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Combination Mechanism and Enhanced Visible-Light Photocatalytic Activity and Stability of CdS/g-C3N4 Heterojunctions

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Journal of Materials Science & Technology 2017年第1期33卷 30-38页

作者： Huanyan Xu Licheng Wu liguo Jin Kejia Wu School of Materials Science and Engineering Harbin University of Science and Technology Harbin 150040 China

In this study, CdS/g-C3N4 （CSCN） heterojunctions were in situ fabricated with a large amount of CdS nanoparticles anchored on g-C3N4 nanosheets, A wet chemical method was developed for the first time to determine the actual content of CdS in CSCN composites. X-ray diffraction （XRD）, Fourier transform infrared spectra （FFIR）, high-resolution transmission electron microscopy （HRTEM） and UV-vis diffuse reflectance spectra （DRS） were employed to characterize the composition, structure and optical prop- erty of CSCN composites. Based on the is0electric point （liP） analysis of g-C3N4, a conclusion was obtained on the combination mechanism between CdS nanoparticles and g-C3N4 nanosheets. The photocatalytic activity of CSCN composites was much better than those of individual CdS and g-C3N4 for the degrada- tion of azo dye Methyl Orange （MO） by 40 min adsorption in the dark followed by 15 min photocatalysis under visible light irradiation. After 5 cycles, CSCN composites still maintained high reactive activity with the MO degradation efficiency of 93.8%, exhibiting good photocatalytic stability. The Cd2~ concentration dissolved in the supernatant detected by atomic absorption spectroscopy （AAS） of CSCN composites was lower than that of pure CdS, implying that the photocorrosion of CdS could be suppressed via the combination with g-C3N4. Photoluminescence emission spectra （PL） results clearly revealed that the recombination of photogenerated electron-hole pairs in CSCN composites was effectively inhibited due to the formation of heterojunctions. Based on the band alignments of g-C3N4 and CdS, the possible photocatalvtic mechnism was discussed.

关键词： CdS/g-C3N4 Heterojunctions Photocatalytic stability Photocatalytic mechanism

Effect of Welding Technologies on Decreasing Welding Residual Stress of Francis Turbine Runner

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Journal of Materials Science & Technology 2010年第10期26卷 951-956页

作者： Shude Ji liguo Zhang Xuesong Liu Jianguo Yang School of Aerospace Engineering Shenyang Aerospace University Shenyang 110034 China State Key laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

On basis of the subsection welding and the local heating s reasonable technological parameters obtained by plane experiment,the welding residual stress field of some Francis turbine runner is regulated and *** the experimental plane with a thickness of 16 mm,the effect of subsection welding on decreasing welding residual stress of the prior welding section is obvious when the distance is less than 50 mm away from the end of latter welding *** the local heating,the best position,where the effect on decreasing the welding residual stress of plane is best,is 60 mm or so away from the edge of heating *** experimental results of runner show that the subsection welding can make the residual compressive stress engender in the blade dangerous area while the stress value is greatly influenced by the length of the welding section of blade *** local heating can further decrease the value of residual stress near blade outlet,while the local heating processed after heat treatment is better than that processed before heat treatment.

关键词： Blade Subsection welding Local heating Welding residual stress

Experimental Investigation on the Development Process of Large-Scale Low-Speed Stall Disturbance in Contra-Rotating Compressor

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Journal of Thermal Science 2020年第5期29卷 1282-1291页

作者： YUE Shaoyuan WANG Yan'gang WEI liguo WANG Hao School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China

In order to better understand the stall process of a contra-rotating compressor,the detailed characteristic and multi-channel unsteady pressure signals have been achieved by a special layout of high-frequency response pressure *** array consists of thirty-one high-frequency response dynamic sensors coupled with two optical fiber sensors that were installed on the compressor casing in the direction of circumferential and chordwise of the upstream and downstream of the contra-rotating rotors.A significant hysteresis loop during the stall-recovery process of the contra-rotating compressor was captured *** time series of unsteady signals when the compressor was working on the point of stall occurrence,the period of fully stall,and recovery stall were studied and *** show a large scale,and low-speed disturbance occurred abruptly at the leading-edge plane of the rear rotor and expands until it passes through both *** single stall cell occupied a circumferential range of 135° and moved in the direction of the rear rotor with an 8.3%shaft *** the mass flow rate dropped,the stall cell speed *** the stall recovery process,the rotational speed of disturbance suddenly increased from 7.5%to 18%and even increased to 47%just before the moment when flow recovered *** with the rear rotor,the front one dropped out unstable conditions earlier.

