Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2005

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 1021 - 1050 of 5573

Full-Text Articles in Physical Sciences and Mathematics

Flow Lookup And Biological Motion Perception, Nicholas Howe Sep 2005

Flow Lookup And Biological Motion Perception, Nicholas Howe

Computer Science: Faculty Publications

Optical flow in monocular video can serve as a key for recognizing and tracking the three-dimensional pose of human subjects. In comparison with prior work using silhouettes as a key for pose lookup, flow data contains richer information and in experiments can successfully track more difficult sequences. Furthermore, flow recognition is powerful enough to model human abilities in perceiving biological motion from sparse input. The experiments described herein show that a tracker using flow moment lookup can reconstruct a common biological motion (walking) from images containing only point light sources attached to the joints of the moving subject.

Go to article

Liquid Crystal On Silicon Non-Mechanical Steering Of A Laser Vibrometer System, Kevin S. Kuciapinski Sep 2005

Liquid Crystal On Silicon Non-Mechanical Steering Of A Laser Vibrometer System, Kevin S. Kuciapinski

Theses and Dissertations

This research examined the possibility of using a non-mechanical beam steering device to steer the beam of a coherent laser radar system. Non-mechanical beam steering devices offer many advantages in size, weight, power requirements, and steering speeds. Additionally, non-mechanical beam steering devices present the capabilities of splitting a single beam into multiple beams as well as beam forming and expanding. The coherent laser radar system used was a Laser Vibrometer System. The beam of the laser vibrometer was steered from 0 mrad to 3 mrad at 1 mrad increments using the liquid crystal on silicon (LCOS) device. The laser vibrometer …

Go to article

Operator State Estimation For Adaptive Aiding In Uninhabited Combat Air Vehicles, Christopher A. Russell Sep 2005

Operator State Estimation For Adaptive Aiding In Uninhabited Combat Air Vehicles, Christopher A. Russell

Theses and Dissertations

This research demonstrated the first closed-loop implementation of adaptive automation using operator functional state in an operationally relevant environment. In the Uninhabited Combat Air Vehicle (UCAV) environment, operators can become cognitively overloaded and their performance may decrease during mission critical events. This research demonstrates an unprecedented closed-loop system, one that adaptively aids UCAV operators based on their cognitive functional state A series of experiments were conducted to 1) determine the best classifiers for estimating operator functional state, 2) determine if physiological measures can be used to develop multiple cognitive models based on information processing demands and task type, 3) determine …

Go to article

Algebraic Insight Underpins The Use Of Cas For Modelling, Robyn Pierce Sep 2005

Algebraic Insight Underpins The Use Of Cas For Modelling, Robyn Pierce

The Mathematics Enthusiast

Computer Algebra Systems (CAS) performs algorithmic processes quickly and correctly. Concern is commonly expressed that students using CAS will merely be pushing buttons but this paper indicates that, while CAS may assist students, this facility impacts on only one section of the mathematical modeling process: CAS may be used to help find mathematical solutions to mathematically formulated problems. Controlling and monitoring the use of CAS to perform the necessary routine processes requires the mathematical thinking referred to as algebraic insight. This paper sets out a framework of the aspects, and elements of algebraic insight and illustrates the importance of students …

Go to article

Time-Of-Flight Emission Profiles Of The Entire Plume Using Fast Imaging During Pulsed Laser Deposition Of Yba2Cu3O7−X, Carl J. Druffner, Glen P. Perram, Rand R. Biggers Sep 2005

Time-Of-Flight Emission Profiles Of The Entire Plume Using Fast Imaging During Pulsed Laser Deposition Of Yba2Cu3O7−X, Carl J. Druffner, Glen P. Perram, Rand R. Biggers

Faculty Publications

Emission time-of-flight (TOF) profiles have been obtained using gated imagery to further the process control during the pulsed laser deposition of the high temperature superconductor, YBa2Cu3O7−x⁠. An intensified charge coupled device array was used to obtain a sequence of plume images at 10ns temporal resolution and 0.2mm spatial resolution. Plume imagery is transformed to TOF profiles and pulse-to-pulse variations removed using physically based smoothing techniques. Comparison with non-imaging sensors establishes excellent agreement, with systematic uncertainties in streaming speed and temperatures of less than 15% and 8%, respectively. The resulting streaming speeds of 0.4–1.2×10 …

