The influence of hot working on the microstructures of TC11/Ti2 Al Nb dual-alloy joints welded by electron beam welding(EBW) process was investigated. The tensile tests were performed at room temperature for specimens...The influence of hot working on the microstructures of TC11/Ti2 Al Nb dual-alloy joints welded by electron beam welding(EBW) process was investigated. The tensile tests were performed at room temperature for specimens before and after thermal exposure. The results show that the fusion zone of TC11/Ti2 Al Nb dual-alloy joint welded by EBW is mainly composed of β phase. After deformation and heat treatment, the grain boundaries of the as-cast alloy are broken and the fusion zone mainly consists of β, α2and α phases. The fusion zone performs poor property in the tensile test. Specimens before and after thermal exposure all fail in this area under different deformation conditions. The ultimate tensile strength of specimens after heat treatment is up to 1190 MPa at room temperature. The joints by water quenching after deformation have better plasticity with an elongation up to 4.4%. After thermal exposure at 500 °C for 100 h, the tensile strength of the specimen slightly rises while the ductility changes a little. SEM observation shows that the fracture mechanism is predominantly transgranular under different deformation conditions.展开更多
[Objective] The aim of this study was to elucidate the quantitative traits of plants mutagenized by ion beam. [Method] The particular variation phenotypes, a- gronomic traits, and protein and wet gluten contents of pr...[Objective] The aim of this study was to elucidate the quantitative traits of plants mutagenized by ion beam. [Method] The particular variation phenotypes, a- gronomic traits, and protein and wet gluten contents of progenies derived from the same ion beam induced mutant were investigated. [Result] Morphological polymor- phism existed in some individuals. Plant height, spike length and protein content were significantly influenced by ion beam, and effective tiller number and wet gluten content were moderately influenced. Multiple comparisons of all the indices within groups indicated genomic instability among these groups. Coefficient of variation im- plied the differences within group were very low. [Conclusion] Ion beam irradiation displayed characteristics of multi-directivity and non-directiveness. It aroused multiple variations in the same mutant. Instability among progeny indicates cells had different fate even in the same irradiated tissue. It may take several generations for mutants to stabilize particular phenotypes. The effects of ion beam irradiation may be the in- terrelated direct irradiation damage, indirect irradiation damage and late effect, such as bystander effect and adaptive response.展开更多
A two-stage multi-objective optimization model-predictive control algorithms(MPC) strategy is presented. A domain MPC controller with input constraints is used to increase freedom for steady-state objective and enhanc...A two-stage multi-objective optimization model-predictive control algorithms(MPC) strategy is presented. A domain MPC controller with input constraints is used to increase freedom for steady-state objective and enhance stabilization of the controller. A steady-state objective optimization algorithm oriented to transient process is adopted to realize optimization of objectives else than dynamic control. It is proved that the stabilization for both dynamic control and steady-state objective optimization can be guaranteed. The theoretical results are demonstrated and discussed using a distillation tower as the model. Theoretical analysis and simulation results show that this control strategy is efficient and provides a good strategic solution to practical process control.展开更多
For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state ...For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state observer for the controlled system, the sufficient condition to convergence of the state error was derived. Under a simple assumption on the initial state error, we presented an LMI-based method to design the constrained feedback gain and the observer gain. An example was used to illustrate our results.展开更多
The boundary stabilization problem of a Timoshenko beam attached with a mass at one end is studied. First, with linear boundary force feedback and moment control simultaneously at the end attached with the load, the e...The boundary stabilization problem of a Timoshenko beam attached with a mass at one end is studied. First, with linear boundary force feedback and moment control simultaneously at the end attached with the load, the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t →∞. Then, some counterexamples are given to show that, in other casest the corresponding closed loop system is, in general, not stable asymtotically, let alone exponentially.展开更多
