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Enhanced stability of nitrogen-doped carbon-supported palladium catalyst for oxidative carbonylation of phenol

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Chinese Journal of Chemical Engineering 2024年第1期65卷 19-28页

作者： Xiaojing Liu Ruohan zhao Hao zhao Zhimiao Wang Fang Li Wei Xue Yanji Wang Hebei Provincial Key Laboratory of Green Chemical Technology and High Efficient Energy Saving School of Chemical Engineering and TechnologyHebei University of TechnologyTianjin 300130China Tianjin Key Laboratory of Chemical Process Safety Tianjin 300130China Hebei Industrial Technology Research Institute of Green Chemical Industry Huanghua 061100China

Enhancing the stability of supported noble metal catalysts emerges is a major challenge in both science and ***,a heterogeneous Pd catalyst(Pd/NCF)was prepared by supporting Pd ultrafine metal nanoparticles(NPs)on nitrogen-doped carbon;synthesized by using F127 as a stabilizer,as well as chitosan as a carbon and nitrogen *** Pd/NCF catalyst was efficient and recyclable for oxidative carbonylation of phenol to diphenyl carbonate,exhibiting higher stability than Pd/NC prepared without F127 *** hydrogen bond between chitosan(CTS)and F127 was enhanced by F127,which anchored the N in the free amino group,increasing the N content of the carbon material and ensuring that the support could provide sufficient N sites for the deposition of Pd *** process helped to improve metal *** increased metal-support interaction,which limits the leaching and coarsening of Pd NPs,improves the stability of the Pd/NCF ***,density functional theory calculations indicated that pyridine N stabilized the Pd^(2+)species,significantly inhibiting the loss of Pd^(2+)in Pd/NCF during the reaction *** work provides a promising avenue towards enhancing the stability of nitrogen-doped carbon-supported metal catalysts.

关键词： Supported Pd catalyst N-doped carbon Amphiphilic triblock copolymer Pyridinic nitrogen Stability

UniBind:a novel artificial intelligence-based prediction model for SARS-CoV-2 infectivity and variant evolution

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Signal Transduction and Targeted Therapy 2024年第1期9卷 14-15页

作者： Qihong Yan Jincun zhao State Key Laboratory of Respiratory Disease National Clinical Research Center for Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina

In a recent study published in Nature Medicine,Wang et *** an excellent framework called UniBind based on artificial intelligence(AI),which enables accurately predicting infectivity of SARS-CoV-2 variants and evolutionary trends of future viral variants.1 This computational method holds the possibility to not only serve as a valuable early-warning tool for monitoring potential pathogenic SARS-CoV-2 variants but also facilitate fundamental research on protein-protein interactions(PPIs).

关键词： artificial Bind prediction

Two Matrix Theorems Arising from Nilpotent Groups

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ALGEBRA COLLOQUIUM 2024年第3期31卷 499-504页

作者： zhao, Jing Liu, Heguo Hainan Univ Sch Math & Stat Haikou 570228 Peoples R China

For a nilpotent group G without pi-torsion, and x, y is an element of G , if x(n) = y(n) for a pi-number n, then x=y ; if x(m) y(n) = y(n) x(m) for pi-numbers m, n, then xy = yx . This is a well-known result in group theory. In this paper, we prove two analogous theorems on matrices, which have independence significance. Specifically, let m be a given positive integer and A a complex square matrix satisfying that (i) all eigenvalues of A are nonnegative, and (ii) rank A(2) = rank A; then A has a unique m-th root X with rank X-2 = rank X , all eigenvalues of X are nonnegative, and moreover there is a polynomial f( lambda) with X = f (A). In addition, let A and B be complex nxn matrices with all eigenvalues nonnegative, and rank A(2) = rank A, rank B-2 = rank B; then (i) A=B when A (R) = B (R) for some positive integer r, and (ii) AB = BA when A(s) B-t = B-t A(s) for two positive integers s and t.

关键词： nilpotent group root matrix Chinese remainder theorem

Passivity-Based Stabilization for Switched Stochastic Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1307-1309页

作者： Yaowei Sun Jun zhao School of Automation Zhengzhou University of AeronauticsZhengzhou 450046 Henan Key Laboratory of General Aviation Technology Zhengzhou University of AeronauticsZhengzhou 450046China College of Information Science and Engineering Northeastern UniversityShenyang 110819China

Dear Editor,This letter addresses the passivity-based mean square exponential stabilization problem for switched stochastic nonlinear systems.A concept of generalized small-time norm-observability is presented and an appropriate test condition is also *** pre-given passivity rate and average dwell time,a set of feedback controllers is designed by use of the passivity property.

关键词： property letter stabilization

Leakage and diffusion characteristics of underground hydrogen pipeline

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Petroleum 2024年第2期10卷 319-325页

作者： Wenkang Zhang Guanghui zhao School of Mechatronic Engineering Southwest Petroleum University

Soil corrosion and hydrogen embrittlement are the main factors of hydrogen pipeline failure. The gas escapes, diffuses and accumulates in the soil and enters the atmosphere when leak occurs. The mechanism of gas diffusion in buried pipelines is very complicated. Mastering the evolution law of hydrogen leakage diffusion is conducive to quickly locating the leakage point and reducing the loss. The leakage model of the underground hydrogen pipeline is established in this paper. The effect of leakage hole, soil type, pipeline pressure, pipeline diameter on hydrogen leakage diffusion were investigated. The results show that when the hydrogen pipeline leaks, the hydrogen concentration increases with the increase of leakage time, showing a symmetrical distribution trend. With the pipeline pressure increase, hydrogen leakage speed is accelerated, and longitudinal diffusion gradually becomes the dominant direction. As the leakage diameter increases, hydrogen leakage per unit of time increases sharply. Hydrogen diffuses more easily in sandy soil, and its diffusion speed, concentration, and range are higher than that in clay soil. The research content provides a reference and basis for the detection and evaluation of buried hydrogen pipeline leakage.

