期刊文献+
共找到25,773篇文章
< 1 2 250 >
每页显示 20 50 100
Analysis of factors influencing carbon emissions in the Yangtze River Delta region and projections of carbon peak scenarios 被引量:1
1
作者 SHI Xiong-tian WU Feng-qing +1 位作者 CHEN Yang DAI Li-li 《Ecological Economy》 2024年第1期2-24,共23页
Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon... Based on the supply-side perspective,the improved STIRPAT model is applied to reveal the mechanisms of supply-side factors such as human,capital,technology,industrial synergy,institutions and economic growth on carbon emissions in the Yangtze River Delta(YRD)through path analysis,and to forecast carbon emissions in the YRD from the baseline scenario,factor regulation scenario and integrated scenario to reach the peak.The results show that:(1)Jiangsu's high carbon emission pattern is the main reason for the YRD hindering the synergistic regulation of carbon emissions.(2)Human factors,institutional factors and economic growth factors can all contribute to carbon emissions in the YRD region,while technological and industrial factors can generally suppress carbon emissions in the YRD region.(3)Under the capital regulation scenario,the YRD region has the highest level of carbon emission synergy,with Jiangsu reaching its peak five years earlier.Under the balanced regulation scenario,the YRD region as a whole,Jiangsu,Zhejiang and Anhui reach the peak as scheduled. 展开更多
关键词 Yangtze River Delta carbon peaking scenario forecasting STIRPAT model
下载PDF
Combined Optimal Dispatch of Thermal Power Generators and Energy Storage Considering Thermal Power Deep Peak Clipping and Wind Energy Emission Grading Punishment
2
作者 Junhui Li Xuanzhong Luo +2 位作者 Changxing Ge Cuiping Li Changrong Wang 《Energy Engineering》 EI 2024年第4期869-893,共25页
Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing,which affects the stabilization of the PS(power system).This paper suggests integrated optimal dispatching of thermal powe... Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing,which affects the stabilization of the PS(power system).This paper suggests integrated optimal dispatching of thermal power generators and BESS(battery energy storage system)taking wind energy emission grading punishment and deep peak clipping into consideration.Firstly,in order to minimize wind abandonment,a hierarchical wind abandonment penalty strategy based on fuzzy control is designed and introduced,and the optimal grid-connected power of wind energy is determined as a result of minimizing the peak cutting cost of the system.Secondly,considering BESS and thermal power,the management approach of BESS-assisted virtual peak clipping of thermal power generators is aimed at reducing the degree of deep peak clipping of thermal power generators and optimizing the output of thermal power generators and the charging and discharging power of BESS.Finally,Give an example of how this strategy has been effective in reducing abandonment rates by 0.66% and 7.46% individually for different wind penetration programs,and the daily average can reduce the peak clipping power output of thermal power generators by 42.97 and 72.31 MWh and enhances the effect and economy of system peak clipping. 展开更多
