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计及周期/半周期性边界条件的永磁电机子域模型

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中国电机工程学报 2024年第8期44卷 3287-3296,I0030页

作者：刘辉吴新振陈春涛郑晓钦青岛大学电气工程学院山东省青岛市266071 青岛大学自动化学院山东省青岛市266071

该文提出的表贴磁极永磁电机考虑周期/半周期性边界条件的子域模型,为舰船大容量直驱多相永磁推进电机的设计优化提供一种快速、高效的工具。介绍周期性边界条件和半周期性边界条件的原理及实现方法,并将其应用到基于等效面电流的子域... 详细信息

该文提出的表贴磁极永磁电机考虑周期/半周期性边界条件的子域模型,为舰船大容量直驱多相永磁推进电机的设计优化提供一种快速、高效的工具。介绍周期性边界条件和半周期性边界条件的原理及实现方法,并将其应用到基于等效面电流的子域模型中求解电机气隙磁场,而后通过有限元仿真验证了解析计算的准确性。对比3种求解域下子域模型中谐波系数矩阵的维数和求解速度,表明考虑周期/半周期性边界条件的子域模型在保证结果精度的前提下,能大幅降低矩阵维数,并显著减少求解时间。对实验样机进行空载和负载实验,空载反电势与负载转矩实验结果与解析结果吻合较好,进一步说明了周期/半周期性边界条件下所用子域模型的正确性。

关键词：表贴磁极永磁电机周期性边界条件半周期性边界条件子域法等效面电流

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柔性MXene/壳聚糖/氧化细菌纤维素气凝胶传感器的制备及性能研究

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纤维素科学与技术 2024年第1期32卷 39-48,I0001页

作者：黎永盛陈春涛孙东平南京理工大学江苏南京210094

以氧化细菌纤维素、壳聚糖和MXene为基底材料,通过静电相互作用和京尼平化学交联制备高灵敏、稳定的导电气凝胶。利用SEM观察了气凝胶的微观结构,并通过FT-IR、XPS、XRD等手段表征了气凝胶的化学组成及晶型。最后评价了复合气凝胶的压... 详细信息

以氧化细菌纤维素、壳聚糖和MXene为基底材料,通过静电相互作用和京尼平化学交联制备高灵敏、稳定的导电气凝胶。利用SEM观察了气凝胶的微观结构,并通过FT-IR、XPS、XRD等手段表征了气凝胶的化学组成及晶型。最后评价了复合气凝胶的压敏性能和人体传感应用。结果表明气凝胶具有较低的质量,其密度仅为1.202 g/cm^(3);其能在500 ms内实现对外力/自身形变的响应;在一定外力范围内,其电阻值在8 000~2 000Ω区间内变化;气凝胶对人体运动进行响应的同时还能区别出不同的运动状态。

关键词：细菌纤维素壳聚糖京尼平导电气凝胶传感

Obtaining accurate measurements of the sea surface height from a GPS buoy

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Acta Oceanologica Sinica 2023年第6期42卷 78-88页

作者： Wanlin Zhai Jianhua Zhu chuntao chen Wu Zhou Longhao Yan Yufei Zhang Xiaoqi Huang Kai Guo National Ocean Technology Center Tianjin 300112China School of Ocean Yantai UniversityYantai 266004China National Satellite Ocean Application Service Beijing 100081China

A dedicated GPS buoy is designed for calibration and validation(Cal/Val)of satellite altimeters since *** order to evaluate the accuracy of the sea surface height(SSH)measured by the GPS buoy,twelve campaigns have been done within China sea area between 2014 and *** six of these campaigns,two static Global Navigation Satellite System stations were installed at distances of<1 km and 19 km from the buoy to assess how the baseline length influenced the derived SSH from the buoy *** GPS buoy data was processed using the GAMIT/GLOBK software+TRACK module and CSRS-PPP tool to achieve the *** SSH was compared with conventionally tide gauge(TG)data to evaluate the accuracy of the buoy with the standard deviation of the height *** results showed that the difference in the standard deviation of the SSH from the buoy and the TG was less than 16 *** SSHs processed with different ephemeris(Ultra-Rapid,Rapid,Final)were not significantly *** the baseline length was 19 km,the SSH solution of the GPS buoy performed well,with standard bias of less than 26 mm between the heights measured by the buoy and TG,meaning that the buoy could be used for Cal/Val of *** bias between the Canadian Spatial Reference System-precise point positioning tool and the TRACK varied a lot,and some of them were over 130 *** deemed too high to be useful for Cal/Val of satellite ***,the GPS buoy solutions processed by GAMIT/GLOBK software+TRACK module were used for in-orbit Cal/Val of HY-2B/C satellites in ten *** SSH and significant wave height of the altimeters showed good agreements with the GPS buoy solutions.

