Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote ...Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.展开更多
Novel headstand pyrocarbon cones （HPCs） with hollow structure were developed on the surfaces of pyrocarbon layers of the carbon/carbon （C/C） composites at 650-750 °C by the electromagnetic-field-assisted chem...Novel headstand pyrocarbon cones （HPCs） with hollow structure were developed on the surfaces of pyrocarbon layers of the carbon/carbon （C/C） composites at 650-750 °C by the electromagnetic-field-assisted chemical vapor deposition in the absence of catalysts. The fine microstructures of the HPCs were characterized by high-resolution transmission electron microscopy. The results show that the textural features of the HPCs directly transfer from turbostratic structure in roots to a well-ordered high texture in stems. And the degree of high texture ordering decreases gradually from the stem to the tail of the HPCs. The formation mechanism of the HPCs was inferred as the comprehensive effect of polarization induction on electromagnetic fields and particle-filler property under disruptive discharge.展开更多
The present paper deals with two new ethmid moths from China: Ethmia damaoshanae sp.nov. and Ethmia jingdongensis sp.nov. Another two species Ethmia dodecea (Haworth) and Ethmia ultima Sattler are reported for the f...The present paper deals with two new ethmid moths from China: Ethmia damaoshanae sp.nov. and Ethmia jingdongensis sp.nov. Another two species Ethmia dodecea (Haworth) and Ethmia ultima Sattler are reported for the first time from the country. The genitalia of the new species are figured.展开更多
Some properties for convex cones are discussed, which are used to obtain an equivalent condition and another important property for nearly cone-subconvexlike set-valued functions. Under the nearly cone-subconvexlikene...Some properties for convex cones are discussed, which are used to obtain an equivalent condition and another important property for nearly cone-subconvexlike set-valued functions. Under the nearly cone-subconvexlikeness, some characterizations of the super efficiency are given in terms of scalarization and Lagrangian multipliers. Related results are generalized.展开更多
Some properties of convex cones are obtained and are used to derive several equivalent conditions as well as another important property for nearly cone-subconvexlike set-valued functions. Under the assumption of nearl...Some properties of convex cones are obtained and are used to derive several equivalent conditions as well as another important property for nearly cone-subconvexlike set-valued functions. Under the assumption of nearly cone-subconvexlikeness,a Lagrangian multiplier theorem on Benson proper efficiency is presented. Related results are generalized.展开更多
Land subsidence is a severe hazard threatening Tanggu, a flat lowland area, and evidences of land subsidence can be seen throughout the city. A new reasonable GPS network was set up in this area from 2008 to 2010. The...Land subsidence is a severe hazard threatening Tanggu, a flat lowland area, and evidences of land subsidence can be seen throughout the city. A new reasonable GPS network was set up in this area from 2008 to 2010. The monitoring data show that land subsidence was serious and two main subsidence cones were obviously formed in the region. One emerged at Hujiayuan, with the maximum rate reaching 60 ram/a, and the influence region enlarged prominently from 2005 to 2010. The other one occurred at Kaifaqu, which became obvious only after 2005, and it showed a decreasing tendency with time. To analyze the causes of ground settlement, a correlation between groundwater withdrawal and land subsidence was firstly made. The results confirmed that over-exploitation of groundwater was the major cause for the severe settlement in Hujiayuan. Meanwhile, the subsidence of Kaifaqu was also related to groundwater withdrawal before 2005. However, the relationship became unconspicuous after 2005. To find the cause of this abnormity, a three-dimensional finite element numerical model, coupled with groundwater flow and subsidence, was built. The simulation results indicate that the subsidence induced by high-rise buildings is serious, but the affected range is limited and it also shows a decreasing trend with time, corresponding to the subsidence characteristics at Kaifaqu. Therefore, more attention should be paid to this hazard induced by engineering construction besides groundwater withdrawal, as more high-rise buildings are under construction in Tanggu.展开更多
In this paper,we study a Dirichlet-type boundary value problem(BVP) of nonlinear fractional differential equation with an order α∈(3,4],where the fractional derivative D~α_(o^+)is the standard Riemann-Liouville fra...In this paper,we study a Dirichlet-type boundary value problem(BVP) of nonlinear fractional differential equation with an order α∈(3,4],where the fractional derivative D~α_(o^+)is the standard Riemann-Liouville fractional derivative.By constructing the Green function and investigating its properties,we obtain some criteria for the existence of one positive solution and two positive solutions for the above BVP.The Krasnosel'skii fixedpoint theorem in cones is used here.We also give an example to illustrate the applicability of our results.展开更多
In this paper,the boundary value problems of p-Laplacian functional differential equation are studied.By using a fixed point theorem in cones,some criteria for the existence of positive solutions are given.
Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central n...Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.展开更多
In this paper, we study the existence of nontrivial radial convex solutions of a singular Dirichlet problem involving the mean curvature operator in Minkowski space. The proof is based on a well-known fixed point theo...In this paper, we study the existence of nontrivial radial convex solutions of a singular Dirichlet problem involving the mean curvature operator in Minkowski space. The proof is based on a well-known fixed point theorem in cones. We deal with more general nonlinear term than those in the literature.展开更多
In this paper we present some new existence results for singular boundary value problems by Arzela-Ascoli theorem. In particular our nonlinearity may be singular in its dependent variable.
A new algebraic transition model is proposed based on a Structural Ensemble Dynamics(SED)theory of wall turbulence,for accurately predicting the hypersonic flow heat transfer on cone.The model defines the eddy viscosi...A new algebraic transition model is proposed based on a Structural Ensemble Dynamics(SED)theory of wall turbulence,for accurately predicting the hypersonic flow heat transfer on cone.The model defines the eddy viscosity in terms of a two-dimensional multi-regime distribution of a Stress Length(SL)function,and hence is named as SED-SL.This paper presents clear evidence of precise predictions of transition onset location and peak heat flux of a wide range of hypersonic Transitional Boundary Layers(TrBL)around straight cone at zero incidence,to an unprecedented accuracy as validated by over 70 measurements for varying five crucial influential factors(Mach number,temperature ratio,cone half angle,nose Reynolds number and noise level).The results demonstrate the universality of the postulated multi-regime similarity structure,in characterizing not only the spatial non-uniform distribution of the eddy viscosity in hypersonic TrBL on cone,but also the dependence of the transition onset location on the five influential factors.The latter yields a novel correlation formula for transition center Reynolds number which takes similar functional form as the SL function within the symmetry approach.It is concluded that the SED-SL model simulates TrBL around cone with uniformly high accuracy,and then points out to an optimistic alternative way to construct hypersonic transition model.展开更多
In this paper, we consider the positive solutions of fractional three-point boundary value problem of the form Dο^α＋u（t）＋f（t,u（t）,u＇（t）,…,u^（n-3）（5）,u^（n-2）（t））=0,u^（i）（0）=0,0≤i≤n-2,u^（n-...In this paper, we consider the positive solutions of fractional three-point boundary value problem of the form Dο^α＋u（t）＋f（t,u（t）,u＇（t）,…,u^（n-3）（5）,u^（n-2）（t））=0,u^（i）（0）=0,0≤i≤n-2,u^（n-2）（1）-βu^（n-2）（ξ）=0,where 0〈t〈1,n-1〈α≤n,n≥2,ξ Е（0,1）,βξ^a-n〈1. We first transform it into another equivalent boundary value problem. Then, we derive the Green＇s function for the equivalent boundary value problem and show that it satisfies certain properties. At last, by using some fixed-point theorems, we obtain the existence of positive solution for this problem. Example is given to illustrate the effectiveness of our result.展开更多
The existence of positive solutions for second order m-point boundary value problemx″-q(t)f(x,x′)x′=0, x(0)= m i=2 b ix(ξ i),x′(1)=αx′(0)are investigated,where ξ i,b i and α are constants satisfying...The existence of positive solutions for second order m-point boundary value problemx″-q(t)f(x,x′)x′=0, x(0)= m i=2 b ix(ξ i),x′(1)=αx′(0)are investigated,where ξ i,b i and α are constants satisfying 0=ξ 1<ξ 2<...<ξ m-1 <ξ m=1,b i≥0 for i=2,...,m with β∶= m i=2 b i∈[0,1), and α>1. Our approach is based on the fixed point theorem in cones.展开更多