关键词 BESS wind energy deep peak clipping virtual peak clipping wind energy emission grading punishment
下载PDF
Physics-informed machine learning model for prediction of ground reflected wave peak overpressure
3
作者 Haoyu Zhang Yuxin Xu +1 位作者 Lihan Xiao Canjie Zhen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期119-133,共15页
The accurate prediction of peak overpressure of explosion shockwaves is significant in fields such as explosion hazard assessment and structural protection, where explosion shockwaves serve as typical destructive elem... The accurate prediction of peak overpressure of explosion shockwaves is significant in fields such as explosion hazard assessment and structural protection, where explosion shockwaves serve as typical destructive elements. Aiming at the problem of insufficient accuracy of the existing physical models for predicting the peak overpressure of ground reflected waves, two physics-informed machine learning models are constructed. The results demonstrate that the machine learning models, which incorporate physical information by predicting the deviation between the physical model and actual values and adding a physical loss term in the loss function, can accurately predict both the training and out-oftraining dataset. Compared to existing physical models, the average relative error in the predicted training domain is reduced from 17.459%-48.588% to 2%, and the proportion of average relative error less than 20% increased from 0% to 59.4% to more than 99%. In addition, the relative average error outside the prediction training set range is reduced from 14.496%-29.389% to 5%, and the proportion of relative average error less than 20% increased from 0% to 71.39% to more than 99%. The inclusion of a physical loss term enforcing monotonicity in the loss function effectively improves the extrapolation performance of machine learning. The findings of this study provide valuable reference for explosion hazard assessment and anti-explosion structural design in various fields. 展开更多
关键词 Blast shock wave peak overpressure Machine learning Physics-informed machine learning
下载PDF
教育数字化背景下高职多模态PEAK教学模式设计与实施——以智能网联汽车技术课程为例
4
作者 庄紫玮 《哈尔滨职业技术学院学报》 2024年第6期48-51,共4页
随着国家政策和社会需求的推动,教育数字化转型迫在眉睫。课堂是教育教学的主战场,教学是教育实践的根本途径。对教育数字化背景下多模态教学模式进行可行性分析后,构建适合高职教育的多模态PEAK教学模式,设计“三动三式”教学策略,实... 随着国家政策和社会需求的推动,教育数字化转型迫在眉睫。课堂是教育教学的主战场,教学是教育实践的根本途径。对教育数字化背景下多模态教学模式进行可行性分析后,构建适合高职教育的多模态PEAK教学模式,设计“三动三式”教学策略,实施“行动导向六贯穿”,创新“三维五星”联动评价体系,提供岗课融合、数字赋能的实施路径,促进数字技术与高职教育教学深度融合。 展开更多