In this paper, we introduce a multi-material arbitrary Lagrangian and Eulerian method for the hydrodynamic radiative multi-group diffusion model in 2D cylindrical coordinates. The basic idea in the construction of the...In this paper, we introduce a multi-material arbitrary Lagrangian and Eulerian method for the hydrodynamic radiative multi-group diffusion model in 2D cylindrical coordinates. The basic idea in the construction of the method is the following： In the Lagrangian step, a closure model of radiation-hydrodynamics is used to give the states of equations for materials in mixed cells. In the mesh rezoning step, we couple the rezoning principle with the Lagrangian interface tracking method and an Eulerian interface capturing scheme to compute interfaces sharply according to their deformation and to keep cells in good geometric quality. In the interface reconstruction step, a dual-material Moment-of-Fluid method is introduced to obtain the unique interface in mixed ceils. In the remapping step, a conservative remapping algorithm of conserved quantities is presented. A munber of numerical tests are carried out and the numerical results show that the new method can simulate instabilities in complex fluid field under large deformation, and are accurate and robust.展开更多
Intrinsically disordered proteins （IDPs）/intrinsicaUy unstructured proteins are characterized by the lack of fixed or stable tertiary structure, and are increasingly recognized as an important class of proteins with...Intrinsically disordered proteins （IDPs）/intrinsicaUy unstructured proteins are characterized by the lack of fixed or stable tertiary structure, and are increasingly recognized as an important class of proteins with major roles in signal transduction and transcriptional regulation. In this study, we report the identification and functional characterization of a previously uncharacterized protein （UPFO258/KIAA1024）, major intrinsically disordered Notch2-associated receptor 1 （MINAR1）. While MINAR1 carries a single transmembrane domain and a short cytoplasmic domain, it has a large extraceUular domain that shares no similarity with known protein sequences. Uncharacteristically, MINAR1 is a highly IDP with nearly 70% of its amino acids sequences unstructured. We demonstrate that MINAR1 physically interacts with Notch2 and its binding to Notch2 increases its stability and function. MINAR1 is widely expressed in various tissues including the epithelial cells of the breast and endothelial cells of blood vessels. MINAR1 plays a negative role in angioganesis as it inhibits angioganesis in cell culture and in mouse matrigal plug and zebraflsh anglo- genesis models. Furthermore, while MINAR1 is highly expressed in the normal human breast, its expression is significantly down- regulated in advanced human breast cancer and its re-expression in breast cancer cells inhibited tumor growth. Our study demonstrates that MINAR1 is an IDP that negatively regulates angioganesis and growth of breast cancer cells.展开更多
The stabilization problem of a nonuniform Timoshenko beam system with controllers at the beam's right tip with rotor inertia is studied.First,with a special kind of linear boundary force feedback and moment contro...The stabilization problem of a nonuniform Timoshenko beam system with controllers at the beam's right tip with rotor inertia is studied.First,with a special kind of linear boundary force feedback and moment control existing simultaneously,the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t→∞.Then in other cases,some conditions for the corresponding closed loop system to be asymptotically stable are also derived.展开更多
Inertial fusion energy （IFE） has been considered a promising, nearly inexhaustible source of sustainable carbon-free power for the world＇s energy future. It has long been recognized that the control of hydrodynamic...Inertial fusion energy （IFE） has been considered a promising, nearly inexhaustible source of sustainable carbon-free power for the world＇s energy future. It has long been recognized that the control of hydrodynamic instabilities is of critical importance for ignition and high-gain in the inertial-confinement fusion （ICF） hot-spot ignition scheme. In this mini-review, we summarize the progress of theoretical and simulation research of hydrodynamic instabilities in the ICF central hot-spot implosion in our group over the past decade. In order to obtain sufficient understanding of the growth of hydrodynamic instabilities in ICF, we first decompose the problem into different stages according to the implosion physics processes. The decomposed essential physics pro- cesses that are associated with ICF implosions, such as Rayleigh-Taylor instability （RTI）, Richtmyer-Meshkov instability （RMI）, Kelvin-Helmholtz instability （KHI）, convergent geometry effects, as well as perturbation feed-through are reviewed. Analyti- cal models in planar, cylindrical, and spherical geometries have been established to study different physical aspects, including density-gradient, interface-coupling, geometry, and convergent effects. The influence of ablation in the presence of preheating on the RTI has been extensively studied by numerical simulations. The KHI considering the ablation effect has been discussed in detail for the first time. A series of single-mode ablative RTI experiments has been performed on the Shenguang-II laser facility. The theoretical and simulation research provides us the physical insights of linear and weakly nonlinear growths, and nonlinear evolutions of the hydrodynamic instabilities in ICF implosions, which has directly supported the research of ICF ignition target design. The ICF hot-spot ignition implosion design that uses several controlling features, based on our current understanding of hydrodynamic instabilities, to address shell implosion stability, has been briefly described, several of which are novel.展开更多
