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Determination of the rate equations for erbium nanoparticles at arbitrary concentrations and drastically enhanced non-radiative transitions

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NANOSCALE 2025年第24期17卷 14837-14847页

作者： Wu, Jinhua Liang, Zhang Sun, Hao Cui, Ying Ning, Cun-Zheng Shenzhen Technol Univ Coll Integrated Circuits & Optoelect Chips Shenzhen 518118 Peoples R China Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China

Erbium (Er)-based NaYF4 nanoparticles (ENPs) are important for many applications including imaging, communications, and biosensing, particularly at high Er concentrations. The rate equations (REs) are fundamental for understanding various transitions in ENPs. However, the REs and their various coefficients are determined only at the classical composition of similar to 2% Er and similar to 20% ytterbium (Yb) while focusing only on up-conversion processes. This paper aims to determine the coefficients of the REs through systematic characterization across the full range of Er levels (5%, 50%, 75%, and 100%), where both up- and down-conversions are important and careful calibration of visible and near-infrared emission bands is required. The parameter values of the REs were then obtained through curve fitting for arbitrary Er concentrations. We found that non-radiative transitions and energy-transfer processes increase quadratically with Er concentration. We discovered that the non-radiative transition from 4I11/2 to 4I13/2 increases with Er concentration and is orders of magnitude faster than other decay processes, exhibiting the highest down-conversion at 100% Er. Our study explains why high Er concentration nanoparticles typically exhibit weak up-conversion emission. Our results establish the REs for arbitrary Er concentrations for the first time, which can be used more generally for designing ENPs and understanding complex nonlinear processes.

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Editorial for the Special Issue on Quantum Dots Frontiers

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MICROMAChiNES 2023年第5期14卷

作者： Chen, Wei Hao, Junjie Shenzhen Technol Univ Coll Engn Phys Ctr Adv Mat Diagnost Technol Shenzhen Key Lab Ultraintense Laser & Adv Mat Tech Shenzhen 518118 Peoples R China Shenzhen Technol Univ Coll Integrated Circuits & Optoelect Chips Shenzhen 518118 Peoples R China

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Structural, electronic, elastic and thermal properties of Cr-doped U3Si2: A DFT study

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JOURNAL OF NUCLEAR MATERIALS 2023年 579卷

作者： Li, Qiao Qiu, Nianxiang Liu, Zhen Huang, Qing An, Peng Du, Shiyu Zhejiang Univ Technol Coll Chem Engn Hangzhou 310014 Peoples R China Chinese Acad Sci Ningbo Inst Mat Technol & Engn Engn Lab Adv Energy Mat Ningbo 315201 Zhejiang Peoples R China Harbin Engn Univ Mat Sci & Chem Engn Harbin 150001 Heilongjiang Peoples R China Ningbo Univ Technol Coll Elect & Informat Engn Ningbo 315211 Zhejiang Peoples R China China Univ Petr East China Sch Mat Sci & Engn Qingdao 266580 Peoples R China Milky Way Sustainable Energy Ltd Zhuhai Peoples R China

Alloying has been considered as an effective strategy to make up for the poor oxidation corrosion re-sistance of U3Si2. However, the theoretical studies on alloyed U3Si2 are rarely reported. In this study, the structural, electronic, elastic and thermal properties of 10at% Cr-doped U3Si2 were studied us-ing first principles calculations and semiclassical Boltzmann transport theory. Our results show that the U3Si1.5Cr0.5 phase is determined to be thermodynamically, dynamically and elastically stable, and U2.5Si2Cr0.5 phase is dynamically and elastically stable. U3Si1.5Cr0.5 is more stable than U2.5Si2Cr0.5 from the thermodynamic calculation results. From the calculated electronic structure results, a mixture of ionic and metallic bonds dominates the bonding of Cr-doped U3Si2. They are ductile materials compared to the brittleness of U3Si2 according to the results of B/G ratio, Cauchy pressure and Poisson's ratio. Moreover, U3Si1.5Cr0.5 is a nearly elastic isotropic material, while U2.5Si2Cr0.5 exhibits strong anisotropy. The thermal conductivity of Cr-alloyed U3Si2 is dominated by the electronic contribution at high temperature, which is lower than U3Si2 but higher than UO2 at service temperature and increases with temperature. There-fore, in addition to significantly improving the resistance to oxidation and corrosion of U3Si2, Cr doping can also convert the brittleness of U3Si2 into toughness and improve its machinability, albeit at the rea-sonable expense of some mechanical properties and thermal conductivities, while maintaining the high uranium density of U3Si2 fuel form. The results of this work may provide useful clues for the application and improvement of uranium silicide fuels.(c) 2023 Elsevier B.V. All rights reserved.

