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High-order approximate solution of nonlinear acoustic equation:development and validation

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Chinese Journal of Acoustics 2021年第3期40卷 389-400页

作者： zhang Shigong zhang kesheng WU Xianmei Guizhou Institute of Technology Guiyang550003 Guizhou Research Center for Multidisciplinary Conjunction of Medicine and Engineering Guiyang550003 Institute of Acoustics Chinese Academy of SciencesBeijing100190

For the nonlinear acoustic wave equation,the commonly used second harmonic solution is not accurate enough,which causes a big error in measuring the material nonlinearity.Using perturbation inetliud,nonlinear acoustic wave equation can be expanded into a series of inhomogeneous partial differential equations.The special solution forms of high harmonics are formulated according to the properties of low harmonic solutions.Then the high-order harmonic solutions are obtained with symbol calculation tool.Thus the high-order approximate solution of the second harmonic can be achieved by summing up all of the second harmonic solutions.To verify the high-order approximate solution,nonlinear acoustic experiments are carried out in water.The results show that the relative amplitude of second harmonic increases firstly and then decreases with the propagation distance and the excited primary amplitude.The high-order approximate solution can compensate for the theory deficiency of the second harmonic perturbation solution,can broaden experimental range in measuring the material nonlinearity,and can improve the accuracy of the measured nonlinearity by making full use of the experimental data.

关键词： approximate harmonic equation

Gas equilibrium heat capacity synthesis under the influence of acoustic relaxation process and its application in gas detection

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Chinese Journal of Acoustics 2019年第4期38卷 386-402页

作者： zhang kesheng zhang Xiangqun SHAO Fang School of Electrical and Information Engineering Guizhou Institute of TechnologyGuiyang 550003 School of Electronic Information and Communications Huazhong University of Science and TechnologyWuhan 430074 School of Mechanical Engineering Guizhou Institute of TechnologyGuiyang 550003

In an excitable gas,the molecular vibration relaxation process caused by an acoustic disturbance leads the equilibrium heat capacity to the effective one that depends on the acoustic frequency,resulting in acoustic dispersion and acoustic relaxational absorption.Based on the algorithm of synthesizing a single-relaxation process,we develop a synthesizing method to get the equilibrium heat capacities of excitable gases from the two-frequency acoustic speed and absorption measurements.The two measurement frequencies are selected in the range where the acoustic relaxational absorption is obvious.The method can obtain the heat capacities of internal and external degrees of freedom of gas molecules respectively,and effectively eliminate the influence of the acoustic relaxation process on the measurement results of excitable gas heat capacity.For various gases,consisting of CO2,CH4,Cl2,N2 and O2 at room temperature,the gas heat capacities obtained in this paper agree with the thermodynamic theoretical calculations based on the Planck-Einstein formula,and the maximum relative error is 3.51% in comparison to the experimental result.The synthesized heat capacities of rotation and vibration can be applied to the detection of gas molecular geometry,vibration frequency and mole fractions of gas mixtures.

关键词： relaxation equilibrium gases

Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

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Chinese Journal of Acoustics 2018年第2期37卷 202-218页

作者： zhang kesheng zhang Xiangqun TANG Wenyong XIAO Yingqun JIANG Xueqin School of Electrical and Information Engineering~ Guizhou Institute of Technology Guiyang 550003 School of Electronic Information and Communications Huazhong University of Science and Technology Wuhan 430074 School of Big Data Guizhou Institute of Technology Guiyang 550003

To research the correlation between vibrational energy transition rates and acoustic relaxation processes in excitable gases, the vibrational relaxation theory provided by Tanczos [J. Chem. Phy3. 25, 439 （1956）] is applied to calculate the energy transition rates of Vibrational- Vibrational （V-V） and Vibrational-Translational （V-T） energy transfer in gas mixtures. The results of calculation for the multi-relaxation processes in various gas mixtures, consisting of carbon dioxide, methane, chlorine, nitrogen, and oxygen at room temperature, demonstrate that the acoustic energy stagnated in every vibrational mode is coupled with each other through V-V energy exchanges. The vibrational excitation energy will relax through the V-T de-excitation path of the lowest mode because of its fastest V-T transition rate, resulting in that only one absorption peak can be measured for most of excitable gas mixtures. Thus, an effective model is provided to analyze how the vibrational energy transition rates affect the characteristics of acoustic relaxation processes and acoustic propagation in excitable gas mixtures.

