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Photocatalyzed ditrifluoromethylthiolation of alkenes with CF_(3)SO_(2)Na

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Science China Chemistry 2024年第2期67卷 587-594页

作者： Fangming chen Lvqi Jiang Chunyang hu Jie Liu wenbin Yi School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Organofluorine Chemistry Shanghai Institute Organic ChemistryChinese Academy of SciencesShanghai200032China

Since the first report of sodium trifluoromethanesulfinate(CF_(3)SO_(2)Na) as an electrophilic trifluoromethylthiolation reagent in 2015,there has been no breakthrough in research in this ***,we disclose an unprecedented usage of CF_(3)SO_(2)Na as a radical trifluoromethylthiolation reagent.A photocatalyzed ditrifluoromethylthiolation of alkenes with CF_(3)SO_(2)Na in the presence of PPh_(3) and catalytic copper has been ***,either Ir[(p-Fppy)_(2)(bpy)]PF_6 or Ir(ppy)_(3) could facilitate this *** studies indicate that initiation of the radical chain proceeded via two different photocatalytic quenching *** protocol provides a practical method for the construction of diverse vicinal ditrifluoromethylthiolated compounds.

关键词： trifluoromethylthiolation photocatalysis radical difunctionalization alkenes

A universal and ultrafast method for fabricating a library of nanocellulose-supported metal nanoparticles

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Progress in Natural Science:Materials International 2024年第2期34卷 389-395页

作者： Ziyi Luo Xiaoyang Wang Baihua Cui Hao Luo Tao Zhang Jia Ding Yanan chen Yida Deng wenbin hu School of Materials Science and Engineering Tianjin University Department of Chemistry National University of Singapore State Key Laboratory of Marine Resource Utilization in South China Sea School of Materials Science and Engineering Hainan University

Using nanocatalysts to catalyze water electrolysis for hydrogen production is an ideal solution to address the energy *** most well-adopted fabrication methods for nanocatalysts are tube furnace annealing,Hydrothermal method,etc.,hardly satisfying the trade-off among coarsening,dispersity,and particle size due to mutual ***,a universal,ultrafast and facile cellulose nanometer whiskers-high temperature shock（CNWHTS） method was reported for fabricating a library of ultrafine metal nanoparticles with uniform dispersion and narrow size *** metal-anchor functional groups in CNW（i.e.,-OH and-COOH） and the characteristics of the HTS method for ultrafast heating and powerful quenching synergistically contribute to the successful synthesis of metal *** an initial demonstration,the as-prepared Pt nanocatalyst(η10 mA cm-2=51.8 mV) shows more excellent catalytic hydrogen evolution reaction（HER） performance than the Pt catalyst prepared in the tubular furnace(η10 mA cm-2=169.4 mV).This rapid and universal CNW-HTS method can pave the way for nanomanufacturing to produce high-quality metal nanoparticles,thereby expanding applications of energy conversion and electrocatalysis.

关键词： Electrocatalysis High-temperature shock Hydrogen evolution reaction (HER) Nanocellulose Nanomanufacturing Nanoparticles

Distributed phase-matching measurement for dynamic strain and temperature sensing based on stimulated Brillouin scattering enhanced four-wave mixing

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Photonics Research 2024年第1期12卷 141-153页

作者： YUAN WANG PEDRO TOVAR JUNTONG YANG LIANG chen xiaoyi BAO Nexus for Quantum Technologies University of OttawaOttawaOntario K1N 6N5Canada

A Brillouin dynamic grating(BDG) can be used for distributed birefringence measurement in optical fibers,offering high sensitivity and spatial resolution for sensing ***,it is quite a challenge to simultaneously achieve dynamic measurements with both high accuracy and high spatial *** this work,we propose a sensing mechanism to achieve distributed phase-matching measurement using a chirped pulse as a probe *** BDG reflection,the peak reflection corresponds to the highest four-wave mixing(FWM) conversion efficiency,and it requires the Brillouin frequency in the fast and slow axes to be equal,which is called the phase-matching *** condition changes at different fiber positions,which requires a range of frequency injection for the probe *** proposed method uses a chirped pulse as a probe wave to cover this frequency range associated with distributed birefringence *** allows us to detect distributed phase matching for birefringence changes that are introduced by temperature and strain *** to the single shot and direct time delay measurement capability,the acquisition rate in our system is only limited by the fiber ***,unlike conventional BDG spectrum recovery-based systems,the spatial resolution here is determined by both the frequency chirping rate of the probe pulse and the birefringence profile of the *** the experiments,an acquisition rate of 1 k Hz(up to fiber length limits) and a spatial resolution of 10 cm using a 20 ns probe pulse width are *** minimum detectable temperature and strain variation are 5.6 mK and 0.37 με along a 2 km long polarization-maintaining fiber(PMF).

