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高频真空木材干燥的模糊神经网络控制方法研究

姜滨,孙丽萍,曹军,周正

《中国工程科学》 2014年 第16卷 第4期   页码 17-20

摘要:

高频真空木材干燥是一种干燥速度快、能源消耗低、环境污染小的新型联合干燥技术。在木材高频真空联合干燥过程的理论分析基础上,针对神经网络方法建立的木材干燥模型,设计了木材干燥模糊控制器和模糊神经网络控制器。对模糊控制和模糊神经网络两种控制方法进行了仿真实验,结果表明模糊神经网络方法控制效果更好,如温度上升快,控制精度高,稳定性好。模糊神经网络控制方法对实现木材干燥过程的全自动控制具有重要研究意义。

关键词: 高频真空     木材干燥     模糊神经网络    

Tests on impact effect of partial fracture at steel frame connections

CHEN Yiyi, BIAN Ruoning

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 295-301 doi: 10.1007/s11709-008-0049-z

摘要: Impact effect of sudden fracture at steel frame connections under severe earthquake or other extreme loads is presented in this paper. The relation of impulse caused by structural fracture to the release of inner force at the cracked location, the magnitude of the response to impact on the basis of one degree of freedom model, and the ratio of the peak value of response to natural period of the system are investigated. Two types of fracture tests were designed and carried out both on uniaxial steel bar tensioned and moment resistant steel frame model. It is proven that the response during the fracture process can be measured quite well using high-frequency data processing system. It is also revealed that the instant fracture of structural connection is characterized by progressive and partial fracture. Numerical evaluation of the impact effect of connection fracture is carried out.

关键词: structural fracture     natural     fracture     progressive     high-frequency    

State identification of home appliance with transient features in residential buildings

《能源前沿(英文)》 2022年 第16卷 第1期   页码 130-143 doi: 10.1007/s11708-022-0822-z

摘要: Nonintrusive load monitoring (NILM) is crucial for extracting patterns of electricity consumption of household appliance that can guide users’ behavior in using electricity while their privacy is respected. This study proposes an online method based on the transient behavior of individual appliances as well as system steady-state characteristics to estimate the operating states of the appliances. It determines the number of states for each appliance using the density-based spatial clustering of applications with noise (DBSCAN) method and models the transition relationship among different states. The states of the working appliances are identified from aggregated power signals using the Kalman filtering method in the factorial hidden Markov model (FHMM). Thereafter, the identified states are confirmed by the verification of system states, which are the combination of the working states of individual appliances. The verification step involves comparing the total measured power consumption with the total estimated power consumption. The use of transient features can achieve fast state inference and it is suitable for online load disaggregation. The proposed method was tested on a high-resolution data set such as Labeled hIgh-Frequency daTaset for Electricity Disaggregation (LIFTED) and it outperformed other related methods in the literature.

关键词: nonintrusive load monitoring (NILM)     load disaggregation     online load disaggregation     Kalman filtering     factorial hidden Markov model (FHMM)     Labeled hIgh-Frequency daTaset for Electricity Disaggregation (LIFTED)    

Experimental Study on the Piezoelectric Prestage Driver of Electrohydraulic Servo Valves

CHENG Guang-ming, SHEN Chuan-liang, YANG Zhi-gang

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 56-59 doi: 10.1007/s11465-005-0017-4

摘要:

A piezoelectric actuated prestage driver of hydraulic servo valves for the low-frequency response of electrohydraulic servo valve electromagnetic prestage driver was presented. The new driver was driven by piezoelectric multilayer actuators. The displacement of a piezoelectric multilayer actuator was amplified by a flexure-hinged amplifier based on the principles of triangle amplification. Static and dynamic characteristics were tested on the model machine. The characteristics of good linearity, high resolution, and high-frequency response were approved. The natural frequency reached 1.201 kHz using finite element analysis, and the practice measurement result was 1 kHz.

关键词: flexure-hinged amplifier     kHz     amplification     high-frequency     electromagnetic    

主动源在高频被动源面波测量中的应用 Article

程逢,夏江海,沈超,胡悦,徐宗博,宓彬彬

《工程(英文)》 2018年 第4卷 第5期   页码 685-693 doi: 10.1016/j.eng.2018.08.003

摘要:

