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Water sorption on coal:effects of oxygen-containing function groups and pore structure

International Journal of Coal Science & Technology 2021年第5期8卷 983-1002页

作者： ang liu Shimin liu Peng liu Kai Wang Department of Energy and Mineral Engineering G3 Center and Energy InstituteThe Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China School of Emergency Management and Safety Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Coal-water interactions have profound influences on gas extraction from coal and coal *** measurements on three coals using X-ray photoelectron spectroscopy(XPS),low-temperature nitrogen adsorption and dynamic water vapor sorption(DVS)were conducted.A mechanism-based isotherm model was proposed to estimate the water vapor uptake at various relative humidities,which is well validated with the DVS *** validated isotherm model of sorption was further used to derive the isosteric heat of water vapor *** specific surface area of coal pores is not the determining parameter that controls water vapor sorption at least during the primary adsorption *** degree dominates the primary adsorption,and which togethering with the cumulative pore volume determine the secondary *** temperature has limited effects on primary adsorption *** isosteric heat of water adsorption decreases as water vapor uptake increases,which is found to be close to the latent heat of bulk water condensation at higher relative *** results confirmed that the primary adsorption is controlled by the stronger bonding energy while the interaction energy between water molecules during secondary adsorption stage is relatively ***,the thermodynamics of coal-water interactions are complicated since the internal bonding interactions within the coal are disrupted at the same time as new bonding interactions take place within water *** has a shrinkage/swelling colloidal structure with moisture loss/gain and it may exhibit collapse behavior with some collapses irreversible as a function of relative humidity,which further plays a significant role in determining moisture retention.

关键词： Water vapor Isotherm Surface oxidation Pore collapse Isosteric heat of adsorption

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Theoretical analysis of influencing factors on resistance in the process of gas migration in coal seams

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International Journal of Mining Science and Technology 2017年第2期27卷 315-319页

作者： Wang Kai liu ang Zhou Aitao School of Resource and Safety Engineering China University of Mining and Technology State Key Laboratory of Coal Resource and Mine Safety School of Resources and Safety Engineering

Inspired by previous resistance models for porous media, a resistance expression of gas migration within coal seams based on the ideal matchstick geometry, combined with the Darcy equation and the modified Poiseuille equation is proposed. The resistance to gas migration is generally dynamic because of the variations in adsorption swelling and matrix shrinkage. Due to the limitations of experimental conditions,only a theoretical expression of resistance to gas migration in coal is deduced, and the impacts of tortuosity, effective stress and pore pressure on the resistance are then considered. To validate the proposed expression, previous data from other researchers are adopted for the history matching exercise, and the agreement between the two is good.

关键词： Porous media Gas Resistance Tortuosity Effective stress Pore pressure

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Mechanical criterion for coal and gas outburst:a perspective from multiphysics coupling

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International Journal of Coal Science & Technology 2021年第6期8卷 1423-1435页

作者： Ting liu Baiquan Lin Xuehai Fu ang liu School of Safety Engineering China University of Mining&TechnologyXuzhou 221116China Key Laboratory of CBM Resources and Dynamic Accumulation Process China University of Mining&TechnologyXuzhou 221008China Department of Energy and Mineral Engineering G3 Center and EMS Energy InstituteThe Pennsylvania State UniversityUniversity ParkPAUSA

Although a series of hypotheses have been proposed,the mechanism underlying coal and gas outburst remains *** the low-index outbursts encountered in mining practice,we attempt to explore this mechanism using a multiphysics coupling model considering the effects of coal strength and gas mass transfer on *** on force analysis of coal ahead of the heading face,a risk identification index C_(m)and a critical criterion(C_(m)≥1)of coal instability are *** to this criterion,the driving force of an outburst consists of stress and gas pressure gradients along the heading direction of the roadway,whereas resistance depends on the shear and tensile strengths of the *** results show that outburst risk decreases slightly,followed by a rapid increase,with increasing vertical stress,whereas it decreases with increasing coal strength and increases with gas pressure *** the response surface method,a coupled multi-factor model for the risk identification index is *** results indicate strong interactions among the controlling ***,the critical values of the factors corresponding to outburst change depending on the environment of the coal seams,rather than being *** the buried depth of a coal seam increases,the critical values of gas pressure and coal strength decrease slightly,followed by a rapid *** to its controlling factors,outburst can be divided into stress-dominated,coal-strength-dominated,gas-pressure-dominated,and multi-factor compound *** on this classification,a classified control method is proposed to enable more targeted outburst prevention.

