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非饱和粉质黏土中毛细作用对X70钢电化学腐蚀行为的影响

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太原理工大学学报 2024年第5期55卷 865-873页

作者：何斌梁登钦兰茹蒙许俊龙何畅柳堰魏建建太原理工大学土木工程学院太原030024

【目的】探究毛细作用对X70钢在土壤中腐蚀的规律。【方法】基于非饱和土与电化学阻抗谱理论,结合极化曲线技术(PC)、电化学阻抗技术(EIS)、扫描电子显微镜(SEM)等测试方法,在室内条件下通过一维土柱仪的模拟试验研究了粉质黏土中毛细... 详细信息

【目的】探究毛细作用对X70钢在土壤中腐蚀的规律。【方法】基于非饱和土与电化学阻抗谱理论,结合极化曲线技术(PC)、电化学阻抗技术(EIS)、扫描电子显微镜(SEM)等测试方法,在室内条件下通过一维土柱仪的模拟试验研究了粉质黏土中毛细作用对X70钢的电化学腐蚀行为。【结果】试验结果表明,毛细作用对X70钢的电化学腐蚀行为具有一定的影响,即在土柱12 cm、27 cm高度位置处的钢片腐蚀速率随埋置时间先增大后减小,在土柱42 cm、57 cm高度位置处的钢片腐蚀速率随埋置时间先减小后增大;毛细水在粉质黏土中的上升速率满足先快后慢的规律。【结论】X70钢片表面的腐蚀类型以点蚀为主,且腐蚀产物表面伴有较深较宽的裂缝,随着土样高度的增加,腐蚀程度降低,整体上腐蚀坑的大小和数目均呈现出减小趋势;毛细水上升过程中,当X70钢片处于固-液-气三相界面(TPB)时,其腐蚀速率最快,腐蚀程度最严重。

关键词：非饱和粉质黏土 X70钢毛细作用电化学阻抗谱 SEM

不同低温时间无水保活对中国圆田螺存活、营养组成、消化酶活性及抗氧化指标的影响

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水产学报 2024年第6期48卷 194-204页

作者：周康奇韦孜娜李哲林勇黄姻杜雪松覃俊奇陈忠欧红霞徐俊龙项桂德潘贤辉广西壮族自治区水产科学研究院广西水产遗传育种与健康养殖重点实验室广西水产良种海南南繁基地广西钦州农业学校防城港职业技术学院

为改进中国圆田螺保存技术，促进螺蛳粉产业可持续发展。本研究利用初始体重为(21.71±2.70) g的健康中国圆田螺1 500只，探讨了低温(4°C)无水条件下0、14、28、42和56 d等不同时间中国圆田螺存活、形体指标、一般营养组成、脂肪酸、... 详细信息

为改进中国圆田螺保存技术，促进螺蛳粉产业可持续发展。本研究利用初始体重为(21.71±2.70) g的健康中国圆田螺1 500只，探讨了低温(4°C)无水条件下0、14、28、42和56 d等不同时间中国圆田螺存活、形体指标、一般营养组成、脂肪酸、消化酶活性和抗氧化指标的变化。结果显示，4°C短期存放(14～28 d)中国圆田螺的存活率均超过93%，但是超过42 d后，存活率降至78%以下。低温28和42 d的肝重和肝体比均显著高于对照组，与对照组相比，低温56 d体重降了7.6%，而肝重显著提高。营养成分结果显示，各组间肌肉的粗蛋白、粗灰分和水分均无显著影响。而粗脂肪含量呈现上升趋势，其中28、42和56 d的粗脂肪含量显著高于对照组。糖原含量总体呈上升趋势，其中14与56 d差异显著。脂肪酸结果显示，SFA和MUFA含量总体均呈下降趋势，28～56 d均显著低于对照和14 d组；28和42 d的PUFA含量显著高于其他处理组。本研究中所有消化酶和抗氧化酶活性总体均呈现下降趋势。对照组的淀粉酶活性显著低于14 d，但显著高于42 d。除42d的胰蛋白酶外，其余处理的脂肪酶和胰蛋白酶含量显著低于对照组。42 d的谷胱甘肽过氧化氢酶显著低于其他各组，且42 d的超氧化物歧化酶、过氧化氢酶活性和丙二醛含量也均显著低于对照组。研究表明，在4°C条件下无水保活超过42 d会导致中国圆田螺出现较高的死亡率，由于42 d后体内的消化酶和抗氧化酶活性降低，内环境平衡被打破，进而导致高的死亡率。胁迫期间中国圆田螺主要以蛋白质作为能量来源，其次是大量的饱和脂肪酸与单不饱和脂肪酸作为能量物质被消耗，而多不饱和脂肪酸被更好地保留下来。本研究为了解中国圆田螺在低温无水保活不同时间下的生理生化适应对策及改善其储存运输管理提供科学依据。

