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《荀子》文本生成论 预览
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作者 郭强 张洪兴 《哈尔滨工业大学学报:社会科学版》 CSSCI 北大核心 2020年第1期76-82,共7页
对于先秦典籍而言,文本的生成是一个复杂的过程。主体层面上,《荀子》经过初始作者、辑录者、定本者三种角色的努力最终使得文本趋于定型,这显现了先秦子书从创作到定本的复杂性与历时性;文本构建层面上,《荀子》是对传统的重复以及在... 对于先秦典籍而言,文本的生成是一个复杂的过程。主体层面上,《荀子》经过初始作者、辑录者、定本者三种角色的努力最终使得文本趋于定型,这显现了先秦子书从创作到定本的复杂性与历时性;文本构建层面上,《荀子》是对传统的重复以及在传统基础上的衍变。传统的重复主要体现在文本书写的述古鉴今、前人篇章的效仿和公共材料的重复运用;传统基础上的衍变具有情境的转变、寓言的简洁化和对话人的消解等特点。重复与衍变揭橥了文本的规范性与流动性。 展开更多
关键词 《荀子》 文本 生成
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Rapid generation advance (RGA) in chickpea to produce up to seven generations per year and enable speed breeding 预览
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作者 Srinivasan Samineni Madhuparni Sen +1 位作者 Sobhan BSajja Pooran MGaura 《作物学报:英文版》 CAS CSCD 2020年第1期164-169,共6页
This study was aimed at developing a protocol for increasing the number of generation cycles per year in chickpea(Cicer arietinum L.).Six accessions,two each from early(JG 11 and JG 14),medium(ICCV 10 and JG 16),and l... This study was aimed at developing a protocol for increasing the number of generation cycles per year in chickpea(Cicer arietinum L.).Six accessions,two each from early(JG 11 and JG 14),medium(ICCV 10 and JG 16),and late(CDC-Frontier and C 235)maturity groups,were used.The experiment was conducted for two years under glasshouse conditions.The photoperiod was extended to induce early flowering and immature seeds were germinated to further reduce generation cycle time.Compared to control,artificial light caused a reduction in flowering time by respectively 8–19,7–16,and 11–27 days in early-,medium-,and late-maturing accessions.The earliest stage of immature seed able to germinate was 20–23 days after anthesis in accessions of different maturity groups.The time period between germination and the earliest stage of immature seed suitable for germination was considered one generation cycle and spanned respectively 43–60,44–64,and 52–79 days in early-,medium-,and late-maturing accessions.However,the late-maturing accession CDCFrontier could not be advanced further after three generation cycles owing to the strong influence of photoperiod and temperature.The mean total number of generations produced per year were respectively 7,6.2,and 6 in early-,medium-,and late-maturing accessions.These results have encouraging implications for breeding programs:rapid progression toward homozygosity,development of mapping populations,and reduction in time,space and resources in cultivar development(speed breeding). 展开更多
关键词 PHOTOPERIOD Immature seeds Flowering Rapid generation turnover Speed breeding
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基于C-R神经网络的生成式自动摘要方法 预览
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作者 王玮 《计算机与数字工程》 2020年第1期112-118,共7页
方法王玮(军事科学院研究生院北京100091)摘要文本自动摘要是一种利用计算机自动生成文本摘要的理论方法和技术。论文在对生成式自动摘要方法综述的基础上,提出了基于CNN和RNN混合神经网络的生成式自动摘要方法,对方法的思路进行了描述... 方法王玮(军事科学院研究生院北京100091)摘要文本自动摘要是一种利用计算机自动生成文本摘要的理论方法和技术。论文在对生成式自动摘要方法综述的基础上,提出了基于CNN和RNN混合神经网络的生成式自动摘要方法,对方法的思路进行了描述,并对原有方法和改进方法进行对比实验。实验结果表明,改进方法有更好的文本摘要生成效果。 展开更多
关键词 CNN RNN 生成式 自动摘要
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Modelling two-layer nanofluid flow in a micro-channel with electro-osmotic effects by means of Buongiorno’s model 预览
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作者 M.D.K.NIAZI Hang XU 《应用数学和力学:英文版》 SCIE EI CSCD 2020年第1期83-104,共22页
A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic effects.Buongiorno’s model is employed for describing the behavior of nanofluids.Differe... A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic effects.Buongiorno’s model is employed for describing the behavior of nanofluids.Different from the previous studies on two-layer channel flow of a nanofluid,the present paper introduces the flux conservation conditions for the nanoparticle volume fraction field,which makes this work new and unique,and it is in coincidence with practical observations.The governing equations are reduced into a group of ordinary differential equations via appropriate similarity transformations.The highly accurate analytical approximations are obtained.Important physical quantities and total entropy generation are analyzed and discussed.A comparison is made to determine the significance of electrical double layer(EDL)effects in the presence of an external electric field.It is found that the Brownian diffusion,the thermophoresis diffusion,and the viscosity have significant effects on altering the flow behaviors. 展开更多
关键词 electrical double layer(EDL) entropy generation MICRO-CHANNEL NANOFLUID
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Will Germany move into a situation with unsecured power supply?
