检索结果-南通市图书馆

Elastohydrodynamic Lubrication Interface Stiffness and Damping Considering Asperity Lateral Contact

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第1期37卷 109-123页

作者： Zhiqiang Gao yu zhang xian Wei Yanfang Zhu Lixia Peng Weiping Fu Wen Wang School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048China School of Intelligent Manufacturing Panzhihua UniversityPanzhihua 617000China Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Light Chemical TechnologyYibin 644002China School of Mechanical Engineering Anyang Institute of TechnologyAnyang 455099China

Elastohydrodynamic lubrication(EHL)point contact occurs between two rough surfaces at the mesoscopic level,while the interaction of rough surfaces involves contact between asperities at the microscale *** most cases,the contact between asperities within an interface takes the form of lateral contact rather than peak *** devoid of contact asperities are filled with lubricating ***,conventional models often oversimplify lateral contact forms as interactions between asperities and a smooth,rigid *** simplifications fail to accurately represent the true contact conditions and can lead to inaccuracies in the analysis of EHL’s contact *** address this issue,we have developed a novel EHL interface model comprising two rough *** model allows us to explore the influence of asperity height,contact angle,and contact azimuth angle on EHL interface performance.

关键词： EHL interface Asperity lateral contact Contact stiffness Damping

Microstructure Evolution and Nanomechanical Behavior of Micro-Area in Molten Pool of Selective Laser Melting(CoCrNi)_(82)Al_(9)Ti_(9)High-Entropy Alloy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1019-1033页

作者： Hong-Wei zhang Li-Wei Lan Zhe-yu Yang Chang-Chun Li Wen-xian Wang College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Ministry of Education Key Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyTaiyuan030024China Shanxi-Zhejiang University New Materials and Chemical Research Institute Taiyuan030032China

In this work,the phase evolution mechanism and nanomechanical properties of(CoCrNi))(82)Al_(9)Ti_(9)high-entropy alloy(HEA)prepared by selective laser melting(SLM)in the molten pool were *** HEA contains multiple primary elements and undergoes high-temperature gradient and rapid cooling during *** leads to significant inhomogeneity of nano-scale microstructure characteristics and instability of *** optimizing process parameters,the microstructure evolution at the optimal parameter volume energy density of 440 J/mm^(3)was studied.A phase transition from BCC to FCC occurred in the melt *** the micro-area of the melt pool results in a temperature rise and the combustion-induced loss of Al ***,the Ni element content increases significantly outside the melt *** process enhances the phase stability of FCC and facilitates phase ***,rapid cooling leads to the formation of distinctive ultrafine equiaxial crystals inside the melt pool,accompanied by the generation of intracrystalline needle-like nano-scale *** the melt pool,the accumulation of energy results in the formation of coarse ***,the nano-hardness inside the molten pool is remarkably high at 11.79 GPa,while the outside the molten pool is reduced to 9.58 *** the fracture toughness outside the melt pool also *** with inside the melt pool,the residual stress outside the melt pool changed from compressive to tensile stress and decreased from 603.28 to 322.84 MPa.

关键词： High-entropy alloys Selective laser melting Microstructure evolution Nanoindentation

Predicting dynamic compressive strength of frozen-thawed rocks by characteristic impedance and data-driven methods

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2591-2606页

作者： Shengtao Zhou Zong-xian zhang Xuedong Luo Yifan Huang Zhi yu Xiaowei Yang Faculty of Engineering China University of GeosciencesWuhan430074China Oulu Mining School University of OuluOulu90570Finland Zijin School of Geology and Mining Fuzhou UniversityFuzhou350116China Department of Earth Science&Engineering Imperial College LondonLondonSW72AZUK

In cold regions,the dynamic compressive strength(DCS)of rock damaged by freeze-thaw weathering significantly influences the stability of rock ***,testing the dynamic strength under freeze-thaw weathering conditions is often both time-consuming and ***,this study considers the effect of characteristic impedance on DCS and aims to quickly determine the DCS of frozen-thawed rocks through the application of machine-learning ***,a database of DCS for frozen-thawed rocks,comprising 216 rock specimens,was *** external load parameters(freeze-thaw cycle number,confining pressure,and impact pressure)and two rock parameters(characteristic impedance and porosity)were selected as input variables,with DCS as the predicted *** research optimized the kernel scale,penalty factor,and insensitive loss coefficient of the support vector regression(SVR)model using five swarm intelligent optimization algorithms,leading to the development of five hybrid *** addition,a statistical DCS prediction equation using multiple linear regression techniques was *** performance of the prediction models was comprehensively evaluated using two error indexes and two trend indexes.A sensitivity analysis based on the cosine amplitude method has also been *** results demonstrate that the proposed hybrid SVR-based models consistently provided accurate DCS *** these models,the SVR model optimized with the chameleon swarm algorithm exhibited the best performance,with metrics indicating its effectiveness,including root mean square error(RMSE)?3.9675,mean absolute error(MAE)?2.9673,coefficient of determination(R2)?0.98631,and variance accounted for(VAF)?*** suggests that the chameleon swarm algorithm yielded the most optimal results for enhancing SVR ***,impact pressure and characteristic impedance emerged as the two most influential parameters in DCS *** research is ant

