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2002

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Articles 1 - 23 of 23

Full-Text Articles in Nanoscience and Nanotechnology

Detection And Analysis Of Sec1 Immunological Reaction By Afm And Electrochemical Method, Sa-Ying Dong, Hong-Ren Wang Nov 2002

Detection And Analysis Of Sec1 Immunological Reaction By Afm And Electrochemical Method, Sa-Ying Dong, Hong-Ren Wang

Journal of Electrochemistry

The goals of this work were to demonstrate the ability of atomic force microscopy (AFM) to detect various immunological processes between antibodies and antigens.A sensor was designed by covalently linking the antibody of staphylococcal enterotoxin Cl (SEC1) on the self-assembled gold surface. This sensor permitted detection of antibody-antigen recognition events which were highly correlated with the topography under different conditions. The statistic data of AFM were analysed. As control experiments, nonspecific antigens and lower concentration SEC1 antigens were directly observed. In addition, an acidic solution was used to break the antigen-antibody pair and made the sensor reuse. Electrochemical evidence was …

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Preparation And Electrochemical Lithium Intercalation Performance Of Different Shaped Carbon Nanotube, Mao-Hui Chen, Zhen-Cai Huang, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin Nov 2002

Preparation And Electrochemical Lithium Intercalation Performance Of Different Shaped Carbon Nanotube, Mao-Hui Chen, Zhen-Cai Huang, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

In the present work, different shaped carbon nanotubes were produced by the general CVD and the template method at different temperature (600 ℃,700 ℃) with the reaction gas of acetylene. The morphology, structure and the electrochemical lithium intercalation performance were comparatively studied and characterized by TEM, HRTEM, SEM, XRD, Raman techniques and Charge/Discharge Test. It was found that the different preparation methods and temperatures all had an obvious effect on these properties of carbon nanotubes. In our samples, with the increase of preparation temperature, the degree of crystallinity decreased, and the reversible specific capacity increased respectively.

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Nano-Sized Cobalt-Based Oxides As Negative Electrode For Lithium-Ion Batteries, Feng Huang, Zheng-Yong Yuan, Yun-Hong Zhou, Ju-Tang Sun Nov 2002

Nano-Sized Cobalt-Based Oxides As Negative Electrode For Lithium-Ion Batteries, Feng Huang, Zheng-Yong Yuan, Yun-Hong Zhou, Ju-Tang Sun

Journal of Electrochemistry

Nanosized cobalt-based oxide (Co3O4, CoB1.36O2.8 and CoB0.5Al0.1O1.5) samples were prepared by rheological phase method and were tested as anodes in secondary lithium batteries. The cells were cycled between 0.01V and 3.00 V. The best electrochemical performance was obtained from the Co3O4 cell, which retained 95% of its initial capacity (931 mAh/g) after 30 cycles. The doping of B, Al reduced the reversible capacity during the first discharge/charge cycle, and the quantity of reversible capacity reduced with B, Al increasing. The modifying structures at difference …

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Electrochemical Preparation And Reaction Mechanism Of Nanocrystalline Nio, Jia-Shan Gu, Ai-Jie Han, Xing-Fu Zhou, Dao-Bao Chu, Chang-Jian Lin Nov 2002

Electrochemical Preparation And Reaction Mechanism Of Nanocrystalline Nio, Jia-Shan Gu, Ai-Jie Han, Xing-Fu Zhou, Dao-Bao Chu, Chang-Jian Lin

Journal of Electrochemistry

Metallic nickel was electrochemically dissolved in absolute ethanol and acetylacetone mixed solutions and in the presence of Bu4NBr (as an electron-conductive additive). The electrolyte solution containing the precursor was then directly hydrolyzed to obtain nanocrystalline NiO. The precursor was characterized by FTIR, HNMR, Raman spectra and the nano-powder was characterized by XRD and TEM. The results showed that the NiO powder after calcined at 450 ℃ had formed the cubic NaCl structure and the nanocrystalline NiO prepared by this method had narrow size distribution of 10～15 nm. Moreover, the product yield could be improved by controlling temperature below …

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Multiscale Nature Of Hysteretic Phenomena: Application To Copt-Type Magnets, Kirill D. Belashchenko, Vladimir P. Antropov Oct 2002

Multiscale Nature Of Hysteretic Phenomena: Application To Copt-Type Magnets, Kirill D. Belashchenko, Vladimir P. Antropov

Nebraska Center for Materials and Nanoscience: Faculty Publications

We suggest a workable approach for the description of multiscale magnetization reversal phenomena in nanoscale magnets and apply it to CoPt-type alloys. We show that their hysteretic properties are governed by two effects originating at different length scales: a peculiar splitting of domain walls at twin boundaries and their strong pinning at antiphase boundaries. We emphasize that such multiscale nature of hysteretic phenomena is a generic feature of nanoscale magnetic materials.

