This study investigated the contents and distribution of collagen Ⅴ (Col Ⅴ) in skin lesions of the patients with systemic sclerosis (SSc) and its roles in the pathogenesis. The contents and distribution for α1 ...This study investigated the contents and distribution of collagen Ⅴ (Col Ⅴ) in skin lesions of the patients with systemic sclerosis (SSc) and its roles in the pathogenesis. The contents and distribution for α1 chain of collagen type Ⅰ, Ⅲ and V [α1 (Ⅰ), α1 (Ⅲ) and α1 (Ⅴ)] in skin lesions of 36 patients with SSc (9 cases of mild fibrosis, 14 moderate, and 13 severe) were detected by using im- munohistochemical SP method. Six cases of normal skin tissues served as controls. The results showed that there was diffuse distribution for three kinds of collagens in dermis. The deep staining α1 (Ⅰ) and α1 (Ⅲ) masses or bands were seen in reticular layer, while α1 (Ⅴ) was distributed more ho- mogeneously. From control to weak, moderate and severe fibrosis stages, α1 (Ⅰ), α1 (Ⅲ) and α1 (V) showed a gradually increased trend in skin lesions (P〈0.05). α1 (Ⅴ) was obviously elevated in skin lesions at early stage and persisted in whole fibrotic process and risen in greater contents, while α1 (Ⅰ) and α1 (Ⅲ) were to go higher late and were apparently elevated at moderate and late stages. Com- pared with α1 (Ⅰ), α1 (Ⅴ) took leading increase at early stage in skin lesions (P〈0.01), and had more elevated contents than α1 (Ⅲ) at moderate and late stages. The fibrotic changes in dermal reticular layer occurred earlier than those in papillary layer, and the abnormalities of α1 (Ⅴ)/α1 (I) ratio ap- peared before α1 (Ⅲ)/α1 (Ⅰ) ratio. It was concluded that a lot of α1 (Ⅴ) began to deposit in greater contents prior to α1 (Ⅰ) and α1 (Ⅲ) at early stage in SSc and persisted in whole fibrotic process. The changes of α1 (Ⅴ) contents in reticular layer occurred earlier than those in papillary layer, and it sug- gested that the fibrosis in reticular layer appeared earlier.展开更多
Soil organic carbon (SOC) and soil total nitrogen (STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosyst...Soil organic carbon (SOC) and soil total nitrogen (STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, pH, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0-40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.展开更多
In this paper we analytically and numerically consider the dynamical behavior of a certain predator-prey system with Holling type II functional response, including local and global stability analysis, existence of lim...In this paper we analytically and numerically consider the dynamical behavior of a certain predator-prey system with Holling type II functional response, including local and global stability analysis, existence of limit cycles, transcritical and Hopf bifurcations. Mathematical theory derivation mainly focuses on the existence and stability of equilibrium point as well as threshold conditions for transcritical and Hopf bifurcation, which can in turn provide a theoretical support for numerical simulation. Numerical analysis indicates that theoretical derivation results are correct and feasible. In addition, it is successful to show that the dynamical behavior of this predator-prey system mainly depends on some critical parameters and mathematical relationships. All these results are expected to be meaningful in the study of the dynamic complexity of predatory ecosystem.展开更多
In this paper, we mainly considered the dynamical behavior of a predator-prey system with Holling type II functional response and Allee-like effect on predator, including stability analysis of equilibria and Hopf bifu...In this paper, we mainly considered the dynamical behavior of a predator-prey system with Holling type II functional response and Allee-like effect on predator, including stability analysis of equilibria and Hopf bifurcation. Firstly, we gave some sufficient conditions to guarantee the existence, the local and global stability of equilibria as well as non-existence of limit cycles. By using the cobweb model, some cases about the existence of interior equilibrium are also illustrated with numerical outcomes. These existence and stability conclusions of interior equilibrium are also suitable in corresponding homogeneous reaction-diffusion system subject to the Neumann boundary conditions. Secondly, we theoretically deduced that our system has saddle-node bifurcation, transcritical bifurcation and Hopf bifurcation under certain conditions. Finally, for the Hopf bifurcation, we choose d as the bifurcation parameter and presented some numerical simulations to verify feasibility and effectiveness of the theoretical derivation corresponding to the existence of yk, respectively. The Hopf bifurcations are supercritical and limit cycles generated by the critical points are stable.展开更多
This paper studies the symmetry of Lagrangians of nonholonomic systems of non-Chetaev's type. First, the definition and the criterion of the symmetry of the system are given. Secondly, it obtains the condition under ...This paper studies the symmetry of Lagrangians of nonholonomic systems of non-Chetaev's type. First, the definition and the criterion of the symmetry of the system are given. Secondly, it obtains the condition under which there exists a conserved quantity and the form of the conserved quantity. Finally, an example is shown to illustrate the application of the result.展开更多
In this article, the authors investigate the existence problem for Hardy Henon type strongly indefinite elliptic systems. Existence results are obtained for such systems with superlinear subcritical nonlinearities.
