Particle image velocimetry and numerical simulation results of juncture flows were analyzed to parametrically investigate topology transition. The vortex system evolutions from non-vortex to multi-vortex with variatio...Particle image velocimetry and numerical simulation results of juncture flows were analyzed to parametrically investigate topology transition. The vortex system evolutions from non-vortex to multi-vortex with variations in obstacle bluntness, obstacle width, flow velocity, and boundary layer thickness are discussed from the perspective of velocity characteristic lines. The velocity characteristic lines of u = 0, υ = 0, and ∇^(2) υ = 0 are adopted to describe the vortex system evolution. The motions of the characteristic lines with juncture flow parameters are described in detail, and the corresponding reflections of the vortex system patterns are illustrated. A panoramic picture of the development of velocity characteristic lines corresponding to the HSV topology transition from a non-vortex to a multi-vortex system with variations in the juncture flow parameter is established. Two methods for determining the attachment/separation pattern of the most upstream singularity are proposed. One method is based on the number of intersections of the u = 0 and υ = 0 velocity characteristic curve lines, and the other is based on the relative positions of the most upstream feet of the u = 0 and υ = 0 loop curves with both feet attached to the wall.展开更多
The leaf photosynthesis and nitrogen（N） translocation in three large-spike lines and control cultivar（Xi＇nong 979） of winter wheat（Triticum aestivum L.） were studied in 2010–2011 and 2011–2012. The objectives...The leaf photosynthesis and nitrogen（N） translocation in three large-spike lines and control cultivar（Xi＇nong 979） of winter wheat（Triticum aestivum L.） were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates（Pn） were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency（Fv/Fm）, PSII actual quantum efficiency（Ф（PSII））, photochemical quenching coefficient（qP）, PSII reaction center activity（Fv′/Fm′） and water-use efficiency（WUE） of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms＋sheathes〉rachis＋glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.展开更多
A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of ...A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.展开更多
A cell line designated as Ca 761-86 has been established from the solid mouse mammary cancer (Ca 761) by suspension culture. It has been passaged for more than 212 generations. Moderate round cells were predominant an...A cell line designated as Ca 761-86 has been established from the solid mouse mammary cancer (Ca 761) by suspension culture. It has been passaged for more than 212 generations. Moderate round cells were predominant and most of them were mononuclear. Some characteristics of malignant cells and A-type viral-like particles were observed by electron microscopy. The results of cytochemical studies (DNA, RNA, SDH, 5' AMPase, ACP etc.) were comparable to the ultramicroscopic results. It multiplied approximately 27.4 fold on day 5 with mitotic index reaching 1.8% on day 3. This cell line was a hyperdiploid with karyotype of 45 or 45, -2X, tril2, tri17, +M1-5. Cell agglutination was observed when treated with ConA (≥7 fig, ml). Spontaneous agglutination might also take place without adding any ConA. After 5×106 cells of Ca 761-86 suspension were transplanted into the normal inbred 615 mice by different ways (subcutan eous, intrafoot-pad or intraperitoneal), the transplan lability rate reached 100%. Spontaneous remission was never observed and its metastatic ability reserved. PPLO were not detected. Ca 761-86 may be of value for practical purposes.展开更多
The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the an...The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.展开更多
In this work,we study wave state transitions of the(2+1)-dimensional Kortewegde Vries-Sawada-Kotera-Ramani(2KdVSKR)equation by analyzing the characteristic line and phase shift.By converting the wave parameters of the...In this work,we study wave state transitions of the(2+1)-dimensional Kortewegde Vries-Sawada-Kotera-Ramani(2KdVSKR)equation by analyzing the characteristic line and phase shift.By converting the wave parameters of the N-soliton solution into complex numbers,the breath wave solution is constructed.The lump wave solution is derived through the long wave limit method.Then,by choosing appropriate parameter values,we acquire a number of transformed nonlinear waves whose gradient relation is discussed according to the ratio of the wave parameters.Furthermore,we reveal transition mechanisms of the waves by exploring the nonlinear superposition of the solitary and periodic wave components.Subsequently,locality,oscillation properties and evolutionary phenomenon of the transformed waves are presented.And we also prove the change in the geometrical properties of the characteristic lines leads to the phenomena of wave evolution.Finally,for higher-order waves,a range of interaction models are depicted along with their evolutionary phenomena.And we demonstrate that their diversity is due to the fact that the solitary and periodic wave components produce different phase shifts caused by time evolution and collisions.展开更多
