bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visible-Light Inactivation of Escherichia Coli on N-Doped Titanium Oxide Thin Films
Authors: Wu Pinggui , Shang JianKu 
Published: April 2011

AbstractAntimicrobial behavior of nitrogen-doped titanium dioxide (TiON) thin films was examined by cell viability assays under visible light illumination, using Escherichia coli as the indicator. The nitrogen doping was found to enable visible-light inactivation of Escherichia coli on titanium oxide films. At a light intensity of 1.6 mW/cm2, TiON films reached a bacterial killing rate of about 50% in half an hour, comparable to those reported for ultraviolet light irradiated TiO2. In the range of nitrogen concentrations from 0.2 to 0.9, the bacterial killing rates showed no clear correlation with the nitrogen concentration for the TiON films.
A “Bottom-Up” Approach to Engineering Education in Nanotechnology
Authors: Lee Sang-Joon John , Allen Emily L. , He Lili 
Published: April 2011

ABSTRACTThis paper presents a pilot project for a “bottom-up” approach to reform of undergraduate engineering education in nanotechnology, supported by a planning grant from the National Science Foundation (Engineering Education and Centers, Award #0431970). A core principle is to have individuals from different disciplines be the ones not only to build concise modules, but also to share them with content developers in other disciplines under a common organized framework. This bottom-up approach is an efficient way of introducing new content in existing curricula, and is especially helpful in university environments that may have no comprehensive “experts” in nanotechnology per se. Having individuals work together to develop bottom-up pieces from their own specialized fields provides a mechanism not only for curriculum enhancement but also for faculty professional development. In this work, pilot modules are developed as new content infused into existing courses in mechanical engineering, electrical engineering, and materials engineering at San José State University. Topics span different aspects of nanoscale materials, phenomena, devices, and manufacturing, and the content is structured in a framework such that components may be packaged as modular entities. We present pilot work accomplished in this work-in-progress, with emphasis on how lessons learned can be applied to expandability and sustainability of this bottom-up approach.
Nanoscience, Nanoengineering and Nanotechnology Education at Colorado State University - Pueblo
Authors: Jaksic Nebojsa 
Published: April 2011

ABSTRACTThis work reports on the evolution of nanoscience, nanoengineering and nanotechnology (NSET) education in the Engineering Department at the Colorado State University – Pueblo (CSU-Pueblo) from 2002 to 2006. It includes both, undergraduate and graduate courses with NSET topics as well as a review of undergraduate and graduate research projects.
Efforts to Implement a PhD degree program in “Nanoscale Science” at UNC Charlotte
Authors: Poler Jordan , Donovan-Merkert Bernadette T. , Davies Angela , El-Kouedi Mahnaz , Krueger Joanna , Smith Stuart , Stokes Edward , Schmedake Thomas A. 
Published: April 2011

AbstractUNC Charlotte is a young and growing research university. Most of the Ph.D. programs on our campus have been designed to be interdisciplinary. This strategic choice was made for both economic and pedagogical reasons. At the heart of the drive for interdisciplinary degree programs is the recognition that a lack of educational diversity at the Ph.D. level is limiting for new graduates in today's research and discovery landscape. This need for educational diversity is even more acute in the sciences. We need more chemists that know more physics, and we need more physicists that know more biology, and we need more engineers that understand matter at a molecular scale.To this end, faculty in the departments of chemistry, optical sciences, mechanical engineering, and electrical engineering have designed and are implementing a new interdisciplinary Ph.D. degree in “Nanoscale Science”. Research involving nanoscale materials and phenomena requires an educational perspective far broader than traditional academic disciplines currently offer. The question is how to deliver a broad graduate education that enables each student to reach an expertise required for the Ph.D. This is the question that has driven our pedagogical development of this Nanoscale science program.The overall structure of this program will be described and compared to other current efforts in Nanoscale graduate education throughout the United States. Various novel features will be discussed, with the hope for critical feedback and discussion. Details of the educational opportunities we have designed and the method of assessment we will employ will be presented.
The Interfacial Layer between Pt/PCMO and the Bi-stable Resistive States
Authors: Pan Wei , Evans David Russell 
Published: April 2011