In this paper Hopf bifurcation control is implemented in order to change the bifurcation from supercritical to subcritical in a differential equations system of Lorenz type. To achieve this purpose: first, a region of...In this paper Hopf bifurcation control is implemented in order to change the bifurcation from supercritical to subcritical in a differential equations system of Lorenz type. To achieve this purpose: first, a region of parameters is identified where the system has a supercritical Hopf bifurcation;second, a class of non-linear feedback control laws is proposed;finally, it is shown that there are control laws which the disturbed system undergoes subcritical Hopf bifurcation.展开更多
The discovery of new-type ore deposits, an important approach to guarantee the mineral resources supply in the 21st century, often brings about a gigantic increase in the mineral resources reserves. The analysis of mi...The discovery of new-type ore deposits, an important approach to guarantee the mineral resources supply in the 21st century, often brings about a gigantic increase in the mineral resources reserves. The analysis of mineralization system is of great importance to the discovery of new type ore deposits. ① The understanding of the relationship among various ore deposit types within a mineralization system in a region can help us to locate the unknown ore deposit types from the known ore deposit types, evidence that has been proved in the mineral prospecting history of ore belts in the middle and lower reaches of the Yangtze River, China. ② The understanding of the spatial structure of a mineralization system, especially of the vertical zonation, is helpful for the discovery of the concealed ore deposit types. ③ Clarifying the temporal structure of a mineralization system, including the iteration relationship between the mineral deposit types in the mineralization, leads to the location of the missing mineralization chains from the known mineralization chains (mineral deposit type), a method often proved to be effective in the magmatic hydrothermal mineralization system.④ Clarifying the factors restraining the diversity of mineral deposit types in mineralization system leads to the discovery of the potential of new type mineral deposits in relevant region. ⑤ Studying new mineralization setting and new ore forming processes leads to discovery of new type mineral deposit. More probabilities of discovery of new type mineral deposits are present in biogenic mineralization system, deep sea mineralization system, low temperature mineralization system, tectonic mineralization system and superimposed mineralization system.展开更多
The main purpose of this paper is to study the persistence of the general multispecies competition predator-pray system with Holling Ⅲ type functional response. In this system, the competition among predator species ...The main purpose of this paper is to study the persistence of the general multispecies competition predator-pray system with Holling Ⅲ type functional response. In this system, the competition among predator species and among prey species are simultaneously considered. By using the comparison theory and qualitative analysis, the sufficient conditions for uniform strong persistence are obtained.展开更多
Based on the practice of Baosteel' s 60000 m3/h air separation unit (ASU) ,which is the first domestically- integrated unit of such a scale, this paper studies the principles of type selection of the distribution c...Based on the practice of Baosteel' s 60000 m3/h air separation unit (ASU) ,which is the first domestically- integrated unit of such a scale, this paper studies the principles of type selection of the distribution control system (DCS). It discusses the design of the unit's control system,which involves a compressor system,a purification system (molecular sieving), a turbo expansion system and an air separation system. The final part of the paper discusses the maintenance and future development of the ASU control system at Baosteel.展开更多
We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion...We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.展开更多
