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Vertex Disjoint Cycles in Intersection Graphs of Bases of Matroids

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Wuhan University Journal of Natural Sciences 2017年第6期22卷 461-464页

作者： zhang yinghao CHI Hongmei College of Science Huazhong Agriculture University Wuhan430070 Hubei China

The intersection graph of bases of a matroid M=（E, B） is a graph G=GI（M） with vertex set V（G） and edge set E（G） such that V（G）=B（M） and E（G）={BB′：｜B∩B′｜ ≠0, B, B′∈B（M）, where the same notation is used for the vertices of G and the bases of M. Suppose that｜V（GI（M））｜ =n and k1＋k2＋…＋kp=n, where ki is an integer, i=1, 2,…, p. In this paper, we prove that there is a partition of V（GI（M）） into p parts V1 , V2,…, Vp such that ｜Vi｜ =ki and the subgraph Hi induced by Vi contains a ki-cycle when ki ≥3, Hi is isomorphic to K2 when ki =2 and Hi is a single point when ki =1.

关键词： matroid intersection graph base cycle

An Underwater Target Detection Algorithm Based on Attention Mechanism and Improved YOLOv7

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Computers, Materials & Continua 2024年第2期78卷 2829-2845页

作者： Liqiu Ren Zhanying Li Xueyu He Lingyan Kong yinghao zhang College of Information Science and Engineering Dalian Polytechnic UniversityDalian116034China

For underwater robots in the process of performing target detection tasks,the color distortion and the uneven quality of underwater images lead to great difficulties in the feature extraction process of the model,which is prone to issues like error detection,omission detection,and poor ***,this paper proposed the CER-YOLOv7(CBAM-EIOU-RepVGG-YOLOv7)underwater target detection *** improve the algorithm’s capability to retain valid features from both spatial and channel perspectives during the feature extraction phase,we have added a Convolutional Block Attention Module(CBAM)to the backbone *** Reparameterization Visual Geometry Group(RepVGG)module is inserted into the backbone to improve the training and inference *** Efficient Intersection over Union(EIoU)loss is also used as the localization loss function,which reduces the error detection rate and missed detection rate of the *** experimental results of the CER-YOLOv7 algorithm on the UPRC(Underwater Robot Prototype Competition)dataset show that the mAP(mean Average Precision)score of the algorithm is 86.1%,which is a 2.2%improvement compared to the *** feasibility and validity of the CER-YOLOv7 are proved through ablation and comparison experiments,and it is more suitable for underwater target detection.

关键词： Deep learning underwater object detection improved YOLOv7 attention mechanism

Discharge and mass transfer characteristics of atmospheric pressure gas-solid two-phase gliding arc

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Plasma Science and Technology 2024年第9期26卷 88-96页

作者： Min ZHU Yuchen PING yinghao zhang Chaohai zhang Shuqun WU Department of Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106People’s Republic of China

In this work,a gas-solid two-phase gliding arc discharge(GS-GAD)reactor was *** arc was formed in the gap between the blade electrodes,and solid powder was deposited on the sieve plate positioned beneath the blade electrodes.A range of experimental parameters,including the inter-electrode spacing,gas flow rate,applied voltage,and the type of the powder,were systematically varied to elucidate the influence of solid powder matter on the dynamics of gliding arc discharge(GAD).The discharge images were captured by ICCD and digital camera to investigate the mass transfer characteristics of GS-GAD,and the electrical parameters,such as the effective values of voltage,current,and discharge power were record to reveal the discharge characteristics of *** results demonstrate that powder undergoes spontaneous movement towards the upper region of the gliding arc due to the influence of electric field *** the discharge voltage,decreasing relative dielectric constant of the powder and reducing the electrode-to-sieve-plate distance all contribute to a greater involvement of powder in the GAD process,subsequently resulting in an enhanced powder concentration within the GAD ***,powder located beneath the gliding arc experiences downward resistance caused by the opposing gas flow and *** gas flow rate notably hampers the powder concentration within the discharge region,and the velocity of powder motion in the upper part of the GAD region is *** the condition of electrode-to-sieve-plate distance of 30 mm,gas flow rate of 1.5 L/min,and peak-to-peak voltage of 31 kV,the best combination of arc gliding and powder spark discharge phenomena can be achieved with the addition of Al_(2)O_(3) powder.

