期刊文献+
共找到859篇文章
< 1 2 43 >
每页显示 20 50 100
Hybrid Deep Learning Architecture to Forecast Maximum Load Duration Using Time-of-Use Pricing Plans
1
作者 Jinseok Kim Babar Shah Ki-Il Kim 《Computers, Materials & Continua》 SCIE EI 2021年第7期283-301,共19页
Load forecasting has received crucial research attention to reduce peak load and contribute to the stability of power grid using machine learning or deep learning models.Especially,we need the adequate model to foreca... Load forecasting has received crucial research attention to reduce peak load and contribute to the stability of power grid using machine learning or deep learning models.Especially,we need the adequate model to forecast the maximum load duration based on time-of-use,which is the electricity usage fare policy in order to achieve the goals such as peak load reduction in a power grid.However,the existing single machine learning or deep learning forecasting cannot easily avoid overfitting.Moreover,a majority of the ensemble or hybrid models do not achieve optimal results for forecasting the maximum load duration based on time-of-use.To overcome these limitations,we propose a hybrid deep learning architecture to forecast maximum load duration based on time-of-use.Experimental results indicate that this architecture could achieve the highest average of recall and accuracy(83.43%)compared to benchmark models.To verify the effectiveness of the architecture,another experimental result shows that energy storage system(ESS)scheme in accordance with the forecast results of the proposed model(LSTM-MATO)in the architecture could provide peak load cost savings of 17,535,700 KRW each year comparing with original peak load costs without the method.Therefore,the proposed architecture could be utilized for practical applications such as peak load reduction in the grid. 展开更多
关键词 load forecasting deep learning hybrid architecture maximum load duration time-of-use
在线阅读 下载PDF
Annual Maximum Loads Estimation Modeling for Kingdom of Bahrain
2
作者 Isa S. Qamber 《Engineering(科研)》 2013年第1期104-107,共4页
The present paper proposes the impact of the air temperature on electricity demand as expected. The annual maximum load is recorded versus the years starting by the year 2009. At present, the graph fitting was applied... The present paper proposes the impact of the air temperature on electricity demand as expected. The annual maximum load is recorded versus the years starting by the year 2009. At present, the graph fitting was applied with some mathematical and computational tools considering the lower values, the higher values and the average values of the annual maximum loads of Kingdom of Bahrain. For the three scenarios, the models are obtained by curve fitting technique. As well, the model of actual loads is obtained finally which has mostly the closest values obtained. 展开更多
关键词 ANNUAL maximum load CURVE FITTING load Scenarios
在线阅读 下载PDF
Assessment of the maximum allowed acid deposition load at current stage in China 被引量:1
3
作者 Bingwen Li Zhangwei Wang Xiaoshan Zhang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2017年第6期140-144,共5页
Soil acidification caused by acid deposition has been significant in some forests in southern China. We present an approach for assessing the current stage maximum allowed load (SML) of acid deposition for terrestri... Soil acidification caused by acid deposition has been significant in some forests in southern China. We present an approach for assessing the current stage maximum allowed load (SML) of acid deposition for terrestrial system in the country. The main idea was that soil base cation exchange as a finite buffer to acidity was included in the soil acidity mass balance calculation at current acidification stage. We calculated the SML for five forests in southern China. The usual critical loads for the same forests were also calculated by the steady state mass balance model for comparison. The results showed that the SML is a more tolerant limit than the critical load for the forests with soils not acidified seriously at current stage. However, the SML become a more stringent limit to acid deposition when the forest soils have acidified seriously to very low base cation saturation. In this case the SML assessment is beneficial for the soils recovering from a serious acidified state. Based on a national scale database, the SML mapping for non-agricultural soil system in China was carried out. 展开更多
关键词 Acid depositionStage maximum loadCritical load
原文传递
Estimation of the Maximum Annual Loads Modeling for Kingdom of Bahrain 被引量:2
4
作者 Isa Salman Qamber 《Journal of Energy and Power Engineering》 2013年第10期2006-2011,共6页
The present paper proposes the impact of the air temperature on electricity demand as expected. It is clear that the annual maximum load is recorded versus the years starting by the year 2009 up to 2012. At present, t... The present paper proposes the impact of the air temperature on electricity demand as expected. It is clear that the annual maximum load is recorded versus the years starting by the year 2009 up to 2012. At present, the graph fitting technique is applied with some mathematical and computational tools based on the actual values of the years 2009 up to 2012 considering the lower values, the higher values and the average values of the annual maximum loads for Kingdom of Bahrain. For the three scenarios, the models are obtained by curve fitting technique. As well, the model of actual loads is obtained finally which has mostly the closest values obtained. 展开更多
关键词 Annual maximum load curve fitting load scenarios.
