After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang...After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang Chengzhong and Dai Chuanzeng at the CAS Institute of Modern Physics.From 1956 to 1958,I studied at Lebedev’s Institute of Physics under the Soviet Academy展开更多
Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration ...Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset.展开更多
Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provi...Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.展开更多
Experiments executed by author of the present article (period 1968-1992) showed that the magnetic spinorial particles (magnetic charges) are real structural components of atoms and substance and are immediate sources ...Experiments executed by author of the present article (period 1968-1992) showed that the magnetic spinorial particles (magnetic charges) are real structural components of atoms and substance and are immediate sources of all magnetic fields in Nature. Joint orbital currents of electric and magnetic charges within atomic shells are the natural sources of gravitational field which is a vortical electromagnetic field. The vector nature of the gravitational field, in essence, is analogous to the vortical magnetic field that allows entering in the physical representations of such States of the gravitational field as paragravitation and ferrogravitation. Physical masses (atoms, substance, etc.), which emit ferrogravitational field, are repelled by sources paragravitational field, for example, from Earth. It is a manifestation of the effect of levitation, which was discovered by the author of this article. The forces of the technical levitation, which are formed by technical ferrogravitational fields, can be used in transport, lifting and space technology, energy and many other areas of human activity. The main reason that the real magnetic charges were “buried alive” in modern theoretical physics is the conditions of their confinement in the structures of atoms and substance, which is radically different from the confinement of electrons. Very negative role is played here by erroneous electromagnetic concept Maxwell, in which the magnetic field was officially deprived of their own source: magnetic pole or magnetic charge.展开更多
In the past two years,many progresses are made in magnetospheric physics by using either the data of Double Star Program,Cluster and THEMIS missions,or by computer simulations. This paper briefly reviews these works b...In the past two years,many progresses are made in magnetospheric physics by using either the data of Double Star Program,Cluster and THEMIS missions,or by computer simulations. This paper briefly reviews these works based on papers selected from the 80 publications from April 2010 to April 2011.The subjects covered various sub-branches of magnetospheric physics,including geomagnetic storm,magnetospheric substorm,etc.展开更多
This article presents a further development of the hypotheses concerning the possibility of predicting (“tectonic”) earthquakes [1]. Those hypotheses are based on the conversion of all types of released energy into ...This article presents a further development of the hypotheses concerning the possibility of predicting (“tectonic”) earthquakes [1]. Those hypotheses are based on the conversion of all types of released energy into heat and active chemical substances. One of the important sources of this phenomenon is the release of the latent energy trapped and stored during the Earth’s accretion. The latent energy of primordial hydrogen and helium escaping from the Earth’s core and lower mantle causes degassing processes [2] [3]. This latent energy converts into totally different types of chemical, electromagnetic and thermal energies of active compounds that are responsible for the major endogenic terrestrial processes. The dominating theories in seismology and volcanology are that an earthquake results from a sudden slip of a tectonic fault and that only magma and the gases contained in magma supply the volcanic energy resulting in the conclusions that earthquakes and eruptions are unpredictable. Volcanic eruption is considered herein to be a special case of the earthquake-process in which earthquake hypocenters rise to the Earth’s surface. A possible solution is proposed ([1] and herein) based on the analyses of the physicochemical processes as participants in earthquake and eruption preparations (foreshocks - major shock - aftershocks - volcanic eruptions) and on the characteristic rates of reflection of these processes on the Earth’s surface. Influences of Sun-Moon-tides and volcanic (“harmonic”) tremors are analyzed from physical-chemical point of view. The case of the 1980 eruption of Mount St. Helens and the proposed monitoring of the recommended additional data provides a way of selecting a complex of reliable earthquake and volcanic eruption precursors.展开更多