Go to article

Uvsd: Software For Detection Of Color Underwater Features, Yuri Rzhanov, Anton Mamaenko, M Yoklavich Sep 2005

Uvsd: Software For Detection Of Color Underwater Features, Yuri Rzhanov, Anton Mamaenko, M Yoklavich

Center for Coastal and Ocean Mapping

Underwater Video Spot Detector (UVSD) is a software package designed to analyze underwater video for continuous spatial measurements (path traveled, distance to the bottom, roughness of the surface etc.) Laser beams of known geometry are often used in underwater imagery to estimate the distance to the bottom. This estimation is based on the manual detection of laser spots which is labor intensive and time consuming so usually only a few frames can be processed this way. This allows for spatial measurements on single frames (distance to the bottom, size of objects on the sea-bottom), but not for the whole video …

Go to article

Seafloor Characterization Through The Application Of Avo Analysis To Multibeam Sonar Data, Luciano E. Fonseca, Larry A. Mayer, Barbara J. Kraft Sep 2005

Seafloor Characterization Through The Application Of Avo Analysis To Multibeam Sonar Data, Luciano E. Fonseca, Larry A. Mayer, Barbara J. Kraft

Center for Coastal and Ocean Mapping

In the seismic reflection method, it is well known that seismic amplitude varies with the offset between the seismic source and detector and that this variation is a key to the direct determination of lithology and pore fluid content of subsurface strata. Based on this fundamental property, amplitude-versus-offset (AVO) analysis has been used successfully in the oil industry for the exploration and characterization of subsurface reservoirs. Multibeam sonars acquire acoustic backscatter over a wide range of incidence angles and the variation of the backscatter with the angle of incidence is an intrinsic property of the seafloor. Building on this analogy, …

Go to article

Measurement Of In Situ Acoustic Properties For The Onr Geoclutter Program, Annual Report, Geoclutter Program, Larry A. Mayer, Barbara J. Kraft, Luciano E. Fonseca Sep 2005

Measurement Of In Situ Acoustic Properties For The Onr Geoclutter Program, Annual Report, Geoclutter Program, Larry A. Mayer, Barbara J. Kraft, Luciano E. Fonseca

Center for Coastal and Ocean Mapping

No abstract provided.

Go to article

Signature Of Chaos In High-Lying Doubly Excited States Of The Helium Atom, Anh-Thu Le, Toru Morishita, X.-M. Tong, C. D. Lin Sep 2005

Signature Of Chaos In High-Lying Doubly Excited States Of The Helium Atom, Anh-Thu Le, Toru Morishita, X.-M. Tong, C. D. Lin

Physics Faculty Research & Creative Works

We examined nearest-neighbor spacing (NNS) statistics in doubly excited states of helium near the double ionization threshold. Using the Brody parameter q to measure the NNS distribution between the regular Poisson distribution (q=0) and the chaotic Wigner distribution (q=1), we showed that for levels near the N=20 threshold of He⁺, or at about 0.13eV below the double ionization threshold, the NNS distribution has q=0.66. The result shows the slow approach of the NNS of helium energy levels towards the Wigner distribution vs the excitation energy. Using an s-wave model where the angular momentum of each electron is restricted to zero, …

Go to article

Exchange Distortion And Postcollision Interaction For Intermediate-Energy Electron-Impact Ionization Of Argon, A. Prideaux, Don H. Madison, K. Bartschat Sep 2005

Exchange Distortion And Postcollision Interaction For Intermediate-Energy Electron-Impact Ionization Of Argon, A. Prideaux, Don H. Madison, K. Bartschat

Physics Faculty Research & Creative Works

Measurements of fully differential cross sections for electron impact ionization of atoms have been performed for over 30 years. However, only within the last ten years has agreement between experiment and theory been achieved for ionization of hydrogen and helium. For the heavier inert gases, reasonably good agreement between experiment and theory has only been achieved for high incident energies while serious discrepancies are common for intermediate and low incident energies. It is believed that a major source of the problem stems from an improper/inadequate treatment of exchange distortion (ED) and the effects of post-collision interactions (PCIs). In this paper, …

