The present paper is finalized to show that the Science, even if considered in its two different Phenomenological Approaches at present known, is unable to assert that: “Thinks are like that”. This is because both t...The present paper is finalized to show that the Science, even if considered in its two different Phenomenological Approaches at present known, is unable to assert that: “Thinks are like that”. This is because both the two Scientific Approaches previously mentioned have not the property of “the perfect induction”. Consequently, although they can even reach an experimental confirmation of the theoretical results, and thus a “valid description” of the various phenomena of the surrounding world, such a description has not an “absolute value”. In fact, it always and only has an “operative validity”, that is, it exclusively and solely refers to an “experimental point of view”. This means that such an “operative validity” cannot represent the basis for a logical process characterized by a “perfect induction”. In addition, the Traditional Scientific Approach is also characterized by “Insoluble” Problems, “Intractable Problems”, Problems with “drifts”, which could generally be termed as “side effects”. On the other hand, the same com-possible Scientific Approach based on the Emerging Quality of Self-Organizing Systems, also presents its “Emerging Exits”. Consequently, none of the two mentioned scientific Approaches has the “gift” of “the perfect induction”. However, there are significant differences between the two. Differences that may “suggest” the most appropriate choice among them for an “operative point of view”. This conclusion will be com-proved by considering, with particular reference, both the “side effects”, which are related to the Traditional Approach and, on the other hand, the “Emerging Exits”, which specifically pertain to the new Scientific Approach based on the Emerging Quality of Self-Organizing Systems.展开更多
A naïve discussion of Fermat’s last theorem conundrum is described. The present theorem’s proof is grounded on the well-known properties of sums of powers of the sine and cosine functions, the Minkowski norm de...A naïve discussion of Fermat’s last theorem conundrum is described. The present theorem’s proof is grounded on the well-known properties of sums of powers of the sine and cosine functions, the Minkowski norm definition, and some vector-specific structures.展开更多
"The year of 2022 marked the70th anniversary of the founding of the China Council for the Promotion of International Trade(CCPIT),and it was also a milestone in the development history of trade promotion.Under th..."The year of 2022 marked the70th anniversary of the founding of the China Council for the Promotion of International Trade(CCPIT),and it was also a milestone in the development history of trade promotion.Under the strong leadership of the Central Committee of the Communist Party of China(CPC) with Comrade Xi Jinping at its core,the national trade promotion system faced up to difficulties,forged ahead.展开更多
(接上期)Context 3:EFL and ESOL learners at lower levels of achievement The third context relates largely to my own teaching in the adult EFL and ESC OL sectors in the UK,where I make use of PPP with classes of learner...(接上期)Context 3:EFL and ESOL learners at lower levels of achievement The third context relates largely to my own teaching in the adult EFL and ESC OL sectors in the UK,where I make use of PPP with classes of learners that tend towards the following characteristics:1.low levels of overall language proficiency;2.low language learning aptitude;3.low levels of literacy;4.low levels of learner autonomy;5.limited experience of formal classroom study;6.specific educational needs.展开更多
We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity tim...We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity time (PT) symmetry in the passive system has received much attention, and in this open three-state PT symmetric system, the incident wave is used as the effective gain instead of balancing the material gain and loss. We analyze the variation of coherent perfect absorption of this system with the coupling coefficient of the system by simulation.展开更多
The two-dimensional magnetic van der Waals heterojunctions have opened unprecedented opportunities to explore new physics due to their potential for spintronic applications.Here,combing density functional theory with ...The two-dimensional magnetic van der Waals heterojunctions have opened unprecedented opportunities to explore new physics due to their potential for spintronic applications.Here,combing density functional theory with non-equilibrium Green’s function technique.展开更多
