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Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries 被引量:2
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作者 M.Grandin H.K.Connor +5 位作者 S.Hoilijoki M.Battarbee Y.Pfau-Kempf U.Ganse K.Papadakis M.Palmroth 《Earth and Planetary Physics》 EI CSCD 2024年第1期70-88,共19页
Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing tech... Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing techniques.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)and Lunar Environment heliospheric X-ray Imager(LEXI)missions aim to obtain soft Xray images of near-Earth space thanks to their Soft X-ray Imager(SXI)instruments.While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission,the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft Xray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model.The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field.We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views.We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the magnetopause.Our results suggest that,although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images.For instance,a local increase by 30%in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray emissivity originating from this region.Likewise,a proton density increase by 14%in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%.These are likely conservative estimates,given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind.These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale,transient phenomena occurring on the dayside. 展开更多
关键词 MAGNETOSPHERE MAGNETOSHEATH numerical simulation SMILE LEXI soft X-ray emissions hybrid-Vlasov model polar cusp flux transfer events mirror-mode waves
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Analysis of debris flow control effect and hazard assessment in Xinqiao Gully,Wenchuan M_(s)8.0 earthquake area based on numerical simulation
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作者 Chang Yang Yong-bo Tie +3 位作者 Xian-zheng Zhang Yan-feng Zhang Zhi-jie Ning Zong-liang Li 《China Geology》 CAS CSCD 2024年第2期248-263,共16页
Xinqiao Gully is located in the area of the 2008 Wenchuan M_(s)8.0 earthquake in Sichuan province,China.Based on the investigation of the 2023"6-26"Xinqiao Gully debris flow event,this study assessed the eff... Xinqiao Gully is located in the area of the 2008 Wenchuan M_(s)8.0 earthquake in Sichuan province,China.Based on the investigation of the 2023"6-26"Xinqiao Gully debris flow event,this study assessed the effectiveness of the debris flow control project and evaluated the debris flow hazards.Through field investigation and numerical simulation methods,the indicators of flow intensity reduction rate and storage capacity fullness were proposed to quantify the effectiveness of the engineering measures in the debris flow event.The simulation results show that the debris flow control project reduced the flow intensity by41.05%to 64.61%.The storage capacity of the dam decreases gradually from upstream to the mouth of the gully,thus effectively intercepting and controlling the debris flow.By evaluating the debris flow of different recurrence intervals,further measures are recommended for managing debris flow events. 展开更多
关键词 Landslide Debris flow Hazard assessment Numerical simulation OpenLISEM Prevention and control project Wenchuan M_(s)8.0 earthquake Xinqiao Gully Sichuan province Geological hazards survey engineering
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Preliminary Design, Drive-Cycle Simulation and Energy Analysis of a Hybrid Transit Bus
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作者 Roberto Capata 《Journal of Energy and Power Engineering》 2019年第6期209-228,共20页
Modern metropolises are increasingly affected by air quality problems. Transportation is one of the largest sources of several pollutants emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). Today in the... Modern metropolises are increasingly affected by air quality problems. Transportation is one of the largest sources of several pollutants emissions, such as nitrogen oxides (NOx) and carbon monoxide (CO). Today in the EU, vehicles' emissions are strictly limited by Euro 6 norm-Euro VI for heavy-duty vehicles-which is periodically upgraded. To match such limits, manufacturers are forced in developing new technologies to perform new sustainable vehicles design strategies, such as EVs and HEVs. Present work's aim is to provide the design of series-hybrid urban transportation bus, equipped with a novel thermal power unit, namely a small gas turbine, to exploit its cleaner combustion process in comparison with