A series of study and investigation has been made on the basis of the theory of group work. The purpose is to study the effectiveness of group work in the interaction class, thus to attract more English teachers' att...A series of study and investigation has been made on the basis of the theory of group work. The purpose is to study the effectiveness of group work in the interaction class, thus to attract more English teachers' attention to seek for the new approach to the breakthrough of traditional English class mode.展开更多
Taking Heidaigou Open-cast Mine and Haerwusu Open-cast Mine in Zhungeer mining area as the research objects,this paper deeply analyzes the current mining status of the two mines.Based on the existing working line leng...Taking Heidaigou Open-cast Mine and Haerwusu Open-cast Mine in Zhungeer mining area as the research objects,this paper deeply analyzes the current mining status of the two mines.Based on the existing working line length,mining technology,transportation system,equipment configuration,transportation access and many other factors,it systematically discusses the feasibility of straightening the working line of adjacent open-cast mines.Through in-depth theoretical analysis,it establishes the mathematical model of impact indicators and cost calculation,and it is concluded that the work line straightening can be technically achieved.However,from the perspective of economic benefits,straightening the working line does not show obvious advantages.展开更多
The scattering of plane harmonic P and SV waves by a pair of vertically overlapping lined tunnels buried in an elastic half space is solved using a semi-analytic indirect boundary integration equation method. Then the...The scattering of plane harmonic P and SV waves by a pair of vertically overlapping lined tunnels buried in an elastic half space is solved using a semi-analytic indirect boundary integration equation method. Then the effect of the distance between the two tunnels, the stiffness and density of the lining material, and the incident frequency on the seismic response of the tunnels is investigated. Numerical results demonstrate that the dynamic interaction between the twin tunnels cannot be ignored and the lower tunnel has a significant shielding effect on the upper tunnel for high-frequency incident waves, resulting in great decrease of the dynamic hoop stress in the upper tunnel; for the low-frequency incident waves, in contrast, the lower tunnel can lead to amplification effect on the upper tunnel. It also reveals that the frequency-spectrum characteristics of dynamic stress of the lower tunnel are significantly different from those of the upper tunnel. In addition, for incident P waves in low-frequency region, the soft lining tunnels have significant amplification effect on the surface displacement amplitude, which is slightly larger than that of the corresponding single tunnel.展开更多
Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0...Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/ 10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with di-and hy-perploid YB strain of MDCK cell during 17 - 23 passages, with hyper- and hypoploid KA strain of MDCK cell during 6-8 passages, with hypoploid WB strain of MDCK cell on passage 6, with hyper-and hypoploid H strain of MDCK cell during 8-24 passages was 2/24, 6/10, 5/10 and 10/15, respectively. The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high(mcs + n) and lowest (mcs)passages was not more than 5 - 15% and the structure aberrations was generally 0 -3 %. These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome kary-otype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid. It is thus evident that MDCK cell of WB or H strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YB or KA strain can not be approved as substrate for the preparation of attenuated viral vaccines.展开更多
Marek’s disease (MD) is a lymphoproliferative disease of domestic chickens caused by Marek’s disease virus (MDV), an oncogenic and highly contagious α-herpesvirus. MD has been controlled by vaccination but sporadic...Marek’s disease (MD) is a lymphoproliferative disease of domestic chickens caused by Marek’s disease virus (MDV), an oncogenic and highly contagious α-herpesvirus. MD has been controlled by vaccination but sporadic outbreaks of MD still occur in some parts of the world. Efforts to improve vaccine efficacy have continued in both research communities and vaccine industries. We reported the host genetic variation affecting Marek’s disease vaccine-induced immunity in chickens earlier. In this study, we evaluated chicken lines, vaccines, and line by vaccine interaction on the protective efficacy of vaccination against MD. Specific pathogen free chickens from the relatively resistant line 63 and the highly susceptible line 72 were primarily used to evaluate the protection by three kinds of vaccines (rMd5ΔMeq, CVI988/Rispens, and HVT) upon challenge with a very virulent plus strain of MDV, vv+648A. Our data confirmed that both the chicken line and the vaccine significantly affected the protective efficacy of vaccination and showed that a chicken line by vaccine interaction, in most of the trials, also altered vaccine protective efficacy. More interestingly, although the protective index of all vaccine strains was higher in resistant than in susceptible line of chickens, the difference for HVT protection was striking and warrants further study. The findings may have important implications for vaccine development as well as for selective use of particular vaccines in specific lines of chickens to achieve maximum protection at minimized costs.展开更多