The transient stability of a single machine to infinite-busbar power system with resistortype superconducting fault current limiters (SFCL) is analyzed under asymmetrical short-circuit fault conditions. The SFCL is ...The transient stability of a single machine to infinite-busbar power system with resistortype superconducting fault current limiters (SFCL) is analyzed under asymmetrical short-circuit fault conditions. The SFCL is considered to introduce a resistance into the three-phase circuits when faults occur. Based on the power-angle curves for different short-circuit conditions of the single-line to ground, double-line to ground and line to line short-circuit faults, the influences of the SFCLs on transient stability are analyzed in detail. The time-domain simulation of transient stability is carried out to verify the analytical results.展开更多
The modem term 'agroforestry system' is derived from agricultural practices. It is an organic combination of agriculture and forestry, ecology and economy, product variation and scientific management. On the b...The modem term 'agroforestry system' is derived from agricultural practices. It is an organic combination of agriculture and forestry, ecology and economy, product variation and scientific management. On the basis of analyzing the types and structure of agroforestry system in the Three Gorges Reservoir area,the paper poins out that agroforestry system can be divided into diffend structutal levds. Taking some typical cases as examples, it compares the benefits of four kinds of structures. The result illustrates that the hedge row agroforestry system on slopeland is an effective way to realize coordinate development of ecology and economy.展开更多
The time dependent vehicle routing problem with time windows(TDVRPTW) is considered. A multi-type ant system(MTAS) algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS) algorithm...The time dependent vehicle routing problem with time windows(TDVRPTW) is considered. A multi-type ant system(MTAS) algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS) algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection(NNS) mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW) benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.展开更多
In this paper, we are concerned with the following Hardy-Sobolev type system{(-?)^(α/2) u(x) =v^q(x)/|y|^(t_2) (-?)α/2 v(x) =u^p(x)/|y|^(t_1),x =(y, z) ∈(R ~k\{0}) × R^(n-k),(0.1)where 0 < α < n, 0 <...In this paper, we are concerned with the following Hardy-Sobolev type system{(-?)^(α/2) u(x) =v^q(x)/|y|^(t_2) (-?)α/2 v(x) =u^p(x)/|y|^(t_1),x =(y, z) ∈(R ~k\{0}) × R^(n-k),(0.1)where 0 < α < n, 0 < t_1, t_2 < min{α, k}, and 1 < p ≤ τ_1 :=(n+α-2t_1)/( n-α), 1 < q ≤ τ_2 :=(n+α-2 t_2)/( n-α).We first establish the equivalence of classical and weak solutions between PDE system(0.1)and the following integral equations(IE) system{u(x) =∫_( R^n) G_α(x, ξ)v^q(ξ)/|η|t^2 dξ v(x) =∫_(R^n) G_α(x, ξ)(u^p(ξ))/|η|^(t_1) dξ,(0.2)where Gα(x, ξ) =(c n,α)/(|x-ξ|^(n-α))is the Green's function of(-?)^(α/2) in R^n. Then, by the method of moving planes in the integral forms, in the critical case p = τ_1 and q = τ_2, we prove that each pair of nonnegative solutions(u, v) of(0.1) is radially symmetric and monotone decreasing about the origin in R^k and some point z0 in R^(n-k). In the subcritical case (n-t_1)/(p+1)+(n-t_2)/(q+1)> n-α,1 < p ≤ τ_1 and 1 < q ≤ τ_2, we derive the nonexistence of nontrivial nonnegative solutions for(0.1).展开更多
In this paper, we study the persistence of lower dimensional tori for random Hamiltonian systems, which shows that majority of the unperturbed tori persist as Cantor fragments of lower dimensional ones under small per...In this paper, we study the persistence of lower dimensional tori for random Hamiltonian systems, which shows that majority of the unperturbed tori persist as Cantor fragments of lower dimensional ones under small perturbation. Using this result, we can describe the stability of the non-autonomous dynamic systems.展开更多
The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave a...The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation (RWA). It is shown that population transfer is mainly determined by the Rabi frequency (strength) of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.展开更多