关键词： GPS buoy sea surface height baseline length precise point positioning satellite altimeter HY-2

Building a High-Performance Graph Storage on Top of Tree-Structured Key-Value Stores

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Big Data Mining and Analytics 2024年第1期7卷 156-170页

作者： Heng Lin Zhiyong Wang Shipeng Qi Xiaowei Zhu chuntao Hong Wenguang chen Yingwei Luo School of Computer Science Peking UniversityBeijing 100871China Ant Group Beijing 100020China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

Graph databases have gained widespread adoption in various industries and have been utilized in a range of applications,including financial risk assessment,commodity recommendation,and data lineage *** the principles and design of these databases have been the subject of some investigation,there remains a lack of comprehensive examination of aspects such as storage layout,query language,and *** present study focuses on the design and implementation of graph storage layout,with a particular emphasis on tree-structured key-value *** also examine different design choices in the graph storage layer and present our findings through the development of TuGraph,a highly efficient single-machine graph database that significantly outperforms well-known Graph DataBase Management System(GDBMS).Additionally,TuGraph demonstrates superior performance in the Linked Data Benchmark Council(LDBC)Social Network Benchmark(SNB)interactive benchmark.

关键词： graph database high-performance graph storage

Verification and recalibration of HY-2A microwave radiometer brightness temperature

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Journal of Oceanology and Limnology 2019年第3期37卷 968-981页

作者： ZHAO Yili LI Huimin chen chuntao ZHU Jianhua National Ocean Technology Centre Tianjin 300112China Laboratoire d’Oceanographie Physique et Spatiale IfremerPlouzané 29280France

HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM)to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content,and rain *** verified the RM level 1B brightness temperature(T B)to retrieve environmental *** the verification,TB that simulated using the ocean-atmosphere radiative transfer model(RTM)was used as a *** total bias and total standard deviation(SD)of the RM level 1B TB,with reference to the RTM simulation,ranged-20.6-4.38 K and 0.7-2.93 K,*** found that both the total bias and the total SD depend on the frequency and polarization,although the values for ascending and descending passes are *** addition,substantial seasonal variation of the bias was found at all *** verification results indicate the RM has some problems regarding calibration,e.g.,correction of antenna spillover and antenna physical emission,especially for the 18.7-GHz *** on error analyses,a statistical recalibration algorithm was designed and recalibration was performed for the RM level 1B *** of the recalibrated TB indicated that the quality of the recalibrated RM level 1B TB was improved *** bias of the recalibrated T B at all channels was reduced to<0.4 K,seasonal variation was almost eradicated,and SD was diminished(i.e.,the SD of the 18.7-GHz channel was reduced by more than 0.5K).

关键词： HY-2A microwave radiometer brightness temperature(TB) verification calibration

Preliminary calibration results for Jason-3 and Sentinel-3 altimeters in the Wanshan Islands

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Journal of Oceanology and Limnology 2021年第2期39卷 458-471页

作者： Wanlin ZHAI Jianhua ZHU Xiaohui FAN Longhao YAN chuntao chen Zhen TIAN National Ocean Technology Center Tianjin 300112China Tianjin Guohai Marine Engineering Survey Co.Ltd. Tianjin 300000China

We present preliminary calibration results for Jason-3 and Sentinel-3A altimeters that we set up in the Wanshan Islands in Guandong Province,*** campaigns were carried out in 2018,from March 8 to April 16 and from November 3 to December 11,*** GPS reference stations and tide gauges were established on the islands of Zhiwan,Dangan,and Wailingding during the *** in-situ sea surface height(SSH)of the altimeter footprint was determined using the tide *** tidal and geoid connection between the tide gauge locations and the altimeter footprints were computed with the NAO.99Jb tidal prediction system and the EGM 2008 geoid,*** data of the tide gauges were defi ned using the GPS buoy and GPS reference stations during the *** results show that the waveform of the altimeters was slightly contaminated by the small *** bias associated with Jason-3 and Sentinel-3A amounted to approximately+20.7±49.7 mm and+30.1±39.4 mm,respectively,which agreed well with the results from other in-situ calibration fi *** indicates that the Wanshan area was very suitable as an in-situ calibration/validation fi *** wet zenith delay(WZD)determined from the Microwave Radiometer(MWR)and the GPS measurements diff ered from each other for the Jason-3 and Sentinel-3A by−6.6±7.4 mm and 0±6.8 mm,respectively.

