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Characteristics of transmitting channel wave in a coal seam

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Mining Science and Technology 2009年第3期19卷 331-336页

作者： YANG Zhen ge Mao-chen WANG Shu-gang School of Mines China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China College of Earth and Mineral Scienc The Penn State University PA 16802 USA

An embedded underground coal seam carries channel waves of low seismic velocity along a stratigraphic rock-coal-rock *** a homogeneous and isotropic seam, seismic waves propagate as trapped waves within the seam, which leads to propagation of channel *** describe how to set up a field test for transmission in order to acquire channel waves in a coal *** channel wave signals are non-stationary in their frequencies and amplitudes, a necessary velocity spectrum and wavelet transformation analysis are applied to interpret the characteristics of channel *** advantage of using a wavelet transformation is that different resolutions can be obtained at different times and different *** to analysis of the seismic signals acquired in the S7 sensor hole, it was clearly shown that the characteristics of channel waves are lower frequencies and attenuation which can guide an effective wave for detecting voids, boundaries and faults in coal seams with strong roofs and floors.

关键词： in-seam seismic technique channel wave coal seam time-frequency domain Gabor wavelet velocity spectrum

Polarons in alkaline-earth-like atoms with multiple background Fermi surfaces

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Frontiers of physics 2018年第4期13卷 185-193页

作者： Jin-ge chen Yue-Ran Shi Xiang Zhang Wei Zhang Department of Physics Renmin University of China Beijing 100872 China Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices Renmin University of China Beijing 100872 China

We study the impurity problem in a Fermi gas of 173Yb atoms near an orbital Feshbach resonance （OFR）, where a single moving particle in the 3p0 state interacts with two background Fermi seas of particles in different nuclear states of the ground 1S0 manifold. By employing wave function ansatz to molecule and polaron states, we investigate various properties of the molecule, the attractive polaron, and the repulsive polaron states. In comparison to the case where only one Fermi sea is populated, we find that the presence of an additional Fermi sea acts as an energy shift between the two channels of the OFR. In addition, quantum fluctuations near the Fermi level can also induce sizable effects to various properties of the attractive and repulsive polarons.

关键词： Fermi gas alkaline-earth atoms orbital Feshbach resonance polaron

Anharmonicity induced thermal modulation in stressed graphene

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Science China(Physics,Mechanics & Astronomy) 2017年第7期60卷 48-52页

作者： Jian Jun Jiang Wei cheng Fu Ji ge chen Hong Zhao Department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology Shanghai Institute of Applied PhysicsChinese Academy of Sciences

Thermal properties are essentially decided by atomic geometry and thus stress is the most direct way for manipulating. In this paper, we investigate stress modulation of thermal conductivity of graphene by molecular dynamics simulations and discuss the underlying microscopic mechanism. It is found that thermal conductivity of ftexural-free graphene increases with compression and decreases with strain, while thermal conductivity of flexural-included graphene decreases with both compression and strain. Such difference in thermal behavior originates from the changes in the anharmonicity of the interatomic potential, where the wrinkle scattering is responsible for the thermal conductivity diminishment in flexural-included graphene under strain. By comparing the results obtained from the Tersoff and AIREBO potentials, it is revealed that the degree of the symmetry of interatomic potential determines the thermal conductivity variation of graphene. Our results indicate that the symmetry of interatomic potential should be taken into careful consideration in constructing the lattice model of graphene.

关键词： graphene heat conduction thermal modulation stressed graphene anharmonicity

Differentially Private Real-Time Streaming Data Publication Based on Sliding Window Under Exponential Decay

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Computers, Materials & Continua 2019年第1期58卷 61-78页

作者： Lan Sun chen ge Xin Huang Yingjie Wu Yan Gao College of Mathematics and Computer Science Fuzhou UniversityXue Yuan RoadNo.2Fuzhou350116China Amazon 410 Terry Avenue NorthSeattleWashington98109USA

Continuous response of range query on steaming data provides useful information for many practical applications as well as the risk of privacy *** existing research on differential privacy streaming data publication mostly pay close attention to boosting query accuracy,but pay less attention to query efficiency,and ignore the effect of timeliness on data *** this paper,we propose an effective algorithm of differential privacy streaming data publication under exponential decay ***,by introducing the Fenwick tree to divide and reorganize data items in the stream,we achieve a constant time complexity for inserting a new item and getting the prefix ***,we achieve time complicity linear to the number of data item for building a *** that,we use the advantage of matrix mechanism to deal with relevant queries and reduce the global *** addition,we choose proper diagonal matrix further improve the range query ***,considering about exponential decay,every data item is weighted by the decay *** putting the Fenwick tree and matrix optimization together,we present complete algorithm for differentiate private real-time streaming data *** experiment is designed to compare the algorithm in this paper with similar algorithms for streaming data release in exponential *** results show that the algorithm in this paper effectively improve the query efficiency while ensuring the quality of the query.

