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Statistical and Visual Evaluation of Artificial Neural Networks and Multiple Linear Regression Performances in Estimating Reference Crop Evapotranspiration for Mersin
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作者 Fatma Bunyan Unel Lutfiye Kusak +3 位作者 Murat Yakar Abdullah Sahin Hakan Dogan Fikret Demir 《Revue Internationale de Géomatique》 2025年第1期433-460,共28页
This study aimed to create a model for calculating the total reference crop evapotranspiration(ETo)in Mersin Province from May 2015 to 2020 and to generate maps using spatial analysis.Lemons from citrus play a signifi... This study aimed to create a model for calculating the total reference crop evapotranspiration(ETo)in Mersin Province from May 2015 to 2020 and to generate maps using spatial analysis.Lemons from citrus play a significant role inMersin’s agriculture,and because of lemons’sensitivity to temperature,ETo is essential for them.Itwas observed that the ETo value(EToPM)calculated using the Penman-Monteith(PM)method increased over the years.A model was developed using data from 36 Automated Weather Observing Systems(AWOS)in Mersin,Turkiye,which is located in a semi-arid climate zone.The model was created using Multiple Linear Regression(MLR)and artificial neural network(ANN)methods.The station climate data were divided into training and test datasets separately and collectively,and ETo values were estimated with different combinations using three scenarios and six model constructs.The dataset was divided into training(2015-2018)and testing(2019-2020).ANN1 andMLR1 are analyses of individual AWOS,while the other models are analyses of all AWOS together.The statistical performance analysis involved a comparison of the R2,Mean Absolute Error(MAE),Mean Absolute Percentage Error(MAPE),and RootMean Square Error(RMSE)values.The analysis results indicated that ANN1(0.9997,0.0105,0.2718%,and 0.0162,respectively)and ANN2(0.9958,0.0678,1.5341%,and 0.0864,respectively)models successfully predicted as statistical with both single and all AWOS.Themodels were visually evaluated using the Inverse DistanceWeighting(IDW)interpolationmethod,andmaps of plant water consumption were generated.The relationships between bothmodels and years in themonthly total ETo maps allowed for a clearer comparison. 展开更多
关键词 PENMAN-MONTEITH reference crop evapotranspiration multiple linear regression artificial neural networks IDWinterpolation
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A Method for Risky Multiple Attribute Decision Making with Four - dimensional Reference Point
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作者 DUAN Mingyuan YAN Ruixia 《International English Education Research》 2016年第12期22-25,共4页