Due to high data rates and reliability,inter-satellite laser communication has developed rapidly in these days.However,the stability of the laser beam pointing is still a key technique which needs to be solved;otherwi...Due to high data rates and reliability,inter-satellite laser communication has developed rapidly in these days.However,the stability of the laser beam pointing is still a key technique which needs to be solved;otherwise,the beam pointing jitter noise would reduce the communication quality or,even worse,would make the inter-satellite laser communication impossible.For this purpose,a bench-top of the fine beam pointing control system has been built and tested for inter-satellite laser communication.The pointing offset of more than 100rad is produced by the steering mirror.With beam pointing control system turned on,the offset could be rapidly suppressed to lower than 100 nrad in less than 0.5 s.Moreover,the pointing stability can be kept at 40 nrad for yaw motion and 62 nrad for pitch motion,when the received beam jitter is set at 20rad.展开更多
In this paper,the improved canonical quantization method of the self dual field is given in order to overcome linear combination problem about the second class constraint and the first class constraint number maximiza...In this paper,the improved canonical quantization method of the self dual field is given in order to overcome linear combination problem about the second class constraint and the first class constraint number maximization problem in the Dirac method.In the improved canonical quantization method,there are no artificial linear combination and the first class constraint number maximization problems,at the same time,the stability of the system is considered.Therefore,the improved canonical quantization method is more natural and easier accepted by people than the usual Dirac method.We use the improved canonical quantization method to realize the canonical quantization of the self dual field,which has relation with string theory successfully and the results are equal to the results by using the Dirac method.展开更多
基金Project(51175431)supported by the National Natural Science Foundation of China
文摘The influence of hot working on the microstructures of TC11/Ti2 Al Nb dual-alloy joints welded by electron beam welding(EBW) process was investigated. The tensile tests were performed at room temperature for specimens before and after thermal exposure. The results show that the fusion zone of TC11/Ti2 Al Nb dual-alloy joint welded by EBW is mainly composed of β phase. After deformation and heat treatment, the grain boundaries of the as-cast alloy are broken and the fusion zone mainly consists of β, α2and α phases. The fusion zone performs poor property in the tensile test. Specimens before and after thermal exposure all fail in this area under different deformation conditions. The ultimate tensile strength of specimens after heat treatment is up to 1190 MPa at room temperature. The joints by water quenching after deformation have better plasticity with an elongation up to 4.4%. After thermal exposure at 500 °C for 100 h, the tensile strength of the specimen slightly rises while the ductility changes a little. SEM observation shows that the fracture mechanism is predominantly transgranular under different deformation conditions.
基金Supported by National Natural Science Foundation of China (30800204)Basic and Frontier Technology Research Program of Henan Province (102300413206)~~
文摘[Objective] The aim of this study was to elucidate the quantitative traits of plants mutagenized by ion beam. [Method] The particular variation phenotypes, a- gronomic traits, and protein and wet gluten contents of progenies derived from the same ion beam induced mutant were investigated. [Result] Morphological polymor- phism existed in some individuals. Plant height, spike length and protein content were significantly influenced by ion beam, and effective tiller number and wet gluten content were moderately influenced. Multiple comparisons of all the indices within groups indicated genomic instability among these groups. Coefficient of variation im- plied the differences within group were very low. [Conclusion] Ion beam irradiation displayed characteristics of multi-directivity and non-directiveness. It aroused multiple variations in the same mutant. Instability among progeny indicates cells had different fate even in the same irradiated tissue. It may take several generations for mutants to stabilize particular phenotypes. The effects of ion beam irradiation may be the in- terrelated direct irradiation damage, indirect irradiation damage and late effect, such as bystander effect and adaptive response.
