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Application of Hankel Dynamic Mode Decomposition for Wide Area Monitoring of Subsynchronous Resonance

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Energy Engineering 2023年第4期120卷 851-867页

作者： Lei Wang Tiecheng Li Hui Fan Xuekai Hu Lin yang xiaomei yang State Grid Hebei Electric Power Research Institute Shijiazhuang050021China State Grid Hebei Electric Power Company Shijiazhuang050021China The College of Electrical Engineering Sichuan UniversityChengdu610065China

In recent years,subsynchronous resonance(SSR)has frequently occurred in DFIG-connected series-compensated systems.For the analysis and prevention,it is of great importance to achieve wide area monitoring of the incident.This paper presents a Hankel dynamic mode decomposition(DMD)method to identify SSR parameters using synchrophasor data.The basic idea is to employ the DMD technique to explore the subspace of Hankel matrices constructed by synchrophasors.It is analytically demonstrated that the subspace of these Hankel matrices is a combination of fundamental and SSR modes.Therefore,the SSR parameters can be calculated once the modal parameter is extracted.Compared with the existing method,the presented work has better dynamic performances as it requires much less data.Thus,it is more suitable for practical cases in which the SSR characteristics are timevarying.The effectiveness and superiority of the proposed method have been verified by both simulations and field data.

关键词： Hankel dynamic mode decomposition time-varying sub-synchronous oscillation synchrophasor

Mapping China’s offshore mariculture based on dense time-series optical and radar data

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International Journal of Digital Earth 2022年第1期15卷 1326-1349页

作者： Xiaoliang Liu Zhihua Wang xiaomei yang Yueming Liu Bin Liu Junyao Zhang Ku Gao Dan Meng Yaxin Ding State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China

Due to the weak information about cultural targets in the complex marine environment,an omission problem exists in large-scale mariculture extraction using single-view and single-source images.To overcome this problem,we developed a mariculture extraction method that combines dense time-series Sentinel-2 and Sentinel-1 data.A high-precision Chinese mariculture distribution map for 2020 was produced with an overall accuracy of 94.00%and a kappa coefficient of 0.91.The results show that(1)the total area of mariculture was 1173249.22 ha on the national scale,which was significantly larger than the previous studies(459595.70 and 205920.28 ha,respectively),with Shandong Province(39.09%)having the largest proportion;(2)China’s mariculture presented a spatial distribution characteristic of‘Denser North and Sparser South’,and mariculture was centralized in the coastal zones of the northern provinces(60.76%)rather than the southern provinces;(3)the official production statistics and remote sensing-derived mariculture area revealed a highly corresponding trend at the provincial level,with an R2 reaching 0.78,which is much higher than the 0.07 and 0.41 values of the comparison data.The results directly provide data reference for mariculture production estimation and site selection or ideas for mariculture extraction in other regions and globally.

关键词： Aquaculture mariculture multi-source remote sensing time-series China’s coastal zone

结构化最大间隔双支持向量机在股票预测中的应用

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计算机工程与应用 2024年第11期60卷 346-355页

作者：林明松杨晓梅杨志霞新疆大学数学与系统科学学院乌鲁木齐830046

股票价格受政策、宏观经济以及公司经营状况等多方因素的影响,且各因素之间存在较高的相关性,因此股票数据存在的高噪声、非平稳等特性使得股票预测充满困难。为了减少数据中存在的噪声对股价预测准确性的影响,基于马氏距离的类间隔可分... 详细信息

股票价格受政策、宏观经济以及公司经营状况等多方因素的影响,且各因素之间存在较高的相关性,因此股票数据存在的高噪声、非平稳等特性使得股票预测充满困难。为了减少数据中存在的噪声对股价预测准确性的影响,基于马氏距离的类间隔可分性,提出了结构化最大间隔双支持向量机,其分别针对正类样本和负类样本,寻找两个非平行的超平面,使每一类样本离本类样本的欧式距离尽可能小,同时离异类超平面的马氏距离尽可能大。8组基准数据集的实验结果表明,该方法在含噪声数据的分类问题上具有稳定的准确率,从而提升了模型的预测性能和抗噪能力。同时将其应用到股票涨跌趋势预测中,通过对上证综指、上证A指、上证380指数以及中国平安等14只股票实证分析的结果表明,相较于其他对比模型,结构化最大间隔双支持向量机表现出了较好的预测结果,具有一定的实用价值。

关键词：分类问题双支持向量机数据结构马氏距离股票预测

Incorporation of a histone mutant with H3K56 site substitution perturbs the replication machinery in mouse embryonic stem cells

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Journal of Molecular Cell Biology 2022年第3期14卷 23-35页