关键词： contra-rotating abrupt large scale stall

Exploring mission planning method for a team of carrier aircraft launching

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Chinese Journal of Aeronautics 2019年第5期32卷 1256-1267页

作者： Yu WU Yanyang WANG Xiangju QU liguo SUN College of Aerospace Engineering Chongqing University School of Aeronautic Science and Engineering Beihang University

High-level efficiency and safety are of great significance for improving the fighting capability of an aircraft carrier. One way to enhance efficiency and safety level is to organize the carrier aircraft into combat effectively. This paper studies the mission planning problem for a team of carrier aircraft launching, and a novel distributed mission planning architecture is proposed. The architecture is hierarchical and is comprised of four levels, namely, the input level, the coordination level,the path planning level and the execution level. Realistic constraints in each level of the distributed architecture, such as the vortex flow effect, the crowd effect and the motion of aircraft, are considered in the model. To solve this problem, a distributed path planning algorithm based on the asynchronous planning strategy is developed. The proposed Mission Planning Approach for Carrier Aircraft Launching(MPACAL) is validated using the setups of the Nimitz-class aircraft *** to the isolated planning architecture and the centralized planning architecture, the proposed distributed planning architecture has advantages in coordinating the launch tasks not only belonging to the same catapult but also when all different catapults are considered. The proposed MPACAL provides a modeling method for the flight deck operation on aircraft carrier.

关键词： Aircraft carrier Carrier aircraft Distributed planning architecture Mission planning Path planning

Time-varying linear control for tiltrotor aircraft

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Chinese Journal of Aeronautics 2018年第4期31卷 632-642页

作者： Jing ZHANG liguo SUN Xiangju QU Liuping WANG School of Aeronautic Science and Engineering Beihang University School of Electrical and Computer Engineering RMIT University

Tiltrotor aircraft have three flight modes： helicopter mode, airplane mode, and transition mode. A tiltrotor has characteristics of highly nonlinear, time-varying flight dynamics and inertial/-control couplings in its transition mode. It can transit from the helicopter mode to the airplane mode by tilting its nacelles, and an effective controller is crucial to accomplish tilting transition missions. Longitudinal dynamic characteristics of the tiltrotor are described by a nonlinear Lagrangeform model, which takes into account inertial/control couplings and aerodynamic *** commands for airspeed velocity and attitude in the transition mode are calculated dynamically by visiting a command library which is founded in advance by analyzing the flight envelope of the tiltrotor. A Time-Varying Linear（TVL） model is obtained using a Taylorexpansion based online linearization technique from the nonlinear model. Subsequently, based on an optimal control concept, an online optimization based control method with input constraints considered is proposed. To validate the proposed control method, three typical tilting transition missions are simulated using the nonlinear model of XV-15 tiltrotor aircraft. Simulation results show that the controller can be used to control the tiltrotor throughout its operating envelop which includes a transition flight, and can also deal with vertical gust disturbances.

关键词： Constrained optimal control Inertia/control couplings Tiltrotor aircraft Time-varying control Transition mode

Distinct Aeolian-fluvial Interbedded Landscapes in Three Watersheds of the Northern China

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Chinese Geographical Science 2021年第6期31卷 1070-1081页

作者： LI Xiaomei YAN Ping CAO liguo LIU Baoli School of Geography and Tourism Shaanxi Normal UniversityXi’an710119China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Academy of Disaster Reduction and Emergency Management Beijing Normal UniversityBeijing100875China College of Environment and Resources Fuzhou UniversityFuzhou350116China School of Geography and the Environment University of OxfordOxfordOX13QYUK