Starting from the variable separation approach, the algebraic soliton solution and the solution describing the interaction between line soliton and algebraic soliton are obtained by selecting appropriate seed solution...Starting from the variable separation approach, the algebraic soliton solution and the solution describing the interaction between line soliton and algebraic soliton are obtained by selecting appropriate seed solution for (2+1)-dimensional ANNV equation. The behaviors of interactions are discussed in detail both analytically and graphically. It is shown that there are two kinds of singular interactions between line soliton and algebraic soliton: 1) the resonant interaction where the algebraic soliton propagates together with the line soliton and persists infinitely; 2) the extremely repulsive interaction where the algebraic soliton affects the motion of the line soliton infinitely apart.展开更多
Plant flavonoids are polyphenolic compounds, commonly found in vegetables, fruits and many food sources that form a significant portion of our diet. These compounds act as anticancer and anti-proliferative but after i...Plant flavonoids are polyphenolic compounds, commonly found in vegetables, fruits and many food sources that form a significant portion of our diet. These compounds act as anticancer and anti-proliferative but after interaction with milk proteins they form complexes which become less effective than these compounds alone. Investigation has been conducted to delineate the action of some phenolic compounds of natural origin and complexes formed from interactions between phenolic compounds and milk proteins in three human tumors cell lines: Breast (MCF7), Liver (HePG2) and colon (HCT116), these interactions were studied by fourier transform infrared spectroscopy (FTIR). Phenolic compounds have positive effect on human cancer cell lines but after interaction with milk protein and forming complexes, they become less effective than phenolics and some time have negative effect and become pro-cancer;this interaction can be studied by (FTIR) to know which groups do this complex. The spectra were recorded under conditions generally applied in quantitative work. IR spectra were recorded in the region from 4000 - 250 cm–1, but the bands in the region 4000 - 1400 cm–1 were analyzed in detail, since they are characteristic of OH groups while NH groups appeared at (3000 - 4000 cm–1) of various protonic species that undergo hydrogen bonding interaction. Another region of interest was the region from 1800 - 1400 cm–1, characteristic of the bending vibrations of the same group. Since the bands in this region were wide and complex.展开更多
We present an alternative scheme for preparing the superpositions of coherent states along a straight line of a cavity field using degenerate atom-cavity field Raman interaction. In the scheme, a collection of A-type ...We present an alternative scheme for preparing the superpositions of coherent states along a straight line of a cavity field using degenerate atom-cavity field Raman interaction. In the scheme, a collection of A-type three-level atoms is orderly sent through the cavity to interact with the cavity field adjusted by a microwave source connected to it, followed by state-selective measurements. In this way, we can prepare the superpositions of several coherent states along a straight line with arbitrary weighting factors for the cavity field. In the scheme, the coherence of the atom-cavity system may be maintained and the second microwave field is unnecessary, which is prior to the previous scheme.展开更多
According to the railway transportation system's characteristics, a new cellular automaton model for the single- line railway system is presented in this paper. Based on this model, several simulations were done to i...According to the railway transportation system's characteristics, a new cellular automaton model for the single- line railway system is presented in this paper. Based on this model, several simulations were done to imitate the train operation under three working diagrams. From a different angle the results show how the organization of train operation impacts on the railway carrying capacity. By using the non-parallel train working diagram the influence of fast-train on slow-train is found to be the strongest. Many slow-trains have to wait in-between neighbouring stations to let the fast-train(s) pass through first. So the slow-train will advance like a wave propagating from the departure station to the arrival station. This also resembles the situation of a highway jammed traffic flow. Furthermore, the nonuniformity of travel times between the sections also greatly limits the railway carrying capacity. After converting the nonuniform sections into the sections with uniform travel times while the total travel time is kept unchanged, all three carrying capacities are improved greatly as shown by simulation. It also shows that the cellular automaton model is an effective and feasible way to investigate the railway transportation system.展开更多
Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What i...Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What information about learning do related problems returned by the system provide us? We answer the first question according to the didactic engineering, whose mode of validation is internal and based on the confrontation between an a priori analysis and an a posteriori analysis that relies on data from experiments in schools. We consider the student as a subject whose adaptation processes are conditioned by the problem and the possible interactions with the computer environment, and also by his knowledge, usually implicit, of the institutional norms that condition his relationship with geometry. Choosing a set of good problems within the system is therefore an essential element of the learning model. Since the source of a problem depends on the student’s actions with the computer tool, it is necessary to wait and see what are the related to problems that are returned to him before being able to identify patterns and assess the learning. With the simultaneity of collecting and analysing interactions in each class, we answer the second question according to a grounded theory analysis. By approaching the problems posed by the system and the designs in play at learning blockages, our analysis links the characteristics of problems to the design components in order to theorize on the decisional, epistemological, representational, didactic and instrumental aspects of the subject-milieu system in interaction.展开更多
Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters t...Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters the formation,resulting in widespread water-rock interaction.Deeply understanding such effects is required to optimize the production system.In this study,the mechanisms of water-rock interaction and the associated responses of shale fabric are systematically reviewed for working fluids such as neutral fluids,acid fluids,alkali fluids and oxidative fluids.It is shown that shale is generally rich in water-sensitive components such as clay minerals,acidsensitive components(like carbonate minerals),alkali-sensitive components(like quartz),oxidative-sensitive components(like organic matter and pyrite),which easily lead to change of rock fabric and mechanical properties owing to water-rock interaction.According to the results,oxidizing acid fluids and oxidizing fracturing fluids should be used to enhance shale gas recovery.This study also indicates that an aspect playing an important role in increasing cumulative gas production is the optimization of the maximum shut-in time based on the change point of the wellhead pressure drop rate.Another important influential factor to be considered is the control of the wellhead pressure considering the stress sensitivity and creep characteristics of the fracture network.展开更多
Since the 18th CPC National Congress,China has stood at a new historical point of departure,undergoing historical changes on top of the important achievements in development since the founding of the People’s Republi...Since the 18th CPC National Congress,China has stood at a new historical point of departure,undergoing historical changes on top of the important achievements in development since the founding of the People’s Republic and particularly since the adoption of the reform and open-up policy.Socialism with Chinese characteristics has entered a new展开更多
The nonlinear properties of lattice network-based(LNB) composite right-/left-handed transmission lines(CRLH TLs)with nonlinear capacitors are experimentally investigated.Harmonic generation,subharmonic generation,...The nonlinear properties of lattice network-based(LNB) composite right-/left-handed transmission lines(CRLH TLs)with nonlinear capacitors are experimentally investigated.Harmonic generation,subharmonic generation,and parametric excitation are clearly observed in an unbalanced LNB CRLH TL separately.While the balanced design of the novel nonlinear TL shows that the subharmonic generation and parametric processes can be suppressed,and almost the same power level of the higher harmonics can be achieved over a wide bandwidth range,which are difficult to find in conventional CRLH TLs.展开更多
Classroom interaction plays a critical role in language teaching and learning process.It involves both the teacher-students,and students-students.This article is intended to explore the vital significance of classroom...Classroom interaction plays a critical role in language teaching and learning process.It involves both the teacher-students,and students-students.This article is intended to explore the vital significance of classroom interaction in language learning process with the emphasis placed on the students' involvement in the classroom activities,furthermore,to discover whether the peers small-sized group work is a beneficial and irreplaceable form of classroom interaction.展开更多
This paper is committed to exploring the importance of learner learner interaction for language learning. It starts with a discussion of the roles that learner learner interaction plays in language learning from two p...This paper is committed to exploring the importance of learner learner interaction for language learning. It starts with a discussion of the roles that learner learner interaction plays in language learning from two points of view pedagogic and psycholinguistic, which is followed by a brief guideline for organizing group work in class.展开更多
The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this w...The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this work,multiscale metallurgical observations using scanning electron microscopy,electron-backscatter diffraction microscopy,and transmission electron microscopy were conducted to quantitatively characterize the microstructure of the machined subsurface.Next,to elucidate the factors that affect the formation of the refinement microstructure,the distributions of the deformation parameters(strain,strain rate,and temperature) in the machined subsurface were analyzed.A dislocation–twin interaction dynamic recrystallization mechanism for grain refinement during machining of Inconel 718 is proposed.Furthermore,microhardness evolution induced by grain refinement in the machined surface is evaluated.The results suggest that the gradient microstructure and the work hardening can be optimized by controlling the cutting parameters during turning of Inconel 718.展开更多
文摘A series of study and investigation has been made on the basis of the theory of group work. The purpose is to study the effectiveness of group work in the interaction class, thus to attract more English teachers' attention to seek for the new approach to the breakthrough of traditional English class mode.