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Rectangular Bursting Energy Absorber, John D. Reid, John R. Rohde, Dean L. Sicking Oct 2002

Rectangular Bursting Energy Absorber, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A bursting energy absorber System having an impact head, and energy absorption mechanism. The energy absorbing mechanism has a generally rectangular mandrel for rupturing cooperating thin-walled generally rectangular tubes in a controlled rupture to absorb impact forces for a colliding vehicle. A frame may be used to mount the System to a truck, trailer, guardrail, median barrier end treatment, or a crash cushion. Stress concetrators such as saw cuts or scoring may be incorporated into the absorption tubes to selectively control rupturing and energy dissipation. The mandrels may be tapered, rectangulary shaped with beveled edges to reduce frictional forces along …

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In Situ Corrosion Studies On The Battleship Uss Arizona, John D. Makinson, James D. Carr, Matthew A. Russell, David L. Conlin, Larry E. Murphy Sep 2002

In Situ Corrosion Studies On The Battleship Uss Arizona, John D. Makinson, James D. Carr, Matthew A. Russell, David L. Conlin, Larry E. Murphy

Department of Mechanical and Materials Engineering: Faculty Publications

U.S. National Park Service Submerged Resources Center archaeologists and University of Nebraska-Lincoln metallurgists are assessing hull corrosion by drilling through accumulated concretions and measuring pH and corrosion potentials. Concretion samples are being analyzed to determine the role of microbes in the corrosion process, identify chemical species, and measure electrical and physical properties. The lowest values of pH and E corr occur at the metal/concretion interface. Analysis suggests a variable corrosion rate supported by hydrogen discharge and/or oxygen reduction inside the concretion.

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Facilitated K+ Ion Transfer By Db18c6 Across The Micro Liquid/Liquid Interface, Dong-Ping Zhan, Bing-Liang Wu Aug 2002

Facilitated K+ Ion Transfer By Db18c6 Across The Micro Liquid/Liquid Interface, Dong-Ping Zhan, Bing-Liang Wu

Journal of Electrochemistry

A novel microcavity Ag|AgCl electrode was fabricated to construct the micro-interface of two immiscible electrolyte solutions(ITIES). The transfer reactions of K+ ion facilitated by DB18C6 across the water/1,2-DCE interface was investigated with the three-electrodes system. The corresponding reaction parameters were derived from the voltammetric data. The results showed that the microcavity electrode would be a useful and efficient tool to investigate the charge transfer reactions at ITIES.

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Pure Hap Film Prepared By Direct Electrodepositing On Metallic Surface And Its Mechanism, Hao-Bing Hu, Chang-Jian Lin, Fei Chen, Ren Hu, Ming Guo Aug 2002

Pure Hap Film Prepared By Direct Electrodepositing On Metallic Surface And Its Mechanism, Hao-Bing Hu, Chang-Jian Lin, Fei Chen, Ren Hu, Ming Guo

Journal of Electrochemistry

In controlling concentration of Ca2+ and PO43- in electrodeposition solution, the HAP film on Ti alloy has been deposited directly. Using XRD and SEM we have learned that prepared HAP is intact in crystal and equal in dimension. Thermodynamic calculation indicated that the HAP is easer formation of than that TCP of. With the XRD, SEM analyses and thermodynamic calculation, the electrodeposition mechanism has been discussed. It was proved that electrodepositon is a two-stage process and formation of HAP is a direct process from solution ions to HAP crystal without precursor.

