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氟改性Co-Mo/TiO_2催化剂的加氢脱硫活性与反应动力学的研究 被引量:19
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作者 王丹红 李伟 +2 位作者 陶克毅 沈炳龙 李定一 《石油学报(石油加工)》 EI CAS CSCD 北大核心 1998年第4期12-16,共5页
以脉冲微型反应器和色谱联用的方法,研究了以γ-Al2O3、TiO2及F改性TiO2为载体的Co-Mo催化剂的加氢脱硫活性及反应动力学。结果表明,以TiO2为载体的催化剂活性远高于以γ-Al2O3为载体的催化剂。从动力... 以脉冲微型反应器和色谱联用的方法,研究了以γ-Al2O3、TiO2及F改性TiO2为载体的Co-Mo催化剂的加氢脱硫活性及反应动力学。结果表明,以TiO2为载体的催化剂活性远高于以γ-Al2O3为载体的催化剂。从动力学角度看,这是由于其活化能明显低于后者的缘故;F对TiO2载体改性后催化剂的加氢脱硫表观反应速率常数明显提高,使得催化剂的活性得到较大改善。 展开更多
关键词 氟改性 TiO2载体 加氢脱硫 重油 渣油
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加氢脱硫催化剂载体的研究进展 被引量:16
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作者 仝建波 蔺阳 +2 位作者 刘淑玲 温俊涛 刘瑛瑛 《化工进展》 EI CAS CSCD 北大核心 2014年第5期1170-1179,共10页
综述了加氢脱硫催化剂载体的研究现状及其发展趋势,分别从单组分载体、复合氧化物载体、分子筛和改性载体4个方面论述了加氢脱硫催化剂载体各自的优缺点。单组分载体重点介绍了A12O3、TiO2、炭载体;复合氧化物载体主要对铝基、钛基二元... 综述了加氢脱硫催化剂载体的研究现状及其发展趋势,分别从单组分载体、复合氧化物载体、分子筛和改性载体4个方面论述了加氢脱硫催化剂载体各自的优缺点。单组分载体重点介绍了A12O3、TiO2、炭载体;复合氧化物载体主要对铝基、钛基二元复合氧化物以及三元复合氧化物载体进行了综述;并且对以MCM-41、SBA-15和KIT为代表的介孔分子筛做了介绍;还描述了近年来以改性MCM-41、SBA-15、活性炭为主要研究对象的改性的分子筛。最后指出改性载体尤其是改性分子筛将是未来研究的焦点。 展开更多
关键词 加氢脱硫 催化剂载体 单组分载体 复合氧化物载体 分子筛 改性载体
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HAL1 mediate salt adaptation in Arabidopsis thaliana 被引量:13
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作者 YangSX ZhaoYX 《Cell Research》 SCIE CAS CSCD 2001年第2期142-148,共7页
The yeast HAL1 gene was introduced into Arabidopsis thaliana by Agrobacterium tumefaciens-mediated transformation with vacuum infiltration under the control of CaMV 35S promoter. Thirty-three individual kanamycin resi... The yeast HAL1 gene was introduced into Arabidopsis thaliana by Agrobacterium tumefaciens-mediated transformation with vacuum infiltration under the control of CaMV 35S promoter. Thirty-three individual kanamycin resistant plants were obtained from 75,000 seeds. Southern blotting analysis indicated that HAL1 gene had been integrated into all of the transgenic plants’ genomes. The copy number of HAL1 gene in transgenic plants was mostly 1 to 3 by Southern analysis. Phenotypes of transgenic plants have no differences with wild type plants. several samples of transformants were self-pollinated, and progenies from transformed and non-transformed plants (controls) were evaluated for salt tolerance and gene expression. Measurement of concentrations of intracellular K+ and Na+ showed that transgenic lines were able to retain less Na+ than that of the control under salt stress. Results from different tests indicated the expression of HAL1 gene promotes a higher level of salt tolerance in vivo in the transgenic Arabidopsis plants. 展开更多
关键词 Saccharomyces cerevisiae Proteins Adaptation Physiological Arabidopsis Dose-Response Relationship Drug Fungal Proteins Gene Expression Regulation Plant Genetic Engineering GERMINATION Homeostasis PHENOTYPE Plants Genetically modified Potassium RNA Messenger Regeneration Research support Non-U.S. Gov't Rhizobium radiobacter SALTS Sodium Sodium Chloride Transformation Genetic
