How to mine valuable information from massive multisource heterogeneous data and identify the intention of aerial targets is a major research focus at present. Aiming at the longterm dependence of air target intention...How to mine valuable information from massive multisource heterogeneous data and identify the intention of aerial targets is a major research focus at present. Aiming at the longterm dependence of air target intention recognition, this paper deeply explores the potential attribute features from the spatiotemporal sequence data of the target. First, we build an intelligent dynamic intention recognition framework, including a series of specific processes such as data source, data preprocessing,target space-time, convolutional neural networks-bidirectional gated recurrent unit-atteneion (CBA) model and intention recognition. Then, we analyze and reason the designed CBA model in detail. Finally, through comparison and analysis with other recognition model experiments, our proposed method can effectively improve the accuracy of air target intention recognition,and is of significance to the commanders’ operational command and situation prediction.展开更多
Hydrogen peroxide(H_(2)O_(2))has gained widespread attention as a versatile oxidant and a mild disin-fectant.Here,an electrostatic self-assembly method is applied to couple ZnSe quantum dots(QDs)with a flower-like cov...Hydrogen peroxide(H_(2)O_(2))has gained widespread attention as a versatile oxidant and a mild disin-fectant.Here,an electrostatic self-assembly method is applied to couple ZnSe quantum dots(QDs)with a flower-like covalent organic framework(COF)to form a step-scheme(S-scheme)photocata-lyst for H_(2)O_(2)production.The as-prepared S-scheme photocatalyst exhibits a broad light absorption range with an edge at 810 nm owing to the synergistic effect between the ZnSe QDs and COF.The S-scheme charge-carrier transfer mechanism is validated by performing Fermi level calculations and in-situ X-ray photoelectron and femtosecond transient absorption spectroscopies.Photolumi-nescence,time-resolved photoluminescence,photocurrent response,electrochemical impedance spectroscopy,and electron paramagnetic resonance results show that the S-scheme heterojunction not only promotes charge carrier separation but also boosts the redox ability,resulting in enhanced photocatalytic performance.Remarkably,a 10%-ZnSe QD/COF has excellent photocatalytic H_(2)O_(2)-production activity,and the optimal S-scheme composite with ethanol as the hole scavenger yields a H_(2)O_(2)-production rate of 1895 mol g^(-1)h^(-1).This study presents an example of a high-performance organic/inorganic S-scheme photocatalyst for H_(2)O_(2)production.展开更多
Spatial structural features of middle- and small-sized mountainous cities in China were analyzed. Taking Shangluo City for example, problems in the spatial planning of middle- and small-sized mountainous cities were e...Spatial structural features of middle- and small-sized mountainous cities in China were analyzed. Taking Shangluo City for example, problems in the spatial planning of middle- and small-sized mountainous cities were explored, it was stressed that local characteristics should be respected to make plans reasonably, and handle the spatial transition between urban and rural areas properly, so as not to lose the originality of rural areas during the urbanization. The study aimed at providing useful experience for the urbanization.展开更多
The walnut industry in Shangluo City is evaluated based on SWOT. The internal advantage,disadvantage,external opportunities and threats to the walnut industry are found out. In the end,suggestions towards the developm...The walnut industry in Shangluo City is evaluated based on SWOT. The internal advantage,disadvantage,external opportunities and threats to the walnut industry are found out. In the end,suggestions towards the development of walnut industry in Shangluo City are put forward.展开更多
To scientifically and effectively conduct comprehensive control of water sources to achieve water safety,the importance,main steps and plan of comprehensive control of ecological environment in water sources were anal...To scientifically and effectively conduct comprehensive control of water sources to achieve water safety,the importance,main steps and plan of comprehensive control of ecological environment in water sources were analyzed on the basis of analyzing the development and protection process of foreign water sources.The results show that for the comprehensive control of water sources,it is needed to pay attention to the accurate grasp of the current environmental quality of water sources and carefully analyze the problems in the ecological environment of water sources.Besides,it is necessary to ensure the water quality and quantity of sources,focus on the implementation of environmental remediation and ecological restoration,implement regional protection of water sources,and combine engineering and non-engineering measures to take comprehensive control of environmental problems.展开更多
In this paper, a new filled function with only one parameter is proposed. The main advantages of the new filled function are that it not only can be analyzed easily, but also can be approximated uniformly by a continu...In this paper, a new filled function with only one parameter is proposed. The main advantages of the new filled function are that it not only can be analyzed easily, but also can be approximated uniformly by a continuously differentiable function. Thus, a minimizer of the proposed filled function can be obtained easily by using a local optimization algorithm. The obtained minimizer is taken as the initial point to minimize the objective function and a better minimizer will be found. By repeating the above processes, we will find a global minimizer at last. The results of numerical experiments show that the new proposed filled function method is effective.展开更多