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Spontaneous Planarization Of Nanoscale Phase Separated Thin Film, Ravi F. Saraf, Sanjun Niu, Eric Stumb Jun 2002

Spontaneous Planarization Of Nanoscale Phase Separated Thin Film, Ravi F. Saraf, Sanjun Niu, Eric Stumb

Papers in Nanotechnology

Structure of complex fluid at mesoscales is influenced by interfacial effects. We describe the dynamic response in such films to sudden change in interfacial tension. In a self-assembled block copolymer film, the monolayer of 15 nm diam cylindrical discrete phases close to the surface commence to sink at an average rate of 0.16 nm/day in response to the interfacial tension change. Surprisingly, this spontaneous planarization occurs, even though the cylinders are covalently stitched to the matrix. A simple model explains the observed behavior. The observation may lead to approaches to tailor the structure of mesoscale thin films of complex fluids …

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Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin May 2002

Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin

Journal of Electrochemistry

A novel nanomaterial, zinc oxide (ZnO) and polyaniline (PANI) coaxial nanowires and their array in the template, was synthesized using anodic aluminum oxide (AAO) membrane as template. The morphology of these coaxial nanowires was observed with transmission electron microscope (TEM). The experiments on photoluminescence (PL) of coaxial nanowires and their array in AAO membrane show that the visible emission band of ZnO shifts from 530 nm to 400 nm and the luminescence is enhanced for the coaxial nanowires array in AAO membrane,and the visible emission band shifts to a lower wavelergth (385 nm) for coatial nanowires in NaOH solution. Possible …

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The Preparation And Characterization Of Growing Preferentially Cds Nanopartile Film, Huai-Guo Huang, Yan-Yan Xi, Zhi-Xin Zheng, Jia-Wei Yan, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin May 2002

The Preparation And Characterization Of Growing Preferentially Cds Nanopartile Film, Huai-Guo Huang, Yan-Yan Xi, Zhi-Xin Zheng, Jia-Wei Yan, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

CdS nanoparticle films were prepared on the PANI film, PATP film, Au film and ITO respectively by constant current deposition or current impulse method, and their structure and character were also studied. The results show that the substrates influence the structure and character of CdS particle film.

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Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan May 2002

Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan

Faculty Publications

A technique to perform nanofatigue experiments was developed. This technique utilizes a depth-sensing nanoindenter with harmonic force. The nanofatigue behavior of 20 nm thick amorphous carbon coatings was studied. The contact stiffness was monitored continuously throughout the test. The abrupt decrease in the contact stiffness indicates fatigue damage has occurred. The critical load amplitude, below which no fatigue damage occurs, was identified. It was found that the filtered cathodic arc coating exhibits longer fatigue life than a direct ion beam coating. Failure mechanisms of the coatings during fatigue are also discussed in conjunction with the hardness,elastic modulus, and fracture toughness, …

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Structure Of Macrodomain Walls In Polytwinned Magnets, Kirill D. Belashchenko, Vladimir P. Antropov May 2002

Structure Of Macrodomain Walls In Polytwinned Magnets, Kirill D. Belashchenko, Vladimir P. Antropov

Nebraska Center for Materials and Nanoscience: Faculty Publications

We propose a microscopic approach to the studies of magnetic configurations in hard magnets which may be conveniently used for nanoscale systems; the microstructure of the magnet is easily and naturally included in the calculations. This approach is applied to find the structure of macrodomain walls in polytwinned magnets of the CoPt family. Magnetostatic fields are small compared to the anisotropy field in these magnets; direct simulation shows that in this case the macrodomain wall is not continuous, but rather comprised of segments held together by relatively small magnetostatic forces. This segmentation is expected to have a strong effect on …

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Magnetization Reversal Of Individual Nanowires With Controlled Defects, Andrei Sokolov, Renat F. Sabirianov, W. Wernsdorfer, Bernard Doudin May 2002

Magnetization Reversal Of Individual Nanowires With Controlled Defects, Andrei Sokolov, Renat F. Sabirianov, W. Wernsdorfer, Bernard Doudin

Nebraska Center for Materials and Nanoscience: Faculty Publications

Low temperature magnetization reversal measurements were performed on individual permalloy nanowires of diameters between 30 and 60 nm. During the electrochemical growth of the wire, a defect was induced by a short pulse in the deposition potential modifying locally the microstructure and composition. Magnetic measurements performed with micro-superconducting quantum interference devices were performed. The angular dependence of switching field revealed significant deviations from classical predictions. For specific angles, magnetization curves indicate a reversal occurring in two steps.

