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3D Multiphase Piecewise Constant Level Set Method Based on Graph Cut Minimization 被引量:2
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作者 Tiril P Gurholt Xuecheng Tai 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第4期403-420,共18页
Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmenta... Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches. 展开更多
关键词 Piecewise constant level set method energy minimization graph cut SEGMENTATION three-dimensional.
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An Improved Mumford-Shah Model and Its Applications to Image Processing with the Piecewise Constant Level Set Method 被引量:1
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作者 SONG Jin-Ping LI Shuai-Jie 《自动化学报》 EI CSCD 北大核心 2007年第12期1259-1262,共4页
为快分割并且降噪,提高 penalization 学期的古典 Mumford-Shah (MS ) 模型需要,即增加 penalization 参数,它导致目标的渐渐的消失。在这份报纸,我们建议一个改进 Mumford-Shah (IMS ) 模型避免现象,并且采用 piecewise 常数水平... 为快分割并且降噪,提高 penalization 学期的古典 Mumford-Shah (MS ) 模型需要,即增加 penalization 参数,它导致目标的渐渐的消失。在这份报纸,我们建议一个改进 Mumford-Shah (IMS ) 模型避免现象,并且采用 piecewise 常数水平集合方法(PCLSM ) 和坡度降下方法解决最小化问题。数字实验被给显示出新模型和算法的效率和优点。 展开更多
关键词 分段持续水平集方法 分割 降噪 经典MS模型 最小化 算法
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Application of Neural network PID Controller in Constant Temper-ature and Constant Liquid-level System 被引量:11
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作者 (College of information and control engineering, University of Petroleum, Dongying 257061, China) Chen Guochu Hao Ninmei Liu Xianguang(College of electricity engineering, University of Xi ’ an Communication, Xi’ an 710049, China) Zhang Lin (Workshop of Instrument of Plastic Plant, Qilu Petrochemical Corp., Zibo 255411, China) Wang Junhong 《微计算机信息》 2003年第1期23-24,42,共3页
Guided by the principle of neural network, an intelligent PID controller based on neural network is devised and applied to control of constant temperature and constant liquidlevel system. The experiment results show t... Guided by the principle of neural network, an intelligent PID controller based on neural network is devised and applied to control of constant temperature and constant liquidlevel system. The experiment results show that this controller has high accuracy and strong robustness and good characters. 展开更多
关键词 PID控制器 神经网络 PID控制 恒温恒液位系统
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Investigations on spectroscopic parameters, vibrational levels, classical turning points and inertial rotation and centrifugal distortion constants for the 1 + X^1∑g^+ state of sodium dimer 被引量:4
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作者 余本海 戴启润 +1 位作者 施德恒 刘玉芳 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第10期2962-2967,共6页
The density functional theory (B3LYP, B3P86) and the quadratic configuration-interaction method including single and double substitutions (QCISD(T), QCISD) presented in Gaussian03 program package are employed to... The density functional theory (B3LYP, B3P86) and the quadratic configuration-interaction method including single and double substitutions (QCISD(T), QCISD) presented in Gaussian03 program package are employed to calculate the equilibrium internuclear distance Re, the dissociation energy De and the harmonic frequency We for the XIEg+ state of sodium dimer in a number of basis sets. The conclusion is gained that the best Re, De and We results can be attained at the QCISD/6-311G(3df,3pd) level of theory. The potential energy curve at this level of theory for this state is obtained over a wide