an ICE. The control logic is described, while the main drivetrain components are chosen, and suitable models from suppliers are selected as well. Then, some simulations of the resulting vehicle are performed on opportune drive cycles, using Advisor, a free software based on Matlab-Simulink environment, published by US' National Renewable Energy Laboratory (NREL). Two different final configurations are environmentally and economically analysed, with the thermal power unit being respectively fuelled by compressed natural gas (CNG) and liquefied petroleum gas (LPG). Both satisfy the Euro VI norms, showing a substantial emission reduction (-89% and -43% in CO and THC releases respectively) in comparison to pollutants' threshold values. 展开更多
关键词 HEV GTHV heavy-duty bus ADVISOR MICROTURBINE (MT) gas turbine (GT) CNG LPG simulation DRIVE CYCLE Euro VI WHTC emissions NOx CO THC sustainability pollution
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Geant4 simulation of fast-electron bremsstrahlung imaging at the HL-3 tokamak
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作者 Shi-Kui Cheng Yi-Po Zhang +4 位作者 Yue-Jiang Shi Jie Zhang Shuai Guan Hong-Bing Xu Qiu-Lei Yang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第9期213-229,共17页
To further research on high-parameter plasma,we plan to develop a two-dimensional hard X-ray(HXR)imaging system at the HL-3 tokamak to measure HXRs with energies ranging from 20 to 300 keV.The application of an array-... To further research on high-parameter plasma,we plan to develop a two-dimensional hard X-ray(HXR)imaging system at the HL-3 tokamak to measure HXRs with energies ranging from 20 to 300 keV.The application of an array-structured detector ensures that this system can measure HXR-radiation spectra from the entire plasma cross section.Therefore,it is suitable for the study of fast-electron physics,such as radio-frequency wave current drives,fast electrons driving instabilities,and plasma disruptions in fusion research.In this study,we develop a simulation for calculating fast-electron bremsstrahlung in the HL-3 tokamak based on the Monte Carlo simulation code Geant4,in which the plasma geometry and forward scattering of fast-electron bremsstrahlung are considered.The preliminary calculation results indicate that the HXR energy deposi-tion on the detector is symmetrically distributed,even though the plasma distribution is asymmetric owing to the toroidal effect.These simulation results are helpful in constructing the relationship between the energy deposition on the detector and parameter distribution on the plasma cross section during HL-3 experiments.This is beneficial for the reconstruction of the fast-electron-distribution function and for optimizing the design of the HXR-imaging system. 展开更多
关键词 GEANT4 simulation HL-3 TOKAMAK Fast-electron bremsstrahlung Hard X-ray imaging
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Simulation Modelling and Techno-Economics of Supercritical Carbon Dioxide Recompression Closed Brayton Cycle
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作者 Ken Amaale Atinga 《Energy and Power Engineering》 2024年第10期325-344,共20页
In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential inve... In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant. 展开更多
关键词 Supercritical Carbon Dioxide (sCO2) Closed Brayton Cycle TECHNO-ECONOMICS simulation Capital Expenditure Gas Turbine THERMODYNAMIC Equipment Cost Optimization and Sensitivity
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Dynamic simulation insights into friction weakening effect on rapid long-runout landslides:A case study of the Yigong landslide in the Tibetan Plateau,China
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作者 Zi-zheng Guo Xin-yong Zhou +3 位作者 Da Huang Shi-jie Zhai Bi-xia Tian Guang-ming Li 《China Geology》 CAS CSCD 2024年第2期222-236,共15页
This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plate... This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plateau of China was employed as the case,and the derived dynamic friction formula was included into the numerical simulation based on Particle Flow Code.Results showed that the friction decreased quickly from 0.64(the peak)to 0.1(the stead value)during the 5s-period after the sliding initiation,which explained the behavior of rapid movement of the landslide.The monitored balls set at different sections of the mass showed similar variation characteritics regarding the velocity,namely evident increase at the initial phase of the movement,followed by a fluctuation phase and then a stopping one.The peak velocity was more than 100 m/s and most particles had low velocities at 300s after the landslide initiation.The spreading distance of the landslide was calculated at the two-dimension(profile)and three-dimension scale,respectively.Compared with the simulation result without considering friction weakening effect,our results indicated a max distance of about 10 km from the initial unstable position,which fit better with the actual situation. 展开更多