A method based on cumulative prospect theory was proposed to solve risky multiple attribute decision making problems with Four -dimensional reference points. Considering the influence of different learning processes a... A method based on cumulative prospect theory was proposed to solve risky multiple attribute decision making problems with Four -dimensional reference points. Considering the influence of different learning processes and corresponding features on decision-making, a new reference-learning behavior is added, and a risk-based multiple-attribute decision-making method based on four-dimensional reference point cumulative prospect theory is proposed. Firstly, according to the cumulative prospect theory, the prospect value and the decision function value of the four reference points of learning, time, evaluation value and expected value are calculated respectively, and the cumulative prospect value matrix of each program dynamic is formed. Secondly,according to the WAA operalor, Maximize the stage weighting model to obtain the integrated cumulative prospect value. Finally, on the basis of this, the alternatives are sorted according to the size of the total cumulative prospect value, and compared with other methods, the validity and scientific of the proposed method are proved. 展开更多
关键词 Risk multiple attribute decision making Cumulative Prospect Theory Four-dimensional reference point
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Quantum-Mechanical Information Content of Multiples Hartree-Fock Solutions. The Multi-Reference Hartree-Fock Configuration Interaction Method
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作者 Luiz Augusto Carvalho Malbouisson Antonio Moreira de Cerqueira Sobrinho Micael Dias de Andrade 《Journal of Modern Physics》 2014年第7期543-548,共6页
The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction spac... The Hartree-Fock equation is non-linear and has, in principle, multiple solutions. The ωth HF extreme and its associated virtual spin-orbitals furnish an orthogonal base Bω of the full configuration interaction space. Although all Bω bases generate the same CI space, the corresponding configurations of each Bω base have distinct quantum-mechanical information contents. In previous works, we have introduced a multi-reference configuration interaction method, based on the multiple extremes of the Hartree-Fock problem. This method was applied to calculate the permanent electrical dipole and quadrupole moments of some small molecules using minimal and double, triple and polarized double-zeta bases. In all cases were possible, using a reduced number of configurations, to obtain dipole and quadrupole moments in close agreement with the experimental values and energies without compromising the energy of the state function. These results show the positive effect of the use of the multi-reference Hartree-Fock bases that allowed a better extraction of quantum mechanical information from the several Bω bases. But to extend these ideas for larger systems and atomic bases, it is necessary to develop criteria to build the multireference Hartree-Fock bases. In this project, we are beginning a study of the non-uniform distribution of quantum-mechanical information content of the Bω bases, searching identify the factors that allowed obtain the good results cited 展开更多
