Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by ...Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by tuning miscut angles(θ)from 0°to 7°off the(1010)direction of sapphire(0002)substrate.On flat sapphire surfaces,the growth undergoes a typical three-dimensional(3D)growth mode due to the random nucleation on wide substrate terraces,as evidenced by the hillock morphology and high dislocation densities.As the miscut angle increases toθ=5°,the terrace width of sapphire substrate is comparable to the distance between neighboring nuclei,and consequently,the nucleation is guided by terrace edges,which energetically facilitates the growth mode transition into the desirable two-dimensional(2D)coherent growth.Consequently,the mean surface roughness decreases to only 0.62 nm,accompanied by a significant reduction in screw and edge dislocations to 0.16×10^(7) cm^(-2)and 3.58×10^(9) cm^(-2),respectively.However,the further increment of miscut angles toθ=7°shrink the terrace width less than nucleation distance,and the step-bunching growth mode is dominant.In this circumstance,the misfit strain is released in the initial growth stage,resulting in surface morphology degradation and increased dislocation densities.展开更多
AFM scanning images of the surface of a PTCDA/p-Si specimen used in an organic/inorganic photodetector show that PTCDA grows in island shapes that are poorly distributed, with each island shaped like a round hillock. ...AFM scanning images of the surface of a PTCDA/p-Si specimen used in an organic/inorganic photodetector show that PTCDA grows in island shapes that are poorly distributed, with each island shaped like a round hillock. The images also show that there exist enormous defects in the PTCDA layer due to pedestal sites and other defects that appear when Si atoms shift transversely, and that the bonding condition is satisfied by the action of atom suspension bonding at the surface of the Si substrate. We infer the growth mode of PTCDA deposited onto p-Si substrates as follows. First,PTCDA molecules assemble at the defects to form three-dimensional island-like PTCDA crystal nuclei, and then by the action of delocalized big π bonding, two adjacent layers of PTCDA molecules overlap to some extent and finally island-like structures form. The PTCDA molecules and Si substrate combine by a process of the combination of benzene rings with Si atoms at the defects and of acid anhydride radicals with Si atoms at the perfect fraction of the surface. In the course of combination, although the structure of the benzene rings does not change, the chemical reaction of acid anhydt＇ide radicals and Si occurs to break off the C=O bond in the acid anhydride, and then C-Si-O and silicon oxide might be produced.展开更多
The relationship between the spatial position of the diamond seed and growth mode is investigated with an enclosedtype holder for single-crystal diamond growth using the microwave plasma chemical vapor deposition epit...The relationship between the spatial position of the diamond seed and growth mode is investigated with an enclosedtype holder for single-crystal diamond growth using the microwave plasma chemical vapor deposition epitaxial method.The results demonstrate that there are three main regions by varying the spatial position of the seed.Due to the plasma concentration occurring at the seed edge,a larger depth is beneficial to transfer the plasma to the holder surface and suppress the polycrystalline diamond rim around the seed edge.However,the plasma density at the edge decreases drastically when the depth is too large,resulting in the growth of a vicinal grain plane and the reduction of surface area.By adopting an appropriate spatial location,the size of single-crystal diamond can be increased from 7 mm×7 mm×0.35 mm to8.6 mm×8.6 mm×2.8 mm without the polycrystalline diamond rim.展开更多
The process of the multilayer growth of Pt on Pt(111)is studied by using a Monte Carlo model with realisticphysical parameters.The effects of the substrate temperature,the ES barrier,and the deposition rate on the gro...The process of the multilayer growth of Pt on Pt(111)is studied by using a Monte Carlo model with realisticphysical parameters.The effects of the substrate temperature,the ES barrier,and the deposition rate on the growthmode have been investigated.Gradual transitions of the surface roughness from oscillatory to non-oscillatory behaviorand then back to oscillatory behavior are observed while increasing the substrate temperature from 270 K to 620 K.Itis found that the growth mode depends strongly on ES barrier over the whole temperatures and the deposition rate ofatoms effectively affects the growth mode.The simulation results are consistent with many experimental observationsfor homoexpitaxy on a Pt(111)substrate.展开更多
