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Evaluation of the Thermodynamic Performance of the Traditional Passive Systems
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作者 Antonio De Vecchi Simona Colajanni +2 位作者 Annalisa Lanza Volpe Miriam Noto Annalisa Palermo 《Journal of Energy and Power Engineering》 2013年第5期850-857,共8页
The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption th... The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD (computational fluid dynamic) software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort. 展开更多
关键词 BUILDING CFD simulation passive systems energy saving.
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Analysis of SBLOCA on CPR1000 with a passive system
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作者 Zi-Jiang Yang Jun-Li Gou +1 位作者 Jian-Qiang Shan Pan Wu 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第1期64-73,共10页
Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper p... Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ reactor.The passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety systems.When the SBLOCA occurred,the RMTs were initiated.The water in the RMTs was then injected into the pressure vessel.The RMTs' low water level triggered the PDS,which depressurized the coolant system drastically.As the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the core.The results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant. 展开更多
关键词 passive SAFETY systemS RELAP5/MOD3.3 CPR1000 SBLOCA
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Low-energy-consumption temperature swing system for CO_(2) capture by combining passive radiative cooling and solar heating 被引量:1
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作者 Ying-Xi Dang Peng Tan +3 位作者 Bin Hu Chen Gu Xiao-Qin Liu Lin-Bing Sun 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第3期507-515,共9页
Temperature-swing adsorption(TSA)is an effective technique for CO_(2) capture,but the temperature swing procedure is energy-intensive.Herein,we report a low-energy-consumption system by combining passive radiative coo... Temperature-swing adsorption(TSA)is an effective technique for CO_(2) capture,but the temperature swing procedure is energy-intensive.Herein,we report a low-energy-consumption system by combining passive radiative cooling and solar heating for the uptake of CO_(2) on commercial activated carbons(CACs).During adsorption,the adsorbents are coated with a layer of hierarchically porous poly(vinylidene fluoride-co-hexafluoropropene)[P(VdF-HFP)HP],which cools the adsorbents to a low temperature under sunlight through radiative cooling.For desorption,CACs with broad absorption of the solar spectrum are exposed to light irradiation for heating.The heating and cooling processes are completely driven by solar energy.Adsorption tests under mimicked sunlight using the CACs show that the performance of this system is comparable to that of the traditional ones.Furthermore,under real sunlight irradiation,the adsorption capacity of the CACs can be well maintained after multiple cycles.The present work may inspire the development of new temperature swing procedures with little energy consumption. 展开更多
关键词 CO_(2)capture Solar heating passive radiative cooling Temperature swing adsorption
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Task-Oriented Topology System Synthesis of Reconfigurable Legged Mobile Lander Integrating Active and Passive Metamorphoses
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作者 Youcheng Han Ziyue Li +3 位作者 Gaohan Zhu Weizhong Guo Jianzhong Yang Wei Liu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第3期89-109,共21页
To explore hostile extraterrestrial landforms and construct an engineering prototype,this paper presents the task-oriented topology system synthesis of reconfigurable legged mobile lander(ReLML)with three operation mo... To explore hostile extraterrestrial landforms and construct an engineering prototype,this paper presents the task-oriented topology system synthesis of reconfigurable legged mobile lander(ReLML)with three operation modes from adjusting,landing,to roving.Compared with our preceding works,the adjusting mode with three rotations(3R)provides a totally novel exploration approach to geometrically matching and securely arriving at complex terrains dangerous to visit currently;the landing mode is redefined by two rotations one translation(2R1T),identical with the tried-and-tested Apollo and Chang'E landers to enhance survivability via reasonable touchdown buffering motion;roving mode also utilizes 2R1T motion for good motion and force properties.The reconfigurable mechanism theory is first brought into synthesizing legged mobile lander integrating active and passive metamorphoses,composed of two types of metamorphic joints and metamorphic execution and transmission mechanisms.To reveal metamorphic principles with multiple finite motions,the finite screw theory is developed to present the procedure from unified mathematical representation,modes and source phase derivations,metamorphic joint and limb design,to final structure assembly.To identify the prototype topology,the 3D optimal selection matrix method is proposed considering three operation modes,five evaluation criteria,and two topological subsystems.Finally,simulation verifies the whole task implementation process to ensure the reasonability of design. 展开更多
