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Structural and microstructural description of relaxor-ferroelectric transition in quenched Na_(1/2)Bi_(1/2)TiO_(3)-BaTiO_(3)

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Journal of Materiomics 2022年第4期8卷 823-832页

作者： Andreas Wohninsland Ann-Katrin Fetzer Rachel Broughton Jacob l.Jones K.V.lalitha Department of Materials-and Geosciences Technical University of Darmstadt64287DarmstadtGermany Department of Materials Science and Engineering North Carolina State UniversityRaleighNC27695USA

Quenching lead-free Na_(1/2)Bi_(1/2)TiO_(3)-based ceramics from sintering temperature is established to increasethe depolarization temperature,Td and the lattice *** situ synchrotron X-ray diffractionmeasurements were carried out on furnace cooled and quenched Na_(1/2)Bi_(1/2)TiO_(3)-BaTiO_(3)(NBT-BT)with 6and 9 mol.%BT to discern the field-induced ferroelectric *** fractions were determined fromfull pattern Rietveld refinements and utilized together with the change in unit cell volume to calculatevolumetric strain resulting from phase ***-6BT demonstrates a cubic symmetry in thefurnace cooled state but quenching stabilizes the rhombohedral R3c phase and delays the formation of afield-induced,long range-ordered tetragonal phase,thereby shifting the onset of macroscopic strain tohigher fields.A field-induced phase transition from a weakly distorted rhombohedral to tetragonal phasecan be observed in furnace cooled ***,this phase transition cannot be detected inquenched NBT-9BT,since the ferroelectric tetragonal P4mm phase is stabilized in the initial *** to the furnace cooled materials,both the quenched compositions exhibit overall negligiblevolumetric strain as a function of electric ***,scanning electron micrographs of chemi-cally etched,poled and unpoled samples reveal an increased lamellar domain contrast in the *** these findings strengthen the hypothesis of a stabilized ferroelectric order resulting in theabsence of a field-induced phase transformation in quenched NBT-BT.

关键词： lead-free Quenching Na_(1/2)Bi_(1/2)TiO_(3)-BaTiO_(3) Synchrotron diffraction Ferroelectric

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Ultrastructure of multicellular dwarf males with external gametangium in Oedogonium macrandrium(Oedogoniales,Chlorophyta)

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BIOCEll 2013年第3期37卷 85-90页

作者： Silvana l.D’AMICO Patricia I.lEONARDI Eduardo J.CÁCERES laboratorio de Ficología y Micología Departamento de BiologíaBioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina CERZOS-CONICET Camino La Carrindanga Km 7Bahía BlancaArgentina

This is the first comprehensive ultrastructural study on dwarf males with external gametangia in the ge in the genus Oedogonium,from androspore germination to the liberation of mature male *** ultrastructure of the process in *** Wittrok is similar to that of Bulbochaete hiloensis(Nordstedt)Tiffany,butwith two remarkable *** ***:(1)instead of a true transverse wall,only condensed mucilage appears between the gametes of each antheridial cell,and (2)the cell wall between the basal cell and the basal most antheridial cell has simple plasmodesmata similar to those present in the transverse walls of vegetative cells,which are absent in ***.

关键词： androspores Chlorophyta dwarf males Oedogoniales Oedogonium macrandrium ultrastructure

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Chilling Tendency and Chill of Cast Iron

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Tsinghua Science and Technology 2008年第2期13卷 177-183页

作者： E. Fraé M. Górny W. Kapturkiewicz H. lópez AGH University of Science and Technology University of Wisconsin-Milwaukee

An analytical expression is presented for the susceptibility of liquid cast iron to solidify according to the Fe-C-X metastable system （also known as the chilling tendency of cast iron, CT）. The analysis incorporates the nucleation and growth processes associated with the eutectic transformation. The CT is related to the physicochemical state of the liquid, the eutectic cells in the flake graphite, and the number of nodules in nodular cast iron. In particular, the CT can be related to the critical wall thickness, Scr, or the chill width, Wcr, in wedge shaped castings. Finally, this work serves as a guide for understanding the effect of technical factors such as the melt chemistry, the spheroidizing and inoculation practice, and the holding time and temperature on the resultant CT and chill of the cast iron. Theoretical calculations of Sc, and Wc, compare well with experimental data for flake graphite and nodular cast iron.

