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Arabidopsis AGC protein kinases IREH1 and IRE3 control root skewing 被引量:2
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作者 Xiaozhen Yue Zhiai Guo +2 位作者 Teng Shi Lizhen Song Youfa Cheng 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2019年第5期259-267,共9页
AGC protein kinases play important roles in plant growth and development.Several AGC kinases in Arabidopsis have been functionally characterized.However,the"AGC Other"subfamily,including IRE,IREH1,IRE3 and I... AGC protein kinases play important roles in plant growth and development.Several AGC kinases in Arabidopsis have been functionally characterized.However,the"AGC Other"subfamily,including IRE,IREH1,IRE3 and IRE4,has not been well understood.Here,we reported that ireh1 mutants displayed a root skewing phenotype,which can be enhanced by ire3 mutation.IREH1 and IRE3 were expressed in roots,consistent with their function in controlling root skewing.The fluorescence intensities of the microtubule marker KNpro:EGFP-MBD were decreased in ireh1,ire3 and ireh1 ire3 mutants compared to wild type.The microtubule arrangements in ireh1 and ireh1 ire3 mutants were also altered.IREH1 physically interacted with IRE3 in vitro and in planta.Thus,our findings demonstrate that IREH1 and IRE3 protein kinases play important roles in controlling root skewing,and maintaining microtubule network in Arabidopsis. 展开更多
关键词 AGC KINASES IREH1 IRE3 ROOT skewing MICROTUBULE ARABIDOPSIS
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Sliding mode control design for oblique wing aircraft in wing skewing process 被引量:2
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作者 Ting YUE Zijian XU +1 位作者 Lixin WANG Tong WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2019年第2期263-271,共9页
When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting... When the wing of Oblique Wing Aircraft(OWA) is skewed, the center of gravity, inertia and aerodynamic characteristics of the aircraft all significantly change, causing an undesirable flight dynamic response, affecting the flying qualities, and even endangering the flight safety. In this study,the dynamic response of an OWA in the wing skewing process is simulated, showing that the threeaxis movements of the OWA are highly coupled and present nonlinear characteristics during the wing skewing. As the roll control efficiency of the aileron decreases due to the shortened control arm in an oblique configuration, the all-moving horizontal tail is used for additional roll and the control allocation is performed based on minimum control energy. Given the properties of pitchroll-yaw coupling and control input and state coupling, and the difficulty of establishing an accurate aerodynamic model in the wing skewing process due to unsteady aerodynamic force, a multi-loop sliding mode controller is formulated by the time-scale separation method. The closed-loop simulation results show that the asymmetric aerodynamics can be balanced and that the velocity and altitude of the aircraft maintain stable, which means that a smooth transition is obtained during the OWA's wing skewing. 展开更多
关键词 DECOUPLING Dynamic response OBLIQUE WING AIRCRAFT Sliding mode control WING skewing PROCESS
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Influence of Skewing Design for Reduction of Force Ripples in DSL-SynRM using 3D FEA 被引量:2
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作者 Anusha Vadde Sudha B 《CES Transactions on Electrical Machines and Systems》 CSCD 2019年第4期397-402,共6页