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Thansgenic peanut plants obtained by particle bombardment via somatic embryogenesis regeneration system 被引量:12
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作者 DengXY WeiYZ 《Cell Research》 SCIE CAS CSCD 2001年第2期156-160,共5页
After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resist... After pre-culture and treatment of osmosis, cotyledons of immature peanut (Arachis hypogaea L.) zygotic embryos were transformed via particle bombardment with a plasmid containing a chimeric hph gene conferring resistance to hygromycin and a chimeric intron-gus gene. Selection for hygromycin resistant calluses and somatic embryos was initiated at 10th d post-bombardment on medium containing 10-25 mg/L hygromycin. Under continuous selection, hygromycin resistant plantlets were regenerated from somatic embryos and were recovered from nearly 1.6% of the bombarded cotyledons. The presence and integration of foreign DNA in regenerated hygromycin resistant plants was confirmed by PCR (polymerase chain reaction) for the intron-gus gene and by Southern hybridization of the hph gene. GUS enzyme activity was detected in leaflets from transgenic plants but not from control, non-transformed plants. The production of transgenic plants are mainly based on a newly improved somatic embryogenesis regeneration system developed by us. 展开更多
关键词 CINNAMATES Anti-Bacterial Agents Arachis hypogaea Cell Culture Techniques CHIMERA COTYLEDON Drug Resistance Gene Expression Regulation Plant Genetic Engineering Hygromycin B Osmosis Plants Genetically modified Plasmids Regeneration Research support Non-U.S. Gov't Seeds Transformation Genetic
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Enhanced Wolf Pack Algorithm (EWPA) and Dense-kUNet Segmentation for Arterial Calcifications in Mammograms
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作者 Afnan M.Alhassan 《Computers, Materials & Continua》 SCIE EI 2024年第2期2207-2223,共17页
Breast Arterial Calcification(BAC)is a mammographic decision dissimilar to cancer and commonly observed in elderly women.Thus identifying BAC could provide an expense,and be inaccurate.Recently Deep Learning(DL)method... Breast Arterial Calcification(BAC)is a mammographic decision dissimilar to cancer and commonly observed in elderly women.Thus identifying BAC could provide an expense,and be inaccurate.Recently Deep Learning(DL)methods have been introduced for automatic BAC detection and quantification with increased accuracy.Previously,classification with deep learning had reached higher efficiency,but designing the structure of DL proved to be an extremely challenging task due to overfitting models.It also is not able to capture the patterns and irregularities presented in the images.To solve the overfitting problem,an optimal feature set has been formed by Enhanced