检索结果-内蒙古大学图书馆

Collagen Content and Organization Relate to Bone Nanomechanical Properties

MRS Online Proceedings Library 2005年第1期874卷 1-6页

作者： Donnelly, Eve Williams, Rebecca M. Baker, Shefford P. van der Meulen, Marjolein C. H. Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca USA Department of Applied and Engineering Physics Cornell University Ithaca USA Department of Materials Science and Engineering Cornell University Ithaca USA Musculoskeletal Integrity Program Hospital for Special Surgery New York USA

Cancellous bone plays an important load-bearing role in the skeleton, yet relatively little is known about the microstructure-mechanical property relationships of the tissue at the sub-10 [.proportional]m level. Cancellous tissue is characterized by a layered microstructure with variable proportions of collagen and mineral. The lamellar material is substantially stiffer than the interlamellar material at the nanomechanical level. However, the microstructural origin of the observed differences in mechanical properties of these structures has not been investigated. In this study, second harmonic generation microscopy was used to examine collagen in human vertebral cancellous bone. At the same location in the tissue, nanoindentation was used to assess the indentation modulus of lamellar and interlamellar bone. The stiff lamellae corresponded to areas of highly ordered, collagen-rich material, while the compliant interlamellar regions corresponded to areas of unoriented or collagen-poor material. The lamellar bone was approximately 30% stiffer and contained approximately 50% more oriented collagen than the interlamellar bone. These observed differences in the mechanical properties and collagen content and organization of lamellar and interlamellar tissue are consistent with previous scanning electron microscopy studies showing greater mineral and collagen content and organization in lamellar bone. Given the well-known coupling between collagen and mineral in bone tissue, the mineral distribution may mirror that of the aligned collagen. However, similar measurements of local variations in mineral content are needed to confirm this hypothesis and may provide additional insights into the tissue nanomechanical behavior.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Sensing cellular function and molecular activity in vivo using fluorescence lifetime imaging microscopy (FLIM)

Sensing cellular function and molecular activity in vivo usi...

引用

Novel Optical Instrumentation for Biomedical Applications II

作者： Zhong, Wei Sud, Dhruv Wu, Mei Merrick, Karl A. Merajver, Sofia D. Beer, David G. Mycek, Mary-Ann Dept. of Biomedical Engineering University of Michigan Ann Arbor MI 48109 Department of Internal Medicine Medical School University of Michigan Ann Arbor MI 48109 Comprehensive Cancer Center University of Michigan Medical School Ann Arbor MI 48109 Department of Surgery Medical School University of Michigan Ann Arbor MI 48109 Applied Physics Program University of Michigan Ann Arbor MI 48109

In contrast to intensity-based fluorescence microscopy, fluorescence lifetime imaging microscopy (FLIM) bases image contrast on fluorophore excited-state lifetime. This technique is sensitive to the fluorophore's local environment (temperature, ion concentration, dissolved gas concentration, and molecular associations), while being independent of factors impacting fluorescence intensity (fluorophore concentration, photobleaching, scattering, and absorption). We present design features of a novel UV-visible-NIR wide-field time-domain FLIM system with optical sectioning (10 μm), high temporal discrimination (50 ps), and large temporal dynamic range (750 ps - 1 μs), and apply the system to probe cellular metabolic function and detect molecular activity in vivo. © 2005 SPIE and OSA.

关键词： Image processing

来源：评论

学校读者我要写书评

暂无评论

Comment 1 on 'Models of optical characteristics of barrel-vault skylights: Development, validation and application' by A Laouadi

引用

Lighting Research and Technology 2005年第3期37卷 263-264页

作者： Santamouris, M. Tsagkrasoulis, A. Laouadi, Aziz Department of Applied Physics University of Athens Athens Greece Indoor Environment Research Program Institute for Research in Construction National Research Council Canada 1200 Montreal Road Ottawa Ont. K1A 0R6 Canada

Drs. Santamouris, Tsagkrasoulis and Littlefair comment on Laouadi's work which is a part of a completed project to develop a user-friendly computer tool (SkyVision) to predict the optical and daylighting performance of projecting skylights. Drs. Santamouris and Tsagkrasoulis suggest the importance of comparing results from daylighting software with those from the presented methodology. Responding to this, Laouadi states that the task is simple if the skylight is treated as one component with equivalent optical properties, which are calculated by a specialized tool. Dr. Littefair claims that the skylight shape is not usually taken into account in daylighting calculations. For his part, Louadi provides evidence that the skylight shape is an important parameter in skylight design in that it may boost or reduce the amount of light and solar heat getting into the indoor space.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Exactly Sparse Delayed-State Filters

Exactly Sparse Delayed-State Filters

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： R.M. Eustice H. Singh J.J. Leonard MIT/WHOI Joint Program in Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Woods Hole MA USA Department of Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution Woods Hole MA USA Department of Ocean Engineering Massachusetts Institute of Technology Cambridge MA USA