Double Sided Linear Synchronous Reluctance Motors(DSL-SynRM)are being increasingly used in high force density applications.The force ripples are one of the major issue in machine which is due to nonlinear nature of cu... Double Sided Linear Synchronous Reluctance Motors(DSL-SynRM)are being increasingly used in high force density applications.The force ripples are one of the major issue in machine which is due to nonlinear nature of current in the machines.This paper focuses on the reduction of force ripples for increasing the force density of the motor.In order to reduce the force ripples,DSL-SynRM with a skewed translator is proposed.The proposed structure is designed and developed by using computational magnetic tools.This concept is effective for reduction of the force ripples and improves the force density of the machine.The proposed design has been reduced the percentage of force ripples by 21.62%,improved the force density by 10.32 N/mm³and efficiency by 0.89%. 展开更多
关键词 DSL-SynRM force density FORCE force ripple skewing FEA
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Analysis and evaluation of electromagnetic vibration and noise in permanent magnet synchronous motor with rotor step skewing 被引量:13
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作者 DONG QiChao LIU XinTian +2 位作者 QI HongZhong SUN Chao WANG YanSong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2019年第5期839-848,共10页
In this paper, a multi-physics simulation model capable of electromagnetic noise prediction is established, and the effectiveness of the established simulation model in predicting and evaluating electromagnetic noise ... In this paper, a multi-physics simulation model capable of electromagnetic noise prediction is established, and the effectiveness of the established simulation model in predicting and evaluating electromagnetic noise is verified. Based on the verified motor model, a rotor step skewing model which can affect electromagnetic noise is proposed, and the influence of the skewing angle on electromagnetic noise is investigated in detail. By studying the spectral characteristics of the low-order radial magnetic force which has a great influence on electromagnetic noise, the distribution of electromagnetic noise characteristics of the permanent magnet synchronous motor(PMSM) with or without the rotor step skewing is compared and analyzed. Therefore, it lays a technological foundation for predicting and suppressing the electromagnetic vibration noise of electric vehicle(EV) driving motor in the electromagnetic design. 展开更多
关键词 PMSM ELECTROMAGNETIC noise STEP skewing MULTI-PHYSICS simulation model spectrum analysis
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Modeling the frictional torque of a dry-lubricated tapered roller bearing considering the roller skewing 被引量:4
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作者 Chi ZHANG Le GU +1 位作者 Yuze MAO Liqin WANG 《Friction》 SCIE CSCD 2019年第6期551-563,共13页
In this paper, an equation for the calculation of the frictional torque of a dry-lubricated tapered roller bearing(TRB) is provided in which the effect of the roller skewing is emphasized. Calculations were performed ... In this paper, an equation for the calculation of the frictional torque of a dry-lubricated tapered roller bearing(TRB) is provided in which the effect of the roller skewing is emphasized. Calculations were performed to investigate the effect of the roller skewing on the torque of dry-lubricated TRB for two representative preload methods, that is, axial force preload and axial displacement preload. The results show that a proper roller skewing angle under axial force preload benefits the reduction of the TRB torque. However, the roller skewing angle should not exceed a certain critical value;otherwise, it will cause a steep rise in the TRB torque. Finally, the critical value of the roller skewing angle as a function of the friction coefficient and cage pocket clearance is presented. The developed torque model provides a tool for the internal design and torque optimization of dry-lubricated TRBs. 展开更多
关键词 tapered roller bearing frictional torque roller skewing dry lubrication
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Seed size distributions of fleshy-fruited species are more right-skewed compared to that of dry-fruited species