关键词： Freeze-thaw cycle Characteristic impedance Dynamic compressive strength Machine learning Support vector regression

Stabilization/solidification mechanisms of tin tailings and fuming slag-based geopolymers for different heavy metals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第5期18卷 43-55页

作者： xian Zhou Zhengfu zhang Hui Yang School of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China Kunming Metallurgical Research Institute Co. Ltd.Kunming650031China

Tin mine tailings(TMT)and fuming slag(FS)contain many heavy metals(As,Cr,Cu,Zn and Mn)that cause severe pollution to the ***,geopolymers were prepared using TMT,FS and flue gas desulfurization gypsum(FGDG)to immobilize heavy metals,and their compressive strength and heavy metal leaching toxicity were *** was first determined that T4F5(TMT:FS=4:5)sample exhibited the highest compressive strength(7.83 MPa).T4F5 achieved 95%immobilization efficiency for As and Cr,and nearly 100%for Cu,Zn and Mn,showing good immobilization performance.A series of characterization analyses showed that heavy metal cations can balance the charge in the geopolymer and replace Al in the geopolymer structure to form covalent *** addition,about 2%–20%of heavy metal Fe was immobilized in hydration products,heavy metal hydroxides and non-bridging Si–O and Al–O coordination with silica-aluminate ***_(3)^(3−) was oxidized into AsO_(4)^(3−),which may form Ca–As or Fe–As ***_(2)O_(7)^(2−)was converted to CrO_(4)^(2−)under alkaline environment and then combined with OH−to form Cr(OH)3 ***^(2+)may react directly with dissolved silicate to form Mn_(2)SiO_(4) and also form Mn(OH)_(2) *** unstable Mn(OH)_(2) can be further oxidized to MnO_(2).The heavy metal cations were immobilized in the silicoaluminate lattice,while the anions tended to form insoluble *** results may benefit the industry and government for better handling of TMT,FS and solid wastes containing the abovementioned five heavy metals.

关键词： Heavy metals Cementitious materials Tin tailings Stabilization/solidification Redox

PACS gene family-related neurological diseases: limited genotypes and diverse phenotypes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第1期20卷 82-91页

作者： Han zhang Kai Gao Shuang Wang yue-Hua zhang Zhi-xian Yang Ye Wu yu-Wu Jiang Department of Pediatrics Peking University First Hospital.No.1 Xi'an Men StreetWest DistrictBeijing 100034China Bejing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases BeijingChina Children Epilepsy Center Peking University First HospitalBeijingChina Key Laboratory for Neuroscience Ministry of Education/National Health and Family Planning CommissionPeking UniversityBeijingChina Center of Epilepsy Beijing Institute for Brain DisordersBeijingChina

Background The PACS gene family has been demonstrated to be related to intracellular vesicular *** phenotypic manifestations caused by the pathogenic variants of PACS include epilepsy,intellectual disability/developmental delay,and malformations,such as facial *** We identified seven new cases with pathogenic or likely pathogenic PACS variants using next-generation *** information obtained from these patients was analyzed along with that obtained from previously reported *** With the inclusion of the newly diagnosed cases in this study,103 cases with PACS gene family-related neurological diseases were reported,of which 43 were PACS2-related cases and the remaining were PACSI-related *** patients had seizures,which have been reported to be effectively controlled by several types of anti-seizure medications(ASMs).The most efficacious and frequently prescribed ASMs included sodium valproate(43.3%,13/30),oxcarbazepine/carbamazepine(26.7%,8/30),and levetiracetam(20%,6/30).Almost all patients had intellectual disability/developmental *** most common pathogenic missense variants were PACSI ***203Trp and PACS2 *** addition,we report a patient carrying a likely pathogenic copy number variation(CNV)(de novo heterozygous deletion of chr14:105821380-106107443,286 kilobase,destroyed part of the furin-binding region domain and the protein structure after it)with more severe and refractory late-onset *** The clinical phenotypes of the different PACS heterozygous missense variants were *** pathogenic variant sites of PACSI and PACS2 were quite limited but located in different regions.A CNV destroying part of the PACS2 gene might also be *** findings may provide an important clue for further functional studies on the pathogenic mechanism of neurological disorders related to the PACS gene family.

