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OPTIMIZATION OF SHEET METAL FORMING PROCESSES USING FINITE ELEMENT SIMULATIONS

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Acta Metallurgica Sinica(English Letters) 2000年第2期13卷 531-539页

作者： K. b. Nielsen, M. R. Jensen and J. Danckert Department of Production, Aalborg University, Denmark

The paper focuses on the combination of the Finite Element simulation and optimization to improve process or product quality. Three different examples to illustrate the developed genetic approach are given. In all three examples is-DYNA3D is used to simulate the process and a general aptimiza- tion sensitivity based strategy is utilized to improve the design. The included examples are: 1) stretch bending of tubes, 2) bulging of tubes, and finally 3) hydromechanical deep drawing. these examples clearly illustrate the potential of systematic optimization in the area of metal processing.

关键词： finite element method hydroforming of tubes hydromechanical deep drawing LS-DYNA3D tube bending

Informative ISSR Markers Help Identify Genetically Distinct Accessions of Oryza rufipogon in Yield Improvement

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Rice science 2016年第5期23卷 225-241页

作者： G.HARITHA T.SUDHAKAR D.CHANDRA T.RAM b.DIVYA N.SARLA ICAR Indian Institute of Rice Research

Inter simple sequence repeat（ISSR） polymorphism was used to determine genetic diversity and phylogenetic relationships in 90 genotypes of wild and cultivated species of Oryza from different geographical regions of the world. In all the 17 primers used in ISSR-PCR, a total of 11 464 bands were amplified at 253 band positions/loci. The primer UbC-809 amplified the maximum bands（1 059） at 21 band positions. UbC-810 and UbC-835 amplified the minimum of 391 bands each at 7 and 14 band positions, respectively. The mean polymorphism information content ranged from 0.44 to 0.84 and resolving power ranged from 8.69 to 23.53. Un-weighted pair group method with arithmetic mean dendrogram and population structure based on the 17 primers separated all genotypes into 4 major clusters with a genetic similarity of 53%–100%. The first two clusters consisted of 30 O. rufipogon accessions each. In the third cluster, O. nivara and O. longistaminata grouped as one sub-cluster and all other O. nivara accessions and cultivars grouped as another sub-cluster. The fourth cluster had only five O. rufipogon accessions which can be a source of new genes. Four sub-populations were identified within O. rufipogon and two sub-populations within O. nivara at K = 7. A subset of six primers with high resolving power values were the most informative and grouped all genotypes almost similarly as the 17 primers did. Use of these six highly informative primers in ISSR-PCR is a cost effective and robust method for assessing genetic diversity in large germplasm collections of wild rice species.

关键词： Oryza wild species genetic diversity population structure inter simple sequence repeat

Combustion Derived Nanocrystalline-ZrO2 and Its Catalytic Activity for biginelli Condensation under Microwave Irradiation

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Chinese Journal of Chemistry 2011年第9期29卷 1863-1868页

作者： bhojegowd, Madhusudana Reddy M. Siddaramanna, Ashoka Siddappa, Anandakumar b. Thimmanna, Chandrappa G. Pasha, Mohamed A. Department of Studies in Chemistry Central College Campus Bangalore University Bengaluru-560001 India

Nanocrystalline zirconium（IV） oxide （nc-ZrO2） possessing high surface area was synthesized by a low tem- perature eco-friendly solution combustion method using a new organic fuel alanine. The powder XRD, SEM and surface area measurements were carried out for characterization of nc-ZrO2. The powder XRD results revealed that, the nc-ZrO2 has the pure tetragonal phase. The crystallite size calculated by Scherrer＇s formula and bET surface area were found to be ca. 53--57 nm and ca. 275 m2/g, respectively. SEM micrograph exhibited the macroporous nature of the powder, nc-ZrO2 has been employed as a catalyst for the solvent-free synthesis of 3,4-dihydro- pyrimidin-2-ones （DHPMs） by a microwave （MW） assisted one-pot, multicomponent biginelli condensation reaction of araldehydes, ethylacetoacetate and urea or thiourea. DHPMs are obtained in good to excellent yields （85%-- 96%） under this reaction condition within short interval of time （10--20 min）.

关键词： nanocrystalline-ZrO2 solution combustion araldehydes ethylaceto acetate nano materials greenchemistry catalysis 3,4-dihydropyrimidinones

The role of decomposition reactions in assessing first-principles predictions of solid stability

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npj Computational Materials 2019年第1期5卷 1120-1128页

作者： Christopher J.bartel Alan W.Weimer Stephan Lany Charles b.Musgrave Aaron M.Holder Department of Chemical and biological Engineering University of ColoradoBoulderCO 80309USA National Renewable Energy Laboratory GoldenCO 80401USA Department of Chemistry University of ColoradoBoulderCO 80309USA