关键词： fiber scattering polarization

Boosting cycling stability by regulating surface oxygen vacancies of LNMO by rapid calcination

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Nano Research 2024年第4期17卷 2671-2677页

作者： Haoran Jiang Cuihua Zeng Wei Zhu Jiawei Luo Zhedong Liu Jingchao Zhang Rui Liu Yunhua Xu Yanan chen wenbin hu School of Materials Science and Engineering Tianjin UniversityTianjin 300072China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China

Spinel LiNi_(0.5-x)Mn_(1.5+x)O_(4)(LNMO)has attracted intensive interest for lithium-ion battery due to its high voltage and high energy ***,severe capacity fade attributed to unstable surface structure has hampered its *** vacancies(OVs)tend to occur in the surface of the material and lead to surface structure reconstruction,which deteriorates the battery performance during electrochemical ***,we utilize high-temperature-shock(HTS)method to synthesize LNMO materials with fewer surface *** calcination drives lower surface OVs concentration,reducing the content of Mn^(3+)and surface reconstruction layers,which is beneficial to obtain a stable crystal *** LNMO material synthesized by HTS method delivers an initial capacity of 127 mAh·g^(-1) at 0.1 C and capacity retention of 81.6%after 300 cycles at 1 C,and exhibits excellent performance at low temperature.

关键词： ultrafast synthesis oxygen vacancy LiNi_(0.5-x)Mn_(1.5+x)O_(4)(LNMO)cathode high-temperature-shock lithium-ion batteries

Regulation of the pore structure of carbon nanosheets based electrocatalyst for efficient polysulfides phase conversions

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Journal of Materials Science & Technology 2024年第4期171卷 37-46页

作者： Xiaoyang Liu Jingbo Zhang Kangli Liu Shijie Zhang Rouhan Hou xiaoyi hu Peng Zhang Guosheng Shao State Center for International Cooperation on Designer Low-Carbon&Environmental Materials(CDLCEM) School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China Zhengzhou Materials Genome Institute(ZMGI) Xingyang 450100China

The practical applications of lithium-sulfur(Li-S)batteries are hampered by the sluggish redox kinetics and polysulfides shuttle in the cyclic process,which leads to a series of problems including the loss of active materials and poor cycling *** this paper,the pore structures of carbon nanosheets based electrocatalysts were precisely controlled by regulating the content of water-soluble KCl *** relationship between pore structures and Li-S electrochemical behavior was studied,which demonstrates a key influence of pore structure in polysulfides phase *** the liquid-sloid redox reaction of polysulfides,the micropores and small mesopores(d20 nm)and macropores played a decisive *** a typical exhibition,the nickel-embedded carbon nanosheets(Ni-CNS)with a high content of large mesopores and macropores can aid Li-S batteries in exhibiting stable cycling performance(760.1 mAh g^(-1)at 1 C after 300 cycles)and superior rate capac-ity(847.8 mAh g^(-1)at 2 C).Furthermore,even with high sulfur loading(8 mg cm^(−2))and low electrolyte(E/S is around 6μL mg^(-1)),the high area capacity of 7.7 mAh cm^(−2)at 0.05 C could be *** work can provide a guideline for the design of the pore structure of carbon-based electrocatalysts toward high-efficiency sulfur species redox reactions,and afford a general,controllable,and simple approach to constructing high performance Li-S batteries.

关键词： Hierarchical porous carbon network Electrocatalyst Molten salt templating method Modified separators Li-S batteries

A functional gel polymer electrolyte based on PVDF-HFP/gelatin toward dendrite-free lithium metal batteries

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Nano Research 2024年第4期17卷 2790-2799页

作者： xiaoyi hu Kangli Liu Shijie Zhang Guosheng Shao S.Ravi P.Silva Peng Zhang State Center for International Cooperation on Designer Low-carbon and Environmental Materials(CDLCEM) School of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China Zhengzhou Materials Genome Institute(ZMGI) ZhongyuanzhiguXingyang 450100China Nanoelectronics Center Advanced Technology InstituteUniversity of SurreyGuildfordGU27XHUK

The leakage of liquid electrolyte and the formation of lithium dendrites pose challenges to safety and stability of lithium metal batteries(LMBs).The appearance of gel polymer electrolyte(GPE)has obviously improved the safety of traditional ***,the limited inhibition of GPE on lithium dendrites is detrimental to the safety of ***,a kind of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)/gelatin(GN)GPE with high ionic conductivity,high-temperature resistance,and flame-retardancy,was prepared by electrospinning and soaking *** the electrospinning network of PVDF-HFP,its affinity to liquid electrolytes,makes this GPE more beneficial to ions transport and the formation of ***,the GN with sol–gel properties,enhances the mechanical property(13.5 MPa)of HFP-GN ***,X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)suggest that the attraction of polar groups of GN to Li+can regulate the distribution of Li+and protect Li ***,the application of HFP-GN GPEs to LMBs with cathodes of LiFePO_(4) and LiCoO_(2) deliver excellent electrochemical performances:after 300 cycles,the LiFePO_(4)/HFP-GN GPE/Li battery keeps a low capacity decay rate of 0.09%at 5 C;after 400 cycles at 2 C,the LiCoO_(2)/HFP-GN GPE/Li cell retains a high capacity retention of 74%.This GPE is demonstrated for the application prospect of safe LMBs.

