检索结果-南通市图书馆

Efects of Rare Earth on Austenite–Ferrite Phase Transformation in a Low‑Carbon Fe–C Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2023年第1期36卷 141-146页

作者： Fei Guo Cheng‑Wu Zheng Pei Wang dian‑zhong Li Yi‑Y Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

The infuence of rare earth(RE)elements on austenite–ferrite phase transformation in Fe–0.14%C alloy has been investigated by in situ observing the nucleation,growth and morphology of ferrite using high temperature laser scanning confocal microscopy,and controlled atmosphere decarburization *** is found that under the low-oxygen condition in steel,trace RE addition can signifcantly infuence the nucleation,morphology and growth of ferrite in Fe–0.14%C alloy by the combined efects of RE slowing down the carbon difusion and decreasing grain boundary energy by segregating at grain *** research provides evidences of adjusting the phase transformation and improving the mechanical properties of steels by RE addition.

关键词： Steels Difusion Austenite-ferrite transformation Kinetics Rare earth

Sensor data compression based on MapReduce

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

The Journal of China Universities of Posts and Telecommunications 2014年第1期21卷 60-66页

作者： YU Yu GUO zhong-wen Department of Computer Science and Engineer Ocean University of China

A compression algorithm is proposed in this paper for reducing the size of sensor data. By using a dictionary-based lossless compression algorithm, sensor data can be compressed efficiently and interpreted without decompressing. The correlation between redundancy of sensor data and compression ratio is explored. Further, a parallel compression algorithm based on MapReduce [1] is proposed. Meanwhile, data partitioner which plays an important role in performance of MapReduce application is discussed along with performance evaluation criteria proposed in this paper. Experiments demonstrate that random sampler is suitable for highly redundant sensor data and the proposed compression algorithms can compress those highly redundant sensor data efficiently.

关键词： data compression sensor data MapReduce surveillance application measurement system

The nature of the γ-ray flare associated with blazar 3C 454.3

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2015年第9期15卷 1455-1466页

作者： wen Hu zhong-Hui Fan Ben-zhong Da Department of Astronomy Yunnan University Key Laboratory of Astroparticle Physics Yunnan Province

We have studied the simultaneous spectral energy distributions （SEDs） of the 2009 December flare and those of the quiescent state of blazar 3C 454.3 by con- structing a multi-component model We find that all six SEDs can be explained by a one-zone leptonic model involving synchrotron self-Compton （SSC） plus external Compton emission from an accretion disk （ECD） and that from a broad-line region （ECC）. X-ray emission is dominated by the SSC mechanism, and the γ-ray spectrum is well represented by a combination of ECD and ECC processes. Our results indicate that the energy density of the magnetic field and electrons decrease with distance from the central engine, and the Doppler factor increases with the blob moving outward in the development of the 2009 December flare. The increase in the observed flux density is possibly due to the increase in the Doppler factor of the blob. The relation between the Doppler factor σb and the distance from the central black hole suggests the magnetically driven jets span a sub-pc scale, and the relation between the magnetic field Bt and the dimension of the emission region R＇b is in good agreement with what is required by conservation of magnetic flux. The weak ＂harder-when-brighter＂ behavior of the γ-ray spectrum could be a result of the increase in Doppler factor during the outward motion of the blob. The parameters during the quiescent state obviously deviate from those during the flare state. We propose that the flare was likely caused by the ejection of a new blob. The gamma-ray emissions in different states are associated with the evolution of the blob.

关键词： radiation mechanisms: non-thermal -- methods: numerical -- galaxies:active -- quasars: individual (3C 454.3)

Anode material NbO for Li-ion battery and its electrochemical properties

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2018年第2期37卷 118-122页

作者： Jian Li wen-wen Liu Hong-Ming Zhou zhong-zhong Liu Bao-Rong Chen wen-Jiao Sun School of Materials Science and Engineering Central South UniversityChangsha 410083China Hunan Zhengyuan Institute for Energy Storage Materials and Devices Changsha 410083China

The NbO electrode materials were successfully synthesized by high-temperature solid-phase method using Nb powders and Nb2O5 powders as raw materials. The crystalline structure, morphology, and electrochemical properties of the obtained materials were characterized by X-ray diffi＇action （XRD）, scanning electron microscopy （SEM）, dynamic light scattering instrument （DLSA）, half- cell charge-discharge tests, and cyclic voltammetry （CV）. The reaction mechanism of lithium with NbO was inves- tigated by ex-situ XRD studies. The results show that material average Li storage voltage is nearly located at 1.6 V, and the lithium intercalation into NbO remains a single-phase process. For the first discharge, a capacity of 355 mAh·g^-1 is obtained at a current rate of 0.1C, and 293 mAh·g^-1is maintained after 50 cycles, whereas a capacity of 416 mAh·g^-1 is obtained at a current rate of 0.1C alter ball milling. And 380 mAh·g^-1 reversible capacity remains for the ball milling sample.

关键词： Niobium oxide Anode Electrochemicalproperties Lithium-ion batteries

Simplified Weighted Velocity Field for Prediction of Hot Strip Rolling Force by Taking into Account Flattening of Rolls

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第7期21卷 637-643页

作者： dian-hua ZHANG Jian-zhao CAO Jiu-jing XU wen PENG De-wen ZHAO State Key Laboratory of Rolling and Automation Northeastern University

The weighted velocity field was simplified for analysis of hot strip rolling. Using the field and GM （geometric midline） yield criterion, the deformation power, friction power and shear power were obtained respectively. Summing the partial power contributions, the total deformation power for strip rolling was presented. Then, by minimizing the power function, the rolling force was obtained; meanwhile, considering the effect of roll elastic flattening, iterative calculation of the roll radius was carried out until the radius was convergent. On line data were corn pared with the calculated results to verify the model accuracy. It was indicated that the calculated rolling forces were basically in agreement with the measured ones since the maximum error was less than 10.0%. Moreover, the effects of various rolling conditions such as thickness reduction, friction factor and shape factor, upon separating force, location of neutral angle, and stress state coefficient were discussed systematically.