关键词： Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

基于深度学习的智能除草视觉导航方法研究及实现

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农机使用与维修 2024年第5期 36-38页

作者：王云德刘孜文张克盛甘肃畜牧工程职业技术学院甘肃武威733006

该文基于深度学习提出了一种智能除草视觉导航方法,通过搭建硬件系统,用于采集农田信息和导航控制。该模型通过对实时图像数据进行处理和分析,能够准确地识别出杂草并实现导航控制,从而实现智能除草的目标。试验结果表明,该文提出的方... 详细信息

该文基于深度学习提出了一种智能除草视觉导航方法,通过搭建硬件系统,用于采集农田信息和导航控制。该模型通过对实时图像数据进行处理和分析,能够准确地识别出杂草并实现导航控制,从而实现智能除草的目标。试验结果表明,该文提出的方法在不同场景下都具有较高的识别准确率和导航精度,具有良好的实用性和推广价值。

关键词：智能除草技术农业智能化深度学习视觉导航杂草识别农田信息采集

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基于Mask R-CNN的电力关键设备运行状态检测

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电子设计工程 2024年第2期32卷 107-110,115页

作者：吕超杨德宇刘文杰张克胜内蒙古电力科学研究院内蒙古呼和浩特011200

为判断电力关键设备两端负载电压与干路总电压之间的数值关系,提出基于Mask R-CNN的电力关键设备运行状态检测方法。在Mask R-CNN网络结构中,判断电量信号的时域范围与频域范围。然后根据负荷阻抗特征计算交流参数的取值结果,再联合已... 详细信息

为判断电力关键设备两端负载电压与干路总电压之间的数值关系,提出基于Mask R-CNN的电力关键设备运行状态检测方法。在Mask R-CNN网络结构中,判断电量信号的时域范围与频域范围。然后根据负荷阻抗特征计算交流参数的取值结果,再联合已获取的电信号参量,求解连续相关函数,从而检测电力关键设备运行状态。实验过程中,设备两端负载电压、内阻消耗电压之和与干路总电压之间的差值未超过1.5 V,说明该方法能够证明电力关键设备两端负载电压、内阻消耗电压之和等于干路总电压数值的猜想成立,可以根据该验证检测电力关键设备运行状态是否正常。

关键词： Mask R-CNN模型电力设备运行状态负荷阻抗交流参数负载电压

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1α-羟基胆固醇的合成工艺改进

中国医药工业杂志 2023年第8期54卷 1198-1201页

作者：张克盛葛欢恬孙彬金灿浙江工业大学药学院浙江杭州310014 国家化学原料药合成工程技术研究中心浙江杭州310014

文章对1α-羟基维生素D3关键中间体1α-羟基胆固醇(1)的合成工艺进行改进:以胆固醇(2)为原料,经过氧化脱氢、环氧化、选择性开环、异构化和还原等5步反应得到1。较现有1的制备工艺,该路线一方面规避了液氨/锂于-78℃还原的苛刻条件,操... 详细信息

文章对1α-羟基维生素D3关键中间体1α-羟基胆固醇(1)的合成工艺进行改进:以胆固醇(2)为原料,经过氧化脱氢、环氧化、选择性开环、异构化和还原等5步反应得到1。较现有1的制备工艺,该路线一方面规避了液氨/锂于-78℃还原的苛刻条件,操作简单,条件温和;另一方面采用苯硒酚对1α,2α-环氧-4,6-胆甾二烯-3-酮(4)进行选择性开环,并由I2/乙酸异丙烯酯体系实现由烯酮异构化为烯醇酯。采用优化后的工艺,1的总收率达40%,纯度为98%。

关键词： 1α-羟基胆固醇 1α-羟基维生素D_(3) 中间体合成

Positioning and function of secondary general hospital in community rehabilitation of disabled persons-a case study of a secondary general hospital in Changsha city

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Journal of Translational Neuroscience 2021年第3期6卷 12-18页

作者： Jin Song Zhichun Zhu kesheng zhang Rehabilitation Center Hunan Provincial Rehabilitation HospitalChangsha 410021China Geriatric Rehabilitation Unit Hunan Provincial Rehabilitation HospitalChangsha 410021China