关键词：中国圆田螺低温时间营养组成脂肪酸酶活性抗氧化指标

Shells in the cabinet:four new species of Tellinidae(Mollusca:Bivalvia:Tellinoidea)identified from existing South China Sea collections

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Journal of Oceanology and Limnology 2024年第2期42卷 627-639页

作者： Yuyan ZHANG junlong ZHANG School of Life Sciences Qingdao Agricultural UniversityQingdao 266109China Laboratory of Marine Organism Taxonomy and Phylogeny Qingdao Key Laboratory of Marine Biodiversity and ConservationInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Marine Biological Museum Chinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

Four species new to science were identified in the Tellinidae museum collections in the Marine Biological Museum of Chinese Academy of *** triquetra ***.,collected in 1981,has not previously been described or *** differs from other Pinguitellina species by its trigonal shape,rose-colored valve interior,and deep and wide pallial sinus,which is confluent with the pallial *** protuberangla *** a broad and deep dorsal corner,short and straight posterodorsal margin,comparatively large adductor scars,depressed and fragile shells,and deep socket at the anterior edge of the right *** minuta *** previously misidentified as Arcopella casta in *** is a new species based on its unique characteristics,which include small,fragile,inflated,translucent,and triangularly ovate-shaped shells with acuminated and convex *** the first species described in China within the genus Abranda Iredale,1924,Abranda xui *** internal ligaments and thin,fragile,and translucent elliptical shells with fine radials on the *** this study,we reorganized the species currently contained in the two genera Pinguitellina and Abranda and created keys to the known *** believe that numerous collected bivalve specimens have been overlooked in the South China Sea,and to date,mollusk has not been adequately ***,further exploration and analysis are required to understand species diversity in this area.

关键词： Abranda morphology Pinguitellina species diversity taxonomy Tellinidae

UAV-Assisted Dynamic Avatar Task Migration for Vehicular Metaverse Services: A Multi-Agent Deep Reinforcement Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 430-445页

作者： Jiawen Kang junlong Chen Minrui xu Zehui Xiong Yutao Jiao Luchao Han Dusit Niyato Yongju Tong Shengli Xie IEEE School of Automation Guangdong University of TechnologyGuangzhou 510006China 111 Center for Intelligent Batch Manufacturing based on IoT Technology Guangzhou 510006China Key Laboratory of Intelligent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China School of Computer Science and Engineering Nanyang Technological UniversitySingaporeSingapore Pillar of Information Systems Technology and Design Singapore University of Technology and DesignSingaporeSingapore College of Communication Engineering Army Engineering University of PLANanjing 210007China National Natural Science Foundation of China Beijing 100085China Key Laboratory of Intelligent Detection and IoT in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong Key Laboratory of IoT Information Technology Guangzhou 510006China

