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A Temporal Convolutional Network Based Hybrid Model for Short-term Electricity Price Forecasting

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1119-1130页

作者： Haoran Zhang Weihao Hu Di cao qi Huang Zhe Chen Frede Blaabjerg School of Mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengduChina Department of Energy Technology Aalborg UniversityAalborgDenmark IEEE

Electricity prices have complex features,such as high frequency,multiple seasonality,and nonlinearity.These factors will make the prediction of electricity prices difficult.However,accurate electricity price prediction is important for energy producers and consumers to develop bidding strategies.To improve the accuracy of prediction by using each algorithms’advantages,this paper proposes a hybrid model that uses the Empirical Mode Decomposition(EMD),Autoregressive Integrated Moving Average(ARIMA),and Temporal Convolutional Network(TCN).EMD is used to decompose the electricity prices into low and high frequency components.Low frequency components are forecasted by the ARIMA model and the high frequency series are predicted by the TCN model.Experimental results using the realistic electricity price data from Pennsylvania-New Jersey-Maryland(PJM)electricity markets show that the proposed method has a higher prediction accuracy than other single methods and hybrid methods.

关键词： Autoregressive integrated moving average model electricity price forecasting empirical mode decomposition temporal convolutional network

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仿生学锯齿桨叶降噪效果试验研究

航空科学技术 2024年第5期35卷 125-130页

作者：卫凯曹琦燕群陈永辉薛东文陈伟杰中国飞机强度研究所航空声学与振动航空科技重点实验室陕西西安710065 中国飞机强度研究所强度与结构完整性全国重点实验室陕西西安710065 西北工业大学陕西西安710072

以仿生学结构改善发动机的气动性能和噪声水平是当前绿色航空的研究热点,对控制对转螺旋桨的气动噪声具有重要的工程应用价值。本文通过地面声学环境下的气动噪声试验研究了仿生学锯齿结构对转螺旋桨的降噪特性,并测试了锯齿结构桨叶和... 详细信息

以仿生学结构改善发动机的气动性能和噪声水平是当前绿色航空的研究热点,对控制对转螺旋桨的气动噪声具有重要的工程应用价值。本文通过地面声学环境下的气动噪声试验研究了仿生学锯齿结构对转螺旋桨的降噪特性,并测试了锯齿结构桨叶和基准桨的拉力、扭矩等气动性能和远场噪声指向性。试验结果表明,所设计的锯齿结构没有引起基准桨的气动性能损失,可以在保持气动性能的同时开展降噪设计。锯齿结构在4000~12000Hz频率区间,没有改变基准桨叶的噪声指向性特征,最大降噪量超过5dB;在所测转速工况的一阶通过频率、二阶通过频率处没有明显的降噪效果。这进一步说明锯齿结构对宽频噪声有降噪效果,对低频段的离散噪声降噪效果不明显。

关键词：仿生学锯齿结构对转螺旋桨气动噪声试验测试

Hemin-functionalized polypyrrole/paper-derived biochar electrocatalysts:Enhanced sensor platforms for H2O2

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Progress in Natural Science:Materials International 2024年第2期34卷 280-289页

作者： Yuhang Jiang Tianshuang Bao Xiangchuan Zhao qi Wang Yue cao Jun cao Xingxiang Ji Weimeng Si School of Materials Science and Engineering Shandong University of Technology State Key Laboratory of Biobased Material and Green Papermaking Qilu University of Technology (Shandong Academy of Sciences)

As a H2O2electrochemical biomimetic enzyme sensor,the stability,repeatability and sensitivity of hemin-based composites are closely connected with the loading of hemin on high-performance matrix.Herein,polypyrrole/paper-derived carbon（PPy/PC） nanocomposite was used for the construction of a hemin-based non-enzymatic sensor to detect H2O2.Where the poplar wood is used to obtain crude cellulose through a straightforward papermaking process.This crude cellulose is then subjected to pyrolysis to yield the desired paper-based carbon material.The hemin-decorated PPy/PC was demonstrated possessing remarkable electrocatalytic activity for H2O2reduction,and the possible mechanism of the reactions was discussed.The electrochemical sensor,utilizing the HPPy/PC composite,achieved a low detection limit of 30 nM,along with enhanced selectivity and stability under optimized conditions.The favorable results observed can primarily be attributed to the superior electrochemical performance of PPy/PC,as well as its unique 3D interconnected structure.This structure effectively impedes the self-dimerization of hemin,thereby ensuring the generation of active catalytic species.