文摘Taking Heidaigou Open-cast Mine and Haerwusu Open-cast Mine in Zhungeer mining area as the research objects,this paper deeply analyzes the current mining status of the two mines.Based on the existing working line length,mining technology,transportation system,equipment configuration,transportation access and many other factors,it systematically discusses the feasibility of straightening the working line of adjacent open-cast mines.Through in-depth theoretical analysis,it establishes the mathematical model of impact indicators and cost calculation,and it is concluded that the work line straightening can be technically achieved.However,from the perspective of economic benefits,straightening the working line does not show obvious advantages.
基金supported by the Tianjin Research Program of Application Foundation Advanced Technology (14JCYBJC21900)the National Natural Science Foundation of China under grants 51278327
文摘The scattering of plane harmonic P and SV waves by a pair of vertically overlapping lined tunnels buried in an elastic half space is solved using a semi-analytic indirect boundary integration equation method. Then the effect of the distance between the two tunnels, the stiffness and density of the lining material, and the incident frequency on the seismic response of the tunnels is investigated. Numerical results demonstrate that the dynamic interaction between the twin tunnels cannot be ignored and the lower tunnel has a significant shielding effect on the upper tunnel for high-frequency incident waves, resulting in great decrease of the dynamic hoop stress in the upper tunnel; for the low-frequency incident waves, in contrast, the lower tunnel can lead to amplification effect on the upper tunnel. It also reveals that the frequency-spectrum characteristics of dynamic stress of the lower tunnel are significantly different from those of the upper tunnel. In addition, for incident P waves in low-frequency region, the soft lining tunnels have significant amplification effect on the surface displacement amplitude, which is slightly larger than that of the corresponding single tunnel.
文摘Under the prerequisite that the incidence of cancer or tumor in negative-control nude mice inoculated subcutaneously with primary feline or canine kidney cell cultures purified in vitro at passage 3 was 0 (0/22) and 0 (0/10), respectively. The incidence of the progressively-growing malignant tumor(MT) in positive-control nude mice inoculated subcutaneously with Hela cell cultures of KB, X, or NM20/X strain was 10/ 10, 25/25 and 5/51, respectively. The results showed that the incidence of tumor in nude mice with di-and hy-perploid YB strain of MDCK cell during 17 - 23 passages, with hyper- and hypoploid KA strain of MDCK cell during 6-8 passages, with hypoploid WB strain of MDCK cell on passage 6, with hyper-and hypoploid H strain of MDCK cell during 8-24 passages was 2/24, 6/10, 5/10 and 10/15, respectively. The chromosomal analysis results showed that the ratio of difference in the rate of modal chromosome number between high(mcs + n) and lowest (mcs)passages was not more than 5 - 15% and the structure aberrations was generally 0 -3 %. These results proved that the genetic characteristics of chromosomal number of cell lines determines their tumorigenicity, but it is species-specific. MDCK line has tumorigenicity no matter what its chromosome kary-otype is, at least it has very low tumorigenicity even when its modal chromosome number is hypoploid. It is thus evident that MDCK cell of WB or H strain can be approved as substrate for the preparation of attenuated viral vaccines, but MDCK cell of YB or KA strain can not be approved as substrate for the preparation of attenuated viral vaccines.
文摘Marek’s disease (MD) is a lymphoproliferative disease of domestic chickens caused by Marek’s disease virus (MDV), an oncogenic and highly contagious α-herpesvirus. MD has been controlled by vaccination but sporadic outbreaks of MD still occur in some parts of the world. Efforts to improve vaccine efficacy have continued in both research communities and vaccine industries. We reported the host genetic variation affecting Marek’s disease vaccine-induced immunity in chickens earlier. In this study, we evaluated chicken lines, vaccines, and line by vaccine interaction on the protective efficacy of vaccination against MD. Specific pathogen free chickens from the relatively resistant line 63 and the highly susceptible line 72 were primarily used to evaluate the protection by three kinds of vaccines (rMd5ΔMeq, CVI988/Rispens, and HVT) upon challenge with a very virulent plus strain of MDV, vv+648A. Our data confirmed that both the chicken line and the vaccine significantly affected the protective efficacy of vaccination and showed that a chicken line by vaccine interaction, in most of the trials, also altered vaccine protective efficacy. More interestingly, although the protective index of all vaccine strains was higher in resistant than in susceptible line of chickens, the difference for HVT protection was striking and warrants further study. The findings may have important implications for vaccine development as well as for selective use of particular vaccines in specific lines of chickens to achieve maximum protection at minimized costs.