关键词： Cr-dopedU 3 Si 2 Electronic structure Mechanical property Thermal conductivity Toughened

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Multifunctional silk fabric via surface modification of nano-SiO2

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TEXTILE research JOURNAL 2020年第13-14期90卷 1616-1627页

作者： Gao, Li-Zhi Bao, Yu Cai, Hai-Hua Zhang, Ai-Ping Ma, Yan Tong, Xiao-Ling Li, Zhi Dai, Fang-Yin Southwest Univ State Key Lab Silkworm Genome Biol Chongqing Peoples R China Southwest Univ Coll Text & Garment Chongqing Engn Res Ctr Biomat Fiber & Modern Text Chongqing Peoples R China Southwest Univ Coll Biotechnol Key Lab Sericultural Biol & Genet Breeding Minist Agr & Rural Affairs Chongqing Peoples R China

Silk fabrics have poor resistance to ultraviolet (UV) light and to wrinkles. To improve these properties, we propose a finishing method of coating the silk fabric surface with nano-silica (nano-SiO2). The results show that the UV protective factor (UPF) value could reach a maximum of 84.52 after finishing in 10 g/L nano-SiO2 and 20 g/L silane coupling agent (KH570) solution at 80celcius. Moreover, the treated silk fabrics showed improved wrinkle resistance and hydrophobicity. The surface morphology and crosslink action of the treated silk fabrics were characterized by scanning electron microscope, energy dispersive spectrometer and Fourier transform infrared spectroscopy, which proved that nano-SiO2 particles were grafted on to the silk fabric. There was no apparent difference in color between untreated and treated silk fabrics. Thermal stability and cytotoxicity tests showed that the treated silk fabrics had good thermostability and cytocompatibility. The UPF value could be maintained at 77.31 after washing 20 times, which demonstrated that the treated silk fabrics had laundry resistance. Multifunctional silk fabrics with good hydrophobic properties and excellent UV and wrinkle resistance were developed, showing good prospects for their application in self-cleaning, protective and non-ironing clothes.

关键词： silk fabrics nano-silica coating anti-ultraviolet wrinkle resistance hydrophobicity

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Toward Safe Retinal Microsurgery: development and Evaluation of an RNN-Based Active Interventional Control Framework

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IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING 2020年第4期67卷 966-977页

作者： He, Changyan Patel, Niravkumar Shahbazi, Mahya Yang, Yang Gehlbach, Peter Kobilarov, Marin Iordachita, Iulian Beihang Univ Sch Mech Engn & Automat Beijing 100191 Peoples R China Johns Hopkins Univ Lab Computat Sensing & Robot Baltimore MD 21218 USA Johns Hopkins Univ Hosp Wilmer Eye Inst Baltimore MD 21287 USA

Objective: Robotics-assisted retinal microsurgery provides several benefits including improvement of manipulation precision. The assistance provided to the surgeons by current robotic frameworks is, however, a "passive" support, e.g., by damping hand tremor. Intelligent assistance and active guidance are, however, lacking in the existing robotic frameworks. In this paper, an active interventional control framework (AICF) has been presented to increase operation safety by actively intervening the operation to avoid exertion of excessive forces to the sclera. Methods: AICF consists of the following four components: first, the steady-hand eye robot as the robotic module;second, a sensorized tool to measure tool-to-sclera forces;third, a recurrent neural network to predict occurrence of undesired events based on a short history of time series of sensor measurements;and finally, a variable admittance controller to command the robot away from the undesired instances. Results: A set of user studies were conducted involving 14 participants (with four surgeons). The users were asked to perform a vessel-following task on an eyeball phantom with the assistance of AICF as well as other two benchmark approaches, i.e., auditory feedback (AF) and real-time force feedback (RF). Statistical analysis shows that AICF results in a significant reduction of proportion of undesired instances to about 2.5%, compared with 38.4% and 26.2% using AF and RF, respectively. Conclusion: AICF can effectively predict excessive-force instances and augment performance of the user to avoid undesired events during robot-assisted microsurgical tasks. Significance: The proposed system may be extended to other fields of microsurgery and may potentially reduce tissue injury.