关键词： Biochar H2O2 sensing Hemin Paper-based carbon materials Paper-making process

Feasibility of same-day discharge following endoscopic submucosal dissection for esophageal or gastric early cancer

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World Journal of Gastroenterology 2022年第41期28卷 5957-5967页

作者： Jing Wang Shi-Jie Li Yan Yan Peng Yuan Wei-Feng Li Chang-qi cao Wei-Gang Chen Ke-Neng Chen qiWu Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education) Endoscopy CenterPeking University Cancer Hospital&InstituteBeijing 100142China The First Affiliated Hospital School of MedicineShihezi UniversityShihezi 832008Xinjiang Uygur Autonomous RegionChina The First Department of Thoracic Surgery Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education)Peking University Cancer Hospital&InstituteBeijing 100142China

BACKGROUND Endoscopic submucosal dissection(ESD)is an established technique for the treatment of early gastrointestinal neoplasia.Generally,multi-day(M-D)admission is required for patients undergoing ESD due to potential complications.AIM To evaluate the feasibility of a same-day(S-D)discharge strategy for ESD of the esophagus or stomach.METHODS The data of patients who underwent esophageal or gastric ESD were retrospectively collected from January 2018 to December 2021 at Peking University Cancer Hospital.The propensity score matching(PSM)method was applied to balance the unevenly distributed patient baseline characteristics between the S-D and M-D groups.Intraoperative and postoperative parameters were compared between the matched groups.RESULTS Among the 479 patients reviewed,470 patients,including 91 in the S-D group and 379 in the M-D group,fulfilled the inclusion and exclusion criteria.Following PSM,78 patients in each group were paired using the 1:1 nearest available score match algorithm.No significant difference was found between groups with respect to intraoperative and postprocedural major adverse events(AEs).Tumor size,complete resection rate,and procedural duration were comparable between the groups.The S-D group demonstrated a significantly shorter length of hospital stay(P<0.001)and lower overall medical expenses(P<0.001)compared with the M-D group.CONCLUSION The S-D discharge strategy may be feasible and effective for esophagogastric ESD,and the procedural-related AEs can be managed successfully.

关键词： Endoscopic submucosal dissection Early esophageal cancer Early gastric cancer Same-day surgery Adverse event

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大采高采煤工作面架空辅助运输装备设计

煤矿机械 2024年第6期45卷 13-16页

作者：陈加胜王梦丽杨帅李庆雨钱怡曹琦安徽理工大学机械工程学院安徽淮南232001

目前,采煤工作面需要的设备材料从两巷到工作面的运输一般有刮板输送机运输或人工搬运2种方法。刮板输送机运输设备材料会影响采煤作业,而且如果设备材料的尺寸过大,采煤机和刮板输送机之间的过煤空间不足、难以通过;人工搬运劳动强度... 详细信息

目前,采煤工作面需要的设备材料从两巷到工作面的运输一般有刮板输送机运输或人工搬运2种方法。刮板输送机运输设备材料会影响采煤作业,而且如果设备材料的尺寸过大,采煤机和刮板输送机之间的过煤空间不足、难以通过;人工搬运劳动强度大、施工速度慢,且在运输过程中容易造成人身安全事故。由于大采高工作面的高度适合安装架空索道,所以设计了一种大采高采煤工作面的架空辅助运输装备,并对索道辅助运输装置进行了受力分析和计算。

关键词：一次采全高运输效率架空辅助运输架空索道

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某水电站调速器压油罐测压组件优化改造

水电站机电技术 2024年第7期47卷 106-107,131页

作者：闫志飞刘警安曹家起杨德志黄帅超雅砻江流域水电开发有限公司四川成都610051

某水电站调速器压油罐压力开关、压力传感器、压力表支架通过法兰直接与压油罐连接,各“元件”通过JJM8-160型号压力表阀与支架连接,其安装位置较高,不便于拆装、观察,且近几年出现重复性漏油缺陷,通过整体换型改造,较好的解决了相关问题。

