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| 1 | Theory of multivariate compound extreme value distribution and its application to extreme sea state prediction显示文摘In this paper, a new type of distribution, multivariate compound extreme value distribution (MCEVD), is introduced by compounding a discrete distribution with a multivariate continuous distribution of extreme sea events. In its engineering application the number over certain threshold level per year is fitting to Poisson distribution and the corresponding extreme sea events are fitting to Nested Logistic distribution, then the Poisson-Nested logistic trivariate compound extreme value distribution (PNLTCED) is proposed to predict extreme wave heights, periods and wind speeds in Yellow Sea. The new model gives more stable and reasonable predicted results. | LIU Defu WANG Liping PANG Liang | 2006 | Chinese Science Bulletin2006，51，23： | 23 |
| 2 | Diel and seasonal variation of methane and carbon dioxide fluxes at Site Guojiaba, the Three Gorges Reservoir显示文摘In order to investigate the CH4and CO2fluxes across the water-gas interface and identify their controlling factors, four diel field campaigns and one monthly sampling campaign during June 2010–May 2011 were carried out at a site near the Three Gorges Dam,China. The averaged CH4and CO2fluxes across the air-water interface from the site were much less than those reported from reservoirs in tropic and temperate regions, and from the natural river channels of the Yangtze River. CH4Fluxes at the site were very low compared to most other reservoirs or natural lakes. One of the most important reasons may be due to the oxidation of CH4in the water column owing to the great water depth and high DO in water in the Three Gorges Reservoir. The averaged monthly CH4and CO2fluxes at the site during the observation year were 0.05 mg/(m2·hr) and 104.43 mg/(m2·hr) respectively with the maximum occurred in July 2010. The monthly CO2fluxes during the observation year were positively correlated to the surface water temperature, and negatively correlated to the air pressure and the surface water pH. The CO2flux showed a positive correlation with DOC to some extent, although not significantly, which indicated that allochthonous organic C was a major source of CO2and biogeochemical processes in this reservoir were C-limited. The significantly positive correlation between the reservoir outflow and the seasonal gas flux indicate the disturbance condition of the water body dominated the seasonal gas emission. | Shangbin Xiao Yuchun Wang Defu Liu Zhengjian Yang Dan Lei Cheng Zhang | 2013 | Journal of Environmental Sciences2013，25，10： | 20 |
| 3 | Poisson-Gumbel Mixed Compound Distribution and its application显示文摘With the development of offshore engineering, the joint probability study for extreme sea environments has been a subject of increasing interest for both mathematicians and engineers. However, the conventional multivariate probability distribution models do not describe the distribution of the occurrences of extreme sea states induced by typhoon, hurricane or winter storm, and thus fail to reflect the probability characteristics of sea environments in all the aspects. Extreme sea environments are typically to be found in storms like typhoon, and the occurrences of such storms in certain sea areas, varying from year to year, may be fitted to a discrete distribution. By compounding the discrete distribution with a bivariate continuous distribution of two extreme sea environments, a new kind of distribution-Bivariate Compound Extreme Value Distribution (BCEVD) is obtained in this note. This study proposes Poisson-Gum-bel Mixed Compound Distribution, one of the particular forms of BCEVD, and gives an | Defu Liu Shuqin Wen Liping Wang | 2002 | Chinese Science Bulletin2002，47，22： | 18 |
| 4 | Breast milk macronutrient composition and the associated factors in urban Chinese mothers显示文摘 | Yang Titi Zhang Yumei Ning Yibing You Lili Ma Defu Zheng Yingdong Yang Xiaoguang Li Wenjun Wang Junkuan Wang Peiyu | 2014 | Chinese Medical Journal2014，，9： | 17 |
| 5 | Disaster prevention design criteria for the estuarine cities:New Orleans and Shanghai The lesson from Hurricane Katrina显示文摘The accurate prediction of the typhoon (hurricane) induced extreme sea environments is very important for the coastal structure design in areas influenced by typhoon (hurricane). In 2005 Hurricane Katrina brought a severe catastrophe in New Orleans by combined effects of hurricane induced extreme sea environments and upper flood of the Mississippi River. Like the New Orleans City, Shanghai is located at the estuarine area of the Changjiang River and the combined effect of typhoon induced extreme sea environments, flood peak runoff from the Changjiang River coupled with the spring tide is the dominate factor for disaster prevention design criteria. The Poisson-nested logistic trivariate compound extreme value distribution (PNLTCEVD) is a new type of joint probability model which is proposed by compounding a discrete distribution (typhoon occurring frequency) into a continuous multivariate joint distribution (typhoon induced extreme events). The new model gives more reasonable predicted results for New Orleans and Shanghai disaster prevention design criteria. | LIU Defu SHI Hongda PANG Liang | 2006 | Acta Oceanologica Sinica2006，25，4： | 16 |