关键词： hot strip rolling rolling force simplified weighted velocity field GM yield criterion elastic flattening analytical solution

Impact vibration properties of locally resonant fluid-conveying pipes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第12期29卷 313-321页

作者： Bing Hu Fu-Lei Zhu dian-Long Yu Jiang-Wei Liu Zhen-Fang Zhang Jie zhong Ji-Hong wen Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073China

Fluid-conveying pipe systems are widely used in various equipments to transport matter and *** to the fluid–structure interaction effect,the fluid acting on the pipe wall is easy to produce strong vibration and noise,which have a serious influence on the safety and concealment of the *** on the theory of phononic crystals,this paper studies the vibration transfer properties of a locally resonant(LR)pipe under the condition of fluid–structure *** band structure and the vibration transfer properties of a finite periodic pipe are obtained by the transfer matrix ***,the different impact excitation and fluid–structure interaction effect on the frequency range of vibration attenuation properties of the LR pipe are mainly considered and calculated by the finite element *** results show that the existence of a low-frequency vibration bandgap in the LR pipe can effectively suppress the vibration propagation under external impact and fluid impact excitation,and the vibration reduction frequency range is near the bandgap under the fluid–structure interaction ***,the pipe impact experiment was performed to verify the effective attenuation of the LR structure to the impact excitation,and to validate the finite element *** research results provide a technical reference for the vibration control of the fluid-conveying pipe systems that need to consider blast load and fluid impact.

关键词： locally resonant pipe fluid-structure interaction transfer matrix method impact vibration properties

Effect of Initial Crown on Shape of Hot Rolled Strip

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2009年第5期16卷 32-34页

作者： HU Yu GONG dian-yao JIANG Zheng-yi XU Jian-zhong ZHANG dian-hua LIU Xiang-hua State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 Liaoning China AriTime Co Ltd Beijing 100070 China Faculty of Engineering University of WoUongong Wollongong NSW 2522 Australia

Based on the influence coefficient method, the effect of entry strip crown on the shape of hot rolled strip was analyzed using the software of roll elastic deformation simulation. According to the practical condition of a domestic hot rolled strip plant, the unit strip crown change from the first stand to the last stand was calculated when the entry crown of hot strip varies. The calculated result shows that the entry strip crown does not significantly affect the target strip crown at the exit of the last finishing stand in respect to a fixed strip shape control reference （such as bending force）. The calculation was analyzed, and the research is helpful in modeling strip shape setup and shape control.

关键词： influence coefficient method strip crown crown effect rate hot rolled strip

Estimating Restricted Common Structural Changes for Panel Data

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2019年第4期35卷 893-908页

作者： Li-wen ZHANG zhong-yi ZHU School of Statistics and Management Shanghai University of Finance and Economics Shanghai 200444 China Department of Statistics School of Management Fudan University Shanghai 200433 China

We consider estimating multiple structural changes occurring at unknown common dates in a panel data regression model with restrictions imposed on the coefficients. We establish the consistency and rate of convergence of the structural change estimates and the asymptotic distribution of the parameter *** is shown that the efficiency of the parameter estimators is increased using the restrictions. An efficient dynamic algorithm is proposed to obtain the break date estimates and the parameter estimates. In addition, we propose a testing procedure for the existence of the change points with the restrictions and derive the asymptotic distribution under the null hypothesis of the test statistics. Simulation studies are presented to investigate the performance of the proposed method in finite samples.

关键词： common structural changes panel data consistency

Nitric oxide and calcium ions in apoptotic esophageal carcinoma cells induced by arsenite

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2002年第1期8卷 40-43页

作者： zhong-YingShen wen-YingShen 等 DepartmentofPathology DepartmentofChemistryMedicalCollegeofShantouNniversity Shantou515031GuangdongChina

AIM: To quantitatively analyze the nitric okide (NO) andCa2+ in apoptosis of esophageal carcinoma cells induced byarsenic trioxide (As2O3).METHODS: The cell line SHEEC1, a malignant esophagealepithelial call induced by HPV in synergy with TPA in ourlaboratory, was cultured in a serum-free medium and treatedwith As2O3. Before and after administration of As2O3, NOproduction in cultured medium was detected quantitativelyusing the Griess Colorimetric method. Intracellular Ca2+ waslabeled using the fluorescent dye Fluo3-AM and detectedunder confocal laser scanning microscope (CLSM), whichwas able to acquire data in real-time enabling Ca2+ dynamicsof individual cells in vitro. The apoptotic cells wareexamined under electron ***: Intracellular concentration of Ca2+ increased from1.00 units to 1.09-1.38 units of fluorescent intensity at As2O3treatment and NO products subsequently released fromAs2O3-treated cells increased from 0.98-1.00 × 10-2 mol@ L-1up to 1.48-1.52 × 10-2 mol@ L-1 and maintained in a highlevel contineously. Finally apoptosis of cells occurred,chromatin being agglutinated, cells shrunk, nuclei becameround and mitochondria ***:Ca2+ and NO increased with cell damage andapoptosis in cells treated by As2O3. The Ca2+ is an initialmessenger to the apoptotic pathway. To investigate Ca2+and NO will be a new direction for studying the apoptoticsignaling messenger of the esophageal carcinoma cellsinduced by As2O3.

关键词：亚砒酸盐食管癌氮氧化物钙离子细胞凋亡