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Growth of ZnO Thin Film by Laser MBE: Lasing of Exciton at Room Temperature

physica status solidi (b) 2001年第2期202卷

作者： Y. Segawa A. Ohtomo M. Kawasaki H. Koinuma Z. K. Tang P. Yu G. K. L. Wong Photodynamics Research Center Frontier Research Program The Institute of Physical and Chemical Research 19-1399 Koeji-Nagamachi Aoba Sendai 980 Japan Research Laboratory of Engineering Materials Tokyo Institute of Technology 4259 Nagatsuda Midori-Ku Yokohama 226 Japan Physics Department Hongkong University of Science and Technology Clear Water Bay Kowloon Hong Kong

High quality ZnO thin film was grown by Laser MBE. A pure ceramic ZnO target was ablated by the KrF laser pulses (248 nm, 10 Hz, 1 J/cm 2 ) in an ultra high vacuum to deposit ZnO film on sapphire (0001) substrate. The lateral grain size was about 50 nm for the sample with thickness of 55 nm. At room temperature, the peak of the exciton absorption and the photoluminescence have the same energy. Under high density excitation (355 nm, 35 ps, 10 Hz), an exciton–exciton collision process was observed as P 2 and P lines where 2S exciton and ionized exciton remain. From the edge of the sample, a very rapid increase of the P line was observed with the increase of the excitation power. A fine structure that comes from the cavity mode was also observed. These facts suggest that the lasing of the exciton was observed at room temperature.

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Nonequilibrium Phase Behavior during the Random Sequential Adsorption of Tethered Hard Disks

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Physical Review Letters 2000年第21期85卷 4430-4430页

作者： Jeffrey J. Gray D. Harley Klein Roger T. Bonnecaze Brian A. Korgel Department of Chemical Engineering The University of Texas at Austin Austin Texas 78712-1062 Texas Materials Institute The University of Texas at Austin Austin Texas 78712-1062 Center for Nano- and Molecular Science and Technology The University of Texas at Austin Austin Texas 78712-1062

We simulate random sequential adsorption of tethered hard disks which undergo limited Monte Carlo surface diffusion to study kinetics and nonequilibrium phase behavior. Tethers allow the disks to move within a specified distance of their original adsorption locations, placing a control on the local entropy of each disk. As the surface coverage increases, systems with sufficiently long tethers form hexatic or crystalline lattices, while short tethers frustrate organization. Lattices form with surprisingly short tether lengths—on the order of one disk diameter.

关键词： .VOLUME coverage Nonequilibrium surface diffusion Tethers Random Sequential Adsorption Hard Disks adsorption attempts tether length

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Abstracts of presentations at the 18th Conference of the Entomological Society of Israel - May 18, 2000 - ARO, The Volcani Center, Bet Dagan, Israel

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PHYTOPARASITICA 2001年第1期29卷 51-89页