被动源面波可弥补主动源面波测量中低频信息缺失的不足,因此引起人们的广泛研究。然而,被动源面波法不能提供高达几十赫兹的相速度信息,因此需要通过主动源面波法拓展频率范围。为了减少野外工作量,本文设计了一种高频被动源面波的勘探策略,即在连续的被动源面波测量过程中引入人工震源。我们称其为“混合源面波”(mixed-source surface-wave,MSW)测量。研究人员分别在学校内、马路边、铁路旁这三个噪声等级不同的地点记录短时长(10 min 内)被动源面波和混合源面波。频谱分析表明,在连续的被动源面波观测中加入人工震源可以改善高频段能量。在记录的时间序列中分别应用了空间自相关(spatial autocorrelation,SPAC)法与基于互相关的被动源面波多道分析方法(multichannel analysis of passive surface,MAPS),结果表明该施工策略在高频段面波相速度分析中有很大的灵活性与适用性。笔者认为,相较于进行单一的主动源面波测量或被动源面波测量,在地震勘探中进行混合源面波测量具有建设性意义。

关键词: 被动源面波     主动源面波     高频     混合源面波     空间自相关     被动源面波多道分析    

智能电网状态估计中用于提高数据完整性的超分辨率感知技术 Article

梁高琪, 刘国龙, 赵俊华, 刘艳丽, 顾津锦, 孙广中, 董朝阳

《工程(英文)》 2020年 第6卷 第7期   页码 789-800 doi: 10.1016/j.eng.2020.06.006

摘要:

智能电网是一个结合了可再生能源与先进信息和通信技术的国家关键基础设施,为社会提供经济且安全的电力供应。为了应对可再生能源的间歇性特点并确保智能电网的安全性,应该进行更高频率的状态估计运算,而高频率的状态估计运算需要更加完整的系统状态信息。本文从智能电网状态估计数据完整性角度出发,将如何基于低频数据恢复高频数据的问题视为一个超分辨率感知(super resolution perception, SRP)问题。然后提出了一种新颖的基于机器学习的SRP方法,即超分辨率状态估计网络(super resolution perception net for state estimation, SRPNSE)来提高状态估计的数据完整性。此方法主要包含三部分:特征提取、信息补全和数据重建。算例证明了我们提出的SRPNSE方法在状态估计中从低频数据恢复至高频数据的有效性和实用价值。

关键词: 状态估计     低频数据     高频数据     超分辨率感知     数据完整性    

Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

《能源前沿(英文)》 2014年 第8卷 第3期   页码 386-393 doi: 10.1007/s11708-014-0323-9

摘要: Accurate modeling and parameters of high voltage (HV) grid are critical for stability research of system frequency. In this paper, simulation modeling of the system frequency was conducted of an interconnected power system with HV transmission lines in China. Based on recorded tripping data of the HV transmission lines, system parameters were identified by using genetic algorithm (GA). The favorable agreement between simulation results and recorded data verifies the validity of gird models and the accuracy of system parameters. The results of this paper can provide reference for the stability research of HV power grid.

关键词: high voltage (HV) grid     frequency stability parameter identification     primary frequency regulation (PFR)    

Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

《机械工程前沿(英文)》 2016年 第11卷 第4期   页码 344-350 doi: 10.1007/s11465-016-0406-x

摘要:

Researchers have investigated direct drive valve for many years to solve problems, such as fluid force imbalance and switching frequency. The structure of the rotary valve has received considerable research interest because of its favorable dynamic properties and simple structure. This paper studied the high frequency double-servo direct drive rotary valve (DDRV), and proposed a novel structure and drive method satisfying high reversing frequency and adequate quantity of flow. Servo motors are integrated into the valve by the innovative structure, which is designed to equilibrate the unbalanced radial fluid force with the symmetric distributed oil ports. Aside from the fast reversing function of the valve, the DDRV presented high performance in linearity of the flow quantity and valve opening as a result of the fan-shaped flow ports. In addition, a computational fluid dynamics (CFD) method based on Fluent was conducted to verify the flux regulation effect of the height change of the adjustable boss.

关键词: direct drive rotary valve     computational fluid dynamics (CFD)     flow regulation    

High frequency group pulse electrochemical machining

WU Gaoyang, ZHANG Zhijing, ZHANG Weimin, TANG Xinglun

《机械工程前沿(英文)》 2007年 第2卷 第3期   页码 293-296 doi: 10.1007/s11465-007-0051-5

摘要: In the process of machining ultrathin metal structure parts, the signal composition of high frequency group pulse, the influence of frequency to reverse current, and the design of the cathode in high frequency group pulse electrochemical machining (HGPECM) are discussed. The experiments on process were carried out. Results indicate that HGPECM can greatly improve the characteristics of the inter-electrode gap flow field, reduce electrode passivation, and obtain high machining quality. The machining quality is obviously improved by increasing the main pulse frequency. The dimensional accuracy reaches 30 40 ?m and the roughness attained is at 0.30 0.35 ?m. High frequency group pulse electrochemical machining can be successfully used in machining micro-parts.

