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Artemsieverolactones A—H,Eight Guaiane-Type Sesquiterpenoid Trimers from Artemisia sieversiana

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Chinese Journal of Chemistry 2024年第10期42卷 1084-1092页

作者： Wei Dong Xiao-yan Huang Tian-Ze Li yan-Mei Weng Chang-An Geng ji-Jun Chen State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunmingYunnan 650201China University of Chinese Academyof Sciences Beijing 100049China

Eight new guaiane-type sesquiterpenoid trimers,artemsieverolactones A—H,possessing unprecedented scaffolds via biocatalyzed[4+2]Diels−Alder cycloaddition reactions were identified from Artemisia *** structures were determined by comprehensive spectroscopic data,single-crystal X-ray diffraction analyses,and ECD *** terms of structure,artemsieverolactones A—H are first examples of sesquiterpenoid trimers from guaiane-type sesquiterpenoid through four different[4+2]Diels−Alder cycloaddition *** fibrosis assay suggested that five compounds exhibited activity against HSC-LX2 with IC_(50)values ranging from 37.8 to 117.1μmol/*** most active artemsieverolactone B(2)displayed significant inhibitory activity against HSC-LX2 with IC_(50)value of 37.8μmol/L,which was 3 times more active than the positive drug silybin(IC_(50),139.7μmol/L).Preliminary mechanism study revealed that artemsieverolactone B could inhibit the deposition of human collagen typeⅠ(ColⅠ),human hyaluronic acid(HA),and human laminin(HL)with IC_(50)values of 40.4μmol/L(Col I),55.1μmol/L(HL),47.3μmol/L(HA),which was 2 to 3-fold more potent than silybin.

关键词： Artemisia sieversiana Artemsieverolactones A-H Guaiane-type sesquiterpenoid trimers Antihepatic fibrosis Extracellular matrix Cancer NMR spectroscopy X-ray diffraction

Numerical Study on the Effect of Gap Diffraction on the Hydrodynamic Performance of A Floating Breakwater

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China Ocean Engineering 2024年第4期38卷 663-675页

作者： BIAN Xiang-qian ji Chun-yan XU Sheng GUO jian-ting HUO Fa-li School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring *** a reasonable gap between the flume wall and the FBs is a critical step in 2D flume ***,research on the effect of the gap on the accuracy of 2D FB experimental results is *** address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published *** is good agreement between them,indicating that the numerical model is sufficiently *** numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D *** was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.

关键词： floating breakwater diffraction effect gap hydrodynamic performance model experiments CFD numerical simulation

Retrieval of Antarctic sea ice freeboard and thickness from HY-2B satellite altimeter data

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Acta Oceanologica Sinica 2024年第3期43卷 87-101页

作者： Yizhuo Chen Xiaoping Pang qing ji Zhongnan yan Zeyu Liang Chenlei Zhang Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China Key Laboratory of Polar Surveying and Mapping Science Ministry of Natural ResourcesWuhan 430079China Key Laboratory of Polar Environment Monitoring and Public Governance Ministry of EducationWuhan 430079China 4 School of Geography and Tourism Anhui Normal UniversityWuhu 241002China

Antarctic sea ice is an important part of the Earth’s atmospheric system,and satellite remote sensing is an important technology for observing Antarctic sea *** Chinese Haiyang-2B(HY-2B)satellite altimeter data could be used to estimate sea ice freeboard and provide alternative Antarctic sea ice thickness information with a high precision and long time series,as other radar altimetry satellites can,needs further *** paper proposed an algorithm to discriminate leads and then retrieve sea ice freeboard and thickness from HY-2B radar altimeter *** first collected the Moderate-resolution Imaging Spectroradiometer ice surface temperature(IST)product from the National Aeronautics and Space Administration to extract leads from the Antarctic waters and verified their accuracy through Sentinel-1 Synthetic Aperture Radar ***,a surface classification decision tree was generated for HY-2B satellite altimeter measurements of the Antarctic waters to extract leads and calculate local sea surface *** then estimated the Antarctic sea ice freeboard and thickness based on local sea surface heights and the static equilibrium ***,the retrieved HY-2B Antarctic sea ice thickness was compared with the CryoSat-2 sea ice thickness and the Antarctic Sea Ice Processes and Climate(ASPeCt)ship-based observed sea ice *** results indicate that our classification decision tree constructed for HY-2B satellite altimeter measurements was reasonable,and the root mean square error of the obtained sea ice thickness compared to the ship measurements was 0.62 *** proposed sea ice thickness algorithm for the HY-2B radar satellite fills a gap in this application domain for the HY-series satellites and can be a complement to existing Antarctic sea ice thickness products;this algorithm could provide long-time-series and large-scale sea ice thickness data that contribute to research on global climate change.

