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Experimental Study on Vortex-Induced Vibration of Rough Risers Coupling with Interference Effect in Tandem Arrangement

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China Ocean Engineering 2024年第3期38卷 394-407页

作者： HU Ze-bo LIU Zhen LI Peng guo Hai-yan REN Xiao-hui HOU hao hao Lian-hong College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Qingdao Key Laboratory of Marine Civil Engineering Materials and Structures Qingdao 266590China College of Engineering Ocean University of ChinaQingdao 266100China

In order to study the response law of vortex-induced vibration(VIV)of marine risers under the combined action of roughness and interference effects,and to reveal the coupling mechanism of roughness and interference effects on the riser,a VIV experiment of rough risers in tandem arrangement was conducted in a wave−current combined *** experiment characterized the risers’roughness by arranging different specifications of attachments on the surface of the *** rough risers with different roughness and smooth risers were arranged in tandem arrangement,with the rough risers arranged *** experimental results indicate that the suppression of the attachments on the downstream risers’vibration are more significant both in the CF and IL directions as the reduced velocity *** the downstream riser,the amplitude response of rough riser is more significantly weakened compared with the smooth one at high reduced *** the upstream risers,changes in the roughness and spacing ratio have an impact on their‘lock-in’*** the roughness of downstream risers is relatively large(0.1300)and the spacing between risers is small(S/D=4.0),the reduced velocity range of‘lock-in’region in the CF direction of upstream risers is obviously expanded,and the displacement in the‘lock-in’region is severer.

关键词： marine riser vortex-induced vibration tandem arrangement roughness interference effect

Rapid discovery of two unprecedented meroterpenoids from Daphne altaica *** molecular networking integrated with MolNetEnhancer and Network Annotation Propagation

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Chinese Chemical Letters 2024年第8期35卷 294-298页

作者： Wei-Yu Zhou Zi-han Xi Ning-Ning Du Li Ye Ming-hao Jiang Jin-Le hao Bin Lin guo-Dong Yao Xiao-Xiao Huang Shao-Jiang Song Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research&Development Liaoning ProvinceEngineering Research Center of Natural Medicine Active Molecule Research&DevelopmentLiaoning ProvinceKey Laboratory of Natural Bioactive Compounds Discovery&ModificationShenyangSchool of Traditional Chinese Materia Medic1Shenyang Pharmaceutical UniversityShenyang 110016China Key Laboratory of Structure-Based Drug Design and Discovery of Ministry of Education Shenyang Pharmaceutical UniversityShenyang 110016China Wuya College of Innovation Shenyang Pharmaceutical UniversityShenyang 110016China

Under the guidance of the approach which integrates molecular networking,MolNetEnhancer and Net-work Annotation Propagation(NAP),daphnaltaicanoids A and B(1 and 2)with unprecedented 9-oxa-tetracyclo[6.***.1.0^(2,6).0^(8,13)]pentadecane and tetracyclo[5.***.0.1^(2,5).2^(4,11)]tridecane central frameworks were iso-lated from Daphne altaica Pall.,representing two types of unparalleled meroterpenoid *** struc-tures were elucidated by extensive spectroscopic analysis,nuclear magnetic resonance(NMR)calcula-tions,DP4+analysis and electronic circular dichroism(ECD)*** plausible biosynthetic path-ways for 1 and 2 were ***,2 exerted potent neuroprotective activities which were su-perior to trolox at 12.5 and 25μmol/***,1 and 2 exhibited more noticeable acetylcholinesterase inhibitory activities than *** docking simulations were performed to explore the inter-molecular interaction of compounds 1 and 2 with *** bioactivity evaluation results highlight the prospects of 1 and 2 as a novel category of neurological agents.

关键词： Daphne altaica Pall. Molecular networking MolNetEnhancer NAP Unprecedented meroterpenoid frameworks Neuroprotective activities Acetylcholinesterase inhibitors

Nonlinear empirical failure criterion for rocks under triaxial compression

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International Journal of Mining Science and Technology 2024年第3期34卷 351-369页

作者： Hongtao Liu Zhou han Zijun han Zihan Chen Qinyu Liu Hongkai Zhang Rongguang Zhang Linfeng guo School of Energy&Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China China National Coal Association Beijing 100010China

Based on existing triaxial compression experimental data,a new empirical failure criterion with wide applicability was proposed considering hydrostatic pressure,second stress invariance,and maximum shear *** fitting evaluation indicators were used to verify the consistency of the new failure criterion,and the differences with the other 6 failure criteria were *** characteristics of the new failure criteria in the principal stress space were finally *** results indicate that(1)the new failure criterion exhibits strong predictive ability for triaxial experiments and has good applicability for both intact and jointed rocks;(2)the influence of hydrostatic pressure on the failure surface exhibits a non-linear trend,and different hydrostatic pressure also exhibits different distribution patterns on the deviatoric stress plane,with a distribution characteristic pattern of hexagonal snowflake-regular *** maximum shear stress has a torsional effect on the new criterion,in the three-dimensional failure *** parameters a and b of the rock have an impact on the failure surface morphology of the new criterion function on the offset surface.