Go to article

Kinetic, Spectroscopic, And X-Ray Crystallographic Characterization Of The Functional E151h Aminopeptidase From Aeromonas Proteolytica, Krzysztof P. Bzymek, Aaron Moulin, Sabina I. Swierczek, Dagmar Ringe, Gregory A. Petsko, Brian Bennett, Richard C. Holz Sep 2005

Kinetic, Spectroscopic, And X-Ray Crystallographic Characterization Of The Functional E151h Aminopeptidase From Aeromonas Proteolytica, Krzysztof P. Bzymek, Aaron Moulin, Sabina I. Swierczek, Dagmar Ringe, Gregory A. Petsko, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

Glutamate151 (E151) has been shown to be catalytically essential for the aminopeptidase from Vibrio proteolyticus (AAP). E151 acts as the general acid/base during the catalytic mechanism of peptide hydrolysis. However, a glutamate residue is not the only residue capable of functioning as a general acid/base during catalysis for dinuclear metallohydrolases. Recent crystallographic characterization of the d-aminopeptidase from Bacillus subtilis (DppA) revealed a histidine residue that resides in an identical position to E151 in AAP. Because the active-site ligands for DppA and AAP are identical, AAP has been used as a model enzyme to understand the mechanistic role of H115 in …

Go to article

Measurement Of Inelastic J/Ψ Production In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini Sep 2005

Measurement Of Inelastic J/Ψ Production In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, N. Pavel, A. G. Yagües Molina, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, A. Montanari, R. Nania, F. Palmonari, A. Pesci, A. Polini

Faculty Publications

The inelastic production of J/ψ mesons in ep collisions has been studied with the ZEUS detector at HERA using an integrated luminosity of 109 pb-1. The J/ψ mesons were identified using the decay channel J/ψ → μ+μ- The measurements were performed in the kinematic range 2 < Q2 < 80 GeV2, 50 < W < 250 GeV, 0.2 < z < 0.9 and -1.6 < Ylab < 1.3, where Q2 is the virtuality of the exchanged photon, W is the photon-proton centre-of-mass energy, z is the fraction of the photon energy carried by the J/ψ meson in the proton rest frame and Ylab is the rapidity of the J/ψ in the laboratory frame. The measured cross sections are compared to theoretical predictions within the non-relativistic QCD framework including colour-singlet and colour-octet contributions, as well as to predictions based on the κT-factorisation approach. Calculations of the colour-singlet process generally agree with the data, whereas inclusion of colour-octet terms spoils this agreement. © Springer-Verlag/Società Italiana di Fisica 2005.

Go to article

Early Warning And Prediction Of Internet Attacks And Exploits, Brian P. Zeitz Sep 2005

Early Warning And Prediction Of Internet Attacks And Exploits, Brian P. Zeitz

Theses and Dissertations

A safe, secure, and functional information network is vital in today’s Air Force net centric environment. Information is more critical today than it has ever been. As more operational functions are placed in cyber space and greater computing power becomes available to everyone, keeping these networks safe and secure is an almost unattainable task. Network security entails Intrusion Detection Security, but another form of security or “insecurity” is quickly gaining attention. Honeypots allow the black hat community to attack and penetrate non-production systems. By monitoring and studying these attacks, network defenders can develop better Information Assurance tactics, techniques and procedures …

Go to article

Interaction Of Carbon Nanotubes With Sugar Complexes, Alan Casey, Gordon Farrell, Mary Mcnamara, Hugh Byrne, Gordon Chambers Sep 2005

Interaction Of Carbon Nanotubes With Sugar Complexes, Alan Casey, Gordon Farrell, Mary Mcnamara, Hugh Byrne, Gordon Chambers

Articles

The interaction of carbon nanotubes with soft organic molecules such as cyclodextrins and other saccarides has recently been shown to produce water soluble composites. Such systems offer considerable advantages over polymer based composites due to their biocompatibility and noncovalent coupling which can potentially preserve the unique properties of the tubes. The mechanism of interaction for such systems has been proposed to be dominated by hydrophobic and hydrophilic interactions along the surface of the tube. However efforts to characterise and rationalise such noncovalent interactions between the sugar-based materials and the carbon nanotubes have been slow to emerge. In this study a …