Using liquid quenching technique,the change of growth mode of graphite in cast iron melt was analysed.Based on the interface structure theory of crystal growth,the concept of multiplication of spiral growth steps was ...Using liquid quenching technique,the change of growth mode of graphite in cast iron melt was analysed.Based on the interface structure theory of crystal growth,the concept of multiplication of spiral growth steps was advanced and two basic multiplication models were given.It was proposed that multiplication of spiral steps is responsible for the change of growth mode of graphite in cast iron melt.The modifying elements such as Ce promote multiplication of spiral steps,which is regarded as the core of modification.Origination of screw dislocation and branch of the sector blocks in radius direction,both of which are essential to spheroidization of graphite in the melt,are caused by multiplication of spiral steps:and so is thickening of graphite plates.展开更多
Thin and thick films of iron phthalocyanine （FePc） molecules are deposited on a Ag （110） surface. The nature of the FePc growth and the interaction with the substrate have been studied by X-ray photoelectron spect...Thin and thick films of iron phthalocyanine （FePc） molecules are deposited on a Ag （110） surface. The nature of the FePc growth and the interaction with the substrate have been studied by X-ray photoelectron spectroscopy （XPS）. All of the core level spectra exhibit rigid shifts towards lower binding energies following the deposition of the organic films, each by a different magnitude. A greater change and a larger shift in the Fe2p level as compared to Cls core level reveals that the adsorbate interacts with the substrate mainly via the Fe atom, located at the center of the molecule. An increase/decrease in the intensity of C1 s/Ag3d level is found to be exponentially linked to the overlayer molecular coverage. Finally, the so- called growth/decay curve indicates that FePc thin films initially develop following the FM growth mode and then transform to SK mode, resulting in 3D island aggregation.展开更多
A realistic kinetic Monte Carlo （KMC） simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu（100） surfaces at room temperature. ...A realistic kinetic Monte Carlo （KMC） simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu（100） surfaces at room temperature. The effects of mass transport between interlayers and edge diffusion of atoms along the islands are included in the simulation model, and the surface roughness and the layer distribution versus total coverage are calculated. Speeially, the simulation model reveals the transition of growth mode with coverage and the difference between the Ni heteroepitaxy on Cu（100） and the Ni homoepitaxy on Ni（100）. Through comparison of KMC simulation with the real scanning tunneling microscopy （STM） experiments, the Ehrlich-Schwoebel （ES） barrier Ees is estimated to be 0.18±0.02 eV for Ni/Cu（100） system while 0.28 eV for Ni/Ni（100）. The simulation also shows that the growth mode depends strongly on the thickness of thin film and the surface temperature, and the critical thickness of growth mode transition is dependent on the growth condition such as surface temperature and deposition flux as well.展开更多
How to obtain fast-growth errors, which is comparable to the actual forecast growth error, is a crucial problem in ensemble forecast （EF）. The method, Breeding of Growth Modes （BGM）, which has been used to generat...How to obtain fast-growth errors, which is comparable to the actual forecast growth error, is a crucial problem in ensemble forecast （EF）. The method, Breeding of Growth Modes （BGM）, which has been used to generate perturbations for medium-range EF at NCEP, simulates the development of fast-growth errors in the analysis cycle, and is a reasonable choice in capturing growing errors modes, especially for extreme weather by BGM. An ideal supercell storm, simulated by Weather Research Forecast model （WRF）, occurred in central Oklahoma on 20 May 1977. This simulation was used to study the application of BGM methods in the meso-scale strong convective Ensemble Prediction System （EPS）. We compared the forecasting skills of EPS by different pertubation methods, like Monte-Carlo and BGM. The results show that the ensemble average forecast based on Monte-Carlo with statistics meaning is superior to the single-deterministic prediction, but a less dynamic process of the method leads to a smaller spread than expected. The fast-growth errors of BGM are comparable to the actual short-range forecast error and a more appropriate ensemble spread. Considering evaluation indexes and scores, the forecast skills of EPS by BGM is higher than Monte-Carlo＇s. Furthermore, various breeding cycles have different effects on precipitation and non-precipitation fields, confirmation of reasonable cycles need consider balance between variables.展开更多