关键词： HY-2B satellite altimeter classification decision tree sea ice freeboard and thickness Antarctic waters

A reweighted damped singular spectrum analysis method for robust seismic noise suppression

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Petroleum Science 2024年第3期21卷 1671-1682页

作者： Wei-Lin Huang yan-Xin Zhou yang Zhou Wei-jie Liu ji-Dong Li State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206China SINOPEC Geophysical Research Institute Nanjing211103jiangsuChina

(Multichannel)Singular spectrum analysis is considered as one of the most effective methods for seismic incoherent noise *** utilizes the low-rank feature of seismic signal and regards the noise suppression as a low-rank reconstruction ***,in some cases the seismic geophones receive some erratic disturbances and the amplitudes are dramatically larger than other *** presence of this kind of noise,called erratic noise,makes singular spectrum analysis(SSA)reconstruction unstable and has undesirable effects on the final *** robustify the low-rank reconstruction of seismic data by a reweighted damped SSA(RD-SSA)*** incorporates the damped SSA,an improved version of SSA,into a reweighted *** damping operator is used to weaken the artificial disturbance introduced by the low-rank projection of both erratic and random *** central idea of the RD-SSA method is to iteratively approximate the observed data with the quadratic norm for the first iteration and the Tukeys bisquare norm for the rest *** RD-SSA method can suppress seismic incoherent noise and keep the reconstruction process robust to the erratic *** feasibility of RD-SSA is validated via both synthetic and field data examples.

关键词： Singular spectrum analysis Damping operator Seismic erratic noise Seismic signal processing Robust low-rank reconstruction

Effect of Phase Separation Size on the Properties of Self-healing Elastomer

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Chinese Journal of Polymer Science 2024年第6期42卷 798-804页

作者： Jun Xu Lei Zhu Xian-qi Feng Cong Sui Wen-Peng Zhao Shou-Ke yan School of Chemical Engineering Qingdao University of Science&TechnologyQingdao266042China College of Engineering Yanching institute of TechnologyLangfang065210China Key Laboratory of Rubber-plastics Qingdao University of Science&TechnologyQingdao266042China State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China

Regulation of phase structure has been recognized as one of the most effective ways to fabricate self-healing polymers with high mechanical *** mechanical properties of the resultant polymers are certainly affected by the size of separated phase ***,the study on this aspect is absence,because it can hardly exclude the influence of variation in monomer proportion required for tuning the separated phase ***,we report the first study on tuning the phase size through reversible addition-fragmentation chain transfer(RAFT)polymerization without changing the proportion of *** expected,the size of separated phase has been successfully mediated from 15 nm to 9 nm by tuning the molecular weight of the chain transfer *** is found that the mechanical strength and the self-healing efficiency of the resultant polymers increase simultaneously with the decrease of phase *** study on the formation kinetics of hydrogen bonds reveals that the decrease of phase size can facilitate the re-bonding rate of hydrogen bonds,even if the migration of polymer chains is restricted.

关键词： Self-healing polymers Phase separation Reversible addition-fragmentation chain transfer

Hydrogen storage thermodynamics and kinetics of as-cast Ce-Mg-Ni-based alloy

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Journal of Iron and Steel Research International 2024年第3期31卷 752-766页

作者： yan qi Xin Zhang Jun Li Dong-liang Zhao Shi-hai Guo yang-huan Zhang Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China China Rare Earth New Material(Weishan)Co..Ltd. Jining 277600ShandongChina Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina

The reaction kinetics of alloys based on magnesium are known to be greatly improved by the partial substitution of Mg with rare earths and transition metals,particularly *** enhanced superficial hydrogen dissociation rate,the weakened Mg-H bond and the lower activation energy following element replacement are thought to be related to the better *** experimental alloys Ce5Mg_(95-x)Ni_(x)(x=5,10,15)were smelted by the vacuum induction *** phase transformation and structural evolution of experimental alloys before and after reaction with hydrogen were char-acterized by X-ray diffraction,scanning electron microscopy and transmission electron *** cast specimens contain CeMg_(12),Mg and Mg_(2)Ni phases,and the increase in Ni content results in an obvious growth of Mg_(2)Ni *** isothermal and non-isothermal hydrogenation and dehydrogenation kinetics of the experimental specimens were investi-gated using the Sievert apparatus,differential scanning calorimetry and thermal gravimetric *** activation energy may be calculated using the Arrhenius and Kissinger *** experimental alloys have been shown to have good activation properties,with a reversible hydriding and dehydriding capacities of around 5.0 wt.%in the first *** initial dehydrogenation temperature of MgH_(2) decreases from 557.5 to 537.7 K with changing Ni content from 5 to 15 at.%.The dehydrogenation activation energy also reduces from 77.09 to 62.96 kJ/mol,which explains the improved hydrogen storage performance caused by Ni *** can be shown that the impact of Ni on the decomposition enthalpy of MgH_(2) is quite modest,with the absolute enthalpy(ΔHr)only decreasing from 78.48 to 76.15 kJ/mol.

