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Experimental Study on Mixed-Mode(Ⅰ–Ⅱ)Fracture Toughness of Freshwater Ice

Acta Mechanica Solida Sinica 2024年第2期37卷 252-264页

作者： Yaozhong Xu Mao Zhou Xian Yi Wen Hua Jiuzhou Huang wenyu zhang Shiming Dong Key Laboratory of Deep Underground Science and Engineering Ministry of EducationCollege of Architecture and EnvironmentSichuan UniversityChengdu610065China Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province Sichuan UniversityChengdu610065China China Aerodynamics Research and Development Center/Low Speed Aerodynamics Research Institute Mianyang621000China College of Mechanical and Electrical Engineering Xichang UniversityXichang615000China

Ⅰn recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice are unclear and cannot meet the engineering needs of ice-shedding hazard assessment.Therefore,studying the fracture toughness of ice bodies has extremely important practical significance.To address this issue,this article uses a centrally cracked Brazilian disk(CCBD)specimen to measure the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice at different loading rates.The mixed-mode(Ⅰ–Ⅱ)fracture characteristics of ice are discussed,and the experimental results are compared and analyzed with the theoretical values of the generalized maximum tangential stress(GMTS)criterion considering the influence of T-stress.The results indicated that as the loading rate increases,the pure mode Ⅰ toughness and pure mode Ⅱ fracture toughness of freshwater ice decrease,and the fracture toughness of freshwater ice is more sensitive to the loading rate.Ⅰn terms of fracture criteria,the theoretical value of the ratio of pure mode Ⅱ fracture toughness to pure mode Ⅰ fracture toughness based on the GMTS criterion is in good agreement with the experimental value,while the theoretical value based on the maximum tangential stress(MTS)criterion deviates significantly from the experimental value,indicating that the GMTS criterion considering the influence of T-stress can better predict the experimental results.

关键词： Freshwater ice Fracture criteria Centrally cracked Brazilian disk(CCBD) Mixed-mode(Ⅰ-Ⅱ) Loading rate

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Printed circuit board solder joint quality inspection based on lightweight classification network

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IET Cyber-Systems and Robotics 2023年第4期5卷 27-39页

作者： Zhicong zhang wenyu zhang Donglin Zhu Yi Xu Changjun Zhou College of Science Dalian Minzu UniversityDalianChina Department of Information Science and Engineering Ocean University of ChinaQingdaoChina College of Mathematics and Computer Science Zhejiang Normal UniversityJinhuaChina

Solder joint quality inspection is a crucial step in the qualification inspection of printed circuit board(PCB)components,and efficient and accurate inspection methods will greatly improve its production efficiency.In this paper,we propose a PCB solder joint quality detection algorithm based on a lightweight classification network.First,the Select Joint segmentation method was used to obtain the solder joint information,and colour space conversion was used to locate the solder joint.The mask method,contour detection,and box line method were combined to complete the extraction of solder joint information.Then,by combining the respective characteristics of convolutional neural network and Transformer and introducing Cross-covariance attention to reduce the computational complexity and resource consumption of the model and evenly distribute the global view mutual information in the whole training process,a new lightweight network model MobileXT is proposed to complete defect classification.Only 16.4%of the Vision Transformer computing resources used in this model can achieve an average accuracy improvement of 31%.Additionally,the network is trained and validated using a dataset of 1804 solder joint images constructed from 93 PCB images and two external datasets to evaluate MobileXT performance.The proposed method achieves more effi-cient localization of the solder joint information and more accurate classification of weld joint defects,and the lightweight model design is more appropriate for industrial edge device deployments.

关键词： convolutional neural network deep learning neural network-based

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Investigation of carbonyl amidation and O-methylation during biosynthesis of the pharmacophore pyridyl of antitumor piericidins

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Synthetic and Systems Biotechnology 2022年第3期7卷 880-886页

作者： Wanlu Li wenyu zhang Yijia Cheng Yaoyao Shen Jianzhao Qi Hou-Wen Lin Yongjun Zhou Research Center for Marine Drugs State Key Laboratory of Oncogenes and Related GenesDepartment of PharmacyRen Ji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200127China Shaanxi Key Laboratory of Natural Products&Chemical Biology College of Chemistry&PharmacyNorthwest A&F UniversityYangling712100ShaanxiChina

