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THz-Wave Difference Frequency Generation by Phase-Matching in GaAs/Al_(x)Ga_(1-x)As Asymmetric Quantum Well

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Chinese Physics Letters 2012年第6期29卷 133-136页

作者： CAO Xiao-Long WANG Yu-Ye XU De-Gang ZHONG Kai LI Jing-Hui LI Zhong-Yang zhu neng-nian YAO Jian-Quan College of Precision Instrument and Opto-electronics Engineering Institute of Laser and Opto-electronicsTianjin UniversityTianjin 300072 Key Laboratory of Opto-electronics Information Technology(Ministry of Education) Tianjin UniversityTianjin 300072 Department of Computer Science and Technology Renai CollegeTianjin UniversityTianjin 301636

An asymmetric quantum well (AQW) is designed to emit a terahertz (THz) wave by using difference frequency generation (DFG) with the structure of GaAs/Al_(0.2)Ga_(0.8)As/Al_(0.5) Ga_(0.5)As under a doubly resonant *** is found that the second-order nonlinear susceptibility χ^((2)) varies with the two pump wavelengths,and it can reach the peak value of 1.61 μm/V when the wavelengths are given as λ_(p1) =9.756 μm and λ_(p2) =10.96 μm,*** numerical results show that the refractive index of one pump wave in the AQW is concerned with not only its own wavelength but also the other ***-matching inside the AQW can be obtained through the tuning of the two pump wavelengths.

关键词： pump tuning Phase

Profile of Dr. Jiaojun zhu

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Science China(Life Sciences) 2025年第2期68卷 311-313页

作者： zhu, Jiaojun

Dr. Jiaojun zhu is the director general of Institute of Applied Ecology(IAE), Chinese Academy of Sciences(CAS)(2018 to present). He received his B.S. degree in Forest Science from Shenyang Agricultural University, China in July 1987, and subsequently joined Institute of Forestry and Soil, CAS(now known as the IAECAS) to pursue his M.S. degree in *** graduation, he served as a research assistant and an associate research fellow in the IAE-CAS from 1990 to 1996.

关键词： Forest pursue assistant

Modification of Maxwell model for conductivity prediction of carbon nanotubes-filled polymer composites with tunneling effect

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 25-36页

作者： Jue zhu Longyuan LI Ningtao zhu Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline Key Laboratory of Impact and Safety Engineering (Ningbo University) Ministry of Education School of Engineering Computing and Mathematics University of Plymouth Xi'an Zhanshi Testing & Engineering Co.Ltd.

Carbon nanotubes(CNTs) have garnered great attention in recent years due to their outstanding electrical, thermal, and mechanical properties. The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity. This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect. In this modified Maxwell model, the CNTs-filled polymer composite is modeled as a three-phase composite, consisting of a matrix(polymer), inclusions(CNTs), and a transition zone(tunneling zone). The effective electrical conductivity(EEC) of the composite is calculated based on the volume fractions and electrical conductivities of the matrix, inclusions, and transition zone. The model's validity is confirmed through the use of available test data, which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites. This study offers valuable insights into the design of high-performance conductive polymer nanocomposites, and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.

关键词： carbon nanotube (CNT) composite electrical conductivity Maxwell model O242.2 O441.1 polymer tunneling

New insight into the origin and evolution of the flora and fauna of Hainan Island,China

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Science China Earth Sciences 2025年第1期68卷 52-61页

作者： Hua zhu Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesYunnan International Joint Laboratory of Southeast Asia Biodiversity ConservationYunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian ElephantsMengla666303China