关键词 Rapid long-runout landslide PFC Friction weakening Three-dimension Numerical simulation Tibetan Plateau Hydrogeology Engineering Geological hazards survey engineering
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AN INTEGRATION METHOD WITH FITTING CUBIC SPLINE FUNCTIONS TO A NUMERICAL MODEL OF 2ND-ORDER SPACE-TIME DIFFERENTIAL REMAINDER——FOR AN IDEAL GLOBAL SIMULATION CASE WITH PRIMITIVE ATMOSPHERIC EQUATIONS
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作者 辜旭赞 张兵 王明欢 《Journal of Tropical Meteorology》 SCIE 2013年第4期388-396,共9页
In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubi... In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation. 展开更多
关键词 NUMERICAL forecast and NUMERICAL simulation 2nd-order SPACE-TIME differential REMAINDER NUMERICAL model cubic spline functions Navier-Stokes PRIMITIVE EQUATIONS quasi-Lagrangian time-split integration scheme global simulation case
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A review of interaction mechanisms and microscopic simulation methods for CO_(2)-water-rock system
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作者 ZHANG Liehui ZHANG Tao +6 位作者 ZHAO Yulong HU Haoran WEN Shaomu WU Jianfa CAO Cheng WANG Yongchao FAN Yunting 《Petroleum Exploration and Development》 SCIE 2024年第1期223-238,共16页
This work systematically reviews the complex mechanisms of CO_(2)-water-rock interactions,microscopic simulations of reactive transport(dissolution,precipitation and precipitate migration)in porous media,and microscop... This work systematically reviews the complex mechanisms of CO_(2)-water-rock interactions,microscopic simulations of reactive transport(dissolution,precipitation and precipitate migration)in porous media,and microscopic simulations of CO_(2)-water-rock system.The work points out the key issues in current research and provides suggestions for future research.After injection of CO_(2) into underground reservoirs,not only conventional pressure-driven flow and mass transfer processes occur,but also special physicochemical phenomena like dissolution,precipitation,and precipitate migration.The coupling of these processes causes complex changes in permeability and porosity parameters of the porous media.Pore-scale microscopic flow simulations can provide detailed information within the three-dimensional pore and throat space and explicitly observe changes in the fluid-solid interfaces of porous media during reactions.At present,the research has limitations in the decoupling of complex mechanisms,characterization of differential multi-mineral reactions,precipitation generation mechanisms and characterization(crystal nucleation and mineral detachment),simulation methods for precipitation-fluid interaction,and coupling mechanisms of multiple physicochemical processes.In future studies,it is essential to innovate experimental methods to decouple“dissolution-precipitation-precipitate migration”processes,improve the accuracy of experimental testing of minerals geochemical reaction-related parameters,build reliable characterization of various precipitation types,establish precipitation-fluid interaction simulation methods,coordinate the boundary conditions of different physicochemical processes,and,finally,achieve coupled flow simulation of“dissolution-precipitation-precipitate migration”within CO_(2)-water-rock systems. 展开更多
关键词 CO_(2)-water-rock DISSOLUTION precipitation precipitate migration microscopic simulation CO_(2)capture utilization and storage carbon neutrality decouple
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Study on Operation of Arctic Offshore Complex by Means of Multicomponent Process-Based Simulation 被引量:1
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作者 Oleg V.Tarovik Alex Topaj +2 位作者 Andrey B.Krestyantsev Aleksander A.Kondratenko Dmitry A.Zaikin 《Journal of Marine Science and Application》 CSCD 2018年第4期471-497,共27页