作者： [Anonymous] Dept. of Cell and Animal Biology The Hebrew University of Jerusalem Jerusalem Israel Dept. of Entomology Israel Dept. of Chemistry The Volcani Center ARO Bet Dagan Integrated Pest Management Fruit Crops Experiment Station Agriculture Company in Upper Galilee Kibbutz Yiron Ministry of Agriculture and Rural Development Extension Service Qiryat Dept. of Stored Products Pheromone Research Lab. ARO The Volcani Center Bet Dagan Israel Div. of Bioresource and Bioenvironmental Sciences Graduate School Kyushu University Fukuoka Japan Mitrani Dept. for Desert Ecology Blaustein Institute for Desert Research Ben-Gurion University of the Negev Sede Boqer Campus Israel Dept. of Chemistry University of Hamburg Germany Dept. of Entomology ARO The Volcani Center Bet Dagan Dept. of Zoology Faculty of Life Science Tel-Aviv University Tel Aviv Israel Plant Protection and Inspection Services Ministry of Agriculture and Rural Development Bet Dagan Israel Carmel Mizrahi Rishon LeZiyyon Ministry of Agriculture and Rural Development Extension Service Rehovot Israel Agricultural Department Agan Chemical Manufacturers Ashdod Israel Dept. of Entomology ARO Gilat Research Station M.P. Negev Israel Entomology Laboratory Ministry of Health Jerusalem Israel Kimron Veterinary Institute Bet Dagan Israel USDA/ARS Gainesville USA Dept. of Stored Products ARO The Volcani Center Bet Dagan Israel Dept. of Plant Protection Southwest Agricultural University Chonqing China Makliteshim Chemical Works Ltd. Be’er Sheva Israel Dept. of Entomology ARO The Volcani Center Bet Dagan Israel Jerusalem Bet Dagan Israel Plant Protection Division Extension Service Ministry of Agriculture and Rural Development 1 ha ’Hamaqim District Bet Dagan Dept. of Plant Science Faculty of Life Science Tel-Aviv University Tel Aviv Israel Dept. of Plant Sciences Tel-Aviv University Tel Aviv Vitality Biotechnologies (Israel) Ltd. Carmel Industrial Park Tirat HaCarmel Israel Max-Planck-Institut Cologne

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Hydrolysis of biodegradable polymers by superoxide ions

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Journal of Polymer science 2000年第18期37卷

作者： K. H. Lee C. Y. Won C. C. Chu Ivan Gitsov Fiber Science Program Department of Textile and Apparel and Biomedical Engineering Program Cornell University Ithaca NY 14853-4401 Department of Chemistry State University of New York College of Environmental Science and Forestry Syracuse NY 13210 Cornell Center for Materials Research and Department of Chemistry and Chemical Biology Cornell University Ithaca NY 14853-1301

The objective of this study was to examine the reactivity of superoxide ion as an oxygen nucleophile towards biodegradable biomaterials having an aliphatic polyester structure, such as poly( D , L -Lactide) (PDLLA). The changes in molecular weights and thermal properties of PDLLA were studied as a function of the superoxide ion concentration, hydrolysis time, and hydrolysis temperature. The superoxide ion induced fragmentation of PDLLA yielded a mixture of various species with different chain length. A combined size exclusion chromatography (SEC) method with a chemical tagging by phenyl isocyanate revealed that the structure of the oligomer species with the lowest molecular weight formed in the superoxide ion induced degradation mixture was linear. The significant reduction in T g was consistent with the significant reduction in the molecular weight of PDLLA. The linear low molecular fragments (dimers and trimers) in the reaction mixture could act as an internal plasticizers to enhance the T g reduction by increasing the free volume of chain ends. The relationship of T g with molecular weight of PDLLA followed the general theory of Fox–Flory. The mechanism of simple hydrolysis of ester by superoxide ion proposed by Forrester et al. was modified to interpret the data obtained from the synthetic biodegradable polymers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3558–3567, 1999

关键词： superoxide ion biodegradable polymers hydrolysis polylactide degradation

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Expanded bed adsorption of human serum albumin from very densesaccharomyces cerevesiaesuspensions on fluoride‐modified zirconia

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Biotechnology and Bioengineering 2000年第3期65卷

作者： Ashim Mullick Michael C. Flickinger Biological Process Technology Institute University of Minnesota St. Paul Minnesota USA Department of Chemical Engineering and Materials Science University of Minnesota Minneapolis Minnesota USA Department of Biochemistry Molecular Biology and Biophysics University of Minnesota St. Paul Minnesota USA

