检索结果-内蒙古大学图书馆

Elastic Self-Healing during Shear Accommodation in Crystalline Nanotube Ropes

Physical Review Letters 2005年第6期94卷 065502-065502页

作者： Haiyi Liang Moneesh Upmanyu Department of Modern Mechanics University of Science and Technology of China Hefei People's Republic of China Group for Simulation and Theory of Atomic-Scale Material Phenomena (stAMP) Materials Science Program Division of Engineering Colorado School of Mines Golden Colorado 80401 USA

Rigid-tube computations of simple (transverse) shear in crystalline nanotube ropes (CNTRs) reveal that shear modulus and strength increase and decrease with the tube radius, respectively. High modulus to strength ratios suggest that dislocations play a minor role during their plasticity. The computed shear moduli are in agreement with previous studies, although shape change and rolling-based shear may modify low strain and temperature behavior. The instability past the shear strength is due to shear localization via interlayer sliding, wherein stress relief results in significant elastic energy dissipation. Large-tube radius CNTRs accommodate large strains at minimal energetic cost during sliding, due to the increasingly cohesive and short range nature of the intertube potential. Fascinatingly, the crystal aids its recovery, implying that CNTRs may be promising materials for energy absorption and tribology.

关键词： .shape change PRL energetic cost shear strength shear modulus shear localization transverse shear tube radius intertube Elastic Self-Healing Shear Accommodation Crystalline Nanotube Ropes Rigid-tube CNTRs Large-tube

来源：评论

学校读者我要写书评

暂无评论

Biocompatibility of CAD/CAM ORMOCER polymer scaffold structures

引用

MRS Online Proceedings Library 2005年第1期845卷 65-70页

作者： Doraiswamy, A. Patz, T. Narayan, R. Chichkov, B. Ovsianikov, A. Houbertz, R. Modi, R. Auyeung, R. Chrisey, D. B. Bioengineering Program & School of Material Science and Engineering Georgia Institute of Technology Atlanta USA Laser Zentrum Hannover Hannover Germany Fraunhofer Institute for Silicate Research Wurzburg Germany US Naval Research Laboratory Washington DC USA

A fresh approach with a novel process and a hybrid material is explored for developing designer 3-dimensional functional tissue scaffolds. The process of two photon-induced polymerization generally used for electronic and optical materials is introduced for developing biological scaffolds. Hybrid materials containing organic-inorganic units, ORMOCERs, fabricated with this process are tested for biocompatibility using various cell-types and compared with known standards such as polystyrene and ECM (Extracellular Matrix). Results show good adherence of different cells to these materials, and a growth rate comparable to bioactive materials. Structures with various surface topologies are developed and tested for preferential growth. The study is a first step towards developing bioactive and bioresorbable heterogeneous three-dimensional scaffolds.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Matrix Assisted Pulsed Laser Evaporation of Dexamethasone Thin Films

引用

MRS Online Proceedings Library 2005年第1期845卷 82-86页

作者： Patz, Timothy M. Doraiswamy, Anand Narayan, Roger J. Menegazzo, Nicola Kranz, Christine Mizakoff, Boris Zhong, Yinghui Bellamkonda, Ravi Modi, Rohit Chrisey, Douglas B. Bioengineering Program and School of Material Science and Engineering Georgia Institute of Technology Atlanta USA Georgia Institute of Technology School of Chemistry and Biochemistry Atlanta USA Coulter Department of Biomedical Engineering Georgia Institute of Technology Atlanta USA US Naval Research Laboratory Washington DC USA

We have demonstrated deposition of dexamethasone thin films via matrix assisted pulsed laser evaporation (MAPLE). Infrared analysis revealed that dexamethasone thin films deposited by MAPLE and by drop casting had a similar absorbance spectra. AFM imaging of the MAPLE-deposited dexamethasone thin film revealed 2–10 µm punctuate ring-like structures. Deposited dexamethasone was tested for positive bioactivity by treating primary microglia cells with lipopolysacchride and measuring nitric oxide (NO) production. The successful deposition of dexamethasone thin films can be used on neural implants to prevent tissue injury and inflammatory response.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Nano-Biodevice for Genomic Drug Discovery and Genomic Medicine

Nano-Biodevice for Genomic Drug Discovery and Genomic Medici...

引用

International Conference on MEMS, NANO and Smart Systems

作者： N. Kaji Y. Baba Y. Tezuka Y. Takamura Y. Horiike T. Nishimoto H. Nakanishi Dept. of Medicinal Chemistry The University of Tokushima Tokushima Japan Dept. of Material Science and Technology The University of Tokyo Tokyo Japan Technology Research Laboratory Shimadzu Corporation Kyoto Japan The 21st Century COE Program The University of Tokushima Tokushima Japan Single-Molecule Bioanalysis Laboratory National Institute of Advanced Industrial Science and Technology (AIST) Takamatsu Japan

We have developed nano-biodevices to accelerate genomic drug discovery and post genome sequencing researches. The nanopillar chips, which has an array of nanometer-sized pillars inside a microchannel, were successfully fabricated on quartz substrate and applied for DNA separation. The nanopillar chips showed great potential to realize fast genome analysis and integration of whole lab procedures on a single chip.