internuclear separation range from 0.16 to 2.0 nm and is fitted to the analytic Murrell-Sorbie function. The spectroscopic parameters De, DO, Re, ωe, ωe Xe, αe and Be are calculated to be 0.7219 eV, 0.7135 eV, 0.31813 nm, 151.63 cm^-1, 0.7288 cm^-1, 0.000729 cm^-1 and 0.1449 cm^-1, respectively, which are in good agreement with the measurements. With the potential obtained at the QCISD/6-311G(3df,3pd) level of theory, a total of 63 vibrational states is found when J = 0 by solving the radial SchrSdinger equation of nuclear motion. The vibrational level, corresponding classical turning point and inertial rotation constant are computed for each vibrational state. The centrifugal distortion constants (Dr Hv, Lv, Mv, Nv and Ov) are reported for the first time for the first 31 vibrational states when J = 0. 展开更多
关键词 dissociation energy vibrational level turning point centrifugal distortion constant
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RESERVOIR DESCRIPTION BY USING A PIECEWISE CONSTANT LEVEL SET METHOD 被引量:3
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作者 Hongwei Li Center for Integrated Petroleum Research,University of Bergen,Norway Department of Mathematics,Capital Normal University,Beijing 100037,China Xuecheng Tai Department of Mathematics,University of Bergen,Norway +1 位作者 Division of Mathematical Sciences,School of Physical and Mathematical Sciences,Nanyang Technological University,Singapore Sigurd Ivar Aanonsen Center for Integrated Petroleum Research,University of Bergen,Norway Department of Mathematics,University of Bergen,Norway 《Journal of Computational Mathematics》 SCIE CSCD 2008年第3期365-377,共13页
We consider the permeability estimation problem in two-phase porous media flow. We try to identify the permeability field by utilizing both the production data from wells as well as inverted seismic data. The permeabi... We consider the permeability estimation problem in two-phase porous media flow. We try to identify the permeability field by utilizing both the production data from wells as well as inverted seismic data. The permeability field is assumed to be piecewise constant, or can be approximated well by a piecewise constant function. A variant of the level set method, called Piecewise Constant Level Set Method is used to represent the interfaces between the regions with different permeability levels. The inverse problem is solved by minimizing a functional, and TV norm regularization is used to deal with the ill-posedness. We also use the operator-splitting technique to decompose the constraint term from the fidelity term. This gives us more flexibility to deal with the constraint and helps to stabilize the algorithm. 展开更多
关键词 Inverse problem level set method Piecewise constant Operator splitting Reservoir description
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Quantization Heat Capacity Equations at Constant Volume According to Energy Levels and Planck Constant
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作者 Daekyoum Kim Youngpak Lee 《American Journal of Analytical Chemistry》 2018年第8期353-365,共13页