关键词： Coal and gas outburst Critical criterion Multiphysics coupling Response surface method

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Inversion of Evaporation and Water Vapor Transport Using HY-2 Multi-Sensor Data

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Journal of Ocean University of China 2020年第1期19卷 13-22页

作者： liu Dong’ang SUN Jian GUAN Changlong Physical Oceanography Laboratory/CIMST Ocean University of China and Qingdao National Laboratory for Marine Science and Technology

HY-2 satellite is the first marine dynamic environment satellite of *** this study,global evaporation and water vapor transport of the global sea surface are calculated on the basis of HY-2 multi-sensor data from April 1 to 30,*** algorithm of evaporation and water vapor transport is discussed in detail,and results are compared with other reanalysis *** sea surface temperature of HY-2 is in good agreement with the ARGO buoy *** clusters are shown in the scatter plot of HY-2 and OAFlux evaporation due to the uneven global distribution of *** improve the calculation accuracy,we compared the different parameterization schemes and adopted the method of calibrating HY-2 precipitation data by SSM/I and Global Precipitation Climatology Project(GPCP)*** calculating the water vapor transport,the adjustment scheme is proposed to match the balance of the water cycle for data in the low latitudes.

关键词： HY-2 multi-sensor data inversion evaporation water vapor transport data calibration

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Secure state estimation for cyber-physical systems with unknown input sliding mode observer

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Control Theory and Technology 2024年第2期22卷 244-253页

作者： Panpan Zhang Yuwei Ren Yixian Fang ang liu School of Information Science and Engineering Shandong Normal UniversityJinan250358ShandongChina School of Information Engineering Shandong Management UniversityJinan250357ShandongChina

In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of the system. This paper proposes a secure state estimation for multi-input and multi-output continuous-time linear cyber-physical systems with sparse actuator and sensor attacks. First, for sparse sensor attacks, we propose an adaptive switching mechanism to mitigate the impact of sparse sensor attacks by filtering out their attack modes. Second, an unknown input sliding mode observer is designed to not only observe the system states, sensor attack signals, and measurement noise present in the system but also counteract the effects of sparse actuator attacks through an unknown input matrix. Finally, for the design of an unknown input sliding mode state observer, the feasibility of the observing system is demonstrated by means of Lyapunov functions. Additionally, simulation experiments are conducted to show the effectiveness of this method.

关键词： Sparse attacks Cyber-physical systems Unknown input sliding mode Secure state estimation Adaptive switching mechanism

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Anisotropic coal permeability and its stress sensitivity

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International Journal of Mining Science and Technology 2019年第3期29卷 507-511页

作者： Zhiming Yan Kai Wang Jie Zang Chuan Wang ang liu Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources China University of Mining & TechnologyBeijing 100083China Yangquan Coal Industry (Group) Co. LTDYangquan 045000China Faculty of Resource & Safety Engineering China University of Mining & TechnologyBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining & TechnologyBeijing 100083China

This paper focuses on anisotropy of coal permeability and its stress *** blocks were taken from Xinjing Coal Mine in Yangquan Coal *** cores were then drilled along the strike,dip,and vertical *** permeabilities were measured with respect to stress by using a self-developed coal permeability measurement *** used samples exhibited significant permeability *** permeability along the strike direction was greatest among the three directions,the permeability along the vertical direction was the smallest,and the permeability along the dip direction was between the other two *** sensitivity of coal permeability to stress was transversely *** stress sensitivity coefficient was greater along the horizontal directions than along the vertical *** permeability exhibited anisotropic stress sensitivity due to anisotropy in Young’s modulus and *** results obtained in this study are useful for optimizing the arrangement of pre-drainage boreholes.

关键词： Coal permeability Anisotropy Stress sensitivity Gas drainage Experiment

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Oxidation Modification of Polyacrylonitrile-Based Carbon Fiber and Its Electro-Chemical Performance as Marine Electrode for Electric Field Test

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Journal of Ocean University of China 2020年第2期19卷 361-368页

作者： ZAI Xuerong liu ang TIAN Yuhua CHAI Fanggang FU Yubin College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical *** surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact *** voltammetry and Tafel curves have been used to study its electro-chemical *** identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-*** self noise level is 1.07 nV√Hz^(1/2)@1 *** electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its *** electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday *** advantages of the carbon fiber electric field electrode will make it have potential application prospect.