关键词: HGPECM     process     machining quality     passivation     inter-electrode    

High frequency of alternative splicing variants of the oncogene in neuroendocrine tumors of the pancreas

《医学前沿(英文)》   页码 907-923 doi: 10.1007/s11684-023-1009-7

摘要: The characteristic genetic abnormality of neuroendocrine neoplasms (NENs), a heterogeneous group of tumors found in various organs, remains to be identified. Here, based on the analysis of the splicing variants of an oncogene Focal Adhesion Kinase (FAK) in The Cancer Genome Atlas datasets that contain 9193 patients of 33 cancer subtypes, we found that Box 6/Box 7-containing FAK variants (FAK6/7) were observed in 7 (87.5%) of 8 pancreatic neuroendocrine carcinomas and 20 (11.76%) of 170 pancreatic ductal adenocarcinomas (PDACs). We tested FAK variants in 157 tumor samples collected from Chinese patients with pancreatic tumors, and found that FAK6/7 was positive in 34 (75.6%) of 45 pancreatic NENs, 19 (47.5%) of 40 pancreatic solid pseudopapillary neoplasms, and 2 (2.9%) of 69 PDACs. We further tested FAK splicing variants in breast neuroendocrine carcinoma (BrNECs), and found that FAK6/7 was positive in 14 (93.3%) of 15 BrNECs but 0 in 23 non-NEC breast cancers. We explored the underlying mechanisms and found that a splicing factor serine/arginine repetitive matrix protein 4 (SRRM4) was overexpressed in FAK6/7-positive pancreatic tumors and breast tumors, which promoted the formation of FAK6/7 in cells. These results suggested that FAK6/7 could be a biomarker of NENs and represent a potential therapeutic target for these orphan diseases.

关键词: FAK6/7     SRRM4     neuroendocrine neoplasms     pancreas     breast    

甚高频雷达复杂场景中目标高度和多径衰减联合估计 Research Articles

陈胜,赵永波,胡毅立,曹成虎,庞晓娇

《信息与电子工程前沿(英文)》 2022年 第23卷 第6期   页码 937-949 doi: 10.1631/FITEE.2100003

摘要:

由于多径效应的影响,甚高频雷达低角估计是雷达领域难题之一,尤其是在反射条件未知的复杂情况下,低角估计更难解决。针对这一问题,提出一种目标高度和多径衰减联合估计算法。该算法首先利用数据本身的特性估算反射系数幅度,当该幅度估计值很小时,认为没有反射信号,然后将反射系数的相位和直达信号与反射信号之间的相位差当作同一部分,即多径相位衰减,并对其进行搜索。推导了该算法的克拉美罗界。最后,计算机仿真和实测数据处理结果表明,该算法在复杂场景下具有良好估计性能,并且在仅有单次快拍的条件下仍能较好地工作。

关键词: 低角估计;甚高频雷达;复杂场景;多径效应;高度估计    

Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 446-472 doi: 10.1007/s11709-019-0605-8

摘要: The main purpose of the present study is to enhance high-level noisy data by a wavelet-based iterative filtering algorithm for identification of natural frequencies during ambient wind vibrational tests on a petrochemical process tower. Most of denoising methods fail to filter such noise properly. Both the signal-to-noise ratio and the peak signal-to-noise ratio are small. Multiresolution-based one-step and variational-based filtering methods fail to denoise properly with thresholds obtained by theoretical or empirical method. Due to the fact that it is impossible to completely denoise such high-level noisy data, the enhancing approach is used to improve the data quality, which is the main novelty from the application point of view here. For this iterative method, a simple computational approach is proposed to estimate the dynamic threshold values. Hence, different thresholds can be obtained for different recorded signals in one ambient test. This is in contrast to commonly used approaches recommending one global threshold estimated mainly by an empirical method. After the enhancements, modal frequencies are directly detected by the cross wavelet transform (XWT), the spectral power density and autocorrelation of wavelet coefficients. Estimated frequencies are then compared with those of an undamaged-model, simulated by the finite element method.

关键词: ambient vibration test     high level noise     iterative signal enhancement     wavelet     cross and autocorrelation of wavelets    

Alternate partial root-zone irrigation with high irrigation frequency improves root growth and reduces

Shaoqing DU, Ling TONG, Shaozhong KANG, Fusheng LI, Taisheng DU, Sien LI, Risheng DING

《农业科学与工程前沿(英文)》 2018年 第5卷 第2期   页码 188-196 doi: 10.15302/J-FASE-2017176

摘要: Alternate partial root-zone irrigation (APRI) can improve water use efficiency in arid areas. However, the effectiveness and outcomes of different frequencies of APRI on water uptake capacity and physiological water use have not been reported. A two-year field experiment was conducted with two irrigation amounts (400 and 500 mm) and three irrigation methods (conventional irrigation, APRI with high and low frequencies). Root length density, stomatal conductance, photosynthetic rate, transpiration rate, leaf water use efficiency, midday stem and leaf water potentials were measured. The results show that in comparison with conventional irrigation, APRI with high frequency significantly increased root length density and decreased water potentials and stomatal conductance. No differences in the above indicators between the two APRI frequencies were detected. A significantly positive relationship between stomatal conductance and root length density was found under APRI. Overall, alternate partial root-zone irrigation with high frequency has a great potential to promote root growth, expand water uptake capacity and reduce unproductive water loss in the arid apple production area.