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作者 Xiaoyan Hu Jinyu Zhang Bo Wang 《Plant Diversity》 2025年第3期522-525,共4页
Seed dispersal is a pivotal process in seed plant life cycle,owing to its effects on seed germination,seedling survival,population recruitment,and diversity maintenance in the entire community(Howe and Smallwood,1982;... Seed dispersal is a pivotal process in seed plant life cycle,owing to its effects on seed germination,seedling survival,population recruitment,and diversity maintenance in the entire community(Howe and Smallwood,1982;Rogers et al.,2021).There are diverse dispersal modes,such as anemochory(wind-driven dispersal),hydrochory(water-mediated dispersal),autochory(self-dispersal),and zoochory,which relies on a diverse array of animals for seed dispersal(Howe and Smallwood,1982).It is widely known that these varying dispersal modes impose selective pressures on many seed and fruit traits,especially the seed size,a key trait which is associated with multiple stages of the life cycle of plants,such as dispersal,germination,and establishment,particularly during early development(Leishman et al.,2000). 展开更多
关键词 Fruit type Intraspecific variation Seed dispersal Seed mass SKEWNESS
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QHF-CS: Quantum-Enhanced Heart Failure Prediction Using Quantum CNN with Optimized Feature Qubit Selection with Cuckoo Search in Skewed Clinical Data
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作者 Prasanna Kottapalle Tan Kuan Tak +2 位作者 Pravin Ramdas Kshirsagar Gopichand Ginnela Vijaya Krishna Akula 《Computers, Materials & Continua》 2025年第8期3857-3892,共36页
Heart failure prediction is crucial as cardiovascular diseases become the leading cause of death worldwide,exacerbated by the COVID-19 pandemic.Age,cholesterol,and blood pressure datasets are becoming inadequate becau... Heart failure prediction is crucial as cardiovascular diseases become the leading cause of death worldwide,exacerbated by the COVID-19 pandemic.Age,cholesterol,and blood pressure datasets are becoming inadequate because they cannot capture the complexity of emerging health indicators.These high-dimensional and heterogeneous datasets make traditional machine learning methods difficult,and Skewness and other new biomarkers and psychosocial factors bias the model’s heart health prediction across diverse patient profiles.Modern medical datasets’complexity and high dimensionality challenge traditional predictionmodels like SupportVectorMachines and Decision Trees.Quantum approaches include QSVM,QkNN,QDT,and others.These Constraints drove research.The“QHF-CS:Quantum-Enhanced Heart Failure Prediction using Quantum CNN with Optimized Feature Qubit Selection with Cuckoo Search in Skewed Clinical Data”system was developed in this research.This novel system leverages a Quantum Convolutional Neural Network(QCNN)-based quantum circuit,enhanced by meta-heuristic algorithms—Cuckoo SearchOptimization(CSO),Artificial BeeColony(ABC),and Particle SwarmOptimization(PSO)—for feature qubit selection.Among these,CSO demonstrated superior performance by consistently identifying the most optimal and least skewed feature subsets,which were then encoded into quantum states for circuit construction.By integrating advanced quantum circuit feature maps like ZZFeatureMap,RealAmplitudes,and EfficientSU2,the QHF-CS model efficiently processes complex,high-dimensional data,capturing intricate patterns that classical models overlook.The QHF-CS model improves precision,recall,F1-score,and accuracy to 0.94,0.95,0.94,and 0.94.Quantum computing could revolutionize heart failure diagnostics by improving model accuracy and computational efficiency,enabling complex healthcare diagnostic breakthroughs. 展开更多
关键词 Accuracy quantum machine learning heart failure PREDICTION cuckoo search optimization(CSO) skewed clinical data quantum convolutional circuit
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Characterized Behaviors of Black Hole Thermodynamics in the Supercritical Region
