检索结果-内蒙古大学图书馆

Sampling tissue volumes using frequency-domain photon migration

Physical Review E 2004年第5期69卷 051908-051908页

作者： Frédéric Bevilacqua Joon S. You Carole K. Hayakawa Vasan Venugopalan Laser Microbeam and Medical Program Beckman Laser Institute 1002 Health Sciences Road East Irvine California 92612 USA Department of Biomedical Engineering Univeristy of California–Irvine Irvine Calfornia 92697 USA Department of Chemical Engineering and Materials Science University of California–Irvine Irvine California 92697 USA

We demonstrate the use of Monte Carlo simulations to generate photon scattering density functions (PSDFs) that represent the tissue volume sampled by steady-state and frequency-domain photon migration. We use these results to illustrate how scaling laws can be developed to determine the mean sampling depth of the multiply scattered photons detected by photon migration methods that remain valid outside the bounds of the standard diffusion approximation, i.e., at small source-detector separations and in media where the optical absorption is significant relative to scattering. Using both the PSDF computation and the newly formulated scaling laws, we focus on a comprehensive description of the effects of source modulation frequency, optical absorption, and source-detector separation on the depth of the sampled tissue volume as well as the sensitivity of frequency-domain photon migration measurements to the presence of a localized absorption heterogeneity.

关键词： Tissue

来源：评论

学校读者我要写书评

暂无评论

The Wulff Shape of Alumina: II, Experimental Measurements of Pore Shape Evolution Rates

引用

Journal of the American ceramic Society 2004年第10期83卷 2572-2583页

作者： Mikito Kitayama Takayuki Narushima Andreas M. Glaeser Department of Materials Science and Engineering University of California Lawrence Berkeley National Laboratory Berkeley California 94720 Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge Massachusetts 02139 Member American Ceramic Society. This research was supported by the Director Office of Energy Research Office of Basic Energy Sciences Materials Sciences Division of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098. Now at Functional Materials Engineering Fukuoka Institute of Technology 3-30-1 Wajiro-Higashi Higashi-ku Fukuoka 811-0295 Japan. Now at Department of Metallurgy Tohoku University Aza Aoba Aramaki Aoba-ku Sendai 980-8579 Japan.

The rate at which a facetted tetragonal cavity of nonequilibrium shape approaches a cubic equilibrium (Wulff) shape via surface diffusion was modeled. The shape relaxation rate of a facetted “stretched cylinder” was also modeled. For the first geometry, only an approximate solution based on linearizing the mean potential difference between the source and sink facets was obtained. For the stretched cylinder, both an approximate and an exact solution can be obtained; the approximate solution underestimates the evolution rate by a factor of ∼2. To assess the applicability of the models, nonequilibrium shape pores of identical initial geometry (∼20 μm × 20 μm × 0.5 μm) were introduced into (0001), {10[Onemacr]2}, {1120}, and {100} surfaces of sapphire single crystals using microfabrication techniques, ion-beam etching, and hot pressing. The large (∼20 μm × 20 μm) faces of the pore are low-index surfaces whose nature is dictated by the wafer orientation. A series of anneals was performed at 1900°C, and the approach of the pore shape to an equilibrium shape was monitored. The kinetics of shape evolution are highly sensitive to the crystallographic orientation and stability of the low-index surface that dominates the initial pore shape. The measured variations of the pore aspect ratio were compared to those predicted by the kinetic model. The observations suggest that when the initial bounding surface is unstable, shape relaxation may be controlled by diffusion. However, surface-attachment-limited kinetics (SALK) appears to play a major role in determining the pore shape evolution rate in cases where the initial bounding surfaces have orientations that are part of the Wulff shape.

关键词： alumina pores modeling

来源：评论

学校读者我要写书评

暂无评论

Publisher’s Note: “Polymer-specific effects of bulk relaxation and stringlike correlated motion in the dynamics of a supercooled polymer melt” [J. Chem. Phys. 119, 5290 (2003)]

引用

The Journal of Chemical Physics 2004年第14期120卷 6798-6798页

作者： M. Aichele Y. Gebremichael F. W. Starr J. Baschnagel S. C. Glotzer Institut Charles Sadron 6 rue Boussingault 67083 Strasbourg France Institut für Physik Johannes Gutenberg-Universität 55099 Mainz Germany Department of Chemical Engineering University of Michigan Ann Arbor Michigan 48109 Chemical Physics Program Institute for Physical Sciences and Technology University of Maryland College Park Maryland 20742 Center for Theoretical and Computational Materials Science and Polymers Division National Institute of Standards and Technology Gaithersburg Maryland 20899 Departments of Chemical Engineering and Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109