关键词 教育数字化 多模态 peak教学模式 智能网联汽车技术
下载PDF
Estimation of peak wave period from surface texture motion in videos
5
作者 Haipeng Yu Xiaoliang Chu Guang Yuan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第9期136-144,共9页
Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave... Wave information retrieval from videos captured by a single camera has been increasingly applied in marine observation.However,when the camera observes ocean waves at low grazing angles,the accurate extraction of wave information from videos will be affected by the interference of the fine ripples on the sea surface.To solve this problem,this study develops a method for estimating peak wave periods from videos captured at low grazing angles.The method extracts the motion of the sea surface texture from the video and obtains the peak wave period via the spectral analysis.The calculation results captured from real-world videos are compared with those obtained from X-band radar inversion and tracking buoy movement,with maximum deviations of 8%and 14%,respectively.The analysis of the results shows that the peak wave period of the method has good stability.In addition,this paper uses a pinhole camera model to convert the displacement of the texture from pixel height to actual height and performs moving average filtering on the displacement of the texture,thus conducting a preliminary exploration of the inversion of significant wave height.This study helps to extend the application of sea surface videos. 展开更多
关键词 low grazing angle sea surface texture VIDEO peak wave period significant wave height image matching
下载PDF
Peak Shaving Strategy of Concentrating Solar Power Generation Based on Multi-Time-Scale and Considering Demand Response
6
作者 Lei Fang Haiying Dong +1 位作者 Xiaofei Zhen Shuaibing Li 《Energy Engineering》 EI 2024年第3期661-679,共19页
According to the multi-time-scale characteristics of power generation and demand-side response(DR)resources,as well as the improvement of prediction accuracy along with the approaching operating point,a rolling peak s... According to the multi-time-scale characteristics of power generation and demand-side response(DR)resources,as well as the improvement of prediction accuracy along with the approaching operating point,a rolling peak shaving optimization model consisting of three different time scales has been proposed.The proposed peak shaving optimization model considers not only the generation resources of two different response speeds but also the two different DR resources and determines each unit combination,generation power,and demand response strategy on different time scales so as to participate in the peaking of the power system