ABSTRACTNobel metals in contact with perovskite metal oxides, Pr1−xCaxMnO3 (PCMO) for example, have shown switching resistance values, with a couple of orders of magnitude difference, upon the stimulation of electrical pulses. In this paper, the Pt/PCMO/Pt structures were made through e-beam evaporation (Pt electrodes) and RF sputtering (PCMO films) for the switching mechanism study. Specially designed experiments along with extensive electrical characterizations were performed on the Pt/PCMO/Pt structure. The existence of a contact resistance, or an interfacial layer, between Pt electrodes and PCMO was evident by simply measuring initial resistance (R0) of the stack against PMCO film thickness. Temperature dependence of the R0 and the time-bias tests were used to study the transport mechanism in the bulk of PCMO and the interfacial layer. Above a threshold voltage, the transport changes from mainly electronic to ionic conduction especially at the interfaces, causing electrode polarization. The transient characteristics of Pt/PCMO/Pt stack, i.e. the response to the pulsing in the time domain, were characterized in the frequency domain instead through the admittance spectroscopy measurements. The temperature dependence of Cole-Cole plots were used to study the polarized interfacial layer or interface dipole polarization (IDP). This IDP layer is the origin of contact resistance and also responsible for the uni-polar long-short switching because the calculated relaxation time constants of the IDP corresponding to low resistive state (LRS) and high resistive state (HRS) were similar to the experimental values. Therefore, the so-called bi-stable resistive states are just two different IDP states: one is much leakier than the other.
Preparation of Perovskite Conductive LaNiO3 Films by Sol-Gel Techniques
Authors: Lai Pei-Ying , Chen Jen-Sue 
Published: April 2011

ABSTRACTMetallic thin films of LaNiO3 (LNO) have been prepared by the sol-gel method using lanthanum nitrate [La(NO3)3·6H2O] and nickel acetate [Ni(CH3COO)2·4H2O] as raw materials. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrical measurements were used to characterize the multilayer LNO thin films. The perovskite phase appears after annealing at temperatures above 600 °C. LNO thin films are n-type metallic oxide. The lowest resistivity is 621 °Ω-cm after annealing at 600 °C, and the carrier concentration is 6.09×1022/cm3.
Plasma Synthesis and Surface Passivation of Silicon Quantum Dots with Photoluminescence Quantum Yields higher than 60%
Authors: Mangolini Lorenzo , Jurbergs David , Rogojina Elena , Kortshagen Uwe 
Published: April 2011

ABSTRACTSilicon nanocrystals with diameters of less than 5 nm show efficient room temperature pho-toluminescence (PL). Previous reports of PL quantum yields for ensembles of silicon quantum dots have usually been in the few percent range, and generally less than 30%. Here we report the plasma synthesis of silicon quantum dots and their subsequent wet-chemical surface passivation with organic ligands while strictly excluding oxygen. Photoluminescence quantum yields as high as 62% have been achieved at peak wavelengths of about 789 nm.
Metal-Insulator Phase Transition in VO2: A Look from the Far Infrared Side
Authors: Jepsen Peter Uhd , Fischer Bernd M. , Thoman Andreas , Helm Hanspeter , Suh J. Y. , Lopez Rene , Hanglund Richard F. 
Published: April 2011

ABSTRACTVanadium dioxide (VO2) displays a well-known metal-insulator (MI) transition at a temperature of 68°C. In this study we use terahertz time-domain spectroscopy (THz-TDS) to investigate the optical properties of VO2 thin films in the vicinity of the MI transition temperature in the frequency range 0.1 – 1.5 THz. We observe the interesting effect that the phase of the transmitted THz field through the conducting VO2 film is delayed in comparison to the phase of the same THz signal transmitted through the insulating VO2 film. This is in contrast to the expected behavior of a homogeneous, conducting film. This observation shows that even at temperatures significantly above the transition temperature, the formation of a homogeneous, conducting film is incomplete. We demonstrate that effective-medium theory (EMT) in combination with a Drude model accounting for the conductivity of metallic domains formed in the VO2 film accounts for all our observations. We show that the Maxwell-Garnett EMT is consistent with our observations, whereas the Bruggeman EMT fails to account for our observations.
Generation of Strong Short Terahertz Pulses via Stimulated Raman Adiabatic Passage-assisted Coherent Scattering
Authors: Kalugin Nikolai , Rostovtsev Yuri , Scully Marlan O. 
Published: April 2011