Fault management study in smart grid systems (SGSs) is important to ensure the stability of the system. Also, it is important to know the major types of power failures for the effective operation of the SGS. This pape...Fault management study in smart grid systems (SGSs) is important to ensure the stability of the system. Also, it is important to know the major types of power failures for the effective operation of the SGS. This paper reviews diverse types of faults that might appear in the SGS and gives a survey about the impact of renewable energy resources (RERs) on the behavior of the system. Moreover, this paper offers different fault detection and localization techniques that can be used for SGSs. Furthermore, a potential fault management case study is proposed in this paper. The SGS model in this paper is investigated using both of the Matlab/Simulink and the Real Time Digital Simulation (RTDS) to compute the fault management study. Simulation results show the fast response to a power failure in the system which improves the stability of the SGS.展开更多
In this paper, a necessary and sufficient condition for teh solution of Lienard typesystem with muliiple singular points to oscillation under the more general assumptionis given.Results of the papers [1-4] are also ex...In this paper, a necessary and sufficient condition for teh solution of Lienard typesystem with muliiple singular points to oscillation under the more general assumptionis given.Results of the papers [1-4] are also extended and improved in this paper.展开更多
In this study, Va 1686 gene was cloned from Vibrio alginolyticus . The total length of the gene is 1 164 bp, and it could encode 387 amino acids. The physicochemical properties, protein structure, genetic evolutionary...In this study, Va 1686 gene was cloned from Vibrio alginolyticus . The total length of the gene is 1 164 bp, and it could encode 387 amino acids. The physicochemical properties, protein structure, genetic evolutionary relationship and antigenic characteristics of the effect protein Va1686 of V. alginolyticus HY9901 type Ⅲ secretion system were studied and analyzed by bioinformatics methods and tools. The results showed that Va1686 is a stable hydrophilic and acidic protein without a transmembrane region and a signal peptide, and secondary structure to α-helix. The evolutionary analysis showed that V. alginolyticus HY9901 and V. harveyi were clustered together, which indicated that the genetic relationship between the two species was the closest. Va1686 contains a Fic superfamily conserved domain associated with cell division. Bioinformatics analysis showed that the B-cell preponderant epitopes of Va1686 might be localized in the regions of 48-49, 82-85, 125-126, 150-153, 185-186, 236-237 and so on. The 3D structure model of Va1686 subunit was simulated by SWISS-MODEL software and it was found that the vopS of V. parahaemolyticus was similar and the similarity was 89.46%. In this study, the feasibility of Va1686 as a common antigen of Vibrio was verified from the perspective of bioinformatics, which laid the foundation for the next step in vaccine development.展开更多
文摘This study investigated the contents and distribution of collagen Ⅴ (Col Ⅴ) in skin lesions of the patients with systemic sclerosis (SSc) and its roles in the pathogenesis. The contents and distribution for α1 chain of collagen type Ⅰ, Ⅲ and V [α1 (Ⅰ), α1 (Ⅲ) and α1 (Ⅴ)] in skin lesions of 36 patients with SSc (9 cases of mild fibrosis, 14 moderate, and 13 severe) were detected by using im- munohistochemical SP method. Six cases of normal skin tissues served as controls. The results showed that there was diffuse distribution for three kinds of collagens in dermis. The deep staining α1 (Ⅰ) and α1 (Ⅲ) masses or bands were seen in reticular layer, while α1 (Ⅴ) was distributed more ho- mogeneously. From control to weak, moderate and severe fibrosis stages, α1 (Ⅰ), α1 (Ⅲ) and α1 (V) showed a gradually increased trend in skin lesions (P〈0.05). α1 (Ⅴ) was obviously elevated in skin lesions at early stage and persisted in whole fibrotic process and risen in greater contents, while α1 (Ⅰ) and α1 (Ⅲ) were to go higher late and were apparently elevated at moderate and late stages. Com- pared with α1 (Ⅰ), α1 (Ⅴ) took leading increase at early stage in skin lesions (P〈0.01), and had more elevated contents than α1 (Ⅲ) at moderate and late stages. The fibrotic changes in dermal reticular layer occurred earlier than those in papillary layer, and the abnormalities of α1 (Ⅴ)/α1 (I) ratio ap- peared before α1 (Ⅲ)/α1 (Ⅰ) ratio. It was concluded that a lot of α1 (Ⅴ) began to deposit in greater contents prior to α1 (Ⅰ) and α1 (Ⅲ) at early stage in SSc and persisted in whole fibrotic process. The changes of α1 (Ⅴ) contents in reticular layer occurred earlier than those in papillary layer, and it sug- gested that the fibrosis in reticular layer appeared earlier.