M. Aichele, Y. Gebremichael, F. W. Starr, J. Baschnagel, S. C. Glotzer; Publisher’s Note: “Polymer-specific effects of bulk relaxation and stringlike correlated

关键词：

来源：评论

学校读者我要写书评

暂无评论

Unique angular dependence of the unusual first order transition temperature in Gd5(Si0.5Ge0.5)4

Unique angular dependence of the unusual first order transit...

引用

2003 IEEE International Magnetics Conference, Intermag 2003

作者： Han, M. Jiles, D.C. Lee, S.J. Snyder, J.E. Lograsso, T.A. Schlagel, D.L. Department of Materials Science and Engineering Iowa State University IA50011 United States Metal and Ceramic Sciences Division Ames Laboratory US Department of Energy Iowa State University IA50011 United States Department of Electrical and Computer Engineering Iowa State University IA50011 United States

In this paper, we study the field dependence of the transition temperature (Tc) leads to a transition temperature which changes as a function of angle of the magnetic field in Gd5(Si0.5Ge0.5)4. © 2003 IEEE.

ISBN: (纸本)0780376471

关键词： Magnetic anisotropy

来源：评论

学校读者我要写书评

暂无评论

High-temperature thermal transport properties of a single-grain decagonal Al74Ni10Co16 quasicrystal

引用

Physical Review B 2003年第10期68卷 104202-104202页

作者： J. A. Barrow B. A. Cook P. C. Canfield D. J. Sordelet Materials Chemistry Program Ames Laboratory Ames Iowa 50011 USA Department of Chemistry Iowa State University Ames Iowa 50011 USA Metal and Ceramic Sciences Program Ames Laboratory Ames Iowa 50011 USA Department of Materials Science and Engineering Iowa State University Ames Iowa 50011 USA Condensed Matter Physics Program Ames Laboratory Ames Iowa 50011 USA Department of Physics and Astronomy Iowa State University Ames Iowa 50011 USA

Thermal transport properties have been determined for a decagonal Al74Ni10Co16 quasicrystal in the temperature range 373–873 K. Differential scanning calorimetry and a laser flash method were employed in the determination of heat capacity and thermal diffusivity, respectively. Thermal conductivity was determined from the product of diffusivity, heat capacity, and density. A high degree of anisotropy was observed between the aperiodic and periodic axes. The anisotropic heat flow is described using the thermal ellipsoid model. The model was applied to a surface oriented 45° to the major axes and substantiated from bulk measurements obtained from a sample cut along this orientation. Within this temperature range, the thermal transport of this two-dimensional quasicrystal may be described in a manner similar to anisotropic metallic single crystals.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Magnetic correlations induced by magnetic field and temperature in Gd5Ge4

引用

Physical Review B 2002年第21期65卷 214427-214427页

作者： E. M. Levin K. A. Gschneidner, Jr. V. K. Pecharsky Metal and Ceramic Sciences Program Ames Laboratory (U.S. DOE) Ames Iowa 50011-3020 Materials Science and Engineering Department Iowa State University Ames Iowa 50011-3114

Several unexpected and intriguing magnetic phenomena have been observed in the Gd5Ge4 compound. First, below ∼130 K, Gd5Ge4 is antiferromagnetic in a zero magnetic field, but it can be transformed into the ferromagnetic state both irreversibly (below 10 K) and reversibly (above 20 K) depending on the magnitude of the applied magnetic field, the temperature, and the direction of their changes. Second, the irreversible antiferromagnetic→ferromagnetic transformation at 4.3 K is abrupt in magnetic fields exceeding 18 kOe, but it is sluggish in lower (∼17 kOe) magnetic fields. Third, both the antiferromagnetic and ferromagnetic Gd5Ge4 phases may coexist indefinitely under certain combinations of the magnetic field and temperature. It is likely that the unusual magnetic correlations in Gd5Ge4 arise due to strongly anisotropic exchange interactions as a result of variations in the chemical bonding in this naturally layered, and therefore, low-dimensional magnetic system.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Cellular and molecular features that stabilize rolling on selectins under flow

Cellular and molecular features that stabilize rolling on se...