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作者 Zi-Qiang Zhao Zhang-Yu Nie +1 位作者 Jing-Fei Zhang Xin Zhang 《Chinese Physics Letters》 2025年第10期331-335,共5页
The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the an... The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics. 展开更多
关键词 scaled variance supercritical region widom lineassociated analysis characteristic lines crossover behaviors SKEWNESS comprehension universal thermodynamic behaviors examining characteristics black hole systems black hole thermodynamics
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一种新型Skew Tent映射的混沌混合优化算法 被引量:17
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作者 江善和 王其申 江巨浪 《控制理论与应用》 EI CAS CSCD 北大核心 2007年第2期269-273,共5页
针对已有的混沌优化算法几乎都是利用Logistic映射作为混沌序列发生器,而该混沌序列的概率密度函数呈两头多、中间少的切比雪夫型的分布性质,不利于搜索的效率和能力,为此,首先构造一种新型混沌映射序列发生器—Skew Tent映射并结合迭... 针对已有的混沌优化算法几乎都是利用Logistic映射作为混沌序列发生器,而该混沌序列的概率密度函数呈两头多、中间少的切比雪夫型的分布性质,不利于搜索的效率和能力,为此,首先构造一种新型混沌映射序列发生器—Skew Tent映射并结合迭代优化特点加以改进,然后分析了它的混沌特性.其次,将改进的混沌映射与Alopex启发算法相结合,充分发挥Alopex算法的快速搜索能力和混沌优化全局寻优的特性,提出一种混沌混合优化算法,提高了算法的收敛速度和有效搜索全局最优解.最后,仿真算例验证了该算法的有效性和Skew Tent混沌映射的应用前景. 展开更多
关键词 LOGISTIC映射 SKEW TENT映射 ALOPEX算法 混沌混合优化 全局最优
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银行间同业拆放利率风险度量:基于EGARCH-SGED模型的实证分析 被引量:11
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作者 杨爱军 刘晓星 蔡则祥 《金融理论与实践》 CSSCI 北大核心 2012年第8期8-12,共5页
根据上海银行间同业拆放利率(SHIBOR)数据的基本特性,分析SHIBOR收益率序列呈尖峰厚尾、偏态和波动集聚等特征,利用EGARCH模型来刻画收益率的波动性,同时利用Skew-GED(SGED)分布来描述收益率的概率分布特征,构建EGARCH-SGED模型来测度SH... 根据上海银行间同业拆放利率(SHIBOR)数据的基本特性,分析SHIBOR收益率序列呈尖峰厚尾、偏态和波动集聚等特征,利用EGARCH模型来刻画收益率的波动性,同时利用Skew-GED(SGED)分布来描述收益率的概率分布特征,构建EGARCH-SGED模型来测度SHIBOR收益率的风险价值,并与GED和Skew-t分布下的EGARCH模型的风险测度能力进行了比较。研究结果表明,与其他两类模型相比较而言,EGARCH-SGED模型能更好地描述SHIBOR收益率特性,并且能够显著提高风险价值预测的准确性。 展开更多
关键词 EGARCH模型 Skew—GED 风险价值 后验测试
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基于ARMA-APARCH-SGED模型的原油价格风险度量研究 被引量:7
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作者 杨爱军 肖振宇 《统计与信息论坛》 CSSCI 2011年第8期35-41,共7页
从原油现货市场收益率的特征分析着手,为了更好地描述原油现货市场收益率的尖峰厚尾、偏态和波动集聚等特性,利用APARCH模型来刻画收益率的波动性,同时利用Skew GED(SGED)分布来描述收益率的概率分布特征;进而运用ARMA-APARCH-SGED模型... 从原油现货市场收益率的特征分析着手,为了更好地描述原油现货市场收益率的尖峰厚尾、偏态和波动集聚等特性,利用APARCH模型来刻画收益率的波动性,同时利用Skew GED(SGED)分布来描述收益率的概率分布特征;进而运用ARMA-APARCH-SGED模型对原油现货市场收益率的VaR进行估计和分析,并与基于Skew-t和GED分布的ARMA-APARCH模型进行比较。通过返回检验,结果表明,AR-MA-APARCH-SGED模型能更加准确地度量原油现货市场的风险价值。 展开更多
关键词 SKEW GED APARCH 返回检验
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AFDX网络冗余管理技术分析 被引量:2
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作者 徐进 黄玉港 +2 位作者 王静玲 田瑜 张小龙 《电子科技》 2017年第3期101-103,共3页
为实现AFDX以太网的冗余管理功能,分析了AFDX网络冗余管理技术和冗余管理接收与发送帧过程中的完整性检查以及冗余管理配置参数最大偏移参数(Skew Max)。文中根据完整性检查来分析顺序号在接收端与发送端的作用以及冗余管理配置参数,设... 为实现AFDX以太网的冗余管理功能,分析了AFDX网络冗余管理技术和冗余管理接收与发送帧过程中的完整性检查以及冗余管理配置参数最大偏移参数(Skew Max)。文中根据完整性检查来分析顺序号在接收端与发送端的作用以及冗余管理配置参数,设计了冗余管理算法。并对设计的冗余管理算法进行了仿真验证,结果表明,该设计的冗余管理算法可靠准确,设计符合ARINC664 Part7规定的协议要求。 展开更多
关键词 AFDX 完整性检查 SKEW MAX 冗余管理 冗余管理算法
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基于修正Sharpe指数的我国开放式基金业绩评价研究 被引量:4
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作者 于天军 田金信 汪洋 《中国软科学》 CSSCI 北大核心 2010年第7期175-183,共9页
国内外大量实证研究发现基金收益率呈明显的尖峰、厚尾性和有偏性的非正态分布。针对Sharpe指数前提假设是收益率服从正态分布及使用标准差来度量投资风险的缺陷。本文提出用能更好的刻画投资基金收益率分布的非对称性和尖峰、厚尾性的S... 国内外大量实证研究发现基金收益率呈明显的尖峰、厚尾性和有偏性的非正态分布。针对Sharpe指数前提假设是收益率服从正态分布及使用标准差来度量投资风险的缺陷。本文提出用能更好的刻画投资基金收益率分布的非对称性和尖峰、厚尾性的Skewed-t分布来拟合基金收益率分布。在此基础上分别给出了基于Skewed-t分布标准差和Skewed-t分布下的FIGARCH-SKST模型测算的VaR值的修正夏普指数;然后对22只开放式基金数据进行了实证分析。结果表明,基于Skewed-t分布修正的Sharpe指数是有效的。 展开更多
关键词 基金业绩评价 Skewed—t分布 FIGARCH—SKST模型 Sharpe指数
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Scale effects on non-cavitation hydrodynamics and noise of highly-skewed propeller in wake flow 被引量:1
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作者 杨琼方 王永生 张明敏 《Journal of Southeast University(English Edition)》 EI CAS 2013年第2期162-169,共8页
