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Precursor synthesis strategy for polycyclic aromatic conjugated polymers on the application of supercapacitors

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Science China Chemistry 2018年第2期61卷 192-199页

作者： Zhenhua Zhang Weitao ma Biao Xu Xuehong Zhou Cong Wang Zengqi Xie Linlin Liu Yuguang ma Institute of Polymer Optoelectronic materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of Technology

Polycyclic aromatics (PCAs) possess excellent photoelectric properties, but the construction of such compounds has been a quite challenging subject of study, mainly due to very low solubility. Herein we report a precursor synthesis strategy for polycyclic aromatic conjugated polymers. A soluble precursor polymer, that containing fusible "double u-shaped aromatic"(DuA) and perylenetetracarboxydiimide (PDI) units, was firstly synthesized by Suzuki coupling. The stereo aromatic units in polymer backbone were found to be converted into polycyclic aromatic units, i.e. hexa-peri-hexabenzocoronene (HBC), by chemical or electrochemical oxidation, which resulted in a formation of insoluble polycyclic aromatic conjugated polymers. The electrochemical oxidations that occurred at the interface of electrode and solution exhibited higher cyclization reactivity and leads to the formation of high quality films on the electrode surface. Characterization by Raman and uV-visible (uV-Vis) spectroscopy validated the successful formation of this HBC structure. Some potential applications of such thin films are being explored, and here we focus on the characteristics of supercapacitors based on their excellent electrochemical properties.

关键词： polycyclic aromatics conjugated polymer electrochemical deposition supercapacitor

Simulation study on cooperation behaviors and crowd dynamics in pedestrian evacuation

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Chinese Physics B 2020年第3期29卷 488-495页

作者： Ya-Ping ma Hui Zhang China Research Center for Emergency management Wuhan University of TechnologyWuhan 430070China School of Safety Science and Emergency management Wuhan University of TechnologyWuhan 430070China Institute of Public Safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 100084China

Pedestrian evacuation is actually a process of behavioral evolution. Interaction behaviors between pedestrians affect not only the evolution of their cooperation strategy, but also their evacuation paths-scheduling and dynamics features. The existence of interaction behaviors and cooperation evolution is therefore critical for pedestrian evacuation. To address this issue, an extended cellular automaton(CA) evacuation model considering the effects of interaction behaviors and cooperation evolution is proposed here. The influence mechanism of the environment factor and interaction behaviors between neighbors on the decision-making of one pedestrian to path scheduling is focused. Average payoffs interacting with neighbors are used to represent the competitive ability of one pedestrian, aiming to solve the conflicts when more than one pedestrian competes for the same position based on a new method. Influences of interaction behaviors, the panic degree and the conflict cost on the evacuation dynamics and cooperation evolution of pedestrians are discussed. Simulation results of the room evacuation show that the interaction behaviors between pedestrians to a certain extent are beneficial to the evacuation efficiency and the formation of cooperation behaviors as well. The increase of conflict cost prolongs the evacuation time. Panic emotions of pedestrians are bad for cooperation behaviors of the crowd and have complex effects on evacuation time. A new self-organization effect is also presented.

关键词： pedestrian evacuation evacuation time interaction behaviors cooperation

计时电量法测定4,5-二氮芴-9-酮的扩散系数和反应速率常数

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北京理工大学学报 2014年第6期34卷 650-654页

作者：吕桂琴马淑贤北京理工大学化学学院北京100081

运用循环伏安法测定4,5-二氮芴-9-酮(DAFO)在DMF溶液中不同扫描速率时的循环伏安图,出现2对峰形良好的氧化还原峰;采用计时电量法通过控制阶跃电位,测得不同温度下DAFO在DMF溶液中的扩散系数和反应速率常数,293 K时扩散系数为5.39×10^(... 详细信息

运用循环伏安法测定4,5-二氮芴-9-酮(DAFO)在DMF溶液中不同扫描速率时的循环伏安图,出现2对峰形良好的氧化还原峰;采用计时电量法通过控制阶跃电位,测得不同温度下DAFO在DMF溶液中的扩散系数和反应速率常数,293 K时扩散系数为5.39×10^(—6)cm^2·s^(—1);当选择阶跃电位使电极过程处于扩散和电化学混合控制时,测得不同电位的反应速率常数κ_f.根据不同温度下的标准速率常数κ_0,得到表观活化能E_a为10.5 kJ·mol^(—1).