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作者 Harald SCHWARZ 《能源前沿:英文版》 CSCD 2019年第3期551-570,共20页
Together with a huge number of other countries, Germany signed the Paris Agreements in 2015 to prevent global temperature increase above 2℃. Within this agreement, all countries defined their own national contributio... Together with a huge number of other countries, Germany signed the Paris Agreements in 2015 to prevent global temperature increase above 2℃. Within this agreement, all countries defined their own national contributions to CO2 reduction. Since that, it was visible that CO2 emissions in Germany decreased, but not so fast than proposed in this German nationally determined contribution to the Paris Agreement. Due to increasing traffic, CO2 emissions from this mobility sector increased and CO2 emission from German power generation is nearly constant for the past 20 years, even a renewable generation capacity of 112 GW was built up in 2017, which is much higher than the peak load of 84 GW in Germany. That is why the German National Government has implemented a commission (often called "The German Coal Commission") to propose a time line: how Germany can move out of coal-fired power stations. This "Coal Commission" started its work in the late spring of 2018 and handed over its final report with 336 pages to the government on January 26th, 2019. Within this report the following proposals were made:①Until 2022: Due to a former decision of the German Government, the actual remaining nuclear power generation capacity of about 10 GW has to be switched off in 2022. Besides, the "Coal Commission" proposed to switch off additionally in total 12.5 GW of both, hard coal and lignite-fired power plants, so that Germany should reduce its conventional generation capacity by 22.5 GW in 2022.②Until 2030: Another 13 GW of German hard coal or lignite-fired power plants should be switched off.③Until 2038:The final 17 GW of German hard coal or lignitefired power plants should be switched off until 2038 latest. Unfortunately the "Coal Commission" has not investigated the relevant technical parameter to ensure a secured electric power supply, based on German's own national resources. Because German Energy Revolution mainly is based on wind energy and photovoltaic, this paper will describe the negligible contribution of these sources 展开更多
关键词 CO2 reduction mobility sector RENEWABLE GENERATION coal COMMISSION secured POWER GENERATION capacity reliable POWER supply power-to-gas power-to-heat
Influence of intraband motion on the interband excitation and high harmonic generation
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作者 左瑞欣 宋晓红 +2 位作者 刘希望 杨士栋 杨玮枫 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第9期9-15,共7页
Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor st... Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor structure makes three steps become interatomic coherent process which leads to complicated carrier dynamics and two sources of high harmonic emission: interband polarization and intraband current.The difference of features of high harmonic generation between semiconductors and atoms is strongly linked to the unique presence of intraband motion which manifests itself a nontrivial role in intertwined two dynamics.Here, we review recent experimental and theoretical advances of understanding coupled interband and intraband mechanisms of HHG in semiconductors.Particularly we focus on the influence of intraband motion on the interband excitation, and on the subsequent HHG emission and attosecond pulse generation. 展开更多
关键词 high HARMONIC GENERATION interband POLARIZATION intraband current ATTOSECOND PULSE GENERATION
从“微本体”看系统的生成与消亡
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作者 苗东升 《系统科学学报》 CSSCI 北大核心 2019年第4期1-6,28,共7页