Regarding the scale effects on propeller's noncavitation hydrodynamics and hydroacoustics, three similar 7bladed highly-skewed propellers in the wake flow are addressed with diameters of 250, 500 and 1 000 mm, respec... Regarding the scale effects on propeller's noncavitation hydrodynamics and hydroacoustics, three similar 7bladed highly-skewed propellers in the wake flow are addressed with diameters of 250, 500 and 1 000 mm, respectively. The discrete line-spectrum noise and its standardized spectrum level scaling law, together with the total sound pressure level are analyzed. The non-cavitation noise predictions are completed by both the frequency domain method and the time domain method. As a fluctuated noise source, the time-dependent fluctuated pressure and normal velocity distribution on propeller blades are obtained by the unsteady Reynolds-averaged Navier-Stokes ( URANS ) simulation. Results show that the pressure coefficient distribution of three propellers on the 0.7R section is nearly superposed under the same advance ratio. The periodic thrust fluctuation of three propellers can exactly reflect the tonal components of the axial passing frequency (APF) and the blade passing frequency (BPF), and the fluctuation enhancement from the small to the middle propeller at the BPF is greater than that from the middle to the big one. By the two noise prediction methods, the increment of the total sound pressure level from the small to the big propeller differs by 2.49 dB. Following the standardized scaling law, the spectrum curves of the middle and big propellers are nearly the same while significantly differing from the small one. The increment of both the line-spectrum level and the total sound pressure increases with the increase in diameter. It is suggested that the model scale of the propeller should be as large as possible in engineering to reduce the prediction error of the empirical scalin~ law and weaken the scale effects. 展开更多
关键词 highly skewed propeller non-cavitation noise scale effects frequency domain time domain
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基于有限状态混沌映射的扩频序列(英文) 被引量:1
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作者 罗伟民 Wang Muzhong 丘水生 《华南理工大学学报(自然科学版)》 EI CAS CSCD 北大核心 2002年第1期22-26,共5页
基于skewtent映射 ,提出了一类离散化的有限状态混沌映射 ,它允许精确的数值计算 ,没有舍入误差 .通过选择合适的参数 ,该映射能产生全周期长度的序列 .实验表明 ,归一化的序列平均周期对计算机精度不敏感 ,生成的二进制序列具有良好的... 基于skewtent映射 ,提出了一类离散化的有限状态混沌映射 ,它允许精确的数值计算 ,没有舍入误差 .通过选择合适的参数 ,该映射能产生全周期长度的序列 .实验表明 ,归一化的序列平均周期对计算机精度不敏感 ,生成的二进制序列具有良好的相关性能 ,是扩频码的良好选择。 展开更多
关键词 扩频序列 有限精度效应 SKEW TENT映射 相关性能 有限状态混沌映射 扩频码
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Determination of Salinity in Fluid Inclusions with Laser Raman Spectroscopy Technique 被引量:1
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作者 Seyed Javad Moghaddasi 《Journal of Earth Science》 SCIE CAS CSCD 2000年第4期34-37,共4页
A preliminary study was conducted to outline the laser Raman spectroscopy technique for determination of salinity in the aqueous phase in fluid inclusions. The skewing parameters of the Raman profiles of the calibrat... A preliminary study was conducted to outline the laser Raman spectroscopy technique for determination of salinity in the aqueous phase in fluid inclusions. The skewing parameters of the Raman profiles of the calibration solutions determined were used to derive a calibration curve for the estimation of the equivalent mass fraction NaCl in aqueous solutions. This technique was also verified in the analysis of the natural fluid inclusions from Tongshankou porphyry Cu (Mo) deposit, Hubei Province, China. Although the analyses on the natural fluid inclusions are limited, an acceptable agreement has been reached on the salinities, for most fluid inclusions, determined by the Raman spectroscopy and microthermometry techniques, indicating the reliability of the Raman technique for determination of salinity in fluid inclusion studies. 展开更多
关键词 Raman spectroscopy fluid inclusion SALINITY skewing parameter microthermometry.