关键词： chill chilling tendency gray cast iron nodular cast iron

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Pollen indication to source plants in the eastern desert of China

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Chinese Science Bulletin 2005年第15期50卷 1632-1641页

作者： lI Yuecong XU Qinghai ZHAO Yinclkui YANG Xiaolan XIAO Jule CHEN Hui lü Xinmiao Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029 China College of Resources and Environment Hebei Normal UniversityShijiazhuang 050016 China Department of Environmental Management University of Central Lancashire Preston UN Hebei Geography Institute Hebei Academy of Sciences Shijiazhuang 050011 China Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

In order to investigate the indication of major pollen types to source plants, 39 surface pollen samples are collected from 39 plant communities. The results show that diversity of pollen assemblages presents in different commu-nities. Chenopodiaceae pollen percentages are highest in Kalidium communities and Ceratoides communities (higher than 45%, average is 63.4%), but high Ephedra pollen per-centages (higher than 3.3%, average is 16.5%)in Ceratoides communities make it distinguished from Kalidium communi-ties. Artemisia pollen percentages (more than 50%) are much higher than Chenopodiaceae (less than 35%) in Artemisia Communities. Nitraria pollen percentages (higher than 2%, average is 13.6%) are highest in Nitraria communities com-pared with those in other community patterns. Tamariceae pollen percentages (higher than 2%, average is 8.6%) are highest both in Tetraena and Reaumuria communities com-pared with those in other community patterns. But in Reau-muria communities, Artemisia pollen percentages are higher than Chenopodiaceae with some other pollen types such as Gramineae, Compositae, leguminosae; on the contrary, in Tetraena communities, Artemisia pollen percentages are less than Chenopodiaceae with few other pollen types. Calli-gonum pollen only appears in Calligonum communities (higher than 2%,average is 5%). The results of cluster analysis (ClA) and detrended correspondence analysis (DCA) show that the pollen indication to source plants can be reflected by association indices (A), over-representation in-dices (O), under-representation indices (U), R-value, the av-erage pollen percentages where parent plants are absent (Xa) and the average pollen percentages where parent plants are present (Xp). Zygophyllum, Calligonum, Tetraena, Tribulus and Tamariceae can indicate source plants very well, owing to high A scores. Artemisia, Chenopodiaceae and Gramineae have high R-values, and Nitraria, Cruciferae and sedum have high O scores, so they are over-represente

关键词：中国沙漠地区花粉传播遗传特性繁殖方法

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Sequence assembly using next generation sequencing data —challenges and solutions

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Science China(life Sciences) 2014年第11期57卷 1140-1148页

作者： CHIN Francis Y.l. lEUNG Henry C.M. YIU S.M. Department of Computer Science The University of Hong Kong

Sequence assembling is an important step for bioinformatics *** the help of next generation sequencing(NGS)technology,high throughput DNA fragment(reads)can be randomly sampled from DNA or RNA molecular ***,as the positions of reads being sampled are unknown,assembling process is required for combining overlapped reads to reconstruct the original DNA or RNA *** with traditional Sanger sequencing methods,although the throughput of NGS reads increases,the read length is shorter and the error rate is *** introduces several problems in ***,paired-end reads instead of single-end reads can be sampled which contain more *** existing assemblers cannot fully utilize this information and fails to assemble longer *** this article,we will revisit the major problems of assembling NGS reads on genomic,transcriptomic,metagenomic and metatranscriptomic *** will also describe our IDBA package for solving these *** package has adopted several novel ideas in assembling,including using multiple k,local assembling and progressive depth *** with existence assemblers,IDBA has better performance on many simulated and real sequencing datasets.

关键词： genomic assembling de Bruijn graph paired-end reads next generation sequencing

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Prevalence of visual impairment and estimation of refractive errors among school children in Kakamega,Kenya

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International Journal of Ophthalmology(English edition) 2024年第5期17卷 932-939页

作者： Isabel Signes-Soler Alfred Ragot Sheilah Nangena Andrew Wekesa Raúl Montalbán llamusí Department of Optics and Optometry and Vision Sciences Universidat de ValènciaBurjassotValencia 46010Spain NGO Vision Without Borders(Visio Sense Fronteres VSF)Calpe 03710AlicanteSpain Masinde Muliro University of Science and Technology P.O Box 190-50100KakamegaKenya Clinica Baviera Alicante C/Ausóy Monzó 16Alicante 03006Spain