关键词： Genomics Bioinformatics Drugs DNA Microchannel Chemical technology materials science and technology Pharmaceutical technology Numerical simulation Laboratories

来源：评论

学校读者我要写书评

暂无评论

Challenge - Naval force development

引用

Naval Engineers Journal 2004年第3期116卷 57-62页

作者： Hamilton, Charles S. Program Executive Officer for Ships REAR ADMIRAL HAMILTON is a native of Amityville New York. He attended Duke University graduating in May 1974 with a bachelor of science in zoology. He was commissioned in the Navy in May 1974 through the NROTC Program at Duke. Rear Adm. Hamilton's sea tours include electronics material officer and combat information center officer in USS Hawkins (DD 873) (1974 to 1976) fire control officer and missile officer in USS Coontz (DDG 40) (1976 to1978) operations officer in USS Callaghan (DDG 994) (1981 to 1984) executive officer USS Fox (CG 33) (1986 to 1988) and commanding officer USS O'Brien (DD 975) (1991 to 1993). Rear Adm. Hamilton's shore tours include anti-submarine warfare program analyst and administrative assistant to director Program Resource Appraisal Division (OP-91) Office of the Chief of Naval Operations (1984 to 1986) head Aegis Destroyer Section (OP-355F) and financial coordinator Aegis Cruiser Destroyer Branch Office of the Chief of Naval Operations (1988 to 1990) and military staff specialist for naval war-fare in the Office of the Under Secretary of Defense (Acquisition and Technology) (1994 to 1996). In May 1996 Rear Adm. Hamilton became program manager for the arsenal ship which was designed to provide massed precision fires in support of Fleet commander's warfighting requirements. After completing the first two design phases and passing significant acquisition reform lessons learned to the DD 21 Program Office Rear Adm. Hamilton closed down the Arsenal Ship Program in March 1998. From April 1998 to February 2000 Rear Adm. Hamilton served as deputy for Fleet in the Program Executive Office Theater Surface Combatants (PEO TSC-F). In this position he was responsible for Fleet Introduction and Lifetime Support of 120 surface combatants (DDG 51 CG 47 DDG 993 DD 963 FFG 7). Rear Adm. Hamilton served as program executive officer for Surface Strike (PEO (S)) from February 2000 until November 2002. As PEO (S) he managed the Zumwalt-class DD 21/DD (X) N

The challenges which stood as an obstacle to the naval force development are discussed. The main challenge in the national security environment is to be virtually available anywhere in the world at the behest of the national command. It is observed that in surface warefare coast guard has the most applicability and expansion of their surveillance area will help in engaging other vessels away from the manned platform. It is also observed that the relationship with mission modularity and the growth between the coast guard and the navy has attracted interest among the international community.

关键词： Marine engineering

来源：评论

学校读者我要写书评

暂无评论

Structure development and physical properties achieved in the drawing and/or annealing of PEN fibers

引用

Journal of Polymer science 2000年第11期38卷

作者： Gang Wu Ming Liu Xiaoning Li John A. Cuculo College of Material Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Fibrous Material Engineering Beijing Institute of Clothing Technology Beijing 100029 China Fiber & Polymer Science Program College of Textiles North Carolina State University Raleigh North Carolina 27695

As-spun poly(ethylene-2,6-naphthalate) (PEN) fibers (i.e., precursors) prepared from high molecular weight polymer were drawn and/or annealed under various conditions. Structure and property variations taking place during the treatment process were followed via wide-angle X-ray scattering (WAXS), small-angle X-ray scattering, differential scanning calorimetry (DSC), and mechanical testing. Both the WAXS and DSC measurements of the cold-drawn samples stretched from a low-speed-spun amorphous fiber indicate that strain-induced crystallization can occur at a temperature below the glass-transition temperature and that the resultant crystal is in the α-form modification. In contrast, when the same precursor was subjected to constrained annealing, its amorphous characteristics remained unchanged even though the annealing was performed at 200 °C. These results may imply that the application of stretching stress is more important than elevated temperatures in producing α-form crystallization. The crystalline structure of the hot-drawn samples depends significantly on the morphology of the precursor fibers. When the precursor was wound at a very low speed and in a predominantly amorphous state, hot drawing induced the formation of crystals that were apparently pure α-form modification. For the β-form crystallized precursors wound at higher speeds, a partial crystalline transition from the β form to the α form was observed during the hot drawing. In contrast with the mechanical properties of the as-spun fibers, those of the hot-drawn products are not improved remarkably because the draw ratio is extremely limited for most as-spun fibers in which an oriented crystalline structure has already formed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1424–1435, 2000

关键词： poly(ethylene-2,6-naphthalate) fiber drawing annealing structural change crystalline transition

来源：评论

学校读者我要写书评

暂无评论

Thermally stimulated current and electro-optic responses in photorefractive polymers

Thermally stimulated current and electro-optic responses in ...