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Detection of mechanical stress in the steel structure of a bridge crane 被引量:1
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作者 Leopold Hrabovsky Daniel Cepica Karel Frydrysek 《Theoretical & Applied Mechanics Letters》 CSCD 2021年第6期320-329,共10页
A significant negative aspect in the operation of bridge-type cranes are the technical problems associated with wear of the wheels and the crane track,which causes crane skewing.The main causes of crane skewing includ... A significant negative aspect in the operation of bridge-type cranes are the technical problems associated with wear of the wheels and the crane track,which causes crane skewing.The main causes of crane skewing include unevenness of the crane track,unequal loading of the traction drives depending on the position of the crane trolley,slips and different sizes of travel wheels and combinations of these causes.Firstly,this paper presents a design solution that can be used to detect the magnitude of mechanical stress and deformation of the steel structure of the crane,caused by the effects of skewing.The mechanical stress generated by the transverse forces of the deformed geometric shape of the crane bridge structure is recorded by mechanical stress detectors installed in the inner corners of the crane bridge.The resulting electrical signal from element mechanical voltage detectors,loaded by axial forces,can be used for feedback control of separate crane travel drives controlled by frequency converters.Secondly,this paper presents the calculation of the lateral transverse forces according to CSN 270103 and the determination of the values of mechanical stresses of the deformed steel structure of the crane bridge of a two-girder bridge crane using the finite element method in the program MSC.MARC 2019.Finally,this paper presents the structural and strength design of mechanical stress detectors and the conclusions of laboratory tests of axial force loading of mechanical stress detectors on the test equipment.At the same time,it presents records of the measured axial forces acting in the mechanical stress detectors,arising from the deformation and warping of the crane bridge by the known magnitude of the axial force acting on the crossbeam and from the deformation of the crane bridge caused by the crane operating modes. 展开更多
关键词 Crane skewing Mechanical stress detector Mechanical stress FEM Overhead crane
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A New Clock-Driven ECO Placement Algorithm Based on Table-Lookup Delay Model
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作者 刘毅 洪先龙 +2 位作者 蔡懿慈 吴为民 Chung-Wen Albert Tsao 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第5期473-478,共6页
A new clock-driven ECO placement algorithm is pr es ented for standard-cell layout design based on the table-lookup delay model.It considers useful clock skew information in the placement stage.It also modifies the ... A new clock-driven ECO placement algorithm is pr es ented for standard-cell layout design based on the table-lookup delay model.It considers useful clock skew information in the placement stage.It also modifies the positions of cells locally to make better preparation for the clock routing . Experimental results show that with little influence to other circuit performa nce,the algorithm can improve permissible skew range distribution evidently. 展开更多
关键词 CLOCK-DRIVEN incremental placement useful skew permissibl e skew range
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基于Skewness纹理的北京城市化区域提取
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作者 李熙 关泽群 沈体雁 《安徽农业科学》 CAS 北大核心 2008年第17期7407-7409,7412,共4页
北京地区部分农作物和城市化区域的光谱属性接近,仅仅利用光谱信息无法有效地提取北京的城市化区域。提出了利用Skewness纹理区分农作物和城市化区域,结合光谱和高程信息可以有效提取城市化区域。经过大量的样本检验表明,引入Skewness... 北京地区部分农作物和城市化区域的光谱属性接近,仅仅利用光谱信息无法有效地提取北京的城市化区域。提出了利用Skewness纹理区分农作物和城市化区域,结合光谱和高程信息可以有效提取城市化区域。经过大量的样本检验表明,引入Skewness特征能够大幅度提高分类精度。 展开更多
关键词 ETM+ 遥感 纹理 建成区 SKEWNESS
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基于偏态分布的风险度量计算
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作者 王泓娜 宋立新 《大连理工大学学报》 EI CAS CSCD 北大核心 2012年第4期615-618,共4页
金融时间序列具有尖峰厚尾性,同时在股市中又存在着杠杆效应.对股票指数收盘价格的对数收益率序列建立ARMA-APARCH模型,在对数收益率序列分别满足Skewed-t分布和Skewed-GED的假设下,给出了在险价值及期望损失的计算方法.对t分布与Skewe... 金融时间序列具有尖峰厚尾性,同时在股市中又存在着杠杆效应.对股票指数收盘价格的对数收益率序列建立ARMA-APARCH模型,在对数收益率序列分别满足Skewed-t分布和Skewed-GED的假设下,给出了在险价值及期望损失的计算方法.对t分布与Skewed-t分布、GED与Skewed-GED分别进行对比性实证分析,结果表明,在两个偏态分布假设下计算得到的期望损失估计结果更为保守,更能够捕捉到股市的尾部风险. 展开更多
关键词 APARCH Skewed—t分布 Skewed—GED 在险价值 期望损失
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