The quantization thermal excitation isotherms based on the maximum triad spin number (G) of each energy level for metal cluster were derived as a function of temperature by expanding the binomial theorems according to... The quantization thermal excitation isotherms based on the maximum triad spin number (G) of each energy level for metal cluster were derived as a function of temperature by expanding the binomial theorems according to energy levels. From them the quantized geometric mean heat capacity equations are expressed in sequence. Among them the five quantized geometric heat capacity equations, fit the best to the experimental heat capacity data of metal atoms at constant pressure. In the derivations we assume that the triad spin composed of an electron, its proton and its neutron in a metal cluster become a basic unit of thermal excitation. Boltzmann constant (kB) is found to be an average specific heat of an energy level in a metal cluster. And then the constant (kK) is found to be an average specific heat of a photon in a metal cluster. The core triad spin made of free neutrons may exist as the second one additional energy level. The energy levels are grouped according to the forms of four spins throughout two axes. Planck constant is theoretically obtained with the ratio of the internal energy of metal (U) to total isotherm number (N) through Equipartition theorem. 展开更多
关键词 Statistical Thermodynamics QUANTIZED Heat Capacity of Metal Five Energy levels BINOMIAL Theorem BOLTZMANN constantS PLANCK constant
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A Production Inventory Model of Constant Production Rate and Demand of Level Dependent Linear Trend
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作者 Shirajul Islam Ukil Md. Sharif Uddin 《American Journal of Operations Research》 2016年第1期61-70,共10页
The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constan... The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle. 展开更多
关键词 Production Inventory level Dependent Linear Trend constant Production Rate
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流域水资源调配关键技术研究
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作者 巴音达拉 魏光辉 +2 位作者 陈红川 宋莹 谢镇泽 《电脑与电信》 2024年第4期10-13,共4页
长距离调水工程往往具有规模大、管理难、条件差和系民生等特点,根据中央提出的关于加快构建“系统完备、安全可靠,集约高效、绿色智能,循环通畅、调控有序”的国家水网的要求,以提升流域水资源调配能力为目的,通过建设自动化和信息化软... 长距离调水工程往往具有规模大、管理难、条件差和系民生等特点,根据中央提出的关于加快构建“系统完备、安全可靠,集约高效、绿色智能,循环通畅、调控有序”的国家水网的要求,以提升流域水资源调配能力为目的,通过建设自动化和信息化软件,推行扁平化改革,压缩管理层级,形成高效的水资源调配管理新模式。通过对某流域调水工程信息化系统的建设,开发水资源管控、流量平衡和恒水位控制系统,能够满足水资源调配业务的需求。 展开更多
关键词 调水工程 水资源管控 水量平衡 恒水位控制
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PLC自控系统在北河口水厂二期工程中的应用
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作者 曾敏 《电工技术》 2024年第2期6-8,共3页
结合北河口水厂二期工程实例,介绍了PLC自动控制系统在自来水厂中的应用情况,对自来水厂的建设有着重要参考价值。
关键词 PLC 自来水厂 光纤环网 自动控制 恒水位/恒压运行
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LCL型三电平并网逆变器定频滞环控制研究
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作者 谢宝平 曾江 +1 位作者 陈伟国 叶康权 《电力电子技术》 2024年第3期1-5,共5页
为增强并网逆变器控制性能,降低入网电流谐波含量,提出一种基于LCL型三电平逆变器的定频滞环控制。推导桥侧电流与网侧电流关系,通过对桥侧电流的直接控制进而间接控制网侧电流。将参考电压六边形区域分为12个小平行四边形区域,实现对... 为增强并网逆变器控制性能,降低入网电流谐波含量,提出一种基于LCL型三电平逆变器的定频滞环控制。推导桥侧电流与网侧电流关系,通过对桥侧电流的直接控制进而间接控制网侧电流。将参考电压六边形区域分为12个小平行四边形区域,实现对相间误差电流的解耦控制。根据上一周期的开关时间和环宽,实时调整下一周期环宽以实现定频控制。此外,借助扩张状态观测器进行微分跟踪,完成参考电压矢量扇区判断和桥侧参考电流估计。最后通过仿真和半实物仿真对定频滞环控制策略进行验证。 展开更多
关键词 三电平逆变器 定频滞环控制 半实物仿真
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基于近似计算技术的多级逻辑电路面积优化
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作者 赵维凯 王伦耀 +2 位作者 岑旭梦 夏银水 储著飞 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第9期2893-2901,共9页
针对现有多级逻辑近似优化算法在大型电路优化时无法较好兼顾优化效果与算法速度的问题,提出一种基于常量替换的多级逻辑电路面积优化算法。该算法通过在与非图(AIG)中引入节点输出距离、常量传输距离等参数,并结合提出的多扇出节点常... 针对现有多级逻辑近似优化算法在大型电路优化时无法较好兼顾优化效果与算法速度的问题,提出一种基于常量替换的多级逻辑电路面积优化算法。该算法通过在与非图(AIG)中引入节点输出距离、常量传输距离等参数,并结合提出的多扇出节点常量替换过程中错误率控制方法,在全局范围内提取合适替换的候选节点集和每个候选节点输出的常量替换值;同时,通过根据电路规模选取不同的错误率计算方法等策略,实现了错误率约束下的多级逻辑电路面积近似优化并使算法速度得到提高。所提算法用C语言和ABC内置命令编程实现,使用EPFL及MCNC电路进行测试。实验结果表明:所提算法与已提出的常量替换方法相比,面积优化效果提升48.77%;相较于近似关心集重代换的近似逻辑综合(ALSRAC)优化算法,所提算法在面积优化和运算时间上分别有1.28%和60.91%的提升。 展开更多