We developed a detailed simulation model of the Arctic marine transport system(MTS) for oil platform Prirazlomnaya. The model has a multidisciplinary nature and involves: sub-models of various transport and technologi... We developed a detailed simulation model of the Arctic marine transport system(MTS) for oil platform Prirazlomnaya. The model has a multidisciplinary nature and involves: sub-models of various transport and technological processes; stochastic weather generator to obtain time series of 15 environmental parameters; and contextual planning algorithm to build voyage plan considering several types of ships and cargoes. We used a significant amount of real operational data to identify model parameters and to prove its statistical reliability. Our main scientific task is to investigate the interaction of various processes of a different nature, while the practical aim is to find a set of measures to increase the efficiency of MTS. The results of the study reveal many examples of the mutual interaction of various processes that need to be considered at the design stage to avoid technical mistakes.The study formed a basis for making managerial decisions at the top level of Gazprom Neft Shelf Company. 展开更多
关键词 Marine transport system Discrete event simulation OFFSHORE oil platform Stochastic weather generator Vessel VOYAGE planning Supply VESSELS operation ARCTIC tankers
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Increasing the Safety of People Activity in Aggressive Potential Locations, Analyzed through the Probability Theory, Modeling/Simulation and Application in Underground Coal Mining
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作者 Emil Pop Gabriel-Ioan Ilcea +1 位作者 Ionut-Alin Popa Lorand Bogdanffy 《Engineering(科研)》 2019年第2期93-106,共14页
This paper deals with the increasing safety of working in aggressive potential locations, having SCADA system and WSN sensors, using a “probabilistic strategy” in comparison with a “deterministic” one, modeling/si... This paper deals with the increasing safety of working in aggressive potential locations, having SCADA system and WSN sensors, using a “probabilistic strategy” in comparison with a “deterministic” one, modeling/simulation and application in underground coal mining. In general, three conditions can be considered: 1) an unfriendly environment that facilitates the risk of accidents, 2) aggressive equipments that can compete to cause accidents and 3) the work security breaches that can cause accidents. These conditions define the triangle of accidents and are customized for an underground coal mining where the methane gas is released with the exploitation of the massive coal. In this case, the first two conditions create an explosive potential atmosphere. To allow people to work in a safe location it needs: first, a continuing monitoring through SCADA system of the explosive potential atmosphere and second, the use of antiexplosive equipment. This method, named “deterministic strategy”, increases the safety of working, but the explosions have not been completely eliminated. In order to increase the safety of working, the paper continues with the presentation of a new method based on hazard laws, named “probabilistic strategy”. This strategy was validated through modeling/simulation using CupCarbon software platform, and application of WSN networks implemented on Arduino equipments. At the end of the paper the interesting conclusions are emphases which are applicable to both strategies. 展开更多
关键词 Accident Potentially SAFETY Zone TRIANGLE of Accidents Hazard LAWS Deterministic STRATEGY Probabilistic STRATEGY CupCarbon Modeling and simulation WSN Applications Arduino Implementation Example
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Kinetic simulation of hydrocarbon generation and its application to in-situ conversion of shale oil
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作者 ZHANG Bin YU Cong +3 位作者 CUI Jingwei MI Jingkui LI Huadong HE Fei 《Petroleum Exploration and Development》 2019年第6期1288-1296,共9页
The kinetic parameters of hydrocarbon generation are determined through experimental simulation and mathematical calculation using four typical samples selected from the Cretaceous Nenjiang Formation in the northwest ... The kinetic parameters of hydrocarbon generation are determined through experimental simulation and mathematical calculation using four typical samples selected from the Cretaceous Nenjiang Formation in the northwest of Songliao Basin,Chang 7 Member of Triassic Yanchang Formation in the southwest of Ordos Basin,Paleogene in the southwest of Qaidam Basin,and Lucaogou Formation of Jimusar Sag in the east of Junggar Basin.The results show that activation energy of hydrocarbon generation of organic matter is closely related to maturity and mainly ranges between 197 kJ/mol and 227 kJ/mol.On this basis,the temperature required for organic matter in shale to convert into oil was calculated.The ideal heating temperature is between 270℃and 300℃,and the conversation rate can reach 90%after 50-300 days of heating at constant temperature.When the temperature rises at a constant rate,the temperature corresponding to the major hydrocarbon generation period ranges from 225 to 350℃at the temperature rise rate of 1-150℃/month.In order to obtain higher economic benefits,it is suggested to adopt higher temperature rise rate(60-150℃/month).The more reliable kinetic parameters obtained can provide a basis for designing more reasonable scheme of in-situ heating conversion. 展开更多
