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Benzenesulfonic acid-grafted UIO-66 with improved hydrophobicity as a stable Brønsted acid catalyst

Frontiers of Chemical Science and Engineering 2023年第10期17卷 1389-1398页

作者： Zongliang Kou Guanlun Sun Qiuyan Ding Hong Li xin Gao Xiaolei Fan Xiaoxia ou Qinhe Pan School of Chemical Engineering and Technology National Engineering Research Center of Distillation TechnologyCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Tianjin UniversityTianjin 300072China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Department of Chemical Engineering School of EngineeringThe University of ManchesterManchester M139PLUK Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315100China Key Laboratory of Ministry of Education for Advanced Materials in Tropical Island Resources School of Chemical Engineering and TechnologyHainan UniversityHaikou 570228China

Hydrothermal and catalytic stability of UIO-66 MOFs with defective structures are critical aspects to be considered in their catalytic applications,especially under the conditions involving water,moisture and/or ***,we report a facile strategy to introduce the macromolecular acid group to UIO-66 to improve the stability of the resulting UIO-66−PhSO3H MOF in aqueous phase *** detail,UIO-66−PhSO3H was obtained by grafting benzenesulfonic acid on the surface of the pristine UIO-66 to introduce the hydrophobicity,as well as the Brønsted acidity,then assessed using catalytic hydrolysis of cyclohexyl acetate(to cyclohexanol)in *** introduction of hydrophobic molecules to UIO-66 could prevent the material from being attacked by hydroxyl polar molecules effectively,explaining its good structural stability during ***-66−PhSO3H promoted the conversion of cyclohexyl acetate at ca.87%,and its activity and textural properties were basically intact after the cyclic stability *** facile modification strategy can improve the hydrothermal stability of UIO-66 significantly,which can expand its catalytic applications in aqueous systems.

关键词： metal−organic frameworks(MOFs) UIO-66 hydrolysis of cyclohexyl acetate hydrophobicity Brønsted acidity

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Effect of quenching-partitioning treatment on the microstructure, mechanical and abrasive properties of high carbon steel

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International Journal of Minerals,Metallurgy and Materials 2021年第4期28卷 676-687页

作者： Jian-ping Lai Jia-xin yu Jiong Wang Key Laboratory of Testing Technology for Manufacturing Process in Ministry of Education Mianyang 621010China School of Manufacturing Science and Engineering Southwest University of Science and TechnologyMianyang 621010China Central Sichuan Oil-Gas District Petro-China Southwest Oil and Gas Field CompanySuining 629000China

The present work employed the X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, and electron probe microanalysis techniques to identify the microstructural evolution and mechanical and abrasive behavior of high carbon steel during quenching-partitioning treatment with an aim to enhance the toughness and wear resistance of high carbon *** showed that, with the increase in partitioning temperature from 250 to 400℃, the amount of retained austenite(RA) decreased resulting from the carbide precipitation effect after longer partitioning ***, the stability of RA generally increased because of the enhanced degree of carbon enrichment in *** the factors affecting the toughness of high carbon steel, the stability of RA associated with size, carbon content, and morphology plays a significant role in determining the toughness of high carbon *** analysis of the wear resistance of samples with different mechanical properties shows that hardness is the primary factor affecting the wear resistance of high carbon steel, and the toughness is the secondary one.

关键词： high carbon steel quenching and partitioning microstructural evolution retained austenite

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Conflict Analysis and Detection Based on Model Checking for Spatial Access Control Policy

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Tsinghua Science and Technology 2017年第5期22卷 478-488页

作者： Aijuan Zhang Cheng Ji yu Bao xin Li the School of Computer Science and Technology China University of Mining and TechnologyXuzhou 221116China the Schoo1 of Environment Science and Spatial Inform atics China University of M ining and TechnologyXuzhou 221116China

In this paper, we propose a Multi-granularity Spatial Access Control （MSAC） model, in which multi- granularity spatial objects introduce more types of policy rule conflicts than single-granularity objects do. To analyze and detect these conflicts, we first analyze the conflict types with respect to the relationship among the policy rules, and then formalize the conflicts by template matrices. We designed a model-checking algorithm to detect potential conflicts by establishing formalized matrices of the policy set. Lastly, we conducted experiments to verify the performance of the algorithm using various spatial data sets and rule sets. The results show that the algorithm can detect all the formalized conflicts. Moreover, the algorithm＇s efficiency is more influenced by the spatial object granularity than the size of the rule set.

关键词： spatial object multi-granularity conflict detection model-checking

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Modular Verification of SPARCv8 Code

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Journal of Computer Science & Technology 2020年第6期35卷 1382-1405页

作者： Jun-Peng Zha xin-yu Feng Lei Qiao Department of Computer Science and Technology Nanjing UniversityNanjing 210023China State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China Beijing Institute of Control Engineering Beijing 100080China

Inline assembly code is common in system software to interact with the underlying hardware platforms. The safety and correctness of the assembly code is crucial to guarantee the safety of the whole system. In this paper, we propose a practical Hoare-style program logic for verifying SPARC (Scalable Processor Architecture) assembly code. The logic supports modular reasoning about the main features of SPARCv8 ISA (instruction set architecture), including delayed control transfers, delayed writes to special registers, and register windows. It also supports relational reasoning for refinement verification. We have applied it to verify that there is a contextual refinement between a context switch routine in SPARCv8 and a switch primitive. The program logic and its soundness proof have been mechanized in Coq.