关键词 多级电路 近似计算 误差约束 常量替换 逻辑优化
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基于韦布尔分布下改进型恒虚警检测器的检测性能分析
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作者 梁懿 张双根 《天津理工大学学报》 2024年第2期54-62,共9页
为了提高恒虚警检测器(constant false alarm rate detector,CFAR)在有干扰目标存在的杂波环境下的检测性能,提出了5种基于自适应删除(automatic censored mean level detector,ACMLD)恒虚警算法与均值类算法的改进型,并在韦布尔分布模... 为了提高恒虚警检测器(constant false alarm rate detector,CFAR)在有干扰目标存在的杂波环境下的检测性能,提出了5种基于自适应删除(automatic censored mean level detector,ACMLD)恒虚警算法与均值类算法的改进型,并在韦布尔分布模型下对影响背景杂波功率估计的参考单元长度和干扰目标个数进行检测概率分析。结果表明:基于该改进型检测器可有效提高有干扰目标的检测性能,其中改进型单侧自适应删除(single automatic censored mean level detector,SACMLD)算法适合在一侧参考窗均匀的情况下使用,而自适应删除最小(adaptive censored smallest of detector,ACSO)算法适合两侧参考窗都不均匀的情况下使用。文中提出的基于韦布尔分布下改进型恒虚警检测器可为铁路、航空等多目标环境检测提供参考。 展开更多
关键词 韦布尔分布 检测 自适应删除 多目标 恒虚警
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基于Lebesgue常数最小保水平渐近线的重心有理插值
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作者 赵前进 杨帆 《合肥学院学报(综合版)》 2024年第2期28-31,36,共5页
提出了一种保水平渐近线的重心有理插值方法。首先研究重心有理插值保水平渐近线的条件,进一步以Lebesgue常数最小为目标函数,同时以重心有理插值函数没有极点、没有不可达点、插值函数保水平渐近线以及重心权的规范化等为约束条件,建... 提出了一种保水平渐近线的重心有理插值方法。首先研究重心有理插值保水平渐近线的条件,进一步以Lebesgue常数最小为目标函数,同时以重心有理插值函数没有极点、没有不可达点、插值函数保水平渐近线以及重心权的规范化等为约束条件,建立优化模型解得最优权,从而得到保水平渐近线的重心有理插值。通过数值例子证明了算法有效性。 展开更多
关键词 LEBESGUE常数 重心有理插值 插值权 保水平渐近线
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并网光伏系统中3L-T-type QZSI参与电网电压不平衡控制
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作者 王强 李上杨 张津 《科学技术与工程》 北大核心 2024年第11期4510-4519,共10页
针对传统逆变器在不平衡网压情况下工作时较难抑制输入电网有功功率振荡分量的问题,提出一种基于三电平T型准阻抗源逆变器(three level T-type quasi-Z source inverter,3L-T-type QZSI)抑制有功功率振荡分量的控制策略。从功率理论推... 针对传统逆变器在不平衡网压情况下工作时较难抑制输入电网有功功率振荡分量的问题,提出一种基于三电平T型准阻抗源逆变器(three level T-type quasi-Z source inverter,3L-T-type QZSI)抑制有功功率振荡分量的控制策略。从功率理论推导得到其并网的参考电流,实现并网有功功率恒定且以单位功率因数为目标的控制策略。即:使用二阶广义积分器(second-order generalized integrator,SOGI)完成电压的正负序分离;再结合基于载波的电平位移脉宽调制(level-shift pulse width modulation,LS-PWM)技术,用以调节功率开关直通状态的占空比和叠加的平衡分量,实现直流侧电压控制和中点电压平衡。最后,在Simulink平台上模拟了电网电压不平衡情况,对间歇性能源不同出力情况进行了仿真,仿真结果表明,该策略可有效抑制间歇性能源的有功功率二倍频波动,有利于实现中点电位平衡和间歇性能源并网稳定运行。 展开更多
关键词 三电平逆变器 电网电压不平衡 恒定有功功率 直通占空比 中点电位平衡
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Theoretical investigations of spectroscopic parameters and molecular constants for electronic ground state of Cl_2 and its isotopes
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作者 施德恒 张小妞 +2 位作者 刘慧 朱遵略 孙金锋 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期236-244,共9页
The potential energy curve of the C12 (X1∑g+) is investigated by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the largest correla... The potential energy curve of the C12 (X1∑g+) is investigated by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the largest correlation-consistent basis set, aug-cc-pV6Z, in the valence range. The theoretical spectroscopic parameters and the molecular constants of three isotopes, 35Cl2, 35Cl37Cl and 37Cl2, are studied. For the 35Cl2(X1∑g+), the values of Do, De, Re, We, we)we, ae and Be are obtained to be 2.3921 eV, 2.4264 eV, 0.19939 nm, 555.13 cm-1, 2.6772 cm-1, 0.001481 cm-1 and 0.24225 cm-1, respectively. For the 356137Cl(X1∑g+), the values of Do, De, Re, We, WeXe, ae and Be are calculated to be 2.3918 eV, 2.4257 eV, 0.19939 nm, 547.68 cm-1, 2.6234 cm-1, 0.00140 cm^1 and 0.23572 cm-1, respectively. And for the 37Cl2(X1∑g+), the values of Do, De, Re, We, WeXe, ae and Be are obtained to be 2.3923 eV, 2.4257 eV, 0.19939 nm, 540.06 cm-1, 2.5556 cm-1, 0.00139 cm-1 and 0.22919 cm-1, respectively. These spectroscopic results are in good agreement with the available experimental data. With the potential of Cl2 molecule determined at the MRCI/aug-cc-pV6Z level of theory, the total of 59 vibrational states is predicted for each isotope when the rotational quantum number J equals zero (J = 0). The theoretical vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0, which are in excellent accordance with the available experimental findings. 展开更多