关键词： Differential privacy streaming data publication exponential decay matrix mechanism sliding window

基于SSA-BP的爆破振动峰值速度预测研究

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爆破 2024年第3期41卷 205-211页

作者：李攀云高文学张小军何茂林葛晨雨王林北京工业大学城市建设学部北京100124 北京市政路桥股份有限公司北京100045

为了精准预测爆破振动峰值速度(PPV),有效降低爆破振动的危害,以星光一号露天矿山爆破工程为依托,选取爆心距、堵塞长度、最小抵抗线、炸药单耗、最大单孔装药量、总延期时间、最大单响药量等7个影响因素作为输入变量,采用灰色关联分析... 详细信息

为了精准预测爆破振动峰值速度(PPV),有效降低爆破振动的危害,以星光一号露天矿山爆破工程为依托,选取爆心距、堵塞长度、最小抵抗线、炸药单耗、最大单孔装药量、总延期时间、最大单响药量等7个影响因素作为输入变量,采用灰色关联分析法评估各因素与PPV之间的相关性,构建麻雀搜索算法(SSA)优化BP神经网络的爆破峰值振速预测模型,对三向峰值振动速度进行预测,并与BP神经网络模型预测结果进行对比分析,得到SSA-BP神经网络模型预测结果的平均误差分别为6.08%、7.34%、1.91%,BP神经网络模型预测结果的平均误差分别为22.19%、54.01%、25.29%。研究结果表明:SSA-BP神经网络模型全面考虑了多种爆破设计参数对振动峰值速度的影响;麻雀搜索优化算法有效解决了传统BP神经网络模型容易陷入局部最优的问题,预测结果更精确,与振速监测值吻合度更高、误差更小;并且极大地缩短了样本数据的学习训练时间,加快BP神经网络预测模型的收敛速度,可为类似露天爆破工程质点峰值振速的预测提供借鉴。

关键词：爆破振动露天矿山质点峰值振速预测 BP神经网络 SSA-BP神经网络模型

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Climate background of the evolution from Paleolithic to Neolithic cultural transition during the last deglaciation in the middle reaches of the Yellow River

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Chinese Science Bulletin 2002年第1期47卷 71-75页

作者： Zhengkai Xia ge chen Gongwang Zheng Fuyou chen Junqing Han Peking Univ Dept Urban & Environm Sci Beijing 100871 Peoples R China

Shizitan in Jixian County, Shanxi Province, is a site of transitional period from Paleolithic to Neolithic. The dating and the sporopollen analysis show that the middle reaches of the Yellow River where the site is located had been maintaining a steppe environment during 35.1-9.4 kaBP, in which, 35.1-17 kaBP belonged to the last glacial. With cold and dry climate, this period featured a desert steppe environment. In the late of this period, the area had a cold and half-humid steppe environment. The 17.0-11.9 kaBP belonged to the early- and mid-period of the last deglaciation. Mild and half-arid steppe alternates with mild and half-arid steppe, with a small amount of deciduous broadleaf species. During the period of 11.9-10.5 kaBP, cold and dry glacial climate appeared once more, featuring a desert steppe environment. During 10.5-9.4 kaBP, it is mild and half-arid, and later transited toward warm and half-humid. The early phase of this period featured a steppe environment and the later transited into a

关键词： Jixian County in Shanxi Province Shizitan site sporo-pollen analysis last deglaciation Paleolithic-Neolithic cultural transition.

持续高温条件对4个百香果品种开花坐果习性及光合作用的影响

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果树学报 2024年第7期41卷 1401-1409页

作者：黄显雅陈格黄永才桂杰黄诚梅鞠莹盛静文蒋萍杨柳广西壮族自治区农业科学院亚热带作物研究所南宁530001 广西壮族自治区农业科学院·广西作物遗传改良重点实验室·农业农村部百香果生物学与遗传育种重点实验室南宁530004

【目的】评价田间持续高温条件下钦蜜9号、小黄金、台农1号和满天星4个百香果品种的耐热性,为未来耐高温育种材料快速筛选和广西百香果夏季种植布局提供理论参考。【方法】选择日最高温连续5 d超过32℃(即持续高温)的时段,到南宁和贵港... 详细信息

