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Origin of Luminescent Centers and Edge states in Low-Dimensional Lead Halide Perovskites:Controversies,Challenges and Instructive Approaches

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Nano-Micro Letters 2019年第2期11卷 109-126页

作者： Jiming Bao Viktor G.Hadjiev Department of Electrical and Computer Engineering University of HoustonHoustonTX 77204USA Department of Chemistry University of HoustonHoustonTX 77204USA Materials Science and Engineering University of HoustonHoustonTX 77204USA Texas Center for Superconductivity University of HoustonHoustonTX 77204USA Department of Mechanical Engineering University of HoustonHoustonTX 77204USA

With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency,low-cost,solar cells and light-emitting devices.As such,recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates.The observed green emission in 2D CsPb2Br5 and 0 D Cs4PbBr6 poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr3 nanocrystals embedded in the otherwise transparent wide band gap semiconductors.The nature of deep-level edge emission in 2D Ruddlesden–Popper perovskites is also not well understood.In this mini review,the experimental evidences that support the opposing interpretations are analyzed,and challenges and root causes forthe controversy are discussed.Shortcomings in the current density functional theory approaches to modeling of properties and intrinsic point defects in lead halide perovskites are also noted.Selected experimental approaches are suggested to better correlate property with structure of a material and help resolve the controversies.Understanding and identification of the origin of luminescent centers will help design and engineer perovskites for wide device applications.

关键词： Low-dimensional perovskites Luminescent centers Edge states Cesium lead halides Deep-level states Ruddlesden–Popper perovskites

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Data-driven models for ground and excited states for Single Atoms on Ceria

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npj Computational Materials 2022年第1期8卷 1636-1643页

作者： Julian Geiger Albert Sabadell-Rendón Nathan Daelman Núria López Institute of Chemical Research of Catalonia(ICIQ) The Barcelona Institute of Science and Technology(BIST)Avinguda Països Catalans 1643007TarragonaSpain Universitat Rovira i Virgili Avinguda Catalunya3543002TarragonaSpain

Ceria-based single-atom catalysts present complex electronic structures due to the dynamic electron transfer between the metal atoms and the semiconductor oxide support.Understanding these materials implies retrieving all states in these electronic ensembles,which can be limiting if done via density functional theory.Here,we propose a data-driven approach to obtain a parsimonious model identifying the appearance of dynamic charge transfer for the single atoms(SAs).We first constructed a database of(701)electronic configurations for the group 9–11 metals on CeO_(2)(100).Feature Selection based on predictive Elastic Net and Random Forest models highlights eight fundamental variables:atomic number,ionization potential,size,and metal coordination,metal–oxygen bond strengths,surface strain,and Coulomb interactions.With these variables a Bayesian algorithm yields an expression for the adsorption energies of SAs in ground and low-lying excited states.Our work paves the way towards understanding electronic structure complexity in metal/oxide interfaces.

关键词： theory excited states

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Effects of a Λ hyperon on the negative-parity states of ^(20)Ne

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Science China(Physics,Mechanics & Astronomy) 2023年第5期66卷 207-207页

作者： Ji-Wei Cui Xian-Rong Zhou School of Physics Xidian UniversityXi’an 710071China Department of Physics East China Normal UniversityShanghai 200241China

The properties of the clusterized structure in ^(21)_(Λ)Ne are stud-ied in detail based on a beyond relativistic mean-field(RMF)model in a recent paper[1],“The interplay of single-particle and collective motions in the low-lying states of ^(21)_(Λ)Ne with quadrupole-octupole correlations”.The intrinsic mean-field states of ^(21)_(Λ)Ne with quadrupole and octupole constraints are projected on certain angular momenta and parities,and the generator coordinate method is used to simultaneously consider configurational mixing.

关键词： states parity collective

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Modeling Impact of Natural Hazard-Induced Disasters on Income Distribution in the United states

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International Journal of Disaster Risk Science 2017年第4期8卷 435-444页

作者： Lin Fang Jiayu Wu Tatjana Miljkovic Department of Statistics Miami UniversityOxfordOH 45056USA

Economic damage due to hurricane activities has been shown to impact income inequality in the coastal states of the United states. We consider 17 other natural hazards, in addition to hurricanes, that affected the entire United states for the period 1970–2013. Two fixed effects models were developed to quantify the relationship between income inequality and economic and demographic variables, including crop and property losses from natural hazard-induced disasters. These models include state-byyear and region-by-year fixed effects models. Our findings show that the damages from all natural hazards impact income distribution across the United states, not only in hurricane-affected areas, but also in non-hurricane states.The results of our study have important implications for the insurance industry and government policymakers.