by taking full advantage of the fast response characteristics of the concentrating solar power(CSP).At the same time,in order to improve the accuracy of the scheduling results,the combination of the day-ahead peak shaving phase with scenario-based stochastic programming can further reduce the influence of wind power prediction errors on scheduling results.The testing results have shown that by optimizing the allocation of scheduling resources in each phase,it can effectively reduce the number of starts and stops of thermal power units and improve the economic efficiency of system operation.The spinning reserve capacity is reduced,and the effectiveness of the peak shaving strategy is verified. 展开更多
关键词 peak shaving strategy concentrating solar power multi-time-scale demand-side response rolling optimization
下载PDF
Assessment of Axial Power Peaking Factors in GHARR-1 LEU Core: A Decadal Simulation Analysis
7
作者 Emmanuel Kwame Ahiave Emmanuel Ampomah-Amoako +1 位作者 Rex Gyeabour Abrefah Mathew Asamoah 《World Journal of Nuclear Science and Technology》 CAS 2024年第1期72-85,共14页
This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the... This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy. 展开更多
关键词 GHARR-1 Power peaking Factor Nuclear Reactor Safety Low Enriched Uranium Core Operational Longevity Thermal Hydraulics
下载PDF
Analysis of Smooth Cepstral Peak Prominence in Hypokinetic Dysarthria Associated With Parkinson’s Disease
8
作者 Qiang LI Abigail WALLACE +4 位作者 Wesley DAVIS Beau ROTH Laura LANGHOFER Shalini NARAYANA Michael CANNITO 《Chinese Journal of Applied Linguistics》 2024年第4期657-669,688,共14页
Smoothed cepstral peak prominence(CPPs)is a measurement of the distance from the prominent cepstral peak to the linear regression line directly beneath it.Variations of CPPs data acquisition and analysis lead to the c... Smoothed cepstral peak prominence(CPPs)is a measurement of the distance from the prominent cepstral peak to the linear regression line directly beneath it.Variations of CPPs data acquisition and analysis lead to the complexity of the clinical cut-off values,and there are no agreeable values for a specific voice disorder,such as hypokinetic dysarthria associated with Parkinson’s disease(PD).This study examined the CPPs in people with hypokinetic dysarthria associated with PD compared with healthy participants.Results demonstrated significant differences in speech tasks of sustained vowel and connected speech,with CPPs of connected speech more sensitive to dysphonia and gender difference in PD participants.Males in PD participants presented higher CPPs for sustained vowels and lower CPPs for connected speech than females.It is implied that a consistent clinical application protocol is necessary,and multiple acoustic measures are needed to ensure the accuracy of clinical decisions. 展开更多