The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we inve...The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we investigate the spatial quantum coherent modulation effect with PHVVB based on the atomic medium,and we observe the absorption characteristic of the PHVVB with different TCs under variant magnetic fields.We find that the transmission spectrum linewidth of PHVVB can be effectively maintained regardless of the TC.Still,the width of transmission peaks increases slightly as the beam size expands in hot atomic vapor.This distinctive quantum coherence phenomenon,demonstrated by the interaction of an atomic medium with a hybrid vector-structured beam,might be anticipated to open up new opportunities for quantum coherence modulation and accurate magnetic field measurement.展开更多
In this work,a numerical study of the effects of soil-structure interaction(SSI)and granular material-structure interaction(GSI)on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducte...In this work,a numerical study of the effects of soil-structure interaction(SSI)and granular material-structure interaction(GSI)on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducted.A series of incremental dynamic analyses(IDA)are performed on a case of large reinforced concrete silo using 10 seismic recordings.The IDA results are given by two average IDA capacity curves,which are represented,as well as the seismic capacity of the studied structure,with and without a consideration of the SSI while accounting for the effect of GSI.These curves are used to quantify and evaluate the damage of the studied silo by utilizing two damage indices,one based on dissipated energy and the other on displacement and dissipated energy.The cumulative energy dissipation curves obtained by the average IDA capacity curves with and without SSI are presented as a function of the base shear,and these curves allow one to obtain the two critical points and the different limit states of the structure.It is observed that the SSI and GSI significantly influence the seismic response and capacity of the studied structure,particularly at higher levels of PGA.Moreover,the effect of the SSI reduces the damage index of the studied structure by 4%.展开更多
The commitment to embracing the world with virtue,in addition to being the spiritual pillar of Chinese civilization,also holds great significance for political progress in the new era.THE phrase“embracing the world w...The commitment to embracing the world with virtue,in addition to being the spiritual pillar of Chinese civilization,also holds great significance for political progress in the new era.THE phrase“embracing the world with virtue”(厚德载物)is taken from a line in the nearly 3,000-year-old book of The Book of Changes which reads,“As heaven maintains vigor through movement,a gentleman should constantly strive for self-perfection.Like the earth,which is genial and generous,a gentleman should embrace the world with virtue.”展开更多
Afirst-class forwarding agent company approved by the Ministry of Foreign Trade and Economic Cooperation,the Ministry of Communication, the General Customs and the Civil Aviation Administration of China, the Shanghai ...Afirst-class forwarding agent company approved by the Ministry of Foreign Trade and Economic Cooperation,the Ministry of Communication, the General Customs and the Civil Aviation Administration of China, the Shanghai Jinhai Jieya International Forwarding Co. Ltd comprises the Shanghai Haigang Industrial General Company,Shanghai Jin Jiang Associated Corporation (Group) and Hongkong Jieya Air Freight Forwarding Corporation, in the form of a joint venture.展开更多
The perfect jacket for anyone looking for a technical allrounder.The Alto Guide is perfect for everything from day hikes to first adventures in mountaineering.Durable stretch Mammut DRYtechnology^(TM)Pro 3-layer mater...The perfect jacket for anyone looking for a technical allrounder.The Alto Guide is perfect for everything from day hikes to first adventures in mountaineering.Durable stretch Mammut DRYtechnology^(TM)Pro 3-layer material is breathable,waterproof and PFC-free.Multiple features,which include backpack-compatible front pockets,a helmet-compatible hood with reinforced peak,and a 2-way zipper for easy climbing harness access,make the hard-wearing Alto Guide an ideal weatherproof jacket for mountain and hiking tours.A smart choice for your mountain sport adventures:technical,functional and durable.展开更多
Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whe...Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whenever there is an imperfect correlation between returns risk is reduced by maintaining only a portion of wealth in any asset, or by selecting a portfolio according to expected returns and correlations between returns. The major improvement of the portfolio approaches over prior received theory is the incorporation of 1) the riskiness of an asset and 2) the addition from investing in any asset. The theme of this paper is to discuss how to propose a new mathematical model like that provided by Markowitz, which helps in choosing a nearly perfect portfolio and an efficient input/output. Besides applying this model to reality, the researcher uses game theory, stochastic and linear programming to provide the model proposed and then uses this model to select a perfect portfolio in the Cairo Stock Exchange. The results are fruitful and the researcher considers this model a new contribution to previous models.展开更多