A simple wave is defined as a flow in a region whose image is a curve in the phase space. It is well known that ＂the theory of simple waves is fundamental in building up the solutions of flow problems out of elementa...A simple wave is defined as a flow in a region whose image is a curve in the phase space. It is well known that ＂the theory of simple waves is fundamental in building up the solutions of flow problems out of elementary flow patterns＂ see Courant and Friedrichs＇s chassical book ＂Supersonic Flow and Shock Waves＂. This paper mainly concerned with the geometric construction of simple waves for the 2D pseudo-steady compressible Euler system. Based on the geometric interpretation, the expansion or compression simple wave flow construction around a pseudo-stream line with a bend part are constructed. It is a building block that appears in the global solution to four contact discontinuities Riemann problems.展开更多
The curved surface （CS） effect on nanosilicon plays a main role in the activation for emission and photonic manipulation. The CS effect breaks the symmetrical shape of nanosilicon on which some bonds can produce loc...The curved surface （CS） effect on nanosilicon plays a main role in the activation for emission and photonic manipulation. The CS effect breaks the symmetrical shape of nanosilicon on which some bonds can produce localized electron states in the band gap. The investigation in calculation and experiment demonstrates that the different curvatures can form the characteristic electron states for some special bonding on the nanosilicon surface, which are related to a series of peaks in photoluminecience （PL）, such as LN, LNO, Lo1, and Lo2 lines in PL spectra due to Si-N, Si-NO, Si=O, and Si-O-Si bonds on curved surface, respectively. Si-Yb bond on curved surface of Si nanostructures can provide the localized states in the band gap deeply and manipulate the emission wavelength into the window of optical communication by the CS effect, which is marked as the Lyb line of electroluminescence （EL） emission.展开更多
It is necessary to understand the features of air pressure in a drainage stack of a high-rise building for properly designing and operating a drainage system. This paper presents a mathematical model for predicting th...It is necessary to understand the features of air pressure in a drainage stack of a high-rise building for properly designing and operating a drainage system. This paper presents a mathematical model for predicting the stack performance. A step function is used to describe the effect of the air entrainment caused by the water discharged from branch pipes. An additional source term is introduced to reflect the gas-liquid interphase interaction （GLII） and stack base effect. The drainage stack is divided into upper and base parts. The air pressure in the upper part is predicted by a total variation diminishing （TVD） scheme, while in the base part, it is predicted by a characteristic line method （CLM）. The predicted results are compared with the data measured in a real-scale high- rise test building. It is found that the additional source term in the present model is effective. It intensively influences the air pressure distribution in the stack. The air pressure is also sensitive to the velocity-adjusting parameter （VAP）, the branch pipe air entrainment, and the conditions on the stack bottom.展开更多
The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-...The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-dwarfing genes had significantlypositive effects on kernel number and grain weight per spike, and had significantlynegative effects on 1000-grain weight comparing to the tall line(rht) and the Rht3 line.The Rht3 dwarfing gene had a significantly negative effect on kernel number per spike,and had positive effect on 1000-grain weight. The combination of the Rht2 and Rht3 geneshowed significantly negative effect on yield components. All of these 5 dwarfing orsemidwarfing genotypes mentioned above had a significantly negative effect on plantheight and no significant effect on the area of flag leaf, spikelets per spike and spikelength.展开更多
The adiabatic shear instability of ductile materials has attracted more and more attentions of researchers and groups,who have been sparing no effort in further understanding of the underlying mechanism since the firs...The adiabatic shear instability of ductile materials has attracted more and more attentions of researchers and groups,who have been sparing no effort in further understanding of the underlying mechanism since the first experimental depiction of adiabatic shear instability by Zener and Hollomon.As for the adiabatic shear instability,many factors account for its occurrence,including heat conduction,inertia effect,microstructure effect and so on.However,lots of experimental evidence has shown that metal materials display a strong size effect when the characteristic length scale is in the order of microns.The size effect has also been observed in the analysis of shear band in the ductile materials because the order of the bandwidth stays within the microscale range.However,a comprehensive understanding of the whole process of adiabatic shear banding(ASB),including the early onset and the subsequent evolution,is still lacking.In this work,a gradient plasticity