在线阅读 下载PDF
Predicting the Maximum Load of Reinforced-Concrete Pipe Columns
5
作者 Paul Nibasumba 刘西拉 《Tsinghua Science and Technology》 SCIE EI CAS 2004年第2期153-159,共7页
To simplify the calculation of the maximum load at which instability occurs for reinforced-concrete pipe columns under eccentric compression, a method based on the transformed cross-sectional area of the column and th... To simplify the calculation of the maximum load at which instability occurs for reinforced-concrete pipe columns under eccentric compression, a method based on the transformed cross-sectional area of the column and the concrete secant modulus of elasticity is proposed, consisting of an iterative process in which a sequence of lateral deflections is at column mid-height. The method assumes the deflected shape of the column as a half cosine wave. Analytical results were compared with experimental values obtained from 16 reinforced-concrete pipe columns. Using deflection at column mid-height recorded during the loading proc-ess, a typical load-deflection curve can be plotted and used to describe column behavior. The experimental results demonstrate that the failure of concrete columns is a process. The starting point is the cracking load point, when cracks are initiated in the concrete of the tensile zone of the critical cross-section of specimens. The maximum load point is the top of the failure process, and then the maximum bending moment occurs. The first point represents instability while the second one corresponds to the strength failure of the columns. The experimental results are close to the analytical values. The method is simple and can be used for stabil-ity analysis of reinforced-concrete pipe columns. 展开更多
关键词 maximum load reinforced-concrete pipe column
原文传递
Prediction of a maximum pull-out load of anchor bolts using an optimal combination model 被引量:2
6
作者 Ma Wenjie Wang Binglong +1 位作者 Wang Xu Wang Bolin 《Journal of Southeast University(English Edition)》 EI CAS 2021年第2期199-208,共10页
The mixed model of improved exponential and power function and unequal interval gray GM(1,1)model have poor accuracy in predicting the maximum pull-out load of anchor bolts.An optimal combination model was derived usi... The mixed model of improved exponential and power function and unequal interval gray GM(1,1)model have poor accuracy in predicting the maximum pull-out load of anchor bolts.An optimal combination model was derived using the optimally weighted combination theory and