作为中国传统文化的概念,微反映的是一种四维存在:量-质维,几-必维,卑-尊维,隐-显维。本文分别按照这四个维度阐释微的含义,提出微世界和微意识概念,对"有生于微"命题作了补充论述,提出"亡始于微"命题,阐明它是系... 作为中国传统文化的概念,微反映的是一种四维存在:量-质维,几-必维,卑-尊维,隐-显维。本文分别按照这四个维度阐释微的含义,提出微世界和微意识概念,对"有生于微"命题作了补充论述,提出"亡始于微"命题,阐明它是系统消亡论的基本原理。 展开更多
关键词 系统(system) 微(wui or mite orε) 生成(generation) 消亡(dying)
Analysis of third and one-third harmonic generation in lossy waveguides
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作者 张剑宇 孙云旭 宋清海 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期209-212,共4页
A comprehensive study on the requirements for the highly efficient third harmonic generation(THG) and its inverse process, one-third harmonic generation(OTHG), in lossy waveguides is proposed. The field intensity rest... A comprehensive study on the requirements for the highly efficient third harmonic generation(THG) and its inverse process, one-third harmonic generation(OTHG), in lossy waveguides is proposed. The field intensity restrictions for both THG and OTHG caused by loss are demonstrated. The effective relative phase ranges, supporting the positive growth of signal fields of THG and OTHG are shrunken by the loss. Furthermore, it turns out that the effective relative phase ranges depend on the intensities of the interacting fields. At last, a modified definition of coherent length in loss situation, which evaluates the phase matching degree more precisely, is proposed by incorporating the shrunken relative phase range and the nonlinear phase mismatch. These theoretical analysis are valuable for guiding the experimental designs for highly efficient THG and OTHG. 展开更多
关键词 coupled mode theory THIRD HARMONIC GENERATION one-third HARMONIC GENERATION LOSS effects
营卫析解及临床应用研究 预览
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作者 侯仙明 刘淑彦 +3 位作者 潘永梅 方敬 贾云芳 贾春生 《河北中医药学报》 2019年第2期9-13,39共6页
笔者对营卫的生成、分布与循行提出了一些新的认识:⑴明确了营气与卫气的生成源头及组成。即营气之源头在中焦脾胃,其组成包括:水谷之精气和自然之清气;卫气之源头在下焦肾,其组成包括:水谷之精气、自然之清气和肾中之精气。⑵明确提出... 笔者对营卫的生成、分布与循行提出了一些新的认识:⑴明确了营气与卫气的生成源头及组成。即营气之源头在中焦脾胃,其组成包括:水谷之精气和自然之清气;卫气之源头在下焦肾,其组成包括:水谷之精气、自然之清气和肾中之精气。⑵明确提出营气循行有两条路线,分别为经络路线与血脉路线。⑶以取象比类的方法对卫气循行的3种方式进行了分析,提出了卫气有2种运行状态,其一为全身散布,由内而外的运行状态;其二为循经运行,昼行于阳,夜行于阴,一日一夜五十周于身的运行模式。⑷以太极阴阳消长变化模型对卫气“昼行于阳,夜行于阴”进行了重新解读。⑸对于卫气昼行于阳的路线提出主干与分支说,其循行主干是:起于目,沿太阳膀胱经之主干下行至足小趾,然后由小趾入足心,上内踝,走跷脉上行复归于目。主要涉及足太阳膀胱经、足少阴肾经(一部分)与跷脉。其他循行的阳经均是分支。⑹提出卫气的循行方向存在多向性。另外,除了理论上的认识外,本文还对“避”“脉”“随”等相关文字对内经原文中的含义进行了重新解读。 展开更多
关键词 营卫 营气 卫气 生成 分布 循行
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Dark matter and LHC phenomenology of a scale-invariant scotogenic model
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作者 郭超 郭书源 廖益 《中国物理C:英文版》 SCIE CAS CSCD 2019年第10期14-23,共10页
We study the phenomenology of a model that addresses the neutrino mass, dark matter, and generation of the electroweak scale in a single framework. Electroweak symmetry breaking is realized via the Coleman-Weinberg me... We study the phenomenology of a model that addresses the neutrino mass, dark matter, and generation of the electroweak scale in a single framework. Electroweak symmetry breaking is realized via the Coleman-Weinberg mechanism in a classically scale invariant theory, while the neutrino mass is generated radiatively through interactions with dark matter in a typically scotogenic manner. The model introduces a scalar triplet and singlet and a vector-like fermion doublet that carry an odd parity of Z2, and an even parity scalar singlet that helps preserve classical scale invariance. We sample over the parameter space by taking into account various experimental constraints from the dark matter relic density and direct detection, direct scalar searches, neutrino mass, and charged lepton flavor violating decays. We then examine by detailed simulations possible signatures at the LHC to find some benchmark points of the free parameters. We find that the future high-luminosity LHC will have a significant potential in detecting new physics signals in the dilepton channel. 展开更多
关键词 COLLIDER PHENOMENOLOGY NEUTRINO mass generation dark matter particle classical SCALE INVARIANCE