引用

LEOS Summer Topical Meetings

作者： T. Aoyama T. Wada Ya-Dong Zhang Y. Moritsuki Y. Yonechi H. Sasabe K. Sasaki Y. Koike Frontier Research Program RIKEN Institute of Physical and Chemical Research Wako Saitama Japan Department of Material Sciences Faculty of Science and Technology Keio University Yokohama Japan CREST Core Research for Evolutional Science and Technology JST RIKEN Institute of Physical and Chemical Research Wako Saitama Japan Chitose Institute of Science and Technology Chitose Hokkaido Japan

We describe the depolarization of photorefractive polymers by means of thermally stimulated current (TSC) and electro-optic responses. The film was prepared by spin-coating from a chloroform solution onto an ITO substrate, and dried overnight at 500 C under vacuum. For TSC measurements, the poled polymer samples were heated at a constant heating rate of 3 C/min. The resulting depolarization current was measured using a Keithley 6512 electrometer. The EO response of the poled photorefractive polymer was measured by the reflection method.

关键词： Photorefractive effect Temperature Wavelength measurement Chemical technology Heating Photorefractive materials materials science and technology Optical polymers Organic materials Organic chemicals

来源：评论

学校读者我要写书评

暂无评论

Removal of volatile organic compounds horn surfactant solutions by flash vacuum stripping in a packed column

引用

GROUND WATER MONITORING AND REMEDIATION 1998年第4期18卷 157-165页

作者： Choori, UN Scamehorn, JF O'Haver, JH Harwell, JH Umesh Choori received his B. Tech. in chemical engineering at the Indian Institute of Technology at Kharagpur and his M.S. in chemical engineering at the University of Oklahoma. John Scamehorn holds the Asahi Glass Chair in Chemical Engineering and is Associate Director of the Institute for Applied Surfactant Research at the University of Oklahoma (Norman OK 73019). He received his B.S. and M.S. at the University of Nebraska and his Ph.D. at the University of Texas all in chemical engineering. Dr. Scamehorn has worked for Shell Conoco and DuPont and has been on a number of editorial boards for journals in the area of surfactants and separation science. He has edited three books and coauthored more than 120 technical papers. His research interests include surfactant properties important in consumer product formulation and surfactant-based separation processes. John O'Haver is currently an assistant professor in chemical engineering at the University of Mississippi. He received his degrees from the University of Oklahoma two in secondary education and one in chemical engineering. Dr. O'Haver taught high school for 12 years before returning for his Ph.D. His research interests are in the areas of fundamental and applied surfactant science. Jeffrey Harwell holds the Conoco/DuPont Professorship in Chemical Engineering and is Director of the School of Chemical Engineering and Materials Science at the University of Oklahoma. He received his B.A. in chemistry and M.S. in chemical engineering at Texas A&M University a M.Div. at the Western Conservative Baptist Seminary and his Ph.D. at the University of Texas in chemical engineering. Dr. Harwell is a cofounder of Surbec Environmental and is president of Surfactant Associates. He has served as a program director at NSF for one year and was the Victor K. Lamer award winner in 1984. He has edited three books and coauthored more than 80 technical papers. His research interests include surfactants in environmental remediation and in material property modification.

Volatile organic compounds (VOCs) can be removed from contaminated ground water and subsurface media by surfactant-enhanced remediation processes. For the process to be economically competitive it is necessary to recover and reuse the surfactant from this concentrated solution. The VOC can be removed from this concentrated solution by flash vacuum stripping, leaving the surfactant solution for reuse. In this study, the flash vacuum stripping of trichloroethylene (TCE) from an anionic surfactant solution in a co-current packed column was studied under rough vacuum conditions. The presence of surfactants lead to a reduction in the overall liquid phase volumetric mass transfer coefficient (MTC) of 40 to 95%, depending on flow rate and surfactant concentration at 50 degrees C and 16 kPa. At liquid loading rates of less than 13 cm(3)/cm(2)min, the MTC of TCE decreases rapidly with an increase in liquid loading rate, and at liquid loading rates above that, the MTC decreases slightly with an increase in the liquid loading rate. This trend may have been due to foaming. At surfactant concentrations above the critical micelle concentration, the effect of surfactant concentration was not significant at liquid loading rates less than 13 cm(3)/cm(2)min. However, beyond that rate, the MTC of TCE decreased drastically with an increase in surfactant concentration. The MTC of TCE increased with an increase in temperature. A large pressure drop (3 to 4 kPa/m) was observed across the packed bed due to foaming.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Applying fuzzy functions and sequential coordination to optimization of machinery arrangement and pipe routing