关键词 cepstral peak prominence hypokinetic dysarthria VOICE Parkinson’s disease motor speech disorders
下载PDF
Peak Particle Velocity Predicting Equation Associated with the Propagation of Vibrations Induced by Blasting in a Mine and Impacts on the Physical Degradation of Houses: The Case of the Yaramoko Mine, Bagassi, Burkina Faso
9
作者 Richard Zoundi Antoine Béré +1 位作者 Joel Martial Balkoulga Philibert Sawadogo 《Journal of Minerals and Materials Characterization and Engineering》 2024年第6期316-333,共18页
This study utilizes empirical equations to describe the propagation of vibrations induced by blasting, with the goal of predicting the attenuation of Peak Particle Velocity (PPV) at the Yaramoko mine in Bagassi, Burki... This study utilizes empirical equations to describe the propagation of vibrations induced by blasting, with the goal of predicting the attenuation of Peak Particle Velocity (PPV) at the Yaramoko mine in Bagassi, Burkina Faso, a site characterized by granitoid rock. Four empirical PPV prediction equations were employed, so-called Duvall & Fogelson (or the United States Bureau of Mines “USBM”), Langefors and Kihlstrom, Ambressys-Hendron, and the Bureau of Indian Standard. The constant parameters for each of these equations, referred to as site constants, were derived from linear regression curves. The results show that the site constants k, a, and b of 4762, 0.869, and 1.737, respectively, derived from the general prediction equation by Davies, PPV = kQaD−b, based on Duvall & Fogelson, are in good agreement with values of 4690, 0.9, and 1.69, respectively, for similar rock types in Spain. Regarding the impacts of blasting on houses, the findings indicate that houses built from laterite-block bricks in the village of Bagassi are the most vulnerable to vibration waves, followed by those constructed with cinder-block bricks. In contrast, houses made of banco bricks are the most resilient. Additionally, it was determined that during blasting operations, adjusting the blasting parameters to ensure the PPV does not exceed 2 mm/s at the level of nearby dwellings can minimize the appearance of cracks in houses. 展开更多
关键词 peak Particle Velocity BLASTING Propagation of Blasting Vibrations Cracks on Houses PPV Equation
下载PDF
Spatiotemporal variations of ecosystem services and driving factors in the Tianchi Bogda Peak Natural Reserve of Xinjiang,China
10
作者 ZHU Haiqiang WANG Jinlong +2 位作者 TANG Junhu DING Zhaolong GONG Lu 《Journal of Arid Land》 SCIE CSCD 2024年第6期816-833,共18页