关键词： Scalable Processor Architecture Version 8(SPARCv8) assembly code verification context switch Coq refinement verification

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Nonlinear metamaterial enabled aeroelastic vibration reduction of a supersonic cantilever wing plate

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Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1749-1772页

作者： Peng SHENG xin FANG Dianlong yu Jihong WEN Laboratory of Science and Technology on Integrated Logistics Support College of Intelligence Science and TechnologyNational University of Defense TechnologyChangsha 410073China

The violent vibration of supersonic wings threatens aircraft *** paper proposes the strongly nonlinear acoustic metamaterial(NAM)method to mitigate aeroelastic vibration in supersonic wing *** employ the cantilever plate to simulate the practical behavior of a *** aeroelastic vibration model of the NAM cantilever plate is established based on the mode superposition method and a modified third-order piston *** aerodynamic properties are systematically studied using both the timedomain integration and frequency-domain harmonic balance *** presenting the flutter and post-flutter behaviors of the NAM wing,we emphasize more on the preflutter broadband vibration that is prevalent in *** results show that the NAM method can reduce the low-frequency and broadband pre-flutter steady vibration by 50%-90%,while the post-flutter vibration is reduced by over 95%,and the critical flutter velocity is also slightly *** clarified,the significant reduction arises from the bandgap,chaotic band,and nonlinear resonances of the NAM *** reduction effect is robust across a broad range of parameters,with optimal performance achieved with only 10%attached *** work offers a novel approach for reducing aeroelastic vibration in aircraft,and it expands the study of nonlinear acoustic/elastic metamaterials.

关键词： nonlinear acoustic metamaterial(NAM) hypersonic aeroelastic vibration vibration reduction fluid-structure interaction

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Using BiLSTM with attention mechanism to automatically detect self-admitted technical debt

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Frontiers of Computer Science 2021年第4期15卷 49-60页

作者： Dongjin yu Lin WANG xin CHEN Jie CHEN School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou 310018China

Technical debt is a metaphor for seeking short-term gains at expense of long-term code *** studies have shown that self-admitted technical debt,which is introduced intentionally,has strong negative impacts on software development and incurs high maintenance *** help developers identify self-admitted technical debt,researchers have proposed many state-of-the-art ***,there is still room for improvement about the effectiveness of the current methods,as self-admitted technical debt comments have the characteristics of length variability,low proportion and style ***,in this paper,we propose a novel approach based on the bidirectional long short-term memory(BiLSTM)networks with the attention mechanism to automatically detect self-admitted technical debt by leveraging source code *** BiLSTM,we utilize a balanced cross entropy loss function to overcome the class unbalance *** experimentally investigate the performance of our approach on a public dataset including 62,566 code comments from ten open source *** results show that our approach achieves 81.75%in terms of precision,72.24%in terms of recall and 75.86%in terms of F1-score on average and outperforms the state-of-the-art text mining-based method by 8.14%,5.49%and 6.64%,respectively.

关键词： technical debt self-admitted technical debt long short-term memory attention mechanism natural language processing

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Highly selective electrosynthesis of 3,4-dihydroisoquinoline accompanied with hydrogen production over three-dimensional hollow CoNi-based microarray electrocatalysts

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Nano Research 2024年第4期17卷 2509-2519页

作者： yu xin Liyu Chen Yingwei Li Kui Shen Guangdong Provincial Key Lab for Green Chemical Product Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Electrocatalytic oxidation reaction of biomass-based derivatives is an excellent candidate to replace water oxidation for obtaining both value-added products and hydrogen(H_(2)),but the exploration of competent electrocatalysts is still highly ***,two new types of three-dimensional self-supported hollow microarrays containing CoNi layered double hydroxide(CoNi-LDH)and N-doped carbon nanosheets decorated with CoNi alloyed nanoparticles(CoNi-NC)on carbon cloth(CC)are prepared,which are further used as efficient electrocatalysts for tetrahydroisoquinoline(THIQ)electrooxidation and hydrogen evolution reaction(HER),*** demonstrate that the Co-modulated electronic environment for Ni(II)/Ni(Ⅲ)redox-looping in CoNi-LDH is the main factor to boost the selectivity of 3,4-dihydroisoquinoline(DHIQ)for the indirect electrooxidation process of *** functional theory(DFT)calculations reveal that the Ni(Ⅲ)/Co(Ⅲ)dual sites of CoNi-LDH exhibit enhanced adsorption for THIQ but poorer adsorption for DHIQ compared to pure Co(Ⅲ)or Ni(Ⅲ).Therefore,the Ni(Ⅲ)/Co(Ⅲ)dual sites can effectively inhibit the peroxidation of DHIQ to isoquinoline(IQ)over CoNi-LDH,thus improving the selectivity of DHIQ to nearly 100%,much higher than that of its pure Ni ***,CC@CoNi-NC can deliver high HER activity with low overpotential(40 mV@10 mA·cm^(-2))and high exchange current density(3.08 mA·cm^(-2)).Impressively,the assembled flow-cell device with CC@CoNi-LDH anode and CC@CoNi-NC cathode only requires low cell voltage and electricity consumption of 1.6 V and 3.50 kWh per cubic meter of H_(2)(@25 mA·cm^(-2)).