Piericidins are a large family of bacterialα-pyridone antibiotics with antitumor activities such as their anti-renal carcinoma activity exhibited recently in nude mice.The backbones of piericidins are derived fromβ,δ-diketo carboxylic acids,which are offloaded from a modular polyketide synthase(PKS)and putatively undergo a carbonyl amidation beforeα-pyridone ring formation.The tailoring modifications to theα-pyridone structure mainly include the verified hydroxylation and O-methylation of the C-4′position and an unidentified C-5′O-methylation.Here,we describe a piericidin producer,terrestrial Streptomyces conglobatus,which contains a piericidin biosynthetic gene cluster in two different loci.Deletion of the amidotransferase gene pieD resulted in the accumulation of two fatty acids that should be degraded from the nascent carboxylic acid released by the PKS,supporting the carbonyl amidation function of PieD duringα-pyridone ring formation.Deletion of the O-methyltransferase gene pieB1 led to the production of three piericidin analogues lacking C-5′O-methylation,therefore confirming that PieB1 specifically catalyses the tailoring modification.Moreover,bioactivity analysis of the mutant-derived products provided clues regarding the structure-function relationship for antitumor activity.The work addresses two previously unidentified steps involved in pyridyl pharmacophore formation during piericidin biosynthesis,facilitating the rational bioengineering of the biosynthetic pathway towards valuable antitumor agents.

关键词： Polyketide Pyridine Polyketide synthase(PKS) Natural product biosynthesis

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Satellite Navigation Method Based on High-Speed Frequency Hopping Signal

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China Communications 2023年第7期20卷 321-337页

作者： En Yuan Peng Liu Weiwei Chen Rui Wang Bing Xu wenyu zhang Yanqin Tang Command&Control Engineering College Army Engineering University of PLANanjing 210007China

Global navigation satellite system has been widely used,but it is vulnerable to jamming.In military satellite communications,frequency hopping(FH)signal is usually used for anti-jamming communications.If the FH signal can be used in satellite navigation,the anti-jamming ability of satellite navigation can be improved.Although a recently proposed timefrequency matrix ranging method(TFMR)can use FH signals to realize pseudorange measurement,it cannot transmit navigation messages using the ranging signal which is crucial for satellite navigation.In this article,we propose dual-tone binary frequency shift keyingbased TFMR(DBFSK-TFMR).DBFSK-TFMR designs an extended time-frequency matrix(ETFM)and its generation algorithm,which can use the frequency differences in different dual-tone signals in ETFM to modulate data and eliminate the negative impact of data modulation on pseudorange measurement.Using ETFM,DBFSK-TFMR not only realizes the navigation message transmission but also ensures the precision and unambiguous measurement range of pseudorange measurement.DBFSK-TFMR can be used as an integrated solution for anti-jamming communication and navigation based on FH signals.Simulation results show that DBFSK-TFMR has almost the same ranging performance as TFMR.

关键词： satellite navigation frequency hopping ranging navigation message transmission

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Biosynthesis of trialkyl-substituted aromatic polyketide NFAT-133 involves unusual P450 monooxygenase-mediating aromatization and a putative metallo-beta-lactamase fold hydrolase

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Synthetic and Systems Biotechnology 2023年第3期8卷 349-356页

作者： Ming Yang Wanlu Li Lin Zhou Xiao Lin wenyu zhang Yaoyao Shen Hai Deng Hou-wen Lin Yongjun Zhou Research Center for Marine Drugs Department of PharmacyRen Ji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200127China Institute of Marine Drugs Guangxi Key Laboratory of Marine DrugsGuangxi University of Chinese MedicineNanning530200PR China Department of Chemistry University of AberdeenAberdeenAB243UEUK

The bacterial trialkyl-substituted aromatic polyketides are structurally featured with the unusual aromatic core in the middle of polyketide chain such as TM-123(1),veramycin A(2),NFAT-133(3)and benwamycin I(4),which were discovered from Streptomyces species and demonstrated with antidiabetic and immunosuppressant activities.Though the biosynthetic pathway of 1-3 was reported as a type I polyketide synthase(PKS),the PKS assembly line was interpreted inconsistently,and it remains a mystery how the compound 3 was generated.Herein,the PKS assembly logic of 1-4 was revised by site-mutagenetic analysis of the PKS dehydratase domains.Based on gene deletion and complementation,the putative P450 monooxygenase nftE1 and metallo-beta-lactamase(MBL)fold hydrolase nftF1 were verified as essential genes for the biosynthesis of 1-4.The absence of nftE1 led to abolishment of 1-4 and accumulation of new products(5-8).Structural elucidation reveals 5-8 as the non-aromatic analogs of 1,suggesting the NftE1-catalyzed aromatic core formation.Deletion of nftF1 resulted in disappearance of 3 and 4 with the compounds 1 and 2 unaffected.As a rare MBL-fold hydrolase from type I PKSs,NftF1 potentially generates the compound 3 through two strategies:catalyze premature chain-offloading as a trans-acting thioesterase or hydrolyze the lactone-bond of compound 1 as an esterase.