This paper presents the novel insight that the SLAM information matrix is exactly sparse in a delayed-state framework. Such a framework is used in view-based representations of the environment which rely upon scan-matching raw sensor data. Scan-matching raw data results in virtual observations of robot motion with respect to a place its previously been. The exact sparseness of the delayed-state information matrix is in contrast to other recent feature based SLAM information algorithms like Sparse Extended Information Filters or Thin Junction Tree Filters. These methods have to make approximations in order to force the feature-based SLAM information matrix to be sparse. The benefit of the exact sparseness of the delayed-state framework is that it allows one to take advantage of the information space parameterization without having to make any approximations. Therefore, it can produce equivalent results to the “full-covariance” solution.

关键词： Delay Simultaneous localization and mapping Navigation Cameras Oceans Information filters Sparse matrices Information filtering Remotely operated vehicles Robot vision systems

来源：评论

学校读者我要写书评

暂无评论

Femtosecond laser ablation of silicon (100) with thermal oxide thin films of varying thickness

Femtosecond laser ablation of silicon (100) with thermal oxi...

引用

Conference on Lasers and Electro-Optics, CLEO 2005

作者： McDonald, Joel P. Ray, Katherine E. Mistry, Vanita R. Mourou, Gérard Yalisove, Steven M. Center for Ultrafast Optical Science Department of Electrical Engineering University of Michigan Ann Arbor MI 48109-2099 United States Applied Physics Program 2477 Randall Laboratory University of Michigan Ann Arbor MI 48109-1120 United States College of Engineering University of Michigan Ann Arbor MI 48109 United States Department of Materials Science and Engineering 2200 Hayward Street Ann Arbor MI 48109-2136 United States

Femtosecond laser ablation of Silicon (100) with thermal oxide thin films was studied in order to further understand the ablative properties of thin films and to evaluate their influence on the ablation of the substra... 详细信息

ISBN: (纸本)1557527709

关键词： Laser ablation

来源：评论

学校读者我要写书评

暂无评论

Fracture and deformation of thermal oxide films on Si (100) using a femtosecond pulsed laser

Fracture and deformation of thermal oxide films on Si (100) ...

引用

2005 Materials Research Society Spring Meeting

作者： McDonald, Joel P. Mistry, Vanita R. Ray, Katherine E. Yalisove, Steven M. Applied Physics Program University of Michigan 2477 Randall Laboratory Ann Arbor MI 48109-1120 College of Engineering University of Michigan Lurie Engineering Center 1221 Beat Avenue Ann Arbor MI 48109-2102 Department of Materials Science and Engineering University of Michigan 2200 Hayward Ave Ann Arbor MI 48109 Center for Ultrafast Optical Science University of Michigan 1006 Gerstacker Building 2200 Bonisteel Avenue Ann Arbor MI 48109

Femtosecond pulsed laser damage of Silicon (100) with thermal oxide thin films was studied in order to further understand the optical and electrical properties of thin films and to evaluate their influence on the damage of the substrate. The damage threshold as a function of film thickness (2 - 1200 nm) was measured. The damage morphology produced by single laser pulses was also investigated. Two primary morphologies were observed, one in which the oxide film is completely removed, and the other in which the film is delaminated and expanded above the surface producing a bubble feature. © 2005 Materials Research Society.

关键词： Thin films

来源：评论

学校读者我要写书评

暂无评论

Grazing-angle scattering of electromagnetic waves in gratings with varying mean parameters: grating eigenmodes

引用

Journal of Modern Optics 2005年第3期51卷 379-397页

作者： D. K. Gramotnev S. J. Goodman T. A. Nieminen Applied Optics Program School of Physical and Chemical Sciences Queensland University of Technology GPO Box 2434 Brisbane Queensland 4001 Australia Email: d.gramotnev@qut.edu.au 2: Centre for Biophotonics and Laser Science Department of Physics The University of Queensland St Lucia Queensland 4072 Australia

A highly unusual pattern of strong multiple resonances for bulk electromagnetic waves is predicted and analysed numerically in thick periodic holographic gratings in a slab with the mean permittivity that is larger than that of the surrounding media. This pattern is shown to exist in the geometry of grazing-angle scattering (GAS), that is when the scattered wave (+1 diffracted order) in the slab propagates almost parallel to the slab (grating) boundaries. The predicted resonances are demonstrated to be unrelated to resonant generation of the conventional guided modes of the slab. Their physical explanation is associated with resonant generation of a completely new type of eigenmodes in a thick slab with a periodic grating. These new slab eigenmodes are generically related to the grating; they do not exist if the grating amplitude is zero. The field structure of these eigenmodes and their dependence on structural and wave parameters is analysed. The results are extended to the case of GAS of guided modes in a slab with a periodic groove array of small corrugation amplitude and small variations in the mean thickness of the slab at the array boundaries.