The origin of the biota of Hainan Island,China,remains a fundamental scientific *** studies on the biota,geological tectonics,and paleomagnetism proposed that during the Eocene,Hainan Island connected Vietnam and Guangxi,and then moved to the southeast to reach its present *** review mainly discusses its biota origin from molecular phylogeny and palaeobotanical *** formation and evolution of the biological groups of Hainan Island were identified via research on their genomes,phylogeny,and molecular *** research showed that the genera and species that appeared and diverged early in their evolution(i.e.,before the Miocene)can be explained by the land connection between Hainan Island,Vietnam,and Guangxi during the *** to Southeast Asian tectonic theory,in the Middle Miocene(at about 15 million years ago),Hainan Island had moved to its present *** population and genetic divergence of species with late divergence times(after 15 Ma)can be reasonably explained by the close proximity(or land connection)between Hainan Island and the Leizhou Peninsula,enabling genetic communication between Hainan Island and the Chinese mainland,but have exceptional *** have been obtained through palaeobotanical studies,showing that in the Eocene-Oligocene period,southwest China and Hainan Island had subtropical vegetation and ***,the fossil group in southeast China(in Maoming,near present-day Hainan Island)in the Late Eocene indicated a tropical rainforest vegetation and *** suggests that in the Paleogene,Hainan Island may have been located near or on the southwest border of Guangxi and northern Vietnam,rather than in its present *** floristic division of the flora of Hainan Island basically presents a northeast-southwest inclined distribution *** pattern can be explained by the counterclockwise rotation of Hainan Island during its movement to the southeast as prop

关键词： Molecular phylogeny Biogeography Paleobotany Origin of flora and fauna Hainan Island of China

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Stabilities of delay stochastic McKean-Vlasov equations in the G-framework

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Science China(Information Sciences) 2025年第1期68卷 255-277页

作者： Haiyan YUAN Quanxin zhu Department of Mathematics Heilongjiang Institute of Technology Key Laboratory of Computing and Stochastic Mathematics (Ministry of Education) School of Mathematics and Statistics Hunan Normal University

This article focuses on a type of stochastic Mc Kean-Vlasov equation in the G-framework(G-SMVE) and addresses the stability issue for delay stochastic Mc Kean-Vlasov equations in the G-framework(G-SMVDEs). Distribution dependence and uncertainty prevent us from directly applying the stochastic analysis method for stochastic Mc Kean-Vlasov equations(SMVEs)to G-SMVEs directly. To overcome this difficulty, we introduce definitions, including the derivative of a function with a law under the G-expectation and the Lions derivatives. Then we construct a new G-It? formula for G-SMVEs according to the G-It? formula for stochastic differential equations in the G-framework(G-SDEs) and the It? formula for SMVEs. Using the new G-It? formula and the Lyapunov functional method, we investigate the moment exponential stability and almost sure asymptotic stability of G-SMVDEs. To overcome the difficulty in obtaining the distribution dependence of the exact solution to the G-SMVDE, we introduce the empirical measure and the corresponding interacting particle system, and then prove the stability equivalence between the underlying G-SMVDE and the corresponding interacting particle system. Two examples are used to confirm our theoretical results.

关键词： delay stochastic McKean-Vlasov equations Wasserstein distance G-Brownian motion Lions derivative stability

“Slope-adsorption&plateau-pore filling”mechanism unlocking the potential of hard carbon anodes for“fast-charging&large-sized”batteries

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Science China Materials 2025年第1期68卷 309-311页

作者： Tian Liang Xiaoming zhu Hubei Key Laboratory of Radiation Chemistry and Functional Materials School of Nuclear Technology and Chemistry&BiologyHubei University of Science and TechnologyXianning 437100China

To date,there has been no report on fast-charging and Ahlevel sodium-ion batteries(SIBs)by utilizing thick hard carbon anodes that demonstrate prolonged cycling life and high areal capacity at high ***,the relationship among the complex structure of hard carbon,storage mechanism,and fastcharging performance in alkali-metal ion batteries has been a subject of ongoing debate[1,2].

关键词： mechanism charging utilizing

Chemical weathering in Manas River Basin:Driven by sulfuric acid or carbonic acid?

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Acta Geochimica 2025年第1期44卷 59-85页

作者： Jiaxin Zhang Bingqi zhu Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingChina University of Chinese Academy of Sciences BeijingChina