基金supported by the National Science and Technology Support Program of China (2014BAC15B04)
文摘Soil organic carbon (SOC) and soil total nitrogen (STN) in arid regions are important components of global C and the N cycles, and their response to climate change will have important implications for both ecosystem processes and global climate feedbacks. Grassland ecosystems of Funyun County in the southern foot of the Altay Mountains are characterized by complex topography, suggesting large variability in the spatial distribution of SOC and STN. However, there has been little investigation of SOC and STN on grasslands in arid regions with a mountain-basin structure. Therefore, we investigated the characteristics of SOC and STN in different grassland types in a mountain-basin system at the southern foot of the Altai Mountains, north of the Junggar Basin in China, and explored their potential influencing factors and relationships with meteorological factors and soil properties. We found that the concentrations and storages of SOC and STN varied significantly with grassland type, and showed a decreasing trend along a decreasing elevation gradient in alpine meadow, mountain meadow, temperate typical steppe, temperate steppe desert, and temperate steppe desert. In addition, the SOC and STN concentrations decreased with depth, except in the temperate desert steppe. According to Pearson's correlation values and redundancy analysis, the mean annual precipitation, soil moisture content and soil available N concentration were significantly positively correlated with the SOC and STN concentrations. In contrast, the mean annual temperature, pH, and soil bulk density were significantly and negatively correlated with the SOC and STN concentrations. The mean annual precipitation and mean annual temperature were the primary factors related to the SOC and STN concentrations. The distributions of the SOC and STN concentrations were highly regulated by the elevation-induced differences in meteorological factors. Mean annual precipitation and mean annual temperature together explained 97.85% and 98.38% of the overall variations in the SOC and STN concentrations, respectively, at soil depth of 0-40 cm, with precipitation making the greatest contribution. Our results provide a basis for estimating and predicting SOC and STN concentrations in grasslands in arid regions with a mountain-basin structure.
文摘In this paper we analytically and numerically consider the dynamical behavior of a certain predator-prey system with Holling type II functional response, including local and global stability analysis, existence of limit cycles, transcritical and Hopf bifurcations. Mathematical theory derivation mainly focuses on the existence and stability of equilibrium point as well as threshold conditions for transcritical and Hopf bifurcation, which can in turn provide a theoretical support for numerical simulation. Numerical analysis indicates that theoretical derivation results are correct and feasible. In addition, it is successful to show that the dynamical behavior of this predator-prey system mainly depends on some critical parameters and mathematical relationships. All these results are expected to be meaningful in the study of the dynamic complexity of predatory ecosystem.
文摘In this paper, we mainly considered the dynamical behavior of a predator-prey system with Holling type II functional response and Allee-like effect on predator, including stability analysis of equilibria and Hopf bifurcation. Firstly, we gave some sufficient conditions to guarantee the existence, the local and global stability of equilibria as well as non-existence of limit cycles. By using the cobweb model, some cases about the existence of interior equilibrium are also illustrated with numerical outcomes. These existence and stability conclusions of interior equilibrium are also suitable in corresponding homogeneous reaction-diffusion system subject to the Neumann boundary conditions. Secondly, we theoretically deduced that our system has saddle-node bifurcation, transcritical bifurcation and Hopf bifurcation under certain conditions. Finally, for the Hopf bifurcation, we choose d as the bifurcation parameter and presented some numerical simulations to verify feasibility and effectiveness of the theoretical derivation corresponding to the existence of yk, respectively. The Hopf bifurcations are supercritical and limit cycles generated by the critical points are stable.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10932002 and 10772025)the Fund for Fundamental Research of Beijing Institute of Technology
文摘This paper studies the symmetry of Lagrangians of nonholonomic systems of non-Chetaev's type. First, the definition and the criterion of the symmetry of the system are given. Secondly, it obtains the condition under which there exists a conserved quantity and the form of the conserved quantity. Finally, an example is shown to illustrate the application of the result.
文摘In this article, the authors investigate the existence problem for Hardy Henon type strongly indefinite elliptic systems. Existence results are obtained for such systems with superlinear subcritical nonlinearities.
文摘In this paper Hopf bifurcation control is implemented in order to change the bifurcation from supercritical to subcritical in a differential equations system of Lorenz type. To achieve this purpose: first, a region of parameters is identified where the system has a supercritical Hopf bifurcation;second, a class of non-linear feedback control laws is proposed;finally, it is shown that there are control laws which the disturbed system undergoes subcritical Hopf bifurcation.