Wolf Pack Algorithm(EWPA),and their irregularities are identified by Dense-kUNet segmentation.In this paper,Dense-kUNet for segmentation and optimal feature has been introduced for classification(severe,mild,light)that integrates DenseUNet and kU-Net.Longer bound links exist among adjacent modules,allowing relatively rough data to be sent to the following component and assisting the system in finding higher qualities.The major contribution of the work is to design the best features selected by Enhanced Wolf Pack Algorithm(EWPA),and Modified Support Vector Machine(MSVM)based learning for classification.k-Dense-UNet is introduced which combines the procedure of Dense-UNet and kU-Net for image segmentation.Longer bound associations occur among nearby sections,allowing relatively granular data to be sent to the next subsystem and benefiting the system in recognizing smaller characteristics.The proposed techniques and the performance are tested using several types of analysis techniques 826 filled digitized mammography.The proposed method achieved the highest precision,recall,F-measure,and accuracy of 84.4333%,84.5333%,84.4833%,and 86.8667%when compared to other methods on the Digital Database for Screening Mammography(DDSM). 展开更多
关键词 Breast arterial calcification cardiovascular disease semantic segmentation transfer learning enhanced wolf pack algorithm and modified support vector machine
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Direct gas-phase epoxidation of propylene to propylene oxide using air as oxidant on supported gold catalyst 被引量:4
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作者 Zhanghuai Suo Mingshan Jin +2 位作者 Jiqing Lu Zhaobin Wei Can Li 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2008年第2期184-190,共7页
Gold catalysts supported on SiO2, TiO2, TiO2-SiO2, and ZrO2-SiO2 supports were prepared by impregnating each support with a basic solution of tetrachloroauric acid. X-ray diffraction (XRD), transmission electron mic... Gold catalysts supported on SiO2, TiO2, TiO2-SiO2, and ZrO2-SiO2 supports were prepared by impregnating each support with a basic solution of tetrachloroauric acid. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize their structure and surface composition. The results indicated that the size of gold particles could be controlled to below 10 nm by this method of preparation. Washing gold catalysts with water could markedly enhance the dispersion of metallic gold particles on the surface, but it could not completely remove the chloride ions left on the surface. The catalytic performance of direct vapor-phase epoxidation of propylene using air as an oxidant over these catalysts was evaluated at atmospheric pressure. The selectivity to propylene oxide (PO) was found to vary with reaction time on the stream. At the reaction conditions of atmosphere pressure, temperature 325 ℃, feed gas ratio V(C3H6)/V(O2)= 1/2, and GHSV =6000h^-1, 17.9% PO