AIM:To investigate the prevalence of visual impairment(VI)and provide an estimation of uncorrected refractive errors in school-aged children,conducted by optometry students as a community ***:The study was *** 3343 participants were included in the *** initial examination involved assessing the uncorrected distance visual acuity(UDVA)and visual acuity(VA)while using a+2.00 D *** inclusion criteria for a subsequent comprehensive cycloplegic eye examination,performed by an optometrist,were as follows:a UDVAl(0.20 logMAR)and/or a VA with+2.00 D≥0.8 decimal(0.96 logMAR).RESUlTS:The sample had a mean age of 10.92±2.13y(range 4 to 17y),and 51.3%of the children were female(n=1715).The majority of the children(89.7%)fell within the age range of 8 to *** the ethnic groups,the highest representation was from the luhya group(60.6%)followed by luo(20.4%).Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17(range 1.70 to 0.22).Out of the total,246 participants(7.4%)had a full eye *** estimated prevalence of myopia(defined as spherical equivalent≤-0.5 D)was found to be 1.45%of the total *** around 0.18%of the total sample had hyperopia value exceeding+1.75 *** astigmatism(cillence was 1.26%of the total *** our cases of VI,76.2%could be attributed to uncorrected refractive *** was detected in 0.66%(22/3343)of the screened *** was no statistically significant correlation observed between age or gender and refractive ***:The primary cause of VI is determined to be uncorrected refractive errors,with myopia being the most prevalent refractive error *** findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.

关键词： visual impairment refractive errors myopia amblyopia sustainable development goals

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Time-lapse 3-D Seismic Wave Simulation via the Generalized Multiscale Finite Element Method

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Communications in Computational Physics 2020年第6期28卷 401-423页

作者： Yongchae Cho Richard l.Gibson,Jr. Hyunmin Kim Mikhail Artemyev Yalchin Efendiev Shell International Exploration&Production Inc. 150 N Dairy Ashford RoadHoustonTX 77079USA Department of Geology&Geophysics Texas A&M UniversityCollege StationTexas 77843-3115USA Shell Exploration&Production Company 701 Poydras StreetNew OrleansLA 70139USA Arista Networks DublinIreland Department of Mathematics Texas A&M UniversityCollege StationTexas 77843-3368USA Multiscale Model Reduction laboratory North-Eastern Federal UniversityYakutskRepublic of Sakha 677980Russia

Numerical solution of time-lapse seismic monitoring problems can be challenging due to the presence of finely layered *** wave modeling using fine layered meshes also adds more computational *** approaches such as finite difference and finite element methods may be prohibitively expensive if the whole domain is discretized with the cells corresponding to the grid in the reservoir subdomain.A common approach in this case is to use homogenization techniques to upscale properties of subsurface media and assign the background properties to coarser grid;however,inappropriate application of upscaling might result in a distortion of the model,which hinders accurate monitoring of the fluid change in *** this work,we instead investigate capabilities of a multiscale method that can deal with fine scale heterogeneities of the reservoir layer and more coarsely meshed rock properties in the surrounding domains in the same *** address the 3-D wave problems,we also demonstrate how the multiscale wave modeling technique can detect the changes caused by fluid movement while the hydrocarbon production activity proceeds.

关键词： Fluid simulation time lapse Generalized multiscale finite element elastic wave

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Relation of eye dominancy with color vision discrimination performance ability in normal subjects

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International Journal of Ophthalmology(English edition) 2013年第5期6卷 733-738页

作者： Belkis Koctekin Nimet ünay Gündogan Ays Gül Kocak Altintas Ayse Canan Yazici Department of Physiology Baskent University Faculty of Medicine Department of Ophthalmology Ankara Ulucanlar Education and Research Hospital Department of Bioistatistics Baskent University Faculty of Medicine

