检索结果-南通市图书馆

Design for Isothermal Forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第8期17卷 67-73页

作者： SI Jia-yong han Peng-biao ZhanG Ji Institute of Processing Technologies of Materials Central South University of Forestry and TechnologyChangsha 410004HunanChina High Temperature Material Research Division Central Iron andSteel Research InstituteBeijing 100081China

The three-dimensional finite element method was utilized to investigate the isothermal forging of Ti-46.5Al-2.5V-1.0Cr-0.3Ni（atomic percent,%）*** partition of height reduction,effective strain,and damage of the alloy during the forging were *** simulation results were verified by *** results show that large plastic deformation can improve the homogeneity of the deformed microstructure and the higher accumulative height reduction can be achieved through two-step *** the isothermal forging of two-step reduction of 60%＋62.5%（total height reduction of 85%）,the entire forged pancake can acquire refined microstructure and expand the uniform flow zone to almost the entire volume.

关键词： titanium aluminide isothermal forging multistep forging FEM simulation

A Direct Algorithm Maple Package of One-Dimensional Optimal System for Group Invariant Solutions

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第1期69卷 14-22页

作者： Lin Zhang Zhong han yong Chen Shanghai Key Laboratory of Trustworthy Computing East China Normal UniversityShanghai 200062China Department of Physics Zhejiang Normal UniversityJinhua 321004China

To construct the one-dimensional optimal system of finite dimensional Lie algebra automatically,we develop a new Maple package One Optimal ***,we propose a new method to calculate the adjoint transformation matrix and find all the invariants of Lie algebra in spite of Killing form checking possible constraints of each ***,a new conception called invariance set is ***,this Maple package is proved to be more efficiency and precise than before by applying it to some classic examples.

关键词： symbolic computation mathematics mechanization direct algorithm optimal system

Effects of rainfall regime and its character indices on soil loss at loessial hillslope with ephemeral gully

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2017年第3期14卷 527-538页

作者： han yong ZHENG Fen-li XU Xi-meng State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau Institute of Soil and Water ConservationChinese Academy of SciencesYangling 712100China University of Chinese Academy of Sciences Beijing 100049China Institute of Soil and Water Conservation NorthwestA&F UniversityYangling 712100China

Understanding the relationship between hillslope soil loss with ephemeral gully and rainfall regime is important for soil loss prediction and erosion control. Based on 12-year field observation data, this paper quantified the rainfall regime impacts on soil loss at loessial hillslope with ephemeral gully. According to three rainfall parameters including precipitation （P）, rainfall duration （t）, and maximum 30-minute rainfall intensity （I30）, 115 rainfall events were classified by using K-mean clustering method and Discriminant Analysis. The results showed that 115 rainfall events could be divided into three rainfall regimes. Rainfall Regime 1 （RR1） had large I30 values with low precipitation and short duration, while the three rainfall parameters of Rainfall Regime 3 （RR3） were inversely different compared with those of RR1; for Rainfall Regime 2 （RR2）, the precipitation, duration and Iso values were all between those of RR1 and RR3. Compared with RR2 and RR3, RR1 was the dominant rainfall regime for causing soil loss at the loessial hillslope with ephemeral gully, especially for causing extreme soil loss events. PI30 （Product of P and Izo） was selected as the key index of rainfall characteristics to fit soil loss equations. Two sets of linear regression equations between soil loss and Plzo with and without rainfall regime classification were fitted. Compared with the equation without rainfall regime classification, the cross validation results of the equations with rainfall regime classification was satisfactory. These results indicated that rainfall regime classification could not only depict rainfall characteristics precisely, but also improve soil loss equation prediction accuracy at loessial hillslope with ephemeral gully.

关键词： Rainfall regime Soil loss Rainfall character indices Loessial hillslope Ephemeral gully

TYRE DYNAMICS MODELLING OF VEHICLE BASED ON SUPPORT VECTOR MACHINES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2006年第4期19卷 558-565页

作者： ZHENG Shuibo TANG Houjun han Zhengzhi ZhanG yong School of Electronic Information and Electrical Engineering Shanghai Jiaotong University Shanghai 200030 China Institute of Automotive Engineering Shanghai Jiaotong University Shanghai 200030 China

Various methods of tyre modelling are implemented from pure theoretical to empirical or semi-empirical models based on experimental results. A new way of representing tyre data obtained from measurements is presented via support vector machines （SVMs）. The feasibility of applying SVMs to steady-state tyre modelling is investigated by comparison with three-layer backpropagation （BP） neural network at pure slip and combined slip. The results indicate SVMs outperform the BP neural network in modelling the tyre characteristics with better generalization performance. The SVMsqyre is implemented in 8-DOF vehicle model for vehicle dynamics simulation by means of the PAC 2002 Magic Formula as reference. The SVMs-tyre can be a competitive and accurate method to model a tyre for vehicle dynamics simuLation.

