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Fabrication of NiZn bimetallic oxides catalysts supported on carbon black waste for catalytic pyrolysis of fatty acid

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APPLIED CATALYSIS A-GENERAL 2023年 668卷

作者： zhang, Yang zhang, xuwen Guo, Fangsong Tan, Kok Bing Wang, Youting Sun, Kang Rao, Xiaoping zhang, Xiaodong Zhan, Guowu Huaqiao Univ Acad Adv Carbon Convers Technol Coll Chem Engn Fujian Prov Key Lab Biomass Low Carbon Convers 668 Jimei Ave Xiamen 361021 Fujian Peoples R China Jimei Univ Coll Marine Equipment & Mech Engn 185 Yinjiang Rd Xiamen 361021 Fujian Peoples R China Chinese Acad Forestry CAF Inst Chem Ind Forest Prod 16 Suojin F Village Nanjing 210042 Jiangsu Peoples R China

Herein, NiZn bimetallic oxides derived from calcination treatment of metal-organic frameworks (MOFs) were successfully loaded onto the carbon black waste as support obtained from the oil refinery. The resulting hybrids could serve as environmentally friendly and cost-effective catalysts for the deoxygenation of biomass-derived fatty acids under an inert atmosphere. An online pyrolysis-gas chromatography/mass spectrometry (Py-GC/ MS) system was employed to evaluate their deoxygenation performance. The optimized catalysts demonstrated remarkably high stearic acid conversion of 99.6% and selectivity towards C8-C17 olefins of 57.2%. Furthermore, these catalysts with varying metal loadings also exhibited excellent efficiency in deoxygenation reactions of other types of fatty acids, such as myristic acid and palmitic acid, achieving conversion exceeding 85% and selectivities towards olefins of ca. 50%. When converting coconut oil, the supported NiZn bimetallic oxides showed excellent selectivity towards olefins (>60%). Furthermore, in-situ DRIFTS results suggest that fatty alcohols might be the key intermediates in the deoxidation reactions of fatty acid. This study not only demonstrates the great potential for obtaining valuable chemicals from biomass but also provides some insights into the fabrication of catalyst materials by using industrial solid waste.

关键词： Carbonaceous residue Metal oxide Stearic acid Deoxygenation reaction Resource utilization Olefin

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Direct Arylation Polycondensation-Derived Polythiophene Achieves Over 16% Efficiency in Binary Organic Solar Cells via Tuning Aggregation and Miscibility

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ADVANCED ENERGY MATERIALS 2024年第47期14卷

作者： zhang, xuwen zhang, Tao Liang, Ziqi Shi, Yibo Li, Saimeng Xu, Chenhui Li, Miaomiao Ye, Long Hou, Jianhui Geng, Yanhou Tianjin Univ Sch Mat Sci & Engn Tianjin Key Lab Mol Optoelect SciKey Lab Organ In Minist EducCollaborat Innovat Ctr Chem Sci & Engn Tianjin 300350 Peoples R China Chinese Acad Sci Inst Chem CAS Res Educ Ctr Excellence Mol Sci State Key Lab Polymer Phys & ChemBeijing Natl Lab Beijing 100190 Peoples R China

Polythiophenes are the most appealing donor materials in organic solar cells (OSCs) due to their simple chemical structures. However, the top-performance polythiophenes are typically synthesized via Stille polycondensation, which is problematic due to significant toxicity and poor atom economy. By contrast, direct arylation polycondensation (DArP) is an eco-friendly, and atom-efficient alternative for synthesizing conjugated polymers, while the best efficiency for DArP-derived polythiophenes is below 12%. This study reports a series of polythiophene-based donors synthesized via DArP. Among these, PT4F-Th reaches a power conversion efficiency (PCE) of 16.4%, which not only matches the current record for polythiophene-based donor materials, but also marks the highest PCE achieved by DArP-derived donors to date. The superior performance of PT4F-Th is largely attributed to its optimal temperature-dependent aggregation behavior and moderate miscibility with acceptors, along with the highest crystallinity among the candidates, resulting in the most favorable blend film morphology. This study underscores the significant potential of DArP-derived polythiophenes in developing high-performance and eco-friendly OSCs. A series of polythiophene-based donors are synthesized using direct arylation polycondensation (DArP), highlighting PT4F-Th, which achieves an outstanding power conversion efficiency (PCE) of 16.4% in binary organic solar cells (OSCs). This efficiency sets a new record for DArP-derived donors. Blend film morphology is characterized by X-ray scattering and microscopy, emphasizing the synergistic effects of temperature-dependent aggregation behavior and miscibility. image