文摘The discovery of new-type ore deposits, an important approach to guarantee the mineral resources supply in the 21st century, often brings about a gigantic increase in the mineral resources reserves. The analysis of mineralization system is of great importance to the discovery of new type ore deposits. ① The understanding of the relationship among various ore deposit types within a mineralization system in a region can help us to locate the unknown ore deposit types from the known ore deposit types, evidence that has been proved in the mineral prospecting history of ore belts in the middle and lower reaches of the Yangtze River, China. ② The understanding of the spatial structure of a mineralization system, especially of the vertical zonation, is helpful for the discovery of the concealed ore deposit types. ③ Clarifying the temporal structure of a mineralization system, including the iteration relationship between the mineral deposit types in the mineralization, leads to the location of the missing mineralization chains from the known mineralization chains (mineral deposit type), a method often proved to be effective in the magmatic hydrothermal mineralization system.④ Clarifying the factors restraining the diversity of mineral deposit types in mineralization system leads to the discovery of the potential of new type mineral deposits in relevant region. ⑤ Studying new mineralization setting and new ore forming processes leads to discovery of new type mineral deposit. More probabilities of discovery of new type mineral deposits are present in biogenic mineralization system, deep sea mineralization system, low temperature mineralization system, tectonic mineralization system and superimposed mineralization system.
基金Supported by the National Natural Science Foundation of China (10701020)
文摘The main purpose of this paper is to study the persistence of the general multispecies competition predator-pray system with Holling Ⅲ type functional response. In this system, the competition among predator species and among prey species are simultaneously considered. By using the comparison theory and qualitative analysis, the sufficient conditions for uniform strong persistence are obtained.
文摘Based on the practice of Baosteel' s 60000 m3/h air separation unit (ASU) ,which is the first domestically- integrated unit of such a scale, this paper studies the principles of type selection of the distribution control system (DCS). It discusses the design of the unit's control system,which involves a compressor system,a purification system (molecular sieving), a turbo expansion system and an air separation system. The final part of the paper discusses the maintenance and future development of the ASU control system at Baosteel.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60978013)the Shanghai Rising Star Project,China (Grant No. 11QA1407400)
文摘We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.
文摘The transient stability of a single machine to infinite-busbar power system with resistortype superconducting fault current limiters (SFCL) is analyzed under asymmetrical short-circuit fault conditions. The SFCL is considered to introduce a resistance into the three-phase circuits when faults occur. Based on the power-angle curves for different short-circuit conditions of the single-line to ground, double-line to ground and line to line short-circuit faults, the influences of the SFCLs on transient stability are analyzed in detail. The time-domain simulation of transient stability is carried out to verify the analytical results.
文摘The modem term 'agroforestry system' is derived from agricultural practices. It is an organic combination of agriculture and forestry, ecology and economy, product variation and scientific management. On the basis of analyzing the types and structure of agroforestry system in the Three Gorges Reservoir area,the paper poins out that agroforestry system can be divided into diffend structutal levds. Taking some typical cases as examples, it compares the benefits of four kinds of structures. The result illustrates that the hedge row agroforestry system on slopeland is an effective way to realize coordinate development of ecology and economy.
文摘The time dependent vehicle routing problem with time windows(TDVRPTW) is considered. A multi-type ant system(MTAS) algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS) algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection(NNS) mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW) benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.
基金supported by the NNSF of China(11371056)partly supported by the NNSF of China(11501021)+1 种基金the China Postdoctoral Science Foundation(2013M540057)partly supported by Scientific Research Fund of Jiangxi Provincial Education Department(GJJ160797)
文摘In this paper, we are concerned with the following Hardy-Sobolev type system{(-?)^(α/2) u(x) =v^q(x)/|y|^(t_2) (-?)α/2 v(x) =u^p(x)/|y|^(t_1),x =(y, z) ∈(R ~k\{0}) × R^(n-k),(0.1)where 0 < α < n, 0 < t_1, t_2 < min{α, k}, and 1 < p ≤ τ_1 :=(n+α-2t_1)/( n-α), 1 < q ≤ τ_2 :=(n+α-2 t_2)/( n-α).We first establish the equivalence of classical and weak solutions between PDE system(0.1)and the following integral equations(IE) system{u(x) =∫_( R^n) G_α(x, ξ)v^q(ξ)/|η|t^2 dξ v(x) =∫_(R^n) G_α(x, ξ)(u^p(ξ))/|η|^(t_1) dξ,(0.2)where Gα(x, ξ) =(c n,α)/(|x-ξ|^(n-α))is the Green's function of(-?)^(α/2) in R^n. Then, by the method of moving planes in the integral forms, in the critical case p = τ_1 and q = τ_2, we prove that each pair of nonnegative solutions(u, v) of(0.1) is radially symmetric and monotone decreasing about the origin in R^k and some point z0 in R^(n-k). In the subcritical case (n-t_1)/(p+1)+(n-t_2)/(q+1)> n-α,1 < p ≤ τ_1 and 1 < q ≤ τ_2, we derive the nonexistence of nontrivial nonnegative solutions for(0.1).