| 6 | An eco-environmental friendly operation: An effective method to mitigate the harmful blooms in the tributary bays of Three Gorges Reservoir显示文摘Harmful algal blooms, which frequently occur in different tributaries, have become a serious water quality problem of the Three Gorges Reservoir (TGR) since its initial filling. A three-year monitoring campaign from 2008 to 2010 was conducted to identify the controlling factors of algal blooms and effective preventive measures. The following results were obtained: 1) Layered and bidirectional currents, called intrusive density currents, dominate the tributary bays of the TGR year round; 2) continuously increasing water level can make the intruding density current shift from the middle to the surface, and surface intrusive water can reduce the surface water temperature and break the stable stratification of the tributary; 3) the appearing or fading away of algal blooms is closely associated with fluctuations in the TGR water level. Thus, the water level fluctuation patterns of different 'tide-types' may prevent the occurrence of algal blooms in the spring and summer, and the 'stair-type' tides may control autumn blooms during the impounding period. These methods were feasible and effective throughout the actual TGR's operation in 2009 2011. These patterns formed an eco-environmentally friendly operation (EEFO) to mitigate algal blooms. As an in situ treatment with easier operation and less negative impact and loss, compared with chemical and filter-feeding fish methods, the EEFO is currently considered as the most feasible remedial measure to remit the eco-environmental problems at the Three Gorges Dam (TGD). | YANG ZhengJian LIU DeFu JI DaoBin XIAO ShangBin HUANG YuLing MA Jun | 2013 | Science China(Technological Sciences)2013，56，6： | 14 |
| 7 | Impacts of water release operations on algal blooms in a tributary bay of Three Gorges Reservoir显示文摘Water release operation is crucial for water quality in large reservoirs such as Three Gorges Reservoir(TGR),because it determines the hydrodynamics and hence the self-purification capability.As algal blooms were often observed in some tributary bays of TGR during the release periods,high frequency field observations were carried out in a typical eutrophic tributary bay(Xiangxi River) from February 9 to May 10,2009.In this paper we assess the hydrodynamic behaviour,density stratification,and trophic status in this bay,respectively using a series of observations for flow,physical,chemical and biological parameters.Then,we analyze the effects of reservoir release operations on algal blooms using correlation analysis method.An empirical prognosis is concluded for the likelihood of algal bloom occurrence as a function of daily fluctuation of water level(DFWL) and water temperature.Our results indicate that during the release period,the algal bloom occurrences are closely tied to the DFWL in that if the ratio of DFWL to total water depth ranges from -10×10-4 to 0,the possibility of algal blooms may reach up to 70%,and if the ratio is less than -10×10-4,then that risk can be significantly reduced to less than 10%.This paper finally suggests that a wave-type water release operation should be beneficial in reducing bloom frequencies in the tributary water bodies,which is helpful for TGR water quality management,especially for the water release operation optimization. | ZHENG TieGang MAO JingQiao DAI HuiChao LIU DeFu | 2011 | Science China(Technological Sciences)2011，54，6： | 12 |
| 8 | Optimal guidance of extended trajectory shaping显示文摘To control missile's miss distance as well as terminal impact angle, by involving the timeto-go-nth power in the cost function, an extended optimal guidance law against a constant maneuvering target or a stationary target is proposed using the linear quadratic optimal control theory.An extended trajectory shaping guidance(ETSG) law is then proposed under the assumption that the missile-target relative velocity is constant and the line of sight angle is small. For a lag-free ETSG system, closed-form solutions for the missile's acceleration command are derived by the method of Schwartz inequality and linear simulations are performed to verify the closed-form results. Normalized adjoint systems for miss distance and terminal impact angle error are presented independently for stationary targets and constant maneuvering targets, respectively. Detailed discussions about the terminal misses and impact angle errors induced by terminal impact angle constraint, initial heading error, seeker zero position errors and target maneuvering, are performed. | Wang Hui Lin Defu Cheng Zhenxuan Wang Jiang | 2014 | Chinese Journal of Aeronautics2014，27，5： | 11 |