关键词： Mg-based alloy Ni content Hydrogen storage kinetics Thermodynamic property Activation energy

Biotransformation of ethylene glycol by engineered Escherichia coli

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Synthetic and Systems Biotechnology 2024年第3期9卷 531-539页

作者： Wenlong yan Xinhua qi Zhibei Cao Mingdong Yao Mingzhu Ding Yingjin Yuan Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China Frontiers Research Institute for Synthetic Biology Tianjin UniversityTianjin300072China

There has been extensive research on the biological recycling of PET waste to address the issue of plastic waste pollution,with ethylene glycol(EG)being one of the main components recovered from this ***,finding ways to convert PET monomer EG into high-value products is crucial for effective PET waste *** this study,we successfully engineered Escherichia coli to utilize EG and produce glycolic acid(GA),expecting to facilitate the biological recycling of PET *** engineered ***,able to utilize 10 g/L EG to produce 1.38 g/L GA within 96 h,was initially ***,strategies based on overexpression of key enzymes and knock-out of the competing pathways are employed to enhance EG utilization along with GA *** engineered ***,characterized by the highest GA production titer and substrate conversion rate,was *** GA titer increased to 5.1 g/L with a yield of 0.75 g/g EG,which is the highest level in the shake flake *** level analysis and metabolomic analysis were then conducted,revealing that overexpression of key enzymes and knock-out of the competing pathways improved the metabolic flow in the EG *** improved metabolic flow also leads to accelerated synthesis and metabolism of amino acids.

关键词： PET biological recycling Ethylene glycol utilization Glycolic acid production Escherichia coli Synthetic biology Metabolomics analysis

Remaining Useful Life Prediction Method for Multi-Component System Considering Maintenance:Subsea Christmas Tree System as A Case Study

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China Ocean Engineering 2024年第2期38卷 198-209页

作者： WU qi-bing CAI Bao-ping FAN Hong-yan WANG Guan-nan RAO Xi GE Weifeng SHAO Xiao-yan LIU Yong-hong CNOOC Safety Technology Services Co. Ltd.Tianjin 300456China College of Mechanical and Electronic Engineering China University of PetroleumQingdao 266580China CNOOC EnerTech Safety&Environmental Protection BranchTianjin 300456China

Maintenance is an important technical measure to maintain and restore the performance status of equipment and ensure the safety of the production process in industrial production,and is an indispensable part of prediction and health ***,most of the existing remaining useful life(RUL)prediction methods assume that there is no maintenance or only perfect maintenance during the whole life cycle;thus,the predicted RUL value of the system is obviously lower than its actual operating *** complex environment of the system further increases the difficulty of maintenance,and its maintenance nodes and maintenance degree are limited by the construction period and working conditions,which increases the difficulty of RUL *** RUL prediction method for a multi-omponent system based on the Wiener process considering maintenance is *** performance degradation model of components is established by a dynamic Bayesian network as the initial model,which solves the uncertainty of insufficient data *** on the experience of experts,the degree of degradation is divided according to Poisson process simulation random failure,and different maintenance strategies are used to estimate a variety of condition maintenance *** example of a subsea tree system is given to verify the effectiveness of the proposed method.

关键词： remaining useful life Wiener process dynamic Bayesian networks maintenance subsea Christmas tree system

Atomic tailoring-induced deficiency in tungsten oxides for high-performance energy-related devices

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Tungsten 2024年第2期6卷 269-277页

作者： jing-Huang Lin Yao-Tian yan Jun-Lei qi Chen-yang Zha Institute of Applied Physics and Materials Engineering Zhuhai UM Science and Technology Research InstituteUniversity of MacaoTaipaMacao SAR 999078China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China jiangmen Laboratory of Carbon Science and Technology Hong Kong University of Science and Technology(Guangzhou)Jiangmen 529199China Key Laboratory of Flexible Electronics School of Flexible Electronics(Future Technologies)Institute of Advanced MaterialsNanjing Tech UniversityNanjing 211816China

Nowadays,tungsten oxides,as a typical transition metal oxide,are widely and intensively investigated owing to their excellent material properties and device *** oxygen defi ciency in tungsten oxides is typically the key to enhance their performances for a variety of critical technological *** a gradual increase of oxygen defi ciency,various non-stoichiometric tungsten oxides can be formed by re-adjustment of the atomic arrangement,which exhibits superior performances than their traditional stoichiometric *** review mainly focuses on the recent advances in oxygen-defi cient tungsten oxides from the point of atomic structures,including the forming mechanism of non-stoichiometric tungsten oxides and the superiority of these oxygen-defi cient tungsten oxides in energy-related ***,the challenge and perspective of oxygen-defi cient tungsten oxides are also discussed.

关键词： Oxygen defi ciency Tungsten oxide Atomic structures Catalyst Storage