model based on the Taylor-based nonlocal theory feasible for the linear perturbation analysis and convenient for numerical calculation is proposed to investigate the strain gradient on the onset of ASB and the coupling effect of heat conduction,inertia effect and strain gradient at the early stage,as well as on the subsequent evolution process at later stages.As for the onset of ASB,the linear perturbation method is used to consider the effect on the initial formation of ASB.After the investigation of the onset of ASB.the characteristic line method is applied to describe the subsequent nonlinear evolution process of ASB.Three stages of ASB evolution are clearly depicted during the evolution process,and the significance of size effect on the ASB nonlinear evolution process of ASB at different stages is analyzed.With the help of linear perturbation analysis and characteristic line method,a comprehensive description of the role of strain gradient in the ASB from the early onset to the end of the evolution is provided.展开更多
By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratificati...By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratification is obtained. The solution shows that not only the variation of amplitude of the gravity wave but also the variation of wavelength and the width of the envelope are affected by the horizontal heterogeneity. As the wave envelope moves from a region, of strong stratification to a weak one, the horizontal wavelength will become shorter, the width of the envelope will narrow and its amplitude will increase. The variation of stratification with time cannot lead to the variation of wavelength and envelope width, but the amplitude of the wave envelope will increase while the amplitude of the wave decreases in time.展开更多
It is impossible,mathematically, to use a time series which is regarded as a set of observational facts of a dynamicsystem to reconstruct the particular system.Physically, however, with a few assumptions put, a dynami...It is impossible,mathematically, to use a time series which is regarded as a set of observational facts of a dynamicsystem to reconstruct the particular system.Physically, however, with a few assumptions put, a dynamic system canbe rebuilt approximately by means of observational facts.This is the goal of the so called invariant quantity method(IQM),whose research and experiment are of potential significance to atmospheric sciences.展开更多
The magnesium has some excellent properties such as ligh quality, high specific strength and stiffness, high damp and reeoverd easily compared with steel, aluminium, engineering plastic. So the application and exploit...The magnesium has some excellent properties such as ligh quality, high specific strength and stiffness, high damp and reeoverd easily compared with steel, aluminium, engineering plastic. So the application and exploitation of magnesium arose extensive attention of the public.展开更多
The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory...The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory takes account of different effects of intermediate principal stress on yielding or failure and the SD effect (tensile-compression strength difference) of materials. Various conventional axisymmetric characteristics line theories, which are based on the Haar-von Karman plastic condition, Szczepinski hypothesis, Tresca criterion, von Mises criterion and Mohr-Coulomb theory, are special cases of the new theory. Besides, a series of new spacial axisymmetric characteristics fields for different materials can be introduced. It forms a unified spacial axisymmetric characteristics theory. Two examples are calculated with the new theory, the results are compared with those obtained by the finite element program UEPP and those based on the Mohr-Coulomb strength theory. It is shown that the new theory is reliable and feasible. The economic benefit can be obtained from the engineering application of the new theory.展开更多
Background There were only 3 multiple myeloma (MM) cell lines established in China. In this study,we succeeded in establishing a novel MM cell line and analyzed its biological characteristics. Methods Mononuclear...Background There were only 3 multiple myeloma (MM) cell lines established in China. In this study,we succeeded in establishing a novel MM cell line and analyzed its biological characteristics. Methods Mononuclear cells isolated from the peripheral blood (PB) and bone marrow (BM) of a patient with advanced MM (λ light chain type) were cultured in medium. Cell morphology was analyzed by Wright-Giemsa-staining and cytochemical staining,immunophenotyping by flow cytometry and cytogenetic analysis by chromosome RHG-banding technique. Quantitative fluorescent polymerase chain reaction (PCR) was used to detect Epstein - Barr virus (EBV) DNA. Results The established cell line could survive and proliferate in the presence of feeder cells or conditioned medium. The cells secreted λ light chain and were negative for EBV. The Wright-Giemsa-staining showed typical plasmablast or plasma cell morphology. The cytochemical staining of the cells showed the following reactivity patterns: positive for acid phosphatase,negative for myeloperoxidase. The immunoprofile of the cells was concordant with that of MM cells: positive for CD_ 10 ,CD_ 28 ,CD_ 38 ,CD_ 138 ,CD_ 56 ,CD_ 49d ,CD_ 44 ,CD_ 54 and CD_ 58 ,negative for CD_ 19 , CD_ 40 ,CD_ 95 ,CD_ 95L ,CD_ 34 ,CD_2 and CD_5. The cytogenetic analysis showed complex chromosome abnormality of i (1q+),8q+,13q+,i (17q),i (18q) and +M. There was no difference in morphology,immunophenotype and cytogenetics between cells from PB and BM. Conclusions An MM cell line secreting λ light chain named CZ-1 was established. The cells from both PB and BM have the same biological characteristics.展开更多