预设与生成:充满生命活力高校课堂教学的探索 预览
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作者 薛娟 《黑龙江高教研究》 北大核心 2019年第12期157-160,共4页
高校课堂教学的"沉默"和"单声道"现象促使我们反思,是否有完整的预设作为支撑,是否有观看"表演"的"观众",是否有以学生学为中心的预设。课堂教学是生命个体不断生成的活动,课程内容是师生不断... 高校课堂教学的"沉默"和"单声道"现象促使我们反思,是否有完整的预设作为支撑,是否有观看"表演"的"观众",是否有以学生学为中心的预设。课堂教学是生命个体不断生成的活动,课程内容是师生不断建构体验的课程,课堂教学是师生共同在场互动的过程,因此,需要回归以大学生的学习为重心的预设,回归以师生共生共长为目标的生成,构建师生学习共同体焕发课堂生命活力,促进教师更好地完成新时代的教育使命。 展开更多
关键词 预设 生成 高校课堂教学 生命活力
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SLIPS-TENG:robust triboelectric nanogenerator with optical and charge transparency using a slippery interface
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作者 Wanghuai Xu Xiaofeng Zhou +8 位作者 Chonglei Hao Huanxi Zheng Yuan Liu Xiantong Yan Zhengbao Yang Michael Leung Xiao Cheng Zeng Ronald X. Xu Zuankai Wang 《国家科学评论:英文版》 CSCD 2019年第3期540-550,共11页
Energy harvesting devices that prosper in harsh environments are highly demanded in a wide range of applications ranging from wearable and biomedical devices to self-powered and intelligent systems.Particularly,over t... Energy harvesting devices that prosper in harsh environments are highly demanded in a wide range of applications ranging from wearable and biomedical devices to self-powered and intelligent systems.Particularly,over the past several years,the innovation of triboelectric nanogenerators(TENGs)that efficiently convert ambient kinetic energy of water droplets or wave power to electricity has received growing attention.One of the main bottlenecks for the practical implications of such devices originates from the fast degradation of the physiochemical properties of interfacial materials under harsh environments.To overcome these challenges,here we report the design of a novel slippery lubricant-impregnated porous surface(SLIPS)based TENG,referred to as SLIPS-TENG,which exhibits many distinctive advantages over conventional design including optical transparency,configurability,self-cleaning,flexibility,and power generation stability,in a wide range of working environments.Unexpectedly,the slippery and configurable lubricant layer not only serves as a unique substrate for liquid/droplet transport and optical transmission,but also for efficient charge transfer.Moreover,we show that there exists a critical thickness in the liquid layer,below which the triboelectric effect is almost identical to that without the presence of such a liquid film.Such an intriguing charge transparency behavior is reminiscent of the wetting transparency and van der Waals potential transparency of graphene previously reported,though the fundamental mechanism remains to be elucidated.We envision that the marriage of these two seemingly totally different arenas(SLIPS and TENG)provides a paradigm shift in the design of robust and versatile energy devices that can be used as a clean and longer-lifetime alternative in various working environments. 展开更多
关键词 slippery surface triboelectricity power generation water DROPLET interfaces
Full vectorial feature of second-harmonic generation with full Poincaré beams
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作者 张莉 林飞 +1 位作者 邱晓东 陈理想 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第9期78-82,共5页
We demonstrate the full vectorial feature of second-harmonic generation(SHG), i.e., from infrared full Poincaré beams to visible full Poincaré beams, based on two cascading type I phase-matching beta barium ... We demonstrate the full vectorial feature of second-harmonic generation(SHG), i.e., from infrared full Poincaré beams to visible full Poincaré beams, based on two cascading type I phase-matching beta barium borate crystals of orthogonal optical axes. We visualize the structured features of the vectorial SHG wave by using Stokes polarimetry and show the interesting doubling effect of the polarization topological index, i.e., a low-order full Poincaré beam is converted to a high-order one. However, the polarization singularities of both C points and L lines are found to keep invariant during the SHG process. Our scheme could offer a deeper understanding on the interaction of vectorial light fields with media and can be generalized to other nonlinear optical effects. 展开更多