关键词： Support vector machines(SVMs) Backpropagation(BP) neural network Tyre model Regression estimation Magic formula

Effective Activation of Melamine for Synchronous Synthesis of Catalytically Active Nanosheets and Fluorescence-Responsive Quantum Dots

在线全文

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2024年第3期30卷 284-296页

作者： Jie Xuan Guijian Guan Ming-yong han Institute of Molecular Plus Tianjin UniversityTianjin 300072China

Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior *** this study,we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation,which eff ectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets(CCN NSs)during hydrothermal *** a large specific surface area and increased light absorption,these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO_(2) reduction,increasing the CO production rate by approximately tenfold compared with hexagonal melamine(h-Me).Moreover,the product selectivity of CCN NSs reaches up to 93.5%to generate CO from CO_(2).Furthermore,the annealed CCN NSs exhibit a CO conversion rate of up to 95.30μmol/(g h),which indicates an 18-fold increase compared with traditional carbon *** the CCN NS synthesis,nitrogen-doped carbon quantum dots(NDC QDs)are simultaneously produced and remain suspended in the supernatant after *** QDs disperse well in water and exhibit excellent luminescent properties(QY=67.2%),allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04μmol/***,the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-eff ective and highly efficient process,yielding products with superior capabilities for catalytic conversion of CO_(2) and pollutant detection,respectively.

关键词： Carbon nitride Hydrothermal reaction Photocatalysis Carbon dioxide Quantum dots

Sources of nitrous and nitric oxides in paddy soils: Nitrification and denitrification

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第3期26卷 581-592页

作者： Ting Lan yong han Marco Roelcke Rolf Nieder Zucong Cai State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Institute of Geoecology Technische Universitt Braunschweig School of Geography Sciences Nanjing Normal University

Rice-paddies are regarded as one of the main agricultural sources of N 2O and NO emissions. To date, however, specific N2O and NO production pathways are poorly understood in paddy soils. ^15N-tracing experiments were carded out to investigate the processes responsible for N2O and NO production in two paddy soils with substantially different soil properties. Laboratory incubation experiments were carried out under aerobic conditions at moisture contents corresponding to 60% of water holding capacity. The relative importance of nitrification and denitrification to the flux of NaO was quantified by periodically measuring and comparing the enrichments of the N2O, NH^-N and NO3-N pools. The results showed that both N2O and NO emission rates in an alkaline paddy soil with clayey texture were substantially higher than those in a neutral paddy soil with silty loamy texture. In accordance with most published results, the ammonium N pool was the main source of N2O emission across the soil profiles of the two paddy soils, being responsible for 59.7% to 97.7% of total N2O emissions. The NO3-N pool of N2O emission was relatively less important under the given aerobic conditions. The rates of N2O emission from nitrification （N2On） among different soil layers were significantly different, which could be attributed to both the differences in gross N nitrification rates and to the ratios of nitrified N emitted as NzO among soil layers. Furthermore, NO fluxes were positively correlated with the changes in gross nitrification rates and the ratios of NO/N2O in the two paddy soils were always greater than one （from 1.26 to 6.47）. We therefore deduce that, similar to N2O, nitrification was also the dominant source of NO in the tested paddy soils at water contents below 60% water holding capacity.

关键词： ^15N tracing model N2O NO NO/N2O nitrification denitrification

New probabilistic transformation of imprecise belief structure

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2011年第5期22卷 721-729页

作者： Lifang Hu You He Xin Guan Deqiang han yong Deng Research Institute of Information Fusion Naval Aeronautical and Astronautical University Yantai 264001 E R. China Navy Armament Academy Beijing 102249 E R. China College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 E R. China Institute of Integrated Automation Xi＇an Jiaotong University Xi＇an 710049 E R. China School of Electronics and Information Technology Shanghai Jiaotong University Shanghai 200240 E R. China

