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NEAR'S CLOSE FLYBY OF C-TYPE ASTEROID 253 MATHILDE

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紫金山天文台台刊 1998年第2期 44-50页

作者： James F.bell III the NEAR Science Team Cornell University Department of Astronomy Ithaca NY 14853-6801 USA

On June 27, 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1200km of the main belt asteroid 253 Mathilde. Previous observations of Mathilde had revealed it to be a C-type asteroid with an astonishingly-long rotation period of 17.4 days, an albedo of 3.8%, and a mean diameter of 60 km. Observations by NEAR reveal that Mathilde has a roughly triaxial shape of 66 × 48 × 46 km diameter and a mass of 1. 02 × 10 g, implying a mean density of only 1. 3g/cm3 . The surface of Mathilde was observed to be saturated with large impact craters, showing a range of visible topography in excess of 5 km. Multispectral observations did not reveal any substantial color differences across the surface, and coverage at multiple phase angles was used to derive a preliminary albedo of 3. 5 % to 5% .The low observed density, lack of color variations, and low albedo all suggest that Mathilde may be a primitive, carbon - rich object with an interior that contains substantial pore space.

关键词：小行星飞船紫金山天文台探测

Volumetric Virtual Environments

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Journal of Computer Science & Technology 2000年第1期15卷 37-46页

作者： HE Taosong(Software Production Research Department, bell LaboratoriesLucent Technologies, Naperville, IL 60566, USA)E-mail: taosong@*** Software Production Research Department Bell Laboratories Lucent Technologies Naperville USA

Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VRsystem, specifically the modeling, rendering, and manipulations of a volumetric *** such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric 'collision detection' are introduced andimproved, with the idea of demonstrating the possibilities and potential benefits ofincorporating volumetric models into VR systems.

关键词： volume visualization volume rendering virtual reality volumegraphics object simplification level of detail wavelets theory volumetric collisiondetection

Genetics of seed flavonoid content and antioxidant activity in cowpea(Vigna unguiculata L. Walp.)

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The Crop Journal 2016年第5期4卷 391-397页

作者： Maina Antoine Nassourou Yanou Nicolas Njintang Tchiagam Jean-Baptiste Noubissié Richard Marcel Nguimbou Joseph Martin bell Department of Biological Sciences Faculty of Science University of Ngaoundéré Department of Food Science and Nutrition ENSAI University of Ngaoundéré Genetics and Plant Breeding Unit Department of Plant Biology Faculty of Science University of Yaoundé I

Information about the type of gene action governing the inheritance of cowpea seed flavonoid content and antioxidant activity is prerequisite for starting an effective breeding program for developing improved varieties. For this purpose, half-diallel crosses among seven diverse parents were made. The homozygous parents and 21 F1 hybrids were evaluated at Maroua in the Sudano-Sahelian zone of Cameroon using a randomized complete block design with three replicates. Flour samples produced from decorticated seeds were used for biochemical analysis. Analysis of variance showed significant differences(P < 0.001) among genotypes for the studied traits with ranges of 363.6–453.9 mg rutin equivalent per 100 g dry weight(DW) for total flavonoids, 13.38–30.73 mg ascorbic acid equivalent per 1 g DW for ferric iron reducing activity, 70.98–266.93 mg trolox equivalent per 100 g DW for 2,2-diphenyl-1-picrylhydrazyl(DPPH) free radical scavenging activity, and 90.93–370.62 mg trolox equivalent per 100 g DW for 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) free radical scavenging activity. Both additive and non-additive gene effects were significant in the genetic control of these traits, but dominance variance was greater than additive variance. The traits were mainly controlled by overdominance model suggesting a selection in the delayed ***- and narrow-sense heritability estimates varied from 0.90 to 0.99 and from 0.12 to 0.45,respectively. The variances due to both general and specific combining ability were highly significant for all studied traits. Recessive alleles had positive effects on DPPH and ABTS scavenging activities, whereas dominant alleles had positive effects on flavonoid content and ferric iron reducing activity. These results could help cowpea breeders to improve the antioxidant potential of cowpea seeds by appropriate selection.

