检索结果-南通市图书馆

High-Temperature Oxidation Behavior of Vanadium,Titanium-Bearing Magnetite Pellet

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第8期18卷 14-19页

作者： HAN gui-hong JIANG tao zhang Yuan-bo HUANG Yan-fang LI Guang-hui School of Minerals Processing and Bioengineering Central South University Changsha 410083 Hunan China

By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing （1 073- 1 323 K）. Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature （1073-1 173 K）. Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1 173-1 273 K. When oxidation temperature is higher than 1 273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-hearing magnetite pellet.

关键词： vanadium titanium-bearing magnetite oxidation degree pellet shrinking unreaeted-core model oxidation kinetics

Numerical investigation and modeling of sweep effects on inlet flow field of axial compressor cascades

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 296-308页

作者： Jiancheng zhang Donghai JIN Xingmin gui School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institue of Beihang University Nanchang 330096China

Swept blades are widely utilized in transonic compressors/fans and provide high load,high through-flow,high efficiency,and adequate stall ***,there is limited quantitative research on the mechanism of the effect of swept blades on the flow field,resulting in a lack of direct quantitative guidance for the design and analysis of swept blades in fans/*** better understand this mechanism,this study employs a reduced-dimensional force equilibrium method to analyze more than 1500 swept cascades *** verify that circumferential fluctuation terms are responsible for inducing radial migration in the inlet airflow field of the swept blade,resulting in variations in the incidence angle and consequently leading to changes in the characteristics of the swept ***,a combination of simple functions and machine learning is utilized to model the circumferential fluctuation terms and quantify the sweep *** prediction accuracy of the model is high,with coefficient of determination greater than 0.95 on the test *** the model is applied in a meridional flow analysis program,the calculation accuracy of the program for the incidence angle is improved by 0.4°and 0.6°at the design and off-design conditions respectively,compensating for the program’s original ***,the model can also provide quantitative guidance for the design of swept blades,thereby reducing the number of design iterations and improving design efficiency.

关键词： Turbomachinery Sweep aerodynamics Quasi-3D method Incidence angle Circumferential fluctuation Machine learning

Surface quality investigation in high-speed dry milling of Ti-6Al-4V by using 2D ultrasonic-vibration-assisted milling platform

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2024年第2期12卷 349-364页

作者： Jin zhang Li Ling Qian-Yue Wang Xue-Feng Huang Xin-Zhen Kang gui-Bao tao Hua-Jun Cao College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing400044People’s Republic of China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing400044People’s Republic of China Aerospace Research Institute of Materials and Processing Technology Beijing100076People’s Republic of China

Ultrasonic-vibration-assisted milling(UVAM)is an advanced method for the efficient and precise machining of difficult-to-machine materials in modern ***,the milling efficiency is limited because the ultrasonic vibration toolholder ER16 collet has a critical cutting ***,a 2D UVAM platform is built to ensure precision machining efficiency and improve the surface quality without changing the milling *** evaluate this 2D UVAM platform,ultrasonic-vibration-assisted high-speed dry milling(UVAHSDM)is performed to process a titanium alloy(Ti-6Al-4V)on the platform,and the milling temperature,surface roughness,and residual stresses are selected as the important indicators for performance *** results show that the intermittent cutting mechanism of UVAHSDM combined with the specific spindle speed,feed speed,and vibration amplitude can reduce the milling temperature and improve the texture of the machined *** with conventional milling,UVAHSDM reduces surface roughness and peak-groove surface profile values and extends the range of residual surface compressive stresses from−413.96 MPa to−600.18 *** excellent processing performance demonstrates the feasibility and validity of applying this 2D UVAM platform for investigating surface quality achieved under UVAHSDM.

关键词： 2D ultrasonic-vibration-assisted milling(UVAM)platform Ultrasonic-vibration-assisted high-speed dry milling(UVAHSDM) Milling temperature Surface roughness Residual stress

Deep guided Attention Network for Joint Denoising and Demosaicing in Real Image

维普期刊数据库评论

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 Electronics 2024年第1期33卷 303-312页

作者： tao zhang Ying FU Jun zhang School of Computer Science and Technology Beijing Institute of Technology Advanced Reasearch Institute of Multidisciplinary Science Beijing Institute of Technology