关键词： surface. criterion hydrostatic

Escape probability for isotropic emitters near Kerr black hole with astrometric

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Communications in Theoretical Physics 2024年第5期76卷 128-133页

作者： Yu-Xuan han Qing-Hua Zhu Qing-guo Huang CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China Department of Physics Chongqing UniversityChongqing 401331China School of Fundamental Physics and Mathematical Sciences hangzhou Institute for Advanced Study UCASHangzhou 310024China

The paper investigates the escape probability for isotropic emitters near a Kerr black *** propose a new approach to obtain the escape probability in a general manner,going beyond previous case-by-case *** approach is based on studies of the black hole shadow with astrometric observable and can be applied to emitters with an arbitrary 4-velocities and locations,even to the emitters outside of the equatorial *** also consider representative examples illustrating how escape probabilities vary with distance,velocity,and inclination ***,this new approach provides an effective method for studying escape probabilities near Kerr black holes.

关键词： Kerr black hole photon escape probability isotropic emitters

4-Nitrocatechol as a novel matrix for low-molecular-weight compounds in situ detection and imaging in biological tissues by MALDI-MSI

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Chinese Chemical Letters 2024年第6期35卷 486-490页

作者： Hualei Xu Manman han Haiqiang Liu Liang Qin Lulu Chen hao Hu Ran Wu Chenyu Yang Hua guo Jinrong Li Jinxiang Fu Qichen hao Yijun Zhou Jinchao Feng Xiaodong Wang Key Laboratory of Mass Spectrometry Imaging and Metabolomics(Minzu University of China) State Ethnic Affairs CommissionBeijing 100081China College of Life and Environmental Sciences Centre for Imaging&Systems BiologyMinzu University of ChinaBeijing 100081China

Low-molecular-weight(LMW)compounds are ubiquitous in living organisms and play essential roles in biological *** direct analysis of LMW compounds in biological tissues by matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI)could provide a more comprehensive understanding of their essential ***,we evaluated 4-nitrocatechol(4-NC)as a novel positive-ion matrix for enhancing in situ detection and imaging of LMW compounds from the rat liver,brain,and germinating Chinese-yew seed by *** results showed that the 4-NC possessed remarkable features,including strong ultraviolet absorption,uniform matrix crystal,excellent chemical stability,and fewer matrix-related background *** use of 4-NC led to the successful detection of 232,218,and193 LMW compounds from the three abovementioned tissue sections,***,the use of 4-NC improved the imaging quality of LMW compounds in tissue sections through MALDI-MSI and has the potential as a matrix for MALDI tissue imaging of LMW compounds.

关键词： MALDI-MSI 4-Nitrocatechol LMW compounds In situ detection Tissue imaging

Promoted catalytic performance of Ag-Mn bimetal catalysts synthesized through reduction route

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Journal of Environmental Sciences 2024年第3期137卷 358-369页

作者： Wenkai Hu Tao guo Kaiyao Ma Xu Li Wangting Luo Mingzhi Wu hao guo Yaxin Zhang Wenfeng Shangguan School of Chemical Engineering and Technology Xinjiang UniversityUrumchi 830017China Research Center for Combustion and Environmental Technology Shanghai Jiao Tong UniversityShanghai 200240China

VOCs can exert great harm to both human and environment,and catalytic oxidation is believed to be an effective technique to eliminate these *** this paper,Ag-Mn bimetal catalysts with 10 wt.%of silver were synthesized using doping,impregnation,and reduction methods respectively,and then they were applied to the catalytic oxidation of *** series of characterizations it showed that the loading of silver using reduction method significantly resulted in improved physico-chemical properties of manganese oxides,such as larger surface area and pore volume,higher proportion of surface Mn~(3+)and Mn~(4+),stronger reducibility and more active of surface oxygen species,which were all beneficial to its catalytic *** a result,the Ag-Mn catalysts synthesized by reduction method showed a lower T_(90)value(equals to the temperature at which 90%of initial benzene was removed)of 203℃.Besides,both the used and fresh Ag-Mn catalysts synthesized by reduction method showed preferable stability in this research.