Nature reserves play a significant role in providing ecosystem services and are key sites for biodiversity conservation.The Tianchi Bogda Peak Natural Reserve(TBPNR),located in Xinjiang Uygur Autonomous Region,China,i... Nature reserves play a significant role in providing ecosystem services and are key sites for biodiversity conservation.The Tianchi Bogda Peak Natural Reserve(TBPNR),located in Xinjiang Uygur Autonomous Region,China,is an important ecological barrier area in the temperate arid zone.The evaluation of its important ecosystem services is of great significance to improve the management level and ecological protection efficiency of the reserve.In the present study,we assessed the spatiotemporal variations of four ecosystem services(including net primary productivity(NPP),water yield,soil conservation,and habitat quality)in the TBPNR from 2000 to 2020 based on the environmental and social data using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.In addition,the coldspot and hotspot areas of ecosystem services were identified by hotspot analysis,and the trade-off and synergistic relationships between ecosystem services were analyzed using factor analysis in a geographic detector.During the study period,NPP and soil conservation values in the reserve increased by 48.20%and 25.56%,respectively;conversely,water yield decreased by 16.56%,and there was no significant change in habitat quality.Spatially,both NPP and habitat quality values were higher in the northern part and lower in the southern part,whereas water yield showed an opposite trend.Correlation analysis revealed that NPP showed a synergistic relationship with habitat quality and soil conservation,and exhibited a trade-off relationship with water yield.Water yield and habitat quality also had a trade-off relationship.NPP and habitat quality were affected by annual average temperature and Normalized Difference Vegetation Index(NDVI),respectively,while water yield and soil conservation were more affected by digital elevation model(DEM).Therefore,attention should be paid to the spatial distribution and dynamics of trade-off and synergistic relationships between ecosystem services in future ecological management.The findings of the present study provide a reference that could facilitate the sustainable utilization of ecosystem services in the typical fragile areas of Northwest China. 展开更多
关键词 net primary productivity(NPP) water yield soil conservation habitat quality Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model geographic detector Tianchi Bogda peak Natural Reserve
下载PDF
基于峰值检测的便携式钢筘测量仪研发
11
作者 徐帅 杨晓芳 +2 位作者 毛雷 孙百胜 宋子俊 《毛纺科技》 北大核心 2025年第1期97-103,共7页
针对纺织生产现场随时进行机上快速测量的使用需求,研发了一款采用振动传感器和位移传感器的便携式钢筘筘号测量仪。首先,在分析振动信号的基础上,通过统计振动信号波峰数量获得筘齿数。其次,在统计波峰过程中,引入并优化无参数的自动... 针对纺织生产现场随时进行机上快速测量的使用需求,研发了一款采用振动传感器和位移传感器的便携式钢筘筘号测量仪。首先,在分析振动信号的基础上,通过统计振动信号波峰数量获得筘齿数。其次,在统计波峰过程中,引入并优化无参数的自动多尺度峰值检测算法,降低其时空复杂度,实现筘齿的准确计数。最后,设计便携式钢筘测量仪硬件、软件架构,硬件上采用高性能STM32微控制器,能较好采集数据和运行算法;软件上增添时间和位移的双重条件检查,增加测量可靠性。实验结果表明:基于优化峰值检测算法的便携式钢筘测量仪,能够较好地测量工厂常用钢筘的筘号,并具有操作方便、无需设置阈值等优点。 展开更多