关键词： poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP) gelatin polar groups lithium metal battery lithium dendrite

Approaching Ultimate Synthesis Reaction Rate of Ni-Rich Layered Cathodes for Lithium-Ion Batteries

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Nano-Micro Letters 2024年第10期16卷 392-402页

作者： Zhedong Liu Jingchao Zhang Jiawei Luo Zhaoxin Guo Haoran Jiang Zekun Li Yuhang Liu Zijing Song Rui Liu Wei-Di Liu wenbin hu Yanan chen School of Materials Science and Engineering Tianjin UniversityTianjin 300072People's Republic of China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590People's Republic of China Australian Institute of Bioengineering and Nanotechnology The University of QueenslandSt LuciaQLD 4072Australia

Nickel-rich layered oxide LiNi_(x)Co_(y)MnzO_(2)(NCM,x+y+z=1)is the most promising cathode material for high-energy lithium-ion ***,conventional synthesis methods are limited by the slow heating rate,sluggish reaction dynamics,high energy consumption,and long reaction *** overcome these chal-lenges,we first employed a high-temperature shock(HTS)strategy for fast synthesis of the NCM,and the approaching ultimate reaction rate of solid phase transition is deeply investigated for the first *** the HTS process,ultrafast average reaction rate of phase transition from Ni_(0.6)Co_(0.2)Mn_(0.2)(OH)_(2) to Li-containing oxides is 66.7(%s^(-1)),that is,taking only 1.5 *** ultrahigh heating rate leads to fast reaction kinetics,which induces the rapid phase transition of NCM *** HTS-synthesized nickel-rich layered oxides perform good cycling performances(94%for NCM523,94%for NCM622,and 80%for NCM811 after 200 cycles at 4.3 V).These findings might also assist to pave the way for preparing effectively Ni-rich layered oxides for lithium-ion batteries.

关键词： Nickel-rich layered oxides High-temperature shock Solid reaction kinetics Phase transition Reaction rate

Resurvey After 20 Years:Updating the Distribution,Population,and Potential Threats of the Chinting Alpine Toad

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Asian Herpetological Research 2024年第2期15卷 73-81页

作者： Yuezheng FAN Qingfeng chen Yuwen chenG Kaicheng TANG Ling SUN Yonghao huANG Lan ZHAO Dong LIANG xiaoyi WANG Junhua hu chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041SichuanChina University of Chinese Academy of Sciences Beijing 100049China The State-owned Forest Farm of Hongya County Meishan 620360SichuanChina Sichuan Mt.Emei Forest Ecosystem National Observation and Research Station Leshan 614201SichuanChina

Considering the increased anthropogenic impacts,species with a limited range and low detectability often lack fundamental information and conservation actions,placing them at a high risk of *** Chinting alpine toad Scutiger chintingensis is a rare mountain amphibian endemic to the eastern margin of the Qinghai-Xizang Plateau in *** its whole distribution range,only three known populations(Wolong,Emei,and Wawu)exist and no recent population status report has been documented for this species over the past two *** 2020 to 2023,we investigated the species distribution,and assessed the risk factors for the main *** recorded this species in all distribution areas,and updated a new distribution site with a lower elevation *** relative population density was 0.024±0.012 ind./m^(2)on Mount Emei,whereas only 0.008±0.017 ind./m^(2)on Mount *** significant difference was observed in the number of individuals between the two populations;however,the relative population density was significantly *** and waste discharge resulting from the construction of scenic areas,as well as disturbances from tourism,were the primary anthropogenic factors that influenced the survival of this *** results provide the updated information on the distribution and population status of the Chinting alpine toad,and suggest that unrecorded populations,as well as a wider elevation range,may exist for this *** findings emphasise the importance of timely updates of species distribution and population information and offer a basis for the future conservation of endangered amphibians.

关键词： distribution endemic amphibian population size Scutiger chintingensis threat factor

An improved interval model updating method via adaptive Kriging models

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 497-514页

作者： Sha WEI Yifeng chen hu DING Liqun chen Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

Interval model updating(IMU)methods have been widely used in uncertain model updating due to their low requirements for sample ***,the surrogate model in IMU methods mostly adopts the one-time construction *** makes the accuracy of the surrogate model highly dependent on the experience of users and affects the accuracy of IMU ***,an improved IMU method via the adaptive Kriging models is *** method transforms the objective function of the IMU problem into two deterministic global optimization problems about the upper bound and the interval diameter through universal grey *** optimization problems are addressed through the adaptive Kriging models and the particle swarm optimization(PSO)method to quantify the uncertain parameters,and the IMU is *** the construction of these adaptive Kriging models,the sample space is gridded according to sensitivity *** sampling is then performed in key subspaces based on the maximum mean square error(MMSE)*** interval division coefficient and random sampling coefficient are adaptively adjusted without human interference until the model meets accuracy *** effectiveness of the proposed method is demonstrated by a numerical example of a three-degree-of-freedom mass-spring system and an experimental example of a butted cylindrical *** results show that the updated results of the interval model are in good agreement with the experimental results.

关键词： interval model updating(IMU) non-probabilistic uncertainty adaptive Kriging model surrogate model grey number