关键词： Disaster insurance Gini coefficient Income distribution Natural hazard-induced disasters United states

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Consensus on management of hepatitis C virus infection in resource-limited Ukraine and Commonwealth of Independent states regions

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World Journal of Gastroenterology 2019年第29期25卷 3897-3919页

作者： Massimo Giuseppe Colombo Erkin Isakovich Musabaev Umed Yusupovich Ismailov Igor A Zaytsev Alexander V Nersesov Igor Anatoliyevich Anastasiy Igor Alexandrovich Karpov Olga A Golubovska Kulpash S Kaliaskarova Ravishankar AC Sanjay Hadigal Research and Clinical Center Department of Medicine Humanitas Hospital Rozzano 20089 MI Italy Research Institute of Virology Scientific Research Institute of Virology Tashkent 100194 Uzbekistan Hepatoсenter Research Institute of Virology Scientific Research Institute of Virology Tashkent 100194 Uzbekistan Department of Therapy Infectious Diseases and Dermatology Bogomolets National Medical University Kyiv 01601 Ukraine Department of Gastroenterology and Hepatology National Research Institute of Cardiology and Internal Diseases Almaty 050000 Kazakhstan Department Infectious Diseases Bogomolets National Medical University Kyiv 01601 Ukraine Department Infectious Diseases Belarus State Medical University Minsk 220116 Belarus Hepatology Ministry of Health Astana 010000 Kazakhstan Medical Affairs Mylan Pharmaceuticals Private Limited Kadubeesanahalli Bengaluru 560103 India

Globally, 69.6 million individuals were infected with hepatitis C virus (HCV) infection in 2016. Of the six major HCV genotypes (GT), the most predominant one is GT1, worldwide. The prevalence of HCV in Central Asia, which includes most of the Commonwealth of Independent states (CIS), has been estimated to be 5.8% of the total global burden. The predominant genotype in the CIS and Ukraine regions has been reported to be GT1, followed by GT3. Inadequate HCV epidemiological data, multiple socio-economic barriers, and the lack of regionspecific guidelines have impeded the optimal management of HCV infection in this region. In this regard, a panel of regional experts in the field of hepatology convened to discuss and provide recommendations on the diagnosis, treatment, and pre-, on-, and posttreatment assessment of chronic HCV infection and to ensure the optimal use of cost-effective antiviral regimens in the region. A comprehensive evaluation of the literature along with expert recommendations for the management of GT1-GT6 HCV infection with the antiviral agents available in the region has been provided in this review. This consensus document will help guide clinical decision-making during the management of HCV infection, further optimizing treatment outcomes in these regions.

关键词： Antiviral agents Commonwealth of Independent states Genotype Hepatitis C virus Sustained virologic response Ukraine

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A field-effect approach to directly profiling the localized states in monolayer MoS2

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Science Bulletin 2019年第15期64卷 1049-1055页

作者： Hao Wu Yuan Liu Zeyu Deng Hung-Chieh Cheng Dehui Li Jian Guo Qiyuan He Sen Yang Mengning Ding Yun-Chiao Huang Chen Wang Yu Huang Xiangfeng Duan Department of Materials Science and Engineering University of CaliforniaLos AngelesCA90095USA Department of Chemistry and Biochemistry University of CaliforniaLos AngelesCA90095USA California NanoSystems Institute University of CaliforniaLos AngelesCA90095USA

A fundamental understanding of the charge transport mechanism in two-dimensional semiconductors(e.g., MoS2) is crucial for fully exploring their potential in electronic and optoelectronic devices. By using monolayer graphene as the barrier-free contact to MoS2, we show that the field-modulated conductivity can be used to probe the electronic structure of the localized states. A series of regularly distributed plateaus were observed in the gate-dependent transfer curves. Calculations based on the variable-range hopping theory indicate that such plateaus can be attributed to the discrete localized states near mobility edge. This method provides an effective approach to directly profiling the localized states in conduction channel with an ultrahigh resolution up to 1 meV.

