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Effects of the growing-maize canopy and irrigation characteristics on the ability to funnel sprinkler water

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Journal of Arid Land 2022年第7期14卷 787-810页

作者： zhu Zhongrui zhu Delan ge Maosheng LIU Changxin College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling 712100China Breeding and Seed Production of Agricultural Crops of Tashkent State Agrarian University Tashkent 100140Uzbekistan

Stemflow is vital for supplying water,fertilizer,and other crop essentials during sprinkler *** the spatial and temporal variations of crop stemflow and its influencing factors will be essential to preventing soil water and nutrient ion's migration to deeper layers,developing,and optimizing effective sprinkler irrigation *** on the two-year experimental data,we analyzed the variation patterns(stemflow amount,depth,rate,and funneling ratio)of maize stemflow during the growing season,and clarified its vertical distribution ***,effects of sprinkler irrigation and maize morphological parameters on stemflow were *** results showed that stemflow increased gradually as maize plant ***,stemflow was small at the pre-jointing stage and reached the maximum at the late filling *** upper canopy generated more stemflow than the lower canopy until the flare opening *** the tasseling stage,the middle canopy generated more stemflow than the other *** in canopy closure at different positions was the main factor contributing to the above *** sprinkler intensity increased,stemflow also ***,the effect of droplet size on stemflow was ***,when sprinkler intensity was less than or equal to 10 mm/h,stemflow was generated with increasing droplet *** contrast,if sprinkler intensity was greater than or equal to 20 mm/h,stemflow tended to decreased with increasing droplet *** with other morphological parameters,canopy closure significantly affected the generation of *** ratio was not significantly affected by plant *** on the results of different sprinkler intensities,we developed stemflow depth versus canopy closure and stemflow rate versus canopy closure power function regression models with a high predictive *** research findings will contribute to the understanding of the processes of stemflow inv

关键词： sprinkler intensity droplet diameter morphological parameter stemflow spatial-temporal variation

Effect of Sacrificial Anode Protection for Steel Pipe Piles at Dandong Port

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China Ocean Engineering 1998年第1期13卷 113-120页

作者： zhu, XC ge, Y ge, RG Nanjing Hydraul Res Inst Dept Mat & Struct Nanjing 210024 Peoples R China

The sacrificial anode protection system for the steel pipe piles of the 3rd berth of Dandong; wharf at Dandong port has operated for eight years. In this paper, the program design and the protection effect of the sacrificial anode protection system are presented. The results of various inspections show that the piles are protected very satisfactorily.

关键词： steel pipe pile corrosion sacrificial anode cathodic protection protection potential protection percentage

Catalytic Reduction of CO2 to CO via Reverse Water Gas Shift Reaction:Recent Advances in the Design of Active and Selective Supported Metal Catalysts

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Transactions of Tianjin University 2020年第3期26卷 172-187页

作者： Min zhu Qingfeng ge Xinli zhu Key Laboratory for Green Chemical Technology of Ministry of Education Tianjin UniversityTianjin 300350China Collaborative Innovation Center of Chemical Science and Engineering Tianjin UniversityTianjin 300350China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Department of Chemistry and Biochemistry Southern Illinois UniversityCarbondaleIL 62901USA

The catalytic conversion of CO2 to CO via a reverse water gas shift(RWGS)reaction followed by well-established synthesis gas conversion technologies may provide a potential approach to convert CO2 to valuable chemicals and ***,this reaction is mildly endothermic and competed by a strongly exothermic CO2 methanation reaction at low ***,the improvement in the low-temperature activities and selectivity of the RWGS reaction is a key challenge for catalyst *** reviewed recent advances in the design strategies of supported metal catalysts for enhancing the activity of CO2 conversion and its selectivity to *** strategies include varying support,tuning metal–support interactions,adding reducible transition metal oxide promoters,forming bimetallic alloys,adding alkali metals,and enveloping metal *** advances suggest that enhancing CO2 adsorption and facilitating CO desorption are key factors to enhance CO2 conversion and CO *** short review may provide insights into future RWGS catalyst designs and optimization.

关键词： Carbon dioxide Reverse water gas shift reaction Methanation Supported metal catalyst Mechanism

Application of novel force control strategies to enhance robotic abrasive belt grinding quality of aero-engine blades

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Chinese Journal of Aeronautics 2019年第10期32卷 2368-2382页

作者： xiaohu XU Dahu zhu Haiyang ZHANG Sijie YAN Han DING State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430074China Wuxi CRRC Times Intelligent Equipment Co. Ltd.Wuxi 214174China

Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and *** surface machining consistency,however,is difficult to be guaranteed in such a *** overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex *** signals are firstly obtained and transformed to force information with signal conditioning ***,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot ***,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the Z direction of the tool frame and the positon control law is used in the X direction of the tool ***,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding ***,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.

关键词： Gravity compensation Hybrid force-position control PI/PD control Robotic belt grinding Zero drift compensation

Characterization of halogenated DBPs and identification of new DBPs trihalomethanols in chlorine dioxide treated drinking water with multiple extractions

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Journal of Environmental Sciences 2017年第8期58卷 83-92页

作者： Jiarui Han Xiangru Zhang Jiaqi Liu xiaohu zhu Tingting Gong Environmental Engineering Program Department of Civil and Environmental Engineering The Hong Kong University of Science and Technology School of the Environment Nanjing University

Chlorine dioxide(ClO2) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen(TOX), a collective parameter for all halogenated DBPs, formed in ClO2-treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid–liquid extraction(LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO2-treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time *** the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols,were detected in the drinking water sample pretreated with multiple extractions; two of them,trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO2disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water.