关键词 multiple HARTREE-FOCK SOLUTIONS QUANTUM MECHANICAL INFORMATION Content MULTI-reference Hartre-Fock Configuration Interaction Method
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Variations in Tomotherapy Beam Outputs: A Multiple-Institutional Investigation
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作者 Hidetoshi Shimizu Koji Sasaki +5 位作者 Kentaro Sugi Hiroshi Fukuma Tadashi Nakabayashi Taiki Isomura Hiroyuki Tachibana Takeshi Kodaira 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第1期87-99,共13页
This study aimed to determine variations in tomotherapy beam outputs at multiple institutions. Measurements were obtained at 22 radiotherapy institutions. The first parameter was the absolute dose to water (Dfmsrw, Qm... This study aimed to determine variations in tomotherapy beam outputs at multiple institutions. Measurements were obtained at 22 radiotherapy institutions. The first parameter was the absolute dose to water (Dfmsrw, Qmsr) in the machine-specific reference field (fmsr), which indicated a static field in the tomotherapy reference conditions defined by the International Atomic Energy Agency (IAEA) study group. The second measured parameter was the difference between the measured and the planed doses in the intensity modulated radiotherapy (IMRT) verification plans, which were created using a solid phantom by the vendor during tomotherapy apparatus installation to adjust the beam output. The IMRT verification plan error at each institution was defined as the systematic error of the beam output;Dfmsrw, Qmsr was subsequently modified. The Dfmsrw, Qmsr values of four institutions with a modified energy fluence per ideal open time (EFIOT) were lower than the values at other institutions. The mean value of all institutions except those four was 0.994 ± 0.013 Gy (range: 0.974 Gy, 1.017 Gy). When the Dfmsrw, Qmsr value was corrected by the IMRT verification error, this variation decreased. In addition, the mean IMRT verification errors in the TomoDirectTM and TomoHelicalTM modes with the TomoEDGETM mode were 1.2% ± 0.8% (range: -0.6%, 1.8%) and 0.2% ± 0.5% (range: -0.6%, 0.9%), respectively (p 展开更多
关键词 TOMOTHERAPY Machine-Specific reference Field multiple Institutions BEAM OUTPUT
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Theoretical Study on Divergence Problems of Single Reference Perturbation Theories
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作者 Jiang Yi Zhong-fu Xie Fei-wu Chen 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第5期597-602,共6页