关键词 Legged mobile lander Topology synthesis Active and passive metamorphoses Finite screw Metamorphic joint Reconfigurable mechanism
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Single exposure passive three-dimensional information reconstruction based on an ordinary imaging system
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作者 窦申成 刘璠 +3 位作者 李虎 姚旭日 刘雪峰 翟光杰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期446-455,共10页
Existing three-dimensional(3D) imaging technologies have issues such as requiring active illumination, multiple exposures, or coding modulation. We propose a passive single 3D imaging method based on an ordinary imagi... Existing three-dimensional(3D) imaging technologies have issues such as requiring active illumination, multiple exposures, or coding modulation. We propose a passive single 3D imaging method based on an ordinary imaging system.Using the point spread function of the imaging system to realize the non-coding measurement on the target, the full-focus images and depth information of the 3D target can be extracted from a single two-dimensional(2D) image through the compressed sensing algorithm. Simulation and experiments show that this approach can complete passive 3D imaging based on an ordinary imaging system without any coding operations. This method can achieve millimeter-level vertical resolution under single exposure conditions and has the potential for real-time dynamic 3D imaging. It improves the efficiency of 3D information detection, reduces the complexity of the imaging system, and may be of considerable value to the field of computer vision and other related applications. 展开更多
关键词 passive three-dimensional imaging single exposure point spread function compressed sensing
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Analysis of a passive ankle exoskeleton for reduction of metabolic costs during walking
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作者 Luís Quinto Pedro Pinheiro +3 位作者 Sergio B.Goncalves Ivo Roupa Paula Simoes Miguel Tavares da Silva 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第7期62-68,共7页
Modern conflicts demand substantial physical and psychological exertion,often resulting in fatigue and diminished combat or operational readiness.Several exoskeletons have been developed recently to address these chal... Modern conflicts demand substantial physical and psychological exertion,often resulting in fatigue and diminished combat or operational readiness.Several exoskeletons have been developed recently to address these challenges,presenting various limitations that affect their operational or everyday usability.This article evaluates the performance of a dual-purpose passive ankle exoskeleton developed for the reduction of metabolic costs during walking,seeking to identify a force element that could be applied to the target population.Based on the 6-min walk test,twenty-nine subjects participated in the study using three different force elements.The results indicate that it is possible to reduce metabolic expenditure while using the developed exoskeleton.Additionally,the comfort and range of motion results verify the exoskeleton's suitability for use in uneven terrain and during extended periods.Nevertheless,the choice of the force element should be tailored to each user,and the control system should be adjustable to optimise the exoskeleton's performance. 展开更多
关键词 Ankle passive exoskeleton Metabolic cost reduction Dual-use exoskeleton GAIT BIOMECHANICS
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Foam rolling and stretching do not provide superior acute flexibility and stiffness improvements compared to any other warm-up intervention: A systematic review with meta-analysis
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作者 Konstantin Warneke Gerit Plöschberger +5 位作者 Lars H.Lohmann Eric Lichtenstein Daniel Jochum Stanislav D.Siegel Astrid Zech David G.Behm 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第4期509-520,共12页
