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Complete kinetic model for esterification reaction of lauric acid with glycerol to synthesize glycerol monolaurate

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Chinese Journal of Chemical Engineering 2024年第6期70卷 211-221页

作者： Han-Qiao hu Yue Zhang ming Fan Yong Cai guang-Wen Chu Liang-Liang Zhang Research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Petrochemical Research Institute China National Petroleum CorporationBeijing 102206China

Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial *** direct esterification of glycerol with lauric acid is the main method to synthesize *** this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was *** isomerization reactions of GML and glycerol dilaurate were *** was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification *** kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.

关键词： Glycerol monolaurate p-Toluenesulfonic acid Esterification Kinetics Mass transfer

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： ming-Yang Yang Ji Yuan Xue-Lian Fu Jing-Jing Chen Jing hu Zhou-guang Lu Chen Liu guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

Current status and challenges of pig-to-human organ xenotransplantation

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Science China(Life Sciences) 2024年第4期67卷 829-831页

作者： minghui Fang Yong-guang Yang Zheng hu Key Laboratory of Organ Regeneration&Transplantation of Ministry of Education and National-Local Joint Engineering Laboratory of Animal Models for Human DiseasesThe First Hospital of Jilin UniversityChangchun 130061China

Organ shortage is a global *** collected by the Global Observatory on Donation and Transplantation reveals that over 150,000 solid organ transplants are conducted globally each year,a 52%increase from 2010(http://***/... 详细信息

关键词： globally global shortage

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A Novel Disturbance Observer Based Fixed-Time Sliding Mode Control for Robotic Manipulators With Global Fast Convergence

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 661-672页

作者： Dan Zhang Jiabin hu Jun Cheng Zheng-guang Wu huaicheng Yan IEEE Zhejiang University of Technology guangxi Normal University Zhejiang University the East China University of Science and Technology

This paper proposes a new global fixed-time sliding mode control strategy for the trajectory tracking control of uncertain robotic ***,a fixed-time disturbance observer(FTDO) is designed to deal with the adverse effects of model uncertainties and external disturbances in the manipulator *** an adaptive scheme is used and the adaptive FTDO(AFTDO) is developed,so that the priori knowledge of the lumped disturbance is not ***,a new non-singular fast terminal sliding mode(NFTSM) surface is designed by using an arctan function,which helps to overcome the singularity problem and enhance the robustness of the *** on the estimation of the lumped disturbance by the AFTDO,a fixed-time non-singular fast terminal sliding mode controller(FTNFTSMC)is developed to guarantee the trajectory tracking errors converge to zero within a fixed *** settling time is independent of the initial state of the *** addition,the stability of the AFTDO and FTNFTSMC is strictly proved by using Lyapunov ***,the fixed-time NFESM(FTNFTSM) algorithm is validated on a 2-link manipulator and comparisons with other existing sliding mode controllers(SMCs) are *** comparative results confirm that the FTNFTSMC has superior control performance.

关键词： Disturbance observer(DO) fixed-time non-singular sliding mode control robotic manipulator trajectory tracking

DLF-YOLOF:an improved YOLOF-based surface defect detection for steel plate

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Journal of Iron and Steel Research International 2024年第2期31卷 442-451页

作者： guang-hu Liu Mao-xiang Chu Rong-fen Gong Ze-hao Zheng School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan114051LiaoningChina

Surface defects can affect the quality of steel *** methods based on computer vision are currently applied to surface defect detection of steel ***,their real-time performance and object detection of small defect are still *** improved object detection network based on You Only Look One-level Feature(YOLOF)is proposed to show excellent performance in surface defect detection of steel plate,called ***,the anchor-free detector is used to reduce the network ***,deformable convolution network and local spatial attention module are introduced into the feature extraction network to increase the contextual information in the feature ***,the soft non-maximum suppression is used to improve detection accuracy ***,data augmentation is performed for small defect objects during training to improve detection *** show the average precision and average precision for small objects are 42.7%and 33.5%at a detection speed of 62 frames per second on a single GPU,*** shows that DLF-YOLOF has excellent performance to meet the needs of industrial real-time detection.