The nonsplitting perfectly matched layer (NPML) absorbing boundary condition (ABC) was first provided by Wang and Tang (2003) for the finite-difference simulation of elastic wave propagation in solids. In this p...The nonsplitting perfectly matched layer (NPML) absorbing boundary condition (ABC) was first provided by Wang and Tang (2003) for the finite-difference simulation of elastic wave propagation in solids. In this paper, the method is developed to extend the NPML to simulating elastic wave propagation in poroelastic media. Biot's equations are discretized and approximated to a staggered-grid by applying a fourth-order accurate central difference in space and a second-order accurate central difference in time. A cylindrical twolayer seismic model and a borehole model are chosen to validate the effectiveness of the NPML. The results show that the numerical solutions agree well with the solutions of the discrete wavenumber (DW) method.展开更多
When simulating seismic wave propagation in free space, it is essential to introduce absorbing boundary conditions to eliminate reflections from artificially trtmcated boundaries. In this paper, a damping factor refer...When simulating seismic wave propagation in free space, it is essential to introduce absorbing boundary conditions to eliminate reflections from artificially trtmcated boundaries. In this paper, a damping factor referred to as the Gaussian dmping factor is proposed. The Gaussian damping factor is based on the idea of perfectly matched layers (PMLs). This work presents a detailed analysis of the theoretical foundations and advantages of the Gaussian damping factor. Additionally, numerical experiments for the simulation of seismic waves are presented based on two numerical models: a homogeneous model and a multi-layer model. The results show that the proposed factor works better. The Gaussian damping factor achieves a higher Signal-to-Noise Ratio (SNR) than previously used factors when using same number of PMLs, and requires less PMLs than other methods to achieve an identical SNR.展开更多
The quantum state transmission through the medium of high-dimensional many-particle system (boson or spinless fermion) is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonia...The quantum state transmission through the medium of high-dimensional many-particle system (boson or spinless fermion) is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonian matches the symmetry of a fermion or boson system in a certain fashion, a perfect quantum state transfer can be implemented without any operation on the medium with pre-engineered nearest neighbor (NN). We also study a simple but realistic near half-filled tight-bindlng fermion system wlth uniform NN hopping integral. We show that an arbitrary many-particle state near the fermi surface can be perfectly transferred to its translational counterpart.展开更多
In 2012,we investigated the possible molecular states composed of two charmed mesons[Phys.Rev.D 88(2013)114008;2012 arXiv:1211.5007[hep-ph]].The D^(*)D𝐷system with the quantum numbers of I(J^(P))=0(1^(+))was f...In 2012,we investigated the possible molecular states composed of two charmed mesons[Phys.Rev.D 88(2013)114008;2012 arXiv:1211.5007[hep-ph]].The D^(*)D𝐷system with the quantum numbers of I(J^(P))=0(1^(+))was found to be a good candidate of the loosely bound molecular state.This state is very close to theD*D threshold with a binding energy around 0.47 MeV.This prediction was confirmed by the new LHCb observation of𝑇T^(+)_(cc)[see Franz Muheim’s talk at the European Physical Society conference on high energy physics 2021].展开更多
Concept-based instruction(C-BI)has proven to be effective in improving students’command of grammar items used out of context by offering the students revision lessons,but its effect in teaching newly-introduced gramm...Concept-based instruction(C-BI)has proven to be effective in improving students’command of grammar items used out of context by offering the students revision lessons,but its effect in teaching newly-introduced grammar items in a complex context of a specific genre remains unclear.To probe C-BI’s effect on students’use of the past simple and present perfect tenses out of context and in the context of a narrative by its description of the grammar concept in its materialization,that is,the Schemas of a Complete Orienting Basis of an Action(SCOBAs),we taught the two tenses to 40 eighth-graders in a Chinese middle school in our three-week teaching experiment.The qualitative and quantitative analysis of the results shows that i)in both out-ofcontext use and in-context use,accuracy of using the target tenses is higher after C-BI intervention;ii)by improving their conceptual knowledge through C-BI,the students are helped to pin down reference time and are hence more certain in using the target tenses.Moreover,they are encouraged to use the newly-introduced tenses in the complex context of the narrative genre;iii)both in simple contexts or complex contexts,the SCOBAs are effective in helping students navigate the learning task and determine their intended meaning by establishing temporal reference in the context.展开更多