关键词 Full vectorial FEATURE second-harmonic GENERATION full POINCARE BEAMS
Generate basic conceptual solutions for 3DPVS via utilizing TRIZ 预览
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作者 Haobo Yuan Ke Xing Hung-Yao Hsu 《生物设计与制造(英文)》 CSCD 2019年第2期76-95,共20页
For cell culture scaffold innovation,3DPVS,namely 3D printed vibratory scaffold,was indicated as a future novel product,and it currently stands at conceptual development stage.One essential part for 3DPVS design is in... For cell culture scaffold innovation,3DPVS,namely 3D printed vibratory scaffold,was indicated as a future novel product,and it currently stands at conceptual development stage.One essential part for 3DPVS design is innovation,and TRIZ(algorithm of inventive problem solving)was studied as promising method for generating novel conceptual solutions.This study targets designing and solving 3DPVS problems using TRIZ in the new biodimension.We aim to utilize TRIZ to conduct a multi-layer problem-solving process,which is to address design concerns of 3DPVS,especially at super-system to system level.In this connection,TRIZ is used to address basic constraints and contradictions inside regarding trinity of 3D printing,3D scaffold and bio-based vibratory functionality.In the study,five basic conceptual solutions for potential 3DPVS,namely magnetic,electric,mechanical,light and thermal based,have been generated.A brief evaluation has also been conducted,where magnetic-based 3DPVS shows the relatively highest applicability as potential 3DPVS.Compared with traditional experimental-oriented processes for biodesign,the approach of utilizing TRIZ can be inspiring and reinvigorating,which prepares a ground for future 3DPVS design to address detailed sub-system concerns.This study might,to some extent,fill a gap in scaffold design and TRIZ literature and hopefully provide a comprehensive perspective of a timely topic. 展开更多
关键词 3DPVS 3D SCAFFOLD 3D PRINTING SCAFFOLD INNOVATION Biodesign TRIZ CONCEPT generation
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The revival of thermal utilization from the Sun:interfacial solar vapor generation
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作者 Lin Zhou Xiuqiang Li +2 位作者 George W. Ni Shining Zhu Jia Zhu 《国家科学评论:英文版》 CSCD 2019年第3期562-578,共17页
Since solar energy is the ultimate energy resource and a significant amount of global energy utilization goes through heat,there have been persistent efforts for centuries to develop devices and systems for solar–the... Since solar energy is the ultimate energy resource and a significant amount of global energy utilization goes through heat,there have been persistent efforts for centuries to develop devices and systems for solar–thermal conversion.Most recently,interfacial solar vapor generation,as an emerging concept of solar–thermal conversion,has gained significant attention for its great potentials in various fields such as desalination,sterilization,catalysis,etc.With the advances of rationally designed materials and structures and photon and thermal management at the nanoscale,interfacial solar vapor generation has demonstrated both thermodynamic and kinetical advantages over conventional strategies.In this review,we aim to illustrate the definition,mechanism and figures of merit of interfacial solar vapor generation,and to summarize the development progress of relevant materials and applications,as well as to provide a prospective view of the future. 展开更多
关键词 SOLAR vapor generation SOLAR ABSORBER SOLAR EVAPORATOR INTERFACIAL heating