In this paper,we introduce a new deep learning framework for discovering the phase-field models from existing image data.The new framework embraces the approximation power of physics informed neural networks(PINNs)and...In this paper,we introduce a new deep learning framework for discovering the phase-field models from existing image data.The new framework embraces the approximation power of physics informed neural networks(PINNs)and the computational efficiency of the pseudo-spectral methods,which we named pseudo-spectral PINN or SPINN.Unlike the baseline PINN,the pseudo-spectral PINN has several advantages.First of all,it requires less training data.A minimum of two temporal snapshots with uniform spatial resolution would be adequate.Secondly,it is computationally efficient,as the pseudo-spectral method is used for spatial discretization.Thirdly,it requires less trainable parameters compared with the baseline PINN,which significantly simplifies the training process and potentially assures fewer local minima or saddle points.We illustrate the effectiveness of pseudo-spectral PINN through several numerical examples.The newly proposed pseudo-spectral PINN is rather general,and it can be readily applied to discover other FDE-based models from image data.展开更多
[Objective] The research aimed to explore how to use the soil reasonably,prevent the degradation of soil fertility,maintain soil fertility,improve the ecological environment of paddy field and improve the soil product...[Objective] The research aimed to explore how to use the soil reasonably,prevent the degradation of soil fertility,maintain soil fertility,improve the ecological environment of paddy field and improve the soil productivity of paddy field from the cultivation aspect.[Method] Taking kenjiandao 10 as the material,the variation laws of root weight,soil physical and chemical characteristics,soil enzyme,straw decomposition rate,soil temperature,microorganism of rice under the planting patterns of water-saving pro...展开更多
Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography...Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field (EMHSF). Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields.展开更多
Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its format...Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its formation mechanism were obtained and discussed for thin-walled casting. The influences of magnetic field density on the filling ability, filling velocity and mold filling time have been studied. The differences in filling capability between gravity casting and casting under the traveling magnetic field have been compared. The results indicate that the mold filling ability of the gallium melt increases greatly under the condition of traveling magnetic field; the filling time is shortened from 18 s under gravity field to 3 s under the traveling magnetic field and average flow rate of the melt increases from 1.6 to 8.68 cm3/s; the change law of the cross-section morphology of the gallium melt during the mold filling is that at first, the cross-section area does not change, then it decreases gradually. When the front of the melt reaches the end of the mold cavity, the front melt will backfill the mold; the wider the width of mold cavity, the better the mold filling ability. The mold filling ability of gallium melt in mold with upper magnetic conductor is better than that without upper magnetic conductor.展开更多
The evolution of mining-induced stress field in longwall panel is closely related to the fracture field and the breaking characteristics of strata.Few laboratory experiments have been conducted to investigate the stre...The evolution of mining-induced stress field in longwall panel is closely related to the fracture field and the breaking characteristics of strata.Few laboratory experiments have been conducted to investigate the stress field.This study investigated its evolution by constructing a large-scale physical model according to the in situ conditions of the longwall panel.Theoretical analysis was used to reveal the mechanism of stress distribution in the overburden.The modelling results showed that:(1)The major principal stress field is arch-shaped,and the strata overlying both the solid zones and gob constitute a series of coordinated load-bearing structures.The stress increasing zone is like a macro stress arch.High stress is especially concentrated on both shoulders of the arch-shaped structure.The stress concentration of the solid zone in front of the gob is higher than the rear solid zone.(2)The characteristics of the vertical stress field in different regions are significantly different.Stress decreases in the zone above the gob and increases in solid zones on both sides of it.The mechanical analysis show that for a given stratum,the trajectories of principal stress are arch-shaped or inverselyarched,referred to as the‘‘principal stress arch’’,irrespective of its initial breaking or periodic breaking,and determines the fracture morphology.That is,the trajectories of tensile principal stress are inversely arched before the first breaking of the strata,and cause the breaking lines to resemble an inverted funnel.In case of periodic breaking,the breaking line forms an obtuse angle with the advancing direction of the panel.Good agreement was obtained between the results of physical modeling and the theoretical analysis.展开更多