The growth mode of 3,4,9,10-perylenetetra-carboxylic dianhydride(PTCDA) deposited on p-Si substrates can be deduced by X-ray Photoemission Spectroscopy(XPS). The spectrum and fine spectrum at the surface of specimen a...The growth mode of 3,4,9,10-perylenetetra-carboxylic dianhydride(PTCDA) deposited on p-Si substrates can be deduced by X-ray Photoemission Spectroscopy(XPS). The spectrum and fine spectrum at the surface of specimen are studied. Firstly, PTCDA molecules assemble at the defects to form lots of three-dimensional island-like PTCDA crystal nucleuses, and then by the action of delocalized big π bond, two adjacent layers of PTCDA molecules overlap to some extent and finally island-like structure forms. PTCDA molecules of benzene ring combine with Si atoms at the defects, and that of acid anhydride radicals combine with Si atoms at the perfect fraction of the surface. In the course of combination, although the structure of benzene ring doesn't change, the chemical reaction of acid anhydride radicals and Si occurs to break off C=O bond in acid anhydride, and then C-Si-O and silicon oxide might be produced.展开更多
It is an urgent and important economic work in the moment and the next period for China to realize the transformation of economic growth mode. Relatively, there must be certain basic conditions. This article makes ela...It is an urgent and important economic work in the moment and the next period for China to realize the transformation of economic growth mode. Relatively, there must be certain basic conditions. This article makes elaboration of the basic conditions, which accelerate the change of Shaanxi＇s economic growth mode from government angle, and proposes countermeasures for it, according to Shaanxi＇s situation and the requirement of scientific development concept, in order to provide basis for the government＇s economic growth transformation.展开更多
China will face some structural challenges in the next five years. Global interest rates will likely rise. The labor force in China is shrinldng. Property and infrastructure investments face constraints as growth is ...China will face some structural challenges in the next five years. Global interest rates will likely rise. The labor force in China is shrinldng. Property and infrastructure investments face constraints as growth is driven. Financial risks have reached alarming levels.展开更多
That the Chinese economy has been burgeoning for nearly 30 years is an irrefutable fact.However,this robust growth has been achieved amidst accusations of"extensive"development and"low-efficiency"....That the Chinese economy has been burgeoning for nearly 30 years is an irrefutable fact.However,this robust growth has been achieved amidst accusations of"extensive"development and"low-efficiency".Many scholars believe that low-priced labour is pivotal to China’s rapid growth.Even so,we find it hard to explain why China has been able to achieve sustained growth while so many countries with even lower labour costs remain trapped in poverty The following article offers a new perspective upon this paradox.展开更多
Presently China mainly relies on the low cost of production factors and introducing advanced foreign technology to create an international competitive edge.Thepresent foreign trade growth mode,which is charaterized of...Presently China mainly relies on the low cost of production factors and introducing advanced foreign technology to create an international competitive edge.Thepresent foreign trade growth mode,which is charaterized of quantitative expansion,labor-intensive and low prices,low e ciency,unsustained,is facing lots ofdifficulties.The problems such as the worsening terms of trade,the huge trade surplus,too much dependence on foreign trade,the rising prices of production factors,difficulties in the introduction of high technology,excessive consumption of resources,environmental pressures exacerbated the situations.Therefore,China mustadopt effective measures into a sustained and high efficiency foreign trade growth mode,which is supposed to be described as optimization of export commoditystructure,market diversification,mainly relying on independent innovation and independent brands,promoting trade with science and technology,rationaliztion ofindustrial structure,focusing on high added value.展开更多
A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF dis...A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF displays a linear geometry or a geometry of overlapping of linear and arcuate segments and a growth and development process of the breakdown segment\|by\|segment, connection segment\|by\|segment and propagation gradually (northeastward migration of the northeast tip, southwestward growth of the southwest tip). The formation of the Altun fault began in the middle or upper Carboniferous. It was characteristic of the sinistral strike\|slip\|thrust before Eocene, of the thrust\|sinistral strike\|slip during Oligocene—Miocene, and of the normal slip, and thrust\|sinistral strike\|slip simultaneously since Miocene.展开更多
