Results 81 to 90 of about 12,453 (164)
Quality Evaluation of Nine Varieties of Blueberry Based on Principal Component Analysis [PDF]
To investigate the quality characteristics of different varieties of blueberry, the quality differences on appearance, physicochemical properties, and sugar and acid composition were analyzed.
Gang LIU +9 more
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Gaoya dianqi, 2020 断路器操动机构分合闸线圈电流波形对分析机构已有或潜在机械故障有重要参考意义,由于受外界环境的影响,许多算法在数据采集及波形特征点提取一致性方面存在一定的不足。文中利用零偏置计算、改进后的均值滤波算法对采集到的原始电流波形数据进行预处理以降低外界因素的影响,同时针对不同的特征点,依据其在波形中的特征进行分类,研究相应的特征点提取算法;在此基础上,搭建了断路器分合闸线圈电流信号采集处理系统并完成了相应算法软件的开发,且以某550 k V断路器配套的液压碟簧操动机构为测试样机对算法进行了验证 ...
宋亚凯 +5 more
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Gaoya dianqi, 2021 基于非参数检验的声信号时域特征识别是一种高识别率、小时间开销的高压断路器机械故障诊断方法,但也有无效区间长、特征测量值和检验方法有待优化等问题。对于高压断路器机械故障声信号,根据非参数检验的效果剔除低效区段;利用散布矩阵对比特征测量值的分类能力;搭建高压断路器机械故障试验平台,对采集到的声信号分别进行4种非参数检验,选取特征值并进行机器学习。声信号的纯噪音部分和余震部分被剔除,从而得到有效时域区段;在8种特征测量值中,各种熵的分类能力明显高于均值等传统特征测量值,且Renyi熵的分类能力最好 ...
易林 +6 more
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Establishment and Application of a Quality Evaluation System for Commercial Flavored Extruded Noodles [PDF]
In order to objectively evaluate the quality of commercial flavored extruded noodles and to establish a scientific and reasonable quality evaluation system, 17 quality indexes of 22 types of commercial flavored extruded noodles were measured.
ZHAO Xue, CONG Zhongxiao, SUN Huajun, ZANG Yanqing, LI Changsheng, ZHOU Xuan, QIAN Lili
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Hydrochemical characteristics and component sources of water in underground reservoirs in the Daliuta Coal Mine [PDF]
ObjectiveUnderground reservoirs in coal mines are capable of storing and purifying mine water. A deep understanding of the hydrochemical characteristics and formation mechanisms of water in underground reservoirs is identified as an important ...
Binbin JIANG +6 more
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基于半监督学习的断路器弹簧机构机械特性监测及状态评估技术研究
Gaoya dianqi, 2022 针对断路器弹簧机构机械特性监测及状态识别系统普遍存在监测类型不全、特征值提取单一、判断标准太过绝对等问题，文中提出了基于小波及半监督学习的多特征分析的断路器弹簧操动机构机械状态识别新方法。通过感知元件对分合闸线圈电流、动触头位移等信号进行采集，采用小波算法对信号进行滤波处理，分析断路器弹簧操动机构的分合闸线圈电流、动触头位移等信号与断路器异常状态之间的对应关系，提取特征值，建立半监督学习多分类网络模型，实现断路器弹簧操动机构故障的机械特性监测及状态识别。实验结果验证了此方法具有较高的诊断正确率 ...
彭跃辉 +3 more
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Research Progress of Non-destructive Testing Technology in Beef Quality [PDF]
Beef is rich in nutrients and is one of the favored meats among consumers. Market price, consumer willingness to buy and satisfaction are affected by the quality of beef, so it is important to test the quality of beef.
Hao LIU +8 more
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Research Progress on Geographical Origin Traceability and Authentication of Citri Reticulatae Pericarpium [PDF]
Citri Reticulatae Pericarpium (CRP) has both culinary and medicinal uses, with high medicinal and economic value. However, CRP fraud such as mislabeling of the geographical origin, passing off, and aging time cheating has occurred frequently, which ...
LIU Wenwen, WEI Wan, CHEN Yan, ZHAO Jie, FU Manqin, WANG Xu
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Gaoya dianqi, 2018 根据目前基于100 MS/s超宽带检测实现多局放源识别和干扰抑制依据的局部放电波形特征提取及分类,指出实现此系统的关键技术为脉冲群波形的快速特征提取。其一般通过对脉冲群时、频域波形进行非线性映射,形成特征参数的2D平面或3D空间,再进行无监督聚类分析即可实现局放源间和噪声源的分离。针对目前应用较多的等效时频法,提出了时频自相法和时频熵法,基于指数模型和蒙特卡洛法产生仿真脉冲群,对上述3种时频算子进行了特征参数2D平面和3D空间的可分类性评定。可分类性测度值表明 ...
魏本刚, 姚周飞, 贺林, 李悦
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Gaoya dianqi, 2020 针对气体绝缘金属全封闭开关设备（gas insulated switchgear,GIS）故障频发问题,提出一种基于振动特征估计的GIS设备故障检测与分析方法;首先,提取GIS设备金属外壳振动信号特征并基于通用自回归模型建立系统的状态空间模型;然后,采用粒子滤波算法对GIS设备振动特征进行估计。同时,将特征估计值与实际测量值之间残差的绝对值作为设备故障检测指标,结合自适应阈值方法来检测故障;最后,依据振动特征残差的变化趋势实现机械故障与放电故障的隔离。对多组变电站现场GIS设备不同故障前 ...
赵洪山, 高玉峰
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