关键词: alternate partial root-zone irrigation     apple tree     leaf water use efficiency     root length density     stomatal conductance     water potential    

复杂机械结构中高频动响应能量有限元方法研究

祝丹晖,解妙霞,孔祥杰,张文博,陈花玲

《中国工程科学》 2013年 第15卷 第1期   页码 106-112

摘要:

从理论研究和应用研究两个方面追踪了国内外关于能量有限元的发展现状,并指出能量有限元已趋向于预示越来越复杂的结构动响应;接下来介绍本课题组近年来利用能量有限元方法针对实际复杂结构及复杂载荷环境中的高频动响应问题所做的研究工作,主要包括3个部分:一是在考虑多种传递波功率流耦合的情况下,发展了圆柱壳、截锥壳等复杂结构的高频响应能量有限元方法,从而得到了此类结构的中高频局部动响应特性;二是考虑在脉动载荷、混响室等复杂环境中,利用能量有限元方法并结合能量边界元方法预示了结构的高频振动特性和声振耦合特性;三是开发了能量有限元的计算软件,为其大规模应用奠定了基础。最后指出了能量有限元方法目前存在的问题和进一步研究的方向。

关键词: 中高频响应     能量有限元方法     声振响应预示     机械结构     动力学    

Comparative study of oscillating flow characteristics of cryocooler regenerator at low temperatures

Yonglin JU , Qingqing SHEN ,

《能源前沿(英文)》 2009年 第3卷 第1期   页码 80-84 doi: 10.1007/s11708-009-0008-y

摘要: A brief review is presented on previous experimental results and correlations on the friction factor of cryocooler regenerators operating at oscillating flow and pulsating pressure conditions, for different mesh sizes of packed woven screens, focusing on the effects of different operating frequencies ranging from 20 to 80 Hz, at room and cryogenic temperatures. A comparison of the friction factor data with those of other studies is presented to clarify the reason for the difference. Finally, a new oscillating flow correlation of regenerators, in terms of several non-dimensional parameters, is discussed and compared.

关键词: friction factor     regenerator     oscillating flow     high frequency    

标题 作者 时间 类型 操作

高频真空木材干燥的模糊神经网络控制方法研究

姜滨,孙丽萍,曹军,周正

期刊论文

Tests on impact effect of partial fracture at steel frame connections

CHEN Yiyi, BIAN Ruoning

期刊论文

State identification of home appliance with transient features in residential buildings

期刊论文

Experimental Study on the Piezoelectric Prestage Driver of Electrohydraulic Servo Valves

CHENG Guang-ming, SHEN Chuan-liang, YANG Zhi-gang

期刊论文

主动源在高频被动源面波测量中的应用

程逢,夏江海,沈超,胡悦,徐宗博,宓彬彬

期刊论文

智能电网状态估计中用于提高数据完整性的超分辨率感知技术

梁高琪, 刘国龙, 赵俊华, 刘艳丽, 顾津锦, 孙广中, 董朝阳

期刊论文

Parameter identification of interconnected power system frequency after trip-out of high voltage transmission

Xuzhan ZHOU,Shanshan LIU,Mingkun WANG,Yiping DAI,Yaohua TANG

期刊论文

Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

期刊论文

High frequency group pulse electrochemical machining

WU Gaoyang, ZHANG Zhijing, ZHANG Weimin, TANG Xinglun

期刊论文

High frequency of alternative splicing variants of the oncogene in neuroendocrine tumors of the pancreas

期刊论文

甚高频雷达复杂场景中目标高度和多径衰减联合估计

陈胜,赵永波,胡毅立,曹成虎,庞晓娇

期刊论文

Wavelet-based iterative data enhancement for implementation in purification of modal frequency for extremely

Hassan YOUSEFI, Alireza TAGHAVI KANI, Iradj MAHMOUDZADEH KANI, Soheil MOHAMMADI

期刊论文

Alternate partial root-zone irrigation with high irrigation frequency improves root growth and reduces

Shaoqing DU, Ling TONG, Shaozhong KANG, Fusheng LI, Taisheng DU, Sien LI, Risheng DING

期刊论文

复杂机械结构中高频动响应能量有限元方法研究

祝丹晖,解妙霞,孔祥杰,张文博,陈花玲

期刊论文

Comparative study of oscillating flow characteristics of cryocooler regenerator at low temperatures

Yonglin JU , Qingqing SHEN ,

期刊论文