with other PPT systems of similar configuration and discussed in depth.

关键词： pulsed plasma thruster low discharge energy performance parameters

Development of Efficient Classification Systems for the Diagnosis of Melanoma

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Computer Systems Science & Engineering 2022年第7期42卷 361-371页

作者： S.Palpandi T.Meeradevi Department of Computer Science and Engineering Shri Andal Alagar College of EngineeringChengalpet603111Tamil NaduIndia Department of Electronics and Communication Engineering Kongu Engineering CollegePerundurai638060ErodeTamil NaduIndia

Skin cancer is usually classiﬁed as melanoma and *** now represents 75%of humans passing away worldwide and is one of the most brutal types of ***,studies were not mainly focused on feature extraction of Melanoma,which caused the classiﬁcation ***,in this work,Histograms of orientation gradients and local binary pat-terns feature extraction procedures are used to extract the important features such as asymmetry,symmetry,boundary irregularity,color,diameter,etc.,and are removed from both melanoma and non-melanoma *** proposed Efﬁ-cient Classiﬁcation Systems for the Diagnosis of Melanoma(ECSDM)framework consists of different schemes such as preprocessing,segmentation,feature extrac-tion,and classiﬁ*** used Machine Learning(ML)and Deep Learning(DL)classiﬁers in the classiﬁcation *** ML classiﬁer is Naïve Bayes(NB)and Support Vector Machines(SVM).And also,DL classiﬁcation frame-work of the Convolution Neural Network(CNN)is used to classify the melanoma and benign *** results show that the Neural Network(NNET)classiﬁer’achieves 97.17%of accuracy when contrasting with ML classiﬁers.

关键词： Melanoma benign classiﬁcation systems performance parameters

Energy and Life Cycle Assessment of Zinc/Water Nanofluid Based Photovoltaic Thermal System

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Energy Engineering 2022年第2期119卷 827-846页

作者： Junaid Khan Rashid Ali Muzammil Zubair Syed Mohd Yahya SEARL Laboratory Department of Mechancial EngineeringAligarh Muslim UniversityAligarh202002India

Cooling the PV surface in a Photovoltaic Thermal system is a pivotal operational aspect to be taken into account to achieve optimized values of performance parameters in a Photovoltaic Thermal *** experimental design used in this study facilitates the flow of varying concentrations of Zn-water nanofluid in serpentine copper tubing installed at the rear of the PV panel thereby preventing the PV surface temperature from increasing beyond the threshold value at which a decrease in electrical efficiency starts to *** fusion of solar thermal with PV devices leads to better electrical and thermal efficiency values resulting in decreased cell degradation over time and maximization of the lifespan of the PV module and the energy output from the PV *** to the superior thermal heat properties of nanofluids,their usage in such systems has become increasingly *** cycle metrics which include Energy Payback period,Energy Production Factor and life cycle conversion efficiency were evaluated for the PVT system by exhaustively chalking fundamental parameters such as embodied energy of the PVT setup and the total energy output from the PVT *** research aims to be a major milestone in the evolutionary journey of Photovoltaic Thermal modules by guiding the engineers working on the theory,design and implementation of PVT systems towards its economic feasibility,environmental impact and energy sustainability.

关键词： Photovoltaic thermal system nanofluids performance parameters life cycle assessment

Energy, economic and environmental performance assessment of a grid-tied rooftop system in different cities of India based on 3E analysis

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Clean Energy 2021年第2期5卷 288-301页

作者： Anupama Khare Saxena Seema Saxena KSudhakar Department of Electrical and Electronics Engineering Rajiv Gandhi Proudyogiki Vishwavidyalaya(RGPV)Bhopal462036India Energy Centre Maulana Azad National Institute of TechnologyBhopal462003India Faculty of Mechanical and Automotive Engineering Technology Universiti Malaysia Pahang26600Malaysia

India is very rich in solar energy,with a total of 3000 sunshine hours annually in most *** installation of on-grid rooftop electricity-generation photovoltaic(PV)systems is currently undergoing substantial growth and extension as an alternate source of energy that contributes to Indian *** paper analyses the viability of mounting solar PV plants in distinct cities of India in various locations with different climate conditions such as Delhi,Bhopal,Udaipur,Ahmadabad,Thiruvananthapuram,Pune and *** technical feasibility of installing a 100-kWp system is evaluated using PVsyst software under local climatic *** performance ratio is between 70%and 80%,with a capacity utilization factor of 19-21%and estimated energy output of 170 MWh annually at all *** system produces 400-500 kWh of energy daily at a per-unit cost of INR 6-7(Indian rupees)in all *** lifespan of the system is~25-30 years,reducing about 150-170 tons of carbon-dioxide emission to the atmosphere every *** payback period of the system is~5-6 years,which defines its *** information would encourage organizations and individuals to install such PV plants on the rooftops of buildings to use solar electricity for meeting the energy demands of the country.