Go to article

The Octarepeat Domain Of The Prion Protein Binds Cu(Ii) With Three Distinct Coordination Modes At Ph 7.4, Madhuri Chattopadhyay, Eric D. Walter, Dustin J. Newell, Pilgrim J. Jackson, Eliah Aronoff-Spencer, Jack Peisach, Gary J. Gerfen, Brian Bennett, William E. Antholine, Glenn L. Millhauser Sep 2005

The Octarepeat Domain Of The Prion Protein Binds Cu(Ii) With Three Distinct Coordination Modes At Ph 7.4, Madhuri Chattopadhyay, Eric D. Walter, Dustin J. Newell, Pilgrim J. Jackson, Eliah Aronoff-Spencer, Jack Peisach, Gary J. Gerfen, Brian Bennett, William E. Antholine, Glenn L. Millhauser

Physics Faculty Research and Publications

The prion protein (PrP) binds Cu2+ in its N-terminal octarepeat domain. This unusual domain is comprised of four or more tandem repeats of the fundamental sequence PHGGGWGQ. Previous work from our laboratories demonstrates that at full copper occupancy, each HGGGW segment binds a single Cu2+. However, several recent studies suggest that low copper occupancy favors different coordination modes, possibly involving imidazoles from histidines in adjacent octapeptide segments. This is investigated here using a combination of X-band EPR, S-band EPR, and ESEEM, along with a library of modified peptides designed to favor different coordination interactions. At pH 7.4, …

Go to article

Channel Electron Multiplier And Channelplate Efficiencies For Detecting Positive Ions, M. Krems, J. Zirbel, Mark Allan Thomason, Robert D. Dubois Sep 2005

Channel Electron Multiplier And Channelplate Efficiencies For Detecting Positive Ions, M. Krems, J. Zirbel, Mark Allan Thomason, Robert D. Dubois

Physics Faculty Research & Creative Works

Absolute detection efficiencies for singly and multiply charged positive ions have been measured for a channelplate and for two different channel electron multipliers (CEM). The efficiencies were measured for impact energies between approximately 0.25 and 25 keV and for ion masses ranging from 14 to 132. The maximum efficiencies were found to be the same for all ions investigated and were approximately 58% for a channelplate and 89% for the CEMs. For a channelplate it is shown that the detection efficiencies for heavier ions scale to a single curve if plotted versus the impact energy divided by the square root …

Go to article

Book Review: Observing Variable Stars, Novae, And Supernovae, T. D. Oswalt Sep 2005

Book Review: Observing Variable Stars, Novae, And Supernovae, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Observing Variable Stars, Novae, and Supernovae by Gerald North with Nick James Cambridge, 2004 230p, 0521820472 $45.00.

Go to article

Toy Blocks And Rotational Physics, Gabriele U. Varieschi, Isabel R. Jully Sep 2005

Toy Blocks And Rotational Physics, Gabriele U. Varieschi, Isabel R. Jully

Physics Faculty Works

Have you ever observed a child playing with toy blocks? A favorite game is to build towers and then make them topple like falling trees. To the eye of a trained physicist this should immediately look like an example of the physics of “falling chimneys,” when tall structures bend and break in mid-air while falling to the ground. The game played with toy blocks can actually reproduce well what is usually seen in photographs of falling towers, such as the one that appeared on the cover of the September 1976 issue of The Physics Teacher.1 In this paper we describe …

Go to article

Tme Volume 2, Number 2 Sep 2005

Tme Volume 2, Number 2

The Mathematics Enthusiast

No abstract provided.