The performance of density functional theory approximations for predicting materials thermodynamics is typically assessed by comparing calculated and experimentally determined enthalpies of formation from elemental phases,ΔH_(f).However,a compound competes thermodynamically with both other compounds and their constituent elemental forms,and thus,the enthalpies of the decomposition reactions to these competing phases,ΔH_(d),determine thermodynamic *** evaluated the phase diagrams for 56,791 compounds to classify decomposition reactions into three types:*** that produce elemental phases,*** that produce compounds,and *** that produce *** analysis shows that the decomposition into elemental forms is rarely the competing reaction that determines compound stability and that approximately two-thirds of decomposition reactions involve no elemental *** experimentally reported formation enthalpies for 1012 solid compounds,we assess the accuracy of the generalized gradient approximation(GGA)(PbE)and meta-GGA(SCAN)density functionals for predicting compound *** 646 decomposition reactions that are not trivially the formation reaction,PbE(mean absolute difference between theory and experiment(MAD)=70 meV/atom)and SCAN(MAD=59 meV/atom)perform similarly,and commonly employed correction schemes using fitted elemental reference energies make only a negligible improvement(~2 meV/atom).Furthermore,for 231 reactions involving only compounds(Type 2),the agreement between SCAN,PbE,and experiment is within~35 meV/atom and is thus comparable to the magnitude of experimental uncertainty.

关键词： stability stability solid

A matter of time： Temporal variation in the introduction history and population genetic structuring of an invasive lizard

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Current Zoology 2015年第3期61卷 456-464页

作者： HalmahMOULE Kirilee CHAPLIN Rebecca D. bRAY Kimberly A. MILLER Michael b. THOMSON David G. CHAPPLE School of biological Sciences Monash University Clayton Victoria 3800 Australia Department of Sciences Museum Victoria Victoria 3001 Australia School of biological Sciences University of Sydney Sydney NSW 2006 Australia Allan Wilson Centre for Molecular Ecology and Evolution School of Biological Sciences Victoria University of Wellington Wellington 6140 New Zealand

Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and fragmentation. Despite this, the temporal dynamics of invasions are poorly understood, with most studies focusing on a single time point, providing us with only a snapshot of the biology and genetics of the invader. We investigated the invasion of Lord Howe Island by the delicate skinkLampropholis delicataand assessed the introduction history and genetic structure of this species over a 5-year period. Using genetic data taken from 2007, and again in 2011/12, we examined changes in the population genetic structure (whether new haplotypes had been introduced to the island, and shifts in haplotype frequencies) of the species on the island between these two time points. No new haplotypes were introduced to the island between 2007 and 2011/12; however, significant shifts in haplotype frequencies across the island were detected. We conclude that the delicate skink is expanding its range into the southern regions of the island and that the haplotype frequencies on Lord Howe Island are still in a state of highly dynamic flux. Our study highlights the importance of considering invasions as dynamic and studying them in such a way that enable us to better manage their impacts.

关键词：种群遗传结构入侵物种时间变化蜥蜴历史自然生态系统群体遗传结构频率偏移

Properties of SN Ia progenitors from light curves and spectra

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Frontiers of physics 2013年第2期8卷 144-167页

作者： P. Hoflich P. Dragulin J. Mitchell b. Sadler T. Diamond C. Gerardy Department of Physics Florida State University Talahassee USA FL 32306 Department of Physics Astronomy Clemson University Clemson USA SC 29634

With recent advances in theory and observations, direct connections emerge between the progenitors of Type Ia Supernovae （SNe Ia） and the observed light curves and spectra. A direct link is important for our understanding of the supernovae physics, the diversity of SNe Ia and the use of SNe Ia for high-precision cosmology because the details of the explosion depends sensitively on the initial conditions and the explosion scenario（s） realized in nature. Do SNe Ia originate from SD- or DD systems, and do they lead to Mcu mass explosions or dynamical mergers？ Does the statistical distribtion of SNe Ia depend on their environment which can be expected to change with redshift？ In this contribution, we will exam from the theoretical point of view the tell-tails for this connection, their consistency with the observations, and future directions. In a first section, we present the physics of the explosion, light curves and spectral formation in a nutshell to help understanding the connection. For details of the progenitor evolution and explosion physics, we refer to reviews and the other contributions in this issue. Each of the topical sections starts with a brief general review followed by a more detailed discussion of specific results. because the youth of the field, some bias is unavoidable towards results obtained within our collaborations （and FSU）. The imprint of the metallicity, progenitor stars and properties such as the central density of the exploding WD are presented. IR spectroscopy, polarimetry and imaging of SNR remnants are discussed as a tool to test for the WD properties, magnetic fields and asymmetries. We discuss different classes of Type Ia supernovae, and their environment. Possible correlations between the spectroscopic and light curve properties of SN Ia are discussed. Finally, the overall emerging picture and future developments are discussed.