selectivity with 0.9% propylene conversion were obtained at initial 10 min for Au/SiO2 catalyst. After reacting 60 min only 8.9% PO selectivity were detected, but the propylene conversion rises to 1.4% and the main product is transferred to acrolein (72% selectivity). Washing Au/TiO2-SiO2 and Aa/ZrO2-SiO2 samples with magnesium citrate solution could markedly enhance the activity and PO selectivity because smaller gold particles were obtained. 展开更多
关键词 gold catalyst support modified impregnation method epoxidation of propylene molecular oxygen
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Enhanced catalytic performance of Cu-and/or Mn-loaded Fe-Sep catalysts for the oxidation of CO and ethyl acetate 被引量:2
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作者 Lisha Liu Yong Song +4 位作者 Zhidan Fu Qing Ye Shuiyuan Cheng Tianfang Kang Hongxing Dai 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第10期1427-1434,共8页
The Fe-modi fied sepiolite-supported Mn–Cu mixed oxide(Cux Mny/Fe-Sep) catalysts were prepared using the co-precipitation method.These materials were characterized by means of the XRD,N_2 adsorption–desorption,XPS,H... The Fe-modi fied sepiolite-supported Mn–Cu mixed oxide(Cux Mny/Fe-Sep) catalysts were prepared using the co-precipitation method.These materials were characterized by means of the XRD,N_2 adsorption–desorption,XPS,H_2-TPR,and O_2-TPD techniques,and their catalytic activities for CO and ethyl acetate oxidation were evaluated.The results show that catalytic activities of the Cux Mny/Fe-Sep samples were higher than those of the Cu1/Fe-Sep and Mn2/Fe-Sep samples,and the Mn/Cu molar ratio had a distinct in fluence on catalytic activity of the sample.Among the Cux Mny/Fe-Sep and Cu1Mn2/Sep samples,Cu1Mn2/Fe-Sep performed the best for CO and ethyl acetate oxidation,showing the highest reaction rate and the lowest T50 and T90 of 4.4×10^(-6) mmol·g-1·s-1,110,and 140 °C for CO oxidation,and 1.9×10^(-6) mmol·g-1·s-1,170,and210 °C for ethyl acetate oxidation,respectively.Moreover,the Cu1Mn2/Fe-Sep sample possessed the best lowtemperature reducibility and the lowest temperature of oxygen desorption as well as the highest surface Mn^(4+)/Mn^(3+) and Cu^(2+)/CuO atomic ratios.It is concluded that factors,such as the strong interaction between the Cu or Mn and the Fe-Sep support,good low-temperature reducibility,and good mobility of chemisorbed oxygen species,might account for the excellent catalytic activity of Cu1Mn2/Fe-Sep. 展开更多
关键词 Fe-modified sepiolite supported Mn–Cu mixed oxide Reducibility Strong metal-support interaction CO oxidation Ethyl acetate oxidation
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PtSn-Mg(Zn)AlO催化剂应用于乙烷脱氢反应研究 被引量:2
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作者 吴小平 王晨光 +3 位作者 张琦 刘琪英 张兴华 马隆龙 《化工学报》 EI CAS CSCD 北大核心 2019年第11期4268-4277,共10页