Fossil Taiwania was discovered from the Lower Cretaceous Yixian Formation of Lingyuan City, western Liaoning Province, Northeast China. It is identified as a new species, Taiwania lingyuanensis sp. nov.. The present s...Fossil Taiwania was discovered from the Lower Cretaceous Yixian Formation of Lingyuan City, western Liaoning Province, Northeast China. It is identified as a new species, Taiwania lingyuanensis sp. nov.. The present specimen is preserved as impressions with well defined leaf shoots system and reproductive structures. Leaves are dimorphic, spirally and imbricately arranged. They are scale-like on the main and cone-bearing branchlets, and subulate to falcate-subulate on the juvenile or sterile shoots. The seed cones are singly elliptic, ovate or elongate-ovate and terminally borne on ultimate shoots, bearing 22–24 scale-bracts complexes imbricately and helically arranged around the cone axis, the bracts are broadovate, rhomboidal or hexagonal with entire margins. Both the leafy shoots morphology and reproductive structures are similar to extant Taiwania. Furthermore, geological distribution and molecular biological evidences support that Taiwania is probably originated from the eastern Asia at least in the Early Cretaceous and widely distributed in the North Hemisphere thereafter.展开更多
In this paper, we introduce the concept of generalized g-quasi-contractions in the setting of cone b-metric spaces over Banach algebras. By omitting the assump- tion of normality we establish common fixed point theore...In this paper, we introduce the concept of generalized g-quasi-contractions in the setting of cone b-metric spaces over Banach algebras. By omitting the assump- tion of normality we establish common fixed point theorems for the generalized g- quasi-contractions with the spectral radius r（λ） of the g-quasi-contractive constant vector λ satisfying r（λ） ∈[0,1） in the setting of cone b-metric spaces over Banach al- gebras, where the coefficient s satisfies s ≥ 1. The main results generalize, extend and unify several well-known comparable results in the literature.展开更多
文摘Harrat Lunayyir,a volcanic field in western Saudi Arabia,exhibits diverse geomorphological and topographical features shaped by volcanic,tectonic,and climatic processes.This study integrates field observations,remote sensing,and GIS analysis to investigate the spatial distribution and relationships between volcanic landforms,lava flows,and topographical variation result obtained is a morphological classification of the cinder cones of Harrat Lunayyir,which can be sub-divided into four types:tephra rings,horseshoe-shaped volcanoes,multiple volcanoes and volcanoes without craters.All of these are monogenetic volcanoes,unlike central volcanoes(stratovolcanoes)which live for tens or hundreds of thousands of years and erupt numerous times.In Harrat Lunayyir,there is a clear dominance of arched horseshoe-shaped volcanoes(58)over ring-shaped cinder cones(10),A1_symmetric cones(circular,uniform cinder cones with a single crater)(32),A2_asymmetric cones(elongated,irregular cones and may feature one or more craters)(8),volcanoes without craters(55)and multiple volcanoes(20).The classification presented in this paper makes it possible to include all morphological types of volcanoes found in the region.This fact also renders the present classification a useful tool to apply in other,both insular and continental volcanic areas to eventually analyze and systematize the study of eruptive edifices with similar traits.Hence,this research will explore the standard physical volcanology literature so as to follow accepted definitions.
基金Project (2011CB605801) supported by the National Basic Research Program of ChinaProject (2011M500127) supported by the China Postdoctoral Science Foundation+1 种基金Projects (50802115, 51102089) supported by the National Natural Science Foundation of ChinaProject supported by the Postdoctoral Fund of the Central South University, China
文摘Novel headstand pyrocarbon cones （HPCs） with hollow structure were developed on the surfaces of pyrocarbon layers of the carbon/carbon （C/C） composites at 650-750 °C by the electromagnetic-field-assisted chemical vapor deposition in the absence of catalysts. The fine microstructures of the HPCs were characterized by high-resolution transmission electron microscopy. The results show that the textural features of the HPCs directly transfer from turbostratic structure in roots to a well-ordered high texture in stems. And the degree of high texture ordering decreases gradually from the stem to the tail of the HPCs. The formation mechanism of the HPCs was inferred as the comprehensive effect of polarization induction on electromagnetic fields and particle-filler property under disruptive discharge.