A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and tempera...A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.展开更多
A field monitoring system was established in an active river bank landslide in the Three Gorges area, China, and a consecutive monitoring for about 5 years were conducted to understand the displacement characteristics...A field monitoring system was established in an active river bank landslide in the Three Gorges area, China, and a consecutive monitoring for about 5 years were conducted to understand the displacement characteristics of flexible piles and the surrounding soil. It was found that piles deformed elastically under reservoir operation, and the soil in front of piles was gradually separated from piles. The movement of the pile heads exceeded that of the soil between and behind piles. This phenomenon was further studied by a large-scale physical model test to gain insights into the pile-soil interaction. The displacement relationship between pile heads and the surrounding soil is in good agreement with the field data. The physical model test shows that the deformation process of pile-reinforced landslides can be divided into two stages: firstly, when the piles head movement exceeds soil movement, the soil arching is mainly affected by the deflection of the piles, the arches between and behind piles bent upwards;but when the soil movement exceeds piles head movement, the arches near the upslope and downslope bent downwards and upwards, respectively. Furthermore, the different deformation of two adjacent piles and the pile stiffness influenced the arch’s shape and formation;the flexible piles exhibit great coordinated deformation with the landslide, and caused the soil arch on the downslope.展开更多
Tribological properties of 150SN mineral oil and lubricating oils containing triethanolamine borate(TBE)with and without electromagnetic field impact were evaluated on a modified four-ball tribo-tester.The characteris...Tribological properties of 150SN mineral oil and lubricating oils containing triethanolamine borate(TBE)with and without electromagnetic field impact were evaluated on a modified four-ball tribo-tester.The characteristics of the worn surfaces were studied by scanning electronic microscopy(SEM),energy dispersive spectrometry(EDS)and X-ray photoelectron spectroscopy(XPS).Moreover,the tribological mechanisms are discussed from the viewpoint of physical effect and chemical effect.The results indicated that the friction coefficients and wear scar diameters(WSDs)lubricated by 150SN mineral oil under electromagnetic field were higher than those without electromagnetism impact.The WSDs of steel balls lubricated by TBE-doped oils under electromagnetic field were smaller than those obtained from non-electromagnetic field,but the friction coefficients were higher than those under non-electromagnetic field.A protective coating consists of wear particles could be formed on the frictional surface due to the physical effect of electromagnetic field on wear debris.The electromagnetic field could facilitate the interaction of elemental boron and nitrogen in TBE with metal interfaces,and contributes to forming tribo-chemical reaction film to reduce friction and wear.展开更多
Background:Dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces(CAF)field rations provided to military personnel deployed for training or operations.However,the high energy expend...Background:Dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces(CAF)field rations provided to military personnel deployed for training or operations.However,the high energy expenditures likely to occur under harsh environmental/metabolically challenging deployment conditions may not be adequately considered.This study examined the Ad libitum energy and nutrient intakes of CAF personnel(n=18)consuming field rations in a resting thermoneutral environment and during a day of standardized strenuous infantry activities at varying environmental temperatures.Methods:Dietary intake was assessed using a measured food intake/food waste method during the experimental treatment and for 6 h after treatment.Four treatments were administered in a randomized counterbalanced design:exercise(as standardized infantry activities)in the heat(30℃),exercise in the cold(–10℃),exercise in temperate thermoneutral(21℃)air temperatures and a resting(sedentary)trial(21℃).Results:The average Ad libitum consumption of field rations was 70%of the provided total energy(2776±99 kcal/8 h)during all treatments.Even with an acute challenge of increased energy expenditure and temperature stress in the simulated field conditions,participants’energy intakes(1985±747 kcal/8 h)under hot,cold and temperate treatments did not differ from energy intake during the sedentary condition(1920±640 kcal/8 h).Participants’energy intakes(1009±527 kcal/6 h)did not increase during the 6 h posttreatment period when the stresses of the strenuous physical activities and the harsh environmental temperatures had subsided.Conclusions:These results should be considered when planning the provision of field rations for CAF personnel expected to be engaged in strenuous physical activities with prolonged exposure to temperature extremes.展开更多