关键词： direct arylation polycondensation miscibility organic solar cells polythiophene power conversion efficiency

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A HEINTZE-KARCHER TYPE INEQUALITY FOR HYPERSURFACES WITH CAPILLARY BOUNDARY

arXiv

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arXiv 2022年

作者： Jia, Xiaohan Xia, Chao zhang, xuwen School of Mathematical Sciences Xiamen University Xiamen361005 China

In this paper, we establish a Heintze-Karcher type inequality for hypersurfaces with capillary boundary of contact angle θ ∈ (0, π/2) in a half space or a half ball, by using solution to a mixed boundary value problem in Reilly type formula. Consequently, we give a new proof of Alexandrov type theorem for embedded capillary constant mean curvature hypersurfaces with contact angle θ ∈ (0, π/2) in a half space or a half *** Codes 53C24, 35J25, 53C21 Copyright © 2022, The Authors. All rights reserved.

关键词： Contact angle

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Conjugated Polymers from Direct Arylation Polycondensation of 3,4-Difluorothiophene-Substituted Aryls: Synthesis and Properties

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MACROMOLECULAR RAPID COMMUNICATIONS 2023年第23期44卷 e2300393-e2300393页

作者： Sui, Ying zhang, xuwen Xu, Chenhui Shi, Yibo Deng, Yunfeng Han, Yang Geng, Yanhou Tianjin Chengjian Univ Sch Mat Sci & Engn Tianjin 300384 Peoples R China Tianjin Univ Sch Mat Sci & Engn Tianjin 300072 Peoples R China Tianjin Univ Collaborat Innovat Ctr Chem Sci & Engn Tianjin Tianjin Key Lab Mol Optoelect Sci Tianjin 300072 Peoples R China

3,4-Difluorothiophene-substituted aryls, i.e., 1,4-bis(3,4-difluorothiophen-2-yl)-benzene (Ph-2FTh), 1,4-bis(3,4-difluorothiophen-2-yl)-2,5-difluorobenzene (2FPh-2FTh), and 4,7-bis(3,4-difluorothiophen-2-yl)-2,1,3-benzothiadiazole (BTz-2FTh), are synthesized as CH monomers for the synthesis of conjugated polymers (CPs) via direct arylation polycondensation (DArP) with diketopyrrolopyrrole (DPP) and isoindigo (IID) derivatives as CBr monomers. The Gibbs free energies of activation for direct arylation (& UDelta;G298 K, kcal mol-1) for & alpha;CH bonds of thiophene moieties as calculated by density functional theory (DFT) are 14.3, 16.5, and 16.4 kcal mol-1 for Ph-2FTh, 2FPh-2FTh and BTz-2FTh, respectively, meaning that inserting an electron-deficient unit in 3,3 & PRIME;,4,4 & PRIME;-tetrafluoro-2,2 & PRIME;-bithiophene (4FBT, & UDelta;G298K: 14.6 kcal mol-1) may cause a reactivity decrease of the CH monomers. Photophysical and semiconducting properties of the resulting six CPs (i.e., DPP-Ph, DPP-2FPh, DPP-BTz, 2FIID-Ph, 2FIID-2FPh, and 2FIID-BTz) are characterized in detail. DPP-based CPs show ambipolar transport properties while IID-based ones exhibited n-type behavior owing to the deeper frontier molecular orbital energy levels of IID-based CPs. With source/drain electrodes modified with polyethylenimine ethoxylated, n-channel organic thin-film transistors with maximum electron mobility of 0.40, 0.54, 0.29, 0.05, 0.16, and 0.01 cm2 V-1 s-1 for DPP-Ph, DPP-2FPh, DPP-BTz, 2FIID-Ph, 2FIID-2FPh, and 2FIID-BTz, respectively, are fabricated. DPP-2FPh exhibits the best device performance due to the good film morphology and the highest intermolecular packing order. Three CH monomers Ph-2FTh, 2FPh-2FTh, and BTz-2FTh with 3,4-difluorothiophene as terminal units and phenyl, 2,5-difluorophenyl and benzothiadiazole as central units are synthesized for direct arylation polycondensation to diketopyrrolopyrrole- and isoindigo-based high-mobility conjugated polymers. n-Channel org