In this paper,we investigate the transformation phenomenon of the first-order breather and the second-order breather.First,we obtain the 2-solitary wave and 4-solitary wave solutions of the(2+1)-dimensional Boiti-Leon...In this paper,we investigate the transformation phenomenon of the first-order breather and the second-order breather.First,we obtain the 2-solitary wave and 4-solitary wave solutions of the(2+1)-dimensional Boiti-Leon-Manna-Pempinelli(BLMP)equation by using the Hirota bilinear method.Then by analyzing and controlling characteristic lines,we derive several types of nonlinear transformantion waves and give the corresponding figures.展开更多
To investigate the dynamic characteristics of the thermal conditions of hot-water district-heating networks, a dynamic modeling method is proposed with consideration of the heat dissipations in pipes and the character...To investigate the dynamic characteristics of the thermal conditions of hot-water district-heating networks, a dynamic modeling method is proposed with consideration of the heat dissipations in pipes and the characteristic line method is adopted to solve it. Besides, the influences of different errors, space steps and initial values on the convergence of the dynamic model results are analyzed for a model network. Finally, a part of a certain city district-heating system is simulated and the results are compared with the actual operation data in half an hour from 6 secondary heat stations. The results indicate that the relative errors for the supply pressure and temperature in 5 stations are all within 2%, except in one station, where the relative error approaches 4%. So the proposed model and algorithm are validated.展开更多
基金supported by the State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures(Grant No.ZZ2021-04)the Science and Technology Project of the Hebei Education Department(Grant No.QN2021230)the Natural Science Foundation of Hebei Province(Grant No.E2019210026).
文摘Particle image velocimetry and numerical simulation results of juncture flows were analyzed to parametrically investigate topology transition. The vortex system evolutions from non-vortex to multi-vortex with variations in obstacle bluntness, obstacle width, flow velocity, and boundary layer thickness are discussed from the perspective of velocity characteristic lines. The velocity characteristic lines of u = 0, υ = 0, and ∇^(2) υ = 0 are adopted to describe the vortex system evolution. The motions of the characteristic lines with juncture flow parameters are described in detail, and the corresponding reflections of the vortex system patterns are illustrated. A panoramic picture of the development of velocity characteristic lines corresponding to the HSV topology transition from a non-vortex to a multi-vortex system with variations in the juncture flow parameter is established. Two methods for determining the attachment/separation pattern of the most upstream singularity are proposed. One method is based on the number of intersections of the u = 0 and υ = 0 velocity characteristic curve lines, and the other is based on the relative positions of the most upstream feet of the u = 0 and υ = 0 loop curves with both feet attached to the wall.
基金financially supported by the National Natural Science Foundation of China (31370425, 31501276)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2015BAD22B01)
文摘The leaf photosynthesis and nitrogen（N） translocation in three large-spike lines and control cultivar（Xi＇nong 979） of winter wheat（Triticum aestivum L.） were studied in 2010–2011 and 2011–2012. The objectives of this study were to investigate the differences in the physiological characteristics of large-spike lines and control cultivar and identify the limiting factors that play a role in improving the yield of breeding materials. The average yield, grain number per spike, kernel weight per spike, and 1 000-kernel weight of the large-spike lines were 16.0, 26.8, 42.6, and 15.4%, respectively, significantly higher than those of control. The average photosynthetic rates（Pn） were not significant between the large-spike lines and control cultivar during the active growth period. The average PSII maximum energy conversion efficiency（Fv/Fm）, PSII actual quantum efficiency（Ф（PSII））, photochemical quenching coefficient（qP）, PSII reaction center activity（Fv′/Fm′） and water-use efficiency（WUE） of the large-spike lines were 1.0, 5.1, 3.6, 0.8, and 43.4%, respectively, higher than those of the control during the active growth stages. The N distribution proportions in different tissues were ranked in the order of grains〉culms＋sheathes〉rachis＋glumes〉flag leaves〉penultimate leaves〉remain leaves. This study suggested that utilization of the large-spike wheat might be a promising approach to obtain higher grain yield in Northwest China.