关键词： Buried pipeline Hydrogen leakage Diffusion characteristics Numerical simulation

A sub-grid scale model for Burgers turbulence based on the artificial neural network method

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 162-165页

作者： Xin zhao Kaiyi Yin Department of Mechanics Beijing Institute of TechnologyBeijing 100081China

The present study proposes a sub-grid scale model for the one-dimensional Burgers turbulence based on the neuralnetwork and deep learning *** filtered data of the direct numerical simulation is used to establish thetraining data set,the validation data set,and the test data *** artificial neural network(ANN)methodand Back Propagation method are employed to train parameters in the *** developed ANN is applied toconstruct the sub-grid scale model for the large eddy simulation of the Burgers turbulence in the *** proposed model well predicts the time correlation and the space correlation of the Burgers turbulence.

关键词： Artificial neural network Back propagation method Burgers turbulence Large eddy simulation Sub-grid scale model

A Lightweight, Searchable, and Controllable EMR Sharing Scheme

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Computers, Materials & Continua 2024年第4期79卷 1521-1538页

作者： Xiaohui Yang Peiyin zhao School of Cyber Security and Computer Hebei UniversityBaoding071000China

Electronic medical records (EMR) facilitate the sharing of medical data, but existing sharing schemes suffer fromprivacy leakage and inefficiency. This article proposes a lightweight, searchable, and controllable EMR sharingscheme, which employs a large attribute domain and a linear secret sharing structure (LSSS), the computationaloverhead of encryption and decryption reaches a lightweight constant level, and supports keyword search andpolicy hiding, which improves the high efficiency of medical data sharing. The dynamic accumulator technologyis utilized to enable data owners to flexibly authorize or revoke the access rights of data visitors to the datato achieve controllability of the data. Meanwhile, the data is re-encrypted by Intel Software Guard Extensions(SGX) technology to realize resistance to offline dictionary guessing attacks. In addition, blockchain technology isutilized to achieve credible accountability for abnormal behaviors in the sharing process. The experiments reflectthe obvious advantages of the scheme in terms of encryption and decryption computation overhead and storageoverhead, and theoretically prove the security and controllability in the sharing process, providing a feasible solutionfor the safe and efficient sharing of EMR.

关键词： Lightweight keyword search large attribute domain controllability blockchain

Monolayer mesoporous nanosheets with surface asymmetry via a dual-emulsion-directed monomicelle assembly

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λ/20-Thick cavity for mimicking electromagnetically induced transparency at telecommunication wavelengths

结构化学 2024年第2期43卷 1-3页

作者： Yujuan zhao Zaiwang zhao College of Energy Materials and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot010070China

Functional mesoporous materials,based on IUPAC,are a type of porous materials with a uniform pore size ranging from 2 to 50 *** the 1980s,the existing zeolites or microporous materials with small pore sizes(less than 1.2 nm)have some limitations in practical applications,especially for large molecule conversion and *** by these motivations,the exploration of mesoporous materials has been widely *** the early 1990s,the mesoporous materials including or-dered M41S[1]mesoporous silicate molecular sieves and large-pore mesoporous silica SBA-15[2]were prepared when templated by the quaternary ammonium cationic surfactant or the amphiphilic triblock copolymer *** high thermal stability of such porous materials and good repeatability of methods have aroused widespread interest in both academic and industrial domains.

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Advanced Photonics 2024年第3期6卷 42-50页

作者： Hua Lu Shouhao Shi Dikun Li Shuwen Bo Jianxu zhao Dong Mao Jianlin zhao Northwestern Polytechnical University School of Physical Science and Technology MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions Key Laboratory of Light-Field Manipulation and Information Acquisition Ministry of Industry and Information TechnologyShaanxi Key Laboratory of Optical Information Technology

Optical cavities play crucial roles in enhanced light–matter interaction, light control, and optical communications, but their dimensions are limited by the material property and operating *** planar cavities are urgently in demand for large-area and integrated optical devices. However,extremely reducing the planar cavity dimension is a critical challenge, especially at telecommunication wavelengths. Herein, we demonstrate a type of ultrathin cavities based on large-area grown Bi2Te3topological insulator（TI） nanofilms, which present distinct optical resonance in the near-infrared region. The result shows that the Bi2Te3TI material presents ultrahigh refractive indices of >6 at telecommunication wavelengths. The cavity thickness can approach 1/20 of the resonance wavelength, superior to those of planar cavities based on conventional Si and Ge high refractive index materials. Moreover, we observed an analog of the electromagnetically induced transparency（EIT） effect at telecommunication wavelengths by depositing the cavity on a photonic crystal. The EIT-like behavior is derived from the destructive interference coupling between the nanocavity resonance and Tamm plasmons. The spectral response depends on the nanocavity thickness, whose adjustment enables the generation of obvious Fano *** experiments agree well with the simulations. This work will open a new door for ultrathin cavities and applications of TI materials in light control and devices.

关键词： Bismuth Tellurium Refractive index Nanofilms Photonic crystals Transparency Silver Telecommunications Crystals Plasmons