基金National Natural Science Foundation of China under Grant No.10675065the Science Research Foundation of the Education Department of Zhejiang Province under Grant No.20070979+1 种基金the Natural Science Foundation of Zhejiang Province under Grant No.Y604036the State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation\PLN0402
文摘Starting from the variable separation approach, the algebraic soliton solution and the solution describing the interaction between line soliton and algebraic soliton are obtained by selecting appropriate seed solution for (2+1)-dimensional ANNV equation. The behaviors of interactions are discussed in detail both analytically and graphically. It is shown that there are two kinds of singular interactions between line soliton and algebraic soliton: 1) the resonant interaction where the algebraic soliton propagates together with the line soliton and persists infinitely; 2) the extremely repulsive interaction where the algebraic soliton affects the motion of the line soliton infinitely apart.
文摘Plant flavonoids are polyphenolic compounds, commonly found in vegetables, fruits and many food sources that form a significant portion of our diet. These compounds act as anticancer and anti-proliferative but after interaction with milk proteins they form complexes which become less effective than these compounds alone. Investigation has been conducted to delineate the action of some phenolic compounds of natural origin and complexes formed from interactions between phenolic compounds and milk proteins in three human tumors cell lines: Breast (MCF7), Liver (HePG2) and colon (HCT116), these interactions were studied by fourier transform infrared spectroscopy (FTIR). Phenolic compounds have positive effect on human cancer cell lines but after interaction with milk protein and forming complexes, they become less effective than phenolics and some time have negative effect and become pro-cancer;this interaction can be studied by (FTIR) to know which groups do this complex. The spectra were recorded under conditions generally applied in quantitative work. IR spectra were recorded in the region from 4000 - 250 cm–1, but the bands in the region 4000 - 1400 cm–1 were analyzed in detail, since they are characteristic of OH groups while NH groups appeared at (3000 - 4000 cm–1) of various protonic species that undergo hydrogen bonding interaction. Another region of interest was the region from 1800 - 1400 cm–1, characteristic of the bending vibrations of the same group. Since the bands in this region were wide and complex.
文摘We present an alternative scheme for preparing the superpositions of coherent states along a straight line of a cavity field using degenerate atom-cavity field Raman interaction. In the scheme, a collection of A-type three-level atoms is orderly sent through the cavity to interact with the cavity field adjusted by a microwave source connected to it, followed by state-selective measurements. In this way, we can prepare the superpositions of several coherent states along a straight line with arbitrary weighting factors for the cavity field. In the scheme, the coherence of the atom-cavity system may be maintained and the second microwave field is unnecessary, which is prior to the previous scheme.
文摘According to the railway transportation system's characteristics, a new cellular automaton model for the single- line railway system is presented in this paper. Based on this model, several simulations were done to imitate the train operation under three working diagrams. From a different angle the results show how the organization of train operation impacts on the railway carrying capacity. By using the non-parallel train working diagram the influence of fast-train on slow-train is found to be the strongest. Many slow-trains have to wait in-between neighbouring stations to let the fast-train(s) pass through first. So the slow-train will advance like a wave propagating from the departure station to the arrival station. This also resembles the situation of a highway jammed traffic flow. Furthermore, the nonuniformity of travel times between the sections also greatly limits the railway carrying capacity. After converting the nonuniform sections into the sections with uniform travel times while the total travel time is kept unchanged, all three carrying capacities are improved greatly as shown by simulation. It also shows that the cellular automaton model is an effective and feasible way to investigate the railway transportation system.
文摘Our paper presents a project that involves two research questions: does the choice of a related problem by the tutorial system allow the problem solving process which is blocked for the student to be restarted? What information about learning do related problems returned by the system provide us? We answer the first question according to the didactic engineering, whose mode of validation is internal and based on the confrontation between an a priori analysis and an a posteriori analysis that relies on data from experiments in schools. We consider the student as a subject whose adaptation processes are conditioned by the problem and the possible interactions with the computer environment, and also by his knowledge, usually implicit, of the institutional norms that condition his relationship with geometry. Choosing a set of good problems within the system is therefore an essential element of the learning model. Since the source of a problem depends on the student’s actions with the computer tool, it is necessary to wait and see what are the related to problems that are returned to him before being able to identify patterns and assess the learning. With the simultaneity of collecting and analysing interactions in each class, we answer the second question according to a grounded theory analysis. By approaching the problems posed by the system and the designs in play at learning blockages, our analysis links the characteristics of problems to the design components in order to theorize on the decisional, epistemological, representational, didactic and instrumental aspects of the subject-milieu system in interaction.
