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The study of English perfective aspect
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作者 YU Qiao-fen WANG Jian-ying 《Sino-US English Teaching》 2010年第6期28-31,共4页
Through this research, on the basis of English-Chinese and Chinese-English parallel corpora, the following conclusion tries to be drawn: In English, the perfect may not be used together with the specific time of the ... Through this research, on the basis of English-Chinese and Chinese-English parallel corpora, the following conclusion tries to be drawn: In English, the perfect may not be used together with the specific time of the past situation. In contrast to English, Chinese does not have perfect constructions. English perfective aspect is an actual aspect indication: duration and completion of an action or situation. According to different reference time, the actual aspect can be divided into past actuality, present actuality and future actuality. This paper will undoubtedly contribute to the study of tense-aspect in Chinese. The study of English perfective aspect is conducive to the comparative study and translation of aspect in English and Chinese. 展开更多
关键词 perfective aspect different reference times past actuality present actuality future actuality translation of aspect
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Spatial quantum coherent modulation with perfect hybrid vector vortex beam based on atomic medium
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作者 马燕 杨欣 +6 位作者 常虹 杨鑫琪 曹明涛 张晓斐 高宏 董瑞芳 张首刚 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期360-364,共5页
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
关键词 perfect hybrid vector vortex beam topological charge quantum coherence optical manipulation
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Numerical investigation of the effects of soil-structure and granular material-structure interaction on the seismic response of a flat-bottom reinforced concrete silo
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作者 Sonia Benkhellat Mohammed Kadri Abdelghani Seghir 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期609-623,共15页
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
关键词 reinforced concrete silo perfectly matched layers soil-structure interaction granular material-structure interaction effective seismic input method damage index
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Unconditionally stable Crank-Nicolson algorithm with enhanced absorption for rotationally symmetric multi-scale problems in anisotropic magnetized plasma
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作者 WEN Yi WANG Junxiang XU Hongbing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期65-73,共9页
Large calculation error can be formed by directly employing the conventional Yee’s grid to curve surfaces.In order to alleviate such condition,unconditionally stable CrankNicolson Douglas-Gunn(CNDG)algorithm with is ... Large calculation error can be formed by directly employing the conventional Yee’s grid to curve surfaces.In order to alleviate such condition,unconditionally stable CrankNicolson Douglas-Gunn(CNDG)algorithm with is proposed for rotationally symmetric multi-scale problems in anisotropic magnetized plasma.Within the CNDG algorithm,an alternative scheme for the simulation of anisotropic plasma is proposed in body-of-revolution domains.Convolutional perfectly matched layer(CPML)formulation is proposed to efficiently solve the open region problems.Numerical example is carried out for the illustration of effectiveness including the efficiency,resources,and absorption.Through the results,it can be concluded that the proposed scheme shows considerable performance during the simulation. 展开更多
关键词 anisotropic magnetized plasma body-of-revolution(BOR) Crank-Nicolson Douglas-Gunn(CNDG) finite-difference time-domain(FDTD) perfectly matched layer(PML) rotationally symmetric multi-scale problems
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Perfect 1-k Matchings of Bipartite Graphs
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作者 Wenduan Dai Yan Liu Yanfang Wu 《Open Journal of Discrete Mathematics》 2024年第4期43-53,共11页
Let k be a positive integer and G a bipartite graph with bipartition (X,Y). A perfect 1-k matching is an edge subset M of G such that each vertex in Y is incident with exactly one edge in M and each vertex in X is inc... Let k be a positive integer and G a bipartite graph with bipartition (X,Y). A perfect 1-k matching is an edge subset M of G such that each vertex in Y is incident with exactly one edge in M and each vertex in X is incident with exactly k edges in M. A perfect 1-k matching is an optimal semi-matching related to the load-balancing problem, where a semi-matching is an edge subset M such that each vertex in Y is incident with exactly one edge in M, and a vertex in X can be incident with an arbitrary number of edges in M. In this paper, we give three sufficient and necessary conditions for the existence of perfect 1-k matchings and for the existence of 1-k matchings covering | X |−dvertices in X, respectively, and characterize k-elementary bipartite graph which is a graph such that the subgraph induced by all k-allowed edges is connected, where an edge is k-allowed if it is contained in a perfect 1-k matching. 展开更多