[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai durin...[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.展开更多
In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test ...In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test results,three-layer particleboard was designed.Particleboard face layers made with mixture of A,B,and C.The core layer made with D.The ratio of core layer to face layers is 50:50.Three-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were evaluated.The density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR analysis.The results showed that HVEF treatment intensity play a remarkable role in properties of particleboard.The particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and TS.Under HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),respectively.FTIR indicated that the surface activity of wood particles was increased electric field treatment.展开更多
文摘After graduating from the physics department of Qinghua University in 1952, I started working in the development of nuclear detectors (including cloud chambers and scintillometers) under the instruction of Profs. Yang Chengzhong and Dai Chuanzeng at the CAS Institute of Modern Physics.From 1956 to 1958,I studied at Lebedev’s Institute of Physics under the Soviet Academy
基金National Natural Science Foundation of China(U22422203,42030610,41975138,41975046,42075086,42275008)the High-level Science and Technology Journals Projects of Guangdong Province(214040990009)+1 种基金National Key Research and Development Program of China under Grant(2017YFC1501701,2017YFC1501703)Science and Technology Foundation of CAMS(2020KJ021)。
文摘Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset.
基金Project supported by the Key-Area Research and Development Program of Guang Dong Province,China(Grant No.2019B030330001)Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030008)+2 种基金the National Natural Science Foundation of China(Grant Nos.12074180,12005065,12022512,and 12035007)the Key Project of Science and Technology of Guangzhou(Grant Nos.201804020055 and 2019050001)the National Key Research and Development Program of China(Grant No.2016YFA0301800)。
文摘Nuclear physics,whose underling theory is described by quantum gauge field coupled with matter,is fundamentally important and yet is formidably challenge for simulation with classical computers.Quantum computing provides a perhaps transformative approach for studying and understanding nuclear physics.With rapid scaling-up of quantum processors as well as advances on quantum algorithms,the digital quantum simulation approach for simulating quantum gauge fields and nuclear physics has gained lots of attention.In this review,we aim to summarize recent efforts on solving nuclear physics with quantum computers.We first discuss a formulation of nuclear physics in the language of quantum computing.In particular,we review how quantum gauge fields(both Abelian and non-Abelian)and their coupling to matter field can be mapped and studied on a quantum computer.We then introduce related quantum algorithms for solving static properties and real-time evolution for quantum systems,and show their applications for a broad range of problems in nuclear physics,including simulation of lattice gauge field,solving nucleon and nuclear structures,quantum advantage for simulating scattering in quantum field theory,non-equilibrium dynamics,and so on.Finally,a short outlook on future work is given.
文摘Experiments executed by author of the present article (period 1968-1992) showed that the magnetic spinorial particles (magnetic charges) are real structural components of atoms and substance and are immediate sources of all magnetic fields in Nature. Joint orbital currents of electric and magnetic charges within atomic shells are the natural sources of gravitational field which is a vortical electromagnetic field. The vector nature of the gravitational field, in essence, is analogous to the vortical magnetic field that allows entering in the physical representations of such States of the gravitational field as paragravitation and ferrogravitation. Physical masses (atoms, substance, etc.), which emit ferrogravitational field, are repelled by sources paragravitational field, for example, from Earth. It is a manifestation of the effect of levitation, which was discovered by the author of this article. The forces of the technical levitation, which are formed by technical ferrogravitational fields, can be used in transport, lifting and space technology, energy and many other areas of human activity. The main reason that the real magnetic charges were “buried alive” in modern theoretical physics is the conditions of their confinement in the structures of atoms and substance, which is radically different from the confinement of electrons. Very negative role is played here by erroneous electromagnetic concept Maxwell, in which the magnetic field was officially deprived of their own source: magnetic pole or magnetic charge.