In this study, pentlandite was selectively separated from serpentine using magnetic coating technology by adjusting and optimizing pH, stirring speeds, magnetic field intensities, and dosages of sodium hexametaphospha...In this study, pentlandite was selectively separated from serpentine using magnetic coating technology by adjusting and optimizing pH, stirring speeds, magnetic field intensities, and dosages of sodium hexametaphosphate(SHMP) and sodium oleate(SO). A magnetic concentrate with Ni grade of 20.8% and Ni recovery of 80.5% was attained under the optimized operating conditions. Considering the above, the adsorption behaviors of SHMP and SO and the surface properties of minerals after the magnetic coating were studied by Fourier transform infrared(FTIR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM). The results show that magnetite was preferentially coated on the pentlandite surfaces and sparingly coated on the serpentine surfaces in the presence of SHMP and SO. Furthermore, calculations by Derjaguin-Landau-Verwey-Overbeek(DLVO) theory indicate that the preferential adsorption of magnetite on the pentlandite surfaces is due to the presence of a hydrophobic interaction between the magnetite and pentlandite, which is much stronger than the interaction between magnetite and serpentine.展开更多
Modeling the oxygen-18 in precipitation based on regional topography and meteorological factors is helpful to constrain missing isotopic data in some regions that is required for many paleoclimate,eco-hydrological and...Modeling the oxygen-18 in precipitation based on regional topography and meteorological factors is helpful to constrain missing isotopic data in some regions that is required for many paleoclimate,eco-hydrological and atmospheric circulation studies.Therefore,the relationship betweenδ18Oin precipitation(δ18OPPT)and the affecting factors need to be thoroughly understood.We present a model considering the combined effects of temperature,altitude,and latitude on the spatial variability of annual average of stable isotopes in precipitation across China.This new model performed significantly better(P<0.05)than the widely used Farquhar and Bowen&Wilkinsonmodels.Our model allows modelling the spatial distribution of isotopes in precipitation depending on temperature variation.The residuals of presented model did not significantly correlate with altitude.Based on the model and residuals,a high-resolution map of annual averageδ18Opptacross China was generated.δ18OPPTdecreased from low toward high latitudes and from low towards high altitudes area.The model application provides important information forancient climate,hydrological cycle and water vapor sources studies.展开更多
As the water source of central route of China's south-to-north water diversion project,the Danjiang River Basin shoulders a major historical mission.Therefore,it is imperative to perform ecological restoration for...As the water source of central route of China's south-to-north water diversion project,the Danjiang River Basin shoulders a major historical mission.Therefore,it is imperative to perform ecological restoration for control of water and soil loss and improvement of the ecological environment.In this paper,based on the current status of research on ecological restoration at home and abroad,the layout principles of ecological restoration and functional traits of plants were analyzed.Afterwards,the principles and methods of plant selection in ecological restoration engineering were determined,and the ecological allocation plan of plants in ecological restoration for soil and water conservation in the Danjiang River Basin was proposed according to the specific conditions of the Danjiang River Basin.It provides reference for the ecological restoration and the sustainable development of the ecological environment in the Danjiang River Basin,and can also be used in other similar projects.展开更多
Based on the backstepping design of smooth systems, we developed a new control law to achieve chaos control for a vibro-impact system. In our control strategy, a novel and effective controller is designed such that th...Based on the backstepping design of smooth systems, we developed a new control law to achieve chaos control for a vibro-impact system. In our control strategy, a novel and effective controller is designed such that the output of the vibro-impact system can track any desired trajectory in its domain. The single-degree-of-freedom vibro-impact system is taken as an example to show this control procedure. Numerical simulations are provided to verify the effectiveness of the proposed method.展开更多
This paper derives some sufficient conditions for the stabilization of Lorenz system with stochastic impulsive control. The estimate of the upper bound of impulse interval for asymptotically stable control is obtained...This paper derives some sufficient conditions for the stabilization of Lorenz system with stochastic impulsive control. The estimate of the upper bound of impulse interval for asymptotically stable control is obtained. Some differences between the system with stochastic impulsive control and with deterministic impulsive control are presented. Computer simulation is given to show the effectiveness of the proposed method.展开更多