作者： Xuan Kang xiaomei yang Xiaobo Guo Yabin Li Chenxin yang Huimin Wei Jianfeng Chang Research Center for Translational Medicine East HospitalSchool of Life Sciences and TechnologyTongji UniversityShanghai 200092China Tsingdao Advanced Research Institute Tongji UniversityQingdao 266071China

Sense mutations in several conserved modifiable sites of histone H3 have been found to be strongly correlated with multiple tissuespecific clinical cancers.These clinical site mutants acquire a distinctively new epigenetic role and mediate cancer evolution.In this study,we mimicked histone H3 at the 56th lysine(H3K56)mutant incorporation in mouse embryonic stem cells(mESCs)by lentivirus-mediated ectopic expression and analyzed the effects on replication and epigenetic regulation.The data show that two types of H3K56 mutants,namely H3 lysine 56-to-methionine(H3K56M)and H3 lysine 56-to-alanine(H3K56A),promote replication by recruiting more minichromosome maintenance complex component 3 and checkpoint kinase 1 onto chromatin compared with wild-type histone H3 and other site substitution mutants.Under this condition,the frequency of genomic copy number gain in H3K56M and H3K56A cells globally increases,especially in the Mycl1 region,a known molecular marker frequently occurring in multiple malignant cancers.Additionally,we found the disruption of H3K56 acetylation distribution in the copy-gain regions,which indicates a probable epigenetic mechanism of H3K56M and H3K56A.We then identified that H3K56M and H3K56A can trigger a potential adaptation to transcription;genes involved in the mitogen-activated protein kinase pathway are partially upregulated,whereas genes associated with intrinsic apoptotic function show obvious downregulation.The final outcome of ectopic H3K56M and H3K56A incorporation in mESCs is an enhanced ability to form carcinomas.This work indicates that H3K56 site conservation and proper modification play important roles in harmonizing the function of the replication machinery in mESCs.

关键词： H3K56A/M mutants replication promotion replication stress transcriptional adaptation mouse embryonic stem cells

土壤水分及磷水平对草甘膦农药降解动力学的影响

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土壤学报 2024年第2期61卷 469-483页

作者：丁玲玲薛萐杨晓梅西北农林科技大学资源环境学院陕西杨凌712100 西北农林科技大学水土保持研究所/黄土高原土壤侵蚀与旱地农业国家重点实验室陕西杨凌712100

近年来,草甘膦及其降解产物氨甲基膦酸(AMPA)在土壤中的持久性及其环境风险日益受到关注。然而,草甘膦与磷酸盐结构相似且带电荷,可能与磷酸盐在土壤颗粒表面产生吸附竞争,进而影响其在土壤中的环境行为及土壤磷的生物有效性。本研究通... 详细信息

近年来,草甘膦及其降解产物氨甲基膦酸(AMPA)在土壤中的持久性及其环境风险日益受到关注。然而,草甘膦与磷酸盐结构相似且带电荷,可能与磷酸盐在土壤颗粒表面产生吸附竞争,进而影响其在土壤中的环境行为及土壤磷的生物有效性。本研究通过室内控制试验,对不同磷酸二氢钾施用水平(0,50 mg·kg^(-1),100 mg·kg^(-1))及水分条件下(20%田间持水量(20FC),60%田间持水量(60FC))黄土中草甘膦农药降解动力学、土壤速效磷及土壤酶活性变化特征进行研究。结果表明:(1)不同磷酸二氢钾施用及水分条件下,草甘膦农药在喷施初期降解速率较快,后期逐渐减缓;不同磷酸二氢钾施用水平对草甘膦降解影响不显著,但不同水分梯度对其影响差异显著。其降解产物AMPA的含量随着草甘膦农药的降解而增加,不同磷酸二氢钾施用水平处理AMPA的含量差异不显著,但不同水分条件下其峰值及变化特征差异显著,即:20FC条件下至喷施后第14天达到峰值,而60FC条件下在喷施后第7天就达到峰值。通过拟合发现,草甘膦残留数量特征符合污染物一级动力学衰减模型,其半衰期分别为69.3~77.0 d(20FC)和10.5~12.8 d(60FC)。(2)草甘膦农药喷施后,土壤中速效磷含量随草甘膦农药的降解呈现先减小后增大的变化特征,土壤水分对其影响差异显著。此外,草甘膦农药喷施后,磷酸酶活性受到明显抑制,N-乙酰胺基-β-葡萄糖苷酶、β-葡萄糖苷酶、亮氨酸酶活性波动较大。不同磷酸二氢钾施用水平对以上四种土壤酶活性的影响差异不显著,但不同水分梯度对其影响较大。由此表明:黄土中磷水平对草甘膦农药降解特征的影响不显著,但土壤水分状况显著影响草甘膦农药的衰减速率及其降解产物的残留水平;同时,草甘膦农药喷施,对黄土中速效磷及磷酸酶活性的影响较大,可能对土壤P循环及植物利用产生影响。因此,后续研究还应考虑草甘膦与土壤磷组分及相关酶活性的互馈效应,特别是在干旱条件下草甘膦及其降解产物的持久性与土壤健康的关系研究,以期为黄土区草甘膦农药的安全喷施提供科学依据。

