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Journal of Iron and Steel Research International 2024年第8期31卷 2002-2013页

作者： Shuai Wang Jie li li-yang Zeng Xun-wei Zuo Nai-lu Chen yong-hua Rong Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The metastable retained austenite(RA)plays a significant role in the excellent mechanical performance of quenching and partitioning(Q&P)steels,while the volume fraction of RA(V_(RA))is challengeable to directly predict due to the complicated relationships between the chemical composition and process(like quenching temperature(Qr)).A Gaussian process regression model in machine learning was developed to predict V_(RA),and the model accuracy was further improved by introducing a metallurgical parameter of martensite fraction(fo)to accurately predict V_(RA) in Q&P *** developed machine learning model combined with Bayesian global optimization can serve as another selection strategy for the quenching temperature,and this strategy is very effcient as it found the"optimum"Qr with the maximum V_(RA) using only seven consecutive *** benchmark experiment also reveals that the developed machine learning model predicts V_(RA) more accurately than the popular constrained carbon equilibrium thermodynamic model,even better than a thermo-kinetic quenching-partitioning-tempering-local equilibrium model.

关键词： Q&P steel Retained austenite fraction Machine learning Quenching temperature Gaussian process regression model

Oil-soluble polymer brushes-functionalized nanoMOFs for highly efficient friction and wear reduction

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Friction 2024年第7期12卷 1499-1511页

作者： Jianxi liU yong QIAN Dongsheng li Wei WU Mengchen ZHANG Jie YAN Bin li Feng ZHOU State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China Shaanxi Engineering Research Center of Special Sealing Technology Xi'an Aerospace Propulsion InstituteXi'an 710100China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Nanomaterials as lubricating oil additives have attracted significant attention because of their designable composition and structure,suitable mechanical property,and tunable surface ***,the poor compatibility between nanomaterials and base oil limits their further *** this work,we demonstrated oil-soluble poly(lauryl methacrylate)(PLMA)brushes-grafted metal-organic frameworks nanoparticles(nanoMOFs)as lubricating oil additives that can achieve efficient friction reduction and anti-wear *** were synthesized by free-radical polymerization,which was coordinatively grafted onto the surface of the UiO-67 ***,PLMA brushes were grown on the macroinitiator-modified UiO-67 by surface-initiated atom transfer radical polymerization,which greatly improved the lipophilic property of the UiO-67 nanoparticles and significantly enhanced the colloidal stability and long-term dispersity in both non-polar solvent and base *** adding UiO-67@PLMA nanoparticles into the 500 SN base oil,coefficient of friction and wear volume reductions of 45.3%and 75.5%were achieved due to their excellent mechanical properties and oil ***,the load-carrying capacity of 500 SN was greatly increased from 100 to 500 N by the UiO-67@PLMA additives,and their excellent tribological performance was demonstrated even at a high friction frequency of 65 Hz and high temperature of 120℃.Our work highlights oil-soluble polymer brushes-functionalized nanoMOFs for highly efficient lubricating additives.

关键词： MOFs polymer brushes surface modification tribological properties friction reduction anti-wear

Effect of Molecular Weight on Thermoelectric Performance of P3HT Analogues with 2-Propoxyethyl Side Chains

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 268-281页

作者：董得福 WANG Wei ZHAN chun li Chenglong ZHOU Qisheng 肖生强 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for *** close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi *** main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution.

关键词： conjugated polymer molecular weight microstructure thermoelectric performance

Flow resistance in the channel-bar landscape of large alluvial rivers

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Frontiers of Earth Science 2024年第2期18卷 412-421页

作者： yong HU Congcong liU Jinyun DENG Wei ZHANG Yitian li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China CCCC Second Harbor Engineering Company Ltd Wuhan 430040China Key Laboratory of Large-span Bridge Construction Technology Wuhan 430040China Research and Development Center of Transport Industry of Intelligent Manufacturing Technologies of Transport Infrastructure Wuhan 430040China CCCC Highway Bridge National Engineering Research Centre Co.Ltd Wuhan 430040China

Accurate approaches for estimating flow resistance in large alluvial rivers are fundamental for simulating discharge,sediment transport,and flood ***,methods for estimating riverbed resistance and additional resistance in the channel-bar landscapes remain poorly *** this study,we used in situ river bathymetry,sediment,and hydraulic data from the Shashi Reach in the Yangtze River to develop a semi-empirical approach for calculating flow *** method quantitatively separates flow resistance into riverbed resistance and additional resistance and shows high accuracy in terms of deviation ratio(~20%),root-mean-square error(~0.008),and geometric standard deviation(~3).Additional resistance plays a dominant role under low-flow conditions but a secondary role under high flows,primarily due to the reduction in momentum exchange in channel-bar regions as discharge *** resistance first decreases and then increases,which might be attributed to bedform changes in the lower and transitional flow regimes as flow velocity ***,our findings further the understanding of dynamic changes in flow resistance in the channel-bar landscapes of large river systems and have important implications for riverine ecology and flood management.