Numerical simulations based on a new regularized phase-field model were presented, to simulate the solidification of hexagonal close-packed materials with strong interfacial energy anisotropies. Results show that the ...Numerical simulations based on a new regularized phase-field model were presented, to simulate the solidification of hexagonal close-packed materials with strong interfacial energy anisotropies. Results show that the crystal grows into facet dendrites,displaying six-fold symmetry. The size of initial crystals has an effect on the branching-off of the principal branch tip along the<100> direction, which is eliminated by setting the b/a(a and b are the semi-major and semi-minor sizes in the initial elliptical crystals, respectively) value to be less than or equal to 1. With an increase in the undercooling value, the equilibrium morphology of the crystal changes from a star-like shape to facet dendrites without side branches. The steady-state tip velocity increases exponentially when the dimensionless undercooling is below the critical value. With a further increase in the undercooling value, the equilibrium morphology of the crystal grows into a developed side-branch structure, and the steady-state tip velocity of the facet dendrites increases linearly. The facet dendrite growth has controlled diffusion and kinetics.展开更多
To improve the resource utilization of recycled aggregate concrete(RAC)and make use of the unique pozzolanic activation characteristics of iron ore tailing(IOT),the constitutive curves of tailing recycled concrete(TRC...To improve the resource utilization of recycled aggregate concrete(RAC)and make use of the unique pozzolanic activation characteristics of iron ore tailing(IOT),the constitutive curves of tailing recycled concrete(TRC)before and after carbonization were analyzed theoretically,experimentally and microscopically.Firstly,according to the experimental data,the damage constitutive and related damage parameters of TRC were theoretically established by Weibull probability distribution function.Secondly,the comprehensive damage parameter b under different working conditions was studied.Finally,the damage mechanism was formed by EDS and SEM.The results showed that the damage constitutive model based on Weibull probability distribution function was in good agreement with the experimental results.Under each carbonization period,the b first decreased and then rose with the increase of tailings content.When its content was 30%,the b values of TRC were minimized,which were 22.14%,20.99%,25.39%lower than those of NAC,and 41.09%,34.89%,35.44%lower than those of RAC,indicating that IOT had a relatively good optimization effect on the constitutive curve of RAC.The microscopic analysis results also proved that the IOT addition with a proper amount would improve the matrix structure of RAC and increased its compactness,but when the content was higher,it would also cause harmful cracks in its matrix structure and reduced its density.Therefore,the optimal tailing content was about 30%.This paper provided a new method for damage constitutive calculation and analysis of TRC before and after carbonization.展开更多
[N-(Propionic acid)] terephthalal acyl dihydrazone(H4L) was synthesized and characterized by element analysis, IR, 1H NMR and MS. The theoretical studies on H4L were carried out at HF/6-31+G(d) and B3LYP/ 6-3 I...[N-(Propionic acid)] terephthalal acyl dihydrazone(H4L) was synthesized and characterized by element analysis, IR, 1H NMR and MS. The theoretical studies on H4L were carried out at HF/6-31+G(d) and B3LYP/ 6-3 I+G(oD levels. The main decomposition stage of it was studied with IR track. The kinetic parameters[the apparent activation energy(Ea) and pre-exponential constant(A) of the first and second stages of decomposition reaction] were obtained by Kissinger and Ozawa's methods. Furthermore, the antimicrobial activity of HaL against wheat rust was investigated by spore sprout method.展开更多
Duo to culture differences between China and The West,translators inevitably come across with culture deficiency in the process of drama translation.Therefore,culture construction of drama translation is needed.Base o...Duo to culture differences between China and The West,translators inevitably come across with culture deficiency in the process of drama translation.Therefore,culture construction of drama translation is needed.Base on this,the thesis introduces the inter textual,intratextual and extratextual mode to the translations of Lao She’s Tea House to study the construction of culture information in Tea House,which can deal with the untranslatability problem caused by the culture deficiency,give a new sight to drama translation,promote the culture communication between China and The West.展开更多
Background:Cotton is the world’s largest and most important source of renewable natural fiber.BEL1-like homeodomain(BLH)genes are ubiquitous in plants and have been reported to contribute to plant development.However...Background:Cotton is the world’s largest and most important source of renewable natural fiber.BEL1-like homeodomain(BLH)genes are ubiquitous in plants and have been reported to contribute to plant development.However,there is no comprehensive characterization of this gene family in cotton.In this study,32,16,and 18 BLH genes were identified from the G.hirsutum,G.arboreum,and G.raimondii genome,respectively.In addition,we also studied the phylogenetic relationships,chromosomal location,gene structure,and gene expression patterns of the BLH genes.Results:The results indicated that these BLH proteins were divided into seven distinct groups by phylogenetic analysis.Among them,25 members were assigned to 15 chromosomes.Furthermore,gene structure,chromosomal location,conserved motifs,and expression level of BLH genes were investigated in G.hirsutum.Expression profiles analysis showed that four genes(GhBLH1_3,GhBLH1_4,GhBLH1_5,and GhBLH1_6)from BLH1 subfamily were highly expressed during the fiber cell elongation period.The expression levels of these genes were significantly induced by gibberellic acid and brassinosteroid,but not auxin.Exogenous application of gibberellic acid significantly enhanced GhBLH1_3,GhBLH1_4,and GhBLH1_5 transcripts.Expression levels of GhBLH1_3 and GhBLH1_4 genes were significantly increased under brassinosteroid treatment.Conclusions:The BLH gene family plays a very important role in many biological processes during plant growth and development.This study deepens our understanding of the role of the GhBLH1 gene involved in fiber development and will help us in breeding better cotton varieties in the future.展开更多
Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numer...Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam slope.The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water levels.The safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and fell.The water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level fluctuations.The desorption SWCC is suggested for engineering design.Furthermore,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.展开更多
The Tibetan Plateau(TP)is one of the most sensitive areas and is more susceptible to climate change than other regions in China.The TP also experiences extremely frequent light precipitation events compared to precipi...The Tibetan Plateau(TP)is one of the most sensitive areas and is more susceptible to climate change than other regions in China.The TP also experiences extremely frequent light precipitation events compared to precipitation of other intensities.However,the definition,influencing factors,and characteristics of light precipitation in the TP have not been accurately explained.This study investigated the variation characteristics of light precipitation with intensities(Pre)of 0.1-10.0 mm/d based on climate data from 53 meteorological stations over the central and eastern TP from 1961 to 2019.For detailed analysis,light precipitation events were classified into five grades:G1[0.1-2.0 mm/d),G2[2.0-4.0 mm/d),G3[4.0-6.0 mm/d),G4[6.0-8.0 mm/d),and G5[8.0-10.0 mm/d).The results showed that both the amount of precipitation and number of precipitation days had increased significantly at rates of 4.0-6.0 mm/10 yr and 2.0-4.0 d/10 yr,respectively,and most precipitation events were of low intensity(0.1≤Pre<2.0 mm/d).Light precipitation events mainly occurred in the southeast of the study area,and it showed an increasing trend from the northwest to the southeast.Abrupt changes in light precipitation primarily occurred in the 1980 s.A comprehensive time series analysis using the Mann-Kendall test and Morlet wavelet was performed to characterize the abrupt changes and cycles of light precipitation.During the study period,the main periods of light precipitation corresponded to the 6 yr cycle,with obvious periodic oscillation characteristics,and this cycle coexisted with cycles of other scales.Significant correlations were observed between the amount of light precipitation and temperature over the study area.The findings will enhance our understanding of changes in light precipitation in the TP and provide Scientific basis for the definition of light precipitation in the future.展开更多
Optomagnetic multifunctional composite based on upconversion luminescence nanomaterial is regarded as a promising strategy for bioimaging,disease diagnosis and targeted delivery of drugs.To explore a mesoporous nanost...Optomagnetic multifunctional composite based on upconversion luminescence nanomaterial is regarded as a promising strategy for bioimaging,disease diagnosis and targeted delivery of drugs.To explore a mesoporous nanostructure with excellent water dispersibility and high drug-loading capacity,a novel nanorattle-structured Fe3O4@SiO2@NaYF4:Yb,Er magnetic upconversion nanorattle(MUCNR)was successfully designed by using Fe3O4 as core and NaYF4:Yb,Er nanocrystals as shell.The microstructures and crystal phase of the as-prepared MUCNRs were evaluated by transmission electron microscopy,Xray powder diffraction and N2 adsorption/desorption isotherms.The Kirkendall effect was adapted to explain the formation mechanism of the MUCNRs.The loading content and encapsulation efficiency of doxorubicin hydrochloride(DOX)could reach as high as 18.2%and 60.7%,respectively.Moreover,the DOX loading MUCNR(DOX-MUCNR)system showed excellent sustained drug release and strong p Hdependent performance,which was conducive to drug release at the slightly acidic microenvironment of tumor.Microcalorimetry was used to quantify the interactions between the carrier structure and drug release rate directly.The heat release rates in the heat-flow diagrams are basically consistent with the DOX release rate,thereby showing that microcalorimetry assay not only provides a unique thermodynamic explanation for the structure–activity relationship of Fe3O4@SiO2@NaYF4:Yb,Er MUCNRs but also provides powerful guidance to avoid the blind selection or design of drug carriers.Therefore,our work firmly provided a comprehensive perspective for using Fe3O4@SiO2@NaYF4:Yb,Er MUCNRs as a remarkable magnetic targeted drug carrier.展开更多
基金supported by the National Natural Science Foundation of China (61502523)。
文摘How to mine valuable information from massive multisource heterogeneous data and identify the intention of aerial targets is a major research focus at present. Aiming at the longterm dependence of air target intention recognition, this paper deeply explores the potential attribute features from the spatiotemporal sequence data of the target. First, we build an intelligent dynamic intention recognition framework, including a series of specific processes such as data source, data preprocessing,target space-time, convolutional neural networks-bidirectional gated recurrent unit-atteneion (CBA) model and intention recognition. Then, we analyze and reason the designed CBA model in detail. Finally, through comparison and analysis with other recognition model experiments, our proposed method can effectively improve the accuracy of air target intention recognition,and is of significance to the commanders’ operational command and situation prediction.