关键词： conjugated polymers direct arylation polycondensation organic thin-film transistors polymer semiconductors

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Crystalline 1D Linear Conjugated Polymers with a Quinoidal Unit As Metal-Free Electrocatalysts for Oxygen Reduction

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ADVANCED ENERGY MATERIALS 2024年第44期14卷

作者： Fan, Renzhen Wang, Cheng zhang, Xiaofei zhang, xuwen Dong, Weijia Xu, Yiyang Xu, Chenhui Chi, Chunyan Zhu, Jun Deng, Yunfeng Geng, Yanhou Tianjin Univ Joint Sch Natl Univ Singapore & Tianjin Univ Int Campus Binhai New City 350207 Fuzhou Peoples R China Tianjin Univ Sch Mat Sci & Engn Tianjin 300072 Peoples R China Tianjin Univ Tianjin Key Lab Mol Optoelect Sci Tianjin 300072 Peoples R China Collaborat Innovat Ctr Chem Sci & Engn Tianjin Tianjin 300072 Peoples R China Agcy Sci Tech & Res A STAR Inst Mat Res & Engn IMRE 2 Fusionopolis Way Singapore 138634 Singapore Natl Univ Singapore Dept Chem 3 Sci Dr 3 Singapore 117543 Singapore

Crystalline and soluble 1D linear conjugated polymers (LCPs) have garnered considerable interest as cost-effective and efficient metal-free electrocatalysts for the oxygen reduction reaction (ORR) due to their high exposure of catalytic sites and ease of processing. However, difficulties remain in achieving excellent ORR performance for 1D LCPs by conventional molecular design. Herein, it is demonstrated the utilization of quinoidal units as a promising strategy to develop 1D LCPs for ORR. The incorporation of quinoidal unit not only results in polymers with strong inter- and intra-molecular interactions and low-lying LUMO (lowest unoccupied molecular orbital) energy levels, but also provides polymers with good crystallinity and commendable charge carrier mobilities. The electronic properties of these polymers are fine-tuned through the introduction of additional heteroatoms and/or substituents in the monomers and comonomers to understand and optimize their ORR catalytic activity. Evaluation of their catalytic performances reveals a remarkable half-wave potential and limiting current density of up to 0.74 V (vs reversible hydrogen electrod) and 7.50 mA cm-2, respectively. Notably, these performances are achieved without the addition of carbon nanomaterials as support. This study offers a new insight into the design of highly efficient metal-free organic electrocatalysts. 1D linear conjugated polymers containing a quinoidal unit are synthesized as the metal-free electrocatalysts for oxygen reduction reaction. These polymers show good film-forming properties, well-ordered structures, and excellent charge transport abilities. As a result, they exhibit high oxygen reduction reaction catalytic activities without the need for carbon nanomaterials as support. image

关键词： conjugated polymers energy conversion metal-free oxygen reduction reaction quinoidal compounds

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Selective and Coverage Multi-head Attention for Abstractive Summarization 2

Selective and Coverage Multi-head Attention for Abstractive ...

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2019 2nd International Conference on Computer Information Science and Artificial Intelligence, CISAI 2019

作者： zhang, xuwen Liu, Gongshen School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai200240 China

Although the Transformer model has outperformed traditional sequence-To-sequence model in a variety of natural language processing (NLP) tasks, it still suffers from semantic irrelevance and repetition for abstractive text summarization. The main reason is that the long text to be summarized is usually composed of multi-sentences and has much redundant information. To tackle this problem, we propose a selective and coverage multi-head attention framework based on the original Transformer. It contains a Convolutional Neural Network (CNN) selective gate, which combines n-gram features with whole semantic representation to obtain core information from the long input sentence. Besides, we use a coverage mechanism in the multi-head attention to keep track of the words which have been summarized. The evaluations on Chinese and English text summarization datasets both demonstrate that the proposed selective and coverage multi-head attention model outperforms the baseline models by 4.6 and 0.3 ROUGE-2 points respectively. And the analysis shows that the proposed model generates the summary with higher quality and less repetition. © Published under licence by IOP Publishing Ltd.