the minimum sum of logarithmic squared errors as the objective function.Two typical anchor bolt pull-out engineering cases were selected to compare the performance of the proposed model with those of existing ones.Results showed that the optimal combination model was suitable not only for the slow P-s curve but also for the steep P-s curve.Its accuracy and stable reliability,as well as its prediction capability classification,were better than those of the other prediction models.Therefore,the optimal combination model is an effective processing method for predicting the maximum pull-out load of anchor bolts according to measured data. 展开更多
关键词 anchor bolt maximum pull-out load mixed model of improved exponential and power function(MIEPF)model unequal interval gray GM(1 1)model optimal combination model
在线阅读 下载PDF
Variable Parameter Nonlinear Control for Maximum Power Point Tracking Considering Mitigation of Drive-train Load 被引量:2
7
作者 Zaiyu Chen Minghui Yin +3 位作者 Lianjun Zhou Yaping Xia Jiankun Liu Yun Zou 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第2期252-259,共8页
Since mechanical loads exert a significant influence on the life span of wind turbines, the reduction of transient load on drive-train shaft has received more attention when implementing a maximum power point tracking... Since mechanical loads exert a significant influence on the life span of wind turbines, the reduction of transient load on drive-train shaft has received more attention when implementing a maximum power point tracking U+0028 MPPT U+0029 controller. Moreover, a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue. However, for the existing control strategies based on nonlinear model of wind turbines, the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft. Hence, in this paper, a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously. Then, simulations on FAST U+0028 Fatigue, Aerodynamics, Structures, and Turbulence U+0029 code and experiments on the wind turbine simulator U+0028 WTS U+0029 based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load. © 2017 Chinese Association of Automation. 展开更多
关键词 AERODYNAMICS Controllers Economic and social effects maximum power point trackers Wind power Wind turbines
在线阅读 下载PDF
Research on Maximum Power Point Tracking in Redundant Load Mode for Photovoltaic System 被引量:1
8
作者 王建军 陈善本 邵宇丰 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第3期257-262,共6页