引用

NAVAL ENGINEERS JOURNAL 1998年第6期110卷 43-54页

作者： Wu, BC Young, GS Schmidt, W Choppella, K Dr. Bi-Chu Wu:received a PhD in Mechanical Engineering from the University of Maryland College Park in 1991. She has worked on projects involving naval architecture design optimization solid mechanics and database development. Presently a senwr engineer with Angle Incorporated Dr Wu's research interests are in design optimization and fuzzy logic applications. Dr. Gin-Shu Young: a senior engineer with Angle Incorporated holds a PhD in Mechanical Engineering from the University of Maryland College Park. As a guest researcher with National Institute of Standards and Technologies from 1990 to 1993 he worked on vision-based navigation for autonomous vehicles. His experience also includes applications of optimization fuzzy logic neural network and genetic algorithm methods to engineering system design Mr. William Schmidt:co-founded Angle Incorporated in 1990 and has served as Vice PresidentlChiefScientist during this tame. He holds a B.Sc. in Applied Science from the Naval Acadt?my and an M.Sc. in Physics from the Naval Post Graduate School. He has cner 20 years experience in technical leadership material and personnel management. He has led the application of computer aided design (CAD) and Product Model Information Exchange to the shipbuilding industry. His experience also includes leading the amlication of model based operational analysis to support the Live Fire Test Program for DDG 51 Class Destroyers. Mr. Krishna M. Choppella:is a Sofware Engineer at Eidea Laboratories Incotporated where he works on componentbased distributed enterpvise frameworks. He has been involved in creating data analysis tools for the US Nay by integrating CAD modeis databases and graphical front ends. His work in the Masters degree program in Mechanical Engineering at the University of Texas at Austin was in di0ddase.r spectroscopy of combustion products in porous-matri burners. He received his Bachelors degree in Electrical Engineering in India. He was a Research Associate at the Centre for Laser Technology and Project Engi

Ship design is often multidisciplinary involving several design elements with various types of objectives and constraints (O/C) some easily described as mathematical formulas, others better modeled as descriptive assertions. This paper describes a method based on fuzzy functions and an integrated performance index to model O/C using descriptive assertions to be used with mathematical formulas in optimization. Another issue addressed in this paper concerns the coordination of design elements when sequentially coupled, that is, when one leads the other and the performance of the follower depends greatly on the design of the leader. Based on neuro-fuzzy techniques, the method described here coordinates and optimizes sequentially coupled elements. The two methods are applied to machinery arrangement (MA) and pipe routing (PR). Preliminary models for optimization of MA and PR are described considering convenience, producibility: engine room size, interference and location as factors in the O/C set. Some test results from MA/PR applications are presented and discussed. The methods are generic and can be extended to other elements in ship design. They are mutually independent and may be used separately Two advantages of their use are an improvement in overall performance and a reduction in the need for redesign of elements.

关键词： Optimization

来源：评论

学校读者我要写书评

暂无评论

Oriented noncrystalline structure in PET fibers prepared with threadline modification process

引用

Journal of Polymer science 1996年第12期34卷

作者： Gang Wu Jiao-Dong Jiang Paul A. Tucker John A. Cuculo Department of Polymer Science Beijing University of Chemical Technology Beijing 100029 China Department of Fibrous Material Engineering Beijing Institute of Clothing Technology Beijing 100029 China Fiber & Polymer Science Program College of Textiles North Carolina State University Raleigh North Carolina 27695

The development of an oriented noncrystalline phase in a semicrystalline polymer filament has been studied via X-ray scattering. These unique PET fibers contain a relatively high noncrystalline content and also have high tenacity, high modulus, and low breaking elongation. Fiber properties were found to be very responsive to the oriented amorphous phase content. This phase was utilized for interpreting noncrystalline orientation in PET fibers produced by a new extrusion technique. Here, the oriented noncrystalline regions in a series of PET fibers varies from 6% to 63%, depending strongly on the production conditions. In particular, samples produced with a newly developed threadline modification process possess a high content of oriented noncrystalline polymer. Measurements such as dynamic and static mechanical properties have been performed on various samples, and these properties are related to the oriented noncrystalline phase. The results provide direct evidence for the existence of highly oriented noncrystalline material in these unique PET fibers spun with a threadline modification process. © 1996 John Wiley & Sons, Inc.

关键词： poly(ethylene terephthalate) controlled threadline dynamics orientation oriented noncrystalline phase fiber properties crystallinity

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：