基金National Natural Science Foundation of China(Grant No.11872120).
文摘A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.
文摘A cell line designated as Ca 761-86 has been established from the solid mouse mammary cancer (Ca 761) by suspension culture. It has been passaged for more than 212 generations. Moderate round cells were predominant and most of them were mononuclear. Some characteristics of malignant cells and A-type viral-like particles were observed by electron microscopy. The results of cytochemical studies (DNA, RNA, SDH, 5' AMPase, ACP etc.) were comparable to the ultramicroscopic results. It multiplied approximately 27.4 fold on day 5 with mitotic index reaching 1.8% on day 3. This cell line was a hyperdiploid with karyotype of 45 or 45, -2X, tril2, tri17, +M1-5. Cell agglutination was observed when treated with ConA (≥7 fig, ml). Spontaneous agglutination might also take place without adding any ConA. After 5×106 cells of Ca 761-86 suspension were transplanted into the normal inbred 615 mice by different ways (subcutan eous, intrafoot-pad or intraperitoneal), the transplan lability rate reached 100%. Spontaneous remission was never observed and its metastatic ability reserved. PPLO were not detected. Ca 761-86 may be of value for practical purposes.
基金supported by the National Natural Science Foundation of China(Grant Nos.12473001,11975072,11875102,11835009,and 11965013)the National SKA Program of China(Grant Nos.2022SKA0110200 and 2022SKA0110203)+1 种基金the National 111 Project(Grant No.B16009)supported by Yunnan High-level Talent Training Support Plan Young&Elite Talents Project(Grant No.YNWR-QNBJ-2018-181).
文摘The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.
基金supported by the National Natural Science Foundation of China(12371255,11975306)the Xuzhou Basic Research Program Project(KC23048)+1 种基金the Six Talent Peaks Project in Jiangsu Province(JY-059)the 333 Project in Jiangsu Province and the Fundamental Research Funds for the Central Universities of CUMT(2024ZDPYJQ1003).
文摘In this work,we study wave state transitions of the(2+1)-dimensional Kortewegde Vries-Sawada-Kotera-Ramani(2KdVSKR)equation by analyzing the characteristic line and phase shift.By converting the wave parameters of the N-soliton solution into complex numbers,the breath wave solution is constructed.The lump wave solution is derived through the long wave limit method.Then,by choosing appropriate parameter values,we acquire a number of transformed nonlinear waves whose gradient relation is discussed according to the ratio of the wave parameters.Furthermore,we reveal transition mechanisms of the waves by exploring the nonlinear superposition of the solitary and periodic wave components.Subsequently,locality,oscillation properties and evolutionary phenomenon of the transformed waves are presented.And we also prove the change in the geometrical properties of the characteristic lines leads to the phenomena of wave evolution.Finally,for higher-order waves,a range of interaction models are depicted along with their evolutionary phenomena.And we demonstrate that their diversity is due to the fact that the solitary and periodic wave components produce different phase shifts caused by time evolution and collisions.
基金supported by the National Natural Science Foundation of China (No.0971130)the Shanghai Leading Academic Discipline Project (No.J50101)
文摘A simple wave is defined as a flow in a region whose image is a curve in the phase space. It is well known that ＂the theory of simple waves is fundamental in building up the solutions of flow problems out of elementary flow patterns＂ see Courant and Friedrichs＇s chassical book ＂Supersonic Flow and Shock Waves＂. This paper mainly concerned with the geometric construction of simple waves for the 2D pseudo-steady compressible Euler system. Based on the geometric interpretation, the expansion or compression simple wave flow construction around a pseudo-stream line with a bend part are constructed. It is a building block that appears in the global solution to four contact discontinuities Riemann problems.
基金Project supported by the National Natural Science Foundation of China(Grant No.11264007)
文摘The curved surface （CS） effect on nanosilicon plays a main role in the activation for emission and photonic manipulation. The CS effect breaks the symmetrical shape of nanosilicon on which some bonds can produce localized electron states in the band gap. The investigation in calculation and experiment demonstrates that the different curvatures can form the characteristic electron states for some special bonding on the nanosilicon surface, which are related to a series of peaks in photoluminecience （PL）, such as LN, LNO, Lo1, and Lo2 lines in PL spectra due to Si-N, Si-NO, Si=O, and Si-O-Si bonds on curved surface, respectively. Si-Yb bond on curved surface of Si nanostructures can provide the localized states in the band gap deeply and manipulate the emission wavelength into the window of optical communication by the CS effect, which is marked as the Lyb line of electroluminescence （EL） emission.