采用阴离子交换法合成了一系列不同Zn和Pt含量的PtSn-Mg (Zn) AlO催化剂用于乙烷脱氢反应。实验结果表明,在水滑石载体中掺杂少量的Zn对乙烷脱氢反应有明显影响。当Zn含量为2%(质量)时Pt基催化剂活性性能最优,在550℃时乙烷初始转化率达... 采用阴离子交换法合成了一系列不同Zn和Pt含量的PtSn-Mg (Zn) AlO催化剂用于乙烷脱氢反应。实验结果表明,在水滑石载体中掺杂少量的Zn对乙烷脱氢反应有明显影响。当Zn含量为2%(质量)时Pt基催化剂活性性能最优,在550℃时乙烷初始转化率达到27.1%,2 h平均转化率为21.6%。BET和SEM结果表明PtSn-Mg(Zn) AlO催化剂比PtSn-MgAlO催化剂比表面积更大,TEM结果显示,PtSn-Mg(Zn) AlO催化剂和PtSn-MgAlO催化剂的金属颗粒的平均直径分别为(1.49±0.31) nm和(2.0±0.23) nm,说明Zn的掺杂在一定程度上改变了催化剂的结构,能减小Pt颗粒的尺寸,更好地分散Pt颗粒,从而改善乙烷催化脱氢反应性能。此外,考察温度对乙烷脱氢反应性能影响,发现温度越高乙烷初始转化率越高,但催化剂越易失活;考察Pt负载量对乙烷脱氢反应性能的影响,发现增加Pt含量并不能使乙烷转化率得到相应倍数的增加,即增加Pt含量反而使Pt的利用率降低了,因此适量降低PtSn-Mg(2-Zn) AlO催化剂中Pt含量对研究乙烷脱氢反应有深远意义。 展开更多
关键词 化学过程 Zn改性 催化剂载体 镁铝水滑石 催化剂 PTSN 乙烷脱氢
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Process of Patients Telling Children about Newly Diagnosed Breast Cancer
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作者 Ikue Shiino Kumi Suzuki 《Open Journal of Nursing》 2020年第6期598-612,共15页
<strong>Objective:</strong> This study aims to determine the process of patients with newly diagnosed breast cancer in Japan telling their children about the disease, and how they have thought about it aft... <strong>Objective:</strong> This study aims to determine the process of patients with newly diagnosed breast cancer in Japan telling their children about the disease, and how they have thought about it after the diagnosis. <strong>Methods:</strong> Semi-structured interviews were conducted with 15 patients with newly diagnosed breast cancer who had 3- to 14-year-old children. Narratives of participants about how they told their children about the disease were analysed by a qualitative and descriptive study design using the Modified Grounded Theory Approach (M-GTA). <strong>Results:</strong> In the process by which patients with newly diagnosed breast cancer tell their children about the disease, participants were [Maintaining mental balance in the face of the threat of the cancer] after the breast cancer diagnosis, and used the “Facing the cancer through the relationship with the children” as the core category in the process. The participants had [Determined to tell the children about the disease], while [Being worried about the influence of cancer on the children], [Thinking about the benefits of not hiding the cancer], and [Feeling difficulty in communicating the diagnosis of cancer to their children]. They were [Encouraged to tell about the disease to the children] by people around them, and did tell the children that they had a “disease” or “cancer”. The participants who told the children that they had the disease while [Determining the impact on the children] repeated the [Making herself look unconcerned] in the process. Those who told the children that they had cancer while [Determining the impact on the children] repeated [Talking openly about cancer and death] between parents and children. <strong>Conclusions:</strong> The participants came to face their own cancer by maintaining mental balance in the face of the threat of the cancer and telling their children about the disease. Nurses need to assist these patients to be able to deal openly with their children from the early stage of the diagn 展开更多