关键词： Thioesterase Metallo hydrolase Metallo-beta-lactamase Aromatic polyketide Polyketide synthase P450 monooxygenase

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Long-term winter observation of nitrous acid in the urban area of Beijing

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Journal of Environmental Sciences 2022年第4期34卷 334-342页

作者： Chaofan Lian Weigang Wang Yan Chen Yusheng zhang Jingwei zhang Yongchun Liu Xiaolong Fan Chang Li Junlei Zhan Zhuohui Lin Chenjie Hua wenyu zhang Mingyuan Liu Junling Li Xuefei Wang Junling An Maofa Ge State Key Laboratory for Structural Chemistry of Unstable and Stable Species CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of the Chinese Academy of Sciences Beijing 100049China Aerosol and Haze Laboratory Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing100029China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC) Institute of Atmospheric Physics(IAP)Chinese Academy of SciencesBeijing 100029China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Center for Excellence in Urban Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

The particulate matter(PM)pollution has been significantly improved by carrying out various valid emission control strategies since 2013 in China.Meanwhile the variation trend of nitrous acid(HONO)is worthy to investigate due to its vital role in the atmospheric oxidation process.In this study,field observation in the winter is conducted to investigate the concentration of HONO in an urban area of Beijing.In the winter of 2019,the mean HONO concentration is 1.38 ppbV during the whole winter.Photo-enhanced NO_(2)heterogeneous reactions on the ground and aerosol surfaces were found as the possible daytime sources of HONO.Compared to O_(3),photolysis of HONO dominates the primary OH sources during the winter time.To understand the HONO pollution patterns by years variation,multi-year data is summarized and finds that primary pollutants including CO and NO decreased,but secondary pollutants i.e.,HONO(mostly generated via secondary process)increased.Our study highlights the requirement to mitigate secondary pollution by control HONO concentration.

关键词： Nitrous acid Field observation Winter air pollution

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基于相变技术的便携式储冷箱性能研究

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制冷学报 2024年第1期45卷 145-157页

作者：张文宇赵长颖上海交通大学工程热物理研究所上海200240

在冷链运输末端温度失效问题普遍存在,本文基于相变技术设计了适用于-18℃以下的冷链末端运输的冷能储存箱。研究了储冷箱在环境温度、真空板厚度、相变材料的种类及其与真空板相对位置等参数变量影响下箱体的温度场特性和储冷性能,并... 详细信息

在冷链运输末端温度失效问题普遍存在,本文基于相变技术设计了适用于-18℃以下的冷链末端运输的冷能储存箱。研究了储冷箱在环境温度、真空板厚度、相变材料的种类及其与真空板相对位置等参数变量影响下箱体的温度场特性和储冷性能,并对不同位置相变材料板单独存在时的储冷性能进行分析。结果表明:储冷箱有良好的抵抗外界温度变化的能力,且装配真空板时最大有效保冷时间延长至29.26 h,相变材料布置在真空板内侧时有效保冷时间延长54.3%。基于实际应用温度所研究的4种相变材料中,相变温度为-21.55℃的2-辛酮储冷性能最佳。对不同位置的相变材料板单独分析发现,底部板对储冷箱整体的储冷效果贡献最大,其单板保冷系数为0.454。

关键词：冷藏单元蓄冷相变材料性能系数

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习近平关于农业现代化的重要论述及其重大价值

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农业经济与管理 2024年第2期 1-12页

作者：张远新张文羽上海交通大学马克思主义学院上海200240

农业现代化是中国式现代化的应有之义和重点难点。新时代以来,习近平统筹实现中华民族伟大复兴战略全局和应对世界百年未有之大变局,着眼于建设社会主义现代化农业强国,坚持新发展理念,坚持问题导向,对我国农业现代化作出了一系列重要... 详细信息