基金Project supported by the National Natural Science Foundation of China (No. 10972212)
文摘It is necessary to understand the features of air pressure in a drainage stack of a high-rise building for properly designing and operating a drainage system. This paper presents a mathematical model for predicting the stack performance. A step function is used to describe the effect of the air entrainment caused by the water discharged from branch pipes. An additional source term is introduced to reflect the gas-liquid interphase interaction （GLII） and stack base effect. The drainage stack is divided into upper and base parts. The air pressure in the upper part is predicted by a total variation diminishing （TVD） scheme, while in the base part, it is predicted by a characteristic line method （CLM）. The predicted results are compared with the data measured in a real-scale high- rise test building. It is found that the additional source term in the present model is effective. It intensively influences the air pressure distribution in the stack. The air pressure is also sensitive to the velocity-adjusting parameter （VAP）, the branch pipe air entrainment, and the conditions on the stack bottom.
基金supported by the Provincial Natural Science Foundation of Hebei,China(396313).
文摘The value of different dwarfing genes in winter wheat breeding was studied using 6 near-isogenic lines carrying different Rht dwarfing genes over three years experiment.Results showed that both the Rht1 and Rht2 semi-dwarfing genes had significantlypositive effects on kernel number and grain weight per spike, and had significantlynegative effects on 1000-grain weight comparing to the tall line(rht) and the Rht3 line.The Rht3 dwarfing gene had a significantly negative effect on kernel number per spike,and had positive effect on 1000-grain weight. The combination of the Rht2 and Rht3 geneshowed significantly negative effect on yield components. All of these 5 dwarfing orsemidwarfing genotypes mentioned above had a significantly negative effect on plantheight and no significant effect on the area of flag leaf, spikelets per spike and spikelength.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.11522220,11772268,11527803,11390361).
文摘The adiabatic shear instability of ductile materials has attracted more and more attentions of researchers and groups,who have been sparing no effort in further understanding of the underlying mechanism since the first experimental depiction of adiabatic shear instability by Zener and Hollomon.As for the adiabatic shear instability,many factors account for its occurrence,including heat conduction,inertia effect,microstructure effect and so on.However,lots of experimental evidence has shown that metal materials display a strong size effect when the characteristic length scale is in the order of microns.The size effect has also been observed in the analysis of shear band in the ductile materials because the order of the bandwidth stays within the microscale range.However,a comprehensive understanding of the whole process of adiabatic shear banding(ASB),including the early onset and the subsequent evolution,is still lacking.In this work,a gradient plasticity model based on the Taylor-based nonlocal theory feasible for the linear perturbation analysis and convenient for numerical calculation is proposed to investigate the strain gradient on the onset of ASB and the coupling effect of heat conduction,inertia effect and strain gradient at the early stage,as well as on the subsequent evolution process at later stages.As for the onset of ASB,the linear perturbation method is used to consider the effect on the initial formation of ASB.After the investigation of the onset of ASB.the characteristic line method is applied to describe the subsequent nonlinear evolution process of ASB.Three stages of ASB evolution are clearly depicted during the evolution process,and the significance of size effect on the ASB nonlinear evolution process of ASB at different stages is analyzed.With the help of linear perturbation analysis and characteristic line method,a comprehensive description of the role of strain gradient in the ASB from the early onset to the end of the evolution is provided.
基金This study was Supported by the National Special Key Project Fund(No.G1998040907).
文摘By the use of the WKBJ method combined with the characteristic line method, the asymptotic solution of a gravity wave envelope in the atmosphere of horizontal heterogeneous stratification and time-varying stratification is obtained. The solution shows that not only the variation of amplitude of the gravity wave but also the variation of wavelength and the width of the envelope are affected by the horizontal heterogeneity. As the wave envelope moves from a region, of strong stratification to a weak one, the horizontal wavelength will become shorter, the width of the envelope will narrow and its amplitude will increase. The variation of stratification with time cannot lead to the variation of wavelength and envelope width, but the amplitude of the wave envelope will increase while the amplitude of the wave decreases in time.