文摘The present paper deals with two new ethmid moths from China: Ethmia damaoshanae sp.nov. and Ethmia jingdongensis sp.nov. Another two species Ethmia dodecea (Haworth) and Ethmia ultima Sattler are reported for the first time from the country. The genitalia of the new species are figured.
文摘Some properties for convex cones are discussed, which are used to obtain an equivalent condition and another important property for nearly cone-subconvexlike set-valued functions. Under the nearly cone-subconvexlikeness, some characterizations of the super efficiency are given in terms of scalarization and Lagrangian multipliers. Related results are generalized.
文摘Some properties of convex cones are obtained and are used to derive several equivalent conditions as well as another important property for nearly cone-subconvexlike set-valued functions. Under the assumption of nearly cone-subconvexlikeness,a Lagrangian multiplier theorem on Benson proper efficiency is presented. Related results are generalized.
基金supported by the State Key Development Program for Basic Research of China(Grant No2010CB428803)the Knowledge Innovation Projects of the Chinese Academy of Science(Grant No KZCX2-YW-Q03-02)
文摘Land subsidence is a severe hazard threatening Tanggu, a flat lowland area, and evidences of land subsidence can be seen throughout the city. A new reasonable GPS network was set up in this area from 2008 to 2010. The monitoring data show that land subsidence was serious and two main subsidence cones were obviously formed in the region. One emerged at Hujiayuan, with the maximum rate reaching 60 ram/a, and the influence region enlarged prominently from 2005 to 2010. The other one occurred at Kaifaqu, which became obvious only after 2005, and it showed a decreasing tendency with time. To analyze the causes of ground settlement, a correlation between groundwater withdrawal and land subsidence was firstly made. The results confirmed that over-exploitation of groundwater was the major cause for the severe settlement in Hujiayuan. Meanwhile, the subsidence of Kaifaqu was also related to groundwater withdrawal before 2005. However, the relationship became unconspicuous after 2005. To find the cause of this abnormity, a three-dimensional finite element numerical model, coupled with groundwater flow and subsidence, was built. The simulation results indicate that the subsidence induced by high-rise buildings is serious, but the affected range is limited and it also shows a decreasing trend with time, corresponding to the subsidence characteristics at Kaifaqu. Therefore, more attention should be paid to this hazard induced by engineering construction besides groundwater withdrawal, as more high-rise buildings are under construction in Tanggu.
基金Supported by the Research Fund for the Doctoral Program of High Education of China(20094407110001)Supported by the NSF of Guangdong Province(10151063101000003)
文摘In this paper,we study a Dirichlet-type boundary value problem(BVP) of nonlinear fractional differential equation with an order α∈(3,4],where the fractional derivative D~α_(o^+)is the standard Riemann-Liouville fractional derivative.By constructing the Green function and investigating its properties,we obtain some criteria for the existence of one positive solution and two positive solutions for the above BVP.The Krasnosel'skii fixedpoint theorem in cones is used here.We also give an example to illustrate the applicability of our results.
文摘In this paper,the boundary value problems of p-Laplacian functional differential equation are studied.By using a fixed point theorem in cones,some criteria for the existence of positive solutions are given.
基金supported by the NIH(NS53470)the Kentucky Spinal Cord and Head Injury Research Trust(#10-11A)the Department of Defense,CDMRP(SC090248/W81XWH-10-1-0778)
文摘Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.
基金supported by the Key Program of Scientific Research Fund for Young Teachers of AUST(QN2018109)the National Natural Science Foundation of China(11801008)+1 种基金supported by the Fundamental Research Funds for the Central Universities(2017B715X14)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX17_0508)
文摘In this paper, we study the existence of nontrivial radial convex solutions of a singular Dirichlet problem involving the mean curvature operator in Minkowski space. The proof is based on a well-known fixed point theorem in cones. We deal with more general nonlinear term than those in the literature.
文摘In this paper we present some new existence results for singular boundary value problems by Arzela-Ascoli theorem. In particular our nonlinearity may be singular in its dependent variable.
基金supported by the National Numerical WindTunnel Project,China(No.NNW2019ZT1-A03)the National Natural Science Foundation of China(Nos.91952201,11372008 and 11452002).