关键词： supernovae: general progenitors light curves spectra

Deep Residual Network based on Image Priors for Single Image Super Resolution in FFA Images

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Computer Modeling in Engineering & Sciences 2020年第10期125卷 125-143页

作者： G.R.Hemalakshmi D.Santhi V.R.S.Mani A.Geetha N.b.Prakash National Engineering College Kovilpatti628503India

Diabetic retinopathy,aged macular degeneration,glaucoma *** widely prevalent ocular pathologies which are irreversible at advanced *** learning based automated detection of these pathologies facilitate timely clinical interventions,preventing adverse *** screen these pathologies with fundus Fluorescein Angiography Images(FFA)which capture retinal components featuring diverse morphologies such as retinal vasculature,macula,optical disk ***,these images have low resolutions,hindering the accurate detection of ocular *** of high resolution images from these images,by super resolution approaches expedites the diagnosis of pathologies with better *** paper presents a deep learning network for Single Image Super Resolution(SISR)of fundus fluorescein angiography images,modeled on residual learning,gridded interpolation and Swish activation *** image prior for this network is constructed by gridded interpolation which provides better image fidelity compared to other *** of the performance of this network and comparative analysis with benchmark architectures,on a standard dataset shows that the proposed network is superior with respect to performance metrics and computational time.

关键词： SISR FFA residual network gridded interpolation swish function

Latest Wuchiapingian to Earliest Triassic Conodont Zones and δ13 Ccarb Isotope Excursions from Deep-Water Sections in Western Hubei Province, South China

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Journal of Earth Science 2019年第5期30卷 1059-1074页

作者： bo Yang Hanxiao Li Paul b. Wignall Haishui Jiang Zhijun Niu Qian Ye Qiong Wu Xulong Lai School of Earth Sciences China University of Geosciences Wuhan 430074 China Wuhan Center of Geological Survey Wuhan 430205 China School of Earth & Environment University of Leeds Leeds LS2 9JT UK State Laboratory of Geobiology and Environmental Geology China University of Geosciences Wuhan 430074 China Non-ferrous Metals Geological Exploration bureau of Zhejiang Province Shaoxing 312000 China State Laboratory of Paleontology and Stratigraphy Nanjing Institute of Geology and Paleontology Nanjing 210008 China

Deep-water facies sections have advantages of recording complete information across the Permian-Triassic boundary(PTb). Here we present a detailed study on the conodont biostratigraphy and carbon isotope profile ranges from the Wuchiapingian-Changhsingian boundary(WCb) to the PTb of two deep-water facies sections at Zhuqiao and Shiligou in the Middle Yangtze region, western Hubei, South China. Fifteen species and three genera are identified. Eight conodont zones are recognized which in ascending order are the Clarkina orientalis, C. wangi, C. subcarinata, C. changxingensis, C. yini, C. meishanensis, Hindeodus parvus and Isarcicella isarcica zones. The onset of deposition of the deep-water siliceous strata of Dalong Formation in western Hubei began in the Late Wuchiapingian and persisted to the Late Changhsingian. Carbon isotope negative excursions occur near both the WCb and PTb in both sections. The WCb δ13 Ccarb negative excursion is in the C. orientalis and C. wangi zones. The PTb δ13 Ccarb negative excursion began in the C. yini Zone and extended to the I. isarcica Zone. The absence of several Changhsingian zones may indicate the difficulty of extracting conodonts from siliceous strata or the presence of an intra-Changhsingian hiatus.

关键词： Dalong Formation conodonts δ13Ccarb isotope Wuchiapingian-Changhsingian boundary Permian-Triassic boundary

Assessment of agri-spillways as a soil erosion protection measure in Mediterranean sloping vineyards

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Journal of Mountain Science 2017年第6期14卷 1009-1022页

作者： Jesus RODRIGO-COMINO Stefan WIRTZ Eric C. bREVIK Jose D.RUIZ-SINOGA Johannes b.bIES Instituto de Geomorfologfa y Suelos Department of Geography University of Malaga 29071 Malaga Spain Physical Geography Trier University 542-85 Trier Germany Department of Natural Sciences 291 Campus Drive Dickinson State University Dickinson ND 58601 USA

Suitable vineyard soils enhance soil stability and biodiversity which in turn protects roots against erosion and nutrient losses. There is a lack of information related to inexpensive and suitable methods and tools to protect the soil in Mediterranean sloping vineyards(>25° of slope inclination). In the vineyards of the Montes de Málaga(southern Spain), a sustainable land management practice that controls soil erosion is actually achieved by tilling rills in the down-slope direction to canalize water and sediments. because of their design and use, we call them agri-spillways. In this research, we assessed two agri-spillways(between 10 m and 15 m length, and slopes between 25.8° and 35°) by performing runoff experiments under extreme conditions(a motor driven pump that discharged water flows up to 1.33 l s^(-1) for 12 to 15 minutes: ≈1000 l). The final results showed: i) a great capacity by these rills to canalize large amounts of water and sediments; and, ii) higher water flow speeds(between 0.16 m s-1 and 0.28 m s^(-1)) and sediment concentrationrates(up to 1538.6 g l^(-1)) than typically found in other Mediterranean areas and land uses(such as badlands, rangelands or extensive crops of olives and almonds). The speed of water flow and the sediment concentration were much higher in the shorter and steeper rill. We concluded that agri-spillways, given correct planning and maintenance, can be a potential solution as an inexpensive method to protect the soil in sloping Mediterranean vineyards.

关键词：土壤侵蚀保护措施葡萄园溢洪道农业评估地中海地区水流速度