关键词 Breast Cancer Telling Children Relationship with the Children Family support modified Grounded Theory Approach
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Modified Differential Box Counting in Breast Masses for Bioinformatics Applications
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作者 S.Sathiya Devi S.Vidivelli 《Computers, Materials & Continua》 SCIE EI 2022年第2期3049-3066,共18页
Breast cancer is one of the common invasive cancers and stands at second position for death after lung cancer.The present research work is useful in image processing for characterizing shape and gray-scale complexity.... Breast cancer is one of the common invasive cancers and stands at second position for death after lung cancer.The present research work is useful in image processing for characterizing shape and gray-scale complexity.The proposed Modified Differential Box Counting(MDBC)extract Fractal features such as Fractal Dimension(FD),Lacunarity,and Succolarity for shape characterization.In traditional DBC method,the unreasonable results obtained when FD is computed for tumour regions with the same roughness of intensity surface but different gray-levels.The problem is overcome by the proposedMDBCmethod that uses box over counting and under counting that covers the whole image with required scale.In MDBC method,the suitable box size selection and Under Counting Shifting rule computation handles over counting problem.An advantage of the model is that the proposed MDBC work with recently developed methods showed that our method outperforms automatic detection and classification.The extracted features are fed to K-Nearest Neighbour(KNN)and Support Vector Machine(SVM)categorizes the mammograms into normal,benign,and malignant.The method is tested on mini MIAS datasets yields good results with improved accuracy of 93%,whereas the existing FD,GLCM,Texture and Shape feature method has 91%accuracy. 展开更多
关键词 Breast cancer computer-aided diagnosis K-nearest neighbour MAMMOGRAMS modified differential box counting support vector machine
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柴油车排气颗粒物净化催化剂热稳定性的研究
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作者 陈碧红 杨咏梅 +3 位作者 梁红 李树华 钟志剑 廖锦东 《广州大学学报(自然科学版)》 CAS 2007年第6期83-85,共3页
在γ-Al2O3上负载铈锆涂层,用分步浸渍法负载Cu、K、V等活性组分制备催化剂,研究了铈锆比、铈锆掺杂量和铈锆涂层的焙烧温度及老化温度等条件对催化剂性能的影响.研究发现,载体的改性对催化剂整体的催化性能有较大影响,催化剂的热稳定... 在γ-Al2O3上负载铈锆涂层,用分步浸渍法负载Cu、K、V等活性组分制备催化剂,研究了铈锆比、铈锆掺杂量和铈锆涂层的焙烧温度及老化温度等条件对催化剂性能的影响.研究发现,载体的改性对催化剂整体的催化性能有较大影响,催化剂的热稳定性得到了较大的提高.当铈锆比为1∶1,负载量为20%,焙烧温度为800℃时,催化剂不仅有较好的催化燃烧活性,而且表现出良好的热稳定性. 展开更多
关键词 柴油车 颗粒物 催化剂 载体改性 热稳定性
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改性水泥注浆液的性能及其在巷道加固中的应用
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作者 郭帅帅 曾锋 苏华友 《西南科技大学学报》 CAS 2017年第3期55-59,70,共6页