Background:Acute improvement in range of motion(ROM)is a widely reported effect of stretching and foam rolling,which is commonly explained by changes in pain threshold and/or musculotendinous stiffness.Interestingly,t... Background:Acute improvement in range of motion(ROM)is a widely reported effect of stretching and foam rolling,which is commonly explained by changes in pain threshold and/or musculotendinous stiffness.Interestingly,these effects were also reported in response to various other active and passive interventions that induce responses such as enhanced muscle temperature.Therefore,we hypothesized that acute ROM enhancements could be induced by a wide variety of interventions other than stretching or foam rolling that promote an increase in muscle temperature.Methods:After a systematic search in PubMed,Web of Science,and SPORTDiscus databases,38 studies comparing the effects of stretching and foam rolling with several other interventions on ROM and passive properties were included.These studies had 1134 participants in total,and the data analysis resulted in 140 effect sizes(ESs).ES calculations were performed using robust variance estimation model with R-package.Results:Study quality of the included studies was classified as fair(PEDro score=4.58)with low to moderate certainty of evidence.Results showed no significant differences in ROM(ES=0.01,p=0.88),stiffness(ES=0.09,p=0.67),or passive peak torque(ES=-0.30,p=0.14)between stretching or foam rolling and the other identified activities.Funnel plots revealed no publication bias.Conclusion:Based on current literature,our results challenge the established view on stretching and foam rolling as a recommended component of warm-up programs.The lack of significant difference between interventions suggests there is no need to emphasize stretching or foam rolling to induce acute ROM,passive peak torque increases,or stiffness reductions. 展开更多
关键词 Range of motion passive properties Muscletendon unit Muscle tissue
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Limit state analysis of rigid retaining structures against seismically induced passive failure in heterogeneous soils
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作者 Jianfeng Zhou Changbing Qin 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期1095-1105,共11页
Soils are not necessarily uniform and may present linearly varied or layered characteristics,for example the backfilled soils behind rigid retaining walls.In the presence of large lateral thrust imposed by arch bridge... Soils are not necessarily uniform and may present linearly varied or layered characteristics,for example the backfilled soils behind rigid retaining walls.In the presence of large lateral thrust imposed by arch bridge,passive soil failure is possible.A reliable prediction of passive earth pressure for the design of such wall is challenging in complicated soil strata,when adopting the conventional limit analysis method.In order to overcome the challenge for generating a kinematically admissible velocity field and a statically allowable stress field,finite element method is incorporated into limit analysis,forming finiteelement upper-bound(FEUB)and finite-element lower-bound(FELB)methods.Pseudo-static,original and modified pseudo-dynamic approaches are adopted to represent seismic acceleration inputs.After generating feasible velocity and stress fields within discretized elements based on specific criteria,FEUB and FELB formulations of seismic passive earth pressure(coefficient K_(P))can be derived from work rate balance equation and stress equilibrium.Resorting to an interior point algorithm,optimal upper and lower bound solutions are obtained.The proposed FEUB and FELB procedures are well validated by limit equilibrium as well as lower-bound and kinematic analyses.Parametric studies are carried out to investigate the effects of influential factors on seismic K_(P).Notably,true solution of K_(P) is well estimated based on less than 5%difference between FEUB and FELB solutions under such complex scenarios. 展开更多
关键词 Retaining wall passive earth pressure EARTHQUAKES Finite-element limit-analysis methods
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Passive activity enhances residual control ability in patients with complete spinal cord injury
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作者 Yanqing Xiao Mingming Gao +6 位作者 Zejia He Jia Zheng Hongming Bai Jia-Sheng Rao Guiyun Song Wei Song Xiaoguang Li 《Neural Regeneration Research》 SCIE CAS 2025年第8期2337-2347,共11页
Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these... Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury. 展开更多
关键词 complete spinal cord injury cycle training epidural electrical stimulation motor training passive activity physiological state spinal cord circuit surface electromyography volitional control task
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Coarse-fine joint target parameter estimation method based on AN-RSC in OFDM passive radar
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作者 WANG Chujun WAN Xianrong +1 位作者 YI Jianxin CHENG Feng 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期339-349,共11页
In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to... In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation. 展开更多
关键词 passive radar orthogonal frequency division multiplexing(OFDM)signal atomic norm(AN) parameter estimation
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Detection of UAV Target Based on Continuous Radon Transform and Matched Filtering Process for Passive Bistatic Radar