关键词： technical analysis solar photovoltaic system plant feasibility grid-connected system performance parameters

Measuring the spatial quality of bedrooms in nursing homes with visual environmental performance

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Frontiers of Architectural Research 2021年第2期10卷 332-350页

作者： Dake Wei Xi Li School of Architecture Harbin Institute of TechnologyHarbin 150006China Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology(Ministry of Industry and Information Technology) Horbin 150006China

The elderly's perception of their environment largely depends on acquired visual *** study provides a quantitative analytical method for designing bedrooms in nursing homes by developing a computational model that uses viewing distance,viewing angle,and viewing field as *** model is utilized to measure a range of visual environmental properties,including privacy,accessibility,permeability,and visibility,which reflect the quality of bedrooms in nursing *** suitability levels of bedroom planes for the elderly and their main living functions as well as the fitting degree of the functional layout are calculated based on these *** validating the computational moders feasibility,this study optimizes the typical schemes of single and double rooms in nursing *** reveal certain advantages of the arrangement where bathroom doors are set toward the inside of the bedroom and double rooms have a large *** computational model can be used in measuring the spatial quality of bedrooms in nursing homes and as a mathematical model for related algorithm design and software programming to assist in the design and optimization of bedrooms for the elderly.

关键词： Nursing home Elderly bedroom Spatial quality Visual environment Computational model performance parameters

performance of an irreversible quantum refrigeration cycle

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Chinese Physics B 2006年第1期15卷 53-59页

作者：何济洲欧阳微频伍歆 Department of Physics Nanchang University Nanchang 330047 China

A new model of a quantum refrigeration cycle composed of two adiabatic and two isomagnetic field processes is established. The working substance in the cycle consists of many non-interacting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semi-group approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. It is found that the coefficient of performance of this cycle is in the closest analogy to that of the classical Carnot cycle. Furthermore, at high temperatures the optimal relations of the cooling rate and the maximum cooling rate are analysed in detail. Some performance characteristic curves of the cycle are plotted, such as the cooling rate versus the maximum ratio between high and low ＂temperatures＂ of the working substances, the maximum cooling rate versus the ratio between high and low ＂magnetic fields＂ and the ＂temperature＂ ratio between high and low reservoirs. The obtained results are further generalized and discussed, so that they may be directly applied to describing the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot and Ericsson refrigeration cycles are derived by analogy.

关键词： spin systems quantum refrigeration cycle performance parameters

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液氧煤油发动机混合比调整技术研究

Aerospace China 2023年第2期24卷 39-45页

作者： YANG Yongqiang CAO Chen MA Nan WANG Fei Xi'an Aerospace Propulsion Institute Xi'an 710100 Science and Technology on Liquid Rocket Engine Laboratory Xi'an 710100

The LM-5B carrier rocket’s first stage is equipped with eight 120 *** high-pressure staged combustion LOX/kerosene engines(YF-100).The YF-100 engine features a throttle valve in the main fuel path,which allows the adjustment of the throttle area,thereby controlling the engine’s mixture *** parameters for the throttle valve were determined based on design conditions(mixture ratio of 2.6),and the engine was then tested for *** testing,if the mixture ratio was found not to meet the overall requirements of the rocket,the throttle area could be adjusted prior to subsequent ignition or installation in the whole system,enabling a secondary adjustment of the mixture *** paper outlines the methodology for static parameter calculations of the engine and the analysis of internal and external interference factors,and presents a scheme for the secondary adjustment of the engine’s mixture ratio and examines the precision of this secondary *** mixture ratio adjustment technology can notably reduce the dispersion range of mixture ratios for YF-100 ***,the influence of mixture ratio adjustment on engine performance parameters was *** approach of mixture ratio adjustment proposed in this paper lays the technical foundation for the precise adjustment of mixture ratio for future heavy-lift rocket engines.

关键词： LM-5B LOX/kerosene engine mixture ratio adjustment performance parameters

An overview of resistive random access memory devices

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Science Bulletin 2011年第Z2期 3072-3078页

作者： LI YingTao 1,2 , LONG ShiBing 2 , LIU Qi 2 , Lü HangBing 2 , LIU Su 1 & LIU Ming 2* 1 School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China 2 Laboratory of Nano-Fabrication and Novel Device Integration, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China

With recent progress in material science, resistive random access memory (RRAM) devices have attracted interest for nonvolatile, low-power, nondestructive readout, and high-density memories. Relevant performance parameters of RRAM devices include operating voltage, operation speed, resistance ratio, endurance, retention time, device yield, and multilevel storage. Numerous resistive-switching mechanisms, such as conductive filament, space-charge-limited conduction, trap charging and discharging, Schottky Emission, and Pool-Frenkel emission, have been proposed to explain the resistive switching of RRAM devices. In addition to a discussion of these mechanisms, the effects of electrode materials, doped oxide materials, and different configuration devices on the resistive-switching characteristics in nonvolatile memory applications, are reviewed. Finally, suggestions for future research, as well as the challenges awaiting RRAM devices, are given.

关键词： resistive random access memory resistive switching performance parameters

A Design of PDT Radiation Chamber Based on High Power LED

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A Design of PDT Radiation Chamber Based on High Power LED