关键词： Medical robotics recurrent neural network retinal surgery safety in microsurgery

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sgBE: a structure-guided design of sgRNA architecture specifies base editing window and enables simultaneous conversion of cytosine and adenosine

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GENOME BIOLOGY 2020年第1期21卷 1-16页

作者： Wang, Yanhong Zhou, Lifang Tao, Rui Liu, Nan Long, Jie Qin, Fengming Tang, Wenling Yang, Yang Chen, Qiang Yao, Shaohua Sichuan Univ Lab Biotherapy Natl Key Lab Biotherapy Canc CtrWest China Hosp Renmin Nanlu 17 Chengdu 610041 Sichuan Peoples R China

We present a base editing system, in which base editors are attached to different sites of sgRNA scaffold (sgBE). Each independent sgBE has its own specific editing pattern for a given target site. Among tested sgBEs, sgBE-SL4, in which deaminase is attached to the last stem-loop of sgRNA, yields the highest editing efficiency in the window several nucleotides next to the one edited by BE3. sgBE enables the simultaneous editing of adenine and cytosine. Finally, in order to facilitate in vivo base editing, we extend our sgBE system to an AAV-compatible Cas9, SaCas9 (Staphylococcus aureus), and observe robust base editing.

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Measuring Residual Magnetic Field in the Magnetic Shield with Magnetic Resonance Signal Width

Measuring Residual Magnetic Field in the Magnetic Shield wit...

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Joint Conference of the IEEE International Frequency Control Symposium (IEEE IFCS) and IEEE International Symposium on Applications of Ferroelectrics (IEEE IFAS)

作者： Yang, Yucheng Chen, Jingbiao Peng, Xiang Wu, Teng Guo, Hong Peking Univ State Key Lab Adv Opt Commun Syst & Networks Dept Elect Beijing 100871 Peoples R China Peking Univ Ctr Quantum Informat Technol Beijing 100871 Peoples R China

ISBN: (纸本)9781728164304

In this article, we present a novel method to measure the residual magnetic field in the magnetic shield. Because of the nonlinear Zeeman effect, the magnetic resonance width will grow with the increasing magnetic field. By detecting the dependence of the magnetic resonance signal width on the applied magnetic field, the residual magnetic field in the magnetic shield can be deduced. The error of the deduced value and the true value can be less than 1.5 nT. higher sampling rate can result in less error.

关键词： magnetic resonance magnetic shield vapor cell nonlinear Zeeman effect

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A novel insight into the preparation method of Pd/Ce0.75Zr0.25O2-Al2O3 over high-stability close coupled catalysts

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APPLIED SURFACE SCIENCE 2019年 467卷 723-739页

作者： Sun, Min Hu, Wei Cheng, Tianqiong Chen, Yusheng Yao, Peng Zhao, Ming Yuan, Shandong Chen, Yaoqiang Sichuan Univ Coll Chem Chengdu 610064 Sichuan Peoples R China Sichuan Univ Coll Chem Engn Chengdu 610064 Sichuan Peoples R China Sichuan Univ Inst New Energy & Low Carbon Technol Chengdu 610064 Sichuan Peoples R China

A series of Ce0.75Zr0.25O2-Al2O3 samples were prepared by conventional coprecipitation, wet impregnation method and novel deposition precipitation, after the corresponding Pd-only close coupled catalysts were obtained by incipient wet impregnation. Differences in surface properties and catalytic performance were investigated systematically by a wealth of characterizations. XPS, H-2-TPR and CO chemisorption revealed that the different preparation methods of Ce0.75Zr0.25O2-Al2O3 led to different intensity of interaction between PdO species and support, thus forming different palladium dispersions. BET, XRD and activity evaluation indicated the catalyst obtained by novel deposition precipitation presented superior textural properties, catalytic performance and thermal stability, due to the strongest interaction proved by H-2-TPR, XPS and CO chemisorption, which could retard the sintering of noble metal during the aging process. HRTEM images indicate for the catalysts, PdO species are mainly dispersed and stabilized on the ceria resulting from the lower redox potential of Pd2+/Pd-0 (0.95 V) than that of Ce4+/Ce3+ (1.72 V). Consequently, it owned higher surface PdO content and dispersion than the catalysts prepared by coprecipitation and impregnation method, presenting its higher catalytic properties.