Carbonic acid produced by the dissolution of atmospheric and soil CO_(2)in water is usually the most dominant catalyst for chemical weathering,but a sulfuric aciddriven phenomenon,different from usual,was found in the orogenic belt watersheds dominated by silicate *** study,rooted in comprehensive field investigations in the Manas River Basin(MRB)north of the Tianshan Mountains,delves into the mechanisms and impacts of sulfuric and carbonic acid as catalysts driving diff erent types of chemical weathering in the Central Asian Orogenic *** analyses elucidate that carbonate weathering constitutes 52.4%of the total chemical weathering,while silicate and evaporite account for 18.6%and 25.3%,respectively,with anthropogenic activities and atmospheric precipitation having little eff *** estimated total chemical weathering rate in MRB is approximately 0.075×10^(6)mol/km^(2)/*** findings further suggest that,preceding carbonate precipitation(<10^(4)year),chemical weathering can absorb CO_(2).Subsequently,and following carbonate precipitation(10^(4)-10^(7)year),it will release CO_(2).The release significantly surpasses the global average CO_(2)consumption,contributing to a noteworthy climate *** study underscores the distinctive weathering mechanisms,wherein sulfuric acid emerges as the predominant *** quantity of sulfuric acid as a catalyst is approximately three times that of carbonic *** acid-driven carbonate rock weathering(SCW)is identified as the sole chemical weathering type with a net CO_(2)release eff *** CO_(2)release flux(5176 mol/km^(2)/year)is roughly 2.5 times the CO_(2)absorption by Ca-Mg silicate weathering,highlighting the pivotal role of chemical weathering in sourcing atmospheric CO_(2)over the timescales of carbonate precipitation and sulfate ***,this study posits that catalyst and transport limitations are the most plausible critical factors in *** interplay between s

关键词： Catchment chemical weathering Mid-latitude orogenic belt Sulﬁde oxidation Manas River Basin

A water probe for direct pH measurement of individual particles via micro-Raman spectroscopy

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Journal of Environmental Sciences 2025年第3期149卷 200-208页

作者： Xiaoyu Cui Mingjin Tang Tong zhu School of Environmental Science and Engineering Tianjin UniversityTianjin 300072China BIC-ESAT and SKL-ESPC College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human *** recently developed a novel and facilewater-probebased method for directly measuring of the pH for micrometer-size droplets,providing a promising technique to better understand aerosol acidity in the *** complex chemical composition of fine particles in the ambient air,however,poses certain challenges to using a water-probe for pH measurement,including interference from interactions between compositions and the influence of similar compositions on water *** explore the universality of our method,it was employed to measure the pH of ammonium,nitrate,carbonate,sulfate,and chloride *** pH of particles covering a broad range(0–14)were accurately determined,thereby demonstrating that our method can be generally applied,even to alkaline ***,a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the *** library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar *** the spectral library,all ions were identified and their concentrations were determined,in turn allowing successful pH measurement of multicomponent(ammonium-sulfate-nitrate-chloride)*** into the synergistic effect of Cl^(–),NO_(3)^(–),and NH_(4)^(+)depletion obtained with our approach revealed the interplay between pH and volatile *** the ubiquity of component partitioning and pH variation in particles,the water probemay provide a new perspective on the underlying mechanisms of aerosol aging and aerosol–cloud interaction.

关键词： Particle pH Water probe Standard spectral library Micro-Raman spectroscopy Direct measurement

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基于非对称量子阱的太赫兹波调制器

激光与红外 2010年第8期40卷 896-900页

作者：朱能念姚建铨徐小燕李忠洋邴丕彬徐德刚光信息技术科学教育部重点实验室天津大学精仪学院激光与光电子研究所天津300072

主要研究了一个特殊的GaAs/AlGaAs非对称量子阱中的线性和三阶非线性太赫兹波吸收系数和介质折射率的相对改变。首先利用量子力学中的密度矩阵算符理论和迭代方法导出了线性和三阶非线性光吸收系数和相对折射率改变的表达式,然后以典型... 详细信息

主要研究了一个特殊的GaAs/AlGaAs非对称量子阱中的线性和三阶非线性太赫兹波吸收系数和介质折射率的相对改变。首先利用量子力学中的密度矩阵算符理论和迭代方法导出了线性和三阶非线性光吸收系数和相对折射率改变的表达式,然后以典型的阶梯型量子阱材料为例做了数值计算。计算表明,基于泵浦光场和偏置电压控制的太赫兹波调制器不仅可以做太赫兹波开关,还可以灵活地调制太赫兹波信号的强度和相位,方便实用。

关键词：量子阱太赫兹波调制器非线性光学