Due to the complex dynamic of aeolian and fluvial interacted processes behind the landform development,most of previous works started from classifying the types of landscape characterized by various aeolian and fluvial *** classifications are usually generalized based on large geomorphic data set abstracted from satellite images without field verification and dynamic field *** this study,we identified river banks in deserts as a unique geographical unit dominated by aeolian-fluvial *** distinct locations have been identified as representative study cases,which are in the Keriya River Basin in the west,the Mu Bulag River Basin in the middle and the Xar Moron River Basin in the east of the northern *** aeolian-fluvial interaction types were quantified based on site observation and measurement,topographic mapping and remote-sensing image *** morphological relationship between river channel and adjacent sand dunes areas were *** concluded that different channels are often associated with different distributions of riparian *** quantitative data enabled us to distinguish statistically four different types of landscape in aeolian-fluvial dominant environment,namely riverside dunes-straight channel,symmetrical interleaving dunes-meandering channel,river-island dunes-braiding channel,and grid-like dunes-anastomosing channel,aiming to provide compensational information to current aeolian-fluvial interaction *** angle of interaction between aeolian and fluvial systems,the windward and leeward sites of the bank,vegetation coverage and underlying landform determines the distribution,morphology,scale and direction of extension of the riparian *** results of the work study can provide a reference for study of aeolian-fluvial interactions at different spatial scales in arid region.

关键词： Sand dune-channel aeolian-fluvial interaction spatial distribution pattern type classification northern China

2-D NUMERICAL SIMULATION OF CRUSH BEDROCK RIVER

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Journal of Hydrodynamics 2004年第4期16卷 449-454页

作者： YINZe-gao ZHANGTu-qiao SUNDong-po liguo-qing DepartmentofCivilEngineering ZhejiangUniversityHangzhou310027China DepartmentofWaterConservancyEngineering NorthChinaInstituteofWaterConservancyandHydroelectricPowerZhengzhou450008China

In this paper, the erosion-resisting coefficient was introduced to computebed deformation in a crush bedrock river. In the case of crush bedrock, there has been no propercontrol equation to describe bed stability, which leads to difficulty in calculation of the beddeformation with conventional methods. The data from field survey were used to give thee-rosion-resisting capability with an appropriate coefficient. After the determination oflongitudinal distribution expressed by polynomial regression and transversal distribution expressedby normal distribution function, the plane distribution of erosion-resisting coefficient in a crushbedrock river was obtained. With the computational results from a 2-D horizontal flow mathematicalmodel, the erosion-resisting coefficient and controlling condition of local stability were employedto compute the values of bed deformation when riverbed is stable. The above method was applied in acase study, and the computational results of flow and bed deformations are in good a-greement withphysical model test data.

关键词： numerical simulation 2-D horizontal flow mathematical model (HFMM) erosion-resisting coefficient (ERC) bed deformation crush bedrock river

Prediction of Large Structure Welding Residual Stress by Similitude Principles

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Journal of Materials Science & Technology 2009年第6期25卷 861-864页

作者： Shude Ji liguo Zhang Xuesong Liu Jianguo Yang School of Aerospace Engineering Shenyang Institute of Aeronautical Engineering Shenyang 110034 China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

On basis of the similitude principles, the conception of virtual simulative component and the auxiliary value of welding residual stress, which is deduced by the welding conduction theory, the relation of the welding residual stress between the simulative component and the practical component was attained. In order to verify the correctness of the relation, the investigation was done from the view of the welding experiment and the numerical simulation about the simulative component and the practical component. The results show that the distribution of welding residual stress of the simulative component is the same as that of the practical component. The ratio of welding residual stress attained by the experiment or the simulation method between the practical runner and the simulative component was compared with the ratio obtained by the similitude principles. Moreover, the error is less than 10%. This provides a new idea to predict the welding stress distribution of large practical structure by the contractible physical model, which is important for the welding experiment and the numerical simulation.

关键词： Similitude principles Large welding structure Simulative components Welding residual stress

OH radicals generated by DC corona discharge for improving the pulsed discharge desulfuration efficiency

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Journal of Environmental Sciences 2004年第1期16卷 145-148页

作者： LIJie liguo-feng WUYan WANGNing-hui HUANGQiu-nan InstituteofElectrostaticsandSpecialPower DalianUniversityofTechnologyDalian116024China EducationInstituteofJilinProvince Changchun130021China

Positive DC corona discharge is formed with needle-plate electrode configuration, in which the water vapor is ejected though the needle points. The purpose is to increase the numbers of the water-based radicals, ionize the water molecule and improve the desulfuration efficiency of pulsed corona reactor. The water ions were determined by four stages molecular beam mass spectrometer and diagnose the water-based radicals by emission spectrograph. A conclusion on formation of ions and radicals with DC corona discharges can be drawn.

关键词： DC corona activator desulfuration