This paper presents an extension of a displacement discontinuity method with cracktip elements （a boundary element method） proposed by the author for fatigue crack growth analysis in plane elastic media under mixed-...This paper presents an extension of a displacement discontinuity method with cracktip elements （a boundary element method） proposed by the author for fatigue crack growth analysis in plane elastic media under mixed-mode conditions. The boundary element method consists of the non-singular displacement discontinuity elements presented by Crouch and Starfield and the crack-tip displacement discontinuity elements due to the author. In the boundary element implementation the left or right crack-tip element is placed locally at the corresponding left or right crack tip on top of the non-singular displacement discontinuity elements that cover the entire crack surface and the other boundaries. Crack growth is simulated with an incremental crack extension analysis based on the maximum circumferential stress criterion. In the numerical simulation, for each increment of crack extension, remeshing of existing boundaries is not required because of an intrinsic feature of the numerical approach. Crack growth is modeled by adding new boundary elements on the incremental crack extension to the previous crack boundaries. At the same time, the element characteristics of some related elements are adjusted according to the manner in which the boundary element method is implemented. As an example, the fatigue growth process of cracks emanating from a circular hole in a plane elastic plate is simulated using the numerical simulation approach.展开更多
A convection-allowing ensemble forecast experiment on a squall line was conducted based on the breeding growth mode （BGM）. Meanwhile, the probability matched mean （PMM） and neighborhood ensemble probability （NEP...A convection-allowing ensemble forecast experiment on a squall line was conducted based on the breeding growth mode （BGM）. Meanwhile, the probability matched mean （PMM） and neighborhood ensemble probability （NEP） methods were used to optimize the associated precipitation forecast. The ensemble forecast predicted the precipita- tion tendency accurately, which was closer to the observation than in the control forecast. For heavy rainfall, the pre- cipitation center produced by the ensemble forecast was also better. The Fractions Skill Score （FSS） results indicated that the ensemble mean was skillful in light rainfall, while the PMM produced better probability distribution of pre- cipitation for heavy rainfall. Preliminary results demonstrated that convection-allowing ensemble forecast could im- prove precipitation forecast skill through providing valuable probability forecasts. It is necessary to employ new methods, such as the PMM and NEP, to generate precipitation probability forecasts. Nonetheless, the lack of spread and the overprediction of precipitation by the ensemble members are still problems that need to be solved.展开更多
The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours incl...The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous—Cenozoic and Plio-Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-Tibet plateau. With southward propagation of the thrust sequence and continued uplift of the plateau, the NE tip of the Altun fault moved in a NE direction, while the SW tip grew in a SW direction.展开更多
An analytical expression of the peeling mode in the near separatrix region of diverted tokamak plasma is derived. It is shown that in diverted plasmas both with single and double X points, though the perturbed potenti...An analytical expression of the peeling mode in the near separatrix region of diverted tokamak plasma is derived. It is shown that in diverted plasmas both with single and double X points, though the perturbed potential energy of the unstable peeling mode tends to be large, its growth rate becomes very small due to the even larger kinetic energy. Compared to some recent studies that give qualitatively correct results about this growth rate, our result is directly related with the diverted equilibrium quantities suitable for application to realistic experiments.展开更多
In this paper, the economic growth factors are classified into two types and three kinds by the growth rate function of Solow. Based on their contribution, the economic growth mode is classified into three types and e...In this paper, the economic growth factors are classified into two types and three kinds by the growth rate function of Solow. Based on their contribution, the economic growth mode is classified into three types and eight kinds. The case analysis of the classfication of economic growth mode is given. Finally, the paper gives the economic growth function which describes the principle of interaction among economic growth factors.展开更多
The development mode of mid-small cities in northern Jiangsu is analyzed on the Growth Pole theory.Depending on scales,endowment of resources,geographical positions,and industrial advantages of mil-small cities,we can...The development mode of mid-small cities in northern Jiangsu is analyzed on the Growth Pole theory.Depending on scales,endowment of resources,geographical positions,and industrial advantages of mil-small cities,we can divide the development mode of those mid-small cities within this context into five types:development through integration into big cities;independent development;resource-dependent development;single industry development;and mixed industry development.展开更多