| 9 | Typhoon disaster zoning and prevention criteria——A double layer nested multi-objective probability model and its application显示文摘For prevention and mitigation of typhoon disasters in China, in this paper a double layer nested multi-objective probability model of typhoon disaster zoning and prevention criteria is proposed. The multivariate compound extreme value distribution (MCEVD) is used to predict the joint probability of seven typhoon characteristics and corresponding typhoon induced disasters. Predicted results can be used for both typhoon disaster zoning and corresponding prevention criteria along China coast. | LIU DeFu PANG Liang XIE BoTao WU YuanKang | 2008 | Science China(Technological Sciences)2008，51，7： | 10 |
| 10 | Analysis and improvement of missile three-loop autopilots显示文摘The non-minimum phase feature of tail-controlled missile airframes is analyzed.Three selection strategies for desired performance indexes are presented.An acceleration autopilot design methodology based on output feedback and optimization is proposed.Performance and robustness comparisons between the two-loop and classical three-loop topologies are made.Attempts to improve the classical three-loop topology are discussed.Despite the same open-loop structure,the classical three-loop autopilot shows distinct characteristics from a two-loop autopilot with PI compensator.Both the two-loop and three-loop topologies can stabilize a static unstable missile.However, the finite actuator resource is the crucial factor dominating autopilot function. | Lin Defu Fan Junfang Qi Zaikang Mou Yu | 2009 | Journal of Systems Engineering and Electronics2009，20，4： | 10 |
| 11 | Nucleation mechanisms of dynamic recrystallization in Inconel 625 superalloy deformed with different strain rates显示文摘The effects of strain rates on the hot working characteristics and nucleation mechanisms of dynamic recrystallization (DRX) were studied by optical microscopy and electron backscatter diffraction (EBSD) technique. Hot compression tests were conducted using a Gleeble-1500 simulator at a true strain of 0.7 in the temperature range of 1000 to 1150 °C and strain rate range of 0.01 to 10.00 s-1. It is found that the size and volume fraction of the DRX grains in hot-deformed Inconel 625 superalloy firstly decrease and then increase with increasing strain rate. Meanwhile, the nucleation mechanism of DRX is closely related to the deformation strain rate due to the deformation thermal effect. The discontinuous DRX (DDRX) with bulging of original grain boundaries is the primary nucleation mechanism of DRX, while the continuous DRX (CDRX) with progressive subgrain rotation acts as a secondary nucleation mechanism. The twinning formation can activate the nucleation of DRX. The effects of bulging of original grain boundaries and twinning formation are firstly gradually weakened and then strengthened with the increasing strain rate due to the deformation thermal effect. On the contrary, the effect of subgrain rotation is firstly gradually strengthened and then weakened with the increasing strain rate. | Guo, Qingmiao Li, Defu Peng, Haijian Guo, Shengli Hu, Jie Du, Peng | 2012 | Rare Metals2012，31，3： | 8 |
| 12 | Dynamic airspace sectorization via improved genetic algorithm显示文摘This paper deals with dynamic airspace sectorization (DAS) problem by an improved genetic algorithm (iGA). A graph model is first constructed that represents the airspace static structure. Then the DAS problem is formulated as a graph-partitioning problem to balance the sector workload under the premise of ensuring safety. In the iGA, multiple populations and hybrid coding are applied to determine the optimal sector number and airspace sectorization. The sector constraints are well satisfied by the improved genetic operators and protect zones. This method is validated by being applied to the airspace of North China in terms of three indexes, which are sector balancing index, coordination workload index and sector average flight time index. The improvement is obvious, as the sector balancing index is reduced by 16.5 %, the coordination workload index is reduced by 11.2 %, and the sector average flight time index is increased by 11.4 % during the peak-hour traffic. | Yangzhou Chen Hong Bi Defu Zhang Zhuoxi Song | 2013 | Journal of Modern Transportation2013，21，2： | 6 |