Divergences of the single reference perturbation theories due to the addition of diffusion basis functions have been investigated for both closed-shell and open-shell molecular systems.It is found that the oscillatory... Divergences of the single reference perturbation theories due to the addition of diffusion basis functions have been investigated for both closed-shell and open-shell molecular systems.It is found that the oscillatory range of perturbation energies of open-shell systems increases as the spin multiplicity of systems changes from 2 to 4.Feenberg transformation is exploited to treat the divergence problems.It is found numerically that within the interval of Feenberg parameter there exists a minimum perturbation order at which the perturbation series become convergent.It is also found for the open-shell systems that the magnitude of the corresponding Feenberg parameter becomes larger as the spin multiplicity of the system of interest changes from 2 to 4. 展开更多
关键词 Single reference perturation theory DIVERGENCE Diffuse function Spin multiplicity Feenberg transformation
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双标多测法同时测定茯苓中13种三萜类成分的含量
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作者 丁婵 熊文惠 +5 位作者 厉晓 彭思源 龚婕 浦子牛 肖作为 崔培梧 《中成药》 北大核心 2026年第1期129-135,共7页
目的建立双标多测法同时测定茯苓中6α-羟基猪苓酸C、茯苓新酸B、去氢土莫酸、土莫酸、茯苓新酸A、3-表去氢茯苓酸、猪苓酸C、3-表去氢土莫酸、去氢茯苓酸、茯苓酸、松苓新酸、去氢齿孔酸、齿孔酸的含量。方法分析采用Agilent XDB-C_(18... 目的建立双标多测法同时测定茯苓中6α-羟基猪苓酸C、茯苓新酸B、去氢土莫酸、土莫酸、茯苓新酸A、3-表去氢茯苓酸、猪苓酸C、3-表去氢土莫酸、去氢茯苓酸、茯苓酸、松苓新酸、去氢齿孔酸、齿孔酸的含量。方法分析采用Agilent XDB-C_(18)(250 mm×4.6 mm,5μm)色谱柱;流动相水(含0.3%磷酸)-乙腈,梯度洗脱;体积流量1.0 mL/min;柱温25℃;检测波长242、203 nm。以6α-羟基猪苓酸C和茯苓酸为双标,双标线性校正法预测其他成分保留时间;以茯苓酸为内标,计算其他成分相对校正因子,计算其含量。结果13种成分在各自范围内线性关系良好(R^(2)≥0.9993),平均加样回收率99.77%~104.60%,RSD 0.16%~2.88%。双标线性校正法更准确,偏差更小。双标多测法与常规外标法所得结果无显著差异。结论该方法可实现茯苓中主要三萜类成分的快速分析,是该药材切实可行的整体质量评价方法。 展开更多
关键词 茯苓 三萜 含量测定 双标多测法 双标线性校正法
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基于多参考点线性MPC的类车机器人路径跟踪
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作者 白国星 刘飞 +3 位作者 孟宇 顾青 宋治玮 刘绍冲 《浙江大学学报(工学版)》 北大核心 2026年第4期679-689,共11页
针对传统类车机器人路径跟踪控制方法在精确性和实时性之间的矛盾,提出基于多参考点线性模型预测控制的方法(MRP-LMPC).该方法通过重新设定线性化展开点并修正差分模型,结合非线性与线性迭代预测获得非线性补偿量,再提取多个参考路径点... 针对传统类车机器人路径跟踪控制方法在精确性和实时性之间的矛盾,提出基于多参考点线性模型预测控制的方法(MRP-LMPC).该方法通过重新设定线性化展开点并修正差分模型,结合非线性与线性迭代预测获得非线性补偿量,再提取多个参考路径点,构建能够适应曲率突变的MRP-LMPC控制器.联合仿真验证表明,所提出的MRP-LMPC在U形路径上的最大横向位移误差为0.0971 m,在单车道变换路径上的最大横向位移误差为0.1185 m.在硬件在环实验中,在无定位误差的情况下,最大位移误差为0.1897 m;在有定位误差的情况下,最大位移误差为0.2486 m.与相同条件下的非线性预测控制(NMPC)相比,MRP-LMPC的精度损失较小,最大误差增加小于0.0949 m.与单参考点线性模型预测控制(SRP-LMPC)和比例积分微分(PID)控制器相比,MRP-LMPC精度优势显著.在实时性方面,所提方法在联合仿真中的最差工况下,平均求解时间为3.53 ms,在硬件在环测试中的最差工况下,平均求解时间为5.59 ms.在所有测试中,最大计算时间占控制周期的比例为44.15%.在相同工况下,相比NMPC,所提方法可将平均求解时间减少39.14%.综上,联合仿真和硬件在环测试的结果表明,MRPLMPC有效地平衡了精度和实时性能,计算速度比NMPC快,精度比PID和SRP-LMPC更高. 展开更多
关键词 路径跟踪控制 类车机器人 模型预测控制(MPC) 线性控制 多参考点
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全球金矿石标准物质研制及粒金效应研究进展
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作者 刘玖芬 杨理勤 +10 位作者 熊英 李志慧 刘佳 赵晓峰 王莹 邢莉圆 王斐然 李子奇 孙嘉潞 石环宇 刘淑亮 《岩矿测试》 北大核心 2026年第2期265-281,共17页