Go to article

Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu Sep 2005

Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu

Research Collection School Of Computing and Information Systems

The Open Constraint Optimization Problem (OCOP) refers to the COP where constraints and variable domains can change over time and agents' opinions have to be sought over a distributed network to form a solution. The openness of the problem has caused conventional approaches to COP such as branch-and-bound to fail to find optimal solutions. OCOP is a new problem and the approach to find an optimal solution (minimum total cost) introduced in [1] is based on an unrealistic assumption that agents are willing to report their options in nondecreasing order of cost. In this paper, we study a generalized OCOP …

Go to article

Active-Passive Array Surface Wave Inversion And Comparison To Borehole Logs In Southeast Missouri, Alexei A. Malovichko, Neil Lennart Anderson, Dmitriy A. Malovichko, Denis Yu Shylakov, Pavel G. Butirin Sep 2005

Active-Passive Array Surface Wave Inversion And Comparison To Borehole Logs In Southeast Missouri, Alexei A. Malovichko, Neil Lennart Anderson, Dmitriy A. Malovichko, Denis Yu Shylakov, Pavel G. Butirin

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

In May 2002, both active- and passive-source surface wave data were acquired using 4-channel arrays at six selected bridge sites in southeast Missouri. Processing of acquired data (increase of signal-to-noise ratio, estimation of phase velocities) was carried out and dispersion curves of Rayleigh wave phase velocities were constructed. Each fundamental mode dispersion curve was then inverted by linearised optimization to a layered shear-wave velocity profile to depths of up to 60 m. The estimated shear-wave velocity profiles were compared to other geotechnical data that had been previously acquired at each test site for the Missouri Department of Transportation (MoDOT) including …

Go to article

Security Analysis And Improvement Of Return Routability Protocol, Ying Qiu, Jianying Zhou, Robert H. Deng Sep 2005

Security Analysis And Improvement Of Return Routability Protocol, Ying Qiu, Jianying Zhou, Robert H. Deng

Research Collection School Of Computing and Information Systems

Mobile communication plays a more and more important role in computer networks. How to authenticate a new connecting address belonging to a said mobile node is one of the key issues in mobile networks. This paper analyzes the Return Routability (RR) protocol and proposes an improved security solution for the RR protocol without changing its architecture. With the improvement, three types of redirect attacks can be prevented.

Go to article

Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo Sep 2005

Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo

Research Collection School Of Computing and Information Systems

In a rapidly changing environment, the behavior and decision-making power of agents may have to be adaptive with respect to a fluctuating autonomy. In this paper, a centralized fuzzy approach is proposed to sense changes in environmental conditions and translate them to changes in agent autonomy. A distributed coalition formation scheme is then applied to allow agents in the new autonomy to renegotiate to establish schedule consistency. The proposed framework is applied to a real-time logistics control of a military hazardous material storage facility under peace-to-war transition.

Go to article

Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay Sep 2005

Forms Of Expression For Designing Visual Languages For Animation, Richard C. Davis, James A. Landay

Research Collection School Of Computing and Information Systems

We present further steps in our research into visual languages for animation. Animation is a rich mode of communication that is currently accessible to few, because animation systems are complex. Some systems try to make animation simple but put severe limits on users’ creative expression. Our field studies are demonstrating that would-be animators need to express animation in a wide variety of ways. We are developing a taxonomy of forms of expression for animation that will help the designers of visual languages for animation to determine which expressive forms to support. Our end goal is to build animation sketching systems …

Go to article

Cuhk At Imageclef 2005: Cross-Language And Cross-Media Image Retrieval, Steven C. H. Hoi, J. Zhu, M. Lyu Sep 2005

Cuhk At Imageclef 2005: Cross-Language And Cross-Media Image Retrieval, Steven C. H. Hoi, J. Zhu, M. Lyu

Research Collection School Of Computing and Information Systems

In this paper, we describe our studies of cross-language and cross-media image retrieval at the ImageCLEF 2005. This is the first participation of our CUHK (The Chinese University of Hong Kong) group at ImageCLEF. The task in which we participated is the “bilingual ad hoc retrieval” task. There are three major focuses and contributions in our participation. The first is the empirical evaluation of language models and smoothing strategies for cross-language image retrieval. The second is the evaluation of cross-media image retrieval, i.e., combining text and visual contents for image retrieval. The last is the evaluation of bilingual image retrieval …

Go to article

Managing Geography Learning Objects Using Personalized Project Spaces In G-Portal, Dion Hoe-Lian Goh, Aixin Sun, Wenbo Zong, Dan Wu, Ee Peng Lim, Yin-Leng Theng, John Hedberg, Chew-Hung Chang Sep 2005

Managing Geography Learning Objects Using Personalized Project Spaces In G-Portal, Dion Hoe-Lian Goh, Aixin Sun, Wenbo Zong, Dan Wu, Ee Peng Lim, Yin-Leng Theng, John Hedberg, Chew-Hung Chang

Research Collection School Of Computing and Information Systems

The personalized project space is an important feature in G-Portal that supports individual and group learning activities. Within such a space, its owner can create, delete, and organize metadata referencing learning objects on the Web. Browsing and querying are among the functions provided to access the metadata. In addition, new schemas can be added to accommodate metadata of diverse attribute sets. Users can also easily share metadata across different projects using a “copy-and-paste” approach. Finally, a viewer to support offline viewing of personalized project content is also provided.

