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Journal of Rare Earths 2024年第7期42卷 1240-1249,I0002页

作者： Ziyao Wang haitao Fu Xiufeng Zhan Bo tong Guofeng Ma h.t.(Bert)hintzen Institute of Innovative Science and technology Shenyang UniversityShenyang110044China College of Mechanical Engineering Shenyang UniversityShenyang110044China Faculty of Applied Sciences Delft University of Technology2629 JBDelftthe Netherlands

A novel Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state *** valence state of Eu,ph.t.luminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and *** phosphor shows high sensitivity(Sa=0.0173 K^(-1),S_(r)=0.461%/K)and superior signal discriminability(Δν∼10380 cm^(−1)).the thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu^(2+)versus Eu^(3+)combined with energy transfer from Eu^(2+)to Eu^(3+),so th.t.the sensitivity of the phosphor in the temperature range presents a non-monotonic *** development of the BaAl_(2)B_(2)O_(7):Eu^(2+),Eu^(3+)phosphor is not only expected to be relevant for application in the field of temperature sensing,but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu^(2+)-Eu^(3+)co-activated ratiometric thermo-sensitive phosphors.

关键词： Ph.t.luminescence Ratiometric thermo-response Phosphor Eu^(2+)/Eu^(3+) Rare earths

Exploring trees Diversity and Ecological Value of Mountain Forests in the Blue Nile Region of Sudan

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Open Journal of Ecology 2024年第3期14卷 245-256页

作者： Dafa-Alla M. Dafa-Alla haytham h. Gibreel Ahmed A. h. Siddig Yousif E. Yagoub hashim A. Abdelkarim Kh.t.r h.t. Saeed Ahmed I. Abuelbashar Faculty of Forestry-Shambat University of Khartoum Khartoum Sudan harvard Forest Harvard University Petersham MA USA Faculty of Forest Science and Wood technology University of Gezira Wad-Medani Sudan Department of Forestry and Range Sciences Faculty of Natural Resources and Environmental Studies Alsalam University Alfula Sudan Forest Research and Gum Arabic Centre Agricultural Research Corporation Khartoum-Soba Sudan

We carried out this research at Abu-Gaddaf Natural Forest Reserve (ANFR) which is located east of Blue Nile River, in Blue Nile State, Sudan. It aims at exploring tree composition assessing their diversity indices, and ecological importance values. For survey of types and estimation of density of tree species in the forest, we randomly distributed 97 circular sample plots (0.1 hectare (ha)). In each sample plot we identified all trees to the species level, recorded their frequencies and computed species diversity and importance value indices (IVI). A total of 13 tree species, which belong to 12 genera and nine families, were identified in the tree layer of the forest. Mean tree density in ANFR was 116 trees/ha, composed mainly of Boswellia papyrifera (Del.) hoch.t. (48), followed by Combretum hartmannianu (19) and Lannea fruticosa (18). Fabaceae was the most common family followed by Combretaceae and Malvaceae. B. papyrifera Delile hoch.t.was the most abundant while Acacia seyal was the least abundant species. Species richness (R = 1.71), evenness (E = 0.69), dominance (0.24) indices and Simpson’s Index of Diversity (D' = 0.76) suggest a moderate diversity, moderate numbers of individuals in each species and a moderate community stability. the research provides empirical results on diversity and ecological importance value of species, signifies the urging need to safeguard threatened species and to prioritize them for conservation, as well as the need to promote management of abundant species to provide multiple forest ecosystem services.

关键词： tree Species Diversity Dry-Land Forest Sudan

Design to reduce electromagnetic vibration in integral-slot SPM machine considering force modulation effect

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Science China(technological Sciences) 2022年第8期65卷 1867-1877页

作者： ZhU ShengDao ZhAO WenXiang JI Jinghua LIU Guohai LEE Christopher h.t. School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

In this paper, two different designs, with dummy slots and bread-loaf magnets techniques, are presented to reduce the electromagnetic vibration in integral-slot surface-mounted permanent-magnet(SPM) machines. Firstly, the stator slotting effect on the magnetic field modulation and radial force modulation is investigated. It reveals the amplitude of the modulated magnetic field and modulated radial force is greatly affected by the slot opening effect, while the spatial order is closely associated with.t.e slot numbers. Subsequently, the dummy slots and bread-loaf magnets design are developed for a 36-slot/12-pole integral-slot SPM machine to reduce the electromagnetic vibration. Finally, two SPM machines, with conventional and bread-loaf magnets,are manufactured. Experimental tests are carried out to validate the theoretical analyses.

