检索结果-南通市图书馆

Relationship between single and bulk mechanical properties for zeolite ZSM5 spray-dried particles

在线全文

学校读者我要写书评

暂无评论

Particuology 2014年第3期12卷 130-138页

作者： M.Marigo D.L.Cairns J.Bowen A.Ingram E.h.Stitt Johnson Matthey Technology Centre P.O.Box 1Belasis AvenueBillinghamCleveland TS23 1LBUnited Kingdom Centre for Formulation Engineering Chemical EngineeringSchool of EngineeringThe University of BirminghamB15 2TTUnited Kingdom

In this work typical mechanical properties for a catalyst support material, ZSM5 （a spray-dried granular zeolite）, have been measured in order to relate the bulk behaviour of the powder material to the single particle mechanical properties. Particle shape and size distribution of the powders, determined by laser diffraction and scanning electron microscopy （SEM）, confirmed the spherical shape of the spray-dried particles. The excellent flowability of the material was assessed by typical methods such as the hausner ratio and the Cart index, This was confirmed by bulk measurements of the particle-particle internal friction parameter and flow function using a Schulze shear cell, which also illustrated the low compressibility of the material. Single particle compression was used to characterize single particle mechanical properties such as reduced elastic modulus and strength from hertz contact mechanics theory. Comparison with surface properties obtained from nanoindentation suggests heterogeneity, the surface being harder than the core. In order to evaluate the relationship between single particle mechanical properties and bulk compression behaviour, uniaxial confined compression was carried out. It was determined that the Adams model was suitable for describing the bulk compression and furthermore that the Adams model parameter, apparent strength of single particles, was in good agreement with the single particle strength determined from single particle compression test.

关键词： Zeolite particle Flowability Powder flow function Effective angle of internal friction Schulze shear cell Nanoindentation Single particle compression Bulk compression

Synthesis and characterization of lithium niobium borate glasses containing neodymium

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2016年第12期34卷 1199-1205页

作者： W.h.A.Kamaruddin M.S.Rohani M.R.Sahar LIU hong SANG Yuanhua AOMRG Lab Physics Department Faculty of Science Universiti Teknologi Malaysia State Key Laboratory of Crystal Materials Shandong University

A series of（90–x）Li2B4O7-10Nb2O5-xNd2O3 glass samples（x=0, 5 mol.%, 10 mol.%, 15 mol.%, 20 mol.% and 25 mol.%） were synthesized using melt quenching technique. X-ray diffraction（XRD）, differential thermal analyzer（DTA）, Fourier transformed infrared（FTIR）, ultraviolet-visible-near-infrared（UV-Vis-NIR） spectrometer and photoluminescence（PL） spectroscopic characterizations were made to examine the influence of Nd3＋ concentration on the physical, structural and optical properties. Various physical properties such as glasses density, molar volume, thermal stability, ion concentration, polar on radius, inter-nuclear distance, field strength, cut-off wavelength, energy band gap and Urbach energy were calculated. The samples were amorphous in nature and confirmed from XRD pattern. The FTIR spectra revealed the presence of BO3 and BO4 functional groups. UV-Vis-NIR spectra exhibited nine prominent bands centered at 353, 430, 475, 524, 583, 681, 745, 803, 875 nm corresponding to the transitions from the ground state to ^4D（3/2）, ^2P（1/2）, ^2G（9/2）, ^4G（7/2）, ^4G（5/2）, ^4F（9/2）, ^4F（7/2）, ^4F（5/2）, ^4F（3/2） excited states, respectively. Moreover, the emission spectra at 355 nm excitation displayed three peaks centered at 903 nm（^4F（3/2）→^4I（9/2））, 1059 nm（^4F（3/2）→^4I（11/2）） and 1333 nm（^4F（3/2）→^4I（13/2））, respectively. Fluorescence lifetime was recorded between 53.69 to 28.43 μs. It was found that varying concentration of Nd^（3＋） ions strongly affected the physical, structural and optical properties of the glass samples.

关键词： borate glass neodymium optical properties band gap luminescence rare earths

Multiple radial phosphorus segregations in GaAsP core-shell nanowires

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第1期14卷 157-164页

作者： h.Aruni Fonseka Yunyan Zhang James A.Gott Richard Beanland huiyun Liu Ana M.Sanchez Department of Physics University of WarwickCoventry CV47ALUK Department of Electronic and Electrical Engineering University College LondonLondon WC1E 7JEUK

highly faceted geometries such as nanowires are prone toform self-formed features,especially those that are driven by *** these features is important in preventing their formation,understanding their effects on nanowire properties,or engineering them for *** elemental segregation lines that run along the radii of the hexagonal cross-section have been a common observation in alloy semiconductor ***,in GaAsP nanowires,two additional P rich bands are formed on either side of the primary band,resulting in a total of three segregation bands in the vicinity of three of the alternating *** bands are less intense than the primary band and their formation can be attributed to the inclined nanofacets that form in the vicinity of the *** formation of the secondary bands requires a higher composition of P in the shell,and to be grown under conditions that increase the diffusivity difference between As and ***,it is observed that the primary band can split into two narrow and parallel *** can take place in all six radii,making the cross sections to have up to a maximum of 18 radial segregation *** controlled growth,these features could be exploited to assemble multiple different quantum structures in a new dimension(circumferential direction)within nanowires.