关键词：草甘膦氨甲基膦酸(AMPA) 降解动力学速效磷土壤健康

Qualitative and quantitative assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream by HPLC-TOF-MS and HPLC

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Journal of Pharmaceutical Analysis 2019年第3期9卷 156-162页

作者： Wenling yang xiaomei yang Fanghua Shi Zhigang Liao Yongkun Liang Liangzhong Yu Ruixun Wang Qing Li Kaishun Bi School of Pharmacy Shenyang Pharmaceutical University Shenyang 110016 China G.D China Resources Shunfeng Pharmaceutical Co. Ltd Guangdong 528300 China

Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B′ optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.

关键词： Compound Ketoconazole and Clobetasol Propionate Cream Ketoconazole impurity B' optical isomer Ketoconazole impurity E Quality control HPLC-TOF-MS HPLC

Hydrolysis of cellobiose catalyzed by zeolites—the role of acidity and micropore structure

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Journal of Energy Chemistry 2016年第1期25卷 141-145页

作者： Lipeng Zhou Zhen Liu Yuqi Bai Tianliang Lu xiaomei yang Jie Xu College of Chemistry and Molecular Engineering Zhengzhou University School of Chemical Engineering and Energy Zhengzhou University State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences

The roles of acidity and micropore structure of zeolite were studied in the hydrolysis of the model oligosaccharide of cellulose–cellobiose. HZSM-5, HY, HMOR and Hβ zeolites were selected as model catalysts for the hydrolysis of cellobiose. The effect of acidity of zeolite, including the strength, type and location, on its catalytic activity was investigated. The strong Br？nsted acid sites located in micropores are the active sites for the hydrolysis of cellobiose to glucose. Meanwhile, the catalytic performance of zeolite is also dependent on the micropore size of zeolite.

关键词： Zeolites Biomass Cellulose Hydrolysis Acidity

Synthesis of Mesoporous Anatase TiO2 Sphere with High Surface Area and Enhanced Photocatalytic Activity

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Journal of Materials Science & Technology 2017年第3期33卷 300-304页

作者： Tianliang Lu Youqiang Wang Yingli Wang Lipeng Zhou xiaomei yang Yunlai Su School of Chemical Engineering and Energy Zhengzhou University Zhengzhou 450001 China College of Chemistry and Molecular Engineering Zhengzhou University Zhengzhou 450001 China

Mesoporous anatase TiO2 spheres with high surface area（119 m^2g^（-1）） were successfully synthesized via a facile and green template-free method. The prepared TiO2 was characterized by X-ray diffraction（XRD）,N2 adsorption, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and UV–vis absorbance spectra. It was found that the prepared TiO2 is characterized by pure anatase phase, which shows uniform spheres and has a typical mesostructure with a high specific surface area and a large pore volume. The effects of complexant（acetylacetone） amount, crystallization temperature and calcination temperature were also investigated. Based on the results, a sketch for the preparation of mesoporous TiO2 was proposed. First, complex formed between tetrabutyl titanate and acetylacetone in ethanol. After introduction of aqueous of ammonia sulfate and urea, hydrolysis of tetrabutyl titanate would occur slowly,and sol of TiO2 was formed. Then, crystallization proceeded under hydrothermal conditions. Calcination process favored the formation of bigger TiO2 crystal through combining of the small crystals in TiO2.This led to the formation of bigger mesopores between TiO2 crystals. Photocatalytic activity of the prepared TiO2 was evaluated by decomposition of methyl orange.

关键词： TiO2 Mesoporous Template-free method Photocatalysis

Conversion of syngas to higher alcohols over Cu-Fe-Zr catalysts induced by ethanol

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Journal of Natural Gas Chemistry 2009年第3期18卷 337-340页

作者： Hongtao Zhang xiaomei yang Lipeng Zhou Yunlai Su Zhongmin Liu Department of Chemistry Zhengzhou University Zhengzhou 450052 Henan China Laboratory of Natural Gas Utilization and Applied Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China

Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method, it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol, the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.

关键词： Fe-Cu-Zr catalyst CO hydrogenation higher alcohols induced by ethanol