关键词： Two-dimensional layered materials Field-effect transistor Localized states Electronic transport Conductivity plateau

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Improved generation of correlated photon pairs from monolayer WS_2 based on bound states in the continuum

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Photonics Research 2019年第3期7卷 341-350页

作者： TIECHENG WANG ZHIXIN LI XIANGDONG ZHANG Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology

Entangled photons are the fundamental resource in quantum information processing. How to produce them efficiently has always been a matter of concern. Here we propose a new way to produce correlated photons efficiently from monolayer WS_2 based on bound states in the continuum(BICs). The BICs of radiation modes in the monolayer WS_2 are realized by designing the photonic crystal slab-WS_2-slab structure. The generation efficiency of correlated photon pairs from such a structure has been studied by using a rigorous quantum model of spontaneous parametric down-conversion with the plane wave expansion method. It is found that the generation efficiency of correlated photon pairs is greatly improved if the signal and idler fields are located at the BICs determined by the inverse scattering matrix of the structure. This is in contrast to the parametric down-conversion process for the enhanced generation of nonlinear waves if the pump field is located at the BICs determined by the scattering matrix of the structure. The generation rate of the correlated photon pairs can be improved by 7 orders of magnitude in some designed structures. The generated quantum signals are sensitive to the wavelength and exhibit narrowed relative line width, which is very beneficial for quantum information processing.

关键词： correlated photon pairs monolayer WS2 based bound states

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NEW SHAPE FACTOR FOR CORRESPONDING states PRINCIPLE

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Chinese Journal of Chemical Engineering 1997年第2期5卷 77-82页

作者：陈新志侯虞钧 Department of Chemical Engineering Zhejiang University

1 INTRODUCTIONThe CSP(Corresponding states Principle)has been considered to be a useful methodfor the prediction of fluid properties from a minimum amount of information.One ofits form,the shape factor methods is deve... 详细信息

关键词： corresponding states principle equation of state thermodynamic property

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A novel kind of multiple steady states characteristics in the dividing wall column

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Chinese Journal of Chemical Engineering 2019年第4期27卷 869-876页

作者： Erwei Song Zengxi Li Erqiang Wang School of Chemical Sciences University of Chinese Academy of Sciences

In this article, one kind of multiple steady states(MSS) phenomenon was investigated for a dividing wall column(DWC). The four-section model constructed in Aspen Plus was employed to simulate two DWC cases: mixture of n-hexane, n-heptane and n-octane;system of methanol, ethanol and n-propanol. It can be seen that there is a range of vapor split ratio in which multiple solutions of reflux ratio exist for fixed DWC configuration with the same feed and product streams. The width and the curve shapes of the MSS region, and the number of solutions change with the liquid split ratio. This MSS phenomenon was further explained using the component recovery around the prefractionator and the component recycling flow inside the DWC. This MSS phenomenon is helpful for DWC design by knowing the probable existence of multiple solutions in advance.

关键词： Dividing wall column Multiple steady states Vapor split ratio Liquid split ratio Recycling flow

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Dissipative preparation of Bell states with parallel quantum Zeno dynamics

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 57-62页

作者： Chong Yang DongXiao Li XiaoQiang Shao Center for Quantum Sciences and School of Physics Northeast Normal UniversityChangchun 130024China Center for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materialsand Technology of Ministry of EducationNortheast Normal UniversityChangchun 130024China

We propose a new mechanism, parallel quantum Zeno dynamics, to dissipatively prepare all Bell entangled states of the twoqubit system in the context of cavity quantum electrodynamics. This mechanism can provide two transition channels between ground states and two different dark states simultaneously, which efficiently speeds up the stabilization of the entanglement and suppresses the adverse influence of surrounding environments. In addition, there is no need for the initialization of quantum states and the Clauser-Horne-Shimony-Holt inequality can be violated in a finite temperature bath. The experimental feasibility is also studied by the state-of-the-art technique and a high fidelity about 99% can be achieved.

关键词： Bell states quantum Zeno dynamics quantum dissipation

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