关键词： compound semiconductor alloys radial segregations three-fold symmetry surface chemical potential

MEChANICAL PROPERTIES OF LONGITUDINAL SUBMERGED ARC WELDED STEEL PIPES USED FOR GAS PIPELINE OF OFFShORE OIL

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

Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 85-93页

作者： Z.Z. Yang W. Tian Q.R. Ma Y.L. Li J.K. Li J.Z. Gao h.B. Zhang Y.h. Yang Tubular Goods Research Center of CNPC Xi＇an 710065 China Xiran Aerotechnical College Xi＇an 710077 China

Since the development of offshore oil and gas, increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipelines depended on importing because of the strict requirements of comprehensive properties, such as, anti-corrosion, resistance to pressure and so on. To research and develop domes- tic steel pipes used for the submarine pipeline, the Longitudinal-seam Submerged Arc Welded （LSAW） pipes were made of steel plates cut from leveled hot rolled coils by both the JCOE and UOE （the forming process in which the plate like the letter “J”, “C”, “0” or “U” shape, then expansion） forming processes. Furthermore, the mechanical properties of the pipe base metal and weld metal were tested, and the results were in accordance with the corresponding pipe specification API SPEC 5L or DNV- OS-FI01, which showed that domestic LSAW pipes could be used for submarine oil and gas pipelines.

关键词： Mechanical properties Offshore oil and gas Longitudinal-seamsubmerged arc welded pipe (LSA W) Pipeline JCOE formingprocess UOE forming process

Mechanical properties of steel, glass, and hybrid fiber reinforced reactive powder concrete

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第4期13卷 998-1006页

作者： Atheer h. M. ALGBURI M. Neaz ShEIKh Muhammad N. S. hADI School of Civil Mining and Environmental Engineering University of Wollongong NSW 2522 Australia

This study examines the properties of fiber-reinforced reactive powder concrete (FR-RPC). Steel fibers, glass fibers, and steel-glass hybrid fibers were used to prepare the FR-RPC. The non-fibrous reactive powder concrete (NF-RPC) was prepared as a reference mix. The proportion of fibers by volume for all FR-RPC mixes was 1.5%. Steel fibers of 13 mm length and 0.2 mm diameter were used to prepare the steel fiber-reinforced RPC (SFR-RPC). Glass fibers of 13 mm length and 1.3 mm diameter were used to prepare the glass fiber-reinforced RPC (GFR-RPC). The hybrid fiber-reinforced RPC (hFR-RPC) was prepared by mixing 0.9% steel fibers and 0.6% glass fibers. Compressive strength, axial load-axial deformation behavior, modulus of elasticity, indirect tensile strength, and shear strength of the RPC mixes were investigated. The results showed that SFR-RPC achieved higher compressive strength, indirect tensile strength and shear strength than NF-RPC, GFR-RPC, and hFR-RPC. Although the compressive strengths of GFR-RPC and hFR-RPC were slightly lower than the compressive strength of NF-RPC, the shear strengths of GFR-RPC and hFR-RPC were higher than that of NF-RPC.

关键词： reactive powder concrete steel fiber glass fiber hybrid fiber

Petroleum heteroatom compounds in various commercial delayed coking liquids： characterized by FT-ICR MS and GC techniques

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

Science China Chemistry 2017年第2期60卷 284-292页

作者： Miao hu Chuang Guo Linzhou Zhang Suoqi Zhao Keng h. Chung Chunming Xu Quan Shi State Key Laboratory of heavy Oil Processing China University of Petroleum Beijing 102249 China Daqing Oilfield Limited Corporation Daqing 163159 China North huajin Chemical Industries Group Corporation Panjin 124000 China

Delayed coking is an important petroleum resid conversion *** processability of coking liquids is known to be dependent on the heteroatom compounds present in the coking *** commercial delayed coking liquids were characterized by electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(ESI FT-ICR MS)and gas chromatographic *** relatively abundant heteroatom compounds in the coking liquids were 1-4 aromatic-ring pyridinic nitrogen compounds,carbazoles,benzocarbazoles,phenols,mercaptans,benzothiophenes,dibenzothiophenes,and *** liquids derived from various feeds had similar compound class types,molecular weight distribution ranges,and double bond equivalents(DBE).however,the concentration of individual compounds and the distribution of DBE versus carbon number of heteroatom compounds varied.A comparison of heteroatom compounds in coker feeds and products revealed the various reaction mechanism of heteroatom compounds occurred during the coking *** results suggested that molecular-level process models can be developed for optimization of unit operation to obtain desirable products that meet the environmental specifications and quality requirements.