The case when the source of information provides precise belief function/mass, within the generalized power space, has been studied by many people. However, in many decision situations, the precise belief structure is not always available. In this case, an interval-valued belief degree rather than a precise one may be provided. So, the probabilistic transformation of imprecise belief function/mass in the generalized power space including Dezert-Smarandache （DSm） model from scalar transformation to sub-unitary interval transformation and, more generally, to any set of sub-unitary interval transformation is provided. Different from the existing probabilistic transformation algorithms that redistribute an ignorance mass to the singletons involved in that ignorance pro- portionally with respect to the precise belief function or probability function of singleton, the new algorithm provides an optimization idea to transform any type of imprecise belief assignment which may be represented by the union of several sub-unitary （half-） open intervals, （half-） closed intervals and/or sets of points belonging to [0,1]. Numerical examples are provided to illustrate the detailed implementation process of the new probabilistic transformation approach as well as its validity and wide applicability.

关键词： pignistic probability transformation generalized power space interval value information fusion uncertainty.

Identification of injury type using somatosensory and motor evoked potentials in a rat spinal cord injury model

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2023年第2期18卷 422-427页

作者： Rong Li han-Lei Li Hong-Yan Cui yong-Can Huang yong Hu Department of Orthopedics and Traumatology The University of Hong Kong-Shenzhen HospitalShenzhenGuangdong ProvinveChina Department of Neurosurgery Neuroscience CenterIntegrated Hospital of Traditional Chinese MedicineSouthern Medical UniversityGuangzhouGuangdong ProvinveChina Institute of Biomedical Engineering Chinese Academy of Medical Sciences and Peking Union Medical CollegeTianjinChina Shenzhen Engineering Laboratory of Orthopedic Regenerative Technologies Department of Spine SurgeryPeking University Shenzhen HospitalShenzhenGuangdong ProvinveChina Department of Orthopedics and Traumatology The University of Hong KongPokfulamHong Kong Special Administrative RegionChina

The spinal cord is at risk of injury during spinal *** intraoperative spinal co rd injury is identified early,irreve rsible impairment or loss of neurological function can be *** types of spinal cord injury result in damage to diffe rent spinal cord regions,which may cause diffe rent somatosensory and motor evoked potential signal res *** this study,we examined electrophysiological and histopathological changes between contusion,distra ction,and dislocation spinal cord injuries in a rat *** found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked *** resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal *** amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by *** distraction injury,extracellular spaces were slightly but not significantly enlarged;somatosensory evoked potential res ponses slightly decreased and motor evoked potential responses were *** analysis showed that histological and electrophysiological findings we re significantly correlated and related to injury *** rative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

关键词： contusion injury dislocation injury distraction injury electropnysiology heterogeneity histopathology injury mechanism motor evoked potential somatosensory evoked potential spinal cord injury

Broken Rotor Bar Fault Detection of Induction Motors Using a Joint Algorithm of Trust Region and Modified Bare-bones Particle Swarm Optimization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2019年第1期32卷 65-78页

作者： Panpan Wang Liping Shi yong Zhang Yifan Wang Li han School of Electrical and Power Engineering China University of Mining & Technology

A precise detection of the fault feature parameter of motor current is a new research hotspot in the broken rotor bar(BRB) fault diagnosis of induction motors. Discrete Fourier transform(DFT) is the most popular technique in this field, owing to low computation and easy realization. However, its accuracy is often limited by the data window length, spectral leakage, fence e ect, etc. Therefore, a new detection method based on a global optimization algorithm is proposed. First, a BRB fault current model and a residual error function are designed to transform the fault parameter detection problem into a nonlinear least-square problem. Because this optimization problem has a great number of local optima and needs to be resolved rapidly and accurately, a joint algorithm(called TR-MBPSO) based on a modified bare-bones particle swarm optimization(BPSO) and trust region(TR) is subsequently proposed. In the TR-MBPSO, a reinitialization strategy of inactive particle is introduced to the BPSO to enhance the swarm diversity and global search ability. Meanwhile, the TR is combined with the modified BPSO to improve convergence speed and accuracy. It also includes a global convergence analysis, whose result proves that the TR-MBPSO can converge to the global optimum with the probability of 1. Both simulations and experiments are conducted, and the results indicate that the proposed detection method not only has high accuracy of parameter estimation with short-time data window, e.g., the magnitude and frequency precision of the fault-related components reaches 10^(-4), but also overcomes the impacts of spectral leakage and non-integer-period sampling. The proposed research provides a new BRB detection method, which has enough precision to extract the parameters of the fault feature components.

关键词： Fault detection Broken rotor bars Induction motors Bare-bones particle swarm optimization Trust region