关键词 Bipartite Graph Semi-Matching Perfect 1-k Matching k-Elementary Graph
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Artificial Intelligence as a Check on Logic
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作者 Edwin Eugene Klingman 《Journal of Applied Mathematics and Physics》 2024年第9期3148-3162,共15页
Math and physics proceed from assumptions to conclusions via a logical path. Artificial intelligence possesses the ability to follow logic, herein specifically applied to the problem of defining ontologically real 2D ... Math and physics proceed from assumptions to conclusions via a logical path. Artificial intelligence possesses the ability to follow logic, herein specifically applied to the problem of defining ontologically real 2D manifolds in a 3D continuum. Vortices and tori in fluids exhibit effective 2D surfaces, which, treated as manifolds, allow application of calculus on the boundaries of the structures. Recent papers in primordial field theory (PFT) have employed Calabi-Yau geometry and topology to develop a fermion structure. We desire a logical justification of this application and herein explore the use of artificial intelligence to assist in logic verification. A proof is outlined by the author and formalized by the AI. 展开更多
关键词 AI CALABI-YAU YANG-MILLS Perfect Fluid Fermion Structure MANIFOLD 3D Continuum
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你是什么样的人
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作者 Ruth Devlin 《空中英语教室(初级版.大家说英语)》 2024年第6期16-19,56,51,52,共7页
Whatkind ofa person areyou?Do any of thesewords describe you?Maybe you are kind.You are friendly and generous.Are you helpful?Do you often do things for others?Maybe you are patient.You can wait.Youdon't mind.But ... Whatkind ofa person areyou?Do any of thesewords describe you?Maybe you are kind.You are friendly and generous.Are you helpful?Do you often do things for others?Maybe you are patient.You can wait.Youdon't mind.But noone isperfect.Maybeyou are selfish sometimes. 展开更多
关键词 PERFECT friendly SOMETIMES
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Upgrading jackets for spring
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作者 Zhao Xinhua 《China Textile》 2024年第2期11-11,共1页
When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can sti... When the gentle breeze of spring starts to fill the air,it's often a time of transition,where the chill of winter gives way to the warmth of the coming season.However,for those who love the outdoors,spring can still present its own set of challenges,especially when it's time to choose the right jacket.Whether you're hiking in the hills,exploring the trails,or just taking a leisurely walk in the park,having a jacket that offers the perfect blend of warmth,comfort,and breathability is crucial.We'll delve into the various options available for jackets that are perfect for the outdoors in spring. 展开更多
关键词 SPRING JACKET PERFECT
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遵义会议会址
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作者 高菲菲 《疯狂英语(初中天地)》 2024年第5期61-63,共3页
As a city of red tourism,the site of the Zunyi Conference is a perfect place for patriotic(爱国主义的) education,where you could truly experience the greatness of the Communist Party of China(CPC).The site of the Zuny... As a city of red tourism,the site of the Zunyi Conference is a perfect place for patriotic(爱国主义的) education,where you could truly experience the greatness of the Communist Party of China(CPC).The site of the Zunyi Conference is located in Ziyi Road No.96,Honghuagang District,Zunyi City,Guizhou Province.It was built in the 1930s,and originally was a residential mansion(宅第)of Bai Huizhang,a commander of the second division(师)of the Guizhou Army.The mansion consists of the main building and several cross yards(跨院),and the main building,a two-story structure with Chinese and Western style has eight shops facing the street. 展开更多
关键词 GUIZHOU EDUCATION PERFECT
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罗莎琳德·富兰克林:诺贝尔奖背后的英雄
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作者 孙启禄 《疯狂英语(新读写)》 2024年第7期28-31,76,共5页
Rosalind Franklin,one of the greatest scientists of her time,was a British-born perfectionist.While she had a reputation for being somewhat reserved and difficult to get along with,those who knew her well found her to... Rosalind Franklin,one of the greatest scientists of her time,was a British-born perfectionist.While she had a reputation for being somewhat reserved and difficult to get along with,those who knew her well found her to be outgoing and loyal.Franklin's brilliance shone through in her work,particularly in the field of X-ray crystallography(晶体学),an imaging technique that revealed molecular structures based on scattered X-ray beams.Her early research on the micro structures of carbon and graphite(石墨)remains influential in the scientific community. 展开更多
关键词 FRANKLIN SCATTERED PERFECT
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Fun in Alaska
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作者 Ruth Devlin 《空中英语教室(初级版.大家说英语)》 2024年第11期14-16,51,共4页