关键词： highly selective electrosynthesis dihydroisoquinolines hydrogen evolution reaction metal-organic frameworks hollow microarrays

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Bimetallic anchoring catalysis for C–H and C–C activation

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Science China Chemistry 2021年第11期64卷 1923-1937页

作者： Jiang-Fei Li yu-xin Luan Mengchun Ye State Key Laboratory and Institute of Elemento-Organic Chemistry College of ChemistryFrontiers Science Center for New Organic MatterNankai UniversityTianjin300071China

Following the age of directing group,anchoring catalysis starts coming to the center of the *** from the directinggroup strategy that needs a preinstalled directing group in substrates,anchoring catalysis relies on a reversible interaction between a substrate and a catalyst,which then directs metal to activate inert chemical *** reversible directing effect not only generates good site-and stereo-selectivity as traditional directing groups do but also eliminates the requirement of stoichiometric amounts of directing *** variously reported anchoring catalysis,coordinative bimetallic anchoring catalysis in general displays superior reactivity than others because coordinative bonding not only affords strong interaction of catalysts with substrates but also displays good compatibility with substrates and reaction *** recent years,big progress has been achieved for coordinative bimetallic anchoring *** review gave a detailed summary of this field,including catalyst development,catalyst types,reaction types and reaction mechanisms.

关键词： C–H activation C–C activation bimetallic catalysis enantioselective anchoring catalysis

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Numerical study of the influence of the atmospheric pressure on the thermal environment in the passenger cabin

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Building Simulation 2024年第2期17卷 253-265页

作者： xin Su yu Guo Zhengwei Long Yi Cao Tianjin Key Lab.of Indoor Air Environmental Quality Control School of Environmental Science and EngineeringTianjin UniversityTianjin300072China Shanghai Aircraft Design and Research Institute Jinke RoadPudong DistrictShanghai201210China

The cabin air pressure remains lower than the horizontal atmospheric pressure when the airplane is in *** pressure is one of the parameters that must be taken into consideration while studying the thermal environment of an airplane *** are still no reference values for aircraft cabins despite the fact that numerous studies on low pressure heat transfer have demonstrated the connection between convective heat transfer coefficient(CHTC)and air *** this paper,a correction method for CHTC under low pressure conditions was established by using the dummy heat dissipation in the low-pressure cabin *** this basis,a thermal environment simulation model was developed,then was applied to the simulation of a seven-row aircraft cabin containing 42 passengers,and the CHTC and heat loss of dummy surface in the cabin were ***,the results of PMV calculated by using heat dissipation and air parameters at sampling points were *** results show that the modified CHTC can accurately reflect the cabin thermal environment under low pressure conditions,and the correction of CHTC can be realized by adjusting the turbulent Prandtl number,which is nonlinear correlated with the *** simulation results of the thermal environment in the seven-row cabin show that the CHTC changes by about 42%before and after *** air pressure decreases during take-off,which reduces the average CHTC of the crew surface from 5.09 W/(m^(2)·K)to 4.56 W/(m^(2)·K),but the air temperature rises by about 0.2°C as a *** deviation of PMV results calculated by using simulated heat loss data and using air parameters of measuring points in space is up to 0.5,but the latter is representative for calculating the thermal comfort level of the whole cabin.

关键词： low pressure aircraft cabin simulation heat dissipation convective heat transfer coefficient

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A high mobility C_(60) field-effect transistor with an ultrathin pentacene passivation layer and bathophenanthroline/metal bilayer electrodes

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Chinese Physics B 2012年第2期21卷 498-503页

作者： Zhou Jian-Lin yu Jun-Sheng yu xin-Ge Cai xin-Yang State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic InformationUniversity of Electronic Science and Technology of ChinaChengdu 610054China Department of Electronic Engineering College of Communication and ElectronicsChongqing UniversityChongqing 400044China

C60 field-effect transistor （OFET） with a mobility as high as 5.17 cm2/V.s is fabricated. In our experiment, an ultrathin pentacene passivation layer on poly-（methyl methacrylate）（PMMA） insulator and a bathophenanthroline （Bphen）/Ag bilayer electrode are prepared. The OFET shows a significant enhancement of electron mobility compared with the corresponding device with a single PMMA insultor and an Ag electrode. By analysing the C60 film with atomic force microscopy and X-ray diffraction techniques, it is shown that the pentacene passivation layer can contribute to C60 film growth with the large grain size and significantly improve crystallinity. Moreover, the Bphen buffer layer can reduce the electron contact barrier from Ag electrodes to C60 film efficiently.

关键词： organic field-effect transistors C60 Bphen passivation layer

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