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Performance Projections For Ballistic Carbon Nanotube Field-Effect Transistors, Jing Guo, Mark Lundstrom, Supriyo Datta Apr 2002

Performance Projections For Ballistic Carbon Nanotube Field-Effect Transistors, Jing Guo, Mark Lundstrom, Supriyo Datta

Other Nanotechnology Publications

The performance limits of carbon nanotube field-effect transistors 􏰎CNTFETs􏰁 are examined theoretically by extending a one-dimensional treatment used for silicon metal – oxide – semiconductor field-effect transistors 􏰎MOSFETs􏰁. Compared to ballistic MOSFETs, ballistic CNTFETs show similar I–V characteristics but the channel conductance is quantized. For low-voltage, digital applications, the CNTFET with a planar gate geometry provides an on-current that is comparable to that expected for a ballistic MOSFET. Significantly better performance, however, could be achieved with high gate capacitance structures. Because the computed performance limits greatly exceed the performance of recently reported CNTFETs, there is considerable opportunity for progress in …

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Photocurrent Enhancement By Ticl4 Post-Treatment For Tio2 Nanoporous Film Electrode, Yan-Jie Ren, Li Zhang, Sheng-Min Cai Feb 2002

Photocurrent Enhancement By Ticl4 Post-Treatment For Tio2 Nanoporous Film Electrode, Yan-Jie Ren, Li Zhang, Sheng-Min Cai

Journal of Electrochemistry

Enhanced photocurrent in dye-sensitized photoelectrochemical cell was obtained by post-treating the TiO2 nanoporous film electrode with TiCl4. By investigating the effect of the post-treatment on surface area, pore size distribution, laser pulse induced current transient of the film electrode, photocurrent increase by the post-treatment was assigned to the improved electron percolation resulting from broadening of interparticle neck.

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Raman Spectroscopic Study On Mechanism Of Aluminum Triphosphate Pigment, Zhi-Jun Gu, Yong-Gui Liao, Zhi-Gang Zhang, Qi-Long Guo, Fang-Teng Su Feb 2002

Raman Spectroscopic Study On Mechanism Of Aluminum Triphosphate Pigment, Zhi-Jun Gu, Yong-Gui Liao, Zhi-Gang Zhang, Qi-Long Guo, Fang-Teng Su

Journal of Electrochemistry

The painted steel sample whose coating contained anticorrosive pigment has been investigated by Raman spectroscopy. The protective mechanism of aluminum triphosphate pigment for A3 steel is proposed as follows: Aluminum triphosphate can be dissolved and arrive at the surface of the steel.The dissolved triphosphate ions can complex with ferric ions.And the new products, namely ferric triphosphate, can strongly adhere at the surface of the steel by chemical bonds slowly. At last, a compact protective film, which effectively separates the steel substrate from the aggressive media, is formed at the steel surface.

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Further Evidence For Surface Properties Of Porous Silicon Resulting In Electroluminescence, Zhan-Jun Zhang, Bin Wu, Jing-Jian Li, Zhong-Fan Liu, Sheng-Min Cai Feb 2002

Further Evidence For Surface Properties Of Porous Silicon Resulting In Electroluminescence, Zhan-Jun Zhang, Bin Wu, Jing-Jian Li, Zhong-Fan Liu, Sheng-Min Cai

Journal of Electrochemistry

The electroluminescence of porous silicon in solutions at positive biases was investigated by luminescence spectrometer. The electroluminescence of porous silicon in solutions mainly depended on its surface properties. The elelctroluminescence was much enhanced when the sample of porous silicon was electrolyzed once again which had undergone an electroluminescence test. The tests of both cyclic voltammetry and the luminescence of the sample of porous silicon prepared by repeated electrolysis provided further evidence that the electroluminescence of porous silicon in solutions at positive biases stemmed from the oxidation of Si-H on the surface of porous silicon. The voltage tunable emitting for porous …

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Characterization Of Crbn Films Deposited By Ion Beam Assisted Deposition, S.M. Aouadi, F. Namavar, E. Tobin, N. Finnegan, R.T. Haasch, R. Nilchiani, Joseph A. Turner, S. L. Rohde Feb 2002

