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Chinese Chemical Letters 2024年第8期35卷 254-259页

作者： Pengfei Zhang Qingxue ma Zhiwei jiang Xiaohua Xu Zhong Jin College of Chemistry State Key Laboratory of Elemento-organic ChemistryNankai UniversityTianjin 300071China Key Laboratory of Xinjiang Native Medicinal and Edible Plant Resource Chemistry College of Chemistry and Environmental SciencesKashi UniversityKashgar 844007China

Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ***,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta ***,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium *** meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.

关键词： C-H functionalization Aryl sulfonic acid Site-selectivity Transition-metal catalysis Alkylation Alkynylation

基于卷积神经网络与约束概率矩阵分解的推荐算法

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计算机科学 2020年第S1期47卷 540-545页

作者：马海江华侨大学计算机科学与技术学院厦门361021

用户评分数据的稀疏性和上下文的信息缺失,往往导致基于矩阵分解(matrix Factorization,MF)的推荐算法在准确性方面有所欠缺。针对此问题,文中提出了一种基于卷积神经网络(Convolutional Neural Networks,CNN)与约束概率矩阵分解(Constr... 详细信息

用户评分数据的稀疏性和上下文的信息缺失,往往导致基于矩阵分解(matrix Factorization,MF)的推荐算法在准确性方面有所欠缺。针对此问题,文中提出了一种基于卷积神经网络(Convolutional Neural Networks,CNN)与约束概率矩阵分解(Constrained Probabilistic matrix Factorization,CPMF)的推荐算法。首先,构建卷积神经网络模型,对用户上下文辅助信息进行识别,获得文本潜在向量,并叠加高斯噪声,初始化项目特征矩阵;然后,根据用户评分信息,利用约束矩阵来约束用户特征,并叠加补偿矩阵,初始化用户特征矩阵;接着,利用初始化的用户特征矩阵和项目特征矩阵拟合评分矩阵,对评分矩阵进行矩阵分解,并利用坐标下降算法更新参数;最后,预测用户对项目的评分,实现项目推荐。在Movielens和Amazon数据集上的实验结果表明,该推荐算法显著优于传统的推荐模型,有效地提高了推荐结果的准确率。

关键词：卷积神经网络矩阵分解推荐算法上下文信息

Characteristics of Particulate matter Emissions for Low-Sulfur Heavy Oil Used in Low-Speed Two-Stroke Diesel Engines of Ocean-Going Ships

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Journal of Thermal Science 2024年第2期33卷 739-750页

作者： WU Gang ma Qianli WEI Lijiang jiang Guohe WANG Tengfei LI Tie Merchant marine College Shanghai Maritime UniversityShanghai201306China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China

In this work,particulate matter(PM) emissions from a large two-stroke,low-speed marine diesel engine were investigated when the engine was operated with low-sulfur heavy fuel oil(HFO) at various *** samples were collected in situ from the engine exhaust to determine the detailed physical and chemical *** nanostructure and morphology of the nanoparticles were analyzed using transmission electron microscopy images(TEM).The results show that volatile organic carbon(OC) accounts for more than 80% in the HFO particles and leads to an increase in particle *** thermodynamic conditions of a low-speed engine favor the behavior of capturing the soluble organic components.A large number of spherical char HFO particles with aerodynamic diameters of 0.2 μm-0.5 μm and a suspected inner metal core were *** two peak aerodynamic diameters of the HFO nanoparticles are 15 nm and 86 *** morphological differences among the HFO nanoparticles in varied engine conditions represent the formation process from primary nascent particles to mature graphitized particles caused by *** above study will be valuable for understanding the characteristics of PM emissions from low-sulfur HFO to achieve the ship PM emissions reduction target.

关键词： low-speed diesel engine maritime regulations heavy fuel oil TEM particles size and distribution

Prediction of surface settlement caused by synchronous grouting during shield tunneling in coarse-grained soils:A combined FEM and machine learning approach

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Underground Space 2024年第3期16卷 206-223页

作者： Chao Liu Zepan Wang hai Liu Jie Cui Xiangyun Huang Lixing ma Shuang Zheng School of Civil Engineering Guangzhou UniversityGuangzhou 510006China Guangdong Engineering Research Center for Underground Infrastructural Protection in Coastal Clay Areas Guangzhou UniversityGuangzhou 510006China Earthquake Engineering Research&Test Center Guangzhou UniversityGuangzhou 510006China CSCEC4 Civil Engineering Co. Ltd.Shenzhen 518052China