关键词 isotope effect spectroscopic parameter molecular constant vibrational level
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Empirical Approach for Planning and Designing Constant Stress Accelerated Life Tests
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作者 蒋仁言 龙旭 《Journal of Donghua University(English Edition)》 EI CAS 2015年第6期1025-1028,共4页
Accelerated life testing(ALT)has been widely used to obtain information about the product's life characteristics at normal conditions in a relatively short period of time.Two key issues with ALT are test design an... Accelerated life testing(ALT)has been widely used to obtain information about the product's life characteristics at normal conditions in a relatively short period of time.Two key issues with ALT are test design and data analysis.The test design of constant stress ALT was studied in this paper.The test design usually combines engineering experiences with optimization models.Such approaches are hard to be implemented by practitioners.A"pure"empirical approach was presented to address this issue.With the proposed approach,some of the decision variables are determined based on the results from the literature,some of the other variables are determined based on engineering analysis and /or judgment,and the remaining variables are determined based on the empirical relations developed in this paper.A real-world example is included to illustrate the appropriateness of the proposed approach. 展开更多
关键词 accelerated life testing(ALT)design constant stress stress levels test units allocation censoring type
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Study on spectroscopic parameters and molecular constants of HCl(X^1Σ^+) molecule by using multireference configuration interaction approach
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作者 张小妞 施德恒 +2 位作者 张金平 朱遵略 孙金锋 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第5期224-232,共9页
Equilibrium internuclear separations, harmonic frequencies and potential energy curves (PECs) of HCI(X1∑+) molecule are investigated by using the highly accurate valence internally contracted multireference conf... Equilibrium internuclear separations, harmonic frequencies and potential energy curves (PECs) of HCI(X1∑+) molecule are investigated by using the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with a series of correlation-consistent basis sets in the valence range. The PECs are all fitted to the Murrell-Sorbie function, and they are used to accurately derive the spectroscopic parameters (De, Do, ωeXe, αe and Be) Compared with the available measurements, the PEC obtained at the basis set, aug-cc-pV5Z, is selected to investigate the vibrational manifolds. The constants Do, De, Re, We, ωeXe, Ore and Be at this basis set are 4.4006 eV, 4.5845 eV, 0.12757 rim, 2993.33 cm^-1, 52.6273 cm^-1, 0.2981 cm^-1 and 10.5841 cm^-1, respectively, which almost perfectly conform to the available experimental results. With the potential determined at the MRCI/aug-cc-pV5Z level of theory, by numerically solving the radial Schrodinger equation of nuclear motion in the adiabatic approximation, a total of 21 vibrational levels are predicted. Complete vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are reproduced, which are in excellent agreement with the available Rydberg-Klein-Rees data. Most of these theoretical vibrational manifolds are reported for the first time to the best of our knowledge. 展开更多