关键词： Thermal stability Preparation method Interaction Palladium dispersion Catalytic performance

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Identification and effect of Zf-AD-containing C2H2 zinc finger genes on BmNPV replication in the silkworm (Bombyx mori)

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PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020年 170卷 104678页

作者： Li, Chunlin Zhang, Hao Gao, Rui Zuo, Weidong Liu, Yanyu Hu, Hai Luan, Yue Lu, Cheng Tong, Xiaoling Dai, Fangyin Southwest Univ Key Lab Sericultural Biol & Genet Breeding Minist Agr & Rural Affairs State Key Lab Silkworm Genome BiolColl Biotechno Chongqing 400715 Peoples R China

Zf-AD-containing C2H2 zinc-finger genes (ZAD) are uniquely present and have lineage-specific expansion in arthropods. Arthropods are also the hosts of Baculoviruses. We studied the possible relationship between the lineage-specific expansion of ZAD genes and arthropod-Baculovirus co-evolution. We used the silkworm (Bombyx mori) as a model. We identified 73 ZAD genes (BmZAD) in the silkworm. Sequence-based similarity analysis showed that nine clusters involving 28 BmZADs may have undergone species-specific expansion in the silkworm. Expression pattern analysis showed that the BmZADs were divided into five groups. Group I comprised 10 genes with high expression in multiple tissues, suggesting that BmZADs may play roles in the development of various tissues. We identified six BmZADs that could be induced by the Nucleopolyhedrovirus (BmNPV). Among them, BmZAD69 expression is capable of responding to BmNPV infection, and the ZAD domain is indispensable for the function of BmZAD69 in BmNPV replication. We also detected a 3 bp deletion at 1.7 kb upstream of BmZAD69, which may make it more sensitive to BmNPV infection, and thus elevate the BmNPV resistance in Qiufeng_N, a strain with strong virus resistance. These data suggest that BmZADs may be involved in BmNPV infection and that ZAD genes may play a role in arthropod-Baculovirus co-evolution.

关键词： ZAD domain Lineage-specific expansion Arthropods-Baculovirus co-evolution Silkworm BmNPV

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highly Stable Single-Atom Modified MXenes as Cathode-Active Bifunctional Catalysts in Li-CO2 Battery

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ADVANCED FUNCTIONAL MATERIALS 2022年第48期32卷

作者： Shi, Yu Wei, Bo Legut, Dominik Du, Shiyu Francisco, Joseph S. Zhang, Ruifeng Beihang Univ Sch Mat Sci & Engn Beijing 100191 Peoples R China Beihang Univ Minist Ind & Informat Technol Int Res Inst Multidisciplinary Sci Ctr Integrated Computat Mat Engn Beijing 100191 Peoples R China Beihang Univ Minist Ind & Informat Technol Key Lab High Temp Struct Mat & Coatings Technol Beijing 100191 Peoples R China VSB Tech Univ Ostrava IT4Innovat 17 Listopadu 2172-15 CZ-70800 Ostrava Czech Republic Chinese Acad Sci Ningbo Inst Mat Technol & Engn Engn Lab Specialty Fibers & Nucl Energy Mat Ningbo 315201 Zhejiang Peoples R China Univ Penn Dept Earth & Environm Sci Philadelphia PA 19104 USA Univ Penn Dept Chem Philadelphia PA 19104 USA

The exploration of cathode catalysts with low overpotentials for the carbon dioxide reduction reaction (CRR) and carbon dioxide evolution reaction (CER) is essential for Li-CO2 batteries. MXenes have been suggested as potential candidates owing to their high electrical conductivity and effective CO2 activation performance. Herein, the stability and bifunctional CRR/CER catalytic activities of bare MXene (M2C), oxygen-functionalized MXene (M2CO2), and single-atom (SA) modified M2CO2 are systemically investigated. Among bare MXenes, Mo2C exhibits the best catalytic activity, comparable to that of carbon nanotubes, whereas oxygen-functionalized MXene has poor activity. Notably, introducing an SA on the surface of oxygen-functionalized MXene decreases the overpotential by 12.2%-68.1%, which can even outperform graphene catalysts, suggesting their potential as bifunctional cathode catalysts in Li-CO2 batteries. This high activity is appropriate reactivity in origin, as highlighted by the volcano-type relationship between the Gibbs free energy and the overpotential for key steps. The descriptor xi, which is related to adsorption behavior, is effective in determining bifunctional catalytic activity, which depends on the ability of SA electrons to fill antibonding orbitals and SA-oxygen/carbon bonding. This work not only identifies promising MXene-based bifunctional CRR/CER catalysts but also provides a rational design rule for SA modified catalysts.

关键词： density functional theory Li-CO (2) batteries MXenes single-atom modified catalysts

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