标准物质是衡量测试结果准确性的基准,国内外持续研制各类型标准物质以支撑样品测试质量控制、量值溯源和法律仲裁等工作。当前,中国金矿石有证标准物质在种类、定值元素覆盖及低品位段代表性等方面与实际需求存在显著差距,借鉴国际金... 标准物质是衡量测试结果准确性的基准,国内外持续研制各类型标准物质以支撑样品测试质量控制、量值溯源和法律仲裁等工作。当前,中国金矿石有证标准物质在种类、定值元素覆盖及低品位段代表性等方面与实际需求存在显著差距,借鉴国际金矿石标准物质研制经验(如类型丰富、定值元素多、低品位段占比高),有助于服务新一轮战略找矿突破。本文基于国内外资源共享平台大数据,系统梳理了全球金矿石标准物质研制现状和关键技术瓶颈。截至2025年6月,国外金矿石有证标准物质超160种,具有类型丰富、定值元素多、低品位段占比高(0.104×10^(-6)~1×10^(-6)区间占比40%)等特点,候选物涵盖绿岩、花岗岩、火山岩、变质岩、石英砾岩等多种岩矿石种类,定值元素涵盖Au、Ag、Cu、Mo、Sb、Al等共伴生元素;中国金矿石有证标准物质有74种,候选物金矿类型主要是石英脉型、蚀变岩型、卡林型3种,定值元素主要是Au或Au、Ag两个元素,多元素同步定值仅5种,低品位段占比小(0.2×10^(-6)~1×10^(-6)区间占比12%)。通过对比,揭示了中国的金矿石标准物质存在类型单一、定值元素局限、低品位覆盖不足等问题。深入分析金矿石加工各环节技术难题,本文指出“粒金效应”是制约标准物质种类丰富度的关键瓶颈,并论证了激光粒度分析法不适用于金矿石加工粒度检查。针对上述差距与挑战,本文建议:加强金矿石加工方法学(特别是针对粒金效应)与专用设备(如大型盘磨机、特种雷蒙磨)研发;系统研制中国典型成矿带系列金矿石标准物质;推行金与共伴生元素同步定值;重点布局边界品位至工业品位区间(尤其是低含量段)标准物质。着力解决因标准物质与实际样品基体差异导致的质控“失控”问题,为全球金矿勘查、选冶、贸易等全产业链提供坚实支撑。 展开更多
关键词 金矿石 标准物质 均匀性 粒金效应 多元素定值
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一种串列翼飞行器螺旋桨滑流效应影响研究
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作者 张迅 高经武 +3 位作者 李杰 杨亚超 杨宇 叶波波 《机械设计与制造工程》 2026年第4期73-78,共6页
针对串列翼飞行器螺旋桨滑流引发气动特性非线性变化的问题,提出基于多重参考系(MRF)模型的滑流效应高精度数值模拟方法。构建旋转坐标系下的雷诺平均纳维-斯托克斯(RANS)方程求解体系,采用压力基稳态求解器与标准壁面函数,通过离心力/... 针对串列翼飞行器螺旋桨滑流引发气动特性非线性变化的问题,提出基于多重参考系(MRF)模型的滑流效应高精度数值模拟方法。构建旋转坐标系下的雷诺平均纳维-斯托克斯(RANS)方程求解体系,采用压力基稳态求解器与标准壁面函数,通过离心力/科氏力等效旋转效应,实现滑流与机翼干扰的稳态耦合分析。动力测试台验证拉力仿真误差小于等于2%,扭矩误差小于等于8%。在4°攻角工况下,滑流使全机升力系数较无滑流状态提升31.6%,且前翼阻力在正攻角区显著增大(较后翼高48%);桨间距为1.5倍螺旋桨直径时涡干涉最小,拉力系数提升9.2%。结果表明:MRF模型可高精度预测滑流-气动耦合效应;滑流对前翼的气动调控呈强非线性,攻角增大导致升力增益衰减;1.5倍螺旋桨直径为抑制涡干涉的最佳安装间距。 展开更多
关键词 串列翼飞行器 螺旋桨 滑流效应 多重参考系模型 计算流体力学
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A multiple transistor combination low-voltage curvature-corrected bandgap reference 被引量:4
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作者 苏凯 龚敏 +1 位作者 秦怀斌 孙晨 《Journal of Semiconductors》 EI CAS CSCD 2013年第6期152-156,共5页
A new bandgap reference(BGR) curvature compensation technology is proposed,which is a kind of multiple transistor combination.On the basis of the existing first-order bandgap reference technology,a compensation curr... A new bandgap reference(BGR) curvature compensation technology is proposed,which is a kind of multiple transistor combination.On the basis of the existing first-order bandgap reference technology,a compensation current circuit consisting of a sink current branch and a source current branch is added.The BGR was designed and simulated by using Semiconductor Manufacturing International Corporation(SMIC) 0.18μm CMOS process.The simulation results showed that when the power supply voltage was 1 V,the temperature coefficient of the BGR was 2.08 ppm/℃with the temperature range from—40 to 125℃,the power supply rejection ratio (PSRR) was—64.77 dB and the linear regulation was 0.44 mV/V with the supply power changing from 0.85 to 1.8 V. 展开更多
关键词 bandgap reference temperature coefficient multiple transistor combination PSRR line regulation
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Radiometric Cross-Calibration for Multiple Sensors with the Moon as an Intermediate Reference 被引量:1
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作者 Lu ZHANG Peng ZHANG +4 位作者 Xiuqing HU Lin CHEN Min MIN Na XU Ronghua WU 《Journal of Meteorological Research》 SCIE CSCD 2019年第5期925-933,共9页