文摘In the past two years,many progresses are made in magnetospheric physics by using either the data of Double Star Program,Cluster and THEMIS missions,or by computer simulations. This paper briefly reviews these works based on papers selected from the 80 publications from April 2010 to April 2011.The subjects covered various sub-branches of magnetospheric physics,including geomagnetic storm,magnetospheric substorm,etc.
文摘This article presents a further development of the hypotheses concerning the possibility of predicting (“tectonic”) earthquakes [1]. Those hypotheses are based on the conversion of all types of released energy into heat and active chemical substances. One of the important sources of this phenomenon is the release of the latent energy trapped and stored during the Earth’s accretion. The latent energy of primordial hydrogen and helium escaping from the Earth’s core and lower mantle causes degassing processes [2] [3]. This latent energy converts into totally different types of chemical, electromagnetic and thermal energies of active compounds that are responsible for the major endogenic terrestrial processes. The dominating theories in seismology and volcanology are that an earthquake results from a sudden slip of a tectonic fault and that only magma and the gases contained in magma supply the volcanic energy resulting in the conclusions that earthquakes and eruptions are unpredictable. Volcanic eruption is considered herein to be a special case of the earthquake-process in which earthquake hypocenters rise to the Earth’s surface. A possible solution is proposed ([1] and herein) based on the analyses of the physicochemical processes as participants in earthquake and eruption preparations (foreshocks - major shock - aftershocks - volcanic eruptions) and on the characteristic rates of reflection of these processes on the Earth’s surface. Influences of Sun-Moon-tides and volcanic (“harmonic”) tremors are analyzed from physical-chemical point of view. The case of the 1980 eruption of Mount St. Helens and the proposed monitoring of the recommended additional data provides a way of selecting a complex of reliable earthquake and volcanic eruption precursors.
基金the support from NSF DMS-1816783NVIDIA Corporation for their donation of a Quadro P6000 GPU for conducting some of the numerical simulations in this paper.
文摘In this paper,we introduce a new deep learning framework for discovering the phase-field models from existing image data.The new framework embraces the approximation power of physics informed neural networks(PINNs)and the computational efficiency of the pseudo-spectral methods,which we named pseudo-spectral PINN or SPINN.Unlike the baseline PINN,the pseudo-spectral PINN has several advantages.First of all,it requires less training data.A minimum of two temporal snapshots with uniform spatial resolution would be adequate.Secondly,it is computationally efficient,as the pseudo-spectral method is used for spatial discretization.Thirdly,it requires less trainable parameters compared with the baseline PINN,which significantly simplifies the training process and potentially assures fewer local minima or saddle points.We illustrate the effectiveness of pseudo-spectral PINN through several numerical examples.The newly proposed pseudo-spectral PINN is rather general,and it can be readily applied to discover other FDE-based models from image data.
基金Supported by The National Project of Science & Technique Achievement Transformation(2008GB2B200089)Heilongjiang Nongken Zongju Science & Technological Key Project(HNKXI-01-06-01)Heilongjiang Nongken Zongju Science & Technological Development Project(NKKF06-10-1)~~
文摘[Objective] The research aimed to explore how to use the soil reasonably,prevent the degradation of soil fertility,maintain soil fertility,improve the ecological environment of paddy field and improve the soil productivity of paddy field from the cultivation aspect.[Method] Taking kenjiandao 10 as the material,the variation laws of root weight,soil physical and chemical characteristics,soil enzyme,straw decomposition rate,soil temperature,microorganism of rice under the planting patterns of water-saving pro...
基金supported by the National Science and Technology Major Project(No.2011ZX05020-006)
文摘Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field (EMHSF). Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields.