ABSTRACTWe analyzed the efficiency of coherent scattering of infrared radiation in atomic and molecular gases for production of intense short THz pulses, using simulated Raman adiabatic passage (STIRAP). The method is based on excitation of maximal coherence when the system is undergoing through STIRAP in IR-irradiated atomic or molecular gases (for example Rb, methanol, and others) at room temperature. By applying optical pulses in correct sequence one can generate coherence in a system during STIRAP which triggers following coherent scattering of infra-red radiation, and can produce pulses of THz radiation with pulse energies ranging from several nJ to µ-J and pulse durations from several fs to ns.
Spin-on Gate Dielectric Materials for Next Generation Display Systems
Authors: Chen Jinghong , Stifanos Mehari , Nedbal Jan , Krishnamoorthy Ahila , Brouk Emma , Smith Pete , Daniels Brian 
Published: April 2011

ABSTRACTWe present recent advances on spin-on polymers as gate dielectric for thin film transistors. We have developed film type I with significantly improved dielectric properties. At a curing temperature of 250 °C, the dielectric constant is 3.46, the breakdown voltage is 4.10 MV/cm at 1 μA/cm2, the leakage current is 4.9 × 10−8 A/cm2 at 2.5 MV/cm, and the CV hysteresis is 3.4 V. At a curing temperature of 425 °C, the dielectric constant, the breakdown voltage, the leakage current, and the CV hysteresis are 3.2, 4.73 MV/cm, 2.6 × 10−8 A/cm2, and 0.44 V respectively.
Transport Properties of Stretch-Oriented PPV Films
Authors: Wilson Tiffany , Doty F. Patrick , Chinn Douglas , Talin A. Alec , King Michael , Hunter Luke L. , Jones Frank E. , Cuppoletti Christine , Rouchanian H. , Munoz C. 
Published: April 2011

ABSTRACTOrganic semiconductors are under investigation for radiation sensors at Sandia National Laboratories. The wide band gaps, high resistivities, low dielectric constants, and high dielectric strengths of conjugated polymers suggest these materials may be suitable for solid-state particle counting detectors. A range of solution cast materials have been evaluated for this application, including polythiophenes and poly(p-phenylene vinylene)s, or PPVs.Films were prepared by novel solution casting and mechanical stretching methods. Device structures including interdigital metal electrodes on glass and thin film transistors on SiO2 on silicon were fabricated by drop casting from solution and lamination of solid films. Transient and DC responses were recorded and analyzed. Experiments include laser stimulus for photoconductive pulse response, and field effect transistor testing. Mechanical stretching was shown to dramatically alter electrical properties of polymer films.Future work will analyze the feasibility of single particle detection and analyze various geometries for optimization. The effects of traps and methods for reduction of trapping effects will be analyzed.
Synthesis and Characterization of Dendritic Architecture Containing Push-Pull Conjugated Organic Chromophore Possessing Nonlinear Optical Property
Authors: Choi Jin Joo , Lim Jong Sun , Lee Changjin , Kim Dong Wook 
Published: April 2011

ABSTRACTWe designed and synthesized a dendritic architecture in which three branches of the NLO-active component consisting of push-pull type conjugated structure were linked onto its core. Chemical structure of the dendritic nonlinear optical (NLO) chromophore was verified by NMR spectroscopy, which clearly showed that the conjugated bridge had a trans-conformation. The dendrimer exhibited that the broad absorption band centered at around 608 nm extending to 760 nm. It was thermally stable up to 275 °C in the nitrogen atmosphere. Polymer film was prepared by spincoating the solution of mixture of amorphous polycarbonate (APC) and the dendritic chromophore, which exhibited an electro-optic coefficient of 19 pm/V at 1.55 μm wavelength.
Flexible Polymer Thin-Film Transistor Device Structures And Processes For 13.56 MHz RF Rectifier Circuits
Authors: Mohapatra Siddharth , Rotzoll Robert , Jenkins Patrick , Olariu Viorel , Grigas Michelle , Wenz Robert , Dimmler Klaus , Dodabalapur Ananth 
Published: April 2011