The instrument cross-calibration is an effective way to assess the quality of satellite data. In this study, a new method is proposed to cross-calibrate the sensors among satellite instruments by using a RObotic Lunar... The instrument cross-calibration is an effective way to assess the quality of satellite data. In this study, a new method is proposed to cross-calibrate the sensors among satellite instruments by using a RObotic Lunar Observatory(ROLO) model and Apollo sample reflectance in reflective solar bands(RSBs). The ROLO model acts as a transfer radiometer to bridge between the instruments. The reflective spectrum of the Apollo sample is used to compensate for the difference in the instrument's relative spectral responses(RSRs). In addition, the double ratio between the observed lunar irradiance and the simulated lunar irradiance is used to reduce the difference in instrument lunar viewing and illumining geometry. This approach is applied to the Moderate Resolution Imaging Spectroradiometer(MODIS), the Sea-Viewing Wide Field-of-View Sensor(Sea Wi FS), and the Advanced Land Imager(ALI) on board three satellites, respectively. The mean difference between MODIS and Sea Wi FS is less than 3.14%, and the difference between MODIS and ALI is less than 4.75%. These results indicate that the proposed cross-calibration method not only compensates for the RSR mismatches but also reduces the differences in lunar observation geometry. Thus,radiance calibration of any satellite instrument can be validated with a reference instrument bridged by the moon. 展开更多
关键词 radiometric CROSS-CALIBRATION multiple SENSORS CALIBRATION reference
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Feasibility study of phase-sensitive imaging based on multiple reference optical coherence tomography 被引量:1
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作者 Roshan Dsouza Hrebesh Subhash +4 位作者 Kai Neuhaus Paul M.McNamara Josh Hogan Carol Wilson Martin J.Leahy 《Chinese Optics Letters》 SCIE EI CAS CSCD 2017年第9期25-30,共6页
Multiple reference optical coherence tomography(MR-OCT) is a recently developed, low-cost and compact time-domain OCT solution for primary care and consumer level applications. A combination of a voice coil actuator... Multiple reference optical coherence tomography(MR-OCT) is a recently developed, low-cost and compact time-domain OCT solution for primary care and consumer level applications. A combination of a voice coil actuator and a partial mirror(PM) extends the scan range for imaging depths of approximately 1 mm in biological samples. Our previous research on MR-OCT is based only on intensity information obtained from the depth-resolved interference signal. In this Letter, we extract the phase information from the MR-OCT signal and, hence, provide an additional contrast modality. The phase sensitivity of the system is measured to be approximately 0.2 and 1.5 rad for the first and twelfth orders of reflection when using a mirror as the sample.This Letter describes first results of phase-sensitive data measured on a phantom obtained with MR-OCT. Data from a chick embryo chorioallantoic membrane(CAM) is used to demonstrate the feasibility of MR-OCT for in vivo phase-sensitive imaging. 展开更多