基金Project supported by the National Key Research and Development Program of China (Grant No.2022YFB3605403)the National Natural Science Foundation of China (Grant Nos.62234007,62241407,62293521,62304238,62241407,U21A20503,and U21A2071)+2 种基金the Key-Area Research and Development Program of Guangdong Province,China (Grant No.2020B010174002)the Cultivation Project for Youth Teachers in Jiangsu ProvinceJiangsu Funding Program for Excellent Postdoctoral Talent。
文摘Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by tuning miscut angles(θ)from 0°to 7°off the(1010)direction of sapphire(0002)substrate.On flat sapphire surfaces,the growth undergoes a typical three-dimensional(3D)growth mode due to the random nucleation on wide substrate terraces,as evidenced by the hillock morphology and high dislocation densities.As the miscut angle increases toθ=5°,the terrace width of sapphire substrate is comparable to the distance between neighboring nuclei,and consequently,the nucleation is guided by terrace edges,which energetically facilitates the growth mode transition into the desirable two-dimensional(2D)coherent growth.Consequently,the mean surface roughness decreases to only 0.62 nm,accompanied by a significant reduction in screw and edge dislocations to 0.16×10^(7) cm^(-2)and 3.58×10^(9) cm^(-2),respectively.However,the further increment of miscut angles toθ=7°shrink the terrace width less than nucleation distance,and the step-bunching growth mode is dominant.In this circumstance,the misfit strain is released in the initial growth stage,resulting in surface morphology degradation and increased dislocation densities.
文摘AFM scanning images of the surface of a PTCDA/p-Si specimen used in an organic/inorganic photodetector show that PTCDA grows in island shapes that are poorly distributed, with each island shaped like a round hillock. The images also show that there exist enormous defects in the PTCDA layer due to pedestal sites and other defects that appear when Si atoms shift transversely, and that the bonding condition is satisfied by the action of atom suspension bonding at the surface of the Si substrate. We infer the growth mode of PTCDA deposited onto p-Si substrates as follows. First,PTCDA molecules assemble at the defects to form three-dimensional island-like PTCDA crystal nuclei, and then by the action of delocalized big π bonding, two adjacent layers of PTCDA molecules overlap to some extent and finally island-like structures form. The PTCDA molecules and Si substrate combine by a process of the combination of benzene rings with Si atoms at the defects and of acid anhydride radicals with Si atoms at the perfect fraction of the surface. In the course of combination, although the structure of the benzene rings does not change, the chemical reaction of acid anhydt＇ide radicals and Si occurs to break off the C=O bond in the acid anhydride, and then C-Si-O and silicon oxide might be produced.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2020B0101690001)。
文摘The relationship between the spatial position of the diamond seed and growth mode is investigated with an enclosedtype holder for single-crystal diamond growth using the microwave plasma chemical vapor deposition epitaxial method.The results demonstrate that there are three main regions by varying the spatial position of the seed.Due to the plasma concentration occurring at the seed edge,a larger depth is beneficial to transfer the plasma to the holder surface and suppress the polycrystalline diamond rim around the seed edge.However,the plasma density at the edge decreases drastically when the depth is too large,resulting in the growth of a vicinal grain plane and the reduction of surface area.By adopting an appropriate spatial location,the size of single-crystal diamond can be increased from 7 mm×7 mm×0.35 mm to8.6 mm×8.6 mm×2.8 mm without the polycrystalline diamond rim.
基金the Natural Science Foundation for Young Scientists of Zhejiang Province of China under Grant No.RC02069
文摘The process of the multilayer growth of Pt on Pt(111)is studied by using a Monte Carlo model with realisticphysical parameters.The effects of the substrate temperature,the ES barrier,and the deposition rate on the growthmode have been investigated.Gradual transitions of the surface roughness from oscillatory to non-oscillatory behaviorand then back to oscillatory behavior are observed while increasing the substrate temperature from 270 K to 620 K.Itis found that the growth mode depends strongly on ES barrier over the whole temperatures and the deposition rate ofatoms effectively affects the growth mode.The simulation results are consistent with many experimental observationsfor homoexpitaxy on a Pt(111)substrate.