关键词： 4,5-二氮芴-9-酮循环伏安计时电量扩散系数反应速率常数

A Survey on Technologies and Challenges of LTE-u

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Computer Systems Science & Engineering 2022年第4期41卷 321-337页

作者： Tong Gan Shi-You Wang Qiang ma Yi-Dong Jia Yun-Yun ma Beijing Metro Consultancy Corporation Ltd. Beijing100071China School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China School of Electronic Electrical and Systems Engineering University of BirminghamBirminghamB152TTUnited Kingdom

The rapid growth of mobile data trafﬁc has caused great pressure on the limited spectrum resources,and there must be some better methods to deal with this *** innovative technology of Long-Term Evolution(LTE)using the unlicensed spectrum,known as LTE-unlicensed(LTE-u),has been proposed to effectively alleviate the shortage of authorized band ***-u has explored a lot of potential capacity in mobile communication systems with limited authorized spectrum resources,and improved the spectrum utilization of unauthorized frequency ***,LTE-u is still facing challenges in its *** this paper,we summarize the key features of LTE-u and the coex-istence of LTE-u with Wi-Fi in the unlicensed *** analyze the key technologies(including carrier aggregation,HARQ,interference cancelation,and centralized scheduling),the operating modes and deployment scenarios(including carrier aggregation LTE-u,duty cycle LTE-u,and standalone LTE-u),and the advantages(including anchored LTE-u and Standalone LTE-u scenarios),as well as main technical *** then address the different management mechanisms of LTE-u and Wi-Fi(including the differences between the maC layer and physical layer),the types of coexistence technology classiﬁcation(including channel separation and channel sharing technologies),and directions for future *** hope that this comprehensive survey spurs further research in this promising area.

关键词： LTE-u unlicensed spectrum coexistence technology

Development and evaluation of corrosion resistant coating for expandable rock bolt against highly corrosive ground conditions

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International Journal of Mining Science and Technology 2018年第1期28卷 145-151页

作者： Kevin Jinrong ma John Stankus Dakota Faulkner Keystone Mining Services LLC of Jennmar Corporation Inc

Expandable rock bolts are widely used in hard rock mines as an efficient ground control ***, capacity and service life can be significantly reduced if the metallic body is subjected to *** some hard rock mines in the u.S., highly corrosive ground conditions exist, and it has been reported that inflatable rock bolts have corroded within a few months after *** provide mining industry a cost-effective inflatable bolt and combat the corrosion issues, Jennmar Corporation, Inc.,and its subsidiary Keystone Mining Services, LLC(KMS), analyzed corroded bolt samples, identified root causes, evaluated properties of various coating materials, and developed a new inflatable rock bolt,Python M3^(TM), that is protected with an innovative PyFlexu2^(TM)*** new generation Python M3^(TM) features improved steel chemistry for reliable performance, modified profile for better inflation, and surface preparation and coating *** PyFlexu2^(TM)is impervious to liquid and air, durable, and uV *** a flexible, adhesive, and highly corrosion-resistant undercoating, and a very hard sacrificial surface coating, the PyFlexu2^(TM)coating system provides the Python M3^(TM)superior protection against chemical corrosion and physical scratch *** under-coating has exceptional flexibility and adhesion to prevent coating micro-cracks or fractures after bolt inflation and possesses excellent corrosion resistance to acids(pH 11), fuels, and salt *** corrosion and scratch resistant PyFlexu2^(TM)coating offers very effective bolt protection for extra longevity in highly corrosive *** Python M3^(TM)coated with PyFlexu2^(TM)has been tested in the most challenging conditions,including laboratory corrosion tests in extreme acidic and basic solvents, rock slurry, and borehole scratch insertion *** demonstrated corrosion and scratch resistance, the product has been greatly welcomed by hard rock min

关键词： Rock bolt Hard rock Corrosive ground condition Bolt corrosion

Integral Equation Method for a Non-Selfadjoint Steklov Eigenvalue Problem

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Communications in Computational Physics 2022年第5期31卷 1546-1560页

作者： Yunyun ma Jiguang Sun School of Computer Science and Technology Dongguan University of TechnologyDongguan 523808P.R.China Department ofmathematical Sciences Michigan TechnologicalUniversityHoughtonMI 49931U.S.A.

We propose a numerical method for a non-selfadjoint Steklov eigenvalue problem of the Helmholtz *** problem is formulated using boundary *** Nyström method is employed to discretize the integral operators,which leads to a non-Hermitian generalized matrix eigenvalue *** spectral indicator method(SIM)is then applied to calculate the(complex)*** convergence is proved using the spectral approximation theory for(non-selfadjoint)compact *** examples are presented for validation.