Denoising(DN) and demosaicing(DM) are the first crucial stages in the image signal processing pipeline. Recently, researches pay more attention to solve DN and DM in a joint manner, which is an extremely undetermined inverse problem. Existing deep learning methods learn the desired prior on synthetic dataset, which limits the generalization of learned network to the real world data. Moreover, existing methods mainly focus on the raw data property of high green information sampling rate for DM, but occasionally exploit the high intensity and signalto-noise(SNR) of green channel. In this work, a deep guided attention network(DGAN) is presented for real image joint DN and DM(JDD), which considers both high SNR and high sampling rate of green information for DN and DM, respectively. To ease the training and fully exploit the data property of green channel, we first train DN and DM sub-networks sequentially and then learn them jointly, which can alleviate the error accumulation. Besides, in order to support the real image JDD, we collect paired raw clean RGB and noisy mosaic images to conduct a realistic dataset. The experimental results on real JDD dataset show the presented approach performs better than the state-of-the-art methods, in terms of both quantitative metrics and qualitative visualization.

关键词： Training Visualization Inverse problems Green products Noise reduction Pipelines Signal processing

Association between antiplatelet medication and cerebral microbleeds in stroke-free population

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2022年第6期19卷 409-417页

作者： Miao-Xin YU Ya-Nan JIA Dan-Dan YANG Run-Hua zhang Yong JIANG gui-tao zhang Hui-Yu QIAO Hua-Lu HAN Rui SHEN Zi-Han NING Xi-Hai ZHAO Gai-Fen LIU Yong-Jun WANG Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Department of Neurology the Third Hospital of Hebei Medical UniversityShijiazhuangChina Department of Radiology Beijing Geriatric HospitalBeijingChina China National Clinical Research Center for Neurological Diseases BeijingChina Center for Biomedical Imaging Research Department of Biomedical EngineeringTsinghua UniversityBeijingChina Beijing Institute of Brain Disorders Capital Medical UniversityBeijingChina

BACKGROUND Cerebral microbleeds(CMBs)may increase the risk of future intracerebral hemorrhage and ischemic ***,It is unclear whether antiplatelet medication is associated with *** study aimed to investigate the association between antiplatelet medication and CMBs in a community-based stroke-free *** In this cross-sectional study,stroke-free participants aged 18-85 years were recruited from a community in Beijing,***,clinical,and antiplatelet medication data were collected through a questionnaire,and all participants underwent blood tests and brain magnetic resonance imaging at *** presence,count,and location of CMBs were evaluated using susceptibility-weighted *** association between antiplatelet medication and the presence of CMBs was analyzed using multivariable logistic *** associations between antiplatelet medication and CMBs by location(lobar,deep brain or infratentorial,and mixed regions)were also analyzed using multinomial logistic regression.A linear regression analysis was conducted to determine the association between antiplatelet medication and the log-transformed number of *** Of the 544 participants(mean age:58.65±13.66 years,217 males),119 participants(21.88%)had CMBs,and 64 participants(11.76%)used antiplatelet *** medication was found to be associated with CMBs at any location[odds ratio(OR)=2.39,95%CI:1.24-4.58]and lobar region(OR=2.83,95%CI:1.36-5.86),but not with the number of CMBs(β=0.14,95%CI:-0.21-0.48).Among antiplatelet medications,aspirin use was found to be associated with any CMB(OR=3.17,95%CI:1.49-6.72)and lobar CMBs(OR=3.61,95%CI:1.57-8.26).CONCLUSIONS Antiplatelet medication was associated with CMBs in stroke-free participants,particularly lobar *** antiplatelet medications,aspirin use was associated with any CMB and lobar *** findings suggest that it might be essential to optimize the management of antiplatelet medication in t

关键词： medication 3.0T antiplatelet

Neighbor Sum Distinguishing Total Choosability of Planar Graphs with Maximum Degree at Least 10

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第1期40卷 211-224页

作者： Dong-han zhang You Lu Sheng-gui zhang Li zhang School of Mathematics and Statistics Northwestern Polytechnical UniversityXi’an710129China School of Mathematics and Computer Application Shangluo UniversityShangluo726000China

A neighbor sum distinguishing(NSD)total coloringφof G is a proper total coloring of G such thatΣz∈EG(u)U{u}φ(z)≠Σz∈EG(v)U{v}φ(z)for each edge uv∈E(G),where EG(u)is the set of edges incident with a vertex *** 2015,Pilśniak and Wozniak conjectured that every graph with maximum degreeΔhas an NSD total(Δ+3)-***,Yang et *** that the conjecture holds for planar graphs withΔ≥10,and Qu et *** that the list version of the conjecture also holds for planar graphs withΔ≥*** this paper,we improve their results and prove that the list version of the conjecture holds for planar graphs withΔ≥10.