文摘Using liquid quenching technique,the change of growth mode of graphite in cast iron melt was analysed.Based on the interface structure theory of crystal growth,the concept of multiplication of spiral growth steps was advanced and two basic multiplication models were given.It was proposed that multiplication of spiral steps is responsible for the change of growth mode of graphite in cast iron melt.The modifying elements such as Ce promote multiplication of spiral steps,which is regarded as the core of modification.Origination of screw dislocation and branch of the sector blocks in radius direction,both of which are essential to spheroidization of graphite in the melt,are caused by multiplication of spiral steps:and so is thickening of graphite plates.
基金Project supported by the National Natural Science Foundation of China (Grants Nos.10974172,10774129,and 61106131)the Fundamental Research Funds for the Central Universities
文摘Thin and thick films of iron phthalocyanine （FePc） molecules are deposited on a Ag （110） surface. The nature of the FePc growth and the interaction with the substrate have been studied by X-ray photoelectron spectroscopy （XPS）. All of the core level spectra exhibit rigid shifts towards lower binding energies following the deposition of the organic films, each by a different magnitude. A greater change and a larger shift in the Fe2p level as compared to Cls core level reveals that the adsorbate interacts with the substrate mainly via the Fe atom, located at the center of the molecule. An increase/decrease in the intensity of C1 s/Ag3d level is found to be exponentially linked to the overlayer molecular coverage. Finally, the so- called growth/decay curve indicates that FePc thin films initially develop following the FM growth mode and then transform to SK mode, resulting in 3D island aggregation.
基金the State Key Basic Research Development Project of China under Grant No.2006CB708612the Key Project of Science and Technology of Zhejiang Province under Grant No.2007C21120
文摘A realistic kinetic Monte Carlo （KMC） simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu（100） surfaces at room temperature. The effects of mass transport between interlayers and edge diffusion of atoms along the islands are included in the simulation model, and the surface roughness and the layer distribution versus total coverage are calculated. Speeially, the simulation model reveals the transition of growth mode with coverage and the difference between the Ni heteroepitaxy on Cu（100） and the Ni homoepitaxy on Ni（100）. Through comparison of KMC simulation with the real scanning tunneling microscopy （STM） experiments, the Ehrlich-Schwoebel （ES） barrier Ees is estimated to be 0.18±0.02 eV for Ni/Cu（100） system while 0.28 eV for Ni/Ni（100）. The simulation also shows that the growth mode depends strongly on the thickness of thin film and the surface temperature, and the critical thickness of growth mode transition is dependent on the growth condition such as surface temperature and deposition flux as well.
基金supported jointly by the Nature Science Foundation of China (Project No:40875068)Public-Welfare Meteorological Research Foundation (ProjectNo:GYHY200806029)
文摘How to obtain fast-growth errors, which is comparable to the actual forecast growth error, is a crucial problem in ensemble forecast （EF）. The method, Breeding of Growth Modes （BGM）, which has been used to generate perturbations for medium-range EF at NCEP, simulates the development of fast-growth errors in the analysis cycle, and is a reasonable choice in capturing growing errors modes, especially for extreme weather by BGM. An ideal supercell storm, simulated by Weather Research Forecast model （WRF）, occurred in central Oklahoma on 20 May 1977. This simulation was used to study the application of BGM methods in the meso-scale strong convective Ensemble Prediction System （EPS）. We compared the forecasting skills of EPS by different pertubation methods, like Monte-Carlo and BGM. The results show that the ensemble average forecast based on Monte-Carlo with statistics meaning is superior to the single-deterministic prediction, but a less dynamic process of the method leads to a smaller spread than expected. The fast-growth errors of BGM are comparable to the actual short-range forecast error and a more appropriate ensemble spread. Considering evaluation indexes and scores, the forecast skills of EPS by BGM is higher than Monte-Carlo＇s. Furthermore, various breeding cycles have different effects on precipitation and non-precipitation fields, confirmation of reasonable cycles need consider balance between variables.