关键词： FT-ICR MS molecular composition heteroatom compounds petroleum delayed coking

Experimental studies and phase field modeling of microstructure evolution during solidification with electromagnetic stirring

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2010年第S3期20卷 774-780页

作者： P.GERALD TENNYSON P.KUMAR h.LAKShMI G.PhANIKUMAR P.DUTTA Department of Metallurgical and Materials Engineering Indian Institute of Technology National Facility for Semisolid Forming Department of Mechanical EngineeringIndian Institute of Science

Thixocasting requires manufacturing of billets with non-dendritic *** alloy A356 billets were produced by rheocasting in a mould placed inside a linear electromagnetic *** heat treatment was used to produce a transition from rosette to globular *** current and the duration of stirring were explored as control *** induction heating of the billet during stirring was quantified using experimentally determined thermal *** effect of processing parameters on the dendrite fragmentation was *** computational modeling of the process was performed using phase-field modeling of alloy solidification in order to gain insight into the process of morphological changes of a solid during this process.A non-isothermal alloy solidification model was used for *** morphological evolution under such imposed thermal cycles was simulated and compared with experimentally determined *** scaling using the thermosolutal diffusion distances was used to overcome computational difficulties in quantitative comparison at system *** results were interpreted in the light of existing theories of microstructure refinement and globularisation.

关键词： electromagnetic stirring non-dendritic phase field modeling microstructure

A multi-objective pigeon inspired optimization algorithm for fuzzy production scheduling problem considering mould maintenance

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2019年第7期62卷 15-32页

作者： Xiaoyue FU Felix T.S.ChAN Ben NIU Nick S.h.ChUNG Ting QU Department of Industrial and Systems Engineering The Hong Kong Polytechnic University College of Management Shenzhen University School of Electrical and Information Engineering Jinan University

The fuzzy production scheduling problem considering mould maintenance(FPSP-MM) is studied. The processing time and the maintenance time are represented by triangular fuzzy numbers. When tasks are executed based on the sequence provided by the fuzzy schedule, the real duration of each task needs to be known so the posteriori solution with deterministic processing times can be obtained. Therefore, the concept of the schedule robustness needs to be considered for the fuzzy problem. The robustness is considered as the optimization objective except for the fuzzy makespan in this research. To optimize these two objective functions, a multi-objective pigeon inspired optimization(MOPIO) algorithm is developed. To extend the pigeon inspired optimization(PIO) algorithm from the single-objective case to the multi-objective case, nondominated solutions are used as candidates for the leader pigeon designation and a special crowding distance is used to ensure a good distribution of solutions in both the objective space and the corresponding decision space. Furthermore, an index-based ring topology is used to manage the convergence speed. Numerical experiments on a variety of simulated scenarios show the excellent efficiency and effectiveness of the proposed MOPIO algorithm by comparing it with other algorithms.

关键词： fuzzy production scheduling mould maintenance pigeon inspired optimization multi-objective

Evidence of advancing spring xylem phenology in Chinese forests under global warming

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2023年第10期66卷 2187-2199页

作者： huihong XUE Feng ShI Fabio GENNARETTI Yongshuo h.FU Bin hE Xiuchen WU Zhengtang GUO Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China CAS Center for Excellence in Life and Paleoenvironment Beijing100044China Institut de Recherche sur les Forêts Groupe de Recherche enÉcologie de la MRC-AbitibiUniversitédu Québec en Abitibi-TémiscamingueAmosJ9T 2L8Canada College of Water Sciences Beijing Normal UniversityBeijing100875China Faculty of Geographical Science Beijing Normal UniversityBeijing100875China

Phenological responses of vegetation to the ongoing warming trend impact current and future primary ***,few studies focus on wood phenology because its observed data are much scarcer,which hinders the estimation and prediction of forest carbon budgets over large ***,we use a physiological process-based tree-ring growth model(Vaganov-Shashkin model)to investigate the spatial and temporal variations of spring xylem phenology(start of the growing season of xylem,SOS_(x))in tree-ring sites of China during 1962-2016 *** model is calibrated on measured tree-ring width chronologies(70 tree-ring chronologies)and successfully validated with field observations of *** found that spring xylem phenology significantly advances during 1962-2016 CE period under global warming,with the rate of advance quickly increasing after the 1990s to an average of 0.25 days per *** preseason daily mean temperature is the main climatic driver for spring xylem phenology as indicated by its significant correlations with SOS_(x)at most sites(71%).Warmer preseason allows heat requirements for tree growth to be reached more quickly,with increase of 1℃in temperature of preseason anticipates SOS_(x)by 6 to 7 days,which will benefit the radial growth of trees in the relatively cold-humid *** addition,the significant positive correlation between the simulated spring xylem phenology and remote sensing derived phenology highlights the primary and secondary growth may be governed by the same variable(temperature)and change in the same direction with global *** study provides the long-term perspective on the spring xylem phenology variations covering most of China.

关键词： Tree-ring Xylem Phenology Vaganov-Shashkin model China