| 13 | A study on JA-and BTH-induced resistance of Rosa rugosa‘Plena’to powdery mildew(Sphaerotheca pannosa)显示文摘Different concentrations of jasmonic acid(JA)and benzothiadiazole(BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa(Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes(POD, PPO, and PAL) increased significantly.Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R.rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves. | Junxin Yan Yanan Deng Jia Yu Yongqiang Zhang Defu Chi | 2018 | Journal of Forestry Research2018，29，3： | 6 |
| 14 | Study on round rice straw bale wrapping silage technology and facilities显示文摘Specific to problems of the existing round bale wrapping machine in China,such as small application scope and failing to satisfy the wrapping demands of round bales of different specifications,a tumbler-type round bale wrapping machine based on wrapping silage with stretch film was designed.By theoretical analysis and preliminary experiments of the corresponding wrapping process,revolving speed of tumbler,speed ratio between tumbler and carrier rollers,and pre-load force of stretch film were determined as experimental factors,while wrapping time and consumption of stretch film per unit mass of round bale were determined as evaluation indexes.Furthermore,quadratic regression orthogonal rotational combination experimental design was adopted to carry out the wrapping experiment.The regression models were set up,and influencing rules of experimental factors on evaluation indexes were also analyzed.The optimal parameter combination scheme was revolving speed of tumbler of 31-32 r/min,speed ratio between tumbler and carrier rollers of 2.6,and pre-load force of stretch film of 20-22 N.Under such a circumstance,the corresponding wrapping time required was 37.7-38.9 s and consumption of stretch film per unit mass of round bale was 3.21-3.46 kg/t.The predicted values and the measured values of evaluation indexes basically coincided with each other and the relative error fell below 5%,which indicated that both the optimized regression models acquired through the wrapping experiment and the relevant parameter optimization results were reliable.To guarantee the quality of rice straw silage,the round bale should be wrapped by no less than five layers of stretch films through the utilization of the tumbler-type round bale wrapping machine.The study results could be used as references for research and development of the round bale wrapping machine. | Liqiao Li Defu Wang Xing Yang | 2018 | International Journal of Agricultural and Biological Engineering2018，11，4： | 5 |
| 15 | Dynamic airspace configuration method based on a weighted graph model显示文摘This paper proposes a new method for dynamic airspace configuration based on a weighted graph model. The method begins with the construction of an undirected graph for the given airspace, where the vertices represent those key points such as airports, waypoints, and the edges represent those air routes. Those vertices are used as the sites of Voronoi diagram, which divides the airspace into units called as cells. Then, aircraft counts of both each cell and of each air-route are computed. Thus, by assigning both the vertices and the edges with those aircraft counts, a weighted graph model comes into being. Accordingly the airspace configuration problem is described as a weighted graph partitioning problem. Then, the problem is solved by a graph partitioning algorithm, which is a mixture of general weighted graph cuts algorithm, an optimal dynamic load balancing algorithm and a heuristic algorithm. After the cuts algorithm partitions the model into sub-graphs, the load balancing algorithm together with the heuristic algorithm transfers aircraft counts to balance workload among sub-graphs. Lastly, airspace configuration is completed by determining the sector boundaries. The simulation result shows that the designed sectors satisfy not only workload balancing condition, but also the constraints such as convexity, connectivity, as well as minimum distance constraint. | Chen Yangzhou Zhang Defu | 2014 | Chinese Journal of Aeronautics2014，27，4： | 4 |
| 16 | Substance P and calcitonin gene-related peptide expression in dorsal root ganglia in sciatic nerve injury rats显示文摘The neuropeptides,substance P and calcitonin gene-related peptide,have been shown to be involved in pain transmission and repair of sciatic nerve injury.A model of sciatic nerve defect was prepared by dissecting the sciatic nerve at the middle,left femur in female Sprague Dawley rats.The two ends of the nerve were encased in a silica gel tube.L 5 dorsal root ganglia were harvested 7,14 and 28 days post sciatic nerve injury for immunohistochemical staining.Results showed that substance P and calcitonin gene-related peptide expression increased significantly in dorsal root ganglion of rats with sciatic nerve injury.This increase peaked at 7 days,declined at 14 days,and reduced to normal levels by 28 days post injury.The findings indicate that the neuropeptides,substance P and calcitonin gene- related peptide,mainly increased in the early stages after sciatic nerve injury. | Changma Fu Zongsheng Yin Defu Yu Zuhua Yang | 2013 | Neural Regeneration Research2013，8，33： | 4 |