关键词： Steel surface defects detection YOLOF Anchor-free detector Small object detection Real-time detection

Enhancement of low-temperature toughness of Fe-Mn-C-Al alloy by rare earth Ce-modified inclusions

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Journal of Iron and Steel Research International 2024年第1期31卷 157-173页

作者： guang-kai Yang Chang-ling Zhuang Yi-zhuang Li Chen hu Shao-bo Li College of Materials and Metallurgy Guizhou UniversityGuiyang550025GuizhouChina Department of Mechanical Engineering University of Hong KongHong Kong999077China The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819LiaoningChina State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025GuizhouChina

Fe-Mn-C-Al alloys have been recognized as promising materials for certain low-temperature applications due to their exceptional mechanical properties and ***,their limited low-temperature toughness restricts their large-scale applications in specific *** influence of trace amounts of rare earth cerium(Ce)on the low-temperature toughness of Fe-18Mn-0.6C-1.8Al alloys was *** addition of Ce effectively alters the inclu-sions in the alloy,transforming large-sized irregular inclusions into fine ellipsoidal rare earth *** leads to a significant reduction in both the proportion and average size of the inclusions,resulting in their effective dispersion throughout the matrix and improved cryogenic *** presence of Ce-containing inclusions within the matrix reduces stress concentration,thereby inhibiting microcrack formation and improving impact absorption ***-cally,the addition of rare earth Ce alters the fracture behavior of the material at room temperature and low temperature,changing from brittle cleavage fracture to a more ductile failure *** impact toughness of the Fe-Mn-C-Al alloy is significantly improved by the addition of 0.0048 wt.%Ce,particularly at-196℃where the impact toughness reaches 103.6 J/cm^(2),representing an impressive improvement of 87.3%.

关键词： Fe-Mn-C-Al alloy Rare earth Low-temperature toughness Inclusion Fracture

Small molecule deoxynyboquinone triggers alkylation and ubiquitination of Keap1 at Cys489 on Kelch domain for Nrf2 activation and inflammatory therapy

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Journal of Pharmaceutical Analysis 2024年第3期14卷 401-415页

作者： Ke-Gang Linghu Tian Zhang guang-Tao Zhang Peng Lv Wen-Jun Zhang Guan-Ding Zhao Shi-Hang Xiong Qiu-Shuo Ma ming-ming Zhao Meiwan Chen Yuan-Jia hu Chang-Sheng Zhang hua Yu State Key Laboratory of Quality Research in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoMacao SARChina Macao Centre for Research and Development in Chinese Medicine Institute of Chinese Medical SciencesUniversity of MacaoMacao SARChina Key Laboratory of Tropical Marine Bio-resources and Ecology Guangdong Key Laboratory of Marine Materia MedicaRNAM Center for Marine MicrobiologySouth China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China State Key Laboratory of Functions and Applications of Medicinal Plants&School of Pharmaceutical Sciences Guizhou Medical UniversityGuiyang550025China

Activation of nuclear factor erythroid 2-related factor 2(Nrf2)by Kelch-like ECH-associated protein 1(Keap1)alkylation plays a central role in anti-inflammatory ***,activators of Nrf2 through alkylation of Keap1-Kelch domain have not been ***(DNQ)is a natural small molecule discovered from marine *** current study was designed to investigate the anti-inflammatory effects and molecular mechanisms of DNQ via alkylation of *** exhibited significant anti-inflammatory properties both in vitro and in *** pharmacophore responsible for the anti-inflammatory properties of DNQ was determined to be theα,β-unsaturated amides moieties by a chemical reaction between DNQ and *** exerted anti-inflammatory effects through activation of Nrf2/ARE ***1 was demonstrated to be the direct target of DNQ and bound with DNQ through conjugate addition reaction involving *** specific alkylation site of DNQ on Keap1 for Nrf2 activation was elucidated with a synthesized probe in conjunction with liquid chromatography-tandem mass *** triggered the ubiquitination and subsequent degradation of Keap1 by alkylation of the cysteine residue 489(Cys489)on Keap1-Kelch domain,ultimately enabling the activation of *** findings revealed that DNQ exhibited potent anti-inflammatory capacity throughα,β-unsaturated amides moieties active group which specifically activated Nrf2 signal pathway via alkylation/ubiquitination of Keap1-Kelch domain,suggesting the potential values of targeting Cys489 on Keap1-Kelch domain by DNQ-like small molecules in inflammatory therapies.