The adsorption of proteins from high cell density yeast suspensions on mixed‐mode fluoride‐modified zirconia (FmZr) particles (38 to 75 μm, surface area of 29 m 2 /g and density of 2.8 g/cm 3 ) was investigated using human serum albumin (HSA) added to Saccharomyces cerevesiae as the model expression host. Because of the high density of the porous zirconia particles, HSA (4 mg/mL) can be adsorbed from a 100 g dry cell weight (DCW)/L yeast suspension in a threefold‐expanded bed of FmZr. The expanded bed adsorption of any protein from a suspension containing >50 g DCW/L cells has not been previously reported. The FmZr bed expansion characteristics were well represented by the Richardson–Zaki correlation with a particle terminal velocity of 3.1 mm/s and a bed expansion index of 5.4. Expanded bed hydrodynamics were investigated as a function of bed expansion using residence time distribution studies with sodium nitrite as the tracer. The adsorption of HSA on FmZr exhibited features of multicomponent adsorption due to the presence of dimers. The protein binding capacity at 5% breakthrough decreased from 22 mg HSA/mL settled bed void volume for 20 g DCW/L yeast to 15 mg HSA/mL settled bed void volume for 40 g DCW/L yeast and remained unchanged for the higher yeast concentrations (60 to 100 g DCW/L). However, the batch (or equilibrium) binding capacity decreased monotonically as a function of yeast concentration (20 to 100 g DCW/L) and the binding capacity at 100 g DCW/L yeast was fivefold lower compared with that at 20 g DCW/L yeast. The lower batch binding capacity at high cell concentrations resulted from the adsorption of cells at the surface of the particles restricting access of HSA to the intraparticle surface area. Batch (or equilibrium) and column HSA adsorption results indicated that the adsorption of HSA on FmZr occurred at a time scale that may be much faster than that of yeast cells. The zirconia particles were cleaned of adsorbed HSA and yeast with a total of

关键词： fluoride‐modified zirconia expanded bed adsorption human serum albumin dense yeast suspensions

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Modification of visible light emission from silicon nanocrystals as a function of size, electronic structure, and surface passivation

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materials Research Society Symposium - Proceedings 1999年 536卷 185-190页

作者： Wolkin, M.V. Jorne, J. Allan, G. Delerue, C. Materials Science Program Department of Chemical Engineering University of Rochester Rochester NY 14627 United States

The effect of surface passivation and crystallite size on the photoluminescence of porous silicon is reported. Oxygen-free porous silicon samples with medium to ultra high porosities have been prepared by using electrochemical etching followed by photoassisted stain etching. As long as the samples were hydrogen-passivated the PL could be tuned from the red (750nm) to the blue (400nm) by increasing the porosity. We show that when surface oxidation occurred, the photoluminescence was red-shifted. For sizes smaller than 2.8nm, the red shift can be as large as 1eV but for larger sizes no shift has been observed. Comparing the experimental results with theoretical calculations, we suggest that the decrease in PL energy upon exposure to oxygen is related to recombination involving an electron or an exciton trapped in Si=O double bonds. This result clarifies the recombination mechanisms in porous silicon.

关键词： Porous silicon

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In-situ characterization of surface molecular orientation of polymer films by fiber optic UV reflection dichroism

American Chemical Society, Polymer Preprints, Division of Po...

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American chemical Society, Polymer Preprints, Division of Polymer Chemistry 1999年第2期40卷 673-674页

作者： Weir, Michael D. Sung, Chong Sook Paik Sung, Nak Ho Polymer Program Institute of Materials Science University of Connecticut Storrs CT 06269-3136 United States Department of Chemical Engineering Tufts University Medford MA 02155 United States

The surface molecular orientation of polyethylene terephthalate (PET) films is measured using a bifurcated fiber-optic probe. The use of bifurcated fiber-optic probe in the measurement of UV dichroism using reflection techniques is successful when the polarizer is placed at the probe end, which minimizes the depolarization effect of birefringence due to external factors acting upon the fiber. This is seen by the close agreement of the dichroic ratio and orientation function when using either the specular reflection accessory or the bifurcated fiber optic. While the magnitude of reflection may change using different methods, then overall orientation measured stays relatively constant.