关键词 HYDROCARBON GENERATION kinetics shale oil activation energy IN-SITU CONVERSION Permian Lucaogou FORMATION Triassic Yanchang FORMATION Chang 7 Member Cretaceous Nenjiang FORMATION HYDROCARBON GENERATION simulation
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Spatiotemporal evolution and future simulation of land use/land cover in the Turpan-Hami Basin,China
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作者 CHEN Yiyang ZHANG Li +4 位作者 YAN Min WU Yin DONG Yuqi SHAO Wei ZHANG Qinglan 《Journal of Arid Land》 SCIE CSCD 2024年第10期1303-1326,共24页
The Turpan-Hami(Tuha)Basin in Xinjiang Uygur Autonomous Region of China,holds significant strategic importance as a key economic artery of the ancient Silk Road and the Belt and Road Initiative,necessitating a holisti... The Turpan-Hami(Tuha)Basin in Xinjiang Uygur Autonomous Region of China,holds significant strategic importance as a key economic artery of the ancient Silk Road and the Belt and Road Initiative,necessitating a holistic understanding of the spatiotemporal evolution of land use/land cover(LULC)to foster sustainable planning that is tailored to the region's unique resource endowments.However,existing LULC classification methods demonstrate inadequate accuracy,hindering effective regional planning.In this study,we established a two-level LULC classification system(8 primary types and 22 secondary types)for the Tuha Basin.By employing Landsat 5/7/8 imagery at 5-a intervals,we developed the LULC dataset of the Tuha Basin from 1990 to 2020,conducted the accuracy assessment and spatiotemporal evolution analysis,and simulated the future LULC under various scenarios via the Markov-Future Land Use Simulation(Markov-FLUS)model.The results revealed that the average overall accuracy values of our LULC dataset were 0.917 and 0.864 for the primary types and secondary types,respectively.Compared with the seven mainstream LULC products(GlobeLand30,Global 30-meter Land Cover with Fine Classification System(GLC_FCS30),Finer Resolution Observation and Monitoring of Global Land Cover PLUS(FROM_GLC PLUS),ESA Global Land Cover(ESA_LC),Esri Land Cover(ESRI_LC),China Multi-Period Land Use Land Cover Change Remote Sensing Monitoring Dataset(CNLUCC),and China Annual Land Cover Dataset(CLCD))in 2020,our LULC data exhibited dramatically elevated overall accuracy and provided more precise delineations for land features,thereby yielding high-quality data backups for land resource analyses within the basin.In 2020,unused land(78.0%of the study area)and grassland(18.6%)were the dominant LULC types of the basin;although cropland and construction land constituted less than 1.0%of the total area,they played a vital role in arid land development and primarily situated within oases that form the urban cores of the cities of Turpan and Hami.Between 1990 and 2020,cropland and construction land exhibited a rapid expansion,and the total area of water body decreased yet resurging after 2015 due to an increase in areas of reservoir and pond.In future scenario simulations,significant increases in areas of construction land and cropland are anticipated under the business-as-usual scenario,whereas the wetland area will decrease,suggesting the need for ecological attention under this development pathway.In contrast,the economic development scenario underscores the fast-paced expansion of construction land,primarily from the conversion of unused land,highlighting the significant developmental potential of unused land with a slowing increase in cropland.Special attention should thus be directed toward ecological and cropland protection during development.This study provides data supports and policy recommendations for the sustainable development goals of Tuha Basin and other similar arid areas. 展开更多
关键词 land use/land cover(LULC) future simulation manual interpretation Markov-Future Land Use simulation(Markov-FLUS)model Turpan-Hami(Tuha)Basin XINJIANG
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Multi-scenario Simulation and Spatial-temporal Analysis of LUCC in China's Coastal Zone Based on Coupled SD-FLUS Model
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作者 HOU Xiyong SONG Baiyuan +2 位作者 ZHANG Xueying WANG Xiaoli LI Dong 《Chinese Geographical Science》 SCIE CSCD 2024年第4期579-598,共20页