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作者 Luo Zuo Yuefei Yan +6 位作者 Jun Wang Xin Sang Yan Wang Dongming Ge Lihao Ping Zhihai Wang Congsi Wang 《Journal of Beijing Institute of Technology》 EI CAS 2024年第1期9-18,共10页
Long-time integration technique is an effective way of improving target detection performance for unmanned aerial vehicle(UAV)in the passive bistatic radar(PBR),while range migration(RM)and Doppler frequency migration... Long-time integration technique is an effective way of improving target detection performance for unmanned aerial vehicle(UAV)in the passive bistatic radar(PBR),while range migration(RM)and Doppler frequency migration(DFM)may have a major effect due to the target maneuverability.This paper proposed an innovative long-time coherent integration approach,regarded as Continuous Radon-matched filtering process(CRMFP),for low-observable UAV target in passive bistatic radar.It not only mitigates the RM by collaborative research in range and velocity dimensions but also compensates the DFM and ensures the coherent integration through the matched filtering process(MFP).Numerical and real-life data following detailed analysis verify that the proposed method can overcome the Doppler mismatch influence and acquire comparable detection performance. 展开更多
关键词 passive bistatic radar unmanned aerial vehicle long-time coherent integration Radon-matched filtering process
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Equalization Reconstruction Algorithm Based on Reference Signal Frequency Domain Block Joint for DTMB-Based Passive Radar
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作者 Shuai Ma Zeqi Yang +2 位作者 Hua Zhang Yiheng Liu Xiaode Lyu 《Journal of Beijing Institute of Technology》 EI CAS 2024年第1期41-53,共13页
Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small... Channel equalization plays a pivotal role within the reconstruction phase of passive radar reference signals.In the context of reconstructing digital terrestrial multimedia broadcasting(DTMB)signals for low-slow-small(LSS)target detection,a novel frequency domain block joint equalization algorithm is presented in this article.From the DTMB signal frame structure and channel multipath transmission characteristics,this article adopts a unconventional approach where the delay and frame structure of each DTMB signal frame are reconfigured to create a circular convolution block,facilitating concurrent fast Fourier transform(FFT)calculations.Following equalization,an inverse fast Fourier transform(IFFT)-based joint output and subsequent data reordering are executed to finalize the equalization process for the DTMB signal.Simulation and measured data confirm that this algorithm outperforms conventional techniques by reducing signal errors rate and enhancing real-time processing.In passive radar LSS detection,it effectively suppresses multipath and noise through frequency domain equalization,reducing false alarms and improving the capabilities of weak target detection. 展开更多
关键词 passive radar frequency domain equalization reference signal reconstruction digital terrestrial multimedia broadcasting(DTMB)
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LFM Radar Source Passive Localization Algorithm Based on Range Migration
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作者 Dandan Li Deyi Wang Hao Huan 《Journal of Beijing Institute of Technology》 EI CAS 2024年第2期130-140,共11页
Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of kilometers.Subsequently,a sin... Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of kilometers.Subsequently,a single-satellite localization algorithm based on passive synthetic aper-ture(PSA)was introduced,enabling high-precision positioning.However,its estimation of azimuth and range distance is considerably affected by the residual frequency offset(RFO)of uncoopera-tive system transceivers.Furthermore,it requires data containing a satellite flying over the radia-tion source for RFO search.After estimating the RFO,an accurate estimation of azimuth and range distance can be carried out,which is difficult to achieve in practical situations.An LFM radar source passive localization algorithm based on range migration is proposed to address the dif-ficulty in estimating frequency offset.The algorithm first provides a rough estimate of the pulse repetition time(PRT).It processes intercepted signals through range compression,range interpola-tion,and polynomial fitting to obtain range migration observations.Subsequently,it uses the changing information of range migration and an accurate PRT to formulate a system of nonlinear equations,obtaining the emitter position and a more accurate PRT through a two-step localization algorithm.Frequency offset only induces a fixed offset in range migration,which does not affect the changing information.This algorithm can also achieve high-precision localization in squint scenar-ios.Finally,the effectiveness of this algorithm is verified through simulations. 展开更多
关键词 passive localization range migration residual frequency offset