Visiting Alaska is a wonderful experience!It's the biggest state in the USA and has lots of exciting things to see and do.You can see amazing mountains and huge glaciers.Alaska is famous for its beautiful,wild ani... Visiting Alaska is a wonderful experience!It's the biggest state in the USA and has lots of exciting things to see and do.You can see amazing mountains and huge glaciers.Alaska is famous for its beautiful,wild animals.Many moose,several kinds of bear and other smaller animals make their homes there.You can hike,fish or go in a boat on a lake.Alaska has more than three million of them!You can also take a train trip.It's the perfect way to enjoy the beautiful Alaska scenery! 展开更多
关键词 BEAUTIFUL MOUNTAINS PERFECT
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Mammut:The brand's path to innovation
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《China Textile》 2024年第2期15-15,共1页
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
关键词 PERFECT LOOKING SMART
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Using Return and Risk Model for Choosing Perfect Portfolio Applied Study in Cairo Stock Exchange
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作者 Essam Al Arbed 《American Journal of Operations Research》 2024年第1期32-58,共27页
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
关键词 Game Theory Stochastic and Linear Programming Perfect Portfolio Portfolio Theory Returns and Risks
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The Absence of “Perfect Induction”in the Science
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作者 Corrado Giannantoni 《Journal of Applied Mathematics and Physics》 2024年第5期1930-1947,共18页
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
关键词 Perfect Induction Maximum Ordinality Principle Incipient Differential Calculus
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Practice Makes Perfect
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作者 乔文广 张超(指导) 《中学生英语》 2024年第22期7-7,共1页
All of us know the old saying“Practice makes perfect”.It tells us if we want to realize our goals,we should practice,and one day we will make it.Once I wanted to learn swimming.At first I found it difficult to contr... All of us know the old saying“Practice makes perfect”.It tells us if we want to realize our goals,we should practice,and one day we will make it.Once I wanted to learn swimming.At first I found it difficult to control my body.I just went down into the water.I felt very frightened.Then I watched others who were good at it and asked them the key to success. 展开更多
关键词 PERFECT PERFECT saying
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Whole Perfect Vectors and Fermat’s Last Theorem
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作者 Ramon Carbó-Dorca 《Journal of Applied Mathematics and Physics》 2024年第1期34-42,共9页
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
关键词 Fermat’s Last Theorem Whole Perfect Vectors Sine and Cosine Functions Natural and Rational Vectors Fermat Vectors
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Cooperative maneuver decision making for multi-UAV air combat based on incomplete information dynamic game 被引量:4
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作者 Zhi Ren Dong Zhang +2 位作者 Shuo Tang Wei Xiong Shu-heng Yang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第9期308-317,共10页
Cooperative autonomous air combat of multiple unmanned aerial vehicles(UAVs)is one of the main combat modes in future air warfare,which becomes even more complicated with highly changeable situation and uncertain info... Cooperative autonomous air combat of multiple unmanned aerial vehicles(UAVs)is one of the main combat modes in future air warfare,which becomes even more complicated with highly changeable situation and uncertain information of the opponents.As such,this paper presents a cooperative decision-making method based on incomplete information dynamic game to generate maneuver strategies for multiple UAVs in air combat.Firstly,a cooperative situation assessment model is presented to measure the overall combat situation.Secondly,an incomplete information dynamic game model is proposed to model the dynamic process of air combat,and a dynamic Bayesian network is designed to infer the tactical intention of the opponent.Then a reinforcement learning framework based on multiagent deep deterministic policy gradient is established to obtain the perfect Bayes-Nash equilibrium solution of the air combat game model.Finally,a series of simulations are conducted to verify the effectiveness of the proposed method,and the simulation results show effective synergies and cooperative tactics. 展开更多
关键词 Cooperative maneuver decision Air combat Incomplete information dynamic game Perfect bayes-nash equilibrium Reinforcement learning
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Reconfigurable metamaterial for asymmetric and symmetric elastic wave absorption based on exceptional point in resonant bandgap 被引量:3
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作者 Jianlin YI Zheng WU +1 位作者 Rongyu XIA Zheng LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第1期1-20,共20页