Increased human activities in China's coastal zone have resulted in the depletion of ecological land resources.Thus,conducting current and future multi-scenario simulation research on land use and land cover chang... Increased human activities in China's coastal zone have resulted in the depletion of ecological land resources.Thus,conducting current and future multi-scenario simulation research on land use and land cover change(LUCC)is crucial for guiding the healthy and sustainable development of coastal zones.System dynamic(SD)-future land use simulation(FLUS)model,a coupled simulation model,was developed to analyze land use dynamics in China's coastal zone.This model encompasses five scenarios,namely,SSP1-RCP2.6(A),SSP2-RCP4.5(B),SSP3-RCP4.5(C),SSP4-RCP4.5(D),and SSP5-RCP8.5(E).The SD model simulates land use demand on an annual basis up to the year 2100.Subsequently,the FLUS model determines the spatial distribution of land use for the near term(2035),medium term(2050),and long term(2100).Results reveal a slowing trend in land use changes in China's coastal zone from 2000–2020.Among these changes,the expansion rate of construction land was the highest and exhibited an annual decrease.By 2100,land use predictions exhibit high accuracy,and notable differences are observed in trends across scenarios.In summary,the expansion of production,living,and ecological spaces toward the sea remains prominent.Scenario A emphasizes reduced land resource dependence,benefiting ecological land protection.Scenario B witnesses an intensified expansion of artificial wetlands.Scenario C sees substantial land needs for living and production,while Scenario D shows coastal forest and grassland shrinkage.Lastly,in Scenario E,the conflict between humans and land intensifies.This study presents pertinent recommendations for the future development,utilization,and management of coastal areas in China.The research contributes valuable scientific support for informed,long-term strategic decision making within coastal regions. 展开更多
关键词 land use and land cover change(LUCC) multi-scenario simulation system dynamic-future land use simulation(SD-FLUS)model SSP-RCP scenarios model coupling China's coastal zone
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Chemical simulation teaching system based on virtual reality and gesture interaction
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作者 Dengzhen LU Hengyi LI +2 位作者 Boyu QIU Siyuan LIU Shuhan QI 《虚拟现实与智能硬件(中英文)》 EI 2024年第2期148-168,共21页
Background Most existing chemical experiment teaching systems lack solid immersive experiences,making it difficult to engage students.To address these challenges,we propose a chemical simulation teaching system based ... Background Most existing chemical experiment teaching systems lack solid immersive experiences,making it difficult to engage students.To address these challenges,we propose a chemical simulation teaching system based on virtual reality and gesture interaction.Methods The parameters of the models were obtained through actual investigation,whereby Blender and 3DS MAX were used to model and import these parameters into a physics engine.By establishing an interface for the physics engine,gesture interaction hardware,and virtual reality(VR)helmet,a highly realistic chemical experiment environment was created.Using code script logic,particle systems,as well as other systems,chemical phenomena were simulated.Furthermore,we created an online teaching platform using streaming media and databases to address the problems of distance teaching.Results The proposed system was evaluated against two mainstream products in the market.In the experiments,the proposed system outperformed the other products in terms of fidelity and practicality.Conclusions The proposed system which offers realistic simulations and practicability,can help improve the high school chemistry experimental education. 展开更多
关键词 Chemical experiment simulation Gesture interaction Virtual reality Model establishment Process control Streaming media DATABASE
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The Impact of Simulation Education on Self-Efficacy in Pre-Registration Nursing Students
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作者 Ahmed A. Hakami Aisha Hussin Rabie +2 位作者 Sultan Ghormallah M. Alzahrani Faisal Mohammed Alnakhilan Khalid Awaidhalharbi 《Open Journal of Nursing》 2024年第1期51-76,共26页