关键词：调速器压油罐测压组件漏油改造

Electricity Theft Detection Method Based on Ensemble Learning and Prototype Learning

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 213-224页

作者： Xinwu Sun Jiaxiang Hu Zhenyuan Zhang Di cao qi Huang Zhe Chen Weihao Hu the School of Mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengduChina Southwest University of Science and TechnologyChengduChina

With the development of advanced metering infrastructure(AMI),large amounts of electricity consumption data can be collected for electricity theft detection.However,the imbalance of electricity consumption data is violent,which makes the training of detection model challenging.In this case,this paper proposes an electricity theft detection method based on ensemble learning and prototype learning,which has great performance on imbalanced dataset and abnormal data with different abnormal level.In this paper,convolutional neural network(CNN)and long short-term memory(LSTM)are employed to obtain abstract feature from electricity consumption data.After calculating the means of the abstract feature,the prototype per class is obtained,which is used to predict the labels of unknown samples.In the meanwhile,through training the network by different balanced subsets of training set,the prototype is representative.Compared with some mainstream methods including CNN,random forest(RF)and so on,the proposed method has been proved to effectively deal with the electricity theft detection when abnormal data only account for 2.5%and 1.25%of normal data.The results show that the proposed method outperforms other state-of-the-art methods.

关键词： Electricity theft detection ensemble learning prototype learning imbalanced dataset deep learning abnormal level

A review of in situ carbon mineralization in basalt

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1467-1485页

作者： Xiaomin cao qi Li Liang Xu Yongsheng Tan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

Global warming has greatly threatened the human living environment and carbon capture and storage(CCS)technology is recognized as a promising way to reduce carbon emissions.Mineral storage is considered a reliable option for long-term carbon storage.Basalt rich in alkaline earth elements facilitates rapid and permanent CO_(2) fixation as carbonates.However,the complex CO_(2)-fluid-basalt interaction poses challenges for assessing carbon storage potential.Under different reaction conditions,the carbonation products and carbonation rates vary.Carbon mineralization reactions also induce petrophysical and mechanical responses,which have potential risks for the long-term injectivity and the carbon storage safety in basalt reservoirs.In this paper,recent advances in carbon mineralization storage in basalt based on laboratory research are comprehensively reviewed.The assessment methods for carbon storage potential are introduced and the carbon trapping mechanisms are investigated with the identification of the controlling factors.Changes in pore structure,permeability and mechanical properties in both static reactions and reactive percolation experiments are also discussed.This study could provide insight into challenges as well as perspectives for future research.

关键词： Carbon mineralization Basalt CO_(2)-fluid-basalt interaction Petrophysical evolution Mechanical response Carbon capture and storage(CCS)

The theory of early nonlinear stage of m=1 instability with locally flattened q-profile

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Matter and Radiation at Extremes 2018年第5期3卷 243-247页

作者： Kai-qi cao Xian-Qu Wang Institute of Fusion Science School of Physical Science and TechnologySouthwest Jiaotong UniversityChengduSichuan 610031China

In this paper,we analyze the modification of fast particles on the nonlinear radial displacement of m=1 internal kink mode with a shoulderlike equilibrium current theoretically.Using the matching method on the solutions of the outer and inner regions,we derive the analytical form of nonlinear radial displacement in the limit of q'=q"=0,which is valid to the cases of weak shear due to a slight flattening of the q(r)profile around q=1.We have taken into consideration the effects of the circulating and trapped fast particles on the nonlinear state of the mode.It is found that a fast particle can modify the nonlinear saturation level by the change of potential energy,depending on the fast particle properties.By the matching of linear dispersion relation to early nonlinear result,we also obtain the relations of radial displacement to the mode frequency and linear growth rate,and discuss the scaling for different stabilities of the MHD modes.

关键词： Tokamak Magnetohydrodynamics Weak magnetic shear Internal kink mode Fast particle