关键词： Ag-Mn Benzene oxidation Catalytic performance Reduction route

Roles of Cu doping in YbZn_(2)Sb_(2) for thermoelectric performance enhancement

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Rare Metals 2024年第6期43卷 2869-2875页

作者： Xiong Zhang Hai-Hui Li Xiao-Liang Cao Bin Zhang Hong Wu Yu Zhang Guang han guo-Yu Wang hao-Shuang Gu Xiao-Yuan Zhou College of Physics and Electronic Science Hubei Normal UniversityHuangshi 435002China Analytical and Testing Center Chongqing UniversityChongqing401331China School of Science Chongqing University of Posts and Telecommunications.Chongqing 400065 China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials-Hubei Key Laboratory of Ferro&Piezoelectric Materials and Devices Faculty of Physical and Electronic SciencesHubei UniversityWuhan 430062China College of Physics Chongqing UniversityChongqing 401331China

Recent research shows that increasing the carrier density after orbital alignment in AZn_(2)Sb_(2) (A=Ca,Yb,Eu,Sr,Mg)Zintl compounds yields remarkable results with regard to enhanced thermoelectric ***,research on carrier density increase via doping in these compounds is *** this study,we introduced Cu into the Zn sites in YbZn_(2)Sb_(2) and examined the thermoelectric properties.

关键词： properties doping performance

Characteristics and stability of oxide+carbonitride in H13 steel at 1250℃

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Journal of Iron and Steel Research International 2024年第1期31卷 134-142页

作者： Xiao-lin Sun han-jie guo Jing guo Fei Wang Dong Xu Gao-yang Song Shuai Wang School of Materials Science and Engineering Hebei University of EngineeringHandan056038HebeiChina School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China High Temperature Materials Research Institute Central Iron and Steel Research Institute Co.Ltd.Beijing100081China Technology Innovation Center for High Quality Cold Heading Steel of Hebei Province Hebei University of EngineeringHandan056038HebeiChina

The morphology,size,quantity,and composition of complex oxide+carbonitride in H13 steel held at 1250℃for 5,10,and 15 h were *** results show that the ratio and number of complex carbonitrides with cores in H13 steel are gradually increased when holding at 1250℃compared with those in the original H13 steel,and the core size *** are one or more oxide cores in(Ti_(x),V_(1-x))(Cy,N_(1-y)),including xCaO·zAl_(2)O_(3),xCaO·yMgO·zAl_(2)O_(3),and CaO after holding at 1250℃,in addition to MgO·Al_(2)O_(3)and Al_(2)O_(3)in the original *** equilibrium temperature for(Ti_(x),V_(1-x))(Cy,N_(1-y))precipitation at the solidification front and decomposition in the solid state was theoretically analyzed,which was affected by the x value and the product of Ti and N contents in H13 ***,the composition of(Ti_(x),V_(1-x))(Cy,N_(1-y))is influenced by the oxide *** is convinced that(Ti_(x),V_(1-x))(Cy,N_(1-y))with oxide cores has a higher stability,especially for oxides with a high Al_(2)O_(3)*** treatment at high temperature facilitates a more reasonable analysis of oxide+carbonitride,and the generation mechanism of oxide+carbonitride was discussed.

关键词： Complex carbonitride Decomposition Oxide core Characteristic Stability

Reduction behavior of iron ore powder by high-volatile coal in thermogravimetric-gas chromatographic and kinetic analysis

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Journal of Iron and Steel Research International 2024年第1期31卷 92-107页

作者： Rui-meng Shi Qi-yuan Mi Bin Li Xiao Shi Chong Zou Jing guo han-jie guo School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina China International Engineering Consulting Corporation Beijing100048China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The reduction behavior of iron ore powder by high-volatile coal was investigated,and its kinetic mechanism was *** effect of volatiles in coal on the reduction reaction of iron ore was compared by utilizing a Xinjiang lignite with a high volatile content and its pyrolysis carbon produced by high-temperature pyrolysis to remove volatiles,serving as a *** mass loss and gas composition of the samples during the reduction process were detected using thermo-gravimetric analysis and gas chromatography,and the morphological changes of iron ore powder were observed through scanning electron *** kinetic parameters of the iron oxide reduction reaction were calculated by the Flynn-Ozawa-Wall method,and the kinetic mechanism of volatile participation in the iron oxide reduction reaction was determined through the Coats-Redfern *** results indicate that the coupling effect between the high-volatile coal pyrolysis and reduction reactions occurs during the second stage of the entire coupling process,which corresponds to the late stage of coal pyrolysis with a substantial release of H_(2)and *** volatiles in coal actively participated in the reduction reaction,reducing the initiation temperature of the reaction by around 200℃.The reduction of iron oxides by high-volatile coal was jointly promoted by the"hydrogen cycle"and"carbon cycle",resulting in a higher reduction extent and metallization rate at the end of the *** high-volatile coal was used as the reductant,the average activation energy for the entire process was 76.5 kJ/mol,a significant decrease compared to the employment of pyrolysis carbon without volatiles as the reductant(1167 kJ/mol).

关键词： Direct reduction High-volatile coal Volatile Kinetics Reduction mechanism