关键词： altimeter calibration tide gauge GPS buoy wet zenith delay

An improved method of absolute calibration to satellite altimeter: A case study in the Yellow Sea, China

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Acta Oceanologica Sinica 2014年第5期33卷 103-112页

作者： LIU Yalong TANG Junwu ZHU Jianhua LIN Mingsen ZHAI Wanlin chen chuntao Ocean University of China National Ocean Technological Center State Oceanic Administration National Satellite Ocean Application Service State Oceanic Administration

An improved absolute calibration technology based on indirect measurements was developed through two probative experiments, the performance of which was evaluated by applying the approach to in situ sea surface height （SSH） at the Tianheng Island （tidal gauge） and the satellite nadir （GPS buoy）. Using Geoid/MSS （mean sea surface） data, which accounted for a constant offset between nadir and onshore tidal gauge water levels, and TMD （tidal model driver）, which canceled out the time-varying offsets, nadir SSH （sea surface height） could be indirectly acquired at an onshore tidal gauge instead of from direct offshore observation. The approach extrapolated the onshore SSH out to the offshore nadir with an accuracy of （1.88±0.20） cm and a standard deviation of 3,3 cm, which suggested that the approach presented was feasible in absolute altimeter calibration/validation （Cal/Val）, and the approach enormously facilitated the obtaining SSH from the offshore nadir.

关键词： radar altimeter absolute calibration Yellow Sea

Measurement of the sea surface using a GPS towing-body in Wanshan area

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Acta Oceanologica Sinica 2020年第5期39卷 123-132页

作者： Wanlin Zhai Jianhua Zhu Chaofei Ma Xiaohui Fan Longhao Yan He Wang chuntao chen National Ocean Technology Center Tianjin 300112China National Satellite Ocean Application Service Beijing 100081China Tianjin Guohai Marine Engineering Survey Co.Ltd Tianjin 300350China

Wanshan area has been chosen to be the specified field to calibrate and validate(Cal/Val)the HY-2 altimeter and its follow-on *** March 2018,an experiment has been conducted to determine the sea surface height(SSH)under the HY-2 A ground track(Pass No.203).A GPS towing-body(GPS-TB)was designed to measure the SSH covering an area of about 6 km×28 km wide centered on the HY-2 A altimeter satellite ground *** GPS reference stations,one tide gauge and a GPS buoy were placed in the research area,in order to process and resolve the kinematic solution and check the precision of the GPS-TB *** the GPS data were calculated by the GAMIT/GLOBK software and TRACK *** sea surface was determined by the GPS-TB solution and the tide gauge placed on Zhiwan *** the sea surface of this area was interpolated by Arc GIS10.2 with ordinary Kriging *** results showed that the precision of the GPS-TB is about 1.10 cm compared with the tide gauge placed nearby,which has an equivalent precision with the GPS *** interpolated sea surface has a bias of–1.5–4.0 cm with standard deviation of 0.2–2.4 cm compared with the checking *** gradient of the measured sea surface is about 1.62 cm/km along the HY-2 orbit which shows a good agreement compared with the CLS11 mean sea surface(MSS).In the Cal/Val of satellites,the sea surface between the tide gauge/GPS buoy and the footprint of altimeter can be improved by this work.

关键词： GPS towing-body sea surface height GPS buoy GPS reference station tide gauge sea surface

Absolute calibration of HY-2A and Jason-2 altimeters for sea surface height using GPS buoy in Qinglan, China

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Journal of Oceanology and Limnology 2019年第5期37卷 1533-1541页

作者： chen chuntao ZHU Jianhua ZHAI Wanlin YAN Longhao ZHAO Yili HUANG Xiaoqi YANG Weiwei National Ocean Technology Center Ministry of Natural Resources (MNR)

GPS buoy methodology is one of the main calibration methodologies for altimeter sea surface height calibration. This study introduces the results of the Qinglan calibration campaign for the HY-2A and Jason-2 altimeters. It took place in two time slices;one was from August to September 2014, and the other was in July 2015. One GPS buoy and two GPS reference stations were used in this campaign. The GPS data were processed using the real-time kinematic (RTK) technique. The fi nal error budget estimate when measuring the sea surface height (SSH) with a GPS buoy was better than 3.5 cm. Using the GPS buoy, the altimeter bias estimate was about -2.3 cm for the Jason-2 Geophysical Data Record (GDR) Version ‘D' and from -53.5 cm to -75.6 cm for the HY-2A Interim Geophysical Data Record (IGDR). The bias estimates for Jason-2 GDR-D are similar to the estimates from dedicated calibration sites such as the Harvest Platform, the Crete Site and the Bass Strait site. The bias estimates for HY-2A IGDR agree well with the results from the Crete calibration site. The results for the HY-2A altimeter bias estimated by the GPS buoy were verifi ed by cross-calibration, and they agreed well with the results from the global analysis method.

关键词： HY-2A altimeter calibration GPS buoy sea surface height Jason-2 altimeter