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The Effects of Thickness and Location of PCMon the Building’s Passive Temperature-Control–A Numerical Study
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作者 Zhengrong Shi JieRen +1 位作者 Tao Zhang Yanming Shen 《Energy Engineering》 EI 2024年第3期681-702,共22页
Building energy consumption and building carbon emissions both account for more than 20%of their total national values in China.Building employing phase change material(PCM)for passive temperature control shows a prom... Building energy consumption and building carbon emissions both account for more than 20%of their total national values in China.Building employing phase change material(PCM)for passive temperature control shows a promising prospect in meeting the comfort demand and reducing energy consumption simultaneously.However,there is a lack of more detailed research on the interaction between the location and thickness of PCM and indoor natural convection,as well as indoor temperature distribution.In this study,the numerical model of a passive temperature-controlled building integrating the developed PCM module is established with the help of ANSYS.In which,the actual weather condition of Beijing city is set as the boundary conditions and the indoor natural convection is simulated with the consideration of radiation model.The effects of PCM’s thickness and location on the internal temperature field are analyzed and discussed.The results show that the room could maintain within the human comfort temperature range with the longest ratio of 94.10%and the shortest ratio of 51.04%as integrating PCM.In comparison,the value is only 26.70%without PCM.The room’s maximum temperature fluctuation can also be improved;it could be lowered by 64.4%compared to the normal condition.When the quantity of PCM is sufficient,further increasing the PCM amount results in a temperature fluctuation reduction of less than 0.1°C and does not increase the comfort time.Placing PCM on the wall induces an apparent variation in indoor temperature along the vertical direction.Conversely,placing PCM on the roof can lead to a heat transfer rate difference of up to seven times.The optimal placement of PCM depends on the difference between the environmental and phase change temperatures.If the difference is positive,placing PCM on the roof is more effective;conversely,the opposite holds.According to the results over the entire cycle,PCM application on vertical walls yields better performance.The significant difference in natural convection caused by the same thickness of PCM but different application positions,coupled with the influence of air movement on the melting and solidification of PCM,further impacts indoor temperature fluctuations and comfort.This study can provide guidance for the application location and thickness of PCM,especially for scenarios where temperature regulation is required at a specific time. 展开更多
关键词 Phase change materials passive temperature regulation numerical simulation temperature field
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Application of Presumptive Consent in Passive Euthanasia
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作者 ZHANG Guixiang 《The Journal of Human Rights》 2024年第3期662-682,共21页
In the criminological system, passive euthanasia is an act that meets the constitutive elements. We should discard the traditional view of distinguishing between acts and omissions, but use genuine consent or presumpt... In the criminological system, passive euthanasia is an act that meets the constitutive elements. We should discard the traditional view of distinguishing between acts and omissions, but use genuine consent or presumptive consent under the patient’s right to self-determination as the basis for its justification. In general, the patient’s genuine consent takes precedence, but in case of the unavail-ability of the patient’s genuine consent, his or her presumptive consent should be applied as a substitute. The judgment of presumptive con-sent should follow the subsequence, with the living will of the patient applied first and then the substitute decision-making. If the patient’s personal will cannot be inferred after exhausting all available possi-bilities, the principle of prioritizing the interests of life should prevail, and the ongoing life-sustaining medical care should not be interrupted or terminated. 展开更多
关键词 passive euthanasia presumptive consent genuine consent right to self-determination
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The Economic Demands on the Method of Founding a Passive Brick House on Foamed Glass Granulate
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作者 Marek Jašek 《Journal of Civil Engineering and Architecture》 2024年第5期218-222,共5页