| 17 | Study on the Breakwater Caisson as Oscillating Water Column Facility显示文摘The Oscillating Water Column(OWC) wave energy convertor with the advantage of its simple geometrical construction and excellent stability is widely employed.Recently,perforated breakwaters have been often used as they can effectively reduce the wave reflection from and wave forces acting on the structures.Considering the similarity between the compartment of perforated caisson and the air chamber of OWC wave energy convertor,a new perforated caisson of breakwater is designed in this paper.The ordinary caisson is modified by installing facilities similar to the air chamber of OWC converter,but here they are utilized to dissipate the wave energy inside the caisson.Such an arrangement improves the stability of the caisson and reduces the construction cost by using the compartment of perforated caisson like using an air chamber.This innovation has both academic significance and important engineering value.For a new type of caisson,reliability analysis of the structure is necessary.Linear potential flow theory is applied to calculate the horizontal wave force acting on the caisson.The calculated results are compared with experimental data,showing the feasibility of the method.The Importance Sampling Procedure(ISP) is used to analyse the reliability of this caisson breakwater. | HUANG Yan SHI Hongda LIU Defu LIU Zhen | 2010 | Journal of Ocean University of China2010，9，3： | 4 |
| 18 | Mechanisms of support failure and prevention measures under double-layer room mining gobs——A case study: Shigetai coal mine显示文摘In the practice of mining shallow buried ultra-close seams,support failure tends to occur during the process of longwall undermining beneath two layers of room mining goaf(TLRMG).In this paper,the factors causing support failure are summarized into geology and mining technology.Combining column lithology and composite beam theory,the key stratum of the rock strata is determined.A finite element numerical simulation is used to analyze the overlying load distribution rule of the main roof for different plane positions of the upper and lower room mining pillars.The tributary area theory(TAT)is adopted to analyze the vertical load distribution of each pillar,and dynamic models of coal pillar instability and main roof fracture are established.Through key block instability analysis,two critical moments are established,of which critical moment A has the greater dynamic load strength.Great economic losses and safety hazards are created by the dynamic load of the fracturing of the main roof.To reduce these negative effects,a method of pulling out supports is developed and two alternative measures for support failure prevention are proposed:reinforcing stope supports in conjunction with reducing mining height,or drilling ground holes to pre-split the main roof.Based on a comprehensive consideration of economic factors and the two categories of support failure causes,the method of reinforcing stope supports while reducing mining height was selected for use on the mining site. | Defu Zhu Shihao Tu Hongsheng Tu Zhenqian Yang | 2019 | International Journal of Mining Science and Technology2019，29，6： | 4 |
| 19 | Development and technical progress in large-scale circulating fluidized bed boiler in China显示文摘Circulating fluidized bed(CFB)boilers has realized the clean and efficient utilization of inferior coal like gangue and coal slime,high sulfur coal,anthracite,petroleum coke,oil shale and other resources.As a country with the largest amount of CFB boilers and the largest installed capacity in the world,China has 440100-600 MWe CFB boilers with a total capacity of 82.29 GWe,including 227 units of 135 MWe,95 units of300 MWe,and 24 supercritical units.The statistics of typical 100-300 MWe CFB boilers showed that the average number of unplanned shut-down was only 0.37 times per year,among which the 135 MWe was 0.26 times per year and 300 MWe was 0.46 times per ycai*.The auxiliary power ratio of some 300 MWe CFB boilers based on flow-pattern reconstruction can be reduced to about 4%,which is closed to the same level of pulverized coal(PC)boilers.This paper summarizes the development process and application status of China's large-scale CFB boilers,analyzes the characteristics and technical performance of the iconic units,and introduces solutions to the problems such as water wall wear and bottom ash cooling. | Zhong HUANG Lei DENG Defu CHE | 2020 | Frontiers in Energy2020，14，4： | 4 |
| 20 | Advanced forecasting of career choices for college students based on campus big data显示文摘 | Min NIE Lei YANG Jun SUN Han SU Hu XIA Defu LIAN Kai YAN | 2018 | Frontiers of Computer Science2018，12，3： | 3 |
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