关键词 钢筘筘号 峰值检测 算法优化 钢筘检测 信号处理 纺织仪器
下载PDF
中国碳市场的价格有效性评估与优化设计研究
12
作者 刘自敏 李莉 李兴 《统计与信息论坛》 北大核心 2025年第1期77-91,共15页
实现碳排放权交易价格有效性预测与设计是稳定全国碳排放权交易市场的基础。在利用机器学习预测碳排放权交易价格的基础上,对碳市场的碳价进行了评估与设计。以湖北碳交易市场碳价格为例,基于2014-2022年的碳交易价格日度数据,构建混合... 实现碳排放权交易价格有效性预测与设计是稳定全国碳排放权交易市场的基础。在利用机器学习预测碳排放权交易价格的基础上,对碳市场的碳价进行了评估与设计。以湖北碳交易市场碳价格为例,基于2014-2022年的碳交易价格日度数据,构建混合遗传粒子群神经网络(GAPSO-BP)定价模型,对碳达峰目标下的区域碳市场及全国统一碳市场的碳价进行有效性评估与优化设计。研究发现:GAPSO-BP模型预测的碳交易价格误差小,通过使用更高精度的GAPSO-BP模型对变量进行降维筛选,发现经济发展水平和太阳能、天然气、煤炭能源价格对碳价格影响最大。场景分析显示,发展绿色清洁能源在经济高速增长的情况下碳交易价格效果最好,在经济中等发展的情况下会受到抑制,在经济低速发展的情况下效果不显著。基于碳达峰目标,通过比较试点碳市场的现有平均价格和模拟预测的平均价格,评估出天津碳试点的碳价最为有效,而上海碳试点的碳价有效性最差。为顺利在2030年前实现“碳达峰”目标,全国统一碳市场最优碳价应设定为50.27元/吨较为合适。基于研究结论,从宏观调控决策因素、发展绿色清洁能源、考虑区域碳减排成本差异和建立相应的配额缓冲机制提出具体建议,为顺利实现试点碳市场与全国碳市场有效衔接及碳达峰提供了有益的理论支撑与路径选择。 展开更多
关键词 碳达峰 碳市场 GAPSO-BP模型 价格有效性 碳价设计
下载PDF
多情景视角下丝绸之路经济带沿线省份碳达峰预测
13
作者 张朝辉 张靖雅 于师琪 《生态经济》 北大核心 2025年第1期80-88,共9页
基于碳达峰碳中和目标的战略背景,结合“共建绿色丝绸之路”的时代倡议,考虑丝绸之路经济带国内沿线省份的产业发展态势,运用STIRPAT拓展模型,构建碳排放量与各影响因素的预测模型,进一步设置不同情景模式,预测丝绸之路经济带沿线省份2... 基于碳达峰碳中和目标的战略背景,结合“共建绿色丝绸之路”的时代倡议,考虑丝绸之路经济带国内沿线省份的产业发展态势,运用STIRPAT拓展模型,构建碳排放量与各影响因素的预测模型,进一步设置不同情景模式,预测丝绸之路经济带沿线省份2021—2040年的碳达峰趋势。结果表明:(1)能源消耗水平对碳排放的影响最大,是影响丝绸之路经济带沿线省份碳达峰的最重要因素。(2)技术突破模式下,丝绸之路经济带沿线省份在2030年实现碳达峰,峰值4808.43×106吨;政策调控和数字经济模式下,丝绸之路经济带沿线省份在2035年实现碳达峰,峰值分别为5519.46×106吨和4988.32×106吨;基准模式下,丝绸之路经济带沿线省份未能实现碳达峰。(3)内蒙古、陕西和新疆是碳达峰重点关注区,应加快政策落地、加大技术突破、加强数字经济,确保如期实现碳达峰。 展开更多
关键词 绿色丝绸之路经济带 技术突破 数字经济 碳达峰 情景预测
下载PDF
峰前循环扰动下的深埋花岗岩特征参数演化规律与损伤变量研究
14
作者 张胜 徐鼎平 +2 位作者 石汉明 吴小刚 易明尚 《岩土力学》 北大核心 2025年第1期73-87,共15页
深部地下厂房开挖过程中所产生的循环扰动会导致围岩损伤,从而降低围岩力学性质。为揭示叶巴滩水电站地下厂房中深埋花岗岩在循环扰动后的分级卸载破坏特性和损伤过程,首先进行了围压为30 MPa、循环应力分别为12.5%~17.5%(低应力)、10.0... 深部地下厂房开挖过程中所产生的循环扰动会导致围岩损伤,从而降低围岩力学性质。为揭示叶巴滩水电站地下厂房中深埋花岗岩在循环扰动后的分级卸载破坏特性和损伤过程,首先进行了围压为30 MPa、循环应力分别为12.5%~17.5%(低应力)、10.0%~37.5%(中应力)、62.5%~72.5%(高应力)峰值强度的峰前恒幅循环扰动,在此基础上进行了3种分级卸围压试验,进而开展了峰前循环扰动下的深埋花岗岩特征参数演化规律分析与损伤变量构建。研究结果显示:低、中应力循环扰动对花岗岩造成的损伤可忽略不计,但高应力恒幅循环扰动会导致轻微损伤。在不同分级卸围压路径下,岩样变形主要集中在最后3个阶段的围压降低过程中,其宏观破裂模式为压剪破坏;弹性模量呈下降趋势,泊松比呈上升趋势,最大剪胀角基本相同;高轴压恒幅循环扰动后的分级卸围压试验下的岩样累积应变能最高,表现出更强的脆性破坏倾向。此外,分级卸围压下的岩样应变能均高于常规三轴压缩下的岩样应变能,后者可作为分级卸围压岩样是否进入加速损伤破裂阶段的判别阈值。采用侧向应变响应法和裂纹体积应变法确定的深埋花岗岩闭合应力、起裂应力和损伤应力分别为其峰值强度的17.9%、42.7%和73.8%,并据此建立了基于裂纹体积应变的损伤变量,进而划分了深部硬岩损伤过程的4个阶段。研究成果可为分析高应力花岗岩的破坏过程提供试验和理论支撑。 展开更多
关键词 峰前循环扰动 分级卸载 特征阈值 侧向应变响应法 裂纹体积应变
下载PDF
长直坑道内爆炸冲击波相似规律研究
15
作者 王新颖 秦毅 +1 位作者 赵涯 綦鸿力 《沈阳理工大学学报》 CAS 2025年第1期65-71,共7页
通过长直坑道内炸药爆炸后冲击波的超压峰值变化研究坑道内爆炸冲击波的相似规律。使用AUTODYN软件建立长直坑道仿真模型,采用映射方法将3.25 kg当量的球形TNT炸药在空气中的爆炸状态映射到长直坑道中,采用经典试验结果对模型进行验证... 通过长直坑道内炸药爆炸后冲击波的超压峰值变化研究坑道内爆炸冲击波的相似规律。使用AUTODYN软件建立长直坑道仿真模型,采用映射方法将3.25 kg当量的球形TNT炸药在空气中的爆炸状态映射到长直坑道中,采用经典试验结果对模型进行验证。根据几何相似原理,通过改变坑道尺寸、坑道截面形状、炸点位置和炸药当量建立多组不同的模型,模拟计算得到坑道内爆炸冲击波的超压峰值,分析超压峰值的相似规律。结果表明,保持坑道截面积不变、改变截面形状及保持爆心距与炸药当量的比值不变、改变炸药当量,各模型计算得到的冲击波超压峰值具有相似规律。采用本文方法可对其他满足几何相似原理的坑道内爆炸冲击波参数进行预测,为地下空间设施的安全设计提供参考。 展开更多