基金Lijun,You,Innovative Research Project for Sichuan Youth Scientific and Technological Innovation(Grants No.2016TD0016)Qiuyang Cheng,Postdoctoral Research Project of Petrochina Southwest Oil and Gas Field Company(Grants No.20230304-13).
文摘Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters the formation,resulting in widespread water-rock interaction.Deeply understanding such effects is required to optimize the production system.In this study,the mechanisms of water-rock interaction and the associated responses of shale fabric are systematically reviewed for working fluids such as neutral fluids,acid fluids,alkali fluids and oxidative fluids.It is shown that shale is generally rich in water-sensitive components such as clay minerals,acidsensitive components(like carbonate minerals),alkali-sensitive components(like quartz),oxidative-sensitive components(like organic matter and pyrite),which easily lead to change of rock fabric and mechanical properties owing to water-rock interaction.According to the results,oxidizing acid fluids and oxidizing fracturing fluids should be used to enhance shale gas recovery.This study also indicates that an aspect playing an important role in increasing cumulative gas production is the optimization of the maximum shut-in time based on the change point of the wellhead pressure drop rate.Another important influential factor to be considered is the control of the wellhead pressure considering the stress sensitivity and creep characteristics of the fracture network.
文摘Since the 18th CPC National Congress,China has stood at a new historical point of departure,undergoing historical changes on top of the important achievements in development since the founding of the People’s Republic and particularly since the adoption of the reform and open-up policy.Socialism with Chinese characteristics has entered a new
基金supported by the National Natural Science Foundation of China(Grant Nos.61201030,60990322,and 60990320)the China Postdoctoral Science Foundation(Grant No.2012M521048)the Collegiate Natural Science Fund of Jiangsu Province,China(Grant No.12KJB140010)
文摘The nonlinear properties of lattice network-based(LNB) composite right-/left-handed transmission lines(CRLH TLs)with nonlinear capacitors are experimentally investigated.Harmonic generation,subharmonic generation,and parametric excitation are clearly observed in an unbalanced LNB CRLH TL separately.While the balanced design of the novel nonlinear TL shows that the subharmonic generation and parametric processes can be suppressed,and almost the same power level of the higher harmonics can be achieved over a wide bandwidth range,which are difficult to find in conventional CRLH TLs.
文摘Classroom interaction plays a critical role in language teaching and learning process.It involves both the teacher-students,and students-students.This article is intended to explore the vital significance of classroom interaction in language learning process with the emphasis placed on the students' involvement in the classroom activities,furthermore,to discover whether the peers small-sized group work is a beneficial and irreplaceable form of classroom interaction.
文摘This paper is committed to exploring the importance of learner learner interaction for language learning. It starts with a discussion of the roles that learner learner interaction plays in language learning from two points of view pedagogic and psycholinguistic, which is followed by a brief guideline for organizing group work in class.
基金financial support from the National Natural Science Foundation of China (No.51425503)the Major Science and Technology Program of High-end CNC Machine Tools and Basic Manufacturing Equipment of China (No.2014ZX04012014)supported by a grant from the Taishan Scholar Foundation of Shandong province (No.TS20130922)
文摘The microstructural changes in the machined surface layer of Ni-based super alloys essentially determine the final performance of the structural components of aerospace engines in which these alloys are used.In this work,multiscale metallurgical observations using scanning electron microscopy,electron-backscatter diffraction microscopy,and transmission electron microscopy were conducted to quantitatively characterize the microstructure of the machined subsurface.Next,to elucidate the factors that affect the formation of the refinement microstructure,the distributions of the deformation parameters(strain,strain rate,and temperature) in the machined subsurface were analyzed.A dislocation–twin interaction dynamic recrystallization mechanism for grain refinement during machining of Inconel 718 is proposed.Furthermore,microhardness evolution induced by grain refinement in the machined surface is evaluated.The results suggest that the gradient microstructure and the work hardening can be optimized by controlling the cutting parameters during turning of Inconel 718.