This article presents very original and relatively brief or very brief proofs about of two famous problems: 1) Are there any odd perfect numbers? and 2) “Fermat’s last theorem: A new proof of theorem and its general...This article presents very original and relatively brief or very brief proofs about of two famous problems: 1) Are there any odd perfect numbers? and 2) “Fermat’s last theorem: A new proof of theorem and its generalization”. They are achieved with elementary mathematics. This is why these proofs can be easily understood by any mathematician or anyone who knows basic mathematics. Note that, in both problems, proof by contradiction was used as a method of proof. The first of the two problems to date has not been resolved. Its proof is completely original and was not based on the work of other researchers. On the contrary, it was based on a simple observation that all natural divisors of a positive integer appear in pairs. The aim of the first work is to solve one of the unsolved, for many years, problems of the mathematics which belong to the field of number theory. I believe that if the present proof is recognized by the mathematical community, it may signal a different way of solving unsolved problems. For the second problem, it is very important the fact that it is generalized to an arbitrarily large number of variables. This generalization is essentially a new theorem in the field of the number theory. To the classical problem, two solutions are given, which are presented in the chronological order in which they were achieved. <em>Note that the second solution is very short and does not exceed one and a half pages</em>. This leads me to believe that Fermat, as a great mathematician was not lying and that he had probably solved the problem, as he stated in his historic its letter, with a correspondingly brief solution. <em>To win the bet on the question of whether Fermat was telling truth or lying, go immediately to the end of this article before the General Conclusions.</em>展开更多
Translation is a complex and misleading field of knowledge. Many people consider that some translators are incredibly skillful and that "perfect" translation truly exists. While this fantasy is so appealing,...Translation is a complex and misleading field of knowledge. Many people consider that some translators are incredibly skillful and that "perfect" translation truly exists. While this fantasy is so appealing, we must know that such things as perfect translation and omni- scient translators do not exist, and the reasons are often too subtle for people to realize. Even though the prospect of translation seems to be a little bit frustrating, it is not a hopeless field where we can still make progress. In this essay, I will first introduce what are "omniscient translator" and "perfect translation", and then I will analyze why they do not exist in real world, and why many people take these two fantasies for granted. At last, I will tell that what we can do to get improvement in translation.展开更多
文摘The present paper is finalized to show that the Science, even if considered in its two different Phenomenological Approaches at present known, is unable to assert that: “Thinks are like that”. This is because both the two Scientific Approaches previously mentioned have not the property of “the perfect induction”. Consequently, although they can even reach an experimental confirmation of the theoretical results, and thus a “valid description” of the various phenomena of the surrounding world, such a description has not an “absolute value”. In fact, it always and only has an “operative validity”, that is, it exclusively and solely refers to an “experimental point of view”. This means that such an “operative validity” cannot represent the basis for a logical process characterized by a “perfect induction”. In addition, the Traditional Scientific Approach is also characterized by “Insoluble” Problems, “Intractable Problems”, Problems with “drifts”, which could generally be termed as “side effects”. On the other hand, the same com-possible Scientific Approach based on the Emerging Quality of Self-Organizing Systems, also presents its “Emerging Exits”. Consequently, none of the two mentioned scientific Approaches has the “gift” of “the perfect induction”. However, there are significant differences between the two. Differences that may “suggest” the most appropriate choice among them for an “operative point of view”. This conclusion will be com-proved by considering, with particular reference, both the “side effects”, which are related to the Traditional Approach and, on the other hand, the “Emerging Exits”, which specifically pertain to the new Scientific Approach based on the Emerging Quality of Self-Organizing Systems.