基金Supported by the National Natrural Science Foundation of China(No.69635010).
文摘A two-stage multi-objective optimization model-predictive control algorithms(MPC) strategy is presented. A domain MPC controller with input constraints is used to increase freedom for steady-state objective and enhance stabilization of the controller. A steady-state objective optimization algorithm oriented to transient process is adopted to realize optimization of objectives else than dynamic control. It is proved that the stabilization for both dynamic control and steady-state objective optimization can be guaranteed. The theoretical results are demonstrated and discussed using a distillation tower as the model. Theoretical analysis and simulation results show that this control strategy is efficient and provides a good strategic solution to practical process control.
文摘For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state observer for the controlled system, the sufficient condition to convergence of the state error was derived. Under a simple assumption on the initial state error, we presented an LMI-based method to design the constrained feedback gain and the observer gain. An example was used to illustrate our results.
基金Project supported by the the National Key Project of China.
文摘The boundary stabilization problem of a Timoshenko beam attached with a mass at one end is studied. First, with linear boundary force feedback and moment control simultaneously at the end attached with the load, the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t →∞. Then, some counterexamples are given to show that, in other casest the corresponding closed loop system is, in general, not stable asymtotically, let alone exponentially.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11371065, 11126134, 11401033, 91130002 and 91330205)the China Academy of Engineering Physics Project (Grant Nos.2012A0202010 and 2015B0202035)+2 种基金the National High Technology Research and Development Program of China (Grant No. 2012AA01A303)the Foundation of Science and Technology Computation Physics Laboratorythe National Hi-Tech Inertial Confinement Fusion Committee of China
文摘In this paper, we introduce a multi-material arbitrary Lagrangian and Eulerian method for the hydrodynamic radiative multi-group diffusion model in 2D cylindrical coordinates. The basic idea in the construction of the method is the following： In the Lagrangian step, a closure model of radiation-hydrodynamics is used to give the states of equations for materials in mixed cells. In the mesh rezoning step, we couple the rezoning principle with the Lagrangian interface tracking method and an Eulerian interface capturing scheme to compute interfaces sharply according to their deformation and to keep cells in good geometric quality. In the interface reconstruction step, a dual-material Moment-of-Fluid method is introduced to obtain the unique interface in mixed ceils. In the remapping step, a conservative remapping algorithm of conserved quantities is presented. A munber of numerical tests are carried out and the numerical results show that the new method can simulate instabilities in complex fluid field under large deformation, and are accurate and robust.
文摘Intrinsically disordered proteins （IDPs）/intrinsicaUy unstructured proteins are characterized by the lack of fixed or stable tertiary structure, and are increasingly recognized as an important class of proteins with major roles in signal transduction and transcriptional regulation. In this study, we report the identification and functional characterization of a previously uncharacterized protein （UPFO258/KIAA1024）, major intrinsically disordered Notch2-associated receptor 1 （MINAR1）. While MINAR1 carries a single transmembrane domain and a short cytoplasmic domain, it has a large extraceUular domain that shares no similarity with known protein sequences. Uncharacteristically, MINAR1 is a highly IDP with nearly 70% of its amino acids sequences unstructured. We demonstrate that MINAR1 physically interacts with Notch2 and its binding to Notch2 increases its stability and function. MINAR1 is widely expressed in various tissues including the epithelial cells of the breast and endothelial cells of blood vessels. MINAR1 plays a negative role in angioganesis as it inhibits angioganesis in cell culture and in mouse matrigal plug and zebraflsh anglo- genesis models. Furthermore, while MINAR1 is highly expressed in the normal human breast, its expression is significantly down- regulated in advanced human breast cancer and its re-expression in breast cancer cells inhibited tumor growth. Our study demonstrates that MINAR1 is an IDP that negatively regulates angioganesis and growth of breast cancer cells.