ABSTRACTPolymeric thin-film transistors (TFTs) have been proposed for several applications including displays, electronic paper, chemical sensors, and radio-frequency identification (RFID) tags. One important technical hurdle that has to be overcome for using organic transistors in RFID tags is for these devices to operate at RF frequencies (typically 13.56 MHz) in the front end. It was long thought that conjugated polymer transistors are too slow for this. In this presentation we will demonstrate that polymer transistor based full-wave rectifier circuits utilizing a polythiophene, a p-channel semiconductor, can operate at this frequency with a useful efficiency. In order to achieve such high-frequency operation, we make use of the non-quasi static (NQS) state of the transistors. Bottom gate and top gate structures are explored and a comparison is made between the observed electrical properties. These circuits are fabricated on PEN (polyethylenenapthalate) or PET (polyethylene-terepthalate) substrates using a spin on dielectric. Gate, source and drain contacts are defined photolithographically using evaporated gold as the metal. Field-effect mobilities in the range of 0.02 and 0.2 cm2/Vs that equal or exceed the highest reported among the ones employing similar geometries on plastic substrates are easily obtained in these systems. In order for NQS based rectification to take place the carrier velocity in a 2 micrometer channel length device needs to be more than 2×104 cm/s. This would correspond to a mobility of 0.1cm2/V-s at a field of 105 V/cm. The rectifiers were based on a 4-transistor full-wave design. A coil (transformer secondary) drives the AC inputs in differential mode. The lower diode connected transistors in a manner similar to the half-wave rectifier define the DC voltage level of the two AC input signals. The two upper transistors are connected as switches and are used to move current from the AC inputs to the positive DC output. The capacitor is used to hold the peak voltage level supplied by the coil through the switch-connected devices. The voltage rectification efficiency is relatively high being as much as 45% at 13.56 MHz. This is among the fastest polymer transistor circuit of any kind demonstrated to date.
A WORM-Type Memory Device with Rectifying Effect Based on a Conjugated Copolymer of PF6Eu on Si Substrate
Authors: Tan Yoke Ping , Ling Q.D , Teo Eric Y.H , Song Y. , Lim S.L , Patrick G.Q Lo , Kang E. T , Zhu Chunxiang , Chan D.S.H 
Published: April 2011

ABSTRACTWe report a non-volatile, write-once-read-many times (WORM) memory device based on a simple organic-inorganic heterojunction. The organic film used is 9, 9-dihexylfluorene and Eu-complexed benzoate (PF6Eu (DBM)), which contains both electron-donor (9, 9-dihexylfluorene) and electron-acceptor (europium complex) groups. The inorganic n-type silicon substrate is used as the bottom electrode, while the Al is used as the top electrode. Under current-voltage testing, the device is able to switch from one initial non-conducting state (OFF) to a conducting state (ON) once a threshold voltage is reached under the first positive sweep. The “OFF” state is not recoverable with subsequent negative sweep after the device is turned “ON”. The ON/OFF current ratio is around 4×104. Diode rectifying characteristics is also observed for the turned-on device with a current ratio of 7×104, which is essential to address one memory cell in large passive matrix circuits. Reliability test is carried out and the device is able to sustain its “ON” state for at least 12 hours without any external bias.
A New Top Gate Pentacene Organic Thin Film Transistor Employing Vapor Deposited Polyimide as A Gate Dielectric
Authors: Han Chang-Wook , Park Sang-Geun , Kim Chang-Yeon , Han Min-Koo , Hyung Gun-Woo , Lee Dong-Hyun , Pyo Sang-Woo , Kim Young Kwan 
Published: April 2011

ABSTRACTA top gate pentacene TFT employing vapor deposited polyimide as a gate dielectric was fabricated. Polyimide was co-evaporated from 6FDA and ODA monomers and annealed at 150 °C in vacuum. The degree of imidization was verified by FT-IR. A breakdown voltage of 0.9 MV/cm of polyimide film was measured by MIM structure. A top gate pentacene TFT with W/L=25 has 0.01 cm2/Vs as a mobility, about 103 as an on-off ratio (In/off), −7.5V as a threshold voltage and 9 V per decade as a sub-threshold slope.
A Novel Fabrication Technique for Developing Metal Nanodroplet Arrays
Authors: Edgar Christopher , Johns Chad , Islam M. Saif 
Published: April 2011