In order to ensure that the photovoltaic(PV) array always works at the global maximum point of power to increase the system's overall efficiency, this paper leads the study on maximum power point tracking(MPPT) in... In order to ensure that the photovoltaic(PV) array always works at the global maximum point of power to increase the system's overall efficiency, this paper leads the study on maximum power point tracking(MPPT) in redundant load mode. A new control system is designed by combining the redundant electronic load module, embedded controller, supportive capacitor and boost circuit. The system adjusts duty ratio of boost circuit dynamically based on the maximum power point parameter provided by redundant load unit in order to realize MPPT. An experiment shows that no matter whether system is under an even illumination or partly perturbed by shadow, this method can find the exact maximum power point. 展开更多
关键词 photovoltaic(PV) array partial shadow redundant load maximum power point tracking(MPPT) control system
原文传递
Total Maximum Allocated Loads on Stoichiometry of Nitrogen and Identification of Critical Form in Jiaozhou Bay, China
9
作者 LIN Guohong SONG Xianli +3 位作者 LU Dongliang LI Keqiang LIANG Shengkang WANG Xiulin 《Journal of Ocean University of China》 SCIE CAS CSCD 2020年第3期622-632,共11页
Total pollutant load control management for total dissolved nitrogen(TDN) is an urgent task required to gain a good water quality status in Jiaozhou Bay(JZB), China. In this paper, the stoichiometry of multiform TDN o... Total pollutant load control management for total dissolved nitrogen(TDN) is an urgent task required to gain a good water quality status in Jiaozhou Bay(JZB), China. In this paper, the stoichiometry of multiform TDN on land-ocean interactions associated with marine biogeochemical reaction(LOIMBR) was studied by modeling the load-response relationship based on a three-dimensional water quality model of nitrogen in JZB. The results showed that the stoichiometry on LOIMBR of dissolved organic nitrogen(DON), NO3-N and NH4-N was 3:1:1, with one-third of the contribution on the concentration of dissolved inorganic nitrogen(DIN) in JZB for the land-based DON loads to DIN loads. Based on the stoichiometric relationship of nitrogen forms, the total maximum allocated load(TMAL) of equivalent TDN(ETDN) was approximately 5300 t a^-1 in JZB, equivalent to the TMAL of 5700, 5800 and 15600 t a^-1 for NH4-N, NO3-N and DON, respectively. According to the loads of ETDN, there were four outfalls overloaded in JZB in 