文摘Hydrogen peroxide(H_(2)O_(2))has gained widespread attention as a versatile oxidant and a mild disin-fectant.Here,an electrostatic self-assembly method is applied to couple ZnSe quantum dots(QDs)with a flower-like covalent organic framework(COF)to form a step-scheme(S-scheme)photocata-lyst for H_(2)O_(2)production.The as-prepared S-scheme photocatalyst exhibits a broad light absorption range with an edge at 810 nm owing to the synergistic effect between the ZnSe QDs and COF.The S-scheme charge-carrier transfer mechanism is validated by performing Fermi level calculations and in-situ X-ray photoelectron and femtosecond transient absorption spectroscopies.Photolumi-nescence,time-resolved photoluminescence,photocurrent response,electrochemical impedance spectroscopy,and electron paramagnetic resonance results show that the S-scheme heterojunction not only promotes charge carrier separation but also boosts the redox ability,resulting in enhanced photocatalytic performance.Remarkably,a 10%-ZnSe QD/COF has excellent photocatalytic H_(2)O_(2)-production activity,and the optimal S-scheme composite with ethanol as the hole scavenger yields a H_(2)O_(2)-production rate of 1895 mol g^(-1)h^(-1).This study presents an example of a high-performance organic/inorganic S-scheme photocatalyst for H_(2)O_(2)production.
文摘Spatial structural features of middle- and small-sized mountainous cities in China were analyzed. Taking Shangluo City for example, problems in the spatial planning of middle- and small-sized mountainous cities were explored, it was stressed that local characteristics should be respected to make plans reasonably, and handle the spatial transition between urban and rural areas properly, so as not to lose the originality of rural areas during the urbanization. The study aimed at providing useful experience for the urbanization.
基金Supported by the "Twelve-Fifth" Education and Science Planning Subject in Shaanxi(SGH12442)Shangluo College Supporting Project(13sky005)Education and Teaching Reform of Shangluo College(13jyjx104)
文摘The walnut industry in Shangluo City is evaluated based on SWOT. The internal advantage,disadvantage,external opportunities and threats to the walnut industry are found out. In the end,suggestions towards the development of walnut industry in Shangluo City are put forward.
基金Supported by the Innovation and Entrepreneurship Training Program for College Students of Shaanxi Province in 2022(S202211396028)Innovation and Entrepreneurship Training Program for College Students of Shaanxi Province in 2021(S202111396068).
文摘To scientifically and effectively conduct comprehensive control of water sources to achieve water safety,the importance,main steps and plan of comprehensive control of ecological environment in water sources were analyzed on the basis of analyzing the development and protection process of foreign water sources.The results show that for the comprehensive control of water sources,it is needed to pay attention to the accurate grasp of the current environmental quality of water sources and carefully analyze the problems in the ecological environment of water sources.Besides,it is necessary to ensure the water quality and quantity of sources,focus on the implementation of environmental remediation and ecological restoration,implement regional protection of water sources,and combine engineering and non-engineering measures to take comprehensive control of environmental problems.
文摘In this paper, a new filled function with only one parameter is proposed. The main advantages of the new filled function are that it not only can be analyzed easily, but also can be approximated uniformly by a continuously differentiable function. Thus, a minimizer of the proposed filled function can be obtained easily by using a local optimization algorithm. The obtained minimizer is taken as the initial point to minimize the objective function and a better minimizer will be found. By repeating the above processes, we will find a global minimizer at last. The results of numerical experiments show that the new proposed filled function method is effective.
基金financially supported by the National Natural Science Foundation of China(No.51704057)the China Postdoctoral Science Foundation(No.2017M621153)+2 种基金the Postdoctoral Science Foundation of Northeastern University(No.20170312)the Fundamental Research Funds for the Central Universities(No.N170104018)the Open Fund Project of Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources,China(No.2017SKY-WK012)
文摘In this study, pentlandite was selectively separated from serpentine using magnetic coating technology by adjusting and optimizing pH, stirring speeds, magnetic field intensities, and dosages of sodium hexametaphosphate(SHMP) and sodium oleate(SO). A magnetic concentrate with Ni grade of 20.8% and Ni recovery of 80.5% was attained under the optimized operating conditions. Considering the above, the adsorption behaviors of SHMP and SO and the surface properties of minerals after the magnetic coating were studied by Fourier transform infrared(FTIR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM). The results show that magnetite was preferentially coated on the pentlandite surfaces and sparingly coated on the serpentine surfaces in the presence of SHMP and SO. Furthermore, calculations by Derjaguin-Landau-Verwey-Overbeek(DLVO) theory indicate that the preferential adsorption of magnetite on the pentlandite surfaces is due to the presence of a hydrophobic interaction between the magnetite and pentlandite, which is much stronger than the interaction between magnetite and serpentine.