关键词： Deoxynyboquinone Anti-inflammation Target Keap1/Nrf2 Alkylation Ubiquitination

Role of flood discharge in shaping stream geometry:Analysis of a small modern stream in the Uinta Basin,USA

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Journal of Palaeogeography 2017年第1期6卷 84-95页

作者： guang-ming hu Ru-Xin Ding Yan-Bing Li Jing-Fu Shan Xiao-Tao Yu Wei Feng School of Geosciences Yangtze UniversityWuhan 430100HubeiChina State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China School of Earth Science and Geological Engineering Sun Yat-sen UniversityGuangzhou 510275GuangdongChina guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes Guangzhou 510275GuangdongChina The Third Production Plant Daqing Oilfield BranchPetroChinaDaqing 163000HeilongjiangChina

This small modern river system is located on a retativety flat （about 1°-2°）, unconsotidated sandy pediment surface in the Uinta Basin of Utah, USA, and it is with a scare of about 30 m tong and 0.4-0.8 m wide, simitar as a natural flume experiment modet. The smart stream is informatty divided into upstream, midstream and downstream. The anatysis shows that flood discharge influences channet sinuosity and morphology to produce an initiat meandering pattern which is tater changed to a braided and then a straisht pattern in the downflow direction. The upstream segment has a hish sinuous geometry dominated by both erosion （cutbanks） and deposition （point bars）. In the resistance of sporadic vegetation rooting in banks, the upstream flood deviates its original direction, which resutts in the powerful flood intensively eroding the cutbank and accreting clastics to build point bars, and thus producing a high sinuous channet. The midstream is dominated by deposits （many smart bars） with a moderate to tow sinuosity. Due to the bad drainage of the high sinuous channel in the upstream, the strong flood can cut off the point bar comptetely or even surmount the tevee in the fast meandering upstream, which widens the channel suddenty with a quick decreasing current power. Then, the ctastics from the upstream are untoaded in the midstream and form many smart bars. Untoaded sediments protect the bank, and the tow-power current brings a moderate erosion to the bank, which forms a moderate to tow sinuous channel in the midstream. The downstream shows multistage erosionat terraces in its retativety straight channets. After the midstream water drops its toad, it becomes ＂dear＂ and reaches downstream, the tower current power is hetptess to reform channet 8eometry. Thus, the downstream channel sesment keeps a tower sinuous geometry, evenstraight partially. Small amounts of fine clastics are deposited, and simultaneously multistage terraces are formed due to regressive flood erosion.

关键词： Sinuosity Braiding Point bar Channel bar Flood discharge Uinta Basin

Designing Symmetric Gradient Honeycomb Structures with Carbon‑Coated Iron‑Based Composites for High‑Efficiency Microwave Absorption

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Nano-Micro Letters 2024年第11期16卷 224-241页

作者： Yu Zhang Shu‑Hao Yang Yue Xin Bo Cai Peng‑Fei hu Hai‑Yang Dai Chen‑ming Liang Yun‑Tong Meng Ji‑Hao Su Xiao‑Juan Zhang Min Lu guang‑Sheng Wang School of Chemistry Beihang UniversityBeijing 100191People’s Republic of China School of Electronics and Information Zhengzhou University of Light IndustryZhengzhou 450002People’s Republic of China School of Chemical Engineering Northeast Electric Power UniversityJilin 132000People’s Republic of China College of Chemistry and Materials Engineering Beijing Technology and Business UniversityBeijing 100048People’s Republic of China

The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)*** this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based *** the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA *** MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 *** research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.

关键词： MIL-88C(Fe) Fe/Fe_(3)O_(4)/Fe_(3)C@C Controllable preparation Symmetric gradient honeycomb structure Microwave absorbing