关键词： Cowpea Genetic improvement Diallel analysis Antioxidant properties

Monitoring vegetation dynamics in East Rennell Island World Heritage Site using multi-sensor and multi-temporal remote sensing data

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International Journal of Digital Earth 2020年第3期13卷 393-409页

作者： Mengmeng Wang Guojin He Natarajan Ishwaran Tianhua Hong Andy bell Zhaoming Zhang Guizhou Wang Meng Wang Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijingPeople’s Republic of China College of Resources and Environment University of Chinese Academy of SciencesBeijingPeople’s Republic of China The International Centre on Space Technologies for Natural and Cultural Heritage United Nations Educational Scientific and Cultural OrganizationBeijingPeople’s Republic of China LEEP Institute University of ExeterExeterDevonUK

East Rennell of Solomon Island is the first natural site under customary law to be inscribed on UNESCO’s World Heritage *** threats due to logging,mining and agriculture led to the site being declared a World Heritage in Danger in *** East Rennell World Heritage Site(ERWHS)to‘shed’its‘Danger’status the management must monitor forest cover both within and outside of *** used satellite data from multiple sources to track forest cover changes for the entire East Rennell island since 1998.95%of the island is still covered by undisturbed forests;annual average normalized difference vegetation index(NDVI)for the whole island was above 0.91 in ***,vegetation cover in the island has been slowly decreasing,at a rate of–0.0011 NDVI per year between 2000 and *** decrease less pronounced inside ERWHS compared to areas *** potential threats due to forest clearing outside ERWHS remain the forest cover change from 2000 to 2015 has been below 15%.We suggest ways in which the Government of Solomon Islands could use our data as well as unmanned air vehicles and field surveys to monitor forest cover change and ensure the future conservation of ERWHS.

关键词： East Rennell World Heritage Site(ERWHS) vegetation cover forest cover dynamic monitoring multi-sources remote sensing data

An Integrated Planning for Reuse and Wetland Strategy of Waste Water from Rural Enterpr

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Pedosphere 1995年第3期5卷 237-243页

作者： ZHOUQI－XING R.W.bell 等 ZhejiangAgriculturalUniversity Hangzhou310029China MurdochUniversity MurdochWA6150Australia

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关键词：乡镇企业废水再利用湿地工业再循环环保计划

Efficient Variable-Coefficient Finite-Volume Stokes Solvers

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Communications in Computational Physics 2014年第10期16卷 1263-1297页

作者： Mingchao Cai Andy Nonaka John B.bell Boyce E.Griffith Aleksandar Donev Courant Institute of Mathematical Sciences New York UniversityNew YorkNY 10012USA. Center for Computational Sciences and Engineering Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA. Leon H.Charney Division of Cardiology Department of MedicineNew York University School of MedicineNYUSA. Department of Mathematics University of North CarolinaChapel HillNC 27599USA

We investigate several robust preconditioners for solving the saddle-point linear systems that arise from spatial discretization of unsteady and steady variablecoefficient Stokes equations on a uniform staggered *** on the success of using the classical projection method as a preconditioner for the coupled velocitypressure system[***,***.,228(2009),pp.7565–7595],as well as established techniques for steady and unsteady Stokes flow in the finite-element literature,we construct preconditioners that employ independent generalized Helmholtz and Poisson solvers for the velocity and pressure *** demonstrate that only a single cycle of a standard geometric multigrid algorithm serves as an effective inexact solver for each of these *** to traditional wisdom,we find that the Stokes problem can be solved nearly as efficiently as the independent pressure and velocity subproblems,making the overall cost of solving the Stokes system comparable to the cost of classical projection or fractional step methods for incompressible flow,even for steady flow and in the presence of large density and viscosity *** of the five preconditioners considered here are found to be robust to GMRES restarts and to increasing problem size,making them suitable for large-scale *** work opens many possibilities for constructing novel unsplit temporal integrators for finite-volume spatial discretizations of the equations of low Mach and incompressible flow dynamics.

关键词： Stokes flow variable density variable viscosity saddle point problems projection method preconditioning GMRES.