关键词 dissociation energy spectroscopic parameter vibrational level inertial rotation constant
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Selection and Justification of a New Initial Level of the Material World 被引量:2
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作者 Valentyn Nastasenko 《Journal of Applied Mathematics and Physics》 2021年第5期1089-1099,共11页
The work refers to the foundations of the material world, in particular—to the field of quantum physics associated with the initial level—his fundamental physical constants and elementary particles. The study of the... The work refers to the foundations of the material world, in particular—to the field of quantum physics associated with the initial level—his fundamental physical constants and elementary particles. The study of the initial levels of structuring of this formation is necessary for a better understanding of the foundations of the structure Universe. Therefore, the solution of these problems is an urgent and important task, to which the works of many scientists of the world are devoted, from ancient times to the present. However, these tasks have not yet been fully resolved. Their solution is the main goal and scientific novelty of the work performed. For this, <strong>research methods</strong> were used based on the general principles of deduction and movement from simple initial systems to more complex ones, which are substantiated by reliable physical laws. <strong>The research results</strong> are the choice and substantiation of the initial (zero) level of the material world and a system of fundamental physical constants and physical quantities found on their basis, which precede the 1st level—elementary particles. The problems of determining the wave parameters of the gravitational field and the unified of gravitational and electromagnetic fields of the Universe were solved only as a result of the transition to the zero level of the material world. 展开更多
关键词 levels of Structuring of the Material World Fundamental Physics constants and Elementary Particles
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仿生轮腿式爬梯底盘结构设计分析与应用
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作者 冯长龙 行志刚 +1 位作者 程军 李树平 《自动化与仪表》 2023年第7期105-109,共5页
针对现有的以履带组合式、升降伸缩式、行星轮式、连杆式为底盘的爬梯装置在克服台阶等障碍物时统一存在的水平不稳定、动力消耗大和操作较难等问题,该文设计了一款可实现自调节底盘保持恒水平稳定的仿生轮腿式爬梯底盘结构。提出了以... 针对现有的以履带组合式、升降伸缩式、行星轮式、连杆式为底盘的爬梯装置在克服台阶等障碍物时统一存在的水平不稳定、动力消耗大和操作较难等问题,该文设计了一款可实现自调节底盘保持恒水平稳定的仿生轮腿式爬梯底盘结构。提出了以该结构为应用点的辅助老人上、下楼装置,完成了其机械结构方案设计、控制逻辑方案设计和核心零部件的运动学仿真分析及强度校核。基于FTdesigner技术搭建出物理样机模型并开展原理性、功能性和稳定性测试研究,试验与仿真数据表明,该装置完全自适应调节座椅水平度,具有功耗低、便捷度高、稳定性强等特点。 展开更多
关键词 仿生轮腿式 攀越楼梯 底盘结构 恒水平 辅助老人
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求最小特征频率问题的分片常数水平集方法
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作者 高祥静 张郑芳 董燕强 《杭州电子科技大学学报(自然科学版)》 2023年第2期96-102,共7页
通过引入虚拟材料,将线性弹性系统扩展到一个固定的背景域,研究结构振动最小特征频率的最大化问题。用分片常数水平集(Piecewise Constant Level Set, PCLS)方法表示不同材料区域,运用灵敏度分析得到PCLS函数最小特征频率的导数。提出... 通过引入虚拟材料,将线性弹性系统扩展到一个固定的背景域,研究结构振动最小特征频率的最大化问题。用分片常数水平集(Piecewise Constant Level Set, PCLS)方法表示不同材料区域,运用灵敏度分析得到PCLS函数最小特征频率的导数。提出一种重新启动的共轭梯度惩罚算法对二维及三维悬臂梁进行数值实验,实验结果表明,PCLS方法可以在迭代过程中自动成核和消除空洞,验证了共轭梯度惩罚算法的有效性。 展开更多
关键词 特征频率 分片常数水平集方法 灵敏度分析 共轭梯度惩罚算法
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