基金financially supported by National Natural Science Foundation of China(41790431 and 41471188)the Innovative Talents Promotion Plan in Shaanxi Province(2017-KJXX-74)the CAS “Light of West China” Program
文摘Modeling the oxygen-18 in precipitation based on regional topography and meteorological factors is helpful to constrain missing isotopic data in some regions that is required for many paleoclimate,eco-hydrological and atmospheric circulation studies.Therefore,the relationship betweenδ18Oin precipitation(δ18OPPT)and the affecting factors need to be thoroughly understood.We present a model considering the combined effects of temperature,altitude,and latitude on the spatial variability of annual average of stable isotopes in precipitation across China.This new model performed significantly better(P<0.05)than the widely used Farquhar and Bowen&Wilkinsonmodels.Our model allows modelling the spatial distribution of isotopes in precipitation depending on temperature variation.The residuals of presented model did not significantly correlate with altitude.Based on the model and residuals,a high-resolution map of annual averageδ18Opptacross China was generated.δ18OPPTdecreased from low toward high latitudes and from low towards high altitudes area.The model application provides important information forancient climate,hydrological cycle and water vapor sources studies.
基金Supported by the Basic Operation Guarantee Foundation for the Connotation Development of Universities(2016JB001)Science and Technology Planning Project of Shangluo City(SK2015-33)
文摘As the water source of central route of China's south-to-north water diversion project,the Danjiang River Basin shoulders a major historical mission.Therefore,it is imperative to perform ecological restoration for control of water and soil loss and improvement of the ecological environment.In this paper,based on the current status of research on ecological restoration at home and abroad,the layout principles of ecological restoration and functional traits of plants were analyzed.Afterwards,the principles and methods of plant selection in ecological restoration engineering were determined,and the ecological allocation plan of plants in ecological restoration for soil and water conservation in the Danjiang River Basin was proposed according to the specific conditions of the Danjiang River Basin.It provides reference for the ecological restoration and the sustainable development of the ecological environment in the Danjiang River Basin,and can also be used in other similar projects.
基金Supported by the National Natural Science Foundation of China under Grant No 10872165. Although this work only gives the control scheme for the SDOF vibro-impact system, we think that this control method can be used to achieve chaos control in some other non-smooth systems because of the identical structures and the similar expressions, and the controllers can be obtained by the similar process shown here.
文摘Based on the backstepping design of smooth systems, we developed a new control law to achieve chaos control for a vibro-impact system. In our control strategy, a novel and effective controller is designed such that the output of the vibro-impact system can track any desired trajectory in its domain. The single-degree-of-freedom vibro-impact system is taken as an example to show this control procedure. Numerical simulations are provided to verify the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China (Grant No. 10872165)
文摘This paper derives some sufficient conditions for the stabilization of Lorenz system with stochastic impulsive control. The estimate of the upper bound of impulse interval for asymptotically stable control is obtained. Some differences between the system with stochastic impulsive control and with deterministic impulsive control are presented. Computer simulation is given to show the effectiveness of the proposed method.
基金Project(10834015) supported by the National Natural Science Foundation of ChinaProject(12SKY01-1) supported by the Doctoral Fund of Shangluo University,ChinaProject(14JK1223) supported by the Scientific Research Program of Shaanxi Provincial Education Department,China
文摘Numerical simulations based on a new regularized phase-field model were presented, to simulate the solidification of hexagonal close-packed materials with strong interfacial energy anisotropies. Results show that the crystal grows into facet dendrites,displaying six-fold symmetry. The size of initial crystals has an effect on the branching-off of the principal branch tip along the<100> direction, which is eliminated by setting the b/a(a and b are the semi-major and semi-minor sizes in the initial elliptical crystals, respectively) value to be less than or equal to 1. With an increase in the undercooling value, the equilibrium morphology of the crystal changes from a star-like shape to facet dendrites without side branches. The steady-state tip velocity increases exponentially when the dimensionless undercooling is below the critical value. With a further increase in the undercooling value, the equilibrium morphology of the crystal grows into a developed side-branch structure, and the steady-state tip velocity of the facet dendrites increases linearly. The facet dendrite growth has controlled diffusion and kinetics.