关键词： flow resistance channel-bar landscape interaction region large river bedform

Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2607-2628页

作者： Hao Chen yong Kang Wanchun Jin Changhai li Can Cai School of Mechanical Engineering Southwest Petroleum UniversityChengdu610500China Laboratory of High-pressure Jet Theory and Application Technology Southwest Petroleum UniversityChengdu610500China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072China Sinopec International Petroleum Exploration and Production Corporation Beijing 100029China

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse *** this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale *** coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing *** on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are *** results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main *** bedding and in situ stress play a dominant role in the fracture *** the in situ stress ratio(δ_(x)/δ_(y))is 1,the presence of bedding can reduce the initiation pressure and failure ***,it will cause the fracture to propagate along the bedding direction,reducing the fracture *** rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced *** shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation ***,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing *** the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly *** results are instructive for the design and application of SC

关键词： Compound fracturing Fracture propagation Finite element method Damage evolution

Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the Early Cambrian,SW China:Constraints from in situ LA-ICP-MS Analysis of Pyrite

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 416-429页

作者： YANG Zhen FU yong li Chao CAI Xi GUO Chuan College of Eco-Environmental Engineering Guizhou Minzu UniversityGuiyang 550025China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and the Environment Ministry of EducationGuizhou UniversityGuiyang 500025China National Research Center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China

A polymetallic layer is usually developed at the bottom of the early Cambrian black shale in Guizhou *** mineral that makes up the polymetallic layer is related to the sedimentary *** analyze the differentiation mechanism between polymetallic deposits(Ni-Mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of *** results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan *** isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive Yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional *** sulfur in the Ni-Mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from ***,the Ni-Mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

关键词： sedimentary environment black shale polymetallic layer pyrite early Cambrian

Present situation of minimally invasive surgical treatment for early gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1154-1165页

作者： chun-Yan li Yi-Feng Wang li-Kang Luo Xiao-Jun Yang The First Clinical Medical School Lanzhou UniversityLanzhou 730000Gansu ProvinceChina The First Clinical Medicine College Gansu University of Chinese MedicineLanzhou 730000Gansu ProvinceChina General Surgery Clinical Centre Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina The Second Department of General Surgery Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina Lanzhou University People's Clinical Hospital Lanzhou 730000Gansu ProvinceChina Gansu Research Center of Prevention and Control Project for Digestive Oncology Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina Gansu Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina

Minimally invasive surgery is a kind of surgical operation,which is performed by using professional surgical instruments and equipment to inactivate,resect,repair or reconstruct the pathological changes,deformities and wounds in human body through micro-trauma or micro-approach,in order to achieve the goal of treatment,its surgical effect is equivalent to the traditional open surgery,while avoiding the morbidity of conventional surgical *** addition,it also has the advantages of less trauma,less blood loss during operation,less psychological burden and quick recovery on patients,and these minimally invasive techniques provide unique value for the examination and treatment of gastric cancer *** minimally invasive surgical techniques have developed rapidly and offer numerous options for the treatment of early gastric cancer(EGC):endoscopic mucosal resection(EMR),underwater EMR(UEMR),endoscopic submucosal dissection(ESD),endoscopic full-thickness resection(EFTR),endoscopic submu-cosal excavation(ESE),submucosal tunnel endoscopic resection,laparoscopic and endoscopic cooperative surgery(LECS);Among them,EMR,EFTR and LECS technologies have a wide range of applications and different modific-ations have been derived from their respective surgical operations,such as band-assisted EMR(BA-EMR),conven-tional EMR(CEMR),over-the-scope clip-assisted EFTR,no-touch EFTR,the inverted LECS,closed LECS,and so *** new and improved minimally invasive surgeries are more precise,specific and effective in treating different types of EGC.