关键词： Steklov eigenvalues non-selfadjoint problems integral equations Nyström method spectral projection

An efficient and authenticated key establishment scheme based on fog computing for healthcare system

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Frontiers of Computer Science 2022年第4期16卷 173-184页

作者： Xinghua Li Ting Chen Qingfeng Cheng Jianfeng ma School of Cyber Engineering Xidian UniversityXi’an710071China

Because of its closeness to users,fog computing responds faster than cloud ***,it has been deployed to various applications,such as healthcare ***,to ensure the secure communication of the fog-based healthcare system,Jia et *** an authenticated key agreement ***,in view of the high computation cost existing in Jia et al.’s scheme,ma et *** an efficient one using elliptic curve *** this paper,we observe that both the two schemes may potentially risk ephemeral key compromise attacks and need ***,to overcome this potential risk,we propose a new authenticated scheme based on Jia et al.’s scheme using elliptic curve computational Diffie-Hellman hypothesis and hash ***,we provide provable security under the adopted adversarial model and ProVerif simulation,and also analyze the performance in terms of computation and communication costs by *** analysis results show that the improved scheme resists the common attacks,reduces computation overhead,and has a certain significance.

关键词： authenticated key establishment ephemeral key compromise attack fog-driven healthcare system elliptic curve cryptography provable security ProVerif simulation

倾斜衬底沉积法在金属衬底上外延生长YBCO薄膜

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功能材料 2004年第Z1期35卷 884-886页

作者：李美亚赵兴中 B.ma R.E.Koritala u.Balachandran 武汉大学物理科学与技术学院湖北武汉430072 武汉大学纳米科学与材料中心湖北武汉430072 Energy Technology Division Argonne National LaboratoryArgonneIL 60439USA

YBa2Cu3O7-x(YBCO)镀膜导体在电力等能源领域有巨大应用前景.利用倾斜衬底沉积法在无织构的金属衬底上生长了MgO双轴织构的模板层,在这一模板层上实现了双轴织构的YBCO薄膜的外延生长.这些膜的双轴织构用X射线极图分析、φ-扫描作了测定... 详细信息

YBa2Cu3O7-x(YBCO)镀膜导体在电力等能源领域有巨大应用前景.利用倾斜衬底沉积法在无织构的金属衬底上生长了MgO双轴织构的模板层,在这一模板层上实现了双轴织构的YBCO薄膜的外延生长.这些膜的双轴织构用X射线极图分析、φ-扫描作了测定,观测到了MgO[001]方向相对于衬底法线倾斜了31°.研究了不同缓冲层材料对YBCO外延生长的取向和双轴织构的影响,外延生长的高质量的YBCO薄膜的转变温度和临界电流密度分别达到了91K和5.5×105A/cm2的较高的值.

关键词： YBCO镀膜导体倾斜衬底沉积法外延生长

Image smoothing based on global sparsity decomposition and a variable parameter

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Computational Visual Media 2021年第4期7卷 483-497页

作者： Xiang ma Xuemei Li Yuanfeng Zhou Caiming Zhang Shandong university Jinan 250101China Shandong Co-Innovation Center of Future Intelligent Computing Yantai 264025China Digital Media Technology Key Lab of Shandong Province Jinan 250014China

Smoothing images,especially with rich texture,is an important problem in computer *** an ideal result is difficult due to complexity,irregularity,and anisotropicity of the ***,some properties are shared by the texture and the structure in an *** is a hard compromise to retain structure and simultaneously remove *** create an ideal algorithm for image smoothing,we face three *** images with rich textures,the smoothing effect should be *** should overcome inconsistency of smoothing results in different parts of the *** is necessary to create a method to evaluate the smoothing *** apply texture pre-removal based on global sparse decomposition with a variable smoothing parameter to solve the first two problems.A parametric surface constructed by an improved Bessel method is used to determine the smoothing *** evaluation measures:edge integrity rate,texture removal rate,and gradient value distribution are proposed to cope with the third *** use the alternating direction method of multipliers to complete the whole algorithm and obtain the *** show that our algorithm is better than existing algorithms both visually and *** also demonstrate our method’s ability in other applications such as clip-art compression artifact removal and content-aware image manipulation.

关键词： image smoothing texture removal global sparse decomposition Bessel method