Elastic wave absorption at subwavelength scale is of significance in many engineering applications.Non-Hermitian metamaterials show the ability in high-efficiency wave absorption.However,the single functionality of me... Elastic wave absorption at subwavelength scale is of significance in many engineering applications.Non-Hermitian metamaterials show the ability in high-efficiency wave absorption.However,the single functionality of metamaterials is an important limitation on their practical applications for lack of tunability and reconfigurability.Here,we propose a tunable and reconfigurable non-Hermitian piezoelectric metamaterial bar,in which piezoelectric bars connect with resonant circuits,to achieve asymmetric unidirectional perfect absorption(UPA)and symmetric bidirectional perfect absorption(PA)at low frequencies.The two functions can be arbitrarily switched by rearranging shunted circuits.Based on the reverberation-ray matrix(RRM)method,an approach is provided to achieve UPA by setting an exceptional point(EP)in the coupled resonant bandgap.By using the transfer matrix method(TMM)and the finite element method(FEM),it is observed that a non-Hermitian pseudo-band forms between two resonant bandgaps,and the EP appears at the bottom of the pseudo-band.In addition,the genetic algorithm is used to accurately and efficiently design the shunted circuits for desired low-frequency UPA and PA.The present work may provide new strategies for vibration suppression and guided waves manipulation in wide potential applications. 展开更多
关键词 non-Hermitian metamaterial exceptional point(EP) unidirectional perfect absorption(UPA) piezoelectric metamaterial reverberation-ray matrix(RRM)method genetic algorithm
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High-temperature annealing of(201)β-Ga_(2)O_(3) substrates for reducing structural defects after diamond sawing
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作者 Pavel Butenko Michael Boiko +5 位作者 Mikhail Sharkov Aleksei Almaev Aleksnder Kitsay Vladimir Krymov Anton Zarichny Vladimir Nikolaev 《Journal of Semiconductors》 EI CAS CSCD 2023年第12期125-132,共8页
A commercial epi-ready(201)β-Ga_(2)O_(3) wafer was investigated upon diamond sawing into pieces measuring 2.5×3 mm^(2).The defect structure and crystallinity in the cut samples has been studied by X-ray diffract... A commercial epi-ready(201)β-Ga_(2)O_(3) wafer was investigated upon diamond sawing into pieces measuring 2.5×3 mm^(2).The defect structure and crystallinity in the cut samples has been studied by X-ray diffraction and a selective wet etching technique.The density of defects was estimated from the average value of etch pits calculated,including near-edge regions,and was obtained close to 109 cm^(-2).Blocks with lattice orientation deviated by angles of 1-3 arcmin,as well as non-stoichiometric fractions with a relative strain about(1.0-1.5)×10^(-4)in the[201]direction,were found.Crystal perfection was shown to decrease significantly towards the cutting lines of the samples.To reduce the number of structural defects and increase the crystal perfection of the samples via increasing defect motion mobility,the thermal annealing was employed.Polygonization and formation of a mosaic structure coupled with dislocation wall appearance upon 3 h of annealing at 1100℃ was observed.The fractions characterized by non-stoichiometry phases and the block deviation disappeared.The annealing for 11 h improved the homogeneity and perfection in the crystals.The average density of the etch pits dropped down significantly to 8×10^(6) cm^(-2). 展开更多
关键词 gallium oxide epi-ready substrate etch pits crystal defect mosaic structure crystal perfection
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A three-band perfect absorber based on a parallelogram metamaterial slab with monolayer MoS_(2)
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作者 张雯婧 刘青松 +3 位作者 程波 晁明豪 徐云 宋国峰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期280-285,共6页
As a two-dimensional(2D)material,monolayer MoS2which limits its optical applications has a low absorption efficiency.In this paper,we propose a three-band perfect metamaterial absorber in the visible light range based... As a two-dimensional(2D)material,monolayer MoS2which limits its optical applications has a low absorption efficiency.In this paper,we propose a three-band perfect metamaterial absorber in the visible light range based on monolayer MoS_(2).The peak absorptivity of the structure at each resonance wavelength is nearly perfect,moreover,the light absorption of monolayer MoS2is obviously enhanced at the three resonant wavelengths.The dielectric–dielectric–metal structure we designed produces the coupling of Fabry–Perot resonance and high-order diffraction guided-mode resonance at different absorption peaks,which has been proved by the slab waveguide theory.In addition,the multi-modal absorption phenomenon is explained by extracting the equivalent impedance.The results show that we can adjust the absorption peak wavelength by regulating the parameters of the structure.This structure not only provides an idea for enhancing the interaction between light and two-dimensional materials but also has potential applications for optical detection devices. 展开更多
关键词 METAMATERIAL perfect absorber monolayer MoS_(2) high-order diffraction
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