关键词： Developmental delay Epilepsy Intellectual disability PACSI PACS2

Three-dimensional porous bimetallic metal–organic framework/gelatin aerogels: A readily recyclable peroxymonosulfate activator for efficient and continuous organic dye removal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第7期71卷 193-202页

作者： Wenlong xiang xian zhang Rou Xiao Yanhui zhang College of Chemistry Chemical Engineering and EnvironmentFujian Province Key Laboratory of Morden Analytical Science and Separation TechnologyMinnan Normal UniversityZhangzhou 363000China Fujian Provincial University Key Laboratory of Pollution Monitoring and Control Minnan Normal UniversityZhangzhou 363000China

As promising catalysts for the degradation of organic pollutants,metal–organic frameworks(MOFs)often face limitations due to the particle agglomeration and challenging recovery in liquid-catalysis application,stemming from their powdery *** macroscopic structures from pulverous MOF is thus of great importance for broadening their practical *** this study,three-dimensional porous MOF aerogel catalysts were successfully fabricated for degrading organic dyes by activating peroxymonosulfate(PMS).MOF/gelatin aerogel(MOF/GA)catalysts were prepared by directly integrating bimetallic FeCo-BDC with gelatin solutions,followed by freeze-drying and low-temperature *** FeCo-BDC-0.15/GA/PMS system exhibited remarkable performance in degrading various organic dyes,eliminating 99.2%of rhodamine B within a mere 5 *** to the GA/PMS system,there was over a 300-fold increase in the reaction rate ***,high removal efficiency was maintained across varying conditions,including different solution pH,co-existing inorganic anions,and natural water *** trapping experiments and electron paramagnetic resonance analysis revealed that the degradation involved radical(SO_(4)^(-)·)and non-radical routes(^(1)O_(2)),of which ^(1)O_(2) was ***,even after a continuous 400-min reaction in a fixed-bed reactor at a liquid hourly space velocity of 27 h^(-1),the FeCo-BDC/GA composite sustained a degradation efficiency exceeding 98.7%.This work presents highly active MOF-gelatin aerogels for dye degradation and expands the potential for their large-scale,continuous treatment application in organic dye wastewater management.

关键词： Catalyst Environment Wastewater Metal–organic framework Gelatin aerogel Peroxymonosulfate

Chemical modification of barite for improving the performance of weighting materials for water-based drilling fluids

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 551-566页

作者： Li-Li Yang Ze-yu Liu Shi-bo Wang xian-Bo He Guan-Cheng Jiang Jie zhang MOE Key Laboratory of Petroleum Engineering State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Changping DistrictBeijing102249China MOE Key CNPC Drilling Research Institute Changping DistrictBeijing102206China

With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore *** this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite *** suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of *** viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same *** multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of *** sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was ***,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection *** work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.

关键词： Drilling fluids Weighting materials Filtration control Reservoir protection Stability property

Cross section determination of^(27)Al(n,2n)^(26)Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第6期35卷 78-89页

作者： xian-Lin Yang Chang-Lin Lan yu-Ting Wei Yi zhang Gong Jiang Bo Xie yu Liu Hong-Tao Shen Xiao-Jun Sun School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology Guangxi Normal UniversityGuilin 541004China

Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great *** address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion *** the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He ***^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of *** neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb *** measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature *** newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental *** obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.

关键词： 14-MeV neutron ^(27)Al(n,2n)^(26)Al Cross section AMS

Hybrid vibration isolation optimization of a flexible manipulator based on neural network agent model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第5期37卷 482-505页

作者： Yongxin zhang Liang LI Dingguo zhang Wei-Hsin LIAO xian GUO School of Science Nanjing University of Science and TechnologyNanjing 210094China Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

Segmented Active Constrained Layer Damping(SACLD)is an intelligent vibration-damping structure,which could be applied to the sectors of aviation,aerospace,and transportation engineering to reduce the vibration of flexible ***,machine learning technology is widely used in the engineering field because of its efficient multi-objective *** dynamic simulation of a rotational segmental flexible manipulator system is presented,in which enhanced active constrained layer damping is carried out,and the neural network model of Genetic Algorithm-Back Propagation(GA-BP)algorithm is *** suppression and structural optimization of the SACLD manipulator model are studied based on vibration mode and damping *** modal responses of the SACLD manipulator model at rest and rotation are *** addition,the four model indices are optimized using the GA-BP neural network:axial incision size,axial incision position,circumferential incision size,and circumferential incision ***,the best model for vibration suppression is obtained.

关键词： Machine learning Vibration suppression Flexible manipulator Segmented active constrained layer damping Structural optimization