关键词： gliding arc discharge atmospheric pressure plasma multiphase discharge mass transfer

Plasma propagation in single-particle packed dielectric barrier discharges:joint effects of particle shape and discharge gap

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Plasma Science and Technology 2022年第6期24卷 124-134页

作者： Min ZHU Shengyu HU yinghao zhang Shuqun WU Chaohai zhang Department of Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106People's Republic of China

In this work,a single Al_(2)O_(3) particle packed dielectric barrier discharge(DBD)reactor with adjustable discharge gap is built,and the influences of the particle shape(ball and column)and the residual gap between the top electrode and particle on the electrical and optical characteristics of plasma are *** research confirms that streamer discharge and surface discharge are the two main discharge patterns in the single-particle packed DBD *** strong electric field distortion at the top of the ball or column caused by the dielectric polarization effect is an important reason for the formation of streamer *** length of streamer discharge is proportional to the size of the residual gap,but the number of discharge times of a single voltage cycle shows an opposite *** to the column,a smooth spherical surface is more conducive to the formation of large and uniform surface *** surface discharge area and the discharge intensity reach a maximum when the gap is equal to the diameter of the *** in all,the results of this study will provide important theoretical support for the establishment of the synergistic characteristics of discharge and catalysis in plasma catalysis.

关键词： low-temperature plasma packed-bed dielectric barrier discharge streamer discharge surface discharge plasma catalysis

Perspectives of metal-organic framework nanosystem to overcome tumor drug resistance

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Cancer Drug Resistance 2022年第4期5卷 954-970页

作者： Huafeng Wang Shi Li Yiting Yang Lei zhang yinghao zhang Tianxiang Wei School of Environment Nanjing Normal UniversityNanjing 210023JiangsuChina School of Chemistry and Materials Science Nanjing Normal UniversityNanjing 210023JiangsuChina.

Cancer is one of the most harmful diseases in the world, which causes huge numbers of deaths every year. Manydrugs have been developed to treat tumors. However, drug resistance usually develops after a period of time,which greatly weakens the therapeutic effect. Tumor drug resistance is characterized by blocking the action ofanticancer drugs, resisting apoptosis and DNA repair, and evading immune recognition. To tackle tumor drugresistance, many engineered drug delivery systems (DDS) have been developed. Metal-organic frameworks(MOFs) are one kind of emerging and promising nanocarriers for DDS with high surface area and abundant activesites that make the functionalization simpler and more efficient. These features enable MOFs to achieveadvantages easily towards other materials. In this review, we highlight the main mechanisms of tumor drugresistance and the characteristics of MOFs. The applications and opportunities of MOF-based DDS to overcometumor drug resistance are also discussed, shedding light on the future development of MOFs to address tumor drugresistance.

关键词： Metal-organic framework drug resistance drug delivery cancer therapy nanosystem

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苦草对水流结构的影响研究

水科学进展 2015年第1期26卷 99-106页

作者：张英豪赖锡军中国科学院南京地理与湖泊研究所流域地理学重点实验室江苏南京210008 中国科学院大学北京100049

为研究沉水植被对水流结构的影响,以苦草为对象,利用实验室水槽实验研究了含淹没水生植被水流时均流速、雷诺应力及紊动能的垂向分布特征。受苦草冠层的影响,时均流速在冠顶以上呈对数分布,且随着流量的增加,冠层倾伏高度降低,对数剖面... 详细信息

为研究沉水植被对水流结构的影响,以苦草为对象,利用实验室水槽实验研究了含淹没水生植被水流时均流速、雷诺应力及紊动能的垂向分布特征。受苦草冠层的影响,时均流速在冠顶以上呈对数分布,且随着流量的增加,冠层倾伏高度降低,对数剖面愈加明显;冠层内部,由于冠层阻流面积在垂向分布上的差异,冠层内时均流速出现逆梯度分布,且在床面附近出现局部流速最大值。雷诺应力在冠顶附近达到最大值,并向水面与床底方向逐渐减小;受逆流速梯度的影响,冠层内部雷诺应力出现负值以及局部最大值。雷诺应力产生的剪切紊动使得紊动能在冠顶处最大,并向水面与床底进行垂向传输;受紊动传输距离的限制,冠层底部以叶片后产生的尾流紊动为主,紊动能较小。