Objective:the positioning of secondary hospitals in the community rehabilitation work system and the status of community medical rehabilitation ser-vices for the disabled in Changsha were clarified through investigation and study of the 2019 income of a second-ary general hospital in Changsha.Suggestions from var-ious parties were integrated to provide feasible ideas for expanding the role of secondary hospitals in community rehabilitation.Methods:the 2019 income of a secondary general hospital in Changsha was statistically analyzed,a community rehabilitation questionnaire was designed,and a field survey was carried out focusing on 19 issues including rehabilitation service items,rehabilitation facil-ities and equipment,and the satisfaction of rehabilitation practitioners.Results:in the total hospitalization expenses of a secondary general hospital in Changsha city in 2019,rehabilitation physiotherapy expenses accounted for 7%,and drug treatment expenses accounted for 25%.In addi-tion,in the survey of community rehabilitation service sat-isfaction for the disabled,the difference between the very dissatisfied and very satisfied groups was statistically sig-nificant(P<0.05).Conclusion:taking a secondary gener-al hospital in Changsha city as an example,the treatment methods in secondary general hospitals are still dominated by traditional drug therapy,and the disabled are not sat-isfied with community rehabilitation services.Therefore,rehabilitation treatment projects to meet the rehabilitation needs of the disabled should be promoted in hospitals.

关键词： secondary public hospital community rehabilitation positioning people with disabilities

圆线圈平面磁场分布及其电感的计算与分析研究

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江苏科技信息 2022年第24期39卷 45-49页

作者：张克生江苏安全技术职业学院基础课教学部江苏徐州221011

对于圆形截面的载流圆线圈,当截面半径a远小于平均半径R时,用无限长直圆柱导体模型计算圆线圈内部的磁场,用线电流模型计算圆线圈外部的磁场,得到其所在平面的磁场分布表达式。文章通过数值积分计算,结果表明,当a/R<0.015时,圆线圈内、... 详细信息

对于圆形截面的载流圆线圈,当截面半径a远小于平均半径R时,用无限长直圆柱导体模型计算圆线圈内部的磁场,用线电流模型计算圆线圈外部的磁场,得到其所在平面的磁场分布表达式。文章通过数值积分计算,结果表明,当a/R<0.015时,圆线圈内、外侧面边界处两种模型计算的磁场值非常接近,边界处磁场近似连续变化。利用磁阻传感器实际测量了圆线圈平面的磁场分布,实验结果与计算值十分吻合。根据圆线圈平面磁场分布和诺依曼公式,得到圆线圈电感系数L的积分表达式,对比分析电感系数的3种计算方法,结果表明,当a/R<0.015时,L与R近似成正比,并随a增大而减小。两种数值积分计算的电感系数结果相等,与近似公式计算的误差随着线圈几何尺寸的增加而增大。

关键词：磁场分布数值计算毕奥-萨伐尔定律电感系数诺依曼公式

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新型宽带圆极化超表面天线设计

新乡学院学报 2023年第3期40卷 40-44页

作者：张克生江苏安全技术职业学院基础课教学部江苏徐州221011

提出了一种加载超表面的高增益宽带圆极化天线。天线由菱形贴片阵列超表面和短路圆环缝隙耦合馈电层组成。微带线馈电的短路圆环缝隙产生包含一个轴比最小值点的圆极化辐射,加载超表面后产生另一个轴比极小值点,从而实现宽带圆极化和高... 详细信息

提出了一种加载超表面的高增益宽带圆极化天线。天线由菱形贴片阵列超表面和短路圆环缝隙耦合馈电层组成。微带线馈电的短路圆环缝隙产生包含一个轴比最小值点的圆极化辐射,加载超表面后产生另一个轴比极小值点,从而实现宽带圆极化和高增益特性。通过优化设计,天线在整个尺寸为50 mm×50 mm×2.8 mm(1.08λ0×1.08λ0×0.06λ0)时,具有低剖面特性。天线实测与仿真结果基本吻合,-10 dB阻抗带宽和3 dB轴比带宽分别达到了50.0%和23.1%,在7.1 GHz处峰值增益达9.3 dBic,且在圆极化带宽内增益波动仅有2 dB。

关键词：超表面短路圆环缝隙高增益宽带圆极化天线