引用

Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： R.P. McEver V. Ramachandran M. Williams A.G. Klopocki D.W. Schmidtke Department of Biochemistry & Molecular Biology Cardiovascular Biology Research Program Oklahoma Medical Research Foundation University of Oklahoma Health Sciences Center and Veterans Administration Medical Center Oklahoma OK USA 'School of Chemical Engineering and Materials Science University of Oklahama Norman OK USA School of Chemical Engineering and Materials Science University of Oklahama Norman OK USA

We analyzed rolling of neutrophils or transfected CHO cells expressing PSGL-1 on immobilized P-selectin in a flow chamber. After tethering, cells initially rolled rapidly and unstably but then progressively rolled more slowly and more regularly. Small, uniform rolling steps occurred in cells that developed multiple long adhesive tethers, as visualized by both scanning electron microscopy and differential interference contrast microscopy. Deletion of the cytoplasmic domain of PSGL-1 impaired cytoskeletal interactions and rolling stability but did not prevent extrusions of membrane tethers.

关键词： Biomembranes Scanning electron microscopy Cells (biology) Humans Biology Interference Stress Cameras Proteins Biochemistry

来源：评论

学校读者我要写书评

暂无评论

Quantum Confinement in Nanocrystalline Si Superlattices

引用

MRS Online Proceedings Library 2000年第1期592卷 359-364页

作者： G. F. Grom P. M. Fauchet L. Tsybeskov J. P. McCaffrey H. J. Labbé D. J. Lockwood Department of Mechanical Engineering Materials Science Program USA Department of Electrical and Computer Engineering University of Rochester Rochester USA Institute for Microstructural Sciences National Research Council Ottawa Canada

Photoconductance spectroscopy was used to probe the effects of quantum confinement in nanocrystalline (nc)-Si/amorphous (a)-SiO2 superlattices (SLs). A Metal-Oxide-Semiconductor (MOS)-like structure with the nc-Si SL incorporated in the oxide was fabricated to study charging/discharging processes in Si nanocrystals. The fine structure observed in photoconductance spectra at low temperatures was interpreted in terms of singularities in the carrier density of states, possibly due to energy quantization. In addition, a low-resistance sample exhibited photocurrent oscillations with a frequency of several kHz, which could be a manifestation of sequential resonant carrier tunneling in the nc-Si/a-SiO2 SL.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Contributory presentations/posters