The cost of acquisition of a passive house is a little higher than that of a conventional house.Proper design of a passive house should include not only thermal protection and stability of the construction,but it must... The cost of acquisition of a passive house is a little higher than that of a conventional house.Proper design of a passive house should include not only thermal protection and stability of the construction,but it must also take into account the price demands on each of the proposed structures and solution of details.The paper deals with the financial comparison of the traditional method of a foundation on the foundation strips of plain concrete and the modern method of founding a passive house as brick construction on the reinforced concrete slab base with a compact subsoil layer of thermal insulation in the form of granules of foamed glass. 展开更多
关键词 passive house financial comparison granules of foamed glass
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Observability of Airborne Passive Location System with Phase Difference Measurements 被引量:4
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作者 邓新蒲 王强 钟丹星 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第2期149-154,共6页
With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by ad... With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision. 展开更多
关键词 passive location phase difference OBSERVABILITY ACCURACY
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Application of unscented Kalman filter to novel terrain passive integrated navigation system 被引量:2
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作者 王其 徐晓苏 《Journal of Southeast University(English Edition)》 EI CAS 2007年第4期545-549,共5页
To improve the navigation accuracy of an autonomous underwater vehicle (AUV), a novel terrain passive integrated navigation system (TPINS) is presented. According to the characteristics of the underwater environme... To improve the navigation accuracy of an autonomous underwater vehicle (AUV), a novel terrain passive integrated navigation system (TPINS) is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system (SINS), the terrain reference navigation system (TRNS), the Doppler velocity sonar (DVS), the magnetic compass and the navigation computer utilizing the unscented Kalman filter (UKF) to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter (EKF), nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation. 展开更多
关键词 autonomous underwater vehicle strapdown inertial navigation system unscented Kalman filter extended Kalman filter terrain passive integrated navigation system
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Novel gravity passive navigation system 被引量:10
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作者 蔡体菁 《Journal of Southeast University(English Edition)》 EI CAS 2006年第1期59-63,共5页
According to the characteristics of gravity passive navigation, this paper presents a novel gravity passive navigation system (GPNS), which consists of the rate azimuth platform (RAP), gravity sensor, digitally st... According to the characteristics of gravity passive navigation, this paper presents a novel gravity passive navigation system (GPNS), which consists of the rate azimuth platform (RAP), gravity sensor, digitally stored gravity maps, depth sensor and relative log. The algorithm of rate azimuth platform inertial navigation system, error state-space equations, measurement equations and GPNS optimal filter are described. In view of the measurements made by an onboard gravity sensor the Eotvos effect is introduced in the gravity measurement equation of a GPNS optimal filter. A GPNS is studied with the Matlab/Simulink tools; simulation results demonstrate that a GPNS has small errors in platform attitude and position. Because the inertial navigation platform is the rate azimuth platform in the GPNS and gravity sensor is mounted on the rate azimuth platform, the cost of the GPNS is lower than existing GPNS's and according to the above results the GPNS meets the need to maintain accuracy navigation for underwater vehicles over long intervals. 展开更多
关键词 gravity passive navigation system rate azimuth platform GRAVIMETER gravity map
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Passive control of Permanent Magnet Synchronous Motor chaotic systems 被引量:1
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作者 齐冬莲 王家军 赵光宙 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第7期728-732,共5页
Permanent Magnet Synchronous Motor model can exhibit a variety of chaotic phenomena under some choices of system parameters and external input. Based on the property of passive system, the essential conditions were st... Permanent Magnet Synchronous Motor model can exhibit a variety of chaotic phenomena under some choices of system parameters and external input. Based on the property of passive system, the essential conditions were studied, by which Permanent Magnet Synchronous Motor chaotic system could be equivalent to passive system. Using Lyapunov stability theory, the convergence condition deciding the system's characters was discussed. In the convergence condition area, the equivalent passive system could be globally asymptotically stabilized by smooth state feedback. 展开更多
关键词 Permanent Magnet Synchronous Motor passive system Convergence condition
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