基金This work was funded by the Natural Science Foundation of China(No.51678480)Ministry of Education Cooperative Education Project(201802308007)+3 种基金Innovation Capability Support Program of Shaanxi(2020PT-038)Henan Province Key Scientific Research Projects of Colleges and Universities(19A560016)Henan Province Key Projects of Science and Technology(192102310277,182102310834)Scientific Research Projects of Shaanxi Education Department(16JK1244).
文摘To improve the resource utilization of recycled aggregate concrete(RAC)and make use of the unique pozzolanic activation characteristics of iron ore tailing(IOT),the constitutive curves of tailing recycled concrete(TRC)before and after carbonization were analyzed theoretically,experimentally and microscopically.Firstly,according to the experimental data,the damage constitutive and related damage parameters of TRC were theoretically established by Weibull probability distribution function.Secondly,the comprehensive damage parameter b under different working conditions was studied.Finally,the damage mechanism was formed by EDS and SEM.The results showed that the damage constitutive model based on Weibull probability distribution function was in good agreement with the experimental results.Under each carbonization period,the b first decreased and then rose with the increase of tailings content.When its content was 30%,the b values of TRC were minimized,which were 22.14%,20.99%,25.39%lower than those of NAC,and 41.09%,34.89%,35.44%lower than those of RAC,indicating that IOT had a relatively good optimization effect on the constitutive curve of RAC.The microscopic analysis results also proved that the IOT addition with a proper amount would improve the matrix structure of RAC and increased its compactness,but when the content was higher,it would also cause harmful cracks in its matrix structure and reduced its density.Therefore,the optimal tailing content was about 30%.This paper provided a new method for damage constitutive calculation and analysis of TRC before and after carbonization.
基金Supported by the Shaanxi Provincial Project of the Technology and Plan,China(No.2007K02-11)the Project of Education Committee of Shaanxi Province,China(No.2011JG04)the Shaanxi Provincial Science and Technology Project,China(No.08ZDKG-268)
文摘[N-(Propionic acid)] terephthalal acyl dihydrazone(H4L) was synthesized and characterized by element analysis, IR, 1H NMR and MS. The theoretical studies on H4L were carried out at HF/6-31+G(d) and B3LYP/ 6-3 I+G(oD levels. The main decomposition stage of it was studied with IR track. The kinetic parameters[the apparent activation energy(Ea) and pre-exponential constant(A) of the first and second stages of decomposition reaction] were obtained by Kissinger and Ozawa's methods. Furthermore, the antimicrobial activity of HaL against wheat rust was investigated by spore sprout method.
文摘Duo to culture differences between China and The West,translators inevitably come across with culture deficiency in the process of drama translation.Therefore,culture construction of drama translation is needed.Base on this,the thesis introduces the inter textual,intratextual and extratextual mode to the translations of Lao She’s Tea House to study the construction of culture information in Tea House,which can deal with the untranslatability problem caused by the culture deficiency,give a new sight to drama translation,promote the culture communication between China and The West.
基金the State Key Laboratory of Cotton Biology Open Fund(CB2019A03,2019A09 and CB2020A12)the National Natural Science Foundation of China(31872175)+2 种基金the Fundamental Research Funds for the Central Universities(GK202002005 and GK202001004)Natural Science Basic Research Plan in Shaanxi Province of China(2018JZ3006 and 2019JQ-062),Shaanxi Youth Entrusted Talents Program(20190205),Shaanxi Postdoctoral Project(2018BSHYDZZ76)Young Elite Scientists Sponsorship Program by CAST(2019-2021QNRC001).
文摘Background:Cotton is the world’s largest and most important source of renewable natural fiber.BEL1-like homeodomain(BLH)genes are ubiquitous in plants and have been reported to contribute to plant development.However,there is no comprehensive characterization of this gene family in cotton.In this study,32,16,and 18 BLH genes were identified from the G.hirsutum,G.arboreum,and G.raimondii genome,respectively.In addition,we also studied the phylogenetic relationships,chromosomal location,gene structure,and gene expression patterns of the BLH genes.Results:The results indicated that these BLH proteins were divided into seven distinct groups by phylogenetic analysis.Among them,25 members were assigned to 15 chromosomes.Furthermore,gene structure,chromosomal location,conserved motifs,and expression level of BLH genes were investigated in G.hirsutum.Expression profiles analysis showed that four genes(GhBLH1_3,GhBLH1_4,GhBLH1_5,and GhBLH1_6)from BLH1 subfamily were highly expressed during the fiber cell elongation period.The expression levels of these genes were significantly induced by gibberellic acid and brassinosteroid,but not auxin.Exogenous application of gibberellic acid significantly enhanced GhBLH1_3,GhBLH1_4,and GhBLH1_5 transcripts.Expression levels of GhBLH1_3 and GhBLH1_4 genes were significantly increased under brassinosteroid treatment.Conclusions:The BLH gene family plays a very important role in many biological processes during plant growth and development.This study deepens our understanding of the role of the GhBLH1 gene involved in fiber development and will help us in breeding better cotton varieties in the future.