Avatars, as promising digital representations and service assistants of users in Metaverses, can enable drivers and passengers to immerse themselves in 3D virtual services and spaces of UAV-assisted vehicular Metaverses. However, avatar tasks include a multitude of human-to-avatar and avatar-to-avatar interactive applications, e.g., augmented reality navigation,which consumes intensive computing resources. It is inefficient and impractical for vehicles to process avatar tasks locally. Fortunately, migrating avatar tasks to the nearest roadside units(RSU)or unmanned aerial vehicles(UAV) for execution is a promising solution to decrease computation overhead and reduce task processing latency, while the high mobility of vehicles brings challenges for vehicles to independently perform avatar migration decisions depending on current and future vehicle status. To address these challenges, in this paper, we propose a novel avatar task migration system based on multi-agent deep reinforcement learning(MADRL) to execute immersive vehicular avatar tasks dynamically. Specifically, we first formulate the problem of avatar task migration from vehicles to RSUs/UAVs as a partially observable Markov decision process that can be solved by MADRL algorithms. We then design the multi-agent proximal policy optimization(MAPPO) approach as the MADRL algorithm for the avatar task migration problem. To overcome slow convergence resulting from the curse of dimensionality and non-stationary issues caused by shared parameters in MAPPO, we further propose a transformer-based MAPPO approach via sequential decision-making models for the efficient representation of relationships among agents. Finally, to motivate terrestrial or non-terrestrial edge servers(e.g., RSUs or UAVs) to share computation resources and ensure traceability of the sharing records, we apply smart contracts and blockchain technologies to achieve secure sharing management. Numerical results demonstrate that the proposed approach

关键词： Avatar blockchain metaverses multi-agent deep reinforcement learning transformer UAVs

Time-varying parameters estimation with adaptive neural network EKF for missile-dual control system

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Journal of Systems Engineering and Electronics 2024年第2期35卷 451-462页

作者： YUAN Yuqi ZHOU Di LI junlong LOU Chaofei School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Electronic System Engineering Beijing 100854China

In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.

关键词： long-short-term memory(LSTM)neural network extended Kalman filter(EKF) rolling training time-varying parameters estimation missile dual control system

Morphological and molecular analyses of a Philine kinglipini outbreak in summer of 2022 in Jiaozhou Bay,China

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Journal of Oceanology and Limnology 2024年第3期42卷 831-848页

作者： Zelin DUAN Yanan YU Jing WANG junlong ZHANG Nansheng CHEN CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory of Marine Ecology and Environmental Science Laoshan LaboratoryQingdao 266237China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Laboratory of Marine Organism Taxonomy and Phylogeny Qingdao Key Laboratory of Marine Biodiversity and ConservationInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Marine Biological Museum Chinese Academy of SciencesQingdao 266071China Department of Molecular Biology and Biochemistry Simon Fraser UniversityBurnabyBritish ColumbiaV5A 1S6Canada

A sudden and unprecedented outbreak of molluscan Philine kinglipini occurred in summer 2022 in Jiaozhou Bay,Shandong,China,causing substantial damage to local mariculture industry of the Manila clam Ruditapes *** *** has been found in many coastal regions of China,the molecular research of *** has not been extensively studied,making it difficult to accurately identify and track *** samples in field using molecular *** were collected during the outbreak and their morphological features and molecular sequences were *** show that the causative species of the outbreak was *** mitochondrial genome(mt DNA)of *** was constructed for the first time,based on which phylogenetic analysis of the mt DNAs of *** and related species in the order Cephalaspidea was carried *** revealed by metabarcoding analysis of 18S rDNA V4,the seasonal change of *** and closely related Philine species was striking with peaks between April and ***,metabarcoding analysis is applicable tool for monitoring the bloom development of *** and related *** study generated for the first time essential molecular marker sequences and mtDNA of ***,which provided a reference for future characterization and monitoring of its outbreaks and for phylogenetic analysis of Philine species.