2015, which lie in the head of the bay. In the four overloaded outfalls, besides NO3-N, NH4-N was the critical nitrogen control form for Moshui River, while DON for Dagu River and Haibo River. The results of numerical experiments further showed that JZB will achieve good water quality after 7 years by implementation of the 'different emission reduction' based on TMAL of ETDN, which is significantly better than 'equal percent removal'. 展开更多
关键词 total dissolved nitrogen water quality STOICHIOMETRY total maximum allocated load Jiaozhou Bay
在线阅读 下载PDF
基于级进延展冷镦工艺的大长径比薄壁管件成形优化
10
作者 孙进 陈野 +1 位作者 朱兴龙 黄小建 《锻压技术》 北大核心 2026年第2期7-14,共8页
针对常见的大长径比薄壁管件热锻工艺存在的温度难以控制、尺寸精度低的问题,以长径比为5.3的气弹簧用油气缸为例,提出一种先镦粗后级进延展式冷镦成形方法。在搭建三维模型的基础上,利用Deform-3D软件对拟定工艺的金属流动规律、成形... 针对常见的大长径比薄壁管件热锻工艺存在的温度难以控制、尺寸精度低的问题,以长径比为5.3的气弹簧用油气缸为例,提出一种先镦粗后级进延展式冷镦成形方法。在搭建三维模型的基础上,利用Deform-3D软件对拟定工艺的金属流动规律、成形载荷和断裂趋势等进行分析,验证了工艺的可行性。结合仿真结果,以薄壁延伸最大成形载荷为优化目标,利用正交试验与极差分析,得出各因素对最大成形载荷的影响程度依次为:首次缩径值a>入模角λ>冲头下压速度v,并选取了最优工艺参数组合:冲头下压速度v=15 mm·s^(-1)、首次缩径值a=0.70 mm、入模角λ=7°。优化后的工艺参数使最大成形载荷降低了18.15%,提高了薄壁成形质量。研究结果为同类大长径比薄壁管件的研究提供了理论参考。 展开更多
关键词 大长径比薄壁管件 级进延展冷镦工艺 最大成形载荷 金属流动规律 损伤值
原文传递
长距离带式输送机新型起动曲线及其动态特性分析
11
作者 袁媛 寇俊雄 周利东 《机械传动》 北大核心 2026年第1期155-162,191,共9页
【目的】针对长距离带式输送机起动过程中的纵向振动问题,基于输送带黏弹特性分析,构建了带式输送机的动力学方程。以实际工程中的长距离带式输送机为例,利用AMESim平台搭建了动力学仿真模型,旨在探究起动过程中的加速度曲线及最佳加载... 【目的】针对长距离带式输送机起动过程中的纵向振动问题,基于输送带黏弹特性分析,构建了带式输送机的动力学方程。以实际工程中的长距离带式输送机为例,利用AMESim平台搭建了动力学仿真模型,旨在探究起动过程中的加速度曲线及最佳加载时间。【方法】首先,分析了常见起动曲线对输送带动张力的影响,提出一种“正弦+抛物线”的新型组合起动曲线;其次,通过引入爬行段和调整预起动阶段的速度,对该曲线进行了优化;最后,对比分析了不同加载时间下输送带的张力变化规律。【结果】结果表明,在起动过程中采用优化后的“正弦+抛物线”组合起动曲线后,输送带产生的最大张力值较常用的正弦加速度曲线降低了5.8%;在系统稳定运行后加载物料,可有效降低输送带受到的张力冲击,从而延长设备使用寿命。 展开更多
关键词 带式输送机 起动曲线 AMESIM 最大张力值 动态特性 负载
在线阅读 下载PDF
深埋无中导洞连拱隧道过程荷载计算方法研究
12
作者 张建 孙纬宇 +2 位作者 严松宏 王永刚 王文 《岩土工程学报》 北大核心 2026年第1期45-53,共9页
无中导洞连拱隧道规避了传统连拱隧道施工工序繁杂、应力转换频繁等缺点,近年来取得了越来越广泛的应用,而该新型结构的围岩压力计算方法并未有统一的标准可循。基于普氏理论及过程设计方法,考虑先行洞支护结构对后行洞塌落拱高度的抑... 无中导洞连拱隧道规避了传统连拱隧道施工工序繁杂、应力转换频繁等缺点,近年来取得了越来越广泛的应用,而该新型结构的围岩压力计算方法并未有统一的标准可循。基于普氏理论及过程设计方法,考虑先行洞支护结构对后行洞塌落拱高度的抑制作用及后行洞开挖对先行洞围岩压力的加剧影响,建立了深埋无中导洞连拱隧道过程荷载计算方法,最后通过与典型工程现场监控量测结果及参考文献计算方法比对分析。研究结果表明,通过应力分布组合的方式确定先行洞支护结构支撑能力能够量化对后行洞围岩压力的抑制作用;定量分析影响围岩压力的4个主要因素影响程度(围岩级别S(32.66%)、先行洞开挖宽度W_(1)(28.02%)、后行洞开挖宽度W_(2)(22.34%)、先行洞支护强度G(16.99%)),使得后行洞开挖对先行洞围岩压力影响系数的取值更加合理。通过对深埋无中导洞连拱隧道过程荷载计算方法的求解,能够为无中导洞连拱隧道支护结构提供较为科学合理的设计依据。 展开更多
关键词 连拱隧道 普氏理论 过程荷载 最大隶属度原则
原文传递
特殊条件下单桩静载试验加载量取值探讨
13
作者 周元 《工程建设》 2026年第3期27-33,共7页