Obstacle Avoidance Method for a Redundant Manipulator Based on a Configuration Plane 预览
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作者 Yanhui Wei Yanfeng Zhao +4 位作者 Jing Liu Shenggong Hao Lixue Xu Qiang Zhu Anqi Wang 《北京理工大学学报:英文版》 EI CAS 2019年第3期456-468,共13页
This paper presents a novel approach of obstacle avoidance for redundant manipulators, which is challenging with the considerations of the building of universal kinematics, the formation of dynamics, and the generatio... This paper presents a novel approach of obstacle avoidance for redundant manipulators, which is challenging with the considerations of the building of universal kinematics, the formation of dynamics, and the generation of trajectories. A universal approach to deal with obstacle avoidance for the redundant manipulator, that is based on the configuration plane, is presented. The paper also examines common serial robot configurations and introduces a method for classification, partitioning, simplification, and forms of expression used in the workspace to define the configuration plane. This relatively new method is combined with a weighted space vector method to match the configuration plane and solve the inverse kinematics problem. The proposed planner is demonstrated with examples, in which the proposed planner is shown to be capable of providing a smoother trajectory. 展开更多
关键词 REDUNDANT manipulator CONFIGURATION PLANE trajectory generation OBSTACLE AVOIDANCE space vector
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Nonlinear optics in the electron-hole continuum in 2D semiconductors:two-photon transition, second harmonic generation and valley current injection
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作者 Pu Gong Hongyi Yu +1 位作者 Yong Wang Wang Yao 《科学通报:英文版》 SCIE EI CSCD 2019年第15期1036-1043,共8页
We investigate two-photon transitions to the electron-hole scattering continuum in monolayer transition-metal dichalcogenides, and identify two contributions to this nonlinear optical process with opposite circularly ... We investigate two-photon transitions to the electron-hole scattering continuum in monolayer transition-metal dichalcogenides, and identify two contributions to this nonlinear optical process with opposite circularly polarized valley selection rules. In the non-interacting limit, the competition between the two contributions leads to a crossover of the selection rule with the increase of the two-photon energy. With the strong Coulomb interaction between the electron and hole, the two contributions excite electron-hole scattering states in orthogonal angular momentum channels, while the strength of the transition can be substantially enhanced by the interaction. Based on this picture of the two-photon transition, the second harmonic generation(SHG) in the electron-hole continuum is analyzed, where the Coulomb interaction is shown to greatly alter the relative strength of different cross-circular polarized SHG processes. Valley current injection by the quantum interference of one-photon and two-photon transition is also investigated in the presence of the strong Coulomb interaction, which significantly enhances the injection rate. 展开更多
关键词 2D SEMICONDUCTORS Nonlinear optics Electron-hole CONTINUUM Two-photon transition Second-harmonic generation VALLEY current injection
长白公猪不同代数及血缘对产活仔数和初生重的影响 预览 被引量:1
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作者 潘建文 《福建畜牧兽医》 2019年第4期15-17,共3页
本文通过收集福建某猪场2015-2018年长白猪的生产数据,研究公猪代数、血缘对母猪产活仔数、仔猪初生重的影响。结果表明:长白猪不同代数对产活仔数与初生重有显著差异,产活仔数第3代最多,为12.34头。初生重第2、第3代最高,代数1至代数2... 本文通过收集福建某猪场2015-2018年长白猪的生产数据,研究公猪代数、血缘对母猪产活仔数、仔猪初生重的影响。结果表明:长白猪不同代数对产活仔数与初生重有显著差异,产活仔数第3代最多,为12.34头。初生重第2、第3代最高,代数1至代数2的初生重呈上升趋势,代数3、代数4呈下降趋势,表明选择第3代最好;血缘关系对产活仔数呈现差异性,其中血缘2最多(12.24头),相比其他血缘有很高的优越性。血缘对于初生重也有很大差异影响,血缘23与血缘2、15、17有显著差异性。 展开更多
关键词 代数 血缘 产活仔数 初生重