Multidimensional synthetic chiral-tube lattices via nonlinear frequency conversion

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Light(Science & Applications) 2020年第1期9卷 803-812页

作者： Kai Wang Bryn A.bell Alexander S.Solntsev Dragomir N.Neshev Benjamin J.Eggleton Andrey A.Sukhorukov Nonlinear Physics Centre Research School of PhysicsThe Australian National UniversityCanberraACT 2601Australia Institute of Photonics and Optical Science(IPOS) School of PhysicsUniversity of SydneySydneyNSW 2006Australia Department of Physics QOLSImperial College LondonLondon SW72AZUK School of Mathematical and Physical Sciences University of Technology SydneyUltimoNSW 2007Australia Ginzton Laboratory Stanford UniversityStanfordCA 94305USA

Geometrical dimensionality plays a fundamentally important role in the topological effects arising in discrete *** direct experiments are limited by three spatial dimensions,the research topic of synthetic dimensions implemented by the frequency degree of freedom in photonics is rapidly *** manipulation of light in these artificial lattices is typically realized through electro-optic modulation;yet,their operating bandwidth imposes practical constraints on the range of interactions between different frequency *** we propose and experimentally realize all-optical synthetic dimensions involving specially tailored simultaneous short-and long-range interactions between discrete spectral lines mediated by frequency conversion in a nonlinear *** realize triangular chiral-tube lattices in three-dimensional space and explore their four-dimensional *** implement a synthetic gauge field with nonzero magnetic flux and observe the associated multidimensional dynamics of frequency combs,all within one physical spatial *** anticipate that our method will provide a new means for the fundamental study of high-dimensional physics and act as an important step towards using topological effects in optical devices operating in the time and frequency domains.

关键词： dimensions chiral nonlinear

The community structure and microbial linkage of rumen protozoa and methanogens in response to the addition of tea seed saponins in the diet of beef cattle

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Journal of Animal Science and Biotechnology 2021年第1期12卷 272-281页

作者： Cui Tan Carlos A.Ramírez-Restrepo Ali Mujtaba Shah Rui Hu Matt bell Zhisheng Wang Chris McSweeney Institute of Animal Nutrition Sichuan Agricultural UniversityChengdu 611130SichuanChina Commonwealth Scientific and Industrial Research Organisation CSIRO Agriculture and FoodAustralian Tropical Sciences and Innovation PrecinctJames Cook UniversityTownsville QLD 4811Australia Present address:CR Eco-efficient Agriculture Consultancy(CREAC) 46 Bilbao PlaceBushland Beach QLD 4818Australia Department of Livestock Production Shaheed Benazir Bhutto University of Veterinary and Animal SciencesSakrandSindh 67210Pakistan “Low Carbon Breeding Cattle and Safety Production” University Key Laboratory of Sichuan ProvinceYa’an 625014SichuanChina School of Biosciences University of NottinghamSutton BoningtonLoughborough LE125RDUK CSIRO Agriculture Queensland BioScience PrecinctSt LuciaBrisbane QLD 4067Australia.

Background: This study investigated changes in rumen protozoal and methanogenic communities, along with the correlations among microbial taxa and methane(CH_4) production of six Belmont Red Composite beef steers fed tea seed saponins(TSS). Animals were fed in three consecutive feeding periods, a high-grain basal diet for 14 d(BD period) then a period of progressive addition of TSS to the basal diet up to 30 g/d for 20 d(TSS period), followed by the basal diet for 13 d without TSS(BDP post-control period).Results: The study found that TSS supplementation decreased the amount of the protozoal genus Entodinium and increased Polyplastron and Eudiplodinium genera. During BDP period, the protozoa community of steers did not return to the protozoal profiles observed in BD period, with higher proportions of Metadinium and Eudiplodinium and lower Isotricha. The addition of TSS was found to change the structure of methanogen community at the subgenus level by decreasing the abundance of methanogens in the SGMT clade and increasing the abundance of methanogens in the RO clade. The correlation analysis indicated that the abundance of SGMT clade methanogens were positively correlated with Isotricha, and Isotricha genus and SGMT clade methanogens were positively correlated with CH_4 production. While RO clade were positively correlated with the proportion of Metadinium genus, which was negatively correlated with CH_4 ***: These results suggest that different genera of rumen protozoa ciliates appear to be selectively inhibited by TSS, and the change in methanogen community at the subgenus level may be due to the mutualistic relationships between methanogens and rumen ciliates.

关键词： Beef steers Methane Methanogen Protozoa Tea seed saponin

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胃疡及无轻绿酸

中华医学杂志 1925年第1期11卷 32-35页

作者： bell

分析胃汁。自分验法Fractional method通行以来。对于胃疡及十二指肠疡酸度变化之观念。遂与往昔不同。盖此法比一小时试验之验法。为精确。普通观念。患胃疡及十二指

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