Go to article

On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng Sep 2005

On Organizing And Accessing Geospatial And Georeferenced Web Resources Using The G-Portal System, Zehua Liu, Ee Peng Lim, Yin-Leng Theng, Dion Hoe-Lian Goh, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

In order to organise and manage geospatial and georeferenced information on the Web making them convenient for searching and browsing, a digital portal known as G-Portal has been designed and implemented. Compared to other digital libraries, G-Portal is unique for several of its features. It maintains metadata resources in XML with flexible resource schemas. Logical groupings of metadata resources as projects and layers are possible to allow the entire metadata collection to be partitioned differently for users with different information needs. These metadata resources can be displayed in both the classification-based and map-based interfaces provided by G-Portal. G-Portal further incorporates …

Go to article

A Mechanism For The Formation Of Nanostructured Nizn Ferrites Via A Microemulsion-Assisted Precipitation Method, Vuk Uskoković, Miha Drofenik Sep 2005

A Mechanism For The Formation Of Nanostructured Nizn Ferrites Via A Microemulsion-Assisted Precipitation Method, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured NiZn ferrites were synthesized using two different techniques: first, a precipitation procedure in the reverse micelles of a CTAB/1-hexanol/H2O microemulsion, and second, precipitation in a bulk aqueous solution. XRD measurements, magnetic measurements, TEM imaging, analytical measurements and thermal analyses were used in an attempt to reveal the chemical pathway that leads to the formation of NiZn ferrite in the microemulsion and in the bulk aqueous solution. It was found that reverse micelles do not act as inert nano-sized reactors that influence only morphological properties of the synthesized powders, but have a decisive influence on the identity of …

Go to article

Synthesis Of Lanthanum-Strontium Magnanites By A Hydroxide-Precursor Co-Precipitation Method In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Darko Makovec, Miha Drofenik Sep 2005

Synthesis Of Lanthanum-Strontium Magnanites By A Hydroxide-Precursor Co-Precipitation Method In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Darko Makovec, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured lanthanum-strontium manganites have been synthesized using two different co-precipitation approaches, one in bulk solution, and the other in reverse micelles of CTAB/1-hexanol/1-butanol/water microemulsion. In both cases, precursor cations were precipitated by alkali precipitating agents. The properties of the material synthesized by using these two methods were compared in order to reveal potential advantages of microemulsion-assisted approach. The influence of the annealing conditions on the properties of synthesized manganites was investigated by using X-ray diffraction, transmission electron microscopy, differential thermal analysis, thermogravimetric analysis and magnetic measurements.

Go to article

Α-Enhanced Integrated Lick/Ids Spectral Indices And Milky Way And M31 Globular Clusters And Early-Type Galaxies, Hyun Chul Lee, Guy Worthey Sep 2005

Α-Enhanced Integrated Lick/Ids Spectral Indices And Milky Way And M31 Globular Clusters And Early-Type Galaxies, Hyun Chul Lee, Guy Worthey

Physics and Astronomy Faculty Publications and Presentations

All 25 Lick/IDS spectral indices have been computed for the integrated light of simple stellar populations over broad ranges of age and metallicity and with effects from horizontal-branch stars fully implemented. Our models employ α-enhanced isochrones at the sub-solar metallicity regime, but solar-scaled ones at solar and super-solar metallicity. We have also employed the updated response functions of Houdashelt et al. at the solar and super-solar metallicity regime, so that we could assess the light-element enhancement phenomena seen from metal-rich early-type galaxies. For Balmer indices a significant response was noted for Hγ and Hδ when α-elements are enhanced, but Hβ …

Go to article

First Prev Next Last