关键词： Disinfection byproducts DBPs Chlorine dioxide treatment Multiple extractions Toxicity

ON STATE FEEDBACK AND POLE ASSIGNMENT OF THE SECOND ORDER COUPLED SINGULAR DISTRIBUTED PARAMETER SYSTEMS IN HILBERT SPACE

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Journal of Systems Science & Complexity 2011年第3期24卷 457-465页

作者： Zhaoqiang ge Guangtian zhu Dexing FENG Department of Applied Mathematics Xi'an Jiaotong University Xi'an 710049 China Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China.

State feedback and pole assignment of the second order coupled singular distributed parameter systems are discussed via functional analysis and operator theory in Hilbert space, in which infinite many poles are changed. The solutions of the problem and the constructive expression of the solutions are given by the generalized inverse of bounded linear operator. This research is theoretically important for studying the pole assignment and stabilization of the singular distributed parameter systems.

关键词： Second order coupled singular distributed parameter systems state feedback pole assignment.

Energy-efficient resource allocation for OFDMA relay systems with imperfect CSIT

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Science China(Information Sciences) 2015年第8期58卷 131-143页

作者： WANG XiaoMing ZHENG FuChun zhu PengCheng MENG Chao YOU xiaohu National Mobile Communications Research Laboratory Southeast University School of Systems Engineering University of Reading

In this paper, we propose an energy-efficient resource allocation scheme for the downlink of decodeand-forward relay-assisted orthogonal frequency division multiple access systems. The resource allocation is designed based on imperfect channel state information at the transmitter. We jointly optimize the power allocation, data rate allocation, and subcarrier allocation to maximize the system energy efficiency(EE). We formulate the EE problem as a probabilistic mixed non-convex optimization problem, in which the individual power constraints and the outage probability requirements are considered. An iterative algorithm based on bisection method is given to transform the optimization problem into a standard concave form. Also, we consider a proportional fairness design for the EE maximization problem. Simulation results illustrate the effectiveness of the proposed algorithm.

关键词： energy efficiency relay systems OFDMA decode-and-forward imperfect CSIT

Numerical Investigation of Flow Separation Control on a Highly Loaded Compressor Cascade by Plasma Aerodynamic Actuation

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Chinese Journal of Aeronautics 2012年第3期25卷 349-360页

作者： ZHAO xiaohu LI Yinghong WU Yun zhu Tao LI Yiwen Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038China

To discover the characteristic of separated flows and mechanism of plasma flow control on a highly loaded compressor cascade, numerical investigation is conducted. The simulation method is validated by oil flow visualization and pressure distribution. The loss coefficients, streamline patterns, and topology structure as well as vortex structure are analyzed. Results show that the numbers of singular points increase and three pairs of additional singular points of topology structure on solid surface generate with the increase of angle of attack, and the total pressure loss increases greatly. There are several principal vortices inside the cascade passage. The pressure side leg of horse-shoe vortex coexists within a specific region together with passage vortex, but finally merges into the latter. Corner vortex exists independently and does not evolve from the suction side leg of horse-shoe vortex. One pair of radial coupling-vortex exists near blade trailing edge and becomes the main part of backflow on the suction surface. Passage vortex interacts with the concentrated shedding vortex and they evolve into a large-scale vortex rotating in the direction opposite to passage vortex. The singular points and separation lines represent the basic separation feature of cascade passage. Plasma actuation has better effect at low freestream velocity, and the relative reductions of pitch-averaged total pressure loss coefficient with different actuation layouts of five and two pairs of electrodes are up to 30.8% and 26.7% while the angle of attack is 2~. Plasma actuation changes the local topology structure, but does not change the number relation of singular points. One pair of additional singular point of topology structure generates with plasma actuation and one more reattachment line appears, both of which break the separation line on the suction surface.

关键词： plasma aerodynamic actuation cascade oil flow visualization topology structure vortex singular point

Joint optimization of spectral efficiency and energy efficiency with low-precision ADCs in cell-free massive MIMO systems

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Science China(Information Sciences) 2022年第5期65卷 169-183页

作者： Han WANG Chang SUN Jiamin LI Pengcheng zhu Dongming WANG xiaohu YOU National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories

In cell-free massive multiple-input multiple-output(MIMO) systems, it is beneficial to apply low-precision analog-to-digital converters(ADCs) to reduce power consumption, hardware cost, and the load on backhaul link. However, low-precision ADCs will result in serious degradation in spectral efficiency(SE). It is important to achieve a good tradeoff between SE and energy efficiency(EE) for cell-free massive MIMO systems with low-precision ADCs. In this paper, we first derive the closed-form expressions of uplink achievable rates with maximal ratio combining(MRC) receiver and zero-forcing(ZF) receiver in cell-free massive MIMO systems. Then we analyze the EE model of cell-free massive MIMO systems. Based on the above analysis, the tradeoff between SE and EE is studied. Moreover, we propose two quantization bit allocation algorithms to optimize the SE and EE jointly from the perspective of multi-objective *** algorithm is based on the deep Q-network(DQN) and the other one is based on the non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ). The proposed algorithms provide more feasible solutions and achieve better system performance than equal quantization bit allocation algorithm. Numerical results verify the accuracy of the derived closed-form expressions and the effectiveness of the proposed optimization algorithms.

关键词： cell-free massive MIMO low-precision ADC spectral efficiency energy efficiency multi-objective optimization