This paper presents a surrogate modeling approach for predicting ground surface settlement caused by synchronous grouting during shield tunneling *** proposed method combines finite element simulations with machine learning algorithms and introduces an intelligent optimization algorithm to invert geological parameters and synchronous grouting variables,thereby predicting ground surface settlement without conducting numerous finite element *** surrogate models based on the random forest algorithm are *** first is a parameter inversion surrogate model that combines an artificial fish swarm algorithm with random forest,taking into account the actual number and distribution of complex soil *** second model predicts surface settlement during synchronous grouting by employing actual cover-diameter ratio,inverted soil parameters,and grouting *** avoid changes to input parameters caused by the number of overlying soil layers,the dataset of this model is generated by the finite element model of the homogeneous soil *** surrogate modeling approach is validated by the case history of a large-diameter shield tunnel in Beijing,providing an alternative to numerical computation that can efficiently predict surface settlement with acceptable accuracy.

关键词： Shield tunnel machine learning Synchronous grouting Surrogate modeling Surface settlement

SnapshotPrune: A Novel Bitcoin-Based Protocol Toward Efficient Pruning and Fast Node Bootstrapping

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Tsinghua Science and Technology 2024年第4期29卷 1037-1052页

作者： Pengfei Huang Xiaojun Ren Teng Huang Arthur Sandor Voundi Koe Duncan S Wong hai jiang Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006China Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006Chinaand also with Pazhou LabGuangzhou 510330China

Node synchronization is essential for the stability of the Bitcoin network. Critics have raised doubts about the ability of a new node to quickly and efficiently synchronize with the Bitcoin network and alleviate the storage pressure from existing full nodes to stockpile new data. Basic pruning and other techniques have been explored to address these concerns but have been insufficient to reduce node synchronization delay and effectively suppress the growth of synchronized data. In this study, we propose SnapshotPrune, a novel pruning and synchronization protocol that achieves fast node bootstrapping in the Bitcoin blockchain. Real Bitcoin historical data are leveraged to measure the synchronization time and monitor the network traffic during node bootstrapping. The protocol requires data downloads that are 99.70% less than Bitcoin Core, 81% less than CoinPrune, and 60% less than SnapshotSave, thereby saving 97.23% of download time. Findings show that the proposed design enhances the storage efficiency and reduces the node synchronization delay compared with existing techniques. We hypothesize that the efficiency of this protocol increases with the block height.

关键词： synchronization blockchain Unspent Transaction Output(UTXO)pruning snapshot fast bootstrapping

Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan Yu Shang jiang hai-dong Yu Bi-yu Pang Xin Dong Yi-qian Wang School of mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

Supermassive Primordial Black Holes for Nano-Hertz Gravitational Waves and High-redshift JWST Galaxies

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Research in Astronomy and Astrophysics 2024年第9期24卷 1-6页

作者： hai-Long Huang Yong Cai Jun-Qian jiang Jun Zhang Yun-Song Piao School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Institute for Astrophysics School of PhysicsZhengzhou UniversityZhengzhou 450001China International Centre for Theoretical Physics Asia-Pacific University of Chinese Academy of SciencesBeijing 100190China Taiji Laboratory for Gravitational Wave Universe(Beijing/Hangzhou) University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China

Recently,observational hints for supermassive black holes have been accumulating,prompting the question:Can primordial black holes(PBHs)be supermassive,particularly with masses M■10^(9)M_(⊙)?A supercritical bubble,containing an inflating baby universe,that nucleated during inflation can evolve into a PBH in our observable *** find that when the inflaton slowly transitions past a neighboring vacuum,the nucleation rate of supercritical bubbles inevitably peaks,leading to a mass distribution of multiverse PBHs with a peak mass up to M■10^(11)M_(⊙).Thus,our mechanism naturally provides a primordial origin for supermassive black holes.

关键词： (cosmology:)early universe (cosmology:)inflation (galaxies:)quasars:supermassive black holes

Synergistic effect and heterointerface engineering of cobalt/carbon nanotubes enhancing electromagnetic wave absorbing properties of silicon carbide fibers

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Nano Research 2024年第9期17卷 8479-8486页

作者： Zixiang Zhao Zheyipei ma Zizhao Ding Yanqiong Liu Mingwei Zhang Chao jiang Institute of Powder Metallurgy Research Central South UniversityChangsha 410083China