关键词 长直坑道 冲击波 超压峰值 相似规律
下载PDF
Chopping-peaking开关形成高功率超宽带双极脉冲的实验研究 被引量:12
16
作者 樊亚军 石磊 +4 位作者 刘国治 汪文秉 周金山 刘峰 朱郁丰 《强激光与粒子束》 EI CAS CSCD 北大核心 2004年第4期501-504,共4页
 设计研制了一种chopping peaking组合开关型高功率双极脉冲形成装置,通过调节两个开关的导通时刻来得到不同形状的双极脉冲。理想情况下,形成的双极脉冲电压峰 峰值等于入射脉冲峰值电压的2倍,实验中入射脉冲峰值电压为205kV的单极脉...  设计研制了一种chopping peaking组合开关型高功率双极脉冲形成装置,通过调节两个开关的导通时刻来得到不同形状的双极脉冲。理想情况下,形成的双极脉冲电压峰 峰值等于入射脉冲峰值电压的2倍,实验中入射脉冲峰值电压为205kV的单极脉冲,获得了最大峰 峰电压为360kV的双极脉冲,是入射脉冲峰值电压的1.76倍。双极脉冲的持续时间可以改变,最大值为单极脉冲的脉宽。入射脉冲上升时间越小,得到的双极脉冲峰 峰电压就越大。 展开更多
关键词 超宽带 双极脉冲 陡化 chopping开关 peaking开关
下载PDF
考虑快速变负荷和灵活性供需匹配的耦合系统优化调度
17
作者 周念成 戴旭晖 +2 位作者 池源 徐飞 常东锋 《电力系统自动化》 北大核心 2025年第1期117-127,共11页
可再生能源与快速变负荷改造的火电机组在同一并网点对外形成耦合系统,是提升沙漠、戈壁、荒漠等灵活性发电资源缺乏而可再生能源比例较高地区灵活性的有效手段。为了挖掘火电机组改造后的耦合系统经济性与灵活性,文中提出一种风光火耦... 可再生能源与快速变负荷改造的火电机组在同一并网点对外形成耦合系统,是提升沙漠、戈壁、荒漠等灵活性发电资源缺乏而可再生能源比例较高地区灵活性的有效手段。为了挖掘火电机组改造后的耦合系统经济性与灵活性,文中提出一种风光火耦合系统多目标优化调度方法。首先,根据实际测算的火电机组灵活性改造后的运行煤耗数据,拟合了机组爬坡过程的煤耗计算公式,并分析了火电快速变负荷能力提高对耦合系统经济性和灵活性的影响。在此基础上,将日综合运行收益与灵活性供需匹配度作为目标函数,考虑包括阶梯式爬坡率在内的系统运行约束,构建多目标优化调度模型。通过在优化算法中使用分组关联多项式变异算子,提高了算法对维度较高、约束较复杂的电力系统多目标优化调度问题的求解能力。最后,以某地区耦合系统为例进行了优化调度仿真。结果表明,文中所述方法能够获得综合经济性与灵活性相对更优的耦合系统优化调度方案。 展开更多
关键词 耦合系统 调峰 快速变负荷 阶梯式爬坡率 灵活性供需匹配 多目标优化调度
下载PDF
O_2 peak:释义与应用 被引量:9
18
作者 张建国 施启蓉 张雪琴 《体育科学》 CSSCI 北大核心 2007年第7期80-85,共6页
O2 peak常用于评价不同人群有氧工作能力,是近年来国外运动医学文献中出现频度较高的一个专业术语。就O2 peak这一术语的解释、与O2 max的区别、应用范围以及再测信度进行了综述。尽管学者们对.O2 peak有着不同的解释,但是,O2... O2 peak常用于评价不同人群有氧工作能力,是近年来国外运动医学文献中出现频度较高的一个专业术语。就O2 peak这一术语的解释、与O2 max的区别、应用范围以及再测信度进行了综述。尽管学者们对.O2 peak有着不同的解释,但是,O2 peak在研究对象、判断标准、运动负荷方法等方面与.O2 max存在明显的差异。O2 peak常用于不同人群的流行病学研究,具有较高的实用性。许多研究表明,O2 peak有很高的再测信度,是一项稳定性较好的测试指标。 展开更多
关键词 VO2 peak VO2MAX 术语解释 应用范围
下载PDF
基于疏散引导的高峰时段地铁站应急疏散方案优化
19
作者 田杰 苏宇鹏 +1 位作者 吴桐 朱震军 《重庆交通大学学报(自然科学版)》 北大核心 2025年第1期96-103,126,共9页
为保障突发事故时高峰时段地铁站行人应急疏散的效率与安全,对现有疏散方案进行了优化。首先,分析了高峰时段地铁站的行人疏散特征,阐明了在高峰时段增设疏散引导的必要性,总结了疏散中常见的瓶颈拥堵点。随后,针对各瓶颈拥堵点的位置... 为保障突发事故时高峰时段地铁站行人应急疏散的效率与安全,对现有疏散方案进行了优化。首先,分析了高峰时段地铁站的行人疏散特征,阐明了在高峰时段增设疏散引导的必要性,总结了疏散中常见的瓶颈拥堵点。随后,针对各瓶颈拥堵点的位置设计了疏散引导措施,分别设计了现有疏散方案与增设疏散引导后的优化方案。最后,通过Anylogic软件对2组疏散方案进行了仿真,对比分析了多个疏散评价指标,验证了优化方案的有效性。研究结果表明,现有疏散方案可在平峰时段按时完成疏散,但其在高峰时段的总疏散时间超过了地铁安全疏散规范中要求的360 s,而优化方案在高峰时段的总疏散时间为352 s,闸机最长通过时间为278 s,均优于现有疏散方案。研究结果可为高峰时段地铁站疏散方案中疏散引导的具体设计提供参考。 展开更多
关键词 交通运输工程 疏散引导 高峰时段 地铁车站 疏散方案优化 多指标评价
下载PDF
我国茶产业低碳化发展研究与实践进展
20
作者 胡强 唐晏 +4 位作者 朱迪 张优 王志博 陈超 陈富桥 《中国茶叶》 2025年第1期21-28,共8页
“双碳”目标下,我国农业的绿色发展模式转型是实现碳达峰和碳中和目标的必然选择。茶业是农业固碳减排的重要领域之一,探索茶产业低碳化发展是践行国家“双碳”战略的重要抓手。文章从茶叶低碳研究进展、茶叶低碳生产的探索与研究、生... “双碳”目标下,我国农业的绿色发展模式转型是实现碳达峰和碳中和目标的必然选择。茶业是农业固碳减排的重要领域之一,探索茶产业低碳化发展是践行国家“双碳”战略的重要抓手。文章从茶叶低碳研究进展、茶叶低碳生产的探索与研究、生态低碳茶的认证与推广、茶园碳汇研究等方面,总结了我国利用茶园生态系统发挥其碳汇功能和推动茶产业绿色低碳发展的“双碳”研究与实践经验,分析了我国茶产业践行“双碳”战略中存在的不足,进而提出了推进我国茶产业低碳化发展的对策与建议,以期为我国茶产业高质量发展提供支撑与依据。 展开更多
关键词 “双碳”战略 茶产业 生态低碳茶 生态低碳认证 对策建议
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部