Characterization Of Crbn Films Deposited By Ion Beam Assisted Deposition, S.M. Aouadi, F. Namavar, E. Tobin, N. Finnegan, R.T. Haasch, R. Nilchiani, Joseph A. Turner, S. L. Rohde

Nebraska Center for Materials and Nanoscience: Faculty Publications

This article reports on the growth and analysis of CrBN nanocrystalline materials using an ion beam assisted deposition process. In addition, this article addresses the utilization of spectroscopic ellipsometry for in situ analysis of ternary nitrides. Coatings, with a total thickness of 1.5 ±0.2 μm, were deposited at low temperatures (<200 °C) on silicon substrates using ion beam assisted deposition. These coatings were characterized postdeposition using x-ray diffraction (XRD), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), visible-light spectroscopic ellipsometry (VIS-SE), infrared spectroscopic ellipsometry (IR-SE), and nanoindentation. The primary phases in the films were investigated using XRD. The surface morphology and nanocrystalline nature of the coatings (grain size of 5–7 nm) were deduced using AFM. The elemental composition and phase composition of the samples were determined from XPS and AES measurements and were subsequently deduced from the analysis of the VIS-SE data, and these correlated well. XPS, AES, and IR-SE revealed the crystal structure of the BN phase in the ternary compounds. The correlation of the results from these various techniques indicates that in situ SE may be a potential technique to control the growth of ternary nitride coatings in the future. The mechanical properties of the coatings were evaluated using nanohardness testing. The hardness and elastic modulus were measured to be 19–22 GPa and 250–270 GPa, respectively.

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Synthesis And Magnetic Properties Of Copt–Poly(Methylmethacrylate) Nanostructured Composite Material, Jiye Fang, Kevin L. Stokes, Jibao He, Weillie L. Zhou, Charles J. O'Connor, Daniela Caruntu Jan 2002

Synthesis And Magnetic Properties Of Copt–Poly(Methylmethacrylate) Nanostructured Composite Material, Jiye Fang, Kevin L. Stokes, Jibao He, Weillie L. Zhou, Charles J. O'Connor, Daniela Caruntu

Physics Faculty Publications

We have prepared nanometer-sized CoPt particles dispersed in a poly~methyl methacrylate~PMMA!matrix, as a novel nanostructured magnetic plastic, through a soft chemical processing route. In this work, CoPt nanoparticles were successfully synthesized from a solution phase reduction system in the presence of capping ligands and stabilizing agents at high temperature. The CoPt nanoparticles were annealed at 400 °C for 3 h, and were subsequently re-dispersed inmethylmethacrylate~monomer! . The polymerization was induced by a UV source and the hardness of final product was adjusted by varying the amount of monomeric cross-link agent. Annealed bare CoPt nanoparticles as a ‘‘core’’ material and CoPt–PMMA …

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121.6 Nm Radiation Source For Advanced Lithography, Jianxun Yan, Ashraf El-Dakrouri, Mounir Laroussi, Mool C. Gupta Jan 2002

121.6 Nm Radiation Source For Advanced Lithography, Jianxun Yan, Ashraf El-Dakrouri, Mounir Laroussi, Mool C. Gupta

Electrical & Computer Engineering Faculty Publications

A vacuum ultraviolet (VUV) light source based on a high-pressure cylindrical dielectric barrier discharge (DBD) has been developed. Intense and spectrally clean Lyman-α line at 121.6 nm was obtained by operating a DBD discharge in neon with a small admixture of hydrogen. The spectrum, optical power, stability, and efficiency of the source were measured. The influence of the gas mixture and total gas pressure on the VUV intensity has been investigated. Maximum optical power of 3.2 W and spectral width 0.03 nm was achieved. Power stability of 2% for 100 h of operation has also been obtained. The newly developed …

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Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm Jan 2002

Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

In precision manufacturing enterprises, machine parts at nonstandard temperatures are often soaked to standard temperature prior to making any dimensional measurements. The soakout times are usually determined using lumped heat-transfer models where the part temperatures are assumed to be uniform. This article discusses conditions under which lumped model assumptions are valid by comparing lumped analyses for various shapes and materials with the more general finite element results. In addition, the effect of ambient temperature cycling on part response is also studied.

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