文摘Mold-filling process of thin-walled castings under the condition of traveling magnetic field has been studied by physical simulation method using gallium melt and fast speed photography. Flow morphology and its formation mechanism were obtained and discussed for thin-walled casting. The influences of magnetic field density on the filling ability, filling velocity and mold filling time have been studied. The differences in filling capability between gravity casting and casting under the traveling magnetic field have been compared. The results indicate that the mold filling ability of the gallium melt increases greatly under the condition of traveling magnetic field; the filling time is shortened from 18 s under gravity field to 3 s under the traveling magnetic field and average flow rate of the melt increases from 1.6 to 8.68 cm3/s; the change law of the cross-section morphology of the gallium melt during the mold filling is that at first, the cross-section area does not change, then it decreases gradually. When the front of the melt reaches the end of the mold cavity, the front melt will backfill the mold; the wider the width of mold cavity, the better the mold filling ability. The mold filling ability of gallium melt in mold with upper magnetic conductor is better than that without upper magnetic conductor.
基金This work was supported by the National Natural Science Foundation of China(NSFC,Grant No.51874175)the China Coal Technology&Engineering Group Foundation(Grant Nos.2018RC001,KJ-2018-TDKCZL-02).Comments from two anonymous reviewers and the editor are also greatly appreciated.
文摘The evolution of mining-induced stress field in longwall panel is closely related to the fracture field and the breaking characteristics of strata.Few laboratory experiments have been conducted to investigate the stress field.This study investigated its evolution by constructing a large-scale physical model according to the in situ conditions of the longwall panel.Theoretical analysis was used to reveal the mechanism of stress distribution in the overburden.The modelling results showed that:(1)The major principal stress field is arch-shaped,and the strata overlying both the solid zones and gob constitute a series of coordinated load-bearing structures.The stress increasing zone is like a macro stress arch.High stress is especially concentrated on both shoulders of the arch-shaped structure.The stress concentration of the solid zone in front of the gob is higher than the rear solid zone.(2)The characteristics of the vertical stress field in different regions are significantly different.Stress decreases in the zone above the gob and increases in solid zones on both sides of it.The mechanical analysis show that for a given stratum,the trajectories of principal stress are arch-shaped or inverselyarched,referred to as the‘‘principal stress arch’’,irrespective of its initial breaking or periodic breaking,and determines the fracture morphology.That is,the trajectories of tensile principal stress are inversely arched before the first breaking of the strata,and cause the breaking lines to resemble an inverted funnel.In case of periodic breaking,the breaking line forms an obtuse angle with the advancing direction of the panel.Good agreement was obtained between the results of physical modeling and the theoretical analysis.
文摘A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss.
基金the Key Program of National Natural Science Foundation of China(No.41630643)the National Key Research and Development Program of China(No.2017YFC1501302)+2 种基金the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(No.CUGCJ1701,1810491A26)the China Postdoctoral Science Foundation(No.2018M642952)the Postdoctoral International Exchange Program.
文摘A field monitoring system was established in an active river bank landslide in the Three Gorges area, China, and a consecutive monitoring for about 5 years were conducted to understand the displacement characteristics of flexible piles and the surrounding soil. It was found that piles deformed elastically under reservoir operation, and the soil in front of piles was gradually separated from piles. The movement of the pile heads exceeded that of the soil between and behind piles. This phenomenon was further studied by a large-scale physical model test to gain insights into the pile-soil interaction. The displacement relationship between pile heads and the surrounding soil is in good agreement with the field data. The physical model test shows that the deformation process of pile-reinforced landslides can be divided into two stages: firstly, when the piles head movement exceeds soil movement, the soil arching is mainly affected by the deflection of the piles, the arches between and behind piles bent upwards;but when the soil movement exceeds piles head movement, the arches near the upslope and downslope bent downwards and upwards, respectively. Furthermore, the different deformation of two adjacent piles and the pile stiffness influenced the arch’s shape and formation;the flexible piles exhibit great coordinated deformation with the landslide, and caused the soil arch on the downslope.