文摘A naïve discussion of Fermat’s last theorem conundrum is described. The present theorem’s proof is grounded on the well-known properties of sums of powers of the sine and cosine functions, the Minkowski norm definition, and some vector-specific structures.
文摘"The year of 2022 marked the70th anniversary of the founding of the China Council for the Promotion of International Trade(CCPIT),and it was also a milestone in the development history of trade promotion.Under the strong leadership of the Central Committee of the Communist Party of China(CPC) with Comrade Xi Jinping at its core,the national trade promotion system faced up to difficulties,forged ahead.
文摘(接上期)Context 3:EFL and ESOL learners at lower levels of achievement The third context relates largely to my own teaching in the adult EFL and ESC OL sectors in the UK,where I make use of PPP with classes of learners that tend towards the following characteristics:1.low levels of overall language proficiency;2.low language learning aptitude;3.low levels of literacy;4.low levels of learner autonomy;5.limited experience of formal classroom study;6.specific educational needs.
文摘We investigate the phenomenon of coherent perfect absorption in a high-order system with three passive resonators coupled to a super-surface to form this three-state coherent perfect absorber. The effective parity time (PT) symmetry in the passive system has received much attention, and in this open three-state PT symmetric system, the incident wave is used as the effective gain instead of balancing the material gain and loss. We analyze the variation of coherent perfect absorption of this system with the coupling coefficient of the system by simulation.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3505301)the Natural Science Basic Research Program of Shanxi(Grant No.20210302124252)the Innovation Project For Teaching Reform of Shanxi(Grant No.J20230616)。
文摘The two-dimensional magnetic van der Waals heterojunctions have opened unprecedented opportunities to explore new physics due to their potential for spintronic applications.Here,combing density functional theory with non-equilibrium Green’s function technique.
基金Project supported by the Youth Innovation Promotion Association CASState Key Laboratory of Transient Optics and Photonics Open Topics (Grant No. SKLST202222)
文摘The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we investigate the spatial quantum coherent modulation effect with PHVVB based on the atomic medium,and we observe the absorption characteristic of the PHVVB with different TCs under variant magnetic fields.We find that the transmission spectrum linewidth of PHVVB can be effectively maintained regardless of the TC.Still,the width of transmission peaks increases slightly as the beam size expands in hot atomic vapor.This distinctive quantum coherence phenomenon,demonstrated by the interaction of an atomic medium with a hybrid vector-structured beam,might be anticipated to open up new opportunities for quantum coherence modulation and accurate magnetic field measurement.
文摘In this work,a numerical study of the effects of soil-structure interaction(SSI)and granular material-structure interaction(GSI)on the nonlinear response and seismic capacity of flat-bottomed storage silos is conducted.A series of incremental dynamic analyses(IDA)are performed on a case of large reinforced concrete silo using 10 seismic recordings.The IDA results are given by two average IDA capacity curves,which are represented,as well as the seismic capacity of the studied structure,with and without a consideration of the SSI while accounting for the effect of GSI.These curves are used to quantify and evaluate the damage of the studied silo by utilizing two damage indices,one based on dissipated energy and the other on displacement and dissipated energy.The cumulative energy dissipation curves obtained by the average IDA capacity curves with and without SSI are presented as a function of the base shear,and these curves allow one to obtain the two critical points and the different limit states of the structure.It is observed that the SSI and GSI significantly influence the seismic response and capacity of the studied structure,particularly at higher levels of PGA.Moreover,the effect of the SSI reduces the damage index of the studied structure by 4%.
文摘The commitment to embracing the world with virtue,in addition to being the spiritual pillar of Chinese civilization,also holds great significance for political progress in the new era.THE phrase“embracing the world with virtue”(厚德载物)is taken from a line in the nearly 3,000-year-old book of The Book of Changes which reads,“As heaven maintains vigor through movement,a gentleman should constantly strive for self-perfection.Like the earth,which is genial and generous,a gentleman should embrace the world with virtue.”