【目的】评价田间持续高温条件下钦蜜9号、小黄金、台农1号和满天星4个百香果品种的耐热性,为未来耐高温育种材料快速筛选和广西百香果夏季种植布局提供理论参考。【方法】选择日最高温连续5 d超过32℃(即持续高温)的时段,到南宁和贵港的百香果种植基地进行4个百香果品种开花坐果及光合作用调查。采用田间调查方法记录百香果开花坐果情况,同时利用LI-6400XT便携式光合作用测量系统获得百香果的光合作用数据,结合统计学方法探讨持续高温条件下4个百香果品种的开花坐果和光合作用差异,并分析开花坐果和光合作用之间的关联性。【结果】两地持续高温条件下开花坐果和光合作用数值最高的是钦蜜9号,其次是小黄金和台农1号,最低的是满天星。在开花坐果方面,钦蜜9号的平均芽点数、平均花朵数、平均花芽数和平均挂果数显著高于其他3个品种(p<0.05),最高分别可达到71.85节·株^(-1)、20.90朵·株^(-1)、21.60个·株^(-1)和6.25个·株^(-1)。在光合作用方面,钦蜜9号的净光合速率(P_(n))、气孔导度(G_(s))、胞间CO_(2)浓度(C_(i))和蒸腾速率(T_(r))分别是满天星的3.64倍、11.62倍、5.46倍和6.60倍,差异显著(p<0.05)。【结论】钦蜜9号具有较强的耐热性,可作为夏季主栽品种在全广西推广种植或与其他品种配套种植,以改变其他品种百香果由于夏季高温产量降低导致的市场萎缩现象,增强广西百香果主产区优势,同时可以将其作为耐热育种的亲本材料。

关键词：百香果高温条件开花坐果习性光合特征

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Functionalized graphene oxide nanosheets with unique three-inone properties for efficient and tunable antibacterial applications

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Nano Research 2021年第1期14卷 185-190页

作者： Bo-Yao Lu Guan-Yin Zhu chen-Hao Yu ge-Yun chen Chao-Liang Zhang Xin Zeng Qian-Ming chen Qiang Peng State Key Laboratory of Oral Diseases National Clinical Research Center for Oral DiseasesWest China Hospital of StomatologySichuan UntiversityChengdu 610041China

Developing antibiotics-independent antibacterial agents is of great importance since antibiotic therapy faces great challenges from drug *** oxide(GO)is a promising agent due to its natural antibacterial mechanisms,such as sharp edgemediated cutting ***,the antibacterial activity of GO is limited by its negative charge and low photothermal ***,the amino-functionalized GO nanosheets(AGO)with unique three-in-one properties were *** essential properties(positive charge,strong photothermal effect,and natural cutting effect)were integrated into *** positive charge(30 mV)rendered AGO a strong interaction force with model pathogen Streptococcus mutans(330 nN).The natural cutting effect of 100 ng·mL^(-1)AGO caused 27%loss of bacterial viability after incubation for 30 *** importantly,upon the near-infrared irradiation for just 5 min,the three-in-one properties of AGO caused 98%viability *** conclusion,the short irradiation period and the tunable antibacterial activity confer the three-in-one AGO a great potential for clinical use.

关键词： nanoparticles nanomaterials carbon nano-bio interaction dental caries antimicrobial

geographical Information Visualization on a Panoramic Sphere in an Immersive Environment

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Journal of Ocean University of China 2023年第4期22卷 961-974页

作者： MA Ying TIAN Fenglin LIU Wen TANG Moran LI Jinyu chen ge Frontiers Science Center for Deep Ocean Multispheres and Earth System School of Marine TechnologyOcean University of ChinaQingdao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQingdao 266100China Faculty of Information Science and Engineering Ocean University of ChinaQingdao 266100China

In this paper,we propose a novel approach to visualizing global geographical information:a panoramic sphere in an immersive *** whole geographical surface can be observed through the rotating of heads as the viewpoint of the panoramic sphere is inside the *** compared three approaches to visualizing the earth for rendering the geographical information in a virtual reality *** the tasks of terrestrial and marine geographical information,we compare the visualization effects on a)a globe,b)a flat map and c)a panoramic *** geographical information tasks include the area comparison and direction *** geographical information tasks contain the visualization of sea surface temperature and sea surface *** terrestrial geographical information tasks,the experimental results show that the panoramic sphere outperforms the globe and the flat map,with a higher average accuracy and a shorter *** marine geographical information task,the panoramic sphere visualization is also superior to the flat map and the globe in an immersive environment for the sea surface temperature data and the sea surface current *** all three visualization experiments,the panoramic sphere is most preferred by the participants,particularly for global,transcontinental and transoceanic needs.

关键词： the panoramic sphere immersive environment virtual reality oceanographic information visualization