关键词 Feasibility study of phase-sensitive imaging based on multiple reference optical coherence tomography VCM Figure CAM
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Multiple temporal reference frames revealed by a reproduction task
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作者 Yunfei Fan Xiaoxuan Li Yan Bao 《PsyCh Journal》 2023年第6期832-834,共3页
The study investigates whether participants can establish multiple temporal references in a temporal reproduction task.The results show that participants can learn and maintain two references for the overlapping inter... The study investigates whether participants can establish multiple temporal references in a temporal reproduction task.The results show that participants can learn and maintain two references for the overlapping intervals with the short distribution being overestimated towards the long one. 展开更多
关键词 duration perception internal reference multiple temporal references temporal reproduction time perception
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星载准绝对式光电编码器抗污方法
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作者 韩庆阳 沈宏海 +2 位作者 马天翔 梁超 王志冲 《北京航空航天大学学报》 北大核心 2025年第6期2014-2021,共8页
为提高星载准绝对式光电编码器的抗油污能力,提出多参考点绝对角位移识别和多读数头数据融合方法。介绍星载准绝对式光电编码器的组成和处理电路设计;提出多参考点绝对角位移的识别方法,防止因油污造成的绝对角位移误识别,并采用多读数... 为提高星载准绝对式光电编码器的抗油污能力,提出多参考点绝对角位移识别和多读数头数据融合方法。介绍星载准绝对式光电编码器的组成和处理电路设计;提出多参考点绝对角位移的识别方法,防止因油污造成的绝对角位移误识别,并采用多读数头数据融合的方法,判断并消除错误的读数头测量数据;通过角位移曲线和角速度曲线对比实验,验证所提方法的有效性,并使用自准直平行光管和23面体检测精度。实验结果表明:所提方法能够有效的解决圆光栅被污染带引起的角位移错误问题,确保角位移正确可靠;经检验角位移误差最大值为4.6",最小值为-0.6",峰峰值为5.2",均方差为4.3"。满足星载准绝对式光电编码器抗污能力和精度要求,并已成功在工程中应用,效果良好。所提方法对提高星载准绝对式光电编码器抗油污能力,有实用价值。 展开更多
关键词 星载 准绝对式光电编码器 抗污能力 多参考点 多读书头
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基于沟槽涵道的大桨涵间隙涵道螺旋桨悬停效率改进设计 被引量:1
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作者 胡峪 张学鹏 +2 位作者 王强 罗子牛 王国强 《航空动力学报》 北大核心 2025年第3期123-134,共12页
为提高涵道螺旋桨气动效率,需要很小桨涵间隙,导致加工和使用维护成本大幅增加。为此基于沟槽涵道构型,研究大桨涵间隙时改进效率的方法。基于雷诺平均NS方程和MRF方法展开计算研究。首先基于常规无沟槽涵道构型开展分析,当间隙比从1倍... 为提高涵道螺旋桨气动效率,需要很小桨涵间隙,导致加工和使用维护成本大幅增加。为此基于沟槽涵道构型,研究大桨涵间隙时改进效率的方法。基于雷诺平均NS方程和MRF方法展开计算研究。首先基于常规无沟槽涵道构型开展分析,当间隙比从1倍基准间隙比增大到4倍时,悬停效率下降超25%,桨涵间隙增加导致效率显著下降。其次基于沟槽涵道构型开展分析,发现桨尖位置和沟槽外形是决定悬停效率的关键变量。通过向沟槽内适当延伸桨尖,可以在间隙比为6.7倍基准间隙比时,悬停效率无明显下降,若采用圆形沟槽,则间隙比为2倍基准间隙比时,悬停效率反而提高5.2%,最终通过测力试验验证,证明沟槽涵道构型可在大桨涵间隙时改进气动效率,降低加工和使用维护成本。 展开更多
关键词 涵道螺旋桨 沟槽涵道 桨涵间隙 悬停效率 多参考系模型
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双标多测法在香薷5个成分含量测定中的应用
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作者 刘丽琴 徐载萍 +5 位作者 付文艳 袁铭铭 赵雯 杨莘锴 万林春 魏峰 《药物分析杂志》 北大核心 2025年第5期821-832,共12页
目的:建立双标多测(TRSDMC)法同时测定香薷中野黄芩苷、迷迭香酸、黄芩素-7-甲醚、香荆芥酚、麝香草酚5个成分的含量,更加经济有效地对香薷进行质量控制研究。方法:采用HPLC法,在13根不同型号的C18色谱柱上测定香薷5个成分的实际保留时... 目的:建立双标多测(TRSDMC)法同时测定香薷中野黄芩苷、迷迭香酸、黄芩素-7-甲醚、香荆芥酚、麝香草酚5个成分的含量,更加经济有效地对香薷进行质量控制研究。方法:采用HPLC法,在13根不同型号的C18色谱柱上测定香薷5个成分的实际保留时间,以各成分在各色谱柱下的平均保留时间为各组分的标准保留时间。选取迷迭香酸(峰2)和香荆芥酚(峰4)作为双标化合物,使用双标线性校正(LCTRS)法进行色谱峰定位;以迷迭香酸为对照,用相对校正因子测定各成分含量,并与外标法(ESM)测定结果进行比较;采用化学计量学方法分析香薷差异性质量标志物。结果:LCTRS法对待测组分的预测结果准确且色谱柱适用范围广;野黄芩苷、黄芩素-7-甲醚、香荆芥酚和麝香草酚相对于迷迭香酸的校正因子分别为0.8533、0.4752、3.0347、2.7386,其RSD均在2.0%以内,2种方法计算的含量值无明显差异。24批香薷中野黄芩苷、迷迭香酸、黄芩素-7-甲醚、香荆草酚、麝香草酚的含量分别为0.05~2.87、0.73~9.73、0.04~0.99、0.36~8.52、0.61~10.27 mg·g^(-1)。24批香薷样品可以聚为3类,麝香草酚、香荆芥酚、黄芩素-7-甲醚为香薷的差异性质量标志物。结论:本文建立的同时测定香薷中5个成分含量的TRSDMC法稳定、可靠,可为香薷的整体质量控制提供新的思路。 展开更多