文摘Afirst-class forwarding agent company approved by the Ministry of Foreign Trade and Economic Cooperation,the Ministry of Communication, the General Customs and the Civil Aviation Administration of China, the Shanghai Jinhai Jieya International Forwarding Co. Ltd comprises the Shanghai Haigang Industrial General Company,Shanghai Jin Jiang Associated Corporation (Group) and Hongkong Jieya Air Freight Forwarding Corporation, in the form of a joint venture.
文摘The perfect jacket for anyone looking for a technical allrounder.The Alto Guide is perfect for everything from day hikes to first adventures in mountaineering.Durable stretch Mammut DRYtechnology^(TM)Pro 3-layer material is breathable,waterproof and PFC-free.Multiple features,which include backpack-compatible front pockets,a helmet-compatible hood with reinforced peak,and a 2-way zipper for easy climbing harness access,make the hard-wearing Alto Guide an ideal weatherproof jacket for mountain and hiking tours.A smart choice for your mountain sport adventures:technical,functional and durable.
文摘Modern financial theory, commonly known as portfolio theory, provides an analytical framework for the investment decision to be made under uncertainty. It is a well-established proposition in portfolio theory that whenever there is an imperfect correlation between returns risk is reduced by maintaining only a portion of wealth in any asset, or by selecting a portfolio according to expected returns and correlations between returns. The major improvement of the portfolio approaches over prior received theory is the incorporation of 1) the riskiness of an asset and 2) the addition from investing in any asset. The theme of this paper is to discuss how to propose a new mathematical model like that provided by Markowitz, which helps in choosing a nearly perfect portfolio and an efficient input/output. Besides applying this model to reality, the researcher uses game theory, stochastic and linear programming to provide the model proposed and then uses this model to select a perfect portfolio in the Cairo Stock Exchange. The results are fruitful and the researcher considers this model a new contribution to previous models.
基金This research was supported by Natural Science Foundation of China (No. 403740043).
文摘The nonsplitting perfectly matched layer (NPML) absorbing boundary condition (ABC) was first provided by Wang and Tang (2003) for the finite-difference simulation of elastic wave propagation in solids. In this paper, the method is developed to extend the NPML to simulating elastic wave propagation in poroelastic media. Biot's equations are discretized and approximated to a staggered-grid by applying a fourth-order accurate central difference in space and a second-order accurate central difference in time. A cylindrical twolayer seismic model and a borehole model are chosen to validate the effectiveness of the NPML. The results show that the numerical solutions agree well with the solutions of the discrete wavenumber (DW) method.
基金supported by the National Natural Science Foundation of China(No. 61072118)
文摘When simulating seismic wave propagation in free space, it is essential to introduce absorbing boundary conditions to eliminate reflections from artificially trtmcated boundaries. In this paper, a damping factor referred to as the Gaussian dmping factor is proposed. The Gaussian damping factor is based on the idea of perfectly matched layers (PMLs). This work presents a detailed analysis of the theoretical foundations and advantages of the Gaussian damping factor. Additionally, numerical experiments for the simulation of seismic waves are presented based on two numerical models: a homogeneous model and a multi-layer model. The results show that the proposed factor works better. The Gaussian damping factor achieves a higher Signal-to-Noise Ratio (SNR) than previously used factors when using same number of PMLs, and requires less PMLs than other methods to achieve an identical SNR.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 90203018, 10474104, and 10447133, and the Knowledge Innovation Program (KIP) of the Chinese Academy of Sciences, the National Fundamental Research Program of China under Grant No. 2001CB309310
文摘The quantum state transmission through the medium of high-dimensional many-particle system (boson or spinless fermion) is generally studied with a symmetry analysis. We discover that, if the spectrum of a Hamiltonian matches the symmetry of a fermion or boson system in a certain fashion, a perfect quantum state transfer can be implemented without any operation on the medium with pre-engineered nearest neighbor (NN). We also study a simple but realistic near half-filled tight-bindlng fermion system wlth uniform NN hopping integral. We show that an arbitrary many-particle state near the fermi surface can be perfectly transferred to its translational counterpart.