关键词： Plastic films

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Blackwater and Graywater on US navy ships: Technical challenges and solutions

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NAVAL ENGINEERS JOURNAL 1999年第3期111卷 293-306页

作者： Benson, J Caplan, I Jacobs, R John Benson:received his BS degree in Mechanical Engineering and MS degree in Environmental Engineering from the University of Maryland. He is a registered Professional Engineer in the State of Maryland. He Joined the Naval Sufrace Warfare Center Carderock Division Environmental Quality Department in 1990 as a project engineer and is now managing the non-oily wastewater (graywater and blackwater) project area. Mr. Ivan Caplan:graduated from Drexel University (Philadelphia Pennsylvania) with a BS in Metallurgical Engineering and was awarded a MS degree from the Johns Hopkins University (Baltimore Maryland) in Mechanics and Materials Science. Mr. Caplan has spent most of his career at the Carderock Division Naval Surface Warfare Center (NSWC) and is currently the Head of the Wastewater Management Branch in the Carderock Division's Environmental Quality Department. Previously Mr. Caplan managed the US Navy's Applied Research Program in Ship & Submarine Materials Technology. In addition Mr. Caplan was manager of the US Navy's Titanium Technology Program Office and during his government career held several external Program Manager positions on at the Naval Sea Systems Command and another at the Air Force Office of Scientific Research. Rachel Jacobs:received BS degrees in Chemical Engineering and Marine Biology from the University of Maryland College Park. After working for the Naval Research Laboratory in Washington DC and the Center for Marine Biotechnology in Baltimore MD she joined the staff of the Naval Surface Warfare Center's Environmental Quality Department in 1997. Since thta time Ms. Jacobs has worked in the non-oily wastewater treatment area and her principal responsibility has been to technically supervise the evaluation operation and modification graywater treatment.

In anticipation of more stringent environmental regulations, the increasing costs of waste disposal, and the need for naval combatants to operate unimpeded in littoral waters, the U.S. Navy has identified the need to develop technologies which are appropriate for the control and treatment of blackwater and graywater. This paper will describe the status of development efforts by the Carderock Division, Naval Surface Warfare Center (CDNSWC) and its supporting contractors, under sponsorship of Naval Sea Systems Command (NAVSEA) and the Office of Naval Research. The challenge was to develop treatment systems that meet Navy shipboard requirements for affordability, compactness, low manning/maintenance, high reliability and safety, and EM, noise, vibration and shock. Membrane ultrafiltration based systems, incorporating aerobic biological pre-treatment and ultraviolet light post treatment disinfection, have ken developed to meet these requirements. Both external and in-tank membrane systems will be described in terms of performance, system operation and space and weight advantages.

关键词： Naval vessels

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Exploiting glycation to stiffen and strengthen tissue equivalents for tissue engineering

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Journal of Biomedical materials Research Part B: Applied Biomaterials 1999年第1期46卷

作者： T. S. Girton T. R. Oegema R. T. Tranquillo Department of Chemical Engineering and Materials Science 151 Amundson Hall University of Minnesota 421 Washington Avenue S.E. Minneapolis Minnesota 55455 Department of Orthopaedic Surgery and Department of Biochemistry Molecular Biology and Biophysics University of Minnesota Minneapolis Minnesota 55455

Glycation, the nonenzymatic crosslinking of proteins by reducing sugars, is known to cause stiffening of soft tissues over a lifetime, particularly in diabetics. We show here that glycation due to elevated glucose and ribose concentrations in cell culture medium can be exploited in a matter of a few weeks of incubation to stiffen and strengthen tissue equivalents and to increase their resistance to collagenolytic degradation, all without loss of cell viability. Glycated tissue equivalents did not elicit inflammation or induce calcification upon subcutaneous implantation; rather, they were permissive to host integration and remodeling. Thus a pathological process might be used in a targeted way in tissue engineering to fabricate tissue equivalents with the required mechanical properties and desired resorption rate upon implantation. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 46, 87–92, 1999.

关键词： tissue equivalent tissue engineering glycation mechanical stiffening mechanical strengthening

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Contributory presentations/posters

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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

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