水泥注浆可以有效控制巷道变形,但可注性较差。为了解决这一问题,向水泥中添加一种外加剂。通过对不同配比改性浆液做流动度、黏度、凝结时间、析水率和抗压强度试验,得到当外加剂掺量(质量分数)为5%,水灰比为0.5时,浆液的可注性和注浆... 水泥注浆可以有效控制巷道变形,但可注性较差。为了解决这一问题,向水泥中添加一种外加剂。通过对不同配比改性浆液做流动度、黏度、凝结时间、析水率和抗压强度试验,得到当外加剂掺量(质量分数)为5%,水灰比为0.5时,浆液的可注性和注浆质量均较好,满足施工要求。将试验结果应用到某矿1110巷道加固工程中,结果表明改性浆液能有效控制巷道变形,提高巷道支护的稳定性,大幅度减少巷道返修率。 展开更多
关键词 改性水泥注浆液 注浆加固 巷道支护 外加剂 注浆液性能
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基于聚类改进S变换与直接支持向量机的电能质量扰动识别 被引量:32
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作者 徐志超 杨玲君 李晓明 《电力自动化设备》 EI CSCD 北大核心 2015年第7期50-58,73,共10页
针对电能质量扰动信号的识别问题,提出基于聚类改进S变换与直接支持向量机(SVM)的电能质量扰动识别方法。提出聚类改进S变换方法,该方法结合电能质量扰动信号的特点,可同时对基频的时域分辨率及高频的频域分辨率进行最优化处理,保证特... 针对电能质量扰动信号的识别问题,提出基于聚类改进S变换与直接支持向量机(SVM)的电能质量扰动识别方法。提出聚类改进S变换方法,该方法结合电能质量扰动信号的特点,可同时对基频的时域分辨率及高频的频域分辨率进行最优化处理,保证特征提取的准确性;将直接支持向量机作为分类器,与最小二乘支持向量机相比,其求解简单,计算复杂度较低,训练与测试速度快,泛化能力较高,并且避免不能保证全局最优解的缺点;将聚类改进S变换与直接支持向量机相结合,应用于单一扰动及混合扰动的识别分类工作。仿真实验验证了所提方法的有效性。 展开更多
关键词 电能质量 扰动识别 聚类改进S变换 直接支持向量机 支持向量机
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基于振动信号的低压万能式断路器分合闸故障程度评估方法的研究 被引量:31
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作者 孙曙光 张强 +2 位作者 杜太行 王景芹 王岩 《中国电机工程学报》 EI CSCD 北大核心 2017年第18期5473-5482,共10页
目前设备的机械故障诊断技术的研究多限于定性诊断,而故障诊断中故障程度的定量评估更能有效的指导设备维护。该文提出了一种低压万能式断路器分合闸故障程度定量评估的方法。首先对断路器工作模式进行识别,即利用局部均值分解(local me... 目前设备的机械故障诊断技术的研究多限于定性诊断,而故障诊断中故障程度的定量评估更能有效的指导设备维护。该文提出了一种低压万能式断路器分合闸故障程度定量评估的方法。首先对断路器工作模式进行识别,即利用局部均值分解(local mean decomposition,LMD)将采集到的分合闸振动信号自适应分解,求取主要乘积函数(product function,PF)的改进多尺度排列熵(multi-scale permutation entropy,MMPE)构成特征向量,再经过降维后,作为改进支持向量机(support vector machine,SVM)的输入量,实现断路器工作模式的识别;当断路器处于故障模式时,对采集的振动信号求取多尺度排列熵偏均值(partial mean of multi-scale permutation entropy,PMMPE),作为故障程度定量评估指标,并参照所求得的不同故障模式的故障程度特性曲线,可实现分合闸故障程度的定量评估。经实测数据验证表明,所提方法可以完成断路器工作模式的有效识别,且PMMPE指标相较于峭度、能量和多尺度排列熵平均值指标,能够更加有效的完成低压万能式断路器分合闸故障程度的定量评估。 展开更多
关键词 低压万能式断路器 局部均值分解(LMD) 改进多尺度排列熵(MMPE) 支持向量机(SVM) 多尺度排列熵偏 均值(PMMPE)故障程度评估
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加减八珍汤联合营养支持治疗老年骨骼肌减少症疗效观察 被引量:29
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作者 梁清月 王仲 +1 位作者 刘戎 刁燕青 《中国中西医结合杂志》 CAS CSCD 北大核心 2019年第7期821-825,共5页
目的观察加减八珍汤联合营养支持对老年骨骼肌减少症的临床疗效及患者生活质量的影响。方法选取2017年3月-2018年3月就诊的214例老年骨骼肌减少症患者作为研究对象,按照随机数字表法将其分为对照组和试验组,每组107例。两组均给予营养... 目的观察加减八珍汤联合营养支持对老年骨骼肌减少症的临床疗效及患者生活质量的影响。方法选取2017年3月-2018年3月就诊的214例老年骨骼肌减少症患者作为研究对象,按照随机数字表法将其分为对照组和试验组,每组107例。两组均给予营养支持干预,进行适当的体育锻炼,试验组患者加服加减八珍汤,总疗程为3个月。观察两组患者中医证候积分及临床疗效,检测患者治疗前后肌肉力量、肌肉质量、肌肉功能,观察患者治疗前后患者生活质量指标如握力、步速、骨骼肌指数(ASMI)、工具性日常生活能力(IADL)和日常生活活动能力(ADL)。结果试验组患者总有效率(95.2%)高于对照组(69.6%,P<0.01)。与本组治疗前比较,两组治疗后证候积分降低(P<0.05),肌肉功能提高(P<0.05),握力、步速、IADL及ADL升高(P<0.05)。与对照组同期比较,试验组治疗后证候积分降低(P<0.01),肌肉功能提高(P<0.05),步速、ADL升高(P<0.01,P<0.05)。结论加减八珍汤联合营养支持治疗老年骨骼肌减少症可明显改善患者的肌肉力量、肌肉质量、肌肉功能,有效提升患者的生活质量。 展开更多
关键词 加减八珍汤 营养支持 老年骨骼肌减少症 生活质量
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基于EEMD和MFFOA-SVM滚动轴承故障诊断 被引量:20
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作者 何青 褚东亮 毛新华 《中国机械工程》 EI CAS CSCD 北大核心 2016年第9期1191-1197,共7页