基金Supported by the China National Funds for Distinguished Young Scientists(Grant No.11825503)the National Key Research and Development Program of China(Grant No.2020YFA0406400)+1 种基金the 111 Project(Grant No.B20063)the National Natural Science Foundation of China(Grant No.11975033,12070131001,and 12047501).
文摘In 2012,we investigated the possible molecular states composed of two charmed mesons[Phys.Rev.D 88(2013)114008;2012 arXiv:1211.5007[hep-ph]].The D^(*)D𝐷system with the quantum numbers of I(J^(P))=0(1^(+))was found to be a good candidate of the loosely bound molecular state.This state is very close to theD*D threshold with a binding energy around 0.47 MeV.This prediction was confirmed by the new LHCb observation of𝑇T^(+)_(cc)[see Franz Muheim’s talk at the European Physical Society conference on high energy physics 2021].
文摘Concept-based instruction(C-BI)has proven to be effective in improving students’command of grammar items used out of context by offering the students revision lessons,but its effect in teaching newly-introduced grammar items in a complex context of a specific genre remains unclear.To probe C-BI’s effect on students’use of the past simple and present perfect tenses out of context and in the context of a narrative by its description of the grammar concept in its materialization,that is,the Schemas of a Complete Orienting Basis of an Action(SCOBAs),we taught the two tenses to 40 eighth-graders in a Chinese middle school in our three-week teaching experiment.The qualitative and quantitative analysis of the results shows that i)in both out-ofcontext use and in-context use,accuracy of using the target tenses is higher after C-BI intervention;ii)by improving their conceptual knowledge through C-BI,the students are helped to pin down reference time and are hence more certain in using the target tenses.Moreover,they are encouraged to use the newly-introduced tenses in the complex context of the narrative genre;iii)both in simple contexts or complex contexts,the SCOBAs are effective in helping students navigate the learning task and determine their intended meaning by establishing temporal reference in the context.
文摘This article presents very original and relatively brief or very brief proofs about of two famous problems: 1) Are there any odd perfect numbers? and 2) “Fermat’s last theorem: A new proof of theorem and its generalization”. They are achieved with elementary mathematics. This is why these proofs can be easily understood by any mathematician or anyone who knows basic mathematics. Note that, in both problems, proof by contradiction was used as a method of proof. The first of the two problems to date has not been resolved. Its proof is completely original and was not based on the work of other researchers. On the contrary, it was based on a simple observation that all natural divisors of a positive integer appear in pairs. The aim of the first work is to solve one of the unsolved, for many years, problems of the mathematics which belong to the field of number theory. I believe that if the present proof is recognized by the mathematical community, it may signal a different way of solving unsolved problems. For the second problem, it is very important the fact that it is generalized to an arbitrarily large number of variables. This generalization is essentially a new theorem in the field of the number theory. To the classical problem, two solutions are given, which are presented in the chronological order in which they were achieved. <em>Note that the second solution is very short and does not exceed one and a half pages</em>. This leads me to believe that Fermat, as a great mathematician was not lying and that he had probably solved the problem, as he stated in his historic its letter, with a correspondingly brief solution. <em>To win the bet on the question of whether Fermat was telling truth or lying, go immediately to the end of this article before the General Conclusions.</em>
文摘Translation is a complex and misleading field of knowledge. Many people consider that some translators are incredibly skillful and that "perfect" translation truly exists. While this fantasy is so appealing, we must know that such things as perfect translation and omni- scient translators do not exist, and the reasons are often too subtle for people to realize. Even though the prospect of translation seems to be a little bit frustrating, it is not a hopeless field where we can still make progress. In this essay, I will first introduce what are "omniscient translator" and "perfect translation", and then I will analyze why they do not exist in real world, and why many people take these two fantasies for granted. At last, I will tell that what we can do to get improvement in translation.