文摘It is impossible,mathematically, to use a time series which is regarded as a set of observational facts of a dynamicsystem to reconstruct the particular system.Physically, however, with a few assumptions put, a dynamic system canbe rebuilt approximately by means of observational facts.This is the goal of the so called invariant quantity method(IQM),whose research and experiment are of potential significance to atmospheric sciences.
文摘The magnesium has some excellent properties such as ligh quality, high specific strength and stiffness, high damp and reeoverd easily compared with steel, aluminium, engineering plastic. So the application and exploitation of magnesium arose extensive attention of the public.
基金the National Natural Science Foundation of China (Grant No. 59779028).
文摘The unified strength theory proposed by Yu in 1991 is extended to spacial axisymmetric problem. A unified spacial axismymmetric characteristics line theory based on the unified strength theory is proposed. This theory takes account of different effects of intermediate principal stress on yielding or failure and the SD effect (tensile-compression strength difference) of materials. Various conventional axisymmetric characteristics line theories, which are based on the Haar-von Karman plastic condition, Szczepinski hypothesis, Tresca criterion, von Mises criterion and Mohr-Coulomb theory, are special cases of the new theory. Besides, a series of new spacial axisymmetric characteristics fields for different materials can be introduced. It forms a unified spacial axisymmetric characteristics theory. Two examples are calculated with the new theory, the results are compared with those obtained by the finite element program UEPP and those based on the Mohr-Coulomb strength theory. It is shown that the new theory is reliable and feasible. The economic benefit can be obtained from the engineering application of the new theory.
文摘Background There were only 3 multiple myeloma (MM) cell lines established in China. In this study,we succeeded in establishing a novel MM cell line and analyzed its biological characteristics. Methods Mononuclear cells isolated from the peripheral blood (PB) and bone marrow (BM) of a patient with advanced MM (λ light chain type) were cultured in medium. Cell morphology was analyzed by Wright-Giemsa-staining and cytochemical staining,immunophenotyping by flow cytometry and cytogenetic analysis by chromosome RHG-banding technique. Quantitative fluorescent polymerase chain reaction (PCR) was used to detect Epstein - Barr virus (EBV) DNA. Results The established cell line could survive and proliferate in the presence of feeder cells or conditioned medium. The cells secreted λ light chain and were negative for EBV. The Wright-Giemsa-staining showed typical plasmablast or plasma cell morphology. The cytochemical staining of the cells showed the following reactivity patterns: positive for acid phosphatase,negative for myeloperoxidase. The immunoprofile of the cells was concordant with that of MM cells: positive for CD_ 10 ,CD_ 28 ,CD_ 38 ,CD_ 138 ,CD_ 56 ,CD_ 49d ,CD_ 44 ,CD_ 54 and CD_ 58 ,negative for CD_ 19 , CD_ 40 ,CD_ 95 ,CD_ 95L ,CD_ 34 ,CD_2 and CD_5. The cytogenetic analysis showed complex chromosome abnormality of i (1q+),8q+,13q+,i (17q),i (18q) and +M. There was no difference in morphology,immunophenotype and cytogenetics between cells from PB and BM. Conclusions An MM cell line secreting λ light chain named CZ-1 was established. The cells from both PB and BM have the same biological characteristics.
文摘In this paper,we investigate the transformation phenomenon of the first-order breather and the second-order breather.First,we obtain the 2-solitary wave and 4-solitary wave solutions of the(2+1)-dimensional Boiti-Leon-Manna-Pempinelli(BLMP)equation by using the Hirota bilinear method.Then by analyzing and controlling characteristic lines,we derive several types of nonlinear transformantion waves and give the corresponding figures.
基金supported by the Scientific Development Pro-gram of Shandong Province(Grant No.2012GGB01071)the Doctoral Scientific Research Fund Program of Shandong Jianzhu University (Grant No. XNBS1225)the School Scientific Research Fund Program of Shandong Jianzhu University (Grant No. XN110108)
文摘To investigate the dynamic characteristics of the thermal conditions of hot-water district-heating networks, a dynamic modeling method is proposed with consideration of the heat dissipations in pipes and the characteristic line method is adopted to solve it. Besides, the influences of different errors, space steps and initial values on the convergence of the dynamic model results are analyzed for a model network. Finally, a part of a certain city district-heating system is simulated and the results are compared with the actual operation data in half an hour from 6 secondary heat stations. The results indicate that the relative errors for the supply pressure and temperature in 5 stations are all within 2%, except in one station, where the relative error approaches 4%. So the proposed model and algorithm are validated.