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Facile oxalic acid-assisted construction of laminated porous N-deficient graphitic carbon nit ride: Highly efficient visible-light-driven hydrogen evolution photocatalyst 预览
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作者 Fengli Yang Jia Ren +3 位作者 Qianqian Liu Lu Zhang Yuanyuan Chai Wei-Lin Dai 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第6期1-8,共8页
The laminated porous N-deficient g-C3N4(CN–H)is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the precursor.Compared with pristine g-C3N4(224μmo... The laminated porous N-deficient g-C3N4(CN–H)is successfully synthesized by a facile two-step hydrothermal calcination method using oxalic acid-assisted melamine as the precursor.Compared with pristine g-C3N4(224μmol g-1h-1),the CN–H shows superior photocatalytic hydrogen production activity(up to 728μmol g-1h-1),which is three times higher than the unmodified counterpart.To draw out the multifaceted influences of oxalic acid modification on the visible-light-induced photocatalytic activity,various techniques are utilized to investigate the formation mechanism,structural characteristics and photoelectrical properties of CN–H.The results indicate that the addition of a trace amount of oxalic acid to the precursor melamine results in a g-C3N4 structure possessing the advantage of both nitrogen defects and laminated porosity.These properties can enlarge specific surface areas of g-C3N4,enhance an efficient separating of photogenerated electron-hole pairs and extend the range of spectral response,all contributing to the enhancement of the visible-light-induced photocatalytic activity. 展开更多
关键词 Oxalic acid MELAMINE LAMINATED POROUS N-deficient g-C3N4 Visible-light-induced photocatalytic activity for H2 generation
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Exergetic sustainability evaluation and optimization of an irreversible Brayton cycle performance
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作者 Mohammad H. AHMADI Mohammad-Ali AHMADI +3 位作者 Esmaeil ABOUKAZEMPOUR Lavinia GROSU Fathollah POURFAYAZ Mokhtar BIDI 《能源前沿:英文版》 CSCD 2019年第2期399-410,共12页
Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of op... Owing to the energy demands and global warming issue, employing more effective power cycles has become a responsibility. This paper presents a thermo-dynamical study of an irreversible Brayton cycle with the aim of optimizing the performance of the Brayton cycle. Moreover, four different schemes in the process of multi-objective optimization were suggested, and the outcomes of each scheme are assessed separately. The power output, the concepts of entropy generation, the energy, the exergy output, and the exergy efficiencies for the irreversible Brayton cycle are considered in the analysis. In the first scheme, in order to maximize the exergy output, the ecological function and the ecological coefficient of performance, a multi-objective optimization algorithm (MOEA) is used. In the second scheme, three objective functions including the exergetic performance criteria, the ecological coefficient of performance, and the ecological function are maximized at the same time by employing MOEA. In the third scenario, in order to maximize the exergy output, the exergetic performance criteria and the ecological coefficient of performance, a MOEA is performed. In the last scheme, three objective functions containing the exergetic performance criteria, the ecologi-cal coefficient of performance, and the exergy-based ecological function are maximized at the same time by employing multi-objective optimization algorithms. All the strategies are implemented via multi-objective evolu-tionary algorithms based on the NSGAII method. Finally, to govern the final outcome in each scheme, three well- known decision makers were employed. 展开更多
关键词 ENTROPY generation EXERGY Brayton CYCLE ECOLOGICAL function IRREVERSIBILITY
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