关键词： Minimally invasive surgery Early gastric cancer Endoscopic mucosal resection Endoscopic full-thickness resection Laparoscopic and endoscopic cooperative surgery

Diffusion of nanochannel-confined knot along a tensioned polymer

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Communications in Theoretical Physics 2024年第4期76卷 158-166页

作者： Guobing Cai yong li Yuyu Feng Zhouhui Deng Yanhui liu College of Physics Guizhou UniversityGuiyang 550025China Kechuang Industrial Development Company limited Guian New AreaGuiyang 550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China

The knots frequently occur in biopolymer and their diffusion plays an active role in the gene *** this work,Langevin dynamics simulations were carried out to detect the diffusion behaviours of a knot along a tensioned polymer in different spatial *** polymer accommodating a knot was tethered to two macrospheres to block the unravelling of the *** a result,the curves for the diffusion coefficients of the knot with different bending stiffness as a function of the tension in different spatial constraints were *** the space without constraints or with weak constraints,the corresponding curves for the knot with relatively large bending stiffness exhibited two turnover *** the contrary,for the knot with relatively small bending stiffness,the diffusion coefficients were monotonically reduced with increasing ***,in a space with strong constraints,all the curves showed one turnover behaviour regardless of the bending *** turnover behaviours divided the curves into different regimes,and the dominant diffusion mechanisms in the regimes,namely,knot-region breathing,self-reptation,and internal friction,were clearly *** effective friction coefficientsξof the knots with 3_(1),4_(1),5_(1) and 5_(2) types as a function of the knot size N at a fixed tension were well fitted by the relationξ∝*** effective friction coefficients of the knots at relatively large tension f>3 sharply increased with the knot complexity,which is not dependent on the spatial *** contrast,the values of these coefficients at relatively small tension f≤3 were remarkably dependent on the spatial *** work not only provides valuable simulation results to assist the understanding of the diffusion of DNA knot,but also highlights the single-molecule design for the manipulation of DNA knots in future.

关键词： knot langevin dynamics simulations diffusion coefficient self-reptation knot-region breathing internal friction

Taxonomy of Two New Peritrich Ciliates(Protozoa:Ciliophora)from Inland Saltwaters of China

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Journal of Ocean University of China 2024年第3期23卷 811-821页

作者： YU Ying ZHANG yong liANG Ziyao li Jiqiu liN Xiaofeng Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems Fujian Provincial Key Laboratory of Coastal Ecology and Environmental StudiesCollege of the Environment and EcologyXiamen UniversityXiamen 361102China School of life Science South China Normal UniversityGuangzhou 510631China State Key Laboratory of Marine Environmental Science Xiamen UniversityXiamen 361102China

The inland saltwater lakes harbor exceptional ***,two new species of solitary sessile peritrich ciliates were isolated from Qinghai Lake,the largest inland saltwater lake in *** morphology,ciliature,silverline system,and molecular phylogeny were investigated based on live observation,silver staining,and analysis of the small subunit ribosomal DNA(SSU rDNA).Vorticella paraglobosa *** characterized mainly by its obconical or elongate bell-shaped zooid,C-shaped macronucleus,single ventrally located contractile vacuole,two-rowed infundibular polykinety 3,and 28-38 silverlines between peristome and aboral tro-chal band and 10-15 between aboral trochal band and *** cotyliformis *** from its congeners mainly by its double-layered peristomial lip,cup-shaped zooid,J-shaped macronucleus,single ventrally positioned contractile vacuole,three-rowed infundibular polykinety 3,and 70-85 silverlines between peristome and aboral trochal band and 21-25 between aboral trochal band and *** SSU rDNA sequences of the two new species were obtained,and the subsequent molecular phylogenetic analysis supported their taxonomic classification.

关键词： molecular phylogeny morphology new species Qinghai Lake taxonomy

Effect of post rolling stress on phase transformation behavior of microalloyed dual phase steel

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Journal of Iron and Steel Research International 2024年第3期31卷 688-699页

作者： Wen-quan Sun Sheng-yi yong Tie-heng Yuan Ting-song Yang An-rui He Chao liu Rui-chun Guo National Engineering Research Center for Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing 100083China

The slow phase transformation of microalloyed dual phase steel makes the nonuniform stress and temperature fields during the post rolling cooling process have a significant impact on the phase transformation *** the relatively slow phase transformation of DP780 steel within the microalloyed dual phase steel series,the influence of stress on the phase transformation behavior of DP780 steel was *** quantify the nonuniform thermal and stress conditions in the steel coil,a thermo-mechanical coupled finite element model of the hot-rolled strip cooling process was *** on the simulation data,DP780 steel was chosen as the research material,and Gleeble 3500 thermal simulation equipment was used for experimental *** thermal expansion curves were analyzed through regression to establish the dynamic model of DP780 steel phase transformation under ***,metallographic analysis was conducted to determine phase transformation type and grain size of DP780 *** results confirmed that the stress promotes the occurrence of semi-diffusion-type bainite ***,an appropriate level of stress facilitates the growth of bainitic grains,while the increased stress inhibits the growth of ferritic grains.

关键词： Microalloyed dual phase steel Stress Bainitic transformation Grain Finite element method