关键词： planar graphs neighbor sum distinguishing total choosibility combinatorial nullstellensatz discharging method

Holder continuous weak solutions of the 2D Boussinesq equation with thermal diffusion

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2024年第8期67卷 1777-1806页

作者： Tianwen Luo tao tao Liqun zhang Yau Mathematical Sciences Center Tsinghua UniversityBeijing 100084China School of Mathematics Shandong UniversityJinan 250100China Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

We show the existence of Holder continuous periodic weak solutions of the 2D Boussinesq equation with thermal diffusion which satisfy the prescribed kinetic *** precisely,for any smooth e(t):[0,1]→R+andε∈(0,110),there exist v∈C 110−ε([0,1]×T2)andθ∈C 1,120−εt 2 C 2,1 x 10−ε([0,1]×T2),which satisfy(1.1)in the sense of distribution and e(t)=ˆT2|v(t,x)|2 dx,∀t∈[0,1].

关键词： 2D Boussinesq equation with thermal diffusion Holder continuous periodic weak solutions prescribed kinetic energy

Competitive assembling strategy to construct carbon nitride homojunctions for boosting photocatalytic performance

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第5期172卷 23-32页

作者： Hua-Wei zhang Yuan-Yuan Li Bo Li Jing-Hui Shi tao Huang gui-Fang Huang Anlian Pan Wangyu Hu Wei-Qing Huang School of Physics&Electronic Engineering Zhengzhou University of Light IndustryZhengzhou 450002China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China College of Materials Science and Engineering Hunan UniversityChangsha 410082China

Both morphology and composition have a great influence on the properties and functions of materials,however,how to rational modulate both of them to achieve their synergistic effects has been a longstanding ***,we demonstrate a competitive assembling strategy for the construction of metal-free graphite carbon nitride(CN)homojunctions in which morphology and composition can be easily controlled simultaneously by only changing the ratio of assembly raw *** homojunctions are comprised of porous nanotubular S-doped CN(SCN)grafted with CN nanovesicles,which are derived from thermal polycondensation of melamine-thiocyanuric acid(M-T)/melamine-cyanuric acid(M-C)supramolecular hybrid *** unique architecture and component engineering endows the novel SCN-CN homojunction with abundant active sites,enhanced visible trapping ability,and intimate interface *** a result,the synthesized SCN-CN homojunctions demonstrate high photocatalytic activity for hydrogen evolution and pollutant *** developed strategy opens up intriguing opportu-nities for the rational construction of intricate metal-free heterostructures with controllable architecture and interfacial contact for applications in energy-related fields.

关键词： Competitive assembling strategy Supramolecular hybrid blocks Homojunctions Graphite carbon nitride Photocatalytic

Securing multi-chain consensus against diverse miner behavior attacks in blockchain networks

维普期刊数据库评论

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 Information Technology & Electronic Engineering 2024年第4期25卷 540-554页

作者： Wenbo zhang tao WANG Chaoyang zhang Jingyu FENG School of Cyberspace Security Xi’an University of Posts and TelecommunicationsXi’an 710121China Postal Savings Bank of China Xi’an 710000China

As cross-chain technologies enable interactions among different blockchains(hereinafter“chains”),multi-chain consensus is becoming increasingly important in blockchain ***,more attention has been paid to single-chain consensus ***-chain consensus schemes with trusted miner participation have not been considered,thus offering opportunities for malicious users to launch diverse miner behavior(DMB)attacks on different *** attackers can be friendly in the consensus process on some chains,called mask chains,to enhance their trust value,while on others,called kill chains,they engage in destructive behaviors on the *** this paper,we propose a multi-chain consensus scheme named Proof-of-DiscTrust(PoDT)to defend against DMB *** idea of distinctive trust(DiscTrust)is introduced to evaluate the trust value of each user across different *** trustworthiness of a user is split into local and global trust values.A dynamic behavior prediction scheme is designed to enforce DiscTrust to prevent an intensive DMB attacker from maintaining strong trust by alternately creating true or false blocks on the kill *** trusted miner selection algorithms for multi-chain environments can be implemented to select network miners,chain miners,and chain miner leaders,*** results show that PoDT is secure against DMB attacks and more effective than traditional consensus schemes in multi-chain environments.

关键词： Blockchain Cross-chain Trust mechanism Multi-chain consensus