ABSTRACTMetal patterned lines on a substrate have been annealed and broken down into isolated linear arrays of alloyed metal nanoscale droplets. These droplets are selectively fabricated across large-scale areas by controlling the location metal is present on a substrate. The metal instability and formation into nanoscale particles forms similar to studies in Rayleigh Instability of metal at an elevated temperature. Experimental results discussed here show a change in droplet diameter and formation by controlling the metal width.
Functionalized Luminescent Oxide Nanoparticles as Biological Probes
Authors: Giaume Domitille , Casanova Didier , Lahlil Khalid , Sauviat Martin-Pierre , Alexandrou Antigoni , Gacoin Thierry , Boilot Jean-Pierre 
Published: April 2011

ABSTRACTSynthesis and functionalization of nanoparticles of yttrium vanadate doped with europium is described. Synthesis of yttrium vanadate leads to ovoid nanoparticles, with an average size of 24 nm. These nanoparticles are unstable in water, and surface charge can be brought by silicate, as proven by PCS, Zetametry and IR analyses. The nanoparticle surface is then functionalized with glycidoxypropyltrimethoxysilane. The rafting is characterized by 29Si MAS NMR, and ThermoGravimetric Analyses. This alkoxysilane presents an epoxy function which can then react with a nucleophilic molecule. The functionalization is studied by 29Si MAS NMR and TGA, whereas opening of the epoxy ring is studied by 13C MAS NMR. As an example of further reactivity, we chose to graft on the nanoparticles the active part of saxitoxin, a guanidinium group. This last functionalization is proven by optical experiments performed on a cell in biological conditions.
Microbial Synthesis of Noble Metal Nanoparticles using Metal-reducing Bacteria
Authors: Konishi Yasuhiro , Ohno Kaori , Saitoh Norizoh , Nomura Toshiyuki , Nagamine Shinsuke 
Published: April 2011

ABSTRACTMicrobial synthesis of gold nanoparticles was achieved at 25°C and pH 7-1 using the mesophilic bacteriumShewanella algaewith H2as the electron donor. The microbial synthesis of gold nanoparticle was a fast process: 1 mM AuCl4−ions were completely reduced to insoluble gold within 30 min. At the solution pH 7, the gold nanoparticles of 10-20 nm were synthesized in the periplasmic space ofS. algaecells. When the solution pH was decreased to 1, the gold nanoparticles of 50-500 nm were precipitated extracellularly. The solution pH was an important factor in controlling the morphology of biogenic gold particles and location of gold deposition.
Study of PV Module Methylmetacrylate Encapsulation
Authors: Karabanov Sergey , Kukhmistrov Yuri 
Published: April 2011

ABSTRACTThe paper deals with the study of PV module encapsulation using liquid methylmetacrylate composition hardened by UV radiation. The solar cells encapsulation method by methylmetacrylate composition in the glass-glass and glass PET-foil constructions of PV modules is investigated. The UV hardening modes of methylmetacrylate composition are investigated and developed. The studied method allows to eliminate heating during encapsulation and reduce the PV module production cost. The new method makes it possible to encapsulate solar cells on any substrates, including easily melted polymeric ones, and also in the glass-glass construction.The structure and technological modes of liquid methylmetacrylate composition hardening during encapsulation have been investigated and selected. PV modules investigation for the resistance to external actions according to IEC61215 standard procedure provided positive results
Superconducting characteristics of MgB2 wires obtained by Reactive Liquid Mg Infiltration
Authors: Giunchi Giovanni , Ripamonti Giovanni , Perini Elena , Cavallin Tommaso , Bassani Enrico , Gambardella Umberto , Yang Yifeng , Young Edward A. , Bianchetti Marco , Beduz Carlo 
Published: April 2011

AbstractSuperconducting MgB2 wires, of different diameter and length, have been produced by the reactive Liquid Mg Infiltration process, also implemented with the addition of extra Mg, to completely fill the internal hole created from the normal infiltration process. The actual wires have an Iron external lining and the metallic Mg internally added has a twofold effect: to avoid Mg deficiency during the reaction and to increase the quenching resistance of the wire. The superconducting characteristics of the wires have been measured either at the liquid He and at the liquid Ne temperatures, on small samples cut from meter long wires. The typical critical current density in self field, at 27.1 K, is about 1000 A/mm2, a value of interest for many power applications. The extension of the manufacturing process to longer wire will be discussed as well as the effect of the metallic lining of the wires on the contact resistance and on the current injection length.