关键词：水生植被时均流速雷诺应力紊动能

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卫星广播网络环境下区块链协议的初步研究

西安电子科技大学学报 2020年第5期47卷 11-18,27页

作者：张颖浩刘肖凡东南大学计算机科学与工程学院江苏南京211189 香港城市大学媒体与传播系香港特别行政区999077

吞吐量低下一直是阻碍区块链技术大规模应用的最大障碍。近些年来,研究者们提出了多种方案来提升吞吐量,虽然取得了一定的效果,但是并不能从根本上解决问题。区块链吞吐量的瓶颈在于底层互联网中数据广播任务的低效与缺陷,因此提出用卫... 详细信息

吞吐量低下一直是阻碍区块链技术大规模应用的最大障碍。近些年来,研究者们提出了多种方案来提升吞吐量,虽然取得了一定的效果,但是并不能从根本上解决问题。区块链吞吐量的瓶颈在于底层互联网中数据广播任务的低效与缺陷,因此提出用卫星广播网络代替互联网来进行数据广播与共识任务。详细地描述了数据广播机制和共识算法,同时提出一种自动恢复机制来解决卫星广播独有的通信问题。模拟环境中的实验结果显示,该机制具有更小的通信代价,从而使区块链网络吞吐量大幅提高。理论上,当卫星的广播带宽为20Gb/s时,基于卫星广播的区块链系统的吞吐量可达约6000000交易数每秒。

关键词：区块链卫星广播吞吐量

单向明渠流与波浪作用下植被对水沙运动影响研究综述

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水科学进展 2021年第2期32卷 309-319页

作者：张英豪赖锡军唐彩红聊城大学环境与规划学院山东聊城252000 中国科学院南京地理与湖泊研究所中国科学院流域地理学重点实验室江苏南京210008 华北电力大学水利与水电工程学院北京102206

作为河、湖以及滨海湿地生态系统中必不可少的组成部分,水生植被具有重要的生态服务价值,且许多生态服务价值是通过改变水体动力条件实现的。含植被水流研究不仅可用于科学阐明水生植被的生态环境效应,还能指导河湖生态系统修复及污染... 详细信息

作为河、湖以及滨海湿地生态系统中必不可少的组成部分,水生植被具有重要的生态服务价值,且许多生态服务价值是通过改变水体动力条件实现的。含植被水流研究不仅可用于科学阐明水生植被的生态环境效应,还能指导河湖生态系统修复及污染治理的工程实践。本文考虑单向明渠流与波浪2种水动力环境,对国内外有关水生植被对水流结构以及泥沙运动影响研究的主要成果进行梳理。单向明渠流条件下,植被对水动力的影响研究主要集中于植被对水流阻力的影响以及冠层内水体的紊动结构与紊动尺度特征;波浪条件下,植被对波高与波浪流速的减弱作用以及冠层内水体的时均与紊动结构特征是研究重点。受水动力条件控制,植被影响下的泥沙运动特征也受到广泛关注,且研究焦点为单向明渠流条件下水生植被对泥沙起动与输移的影响以及波浪条件下植被对床底泥沙再悬浮的影响。

关键词：水流结构泥沙运动单向明渠流波浪水生植物

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基于频谱分析的水体波浪-紊动流速分离方法

湖泊科学 2022年第2期34卷 643-651页

作者：段雨新张占飞张英豪聊城大学地理与环境学院聊城252059 聊城大学季羡林学院聊城252059

根据波浪影响下水质点运动速度的频谱分布特征,本文提出了一种用于分离水体波浪轨道流速与紊动流速的分离方法.该方法仅需通过一台流速仪对水体瞬时流速进行高频测量,便可对水体波浪紊动流速进行分离,实现受波浪影响水体的紊动分析.通... 详细信息

根据波浪影响下水质点运动速度的频谱分布特征,本文提出了一种用于分离水体波浪轨道流速与紊动流速的分离方法.该方法仅需通过一台流速仪对水体瞬时流速进行高频测量,便可对水体波浪紊动流速进行分离,实现受波浪影响水体的紊动分析.通过验证,频谱分析法不仅能够用于实验室中规则波浪条件下水体波浪紊动流速的分离,还能够对野外不规则波条件下水质点运动速度进行分离.分离过程中,波浪窗口的频域设置可影响流速分离效果.当频域设置位于波浪窗口以外时,频域设置范围大小对分离结果影响较小,且均能对波浪紊动流速进行有效分离.此外,流速测量频率对分离结果产生影响.当流速测量频率较低时,瞬时流速不能反映水体紊动信息,频谱分析法对流速的分离效果较差.

关键词：流速频谱流速分离波浪流速水体紊动紊动能