农业现代化是中国式现代化的应有之义和重点难点。新时代以来,习近平统筹实现中华民族伟大复兴战略全局和应对世界百年未有之大变局,着眼于建设社会主义现代化农业强国,坚持新发展理念,坚持问题导向,对我国农业现代化作出了一系列重要论述。主要包括:以战略思维审视农业现代化的时代价值;以系统思维概括农业现代化的中国特色;以创新思维谋划农业现代化的实现途径。这些重要论述不仅丰富拓展了经典马克思主义的农业理论,创新发展了中国共产党的农业现代化思想,同时也为推进中国式农业现代化建设提供了行动指南,为发展中国家农业发展贡献了中国智慧。

关键词：习近平农业现代化重要论述重大价值

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Origination and evolution of orphan genes and de novo genes in the genome of Caenorhabditis elegans

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Science China(Life Sciences) 2019年第4期62卷 579-593页

作者： wenyu zhang Yuanxiao Gao Manyuan Long Bairong Shen Institutes for Systems Genetics West China Hospital Sichuan University Department of Ecology and Evolution the University of Chicago Department of Evolutionary Genetics Max-Planck Institute for Evolutionary Biology Department of Evolutionary Theory Max-Planck Institute for Evolutionary Biology Committee on Genetics the University of Chicago

Orphan genes that lack detectable homologues in other lineages could contribute to a variety of biological functions. However,their origination and function mechanisms remain largely unknown. Herein, through a comprehensive and systematic computational pipeline, we identified 893 orphan genes in the lineage of C. elegans, of which only a low fraction(0.9%) were derived from transposon elements. Six new protein-coding genes that de novo originated from non-coding DNA sequences in the genome of C. elegans were also identified. The authenticity and functionality of these orphan genes and de novo genes are supported by three lines of evidences, consisting of transcriptional data, and in silico proteomic data, and the fixation status data in wild populations. Orphan genes and de novo genes exhibited simple gene structures, such as, short in protein length, of fewer exons,and are frequently X-linked. RNA-seq data analysis showed these orphan genes are enriched with expression in embryo development and gonad, and their potential function in early development was further supported by gene ontology enrichment analysis results. Meanwhile, de novo genes were found to be with significant expression in gonad, and functional enrichment analysis of the co-expression genes of these de novo genes suggested they may be functionally involved in signaling transduction pathway and metabolism process. Our results presented the first systematic evidence on the evolution of orphan genes and de novo origin of genes in nematodes and their impacts on the functional and phenotypic evolution, and thus could shed new light on our appreciation of the importance of these new genes.

关键词： Caenorhabditis elegans,orphan genes de novo genes

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Ultra-High Mass-Loading Cathode for Aqueous Zinc-Ion Battery Based on Graphene-Wrapped Aluminum Vanadate Nanobelts

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Nano-Micro Letters 2019年第4期11卷 215-226页

作者： wenyu zhang Shuquan Liang Guozhao Fang Yongqiang Yang Jiang Zhou School of Materials Science and Engineering Central South UniversityChangsha 410083HunanPeople’s Republic of China Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province Central South UniversityChangsha 410083HunanPeople’s Republic of China

Rechargeable aqueous zinc-ion batteries(AZIBs)have their unique advantages of cost efficiency,high safety,and environmental friendliness.However,challenges facing the cathode materials include whether they can remain chemically stable in aqueous electrolyte and provide a robust structure for the storage of Zn2+.Here,we report on H11Al2V6O23.2@graphene(HAVO@G)with exceptionally large layer spacing of(001)plane(13.36?).The graphene-wrapped structure can keep the structure stable during discharge/charge process,thereby promoting the inhibition of the dissolution of elements in the aqueous electrolyte.While used as cathode for AZIBs,HAVO@G electrode delivers ideal rate performance(reversible capacity of 305.4,276.6,230.0,201.7,180.6 mAh g?1 at current densities between 1 and 10 A g?1).Remarkably,the electrode exhibits excellent and stable cycling stability even at a high loading mass of^15.7 mg cm?2,with an ideal reversible capacity of 131.7 mAh g?1 after 400 cycles at 2 A g?1.

关键词： Aluminum vanadate Graphene Cathode High mass loading Aqueous zinc-ion battery

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