关键词 香薷 相对校正因子 双标多测法 双标线性校正法 含量测定
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基于贝叶斯优化方法的高速共轴对转螺旋桨桨叶气动外形优化设计 被引量:1
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作者 赵荣泽 王博 +2 位作者 曹德松 胡东根 招启军 《空气动力学学报》 北大核心 2025年第3期67-77,I0002,共12页
共轴对转螺旋桨因其两桨间距小、相互间气动干扰显著,在气动和噪声方面存在着不容忽视的问题。本文构建了基于贝叶斯优化方法的高速共轴对转螺旋桨桨叶气动外形优化框架,以提升巡航状态气动效率为目标开展优化设计。优化框架中,为更准... 共轴对转螺旋桨因其两桨间距小、相互间气动干扰显著,在气动和噪声方面存在着不容忽视的问题。本文构建了基于贝叶斯优化方法的高速共轴对转螺旋桨桨叶气动外形优化框架,以提升巡航状态气动效率为目标开展优化设计。优化框架中,为更准确地评估两桨间气动干扰、高速条件下空气压缩性和复杂桨叶外形对高速共轴对转螺旋桨气动特性的影响,采用基于RANS方程的多重参考坐标系方法评估其气动性能;构建Kriging代理模型以描述样本点输入与响应之间的关系,并使用组合加点准则提高寻优效率;结合气动和结构特性,分别对前、后桨的弦长、扭转和前/后掠分布进行参数化。在考虑整流罩和旋转轴影响的情况下,得出的优化方案综合气动效率达到0.8413,相较于初步方案提升约1.53%;优化方案的前、后桨载荷分别约在0.75R和0.7R处达到峰值。本文最终得到的优化设计方案,揭示了高效率的高速共轴对转螺旋桨桨叶的外形特征。 展开更多
关键词 共轴对转螺旋桨 气动优化设计 代理优化 加点准则 多重参考坐标系
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基于计算流体动力学的锻件淬火方式优化
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作者 周海鹏 王晓芳 +5 位作者 雷雪 仝大明 王婧 韩利战 骆晓萌 顾剑锋 《金属热处理》 北大核心 2025年第11期161-167,共7页
以SA508-3钢制核电蒸发器上封头锻件为研究对象,针对上封头的产品特点,对其淬火方案进行了优化。通过描述旋转运动的多重参考系(Multiple reference frame,MRF)模型,得出淬火槽中冷却介质的流动状态。结果表明,在淬火槽内增设圆锥台型... 以SA508-3钢制核电蒸发器上封头锻件为研究对象,针对上封头的产品特点,对其淬火方案进行了优化。通过描述旋转运动的多重参考系(Multiple reference frame,MRF)模型,得出淬火槽中冷却介质的流动状态。结果表明,在淬火槽内增设圆锥台型导流罩并配置内腔抽水泵后,上封头内外表面水流速度基本均超过0.3 m/s,内腔平均流速提升至约0.6 m/s,流动死区显著消除。淬火后外壁平均硬度达到34.75 HRC,且其内外壁硬度极差和标准偏差均小于其他方案,表明该方案处理上封头在硬度水平和均匀性方面均最优,整体性能表现最佳。 展开更多
关键词 SA508-3钢 锻件 淬火方式 计算流体动力学 多重参考系模型
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面向时变目标协同跟踪的多自主无人船分层有限时间优化调控 被引量:1
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作者 葛明峰 李一凡 +2 位作者 刘智伟 谷志威 陈谦 《控制与决策》 北大核心 2025年第1期279-284,共6页
针对多自主无人船(ASVs)系统的时变多目标协同跟踪问题,提出一种新型分层有限时间优化调控算法.首先,设计一个反映多ASVs系统在跟踪过程中能量消耗的目标函数;然后,开发一个有限时间优化估计器(FTOE),以在ASV形成特定编队的同时遵循期... 针对多自主无人船(ASVs)系统的时变多目标协同跟踪问题,提出一种新型分层有限时间优化调控算法.首先,设计一个反映多ASVs系统在跟踪过程中能量消耗的目标函数;然后,开发一个有限时间优化估计器(FTOE),以在ASV形成特定编队的同时遵循期望轨迹的情况下最小化目标函数,目标轨迹是可变的,不恒定的;接着,在有限时间本地控制器(FTLC)中,通过跟踪FTOE,多ASVs系统的航行状态可在有限时间内以最小化目标函数的方式稳定在多个预定的各种时变轨迹附近;最后,给出有限时间稳定性的证明,并计算沉降时间.仿真结果验证了所提出分层算法的有效性. 展开更多
关键词 时变参考信号的优化 多目标编队跟踪 多自主无人船(ASVs)系统 有限时间优化控制
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北斗区域基准站网多参考一致性检验分析
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作者 李庚辰 徐彦田 +4 位作者 罗力 韩忠倫 于亚杰 曲麒霖 王春杨 《测绘科学》 北大核心 2025年第6期36-44,共9页
针对如何提升北斗卫星导航定位基准站网实时差分增强定位的安全可信性的问题,该文提出了一种多基准站参考一致性监测算法,将4个基准站伪距改正量均值和某一基准站未参与计算的伪距改正量均值间做差求取伪距B值,并对该值进行检验。同时... 针对如何提升北斗卫星导航定位基准站网实时差分增强定位的安全可信性的问题,该文提出了一种多基准站参考一致性监测算法,将4个基准站伪距改正量均值和某一基准站未参与计算的伪距改正量均值间做差求取伪距B值,并对该值进行检验。同时对接收机钟差进行3倍中误差离散度进行校验以消除卫星引起的相同误差项,按照一定逻辑判断基准站网伪距改正量故障事件。仿真和实测结果表明,该算法能够有效监测北斗地球静止轨道(GEO)、倾斜地球同步轨道(IGSO)和中地球轨道(MEO)卫星或基准站伪距异常大于1 m的故障事件,为低空飞行等提供定位保障。 展开更多
关键词 基准站网 多参考一致性监测 北斗卫星导航定位 伪距修正量 B值
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