基金financial support provided by the Basic Science and Frontier Technology Research Project of Chongqing (CSTC, 2017jcyjAX0058)
文摘Tribological properties of 150SN mineral oil and lubricating oils containing triethanolamine borate(TBE)with and without electromagnetic field impact were evaluated on a modified four-ball tribo-tester.The characteristics of the worn surfaces were studied by scanning electronic microscopy(SEM),energy dispersive spectrometry(EDS)and X-ray photoelectron spectroscopy(XPS).Moreover,the tribological mechanisms are discussed from the viewpoint of physical effect and chemical effect.The results indicated that the friction coefficients and wear scar diameters(WSDs)lubricated by 150SN mineral oil under electromagnetic field were higher than those without electromagnetism impact.The WSDs of steel balls lubricated by TBE-doped oils under electromagnetic field were smaller than those obtained from non-electromagnetic field,but the friction coefficients were higher than those under non-electromagnetic field.A protective coating consists of wear particles could be formed on the frictional surface due to the physical effect of electromagnetic field on wear debris.The electromagnetic field could facilitate the interaction of elemental boron and nitrogen in TBE with metal interfaces,and contributes to forming tribo-chemical reaction film to reduce friction and wear.
基金funded in part by Defence Research&Development Canada(DRDC)approved by the Canadian Forces Surgeon General’s Health Research Programthe Department of National Defence(DND)policy。
文摘Background:Dietary Reference Intakes are used to guide the energy intake of the Canadian Armed Forces(CAF)field rations provided to military personnel deployed for training or operations.However,the high energy expenditures likely to occur under harsh environmental/metabolically challenging deployment conditions may not be adequately considered.This study examined the Ad libitum energy and nutrient intakes of CAF personnel(n=18)consuming field rations in a resting thermoneutral environment and during a day of standardized strenuous infantry activities at varying environmental temperatures.Methods:Dietary intake was assessed using a measured food intake/food waste method during the experimental treatment and for 6 h after treatment.Four treatments were administered in a randomized counterbalanced design:exercise(as standardized infantry activities)in the heat(30℃),exercise in the cold(–10℃),exercise in temperate thermoneutral(21℃)air temperatures and a resting(sedentary)trial(21℃).Results:The average Ad libitum consumption of field rations was 70%of the provided total energy(2776±99 kcal/8 h)during all treatments.Even with an acute challenge of increased energy expenditure and temperature stress in the simulated field conditions,participants’energy intakes(1985±747 kcal/8 h)under hot,cold and temperate treatments did not differ from energy intake during the sedentary condition(1920±640 kcal/8 h).Participants’energy intakes(1009±527 kcal/6 h)did not increase during the 6 h posttreatment period when the stresses of the strenuous physical activities and the harsh environmental temperatures had subsided.Conclusions:These results should be considered when planning the provision of field rations for CAF personnel expected to be engaged in strenuous physical activities with prolonged exposure to temperature extremes.
文摘[Objective] The research aimed to understand role of the forecast data about physical quantity field in precipitation forecast.[Method] By contrasting forecast and actual situation of the precipitation in Yantai during 2-3 July and 12-15 September,2011,advantages and disadvantages of the different numerical forecast models (Japan fax chart,European center,MM5,Grapes and T639) were analyzed.[Result] MICAPS system could provide live situation of the physical quantity field,but couldn't provide the future evolution situation.Japan fax chart,European center,MM5,Grapes and T639 could provide future evolution situation of the physical quantity field.[Conclusion] The contrasts and analyses on forecast situations of the physical quantity fields in many precipitation processes showed that evolutions of the vertical velocity,temperature dew point difference,relative humidity and wind field at the different heights could improve forecast accuracy of the precipitation in Yantai.
基金The Authors acknowledge funding support by the National Key R&D Program of China(2017YFC0703501)The authors wish to acknowledge the National Natural Science Foundation of China(Grant No.32071700).
文摘In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test results,three-layer particleboard was designed.Particleboard face layers made with mixture of A,B,and C.The core layer made with D.The ratio of core layer to face layers is 50:50.Three-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were evaluated.The density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR analysis.The results showed that HVEF treatment intensity play a remarkable role in properties of particleboard.The particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and TS.Under HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),respectively.FTIR indicated that the surface activity of wood particles was increased electric field treatment.