This literature review primarily aims to explore and synthesise the previous studies in simulation education research conducted over the past five years related to the effects of simulation training on the self-effica... This literature review primarily aims to explore and synthesise the previous studies in simulation education research conducted over the past five years related to the effects of simulation training on the self-efficacy of undergraduate pre-registration nursing students. The second aim of this study is to explore additional outcome variables that were examined in the previous studies. Five electronic databases were searched systematically. These databases were MEDLINE, CINAHL Plus, Scopus, Embase and PsycINFO. The PICO model was employed to identify the search terms, with a thesaurus being used to provide synonyms. Reference lists of relevant articles were examined and hand searches of journals were also undertaken. The quality of each study was assessed using the Simulation Research Rubric (SRR). A total of 11 studies were included. All studies explored the impact of simulation education on undergraduate pre-registration nursing. Six studies explored nursing students’ competence and performance and two papers examined their critical thinking. Problem solving, learning motivation, communication skills and knowledge acquisition were examined once. The majority of studies indicated that simulation training has a positive impact on pre-registration nursing students’ self-efficacy and other outcome variables. Furthermore, the study results indicate that simulation training is more dependable than traditional training, and students were extremely satisfied with the simulation training. However, most of the studies included in this review had several gaps, including study design, sample size and dissimilarities between the scales used. Further research with large samples, reliable and valid instruments, and outcomes measures (such as critical thinking and transferability of skills) is required to provide better insight into the effectiveness of simulation in undergraduate nursing education. . 展开更多
关键词 simulation Education SELF-EFFICACY Pre-Registration Nursing Students Clinical Skills Undergraduate Nursing Education Teaching Techniques DECISION-MAKING
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Exhaustive review of acceleration strategies for Monte Carlo simulations in photon transit 被引量:1
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作者 Louzhe Xu Zijie Zhu Ting Li 《Journal of Innovative Optical Health Sciences》 SCIE EI CSCD 2024年第5期5-21,共17页
Monte Carlo simulation techniques have become the quintessence and a pivotal nexus of inquiry in the realm of simulating photon movement within biological fabrics.Through the stochastic sampling of tissue archetypes d... Monte Carlo simulation techniques have become the quintessence and a pivotal nexus of inquiry in the realm of simulating photon movement within biological fabrics.Through the stochastic sampling of tissue archetypes delineated by explicit optical characteristics,Monte Carlo simulations possess the theoretical capacity to render unparalleled accuracy in the depiction of exceedingly intricate phenomena.Nonetheless,the quintessential challenge associated with Monte Carlo simulation methodologies resides in their extended computational duration,which significantly impedes the refinement of their precision.Consequently,this discourse is specifically dedicated to exploring innovations in strategies and technologies aimed at expediting Monte Carlo simulations.It delves into the foundational concepts of various acceleration tactics,evaluates these strategies concerning their speed,accuracy,and practicality,and amalgamates a comprehensive overview and critique of acceleration methodologies for Monte Carlo simulations.Ultimately,the discourse envisages prospective trajectories for the employment of Monte Carlo techniques within the domain of tissue optics. 展开更多
关键词 Medical optics photon transport simulation Monte Carlo simulation ACCELERATION
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Simulation of Diode-Pumped Q-Switched Nd:YAG Laser Generating Eye-Safe Signal in IOPO Environment
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作者 Mian M. Ashraf Muhammad Siddique 《Optics and Photonics Journal》 2012年第3期167-172,共6页
Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations,... Numerical simulation of diode-pumped Q-switched Nd:YAG laser leading to the generation of eye-safe signal in singly resonant Intracavity Optical Parametric Oscillator (IOPO) is presented. Starting from rate equations, the time dependent laser equations have been solved numerically, whereas the space-dependent OPO equations analytically. Our results show that 1.4 J diode laser (810 nm) pulse with 200 msec width, delivers 30 mJ Nd:YAG laser (1064 nm) pulse with 5 n-second width. This Nd:YAG laser further generates 9 mJ eye safe signal (1570 nm) pulse with 2.5 n-second width. 展开更多