关键词： carbon fiber electrode electro-chemical oxidation modification electro-chemical performance electric field response electric field test

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Design of an electronic label for logistics temperature monitoring with low power consumption

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Optoelectronics Letters 2019年第1期15卷 16-20页

作者： liu Zhi-ang ZHang Quan School of Electrical Engineering and Automation Harbin Institute of Technology College of Electronic Information and Automation Tianjin University of Science and Technology

There are many problems when traditional temperature sensing radio frequency identification(RFID) tags are applied to logistics temperature monitoring, such as inconvenient data reading, large power consumption, and low bandwidth. Therefore, a low-dissipation electronic tag is designed in this paper to solve the above problems. The electronic tag and the portable temperature recorder were placed in the same position in the same refrigeration unit, and the temperature of the same space was recorded at the same time. The data measured by the designed electronic tag was used as the measured value, and the data measured by the portable temperature recorder was used as the standard value. The correlation coefficient between the two was calculated to be 0.866 9, the root mean square error(RMSE) was 0.796 7 ℃, and the average relative deviation(ARD) was 16.21%. Therefore, the electronic tag designed in this study can meet the requirements of users for temperature monitoring and recording. The temperature control switch designed in this study can disconnect the power supply to single chip microcomputer(SCM) and other modules when the temperature is in the range of normal threshold, so that the power consumption is further reduced and the cost is reduced. The results of this study laid a foundation for the development of low-cost and easy-to-use temperature monitoring technology in the logistics process.

关键词： Design label temperature

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QBIoT:A Quantum Blockchain Framework for IoT with an Improved Proof-of-Authority Consensus Algorithm and a Public-Key Quantum Signature

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Computers, Materials & Continua 2024年第7期80卷 1727-1751页

作者： ang liu Qing Zhang Shengwei Xu Huamin Feng Xiu-bo Chen Wen liu Network and Information Management Division Beijing Electronic Science and Technology InstituteBeijing100070China Department of Cyberspace Security Beijing Electronic Science and Technology InstituteBeijing100070China Information Security Institute Beijing Electronic Science and Technology InstituteBeijing100070China General Office Beijing Electronic Science and Technology InstituteBeijing100070China Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing100876China

The Internet of Things(IoT)is a network system that connects physical devices through the Internet,allowing them to ***,IoT has become an integral part of our lives,offering convenience and smart ***,the growing number of IoT devices has brought about a corresponding increase in cybersecurity threats,such as device vulnerabilities,data privacy concerns,and network *** blockchain technology with IoT has proven to be a promising approach to enhance IoT ***,the emergence of quantum computing poses a significant challenge to the security of traditional classical cryptography used in blockchain,potentially exposing it to quantum *** support the growth of the IoT industry,mitigate quantum threats,and safeguard IoT data,this study proposes a robust blockchain solution for IoT that incorporates both classical and post-quantum security ***,we present the Quantum-Enhanced Blockchain Architecture for IoT(QBIoT)to ensure secure data sharing and integrity ***,we propose an improved Proof of Authority consensus algorithm called“Proof of Authority with Random Election”(PoARE),implemented within QBIoT for leader selection and new block ***,we develop a publickey quantum signature protocol for transaction verification in the ***,a comprehensive security analysis of QBIoT demonstrates its resilience against cyber threats from both classical and quantum *** summary,this research introduces an innovative quantum-enhanced blockchain solution to address quantum security concernswithin the realmof *** proposedQBIoT framework contributes to the ongoing development of quantum blockchain technology and offers valuable insights for future research on IoT security.

关键词： IoT quantum blockchain public-key quantum signature quantum hash function

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Real-time GNSS precise point positioning with smartphones for vehicle navigation

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Satellite Navigation 2022年第3期3卷 140-161,I0004页

作者： Zishen Li Liang Wang Ningbo Wang Ran Li ang liu Aerospace Information Research Institute(AIR) Chinese Academy of Sciences(CAS)Beijing100094China School of Electronic Electrical and Communicating EngineeringUniversity of Chinese Academy of Sciences19A Yuquan RoadShijingshan DistrictBeijing100049China

The availability of raw Global Navigation Satellite System(GNSS)measurements from Android smart devices gives new possibilities for precise positioning solutions,e.g.,Precise Point Positioning(PPP).However,the accuracy of the PPP with smart devices currently is a few meters due to the poor quality of the raw GNSS measurements in a kinematic scenario and in urban environments,particularly when the smart devices are placed inside *** promote the application of GNSS PPP for land vehicle navigation with smart devices,this contribution studies the real-time PPP with *** data quality analysis and positioning performance validation,two vehicle-based kinematic positioning tests were carried out using two Huawei Mate30 smartphones and two Huawei P40 smartphones with different installation modes:the vehicle-roof mode with smartphones mounted on the top roof outside the vehicle,and the dashboard mode with smartphones stabilized on the dashboard inside the *** realize high accuracy positioning,we proposed a real-time smartphone PPP method with the data processing strategies adapted for smart *** results show that the real-time PPP can achieve the horizontal positioning accuracy of about 1–1.5 m in terms of root-mean-square and better than 2.5 m at the 95th percentile for the vehicle-based kinematic positioning with the experimental smartphones mounted on the dashboard inside the vehicle,which is the real scenario in vehicle navigation.

关键词： Global Navigation Satellite System Smartphone positioning Precise point positioning Raw GNSS measurements Land vehicle navigation

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