针对滚动轴承发生故障时,振动信号的时域和频域特征都会发生变化的特点,提出了基于集合经验模态分解(EEMD)、改进果蝇优化算法(MFFOA)和支持向量机(SVM)的滚动轴承故障诊断方法。该方法主要是利用EEMD方法对故障信号进行分解,并计算各IM... 针对滚动轴承发生故障时,振动信号的时域和频域特征都会发生变化的特点,提出了基于集合经验模态分解(EEMD)、改进果蝇优化算法(MFFOA)和支持向量机(SVM)的滚动轴承故障诊断方法。该方法主要是利用EEMD方法对故障信号进行分解,并计算各IMF分量的均方根值和重心频率,以此进行归一化处理得到特征向量。为了提高诊断精度,采用果蝇优化算法优化SVM参数,建立MFFOA-SVM模型,然后对提取的特征向量进行训练与测试,从而识别故障与否及发生点蚀故障的程度。利用该方法对实测信号进行分析与诊断,并与遗传算法的优化结果进行对比,验证了该方法的有效性,说明其具有良好的应用前景。 展开更多
关键词 集合经验模态分解 改进果蝇优化算法 支持向量机 滚动轴承 故障诊断
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基于改进S变换和贝叶斯相关向量机的电能质量扰动识别 被引量:14
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作者 沈跃 刘国海 刘慧 《控制与决策》 EI CSCD 北大核心 2011年第4期587-591,共5页
提出一种改进S变换和相关向量机相结合的电能质量扰动分类法.首先通过引入调节因子构建时频分辨率可控的改进S变换,从而提取各类扰动信号的时频特性;然后利用层次分类法与最小输出编码法构建贝叶斯相关向量机多级分类树模型,实现电能质... 提出一种改进S变换和相关向量机相结合的电能质量扰动分类法.首先通过引入调节因子构建时频分辨率可控的改进S变换,从而提取各类扰动信号的时频特性;然后利用层次分类法与最小输出编码法构建贝叶斯相关向量机多级分类树模型,实现电能质量扰动信号的分类与识别.研究表明,该方法能在强噪声背景下获得高精度的扰动分类识别率,具备比S变换更高的时频分析能力,较支持向量机需要更少的相关向量数目,测试时间更短. 展开更多
关键词 电能质量 扰动识别 改进S变换 相关向量机 支持向量机
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交流接触器触头系统运动分析及故障诊断研究 被引量:14
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作者 刘树鑫 宋健 +2 位作者 刘洋 曹云东 李静 《电工技术学报》 EI CSCD 北大核心 2021年第S02期477-486,共10页
为了解决现有交流接触器触头系统故障诊断技术存在的运行状态识别率较低的问题,该文以改进多尺度排列熵(MMPE)与能量矩为特征向量,提出一种基于粒子群优化(PSO)算法最小二乘支持向量机(LSSVM)的交流接触器触头系统运动分析及故障诊断方... 为了解决现有交流接触器触头系统故障诊断技术存在的运行状态识别率较低的问题,该文以改进多尺度排列熵(MMPE)与能量矩为特征向量,提出一种基于粒子群优化(PSO)算法最小二乘支持向量机(LSSVM)的交流接触器触头系统运动分析及故障诊断方法,能够有效提高运行状态识别率。经实测数据验证表明,所提方法可以完成交流接触器运行状态的有效识别,能够更有效地完成交流接触器故障定性诊断,并可以有针对性地对设备进行检修和维护。 展开更多
关键词 交流接触器 改进多尺度排列熵 能量矩 粒子群优化-最小二乘支持向量机 故障诊断
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基于MEEMD和GA-SVM的列车车轮多边形故障识别方法 被引量:13
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作者 陈博 陈光雄 《噪声与振动控制》 CSCD 2018年第3期157-161,197,共6页
根据列车车轮振动信号的非平稳特性,提出一种基于改进的集合经验模态分解(MEEMD)和遗传算法支持向量机(GA-SVM)的诊断方法,用于识别车轮多边形故障。该方法对车轮轴箱垂向振动信号进行MEEMD分解,依据各固有模态函数(IMF)分量的峭度值和... 根据列车车轮振动信号的非平稳特性,提出一种基于改进的集合经验模态分解(MEEMD)和遗传算法支持向量机(GA-SVM)的诊断方法,用于识别车轮多边形故障。该方法对车轮轴箱垂向振动信号进行MEEMD分解,依据各固有模态函数(IMF)分量的峭度值和能量值选取出主要IMF分量。利用希尔伯特变换求取主要IMF分量的包络谱,并计算包络谱熵。将包络谱熵值归一化后作为特征向量输入GA-SVM中进行训练和识别。对实测信号进行分析的结果表明该方法能有效识别出车轮多边形故障,识别准确率可达到95%。 展开更多
关键词 振动与波 车轮多边形识别 改进的集合经验模态分解 遗传算法支持向量机 包络谱熵
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机床主轴热关键点选择与典型转速热误差预测 被引量:8
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作者 郭世杰 张学炜 +2 位作者 张楠 乔冠 唐术锋 《吉林大学学报(工学版)》 EI CAS CSCD 北大核心 2023年第1期72-81,共10页
针对机床主轴热误差对准静态精度影响的关键问题,提出了一种基于改进鸡群优化(MCSO)算法及支持向量(SVM)的热误差预测模型。利用基于非监督学习的谱聚类与Spearman关联分析辨识主轴关键敏感温度测点,降低温度数据分布于数量的依赖,削弱... 针对机床主轴热误差对准静态精度影响的关键问题,提出了一种基于改进鸡群优化(MCSO)算法及支持向量(SVM)的热误差预测模型。利用基于非监督学习的谱聚类与Spearman关联分析辨识主轴关键敏感温度测点,降低温度数据分布于数量的依赖,削弱温度变量间的多重共线性。引入Levy飞行策略至母鸡个体局部搜索过程,构建了非线性动态自适应惯性权重更新雏鸡策略,基于MCSO-SVM进行核函数、罚因子以及偏差量的全局优化,分别采用MCSO-SVM、BP-GA、GA-SVM和CSO-SVM热误差建模,同时对不同转速下的模型预测能力进行对比分析。热误差实验测量与预测结果表明:谱聚类与Spearman关联分析可有效降低温度变量共线性导致的耦合作用;MCSO-SVM可实现典型转速下主轴五项热误差的高精度预测,模型具备较好的泛化能力和鲁棒性。 展开更多
关键词 机床 热误差 谱聚类 改进鸡群算法 支持向量机
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