基金Partially supported by the SFC(10531050,10225107)of Chinathe SRFDP(20040183030)the 985 program of Jilin University
文摘In this paper, we study the persistence of lower dimensional tori for random Hamiltonian systems, which shows that majority of the unperturbed tori persist as Cantor fragments of lower dimensional ones under small perturbation. Using this result, we can describe the stability of the non-autonomous dynamic systems.
基金supported by National Basic Research Program of China (Grant No 2006CB806003)the Natural Science Foundation of Shandong Province,China (Grant No Y2006A21)+1 种基金the National Natural Science Foundation of China (Grant No 10675076)State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,China
文摘The population transfer in a ladder-type atomic system driven by linearly polarized sech-shape femtosecond laser pulses is investigated by numerically solving Schr6dinger equation without including the rotating wave approximation (RWA). It is shown that population transfer is mainly determined by the Rabi frequency (strength) of the driving laser field and the chirp rate, and that the ratio of the dipole moments and the pulse width also have a prominent effect on the population transfer. By choosing appropriate values of the above parameters, complete population transfer can be realized.
文摘Fault management study in smart grid systems (SGSs) is important to ensure the stability of the system. Also, it is important to know the major types of power failures for the effective operation of the SGS. This paper reviews diverse types of faults that might appear in the SGS and gives a survey about the impact of renewable energy resources (RERs) on the behavior of the system. Moreover, this paper offers different fault detection and localization techniques that can be used for SGSs. Furthermore, a potential fault management case study is proposed in this paper. The SGS model in this paper is investigated using both of the Matlab/Simulink and the Real Time Digital Simulation (RTDS) to compute the fault management study. Simulation results show the fast response to a power failure in the system which improves the stability of the SGS.
文摘In this paper, a necessary and sufficient condition for teh solution of Lienard typesystem with muliiple singular points to oscillation under the more general assumptionis given.Results of the papers [1-4] are also extended and improved in this paper.
基金Supported by Shenzhen Science and Technology Project(JCYJ20170818111629778,JCYJ20170306161613251)National Natural Science Foundation of Guangdong Province(2017A030313174)+2 种基金Natural Science Foundation of Guangdong Ocean University(C17379)Undergraduate Innovative and Entrepreneurial Team Project(CCTD201802)Science and Technology Program of Guangdong Province(2015A020209163)
文摘In this study, Va 1686 gene was cloned from Vibrio alginolyticus . The total length of the gene is 1 164 bp, and it could encode 387 amino acids. The physicochemical properties, protein structure, genetic evolutionary relationship and antigenic characteristics of the effect protein Va1686 of V. alginolyticus HY9901 type Ⅲ secretion system were studied and analyzed by bioinformatics methods and tools. The results showed that Va1686 is a stable hydrophilic and acidic protein without a transmembrane region and a signal peptide, and secondary structure to α-helix. The evolutionary analysis showed that V. alginolyticus HY9901 and V. harveyi were clustered together, which indicated that the genetic relationship between the two species was the closest. Va1686 contains a Fic superfamily conserved domain associated with cell division. Bioinformatics analysis showed that the B-cell preponderant epitopes of Va1686 might be localized in the regions of 48-49, 82-85, 125-126, 150-153, 185-186, 236-237 and so on. The 3D structure model of Va1686 subunit was simulated by SWISS-MODEL software and it was found that the vopS of V. parahaemolyticus was similar and the similarity was 89.46%. In this study, the feasibility of Va1686 as a common antigen of Vibrio was verified from the perspective of bioinformatics, which laid the foundation for the next step in vaccine development.