关键词： LIGHT scattering ELECTROMAGNETIC waves DIFFRACTION gratings

来源：评论

学校读者我要写书评

暂无评论

Ra16.36/Rb16.36 Nanofluidic capillaries produced via femtosecond laser induced delamination of thin thermal oxide films from Si(100) substrates

Ra16.36/Rb16.36 Nanofluidic capillaries produced via femtose...

引用

2005 MRS Fall Meeting

作者： McDonald, Joel M. Mistry, Vanita R. Ray, Katherine E. Yalisove, Steven M. Applied Physics Program University of Michigan 2477 Randall Laboratory Ann Arbor MI 48109-1120 College of Engineering University of Michigan Lurie Engineering Center 1221 Beal Avenue Ann Arbor MI 48109-2102 Deparment of Materials Science and Engineering University of Michigan 2200 Hayward Ave. Ann Arbor MI 48109 Center for Ultrafast Optical Science University of Michigan 1006 Gerstacker Building 2200 Bonisteel Avenue Ann Arbor MI 48109

ISBN: (纸本)1558998551

Highly selective and repeatable delamination of thermal oxide films from Si(100) substrates has been performed using single and multiple femtosecond laser pulses forming bubbles or blisters. By overlapping the bubbles laterally, tubes or capillaries can be formed with a range of volumes suitable for nanofluidics. By scanning the sample through the laser using an automated translation stage, patterns of tubes with arbitrary complexity can be formed, while the scan velocity can easily control the volume of the tubes. The production time for capillaries in this fashion is considerably less than with other lithographic techniques, while the proximity of the tubes to the underlying silicon substrate yields the possibility for integrated devices. The optimal laser and sample translation conditions will be presented which provide the most uniform tubes. Atomic force microscopy and optical microscopy of capillaries with a range of volumes will also be presented. © 2006 Materials Research Society.

关键词： Capillary tubes

来源：评论

学校读者我要写书评

暂无评论

Stalactite Growth as a Free-Boundary Problem: A Geometric Law and Its Platonic Ideal

引用

Physical Review Letters 2005年第1期94卷 018501-018501页

作者： Martin B. Short James C. Baygents J. Warren Beck David A. Stone Rickard S. Toomey, III Raymond E. Goldstein Department of Physics University of Arizona Tucson Arizona 85721 USA Department of Chemical and Environmental Engineering University of Arizona Tucson Arizona 85721 USA Program in Applied Mathematics University of Arizona Tucson Arizona 85721 USA Accelerator Mass Spectrometry Facility University of Arizona Tucson Arizona 85721 USA Department of Soil Water and Environmental Science University of Arizona Tucson Arizona 85721 USA Kartchner Caverns State Park P.O. Box 1849 Benson Arizona 85602 USA

The chemical mechanisms underlying the growth of cave formations such as stalactites are well known, yet no theory has yet been proposed which successfully accounts for the dynamic evolution of their shapes. Here we consider the interplay of thin-film fluid dynamics, calcium carbonate chemistry, and CO2 transport in the cave to show that stalactites evolve according to a novel local geometric growth law which exhibits extreme amplification at the tip as a consequence of the locally-varying fluid layer thickness. Studies of this model show that a broad class of initial conditions is attracted to an ideal shape which is strikingly close to a statistical average of natural stalactites.

关键词： Limestone

来源：评论

学校读者我要写书评

暂无评论

Experiments on Random Packings of Ellipsoids

引用

Physical Review Letters 2005年第19期94卷 198001-198001页

作者： Weining Man Aleksandar Donev Frank H. Stillinger Matthew T. Sullivan William B. Russel David Heeger Souheil Inati Salvatore Torquato P. M. Chaikin Department of Physics and Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics and Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Department of Chemistry and Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Department of Chemical Engineering and Princeton Institute for the Science and Technology of Materials Princeton University Princeton New Jersey 08544 USA Department of Psychology and Center for Neural Science New York University New York New York 10003 USA

Recent simulations indicate that ellipsoids can pack randomly more densely than spheres and, remarkably, for axes ratios near 1.25∶1∶0.8 can approach the densest crystal packing (fcc) of spheres, with a packing fraction of 74%. We demonstrate that such dense packings are realizable. We introduce a novel way of determining packing density for a finite sample that minimizes surface effects. We have fabricated ellipsoids and show that, in a sphere, the radial packing fraction ϕ(r) can be obtained from V(h), the volume of added fluid to fill the sphere to height h. We also obtain ϕ(r) from a magnetic resonance imaging scan. The measurements of the overall density ϕavr, ϕ(r) and the core density ϕ0=0.74±0.005 agree with simulations.

关键词： .ellipsoids Princeton New Jersey

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：