AIM:To evaluate the performance of dominant eye(DE) for color vision discrimination ability among the medical students with normal color ***:Total of 50 students studying at Baskent University Faculty of Medicine,including 31 males(62%) and 19 females(38%),with visual acuity of 20/20 and without congenital color vision deficiency(CCVD) evaluated by Ishihara pseudoisochromatic plate test(IPPT) were recruited for this prospective comparative study upon their voluntary *** was determined by the Gündogan *** color discrimination ability was examined with the FarnsworthMunsell 100 hue(FM100) *** was applied by two days interval to all subjects for the three times while two eyes(TE),right eye(RE) and left eye(lE) were seeing for detecting red-green(r/g),blue-yellow(b/y) local color spectral regions error *** error scores were evaluated for both in DE and non-dominant(NDE).P values below 0.05 were considered to be statistically ***:The students aged 21.18±2.52 years(mean±SD).Without sex difference the RE and the lE dominancy were found 22(44%) and 28(56%) respectively and FM 100 test total error scores of DE in both r/g-b/y regions were found without gender difference 24.12±14.70,34.68±18.95,*** the NDE in both,r/gb/y regions error scores without gender difference were 32.20±19.21,36.24±17.56,*** difference of total error scores between the DE and NDE was found as 58.80±29.92,68.44±*** statistical differences among the DE and the NDE in r/g local region and total error scores were found significant in both genders(P<0.05,P<0.001). CONClUSION:The color vision discrimination performance ability was found prominent for *** superiority was attributed to higher sensitivity of the r/g local color spectral *** conclude that DE has priority in r/g color spectral region,probably including inhibition of NDE.

关键词： dominant eye measurement Farnsworth-Munsell 100 hue test Gündo?an method color vision color discrimination performance ability

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Changes in ecosystem carbon stocks in a grassland ash (Fraxinus excelsior) afforestation chronosequence in Ireland

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Journal of Plant Ecology 2014年第5期7卷 429-438页

作者： michael l.Wellock Rashad Rafique Christina M.laPerle Matthias Peichl Gerard Kiely Centre for Hydrology Micrometeorology and Climate ChangeDepartment of Civil and Environmental EngineeringUniversity College CorkCorkIreland Department of Microbiology and Plant Biology University of OklahomaNormanOK 73019USA Department of Forest Ecology and Management Swedish University of Agricultural SciencesUmeåSweden

Aims Government policy in Ireland is to increase the national forest cover from the current 10%to 18%of the total land area by *** represents a major land use change that is expected to impact on the national carbon(C)*** the C stocks of ecosystem bio-mass and soils of Irish grasslands and coniferous forests have been quantified,little work has been done to assess the impact of broad-leaf afforestation on C *** In this study,we sampled a chronosequence of ash(Fraxinus excel-sior)forests aged 12,20,27,40 and 47 years on brown earth soils.A grassland site,representative of the pre-afforestation land use,was sampled as a *** Findings Our results show that there was a significant decline(Pl(0-30 cm)following afforestation from the grassland(90.2 Mg C ha^(−1))to the 27-year-old forest(66.7 Mg C ha^(−1)).Subsequently,the forest soils switched from being a C source to a C sink and began to sequester C to 71.3 Mg C ha^(−1) at the 47-year-old *** found the amount of C stored in the above-and belowground biomass increased with age of the forest stands and offset the amount of C lost from the *** amount of C stored in the above-and belowground biomass increased on average by 1.83 Mg C ha^(−1) year^(−1).The increased storage of C in the biomass led to an increase in the total ecosystem C,from 90.2 Mg C ha^(−1) at the grassland site to 162.6 Mg C ha^(−1) at the 47-year-old *** a national scale,projected rates of ash afforestation to the year 2020 may cause a loss of 290752 Mg C from the soil compared to 2525936 Mg C sequestered into the tree *** effects of harvesting and reforestation may further modify the development of ecosystem C stocks over an entire ash rotation.

关键词： ash(Fraxinus excelsior l.) chronosequence soil biomass carbon ecosystem

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A generalized synthesis load model considering network parameters and allvanadium redox flow battery

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Protection and Control of Modern Power Systems 2018年第1期3卷 324-336页

作者： l Zhou Z W Peng C R Deng X Z Qi P Q li Guangdong Power Grid Corporation Information Center GuangzhouChina College of Electrical and Information Engineering Hunan UniversityChangsha 410082China

The simulation precision of the classic load model(ClM)is affected by the increasing proportion of installed energy storage capacity in the *** paper studies the all-vanadium redox flow battery(VRB)and proposes an equivalent model based on the measurement-based load modeling method,which can simulate the maximum output of the VRB energy storage system and fit the external characteristic of the system precisely in the occurrence of large disturbance and continuous small *** equivalent model is connected to ClM to form a generalized synthesis load model(GSlM),which considers the parameters of distribution network and reactive power *** with ClM,GSlM has better structures and can describe the load characteristics of distribution network with energy storage system more *** results validate the effectiveness and good parameter stability of GSlM,and show that the higher the proportion of energy storage in the grid is the better description ability GSlM has.

关键词： All-vanadium redox flow battery Classic load model Network parameter Parameter identification Reactive compensation

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