基金funded by the Key R&D Program of Science and Technology Bureau of Shangluo City(Grant No.2020-Z-0111)Scientific Research Program of Science and Technology Department of Shaanxi Province(Grant No.2021JQ-844).
文摘Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam slope.The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water levels.The safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and fell.The water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level fluctuations.The desorption SWCC is suggested for engineering design.Furthermore,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.
基金Under the auspices of the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK040)Key Technologies Research and Development Program of Shaanxi Province(No.2021ZDLSF05-02)+2 种基金The National Natural Science Foundation of China(No.42072208,42101100,41901129)The Fundamental Research Funds for the Central Universities(No.GK202001003)Natural Science Foundation of Shaanxi Province(No.2021JQ-313)。
文摘The Tibetan Plateau(TP)is one of the most sensitive areas and is more susceptible to climate change than other regions in China.The TP also experiences extremely frequent light precipitation events compared to precipitation of other intensities.However,the definition,influencing factors,and characteristics of light precipitation in the TP have not been accurately explained.This study investigated the variation characteristics of light precipitation with intensities(Pre)of 0.1-10.0 mm/d based on climate data from 53 meteorological stations over the central and eastern TP from 1961 to 2019.For detailed analysis,light precipitation events were classified into five grades:G1[0.1-2.0 mm/d),G2[2.0-4.0 mm/d),G3[4.0-6.0 mm/d),G4[6.0-8.0 mm/d),and G5[8.0-10.0 mm/d).The results showed that both the amount of precipitation and number of precipitation days had increased significantly at rates of 4.0-6.0 mm/10 yr and 2.0-4.0 d/10 yr,respectively,and most precipitation events were of low intensity(0.1≤Pre<2.0 mm/d).Light precipitation events mainly occurred in the southeast of the study area,and it showed an increasing trend from the northwest to the southeast.Abrupt changes in light precipitation primarily occurred in the 1980 s.A comprehensive time series analysis using the Mann-Kendall test and Morlet wavelet was performed to characterize the abrupt changes and cycles of light precipitation.During the study period,the main periods of light precipitation corresponded to the 6 yr cycle,with obvious periodic oscillation characteristics,and this cycle coexisted with cycles of other scales.Significant correlations were observed between the amount of light precipitation and temperature over the study area.The findings will enhance our understanding of changes in light precipitation in the TP and provide Scientific basis for the definition of light precipitation in the future.
基金supported by the Key Research and Development Plan of Shaanxi Province(2020GY-313)the Specialized Research Fund of Education Department of Shaanxi Province(19JK0255)+1 种基金the Specialized Scientific Research Fund Projects of Academician Shengyong Zhang(18YSZX001)the Science and Technology Innovation Team of Shangluo University(20SCX02)。
文摘Optomagnetic multifunctional composite based on upconversion luminescence nanomaterial is regarded as a promising strategy for bioimaging,disease diagnosis and targeted delivery of drugs.To explore a mesoporous nanostructure with excellent water dispersibility and high drug-loading capacity,a novel nanorattle-structured Fe3O4@SiO2@NaYF4:Yb,Er magnetic upconversion nanorattle(MUCNR)was successfully designed by using Fe3O4 as core and NaYF4:Yb,Er nanocrystals as shell.The microstructures and crystal phase of the as-prepared MUCNRs were evaluated by transmission electron microscopy,Xray powder diffraction and N2 adsorption/desorption isotherms.The Kirkendall effect was adapted to explain the formation mechanism of the MUCNRs.The loading content and encapsulation efficiency of doxorubicin hydrochloride(DOX)could reach as high as 18.2%and 60.7%,respectively.Moreover,the DOX loading MUCNR(DOX-MUCNR)system showed excellent sustained drug release and strong p Hdependent performance,which was conducive to drug release at the slightly acidic microenvironment of tumor.Microcalorimetry was used to quantify the interactions between the carrier structure and drug release rate directly.The heat release rates in the heat-flow diagrams are basically consistent with the DOX release rate,thereby showing that microcalorimetry assay not only provides a unique thermodynamic explanation for the structure–activity relationship of Fe3O4@SiO2@NaYF4:Yb,Er MUCNRs but also provides powerful guidance to avoid the blind selection or design of drug carriers.Therefore,our work firmly provided a comprehensive perspective for using Fe3O4@SiO2@NaYF4:Yb,Er MUCNRs as a remarkable magnetic targeted drug carrier.