关键词： surface-mounted permanent-magnet machine slot opening width dummy slots bread-loaf magnets vibration reduction

Chaotic movement of vortices in superconductors of high.t.c superconducting maglev system at a high speed

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Journal of Modern transportation 2012年第2期20卷 70-75页

作者： h.t. LIN Department of Information Management Department of Electrical Engineering Cheng Shiu University Taiwan China

Vortex motion in superconductors of high.t. superconducting maglev system is studied by a computational simulation. the vortex system is treated in a similar fashion, as a system where defects are arranged in periodic arrays and driven by an alternating current （AC） field. Computational simulation reveals th.t.due to the high nonlinearity of the vortex-defect interaction, the system shows typical chaotic characters. Effects of the vortex-vortex coupling, the driving frequency, and the vortex viscosity on the vortex motion have been studied to reveal the interaction between the spatial and temporal chaos. It is found th.t.the mean-field approach is a good approximation to describe the vortex motion in one dimensional vortex system under an AC driving field. the vortex motion under the damping mode is a kind of self-organized motion. Lastly, the spatial chaos can dominate the chaotic behavior of the system.

关键词： superconductors vortex motion spatial chaos temporal chaos

First-Principle Calculations of hardness and Melting Point of Mo_2C

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Journal of Materials Science & technology 2009年第3期25卷 419-422页

作者： X.R. Wang M.F. Yan h.t. Chen School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

this paper has constructed two kinds of atomic and electronic models for hexagonal β-Mo2C and orthorhombic α-Mo2C. the optimized lattice parameters, elastic constant matrixes and overlap population for Mo2C crystal cells have been obtained to realize the characterization of the hardness and melting point of the two structures by the first-principles plane wave pseudo potential method based on the density functional theory. the results reveal th.t.the calculated lattice parameters of the Mo2C crystal cells agree with.t.e experimental and other calculated data. the calculated melting point/hardness are 2715 K/11.38 GPa for β-Mo2C and 2699 K/10.57-12.67 GPa for α-Mo2C, respectively. the calculated results from the density of states （DOS） demonstrate th.t.the hybridization effect between Mo-3d and C-2p states in α-Mo2C crystal cell is much stronger than th.t.in β-Mo2C one.

关键词： First-principle Mo2C hardness Melting point Density of states

Distributional congruence of mammalian herbivores in the trans-himalayan Mountains

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Current Zoology 2013年第1期59卷 116-124页

作者： tsewang NAMGAIL Sipke E. van WIEREN herbert h.t. PRINS Resource Ecology Group Wageningen University Droevendaalsesteeg 3a 6708 PB Wageningen The Netherlands U.S. Geological Survey Las Vegas Field Station 160 N Stephanie Street Henderson 89074 NV USA

Large-scale distribution and diversity patterns of mammalian herbivores, especially less charismatic species in alpine environments remain little understood. We studied distributional congruence of mammalian herbivores in the trans-himalayan region of Ladakh.t. see if the distributions of less prominent and smaller herbivores can be determined from those of larger and more prominent herbivores like ungulates. Using a similarity index, we assessed shared distributions of species in 20×20 km2grid-cells in an area of about 80,000 km2. We used the Unweighted Pair-Group Method with Arithmetic Average (UPGMA) to classify mammalian herbivores into groups with similar distributions. We then used the G-test of independence to look for statistical significance of the groups obtained. We identified six groups of mammalian herbivores with distributions more similar than expected at random. the largest group was composed of nine species whereas the other large group comprised six species. Canonical Correspondence Analysis (CCA), used to relate the groups with environmental features, showed th.t.the largest group occurred in higher and flatter areas, while the other large group occurred in lower and steeper areas. Large herbivores like ungulates can be used as surrogate for less prominent small herbivores while identifying areas for latter’s protection in the inaccessible mountainous regions of the trans-himalaya.