To improve the synergistic effect between dielectric and magnetic loss is a practical and effective way in optimizing electromagnetic wave absorbing *** composites of metal particles and carbon ligands derived from metal organic frameworks have gained wide *** this study,Co particles and multiwalled carbon nanotubes(CNT)were successfully synthesized covering the surface of silicon carbide(SiC)fibers,and the morphology,interfaces and electromagnetic wave absorption performance were *** sample SiC@Co/CNT,the minimum reflection loss value can reach-70.22 dB at 11.21 GHz with the thickness of 2.12 *** effective absorbing bandwidth can reach up to 6.03 GHz with the thickness of 1.71 mm,which covers the entire Ku *** brings more interfaces between Co particles and CNTs as well as SiC fibers and Co/C *** interfacial polarization has been hugely enhanced,and the microwave absorbing properties have been *** article reports on the impedance matching of magnetic and non-magnetic components and the heterointerface engineering,which can be effective strategy and inspiration to illustrate the relationship between components,structures and functions of electromagnetic wave absorbing materials.

关键词： metal organic frameworks Co nanocrystals carbon nanotubes Schottky heterointerfaces synergistic effect

A Simple and Effective Surface Defect Detection Method of Power Line Insulators for Difficult Small Objects

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Computers, materials & Continua 2024年第4期79卷 373-390页

作者： Xiao Lu Chengling jiang Zhoujun ma haitao Li Yuexin Liu State Grid jiangsu Electric Power Co. Ltd.Nanjing210024China State Grid Changzhou Power Supply Company Changzhou213003China

Insulator defect detection plays a vital role in maintaining the secure operation of power *** address the issues of the difficulty of detecting small objects and missing objects due to the small scale,variable scale,and fuzzy edge morphology of insulator defects,we construct an insulator dataset with 1600 samples containing flashovers and *** a simple and effective surface defect detection method of power line insulators for difficult small objects is ***,a high-resolution featuremap is introduced and a small object prediction layer is added so that the model can detect tiny ***,a simplified adaptive spatial feature fusion(SASFF)module is introduced to perform cross-scale spatial fusion to improve adaptability to variable multi-scale ***,we propose an enhanced deformable attention mechanism(EDAM)*** integrating a gating activation function,the model is further inspired to learn a small number of critical sampling points near reference *** the module can improve the perception of object *** experimental results indicate that concerning the dataset of flashover and breakage defects,this method improves the performance of YOLOv5,YOLOv7,and *** practical application,it can simply and effectively improve the precision of power line insulator defect detection and reduce missing detection for difficult small objects.

关键词： Insulator defect detection small object power line deformable attention mechanism

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

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Hepatobiliary & Pancreatic Diseases International 2024年第3期23卷 300-309页

作者： Qing Huang Jia-Wen Liu hai-Bin Dong Zheng-Jie Wei Jin-Zhe Liu Yu-Tang Ren Xuan jiang Bo jiang Department of Gastroenterology Beijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijing 102218China

Background:Visceral adipose tissue(VAT)has been linked to the severe acute pancreatitis(SAP)prognosis,although the underlying mechanism remains *** has been reported that pyroptosis worsens *** present study aimed to verify whether mesenteric adipose tissue(maT,a component of VAT)can cause secondary intestinal injury through the pyroptotic ***:Thirty-six male Sprague Dawley(SD)rats were divided into six different *** rats were randomly divided into the SAP and control *** monitored the changes of maT and B lymphocytes infiltration in maT of SAP *** SAP rats were injected with maT B lymphocytes or phosphate buffer solution(PBS).The remaining twelve SAP rats were first injected with maT B lymphocytes,and then with MCC950(NLRP3 inhibitor)or *** collected blood and tissue samples from pancreas,gut and maT for ***:Compared to the control rats,the SAP group showed inflammation in maT,including higher expression of tumor necrosis factor(TNF-α)and interleukin-6(IL-6),lower expression of IL-10,and histological *** cytometry analysis revealed B lymphocytes infiltration in maT but not T lymphocytes and *** SAP rats also exhibited intestinal injury,characterized by lower expression of zonula occludens-1(ZO-1)and occludin,higher levels of lipopolysaccharide and diamine oxidase,and pathological *** expression of NLRP3 and n-GSDMD,which are responsible for pyroptosis,was increased in the intestine of SAP *** injection of maT B lymphocytes into SAP rats exacerbated the inflammation in *** upregulation of pyroptosis reduced tight junction in the intestine,which contributed to the SAP progression,including higher inflammatory indicators and worse histological *** administration of MCC950 to SAP+maT B rats downregulated pyroptosis,which subsequently improved the intestinal barrier and ameliorated inflammatory response of ***:In SAP,maT B lymphocytes aggravated local

关键词： Acute pancreatitis Mesenteric adipose tissue B lymphocyte Intestinal barrier Pyroptosis