文摘The growth mode of 3,4,9,10-perylenetetra-carboxylic dianhydride(PTCDA) deposited on p-Si substrates can be deduced by X-ray Photoemission Spectroscopy(XPS). The spectrum and fine spectrum at the surface of specimen are studied. Firstly, PTCDA molecules assemble at the defects to form lots of three-dimensional island-like PTCDA crystal nucleuses, and then by the action of delocalized big π bond, two adjacent layers of PTCDA molecules overlap to some extent and finally island-like structure forms. PTCDA molecules of benzene ring combine with Si atoms at the defects, and that of acid anhydride radicals combine with Si atoms at the perfect fraction of the surface. In the course of combination, although the structure of benzene ring doesn't change, the chemical reaction of acid anhydride radicals and Si occurs to break off C=O bond in acid anhydride, and then C-Si-O and silicon oxide might be produced.
文摘It is an urgent and important economic work in the moment and the next period for China to realize the transformation of economic growth mode. Relatively, there must be certain basic conditions. This article makes elaboration of the basic conditions, which accelerate the change of Shaanxi＇s economic growth mode from government angle, and proposes countermeasures for it, according to Shaanxi＇s situation and the requirement of scientific development concept, in order to provide basis for the government＇s economic growth transformation.
文摘China will face some structural challenges in the next five years. Global interest rates will likely rise. The labor force in China is shrinldng. Property and infrastructure investments face constraints as growth is driven. Financial risks have reached alarming levels.
文摘That the Chinese economy has been burgeoning for nearly 30 years is an irrefutable fact.However,this robust growth has been achieved amidst accusations of"extensive"development and"low-efficiency".Many scholars believe that low-priced labour is pivotal to China’s rapid growth.Even so,we find it hard to explain why China has been able to achieve sustained growth while so many countries with even lower labour costs remain trapped in poverty The following article offers a new perspective upon this paradox.
文摘Presently China mainly relies on the low cost of production factors and introducing advanced foreign technology to create an international competitive edge.Thepresent foreign trade growth mode,which is charaterized of quantitative expansion,labor-intensive and low prices,low e ciency,unsustained,is facing lots ofdifficulties.The problems such as the worsening terms of trade,the huge trade surplus,too much dependence on foreign trade,the rising prices of production factors,difficulties in the introduction of high technology,excessive consumption of resources,environmental pressures exacerbated the situations.Therefore,China mustadopt effective measures into a sustained and high efficiency foreign trade growth mode,which is supposed to be described as optimization of export commoditystructure,market diversification,mainly relying on independent innovation and independent brands,promoting trade with science and technology,rationaliztion ofindustrial structure,focusing on high added value.
文摘A set of ENE\|trending fault which locates in the rigid Tarim massif and flexible Qilian massif in the same dynamic system of the uplift of the Qinghai—Tibetan plateau is referred to as the Altun Fault (ALF). ALF displays a linear geometry or a geometry of overlapping of linear and arcuate segments and a growth and development process of the breakdown segment\|by\|segment, connection segment\|by\|segment and propagation gradually (northeastward migration of the northeast tip, southwestward growth of the southwest tip). The formation of the Altun fault began in the middle or upper Carboniferous. It was characteristic of the sinistral strike\|slip\|thrust before Eocene, of the thrust\|sinistral strike\|slip during Oligocene—Miocene, and of the normal slip, and thrust\|sinistral strike\|slip simultaneously since Miocene.
基金Project supported by the National Natural Science Foundation of China (No. 10272037).