文摘A new algebraic transition model is proposed based on a Structural Ensemble Dynamics(SED)theory of wall turbulence,for accurately predicting the hypersonic flow heat transfer on cone.The model defines the eddy viscosity in terms of a two-dimensional multi-regime distribution of a Stress Length(SL)function,and hence is named as SED-SL.This paper presents clear evidence of precise predictions of transition onset location and peak heat flux of a wide range of hypersonic Transitional Boundary Layers(TrBL)around straight cone at zero incidence,to an unprecedented accuracy as validated by over 70 measurements for varying five crucial influential factors(Mach number,temperature ratio,cone half angle,nose Reynolds number and noise level).The results demonstrate the universality of the postulated multi-regime similarity structure,in characterizing not only the spatial non-uniform distribution of the eddy viscosity in hypersonic TrBL on cone,but also the dependence of the transition onset location on the five influential factors.The latter yields a novel correlation formula for transition center Reynolds number which takes similar functional form as the SL function within the symmetry approach.It is concluded that the SED-SL model simulates TrBL around cone with uniformly high accuracy,and then points out to an optimistic alternative way to construct hypersonic transition model.
基金Supported by the National Nature Science Foundation of China(11071001)Supported by the Key Program of Ministry of Education of China(205068)
文摘In this paper, we consider the positive solutions of fractional three-point boundary value problem of the form Dο^α＋u（t）＋f（t,u（t）,u＇（t）,…,u^（n-3）（5）,u^（n-2）（t））=0,u^（i）（0）=0,0≤i≤n-2,u^（n-2）（1）-βu^（n-2）（ξ）=0,where 0〈t〈1,n-1〈α≤n,n≥2,ξ Е（0,1）,βξ^a-n〈1. We first transform it into another equivalent boundary value problem. Then, we derive the Green＇s function for the equivalent boundary value problem and show that it satisfies certain properties. At last, by using some fixed-point theorems, we obtain the existence of positive solution for this problem. Example is given to illustrate the effectiveness of our result.
基金Natural Scince Foundation of China and Foundation for University Key Teacher by the Ministry of Education
文摘The existence of positive solutions for second order m-point boundary value problemx″-q(t)f(x,x′)x′=0, x(0)= m i=2 b ix(ξ i),x′(1)=αx′(0)are investigated,where ξ i,b i and α are constants satisfying 0=ξ 1<ξ 2<...<ξ m-1 <ξ m=1,b i≥0 for i=2,...,m with β∶= m i=2 b i∈[0,1), and α>1. Our approach is based on the fixed point theorem in cones.
基金conducted under the 973 Program of China (No. 2012CB822003)the National Natural Science Foundation of China (Nos. 41402007, 41602023)the Fundamental Research Funds for the Central Universities (Lzujbky-2014-132)
文摘Fossil Taiwania was discovered from the Lower Cretaceous Yixian Formation of Lingyuan City, western Liaoning Province, Northeast China. It is identified as a new species, Taiwania lingyuanensis sp. nov.. The present specimen is preserved as impressions with well defined leaf shoots system and reproductive structures. Leaves are dimorphic, spirally and imbricately arranged. They are scale-like on the main and cone-bearing branchlets, and subulate to falcate-subulate on the juvenile or sterile shoots. The seed cones are singly elliptic, ovate or elongate-ovate and terminally borne on ultimate shoots, bearing 22–24 scale-bracts complexes imbricately and helically arranged around the cone axis, the bracts are broadovate, rhomboidal or hexagonal with entire margins. Both the leafy shoots morphology and reproductive structures are similar to extant Taiwania. Furthermore, geological distribution and molecular biological evidences support that Taiwania is probably originated from the eastern Asia at least in the Early Cretaceous and widely distributed in the North Hemisphere thereafter.
基金supported by the National Natural Science Foundation of China(No.11361064)the project No.174024 of the Ministry of Education,Science and Technological Department of the Republic of Serbia
文摘In this paper, we introduce the concept of generalized g-quasi-contractions in the setting of cone b-metric spaces over Banach algebras. By omitting the assump- tion of normality we establish common fixed point theorems for the generalized g- quasi-contractions with the spectral radius r（λ） of the g-quasi-contractive constant vector λ satisfying r（λ） ∈[0,1） in the setting of cone b-metric spaces over Banach al- gebras, where the coefficient s satisfies s ≥ 1. The main results generalize, extend and unify several well-known comparable results in the literature.