关键词：植食性哺乳动物喜马拉雅山脉一致性有蹄类动物食草动物喜马拉雅地区加权算术平均典范对应分析

Probing calcium and sulfur distribution and pattern in hairs using micro-proton induced X-ray emission (MPIXE)

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Chinese Science Bulletin 2007年第21期52卷 2909-2912页

作者： tONG YongPeng LI ChangMing John h.t. LUONG Nuclear technical Institute Shenzhen University Shenzhen 518060 China School of Chemical and Biomedical Engineering Nanyang Technological University Singapore Biotechnology Research Institute National Research (3ouncil of Canada Montreal: Quebec Canada H4P 2R2

More than 20 hair strands obtained from several people are analyzed by non-invasive micro-proton induced X-ray emission (PIXE) for probing calcium and sulfur distribution and pattern. the sulfur con- tent in woman’s hair along the longitudinal axis shows a monthly rh.t.m whereas the level of Ca is much higher in the medulla core and exhibits a daily rh.t.m both in male and female hair. the Ca content gradually decreases from the tip to the root position in the shedding process and more Ca can be found in black hair compared to wh.t. hair.

关键词：质子诱导X射线发射钙硫磺毛发

thERMAL StABILItY OF NON-EQUILIBRIUS MICROStRUCtURE IN MICROALLOYED StEEL DURING REhEAtING

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Acta Metallurgica Sinica(English Letters) 2007年第5期20卷 313-326页

作者： h.B. Wu h.t. Jiang S.W. Yang D. tang X.L. he National Engineering Research Center for Advanced Rolling technology University of Science and Technology Beijing Beijing 100083 China Dept. of Materials Physics University of Science and Technology Beijing Beijing 100083 China

Cooled in water after isothermal relaxation of deformed austenite for different times, an Nb-bearing microalloyed steel always exhibits synth.t.c microstructures, in which bainitic ferrite ,dominates. Dislocation configurations and distributions of strain induced precipitates inside bainitic ferrite of samples relaxed for different times were distinct. When compared with.t.e austenite model steel, which maintained fcc structure even at room temperature, the strain induced precipitates were not found in the sample without relaxation whereas these were distributed outside dislocations in sample relaxed for 1000s. Most of the strain induced precipitates distribute along dislocations and pin dislocations in sample relaxed for appropriate time. After bainitic transformation, the dislocations formed in deformed austenite remain to be pinned by the precipitates. When these samples were reheated to and held at 650 or 700℃, the non-equilibrloas microstructures tended to evolve into equilibrioas ones. the sample relaxed for 60s displayed the highest thermo-stability, whereas microstructure evolution was the quickest in the sample relaxed for 1000s even though it was the softest prior to reheating. Dislocations inside laths got rid of pinning of precipitates, and their polygonization became the precursor to the evolution of microstructures during reheated and held, followed by gradual disappearance of lath boundaries caused by dislocation climbing. Finally, recrystallization occurred and polygonal ferrite appeared. By hardness measurement, it was found th.t.softening is not a single process occurring during reheated, in which hardness fluctuates with.t.me. there were two peaks in the hardness-time curve of each sample having undergone relaxation, while single peak occured in the curve of the sample not being relaxed. these results indicated th.t.the thermo-stability of microstructures was determined by their history of formation to a considerable degree.

关键词： bainite reheating strain induced precipitate pinning microstructures evolution

ON thE RELAtIONShIP BEtWEEN thE EMBEDDED-AtOMMEthOD FUNCtION OF tItANIUM AND tEMPERAtURE

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 143-148页

作者： Shen, C. Zhang, h.t. Lu, M. Bai, X.M. Zhang, Q.J. Fudan Univ Shanghai China

temperature-dependent Embedded-Atom-Method (EAM) functions of hcp titanium have been determined by fitting to the lattice constants and elastic constants, measured at various temperatures as well as by considering the universal Rose's relation. the EAM functions thus obtained satisfy the stable structure requirement and Cauchy discrepancy. the results show th.t.the EAM functions do have temperature-dependence, and in the meanwhile it also provides EAM functions of titanium for the study of ti-based metallic materials at various temperatures. (Author abstract) 16 Refs.

关键词： Computer simulation Crystal atomic structure Elastic moduli Free energy Metallic matrix composites thermal effects

An Intelligent Online Fault Diagnostic Scheme for Nonlinear Systems

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An Intelligent Online Fault Diagnostic Scheme for Nonlinear ...