单桩静载试验是评价单桩承载力的核心方法,合理确定静载试验加载量对保障桩基安全至关重要。文章对相关规范中单桩静载试验加载量取值要求进行阐述,针对常规加载量按照单桩承载力特征值两倍取值的适用性问题,对4种特殊条件下的桩基进行... 单桩静载试验是评价单桩承载力的核心方法,合理确定静载试验加载量对保障桩基安全至关重要。文章对相关规范中单桩静载试验加载量取值要求进行阐述,针对常规加载量按照单桩承载力特征值两倍取值的适用性问题,对4种特殊条件下的桩基进行受力分析,并结合具体案例展开研究,最终提出4种特殊条件下单桩静载试验加载量的取值建议。研究表明:常规按单桩承载力特征值两倍确定加载量的方式,在文中的特殊条件下会降低工程桩使用阶段安全度,研究提出的取值建议能为类似特殊条件下单桩静载试验提供参考依据。 展开更多
关键词 静载试验 最大加载量 负摩阻力 抗拔桩 复合地基
原文传递
基于机器学习的爆炸荷载下RC板最大位移响应分析
14
作者 于晓辉 陈玉琛 代旷宇 《建筑科学与工程学报》 北大核心 2026年第1期85-94,共10页
收集既有试验及数值模拟结果,建立了包含491种钢筋混凝土(RC)板在爆炸荷载作用下的位移响应数据库。采用板的长度、宽度、厚度、混凝土抗压强度、钢筋屈服强度、配筋率、边界条件、板的类型、爆炸距离和爆炸当量10个影响因素作为输入参... 收集既有试验及数值模拟结果,建立了包含491种钢筋混凝土(RC)板在爆炸荷载作用下的位移响应数据库。采用板的长度、宽度、厚度、混凝土抗压强度、钢筋屈服强度、配筋率、边界条件、板的类型、爆炸距离和爆炸当量10个影响因素作为输入参数,采用3类共9种机器学习方法,分别建立了RC板在爆炸荷载下最大位移响应预测模型。采用可解释性机器学习方法,通过特征重要性分析、单因素部分依赖分析及交互性依赖分析,对所建立的机器学习模型进行解释,并对RC板在爆炸荷载下最大位移响应的影响因素的重要性进行了分析。结果表明:基于粒子群优化-极端梯度增强方法(PSO-XGBoost)的预测模型精度最高,且精度高于规范推荐的等效单自由度模型结果;在所考虑的影响因素中,爆炸当量、爆炸距离、板的厚度及配筋率对RC板在爆炸荷载作用下的最大位移响应影响最显著;RC板的抗爆设计应保证最小板厚达到150 mm,最小配筋率达到1.5%,且混凝土强度应达到50 MPa。 展开更多
关键词 RC板 爆炸荷载 最大位移响应 可解释性机器学习 PSO-XGBoost方法
在线阅读 下载PDF
下蹲动作中不同深度和负荷对膝关节力学和周围肌肉力量特征的影响
15
作者 闫相宁 陈雷 +2 位作者 陈永欢 王超 李小生 《中国组织工程研究》 北大核心 2026年第9期2236-2247,共12页
背景:在体育运动中下蹲有着多种变式及技术,不同的下蹲方法会对膝关节力学产生不同的影响,已有的研究成果中缺乏不同深度和负荷对下蹲过程中膝关节力学变化特征的充分探讨。目的:探讨不同深度下蹲(浅、平、深蹲)在3种负荷(85%,50%,0%一... 背景:在体育运动中下蹲有着多种变式及技术,不同的下蹲方法会对膝关节力学产生不同的影响,已有的研究成果中缺乏不同深度和负荷对下蹲过程中膝关节力学变化特征的充分探讨。目的:探讨不同深度下蹲(浅、平、深蹲)在3种负荷(85%,50%,0%一次最大蹲起质量)下的膝关节生物力学变化特征,从而为下蹲训练选择不同深度及负荷提供科学依据。方法:利用高速摄像机(Sony)、三维测力台(Kistler)和肌电仪(Noraxon)同步采集15名男性受试者进行不同深度和负荷下蹲时的运动学、动力学和肌电数据,使用逆向动力学、生物力学肌骨模型和优化算法计算膝关节力学和下肢肌群用力大小,最后采用双因素方差分析不同深度和负荷条件下的差异性。结果与结论:①负荷对膝关节力矩主效应显著(P<0.01),浅、平、深3种下蹲方式均在0%负荷状态有着最小的膝关节力矩;②负荷对胫股关节力、髌股关节力和十字交叉韧带力的主效应显著(P<0.01);随着下蹲深度的增加,胫股关节力、髌股关节力和十字交叉韧带力变化曲线出现双峰状趋势;③负荷对股四头肌力、腘绳肌力和腓肠肌力的主效应显著(P<0.01);50%负荷有着最大的股四肌力,腘绳肌力和腓肠肌力在85%负荷为最大;随着深度的增加,股四头肌和腘绳肌肌力变化呈现双峰趋势,而腓肠肌肌力总体呈现先减小后增大趋势;④膝关节各力学指标随着负荷的增加而增加,但50%和85%负荷之间差异较小;3种深度的下蹲在50%负荷下均出现最大的髌股关节力和股四头肌力;后交叉韧带力、腘绳肌力与腓肠肌力均在85%负荷下达到最高值,下蹲深度的增加对后交叉韧带受力无明显影响;当目的是最大化发展肌力进行负重下蹲时,推荐使用50%负荷平蹲,但要考虑其会带来较大的关节力和韧带力。 展开更多
关键词 深蹲 下蹲 膝关节 负荷 一次最大蹲起质量 逆动力学 EMG-driven 生物力学
在线阅读 下载PDF
气象因素对遂宁地区日最大电力负荷影响的初步研究
16
作者 唐沛 汪洋 +1 位作者 袁静 陆鸿彬 《成都信息工程大学学报》 2026年第2期223-228,共6页
为研究遂宁市电网最大电力负荷在不同时间尺度上的变化特征及其与气象因子的相关性,利用遂宁市2021-2023年每日逐15min电力负荷数据和遂宁市本站同期的气象要素观测数据,采用最小二乘法将气象负荷从总负荷中剔除后进行探讨。研究得出:20... 为研究遂宁市电网最大电力负荷在不同时间尺度上的变化特征及其与气象因子的相关性,利用遂宁市2021-2023年每日逐15min电力负荷数据和遂宁市本站同期的气象要素观测数据,采用最小二乘法将气象负荷从总负荷中剔除后进行探讨。研究得出:2021-2023年,遂宁地区逐日最大电力负荷呈现与气象条件紧密相关的显著季节性特征、夏冬双峰型态和逐年增长趋势。夏季和冬季是极端用电负荷出现的主要时段,夏季尤为显著(占比高达88%)。夏季8月更是极端用电负荷发生最频繁的月份(占比38%)。将日最高气温划分为4段后得出气温对气象负荷影响最为显著,特别是当日最高气温≥32℃时气象负荷与气温的相关性达到最高。 展开更多