引用

Journal of Biosciences 1999年第1期24卷 33-198页

作者： N. Manoj V. R. Srinivas A. Surolia M. Vijayan K. Suguna R. Ravishankar R. Schwarzenbacher K. Zeth Diederichs G. M. Kostner A. Gries P. Laggner R. Prassl Madhusudan Pearl Akamine Nguyen-huu Xuong Susan S. Taylor M. Bidva Sagar K. Saikrishnan S. Roy K. Purnapatre P. Handa U. Varshney B. K. Biswal N. Sukumar J. K. Mohana Rao A. Johnson Vasantha Pattabhi S. Sri Krishna Mira Sastri H. S. Savithri M. R. N. Murthy Bindu Pillai Kannan M. V. Hosur Mukesh Kumar Swati Patwardhan K. K. Kannan B. Padmanabhaa S. Sasaki-Sugio M. Nukaga T. Matsuzaki S. Karthikevan S. Sharma A. K. Sharma M. Paramasivam P. Kumar J. A. Khan S. Yadav A. Srinivasan T. P. Singh S. Gourinath Neelima Alam A. Srintvasan Vikas Chandra Punit Kaur Ch. Betzel S. Ghosh A. K. Bera S. Bhattacharya S. Chakraborty A. K. Pal B. P. Mukhopadhyay I. Dey U. Haldar Asok Baneriee Jozef Sevcik Adriana Solovicova K. Sekar M. Sundaralingam N. Genov Dong-cai Liang Tao Jiang Ji-ping Zhang Wen-rui Chang Wolfgang Jahnke Marcel Blommers S. C. Panchal R. V. Hosur Bindu Pillay Puniti Mathur S. Srivatsun Ratan Mani Joshi N. R. Jaganathan V. S. Chauhan H. S. Atreya S. C. Sahu K. V. R. Chary Girjesh Govil Elisabeth Adjadj Éric Quinjou Nadia Izadi-Pruneyre Yves Blouquit Joël Mispelter Bernadette Heyd Guilhem Lerat Philippe Milnard Michel Desmadreil Y. Lin B. D. Nageswara Rao Vidva Raghunathan Mei H. Chau Prashant Pesais Sudha Srivastava Evans Coutinho Anil Saran Leizl F. Sapico Jayson Gesme Herbert Lijima Raymond Paxton Thamarapu Srikrishnan C. R. Grace G. Nagenagowda A. M. Lynn Sudha M. Cowsik Sarata C. Sahu S. Chauhan A. Bhattacharya G. Govil Anil Kumar Maurizio Pellecchia Erik R. P. Zuiderweg Keiichi Kawano Tomoyasu Aizawa Naoki Fujitani Yoichi Hayakawa Atsushi Ohnishi Tadayasu Ohkubo Yasuhiro Kumaki Kunio Hikichi Katsutoshi Nitta V. Rani Parvathy R. M. Kini Takumi Koshiba Yoshihiro Kobashigawa Min Yao Makoto Demura Astushi Nakagawa Isao Tanaka Kunihiro Kuwajima Jens Linge Seán O. Donoghue Michael Nilges G. Chakshusmathi Girish S. Ratnaparkhi P. K. Madhu R. Varadarajan C. Tetreau Molecular Biophysics Unit Indian Institute of Science Bangalore India Austrian Academy of Sciences Institute of Biophysics and X-ray Structure Research Graz Austria Faculty of Biology University of Konstanz Germany Institute of Medical Biochemistry University of Graz Austria Howard Huges Medical Institute Department of Chemistry & Biochemistry University of California La Jolla USA Department of Chemistry & Biochemistry University of California San Diego La Jolla USA Molecular Biophysics Unit India Department of Microbiology &Cell Biology Indian Institute of Science Bangalore India Macromolecular Structure Laboratory NCI - Frederick Cancer Research and Development Center ABL - Basic Research Program Frederick USA Department of Crystallography and Biophysics University of Madras Chennai Biochemistry Department Indian Institute of Science Bangalore India Condensed Matter Physics Division B.A.R.C. Trombay Mumbai Condensed Matter Physics Division Bhabha Atomic Research Centre Trombay Mumbai IMCB The University of Tokyo Tokyo Japan Mitsubishi Chemical Corporation Yokohama Research Center Yokohama Japan Faculty of Pharmaceutical Sciences Chiba University Chiba Japan Department of Biophysics All India Institute of Medical Sciences New Delhi India Department of Biophysics All India Institute of Medical sciences New Delhi India Institüt Physiologische Chemie Hamburg Germany Biophysics Department Bose Institute Calcutta India Slovak Academy of Sciences Institute of Molecular Biology Bratislava Slovakia Indian Institute of Science Bioinformatics Centre Bangalore Departments of Chemistry and Biochemistry Biological Macromolecular Structure Center USA Bulgarian Academy of Sciences Institute of Organic Chemistry Sofia Bulgaria Chinese Academy of Sciences Institute of Biophysics Beijing China Novartis Pharma AG Preclinical Research Basel Switzerland Department of Chemical Sciences Tata Institute of Fundamental Research Mumbai India Solid State Physics Div

来源：评论

学校读者我要写书评

暂无评论

Sol-gel synthesis of rare-earth-doped lanthanum halides for highly efficient 1.3-mu m optical amplification

引用

OPTICS LETTERS 1997年第10期22卷 691-693页

作者： Ballato, O Riman, RE Snitzer, E Fiber Optic Materials Research Program Department of Ceramic Science and Engineering Rutgers The State University of New Jersey Brett and Bowser Roads Piscataway New Jersey 08855-0909

Praseodymium- and dysprosium-doped lanthanum halide powders have been synthesized by a sol-gel-reactive-atmosphere approach. Emission at 1.3 mu m from a sol-gel-derived material was observed for the first time to our knowledge. Measured lifetimes corresponded to radiative quantum efficiencies of approximately 8% for Pr3+:LaF3, 78% for Pr3+:LaCl3, and 78% for Dy3+:LaCl3. The spectroscopic properties of these hosts are shown to be comparable with those of melt-grown single-crystal analogs, verifying the ability of inexpensive and low-temperature solution-based methodologies to produce low-phonon-energy materials. (C) 1997 Optical Society of America.

关键词： Erbium doped fiber amplifiers Fluorescent materials Optical amplification Optical amplifiers Ti:sapphire lasers X ray diffraction

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：