关键词： Semantics

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HEINTZE-KARCHER INEQUALITY AND CAPILLARY HYPERSURFACES IN A WEDGE

arXiv

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arXiv 2022年

作者： Jia, Xiaohan Wang, Guofang Xia, Chao zhang, xuwen School of Mathematics Southeast University Nanjing211189 China Mathematisches Institut Universität Freiburg Ernst-Zermelo-Str.1 Freiburg79104 Germany School of Mathematical Sciences Xiamen University Xiamen361005 China

In this paper, we utilize the method of Heintze-Karcher to prove a "best" version of Heintze-Karcher-type inequality for capillary hypersurfaces in the half-space or in a wedge. One of new crucial ingredients in the proof is modified parallel hypersurfaces which are very natural to be used to study capillary hypersurfaces. A more technical part is a subtle analysis along the edge of a wedge. As an application, we classify completely embedded capillary constant mean curvature hypersurfaces that hit the edge in a wedge, which is a subtler *** Codes 53C24, 35J25, 53C21 Copyright © 2022, The Authors. All rights reserved.

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A Two-level Learning Approach for Achieving the Sustainable Development of Service Ecosystem

A Two-level Learning Approach for Achieving the Sustainable ...

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IEEE International Conference on Web Services (ICWS)

作者： Chao Peng Xiao Xue xuwen zhang Peilin Ji Yifan Shen Li Fang Zhiyong Feng College of Intelligence and Computing Tianjin University Tianjin China Tianjin Key Laboratory of Healthy Habitat and Smart Technology Tianjin China School of Information Xi’an University of Finance and Economics Xi’an China

ISBN: (数字)9798350368550

ISBN: (纸本)9798350368567

The governance of service ecosystem needs to balance efficiency and fairness to promote the sustainable development of the system, making it an important topic. However, service entities in the service ecosystem have autonomy and engage in dynamic game with governance strategies, leading to governance challenges. To address this issue, we model the governance process as a repeated sequential game between the governance algorithm and service entities, and propose a novel two-level learning algorithm. This algorithm considers the learning evolution of service entities and the co-evolutionary of the governance algorithm, using reinforcement learning to learn effective governance strategies while also considering the response function of service entities to balance efficiency and fairness. Combining the ideas of bilevel optimization and online learning, this algorithm effectively balances exploration (understanding the service entities’ responses function) and exploitation (choosing efficient actions). We apply the algorithm to a classic service ecosystem, the ride-hailing service system, and empirically demonstrate its effectiveness in the governance task of order dispatching.

关键词： Web services Heuristic algorithms Ecosystems Games Reinforcement learning Dispatching Robustness Sustainable development Optimization

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ALEXANDROV’S THEOREM FOR ANISOTROPIC CAPILLARY HYPERSURFACES IN THE HALF-SPACE

arXiv

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arXiv 2022年

作者： Jia, Xiaohan Wang, Guofang Xia, Chao zhang, xuwen School of Mathematical Sciences Xiamen University Xiamen361005 China Mathematisches Institut Universität Freiburg Ernst-Zermelo-Str.1 Freiburg79104 Germany

In this paper, we show that any embedded capillary hypersurface in the half-space with anisotropic constant mean curvature is a truncated Wulff shape. This extends Wente’s result [32] to the anisotropic case and He-Li-Ma-Ge’s result [15] to the capillary boundary case. The main ingredients in the proof are a new Heintze-Karcher inequality and a new Minkowski formula, which have their own *** Codes 53C24, 35J25, 53C21 Copyright © 2022, The Authors. All rights reserved.

关键词： Anisotropy

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寒区大温差环境下沥青混合料力学响应差异性分析

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江西建材 2024年第12期 382-384页

作者：孙梦张月张绪雯黑龙江科技大学建筑工程学院黑龙江哈尔滨150022

为了验证最佳配比下PU沥青混合料在寒区应用的优越性,文中利用ABAQUS软件,采用对比研究的方式,展开PU改性沥青混合料面层与普通沥青混合料面层的路面结构力学响应差异分析,结合寒区大温差特点设置了温度梯度变化,体现PU改性后具有减小... 详细信息

为了验证最佳配比下PU沥青混合料在寒区应用的优越性,文中利用ABAQUS软件,采用对比研究的方式,展开PU改性沥青混合料面层与普通沥青混合料面层的路面结构力学响应差异分析,结合寒区大温差特点设置了温度梯度变化,体现PU改性后具有减小应力应变受温度影响的作用。结果表明,整体抗压回弹模量得到了提升,其应力扩散效应也随之增强,从而使整体沥青路面结构的力学性能得到提升。

关键词：最佳配比 PU沥青混合料温度梯度

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