关键词 simulation Diode LASER Q-SWITCHED Nd:YAG LASER Eye-Safe LASER SIGNAL Idler IOPO Rate Equations Out-Put Power KTP Non-Linear Crystal Pump Beam WAIST
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Relative Impacts of Sea Ice Loss and Atmospheric Internal Variability on the Winter Arctic to East Asian Surface Air Temperature Based on Large-Ensemble Simulations with NorESM2 被引量:1
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作者 Shengping HE Helge DRANGE +4 位作者 Tore FUREVIK Huijun WANG Ke FAN Lise Seland GRAFF Yvan J.ORSOLINI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第8期1511-1526,共16页
To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simu... To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling. 展开更多
关键词 Arctic sea ice loss warm Arcticcold East Asia atmospheric internal variability large-ensemble simulation NorESM2 PAMIP
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Exploring the moderating role of financial development in environmental Kuznets curve for South Africa:fresh evidence from the novel dynamic ARDL simulations approach 被引量:2
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作者 Maxwell Chukwudi Udeagha Marthinus Christoffel Breitenbach 《Financial Innovation》 2023年第1期79-130,共52页
The extant literature has produced mixed evidence on the relationship between finan-cial development and ecological sustainability.This work addresses this conundrum by investigating financial development’s direct an... The extant literature has produced mixed evidence on the relationship between finan-cial development and ecological sustainability.This work addresses this conundrum by investigating financial development’s direct and indirect consequences on ecologi-cal quality utilizing the environmental Kuznets curve(EKC)methodological approach.Our empirical analysis is based on the novel dynamic autoregressive distributed lag simulations approach for South Africa between 1960 and 2020.The results,which used five distinct financial development measures,demonstrate that financial develop-ment boosts ecological integrity and environmental sustainability over the long and short terms.In the instance of South Africa,we additionally confirm the validity of the EKC theory.More importantly,the outcomes of the indirect channels demonstrate that financial development increases energy usage’s role in causing pollution while attenuating the detrimental impacts of economic growth,trade openness,and foreign direct investment on ecological quality.Moreover,the presence of an inadequate financial system is a requirement for the basis of the pollution haven hypothesis(PHH),which we examine using trade openness and foreign direct investment variables.PHH for both of these variables disappears when financial development crosses specified thresholds.Finally,industrial value addition destroys ecological quality while tech-nological innovation enhances it.This research provides some crucial policy recom-mendations and fresh perspectives for South Africa as it develops national initiatives to support ecological sustainability and reach its net zero emissions goal. 展开更多
关键词 Financial development Trade openness CO_(2)emissions Dynamic ARDL simulations Energy consumption EKC COINTEGRATION Economic growth Foreign direct investment Industrial value-added South Africa
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Process simulation and energy integration in the mineral carbonation of blast furnace slag 被引量:3
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作者 Jianqiu Gao Chun Li +8 位作者 Weizao Liu Jinpeng Hu Lin Wang Qiang Liu Bin Liang Hairong Yue Guoquan Zhang Dongmei Luo Siyang Tang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第1期157-167,共11页
Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of s... Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat utilization.In this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process energy.The effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied systematically.The simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue gases.Approximately 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF slag.In addition, the by-product,aluminum ammonium sulfate, is a high value-added product.Preliminary economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed. 展开更多
关键词 Blast FURNACE slag Mineral CARBONATION Process simulation and energy integration Utilization of solid RESIDUALS AMMONIUM ALUM AMMONIUM SULFATE
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