关键词 日最大电力负荷 气象负荷 气象因子 相关性
在线阅读 下载PDF
工作姿势和负荷组合对上肢疲劳交互影响效应的幅频联合分析
17
作者 薛恩凯 徐红旗 《中国组织工程研究》 北大核心 2026年第16期4115-4124,共10页
背景:上肢工作相关肌肉骨骼疾患因对个人健康和社会经济的危害而备受关注,而肌肉疲劳是主要诱因。目的:通过幅频联合分析法探讨姿势和负荷交互效应对静态上肢作业中肌肉疲劳特征的影响,为上肢工作相关肌肉骨骼疾患的预防提供多维度生物... 背景:上肢工作相关肌肉骨骼疾患因对个人健康和社会经济的危害而备受关注,而肌肉疲劳是主要诱因。目的:通过幅频联合分析法探讨姿势和负荷交互效应对静态上肢作业中肌肉疲劳特征的影响,为上肢工作相关肌肉骨骼疾患的预防提供多维度生物力学依据。方法:14名健康受试者执行肩关节前屈20°,40°,60°的静态任务,任务负荷设置为其最大重复次数(1RM)的10%,30%和50%。同步采集表面肌电信号及Borg主观疲劳感知评估量表数据。采用幅频联合分析计算均方根斜率和中位频率斜率量化肌肉疲劳程度;应用配对样本t检验分析疲劳前后的疲劳状态占比;采用方差分析评估姿势、负荷及其交互效应对疲劳状态占比的影响。结果与结论:①姿势-负荷组合会显著影响作业耐受性(P<0.05),60°50%最大重复次数组合最大保持时间最短(P<0.001);②特定组合下疲劳前后肌肉疲劳状态改变:20°10%最大重复次数组合下,冈上肌和斜方肌上部疲劳状态占比显著下降(P<0.05);40°10%最大重复次数组合下,斜方肌上部疲劳状态占比差异极显著(P<0.01);③姿势与负荷对肌肉疲劳的影响相互独立,在20°姿势下,三角肌前束的疲劳占比在10%最大重复次数与30%最大重复次数、10%最大重复次数与50%最大重复次数的负荷对比中有显著性差异(P<0.05);而在10%最大重复次数负荷条件下,三角肌前束及中束的疲劳占比仅在20°与60°角度间、在疲劳前与全程阶段表现出显著性差异(P<0.05);④姿势与负荷无显著交互效应(P>0.05);⑤提示高负荷与高角度显著加速肌肉疲劳;姿势与负荷独立影响疲劳进程,二者交互效应不显著;幅频联合分析对于姿势与负荷影响下的肌肉疲劳特征敏感性有限。 展开更多
关键词 肌肉骨骼疾患 上肢疲劳 工作姿势 外部负荷 交互影响 最大保持时间 幅频联合分析
暂未订购
立式容器腿式支座设计中几个问题的讨论
18
作者 周淑敏 《石油化工设备技术》 2026年第1期18-25,I0001,共9页
文章对立式容器腿式支座设计中的若干问题进行了探讨.首先,对腿式支座的受力情况进行了详细分析,并推导出由弯矩引起的垂直载荷的计算公式,同时,通过严格的几何推导,得到了垂直载荷计算中需要用到的腿式支座地脚螺栓中心圆直径Db这一参... 文章对立式容器腿式支座设计中的若干问题进行了探讨.首先,对腿式支座的受力情况进行了详细分析,并推导出由弯矩引起的垂直载荷的计算公式,同时,通过严格的几何推导,得到了垂直载荷计算中需要用到的腿式支座地脚螺栓中心圆直径Db这一参数的精确求解公式,并利用VisualBasic.NET语言开发了相应的辅助计算软件.此外,文章还指出了SW6—2011v5.0计算程序中的一些错误,可为设计人员更好地理解腿式支座计算方法并进行非标腿式支座设计提供帮助. 展开更多
关键词 腿式支座 非标设计 最大垂直载荷 地震载荷 地脚螺栓中心圆直径 精确解 软件开发
在线阅读 下载PDF
基于改进近似最速下降学习的工业机械臂鲁棒控制
19
作者 陈斌星 王泽锴 《机械设计与制造工程》 2026年第1期49-52,共4页
为了进一步提高工业机械臂在变负载工况下的控制精度,提出了一种基于改进近似最速下降学习的机械臂鲁棒控制方法。在分析机械臂空间状态模型的基础上,以改进近似最速下降学习方法为基础,设计了一种具有自调节能力的鲁棒控制方法。变负... 为了进一步提高工业机械臂在变负载工况下的控制精度,提出了一种基于改进近似最速下降学习的机械臂鲁棒控制方法。在分析机械臂空间状态模型的基础上,以改进近似最速下降学习方法为基础,设计了一种具有自调节能力的鲁棒控制方法。变负载工况仿真结果表明,相较于卷积神经网络(CNN)控制器,自适应鲁棒控制器可以实现模型非线性估算,有助于控制器的扰动补偿和估算,显著增强鲁棒性,且适用于各种负载工况。试验结果表明,负载工况变化对迭代线性调节控制存在显著影响,而所提的自适应鲁棒控制具有良好鲁棒性,其跟踪误差仅为迭代线性调节控制的1/2左右,大幅提升了模型的跟踪精度。 展开更多
关键词 工业机械臂 鲁棒控制 近似最速下降 变负载
在线阅读 下载PDF
航空网络级联失效节点负载分配研究
20
作者 王国保 杨红刚 +2 位作者 马金龙 谢本凯 王肖艳 《物流科技》 2026年第7期38-42,共5页
针对实际航空网络机场节点对负载具备一定冗余,文章提出一种考虑节点容量的负载分配方法,首先,定义网络的节点过载系数和容量模型,对航空网络的级联失效过程进行建模;其次,定义正常节点、过载节点和失效节点三种节点负载状态,根据节点... 针对实际航空网络机场节点对负载具备一定冗余,文章提出一种考虑节点容量的负载分配方法,首先,定义网络的节点过载系数和容量模型,对航空网络的级联失效过程进行建模;其次,定义正常节点、过载节点和失效节点三种节点负载状态,根据节点不同负载状态选择不同的负载分配方式。通过仿真分析航空网络在三种攻击方式下网络最大连通子图比例的下降情况,研究发现,随着攻击节点的增多,网络最大连通子图的比例逐渐降低,但与传统负载分配方法相比,基于临界容量的负载重分方法可以有效减缓网络最大连通子图比例的下降趋势,提高网络在级联失效时的稳定性。 展开更多
关键词 航空网络 级联失效 负载分配 最大连通子图
在线阅读 下载PDF
上一页 1 2 43 下一页 到第
使用帮助 返回顶部