关键词： marine species outbreaks metabarcoding analysis mitochondrial genome Philine kinglipini phylogenetics spatial-temporal dynamics

Dimension reduction based on weighted variance estimate

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Science China Mathematics 2009年第3期52卷 539-560页

作者： ZHAO junlong1 & xu XingZhong2 1 Department of Mathematics, Beihang University Laboratory of Mathematics, Information and Behavior of the Ministry of Education, Beijing 100083, China 2 Department of Mathematics, Beijing Institute of Technology, Beijing 100081, China Department of Mathematics Beihang University Laboratory of Mathematics Information and Behavior of the Ministry of Education Beijing China Department of Mathematics Beijing Institute of Technology Beijing China

In this paper, we propose a new estimate for dimension reduction, called the weighted variance estimate (WVE), which includes Sliced Average Variance Estimate (SAVE) as a special case. Bootstrap method is used to select the best estimate from the WVE and to estimate the structure dimension. And this selected best estimate usually performs better than the existing methods such as Sliced Inverse Regression (SIR), SAVE, etc. Many methods such as SIR, SAVE, etc. usually put the same weight on each observation to estimate central subspace (CS). By introducing a weight function, WVE puts different weights on different observations according to distance of observations from CS. The weight function makes WVE have very good performance in general and complicated situations, for example, the distribution of regressor deviating severely from elliptical distribution which is the base of many methods, such as SIR, etc. And compared with many existing methods, WVE is insensitive to the distribution of the regressor. The consistency of the WVE is established. Simulations to compare the performances of WVE with other existing methods confirm the advantage of WVE.

关键词： central subspace contour regression sliced average variance estimate sliced inverse regression sufficient dimension reduction weight function 62G08 62H05

Cellulose sub-nanometric ribbons:A new generation of nanocellulose and platform for biomaterials

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Journal of Bioresources and Bioproducts 2024年第1期9卷 1-2页

作者： Shaomin Kang Yang Zhao junlong Song Huining Xiao Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources and International Innovation Center for Forest Chemicals and Materials Nanjing Forestry UniversityNanjing 210037China Department of Chemical Engineering University of New BrunswickFredericton NB E3B 5A3Canada

With the tremendous progress of research in nanoscience,much attention has been paid to the bottom of the“nano world”:scales around one nanometer or even *** order to describe materials at this scale,a new concept c... 详细信息

关键词： biomaterials scales emerged

A generalized nonlinear three-dimensional Hoek‒Brown failure criterion

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3149-3164页

作者： Jiaxin Wang Shunchuan Wu Haiyong Cheng junlong Sun Xiaolong Wang Yaxi Shen Faculty of Land Resource Engineering Kunming University of Science and TechnologyKunming650093China Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area Ministry of Natural ResourcesKunming650093China Yunnan Key Laboratory of Geohazard Forecast and Geoecological Restoration in Plateau Mountainous Area Kunming650093China

To understand the strengths of rocks under complex stress states,a generalized nonlinear threedimensional(3D)Hoek‒Brown failure(NGHB)criterion was proposed in this *** criterion shares the same parameters with the generalized HB(GHB)criterion and inherits the parameter advantages of *** new parameters,b,and n,were introduced into the NGHB criterion that primarily controls the deviatoric plane shape of the NGHB criterion under triaxial tension and compression,*** NGHB criterion can consider the influence of intermediate principal stress(IPS),where the deviatoric plane shape satisfies the smoothness requirements,while the HB criterion *** criterion can degenerate into the two modified 3D HB criteria,the Priest criterion under triaxial compression condition and the HB criterion under triaxial compression and tension *** criterion was verified using true triaxial test data for different parameters,six types of rocks,and two kinds of in situ rock *** comparison,three existing 3D HB criteria were selected for performance comparison *** result showed that the NGHB criterion gave better prediction performance than other *** prediction errors of the strength of six types of rocks and two kinds of in situ rock masses were in the range of 2.0724%-3.5091%and 1.0144%-3.2321%,*** proposed criterion lays a preliminary theoretical foundation for prediction of engineering rock mass strength under complex in situ stress conditions.

关键词： Rock mechanics HoekeBrown criterion Failure criterion Intermediate principal stress True triaxial test Smoothness and convexity