基金This research is supported by the National Natural Science Foundation of China (00174008).
文摘The stabilization problem of a nonuniform Timoshenko beam system with controllers at the beam's right tip with rotor inertia is studied.First,with a special kind of linear boundary force feedback and moment control existing simultaneously,the energy corresponding to the closed loop system is proven to be exponentially convergent to zero as time t→∞.Then in other cases,some conditions for the corresponding closed loop system to be asymptotically stable are also derived.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275031,11675026,11475032,11475034,11575033,and 11274026)the Foundation of President of Chinese Academy of Engineering Physics(Grant No.2014-1-040)the National Basic Research Program of China(Grant No.2013CB834100)
文摘Inertial fusion energy （IFE） has been considered a promising, nearly inexhaustible source of sustainable carbon-free power for the world＇s energy future. It has long been recognized that the control of hydrodynamic instabilities is of critical importance for ignition and high-gain in the inertial-confinement fusion （ICF） hot-spot ignition scheme. In this mini-review, we summarize the progress of theoretical and simulation research of hydrodynamic instabilities in the ICF central hot-spot implosion in our group over the past decade. In order to obtain sufficient understanding of the growth of hydrodynamic instabilities in ICF, we first decompose the problem into different stages according to the implosion physics processes. The decomposed essential physics pro- cesses that are associated with ICF implosions, such as Rayleigh-Taylor instability （RTI）, Richtmyer-Meshkov instability （RMI）, Kelvin-Helmholtz instability （KHI）, convergent geometry effects, as well as perturbation feed-through are reviewed. Analyti- cal models in planar, cylindrical, and spherical geometries have been established to study different physical aspects, including density-gradient, interface-coupling, geometry, and convergent effects. The influence of ablation in the presence of preheating on the RTI has been extensively studied by numerical simulations. The KHI considering the ablation effect has been discussed in detail for the first time. A series of single-mode ablative RTI experiments has been performed on the Shenguang-II laser facility. The theoretical and simulation research provides us the physical insights of linear and weakly nonlinear growths, and nonlinear evolutions of the hydrodynamic instabilities in ICF implosions, which has directly supported the research of ICF ignition target design. The ICF hot-spot ignition implosion design that uses several controlling features, based on our current understanding of hydrodynamic instabilities, to address shell implosion stability, has been briefly described, several of which are novel.
基金supported by the Space Science Research Projects in Advance(SSRPA:O930143XM1)the Scientific Equipment Development and Research Project of Chinese Academy of Sciences(SEDRP:Y231411YB1)
文摘Due to high data rates and reliability,inter-satellite laser communication has developed rapidly in these days.However,the stability of the laser beam pointing is still a key technique which needs to be solved;otherwise,the beam pointing jitter noise would reduce the communication quality or,even worse,would make the inter-satellite laser communication impossible.For this purpose,a bench-top of the fine beam pointing control system has been built and tested for inter-satellite laser communication.The pointing offset of more than 100rad is produced by the steering mirror.With beam pointing control system turned on,the offset could be rapidly suppressed to lower than 100 nrad in less than 0.5 s.Moreover,the pointing stability can be kept at 40 nrad for yaw motion and 62 nrad for pitch motion,when the received beam jitter is set at 20rad.
基金Supported by National Natural Science Foundation of China under Grant Nos. 11275017 and 11173028
文摘In this paper,the improved canonical quantization method of the self dual field is given in order to overcome linear combination problem about the second class constraint and the first class constraint number maximization problem in the Dirac method.In the improved canonical quantization method,there are no artificial linear combination and the first class constraint number maximization problems,at the same time,the stability of the system is considered.Therefore,the improved canonical quantization method is more natural and easier accepted by people than the usual Dirac method.We use the improved canonical quantization method to realize the canonical quantization of the self dual field,which has relation with string theory successfully and the results are equal to the results by using the Dirac method.