文摘This paper presents an extension of a displacement discontinuity method with cracktip elements （a boundary element method） proposed by the author for fatigue crack growth analysis in plane elastic media under mixed-mode conditions. The boundary element method consists of the non-singular displacement discontinuity elements presented by Crouch and Starfield and the crack-tip displacement discontinuity elements due to the author. In the boundary element implementation the left or right crack-tip element is placed locally at the corresponding left or right crack tip on top of the non-singular displacement discontinuity elements that cover the entire crack surface and the other boundaries. Crack growth is simulated with an incremental crack extension analysis based on the maximum circumferential stress criterion. In the numerical simulation, for each increment of crack extension, remeshing of existing boundaries is not required because of an intrinsic feature of the numerical approach. Crack growth is modeled by adding new boundary elements on the incremental crack extension to the previous crack boundaries. At the same time, the element characteristics of some related elements are adjusted according to the manner in which the boundary element method is implemented. As an example, the fatigue growth process of cracks emanating from a circular hole in a plane elastic plate is simulated using the numerical simulation approach.
基金Supported by the Natural Science Foundation of Nanjing Joint Center of Atmospheric Research(NJCAR2016MS02)National Natural Science Foundation of China(41205073,41275012,and 41275099)
文摘A convection-allowing ensemble forecast experiment on a squall line was conducted based on the breeding growth mode （BGM）. Meanwhile, the probability matched mean （PMM） and neighborhood ensemble probability （NEP） methods were used to optimize the associated precipitation forecast. The ensemble forecast predicted the precipita- tion tendency accurately, which was closer to the observation than in the control forecast. For heavy rainfall, the pre- cipitation center produced by the ensemble forecast was also better. The Fractions Skill Score （FSS） results indicated that the ensemble mean was skillful in light rainfall, while the PMM produced better probability distribution of pre- cipitation for heavy rainfall. Preliminary results demonstrated that convection-allowing ensemble forecast could im- prove precipitation forecast skill through providing valuable probability forecasts. It is necessary to employ new methods, such as the PMM and NEP, to generate precipitation probability forecasts. Nonetheless, the lack of spread and the overprediction of precipitation by the ensemble members are still problems that need to be solved.
文摘The Altun (or Altyn Tagh) fault displays a geometry of overlapping of linear and arcuate segments and shows strong inhomogeneity in time and space. It is a gigantic fault system with complex mechanical behaviours including thrusting, sinistral strike slip and normal slip. The strike slip and normal slip mainly occurred in the Cretaceous—Cenozoic and Plio-Quaternary respectively, whereas the thrusting was a deformation event that has played a dominant role since the late Palaeozoic (for a duration of about 305 Ma). The formation of the Altun fault was related to strong inhomogeneous deformation of the massifs on its two sides (in the hinterland of the Altun Mountains contractional deformation predominated and in the Qilian massif thrust propagation was dominant). The fault experienced a dynamic process of successive break-up and connection of its segments and gradual propagation, which was synchronous with the development of an overstep thrust sequence in the Qilian massif and the uplift of the Qinghai-Tibet plateau. With southward propagation of the thrust sequence and continued uplift of the plateau, the NE tip of the Altun fault moved in a NE direction, while the SW tip grew in a SW direction.
基金Project supported by the National Magnetic Confinement Fusion Science Program of China （Grant No. 2009GB 101002）.
文摘An analytical expression of the peeling mode in the near separatrix region of diverted tokamak plasma is derived. It is shown that in diverted plasmas both with single and double X points, though the perturbed potential energy of the unstable peeling mode tends to be large, its growth rate becomes very small due to the even larger kinetic energy. Compared to some recent studies that give qualitatively correct results about this growth rate, our result is directly related with the diverted equilibrium quantities suitable for application to realistic experiments.
文摘In this paper, the economic growth factors are classified into two types and three kinds by the growth rate function of Solow. Based on their contribution, the economic growth mode is classified into three types and eight kinds. The case analysis of the classfication of economic growth mode is given. Finally, the paper gives the economic growth function which describes the principle of interaction among economic growth factors.
基金Philosophical and Social Science Research Project in Colleges and Universities of Jiangsu Province in 2010 (2010SJD790005)
文摘The development mode of mid-small cities in northern Jiangsu is analyzed on the Growth Pole theory.Depending on scales,endowment of resources,geographical positions,and industrial advantages of mil-small cities,we can divide the development mode of those mid-small cities within this context into five types:development through integration into big cities;independent development;resource-dependent development;single industry development;and mixed industry development.
