We report a novel method for producing aligned ZnO nanorods (ANR) on self-grown ZnO template in a... more We report a novel method for producing aligned ZnO nanorods (ANR) on self-grown ZnO template in a single step process involving growth of ZnO by vapor transport, followed by quenching of growing ZnO flux in liquid nitrogen. In the present study Zn powder turns into ZnO sheet under oxygen flow at ∼900 • C and bottom surface of the sheet acts as template for the growth of ANR. It is revealed from XRD and EDAX analysis that the bottom of the sheet is Zn rich region and acts as self catalyst for the growth of ANR. The grown nanorods have length up to several tens of micrometers with diameters ranging from ∼100 to 150 nm. Microstructural analysis of ANR indicates the fractal like configuration. The field emission properties have been investigated for ANR with fractal geometry using the ANR on self-grown ZnO template as a cathode directly. The turn-on electric field required to draw current density of ∼1.0 A/cm 2 has been found to be ∼0.98 V/m. The field enhancement factor based on Fowler-Nordheim (F-N) plot was found to be ∼7815 for ANR. The fractal geometry of ANR has been shown to be advantageous for achieving improved field emission features. The present investigations of synthesis involving formation of ANR over self-grown ZnO template, together with fractal configuration of the as-synthesized ANR, are first of their type.
Bioinformatics/computer Applications in The Biosciences, 2005
Motivation: Missing data in genotyping single nucleotide polymorphism (SNP) spots are common. Hig... more Motivation: Missing data in genotyping single nucleotide polymorphism (SNP) spots are common. High-throughput genotyping methods usually have a high rate of missing data. For example, the published human chromosome 21 data by contains about 20% missing SNPs. Inferring missing SNPs using the haplotype block structure is promising but difficult because the haplotype block boundaries are not well-defined. Here we propose a global algorithm to overcome this difficulty. Results: First, we propose to use entropy as a measure of haplotype diversity. We show that the entropy measure combined with a dynamic programming algorithm produces better haplotype block partitions than other measures. Second, based on the entropy measure, we propose a two-step iterative partition-inference (IPI) algorithm for the inference of missing SNPs. At the first step, we apply the dynamic programming algorithm to partition haplotypes into blocks. At the second step, we use an iterative process similar to the expectation-maximization (EM) algorithm to infer missing SNPs in each haplotype block so as to minimize the block entropy. The algorithm iterates these two steps until the total block entropy is minimized. We test our algorithm in several experimental data sets. The results show that the global approach significantly improves the accuracy of the inference. Availability: Upon request Contact: [email protected]
Low cost anode materials having a high electrochemical efficiency have been critical in the succe... more Low cost anode materials having a high electrochemical efficiency have been critical in the success of thin film batteries that are applicable in ubiquitous environments as a portable energy source. Nichrome thin films are ideally suited for use in hybrid assemblies but their applications include precision integrated circuits in fields of telecommunications, instrumentation, power supplies, military and medical equipment where low noise and good power dissipation are required. With such a wide spectrum of applications, it is important to understand the electric behavior of the Nichrome alloy thin films by their microstructure. In this work, nanocrystalline films of nickel chromium alloys were deposited on alumina substrate by radio frequency (RF) magnetron sputtering technology. High purity nickel and chromium sputtering target were used for the deposition. First, aluminum was deposited on ceramic substrate acts as a current collector and over that NiCr was deposited by RF sputtering method. Both the layers were analyzed for structural and electrical properties using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry. The XRD peak confirms that deposited NiCr and Aluminum have tetragonal and cubic structures, respectively. The crystallite size was determined by full width at half maximum of XRD peaks. Structure, composition and the properties of the film are the major focus of this paper. Composition ratio between nickel and chrome obtained by EDS is 1:1. Particle size and microstructure of the film have been studied by SEM and AFM. Electrochemical properties of the films were analyzed. Reaction mechanism for the insertion and excretion is reported. After Lithium insertion and extraction the effect on the surface and structure of the thin film has been studied. The composition of equilibrium phases of NiCr as useful as attracting anode for the thin film battery. Nichrome on aluminum thin films as an anode has been attracted because it provides practical advantages including low cost production and competitive electrical performance.
We study the role of electron correlations among Co 3d electrons contributing to the conduction b... more We study the role of electron correlations among Co 3d electrons contributing to the conduction band of a Kondo lattice compound, Ce2CoSi3, using high resolution photoemission spectroscopy and ab initio band structure calculations. Experimental results reveal signature of Ce 4f states derived Kondo resonance feature at the Fermi level and dominance of Co 3d contributions at higher binding energies in the valence band. The line shape of the experimental Co 3d band is found to be significantly different from that obtained from the band structure calculations within the local density approximations. Consideration of electron-electron Coulomb repulsion among Co 3d electrons leads to a better representation of experimental results. The correlation strength among Co 3d electrons is found to be about 3 eV. Signature of electron correlation induced satellite feature is also observed in the Co 2p core level spectrum. Thus, these results demonstrate the importance of the electron correlation among conduction electrons to derive the microscopic description of such Kondo systems.
Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03,... more Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03, from depositing in pipes and boilers. This treatment technique remains controversial, mostly b e c a u s e there is not an accepted scientific explanation for how the devices might work-if indeed they work at all. We have investigated several mechanisms via which magnetic water treatment devices could conceivably work.
Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03,... more Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03, from depositing in pipes and boilers. This treatment technique remains controversial, mostly b e c a u s e there is not an accepted scientific explanation for how the devices might work-if indeed they work at all. We have investigated several mechanisms via which magnetic water treatment devices could conceivably work.
We report a novel method for producing aligned ZnO nanorods (ANR) on self-grown ZnO template in a... more We report a novel method for producing aligned ZnO nanorods (ANR) on self-grown ZnO template in a single step process involving growth of ZnO by vapor transport, followed by quenching of growing ZnO flux in liquid nitrogen. In the present study Zn powder turns into ZnO sheet under oxygen flow at ∼900 • C and bottom surface of the sheet acts as template for the growth of ANR. It is revealed from XRD and EDAX analysis that the bottom of the sheet is Zn rich region and acts as self catalyst for the growth of ANR. The grown nanorods have length up to several tens of micrometers with diameters ranging from ∼100 to 150 nm. Microstructural analysis of ANR indicates the fractal like configuration. The field emission properties have been investigated for ANR with fractal geometry using the ANR on self-grown ZnO template as a cathode directly. The turn-on electric field required to draw current density of ∼1.0 A/cm 2 has been found to be ∼0.98 V/m. The field enhancement factor based on Fowler-Nordheim (F-N) plot was found to be ∼7815 for ANR. The fractal geometry of ANR has been shown to be advantageous for achieving improved field emission features. The present investigations of synthesis involving formation of ANR over self-grown ZnO template, together with fractal configuration of the as-synthesized ANR, are first of their type.
Bioinformatics/computer Applications in The Biosciences, 2005
Motivation: Missing data in genotyping single nucleotide polymorphism (SNP) spots are common. Hig... more Motivation: Missing data in genotyping single nucleotide polymorphism (SNP) spots are common. High-throughput genotyping methods usually have a high rate of missing data. For example, the published human chromosome 21 data by contains about 20% missing SNPs. Inferring missing SNPs using the haplotype block structure is promising but difficult because the haplotype block boundaries are not well-defined. Here we propose a global algorithm to overcome this difficulty. Results: First, we propose to use entropy as a measure of haplotype diversity. We show that the entropy measure combined with a dynamic programming algorithm produces better haplotype block partitions than other measures. Second, based on the entropy measure, we propose a two-step iterative partition-inference (IPI) algorithm for the inference of missing SNPs. At the first step, we apply the dynamic programming algorithm to partition haplotypes into blocks. At the second step, we use an iterative process similar to the expectation-maximization (EM) algorithm to infer missing SNPs in each haplotype block so as to minimize the block entropy. The algorithm iterates these two steps until the total block entropy is minimized. We test our algorithm in several experimental data sets. The results show that the global approach significantly improves the accuracy of the inference. Availability: Upon request Contact: [email protected]
Low cost anode materials having a high electrochemical efficiency have been critical in the succe... more Low cost anode materials having a high electrochemical efficiency have been critical in the success of thin film batteries that are applicable in ubiquitous environments as a portable energy source. Nichrome thin films are ideally suited for use in hybrid assemblies but their applications include precision integrated circuits in fields of telecommunications, instrumentation, power supplies, military and medical equipment where low noise and good power dissipation are required. With such a wide spectrum of applications, it is important to understand the electric behavior of the Nichrome alloy thin films by their microstructure. In this work, nanocrystalline films of nickel chromium alloys were deposited on alumina substrate by radio frequency (RF) magnetron sputtering technology. High purity nickel and chromium sputtering target were used for the deposition. First, aluminum was deposited on ceramic substrate acts as a current collector and over that NiCr was deposited by RF sputtering method. Both the layers were analyzed for structural and electrical properties using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry. The XRD peak confirms that deposited NiCr and Aluminum have tetragonal and cubic structures, respectively. The crystallite size was determined by full width at half maximum of XRD peaks. Structure, composition and the properties of the film are the major focus of this paper. Composition ratio between nickel and chrome obtained by EDS is 1:1. Particle size and microstructure of the film have been studied by SEM and AFM. Electrochemical properties of the films were analyzed. Reaction mechanism for the insertion and excretion is reported. After Lithium insertion and extraction the effect on the surface and structure of the thin film has been studied. The composition of equilibrium phases of NiCr as useful as attracting anode for the thin film battery. Nichrome on aluminum thin films as an anode has been attracted because it provides practical advantages including low cost production and competitive electrical performance.
We study the role of electron correlations among Co 3d electrons contributing to the conduction b... more We study the role of electron correlations among Co 3d electrons contributing to the conduction band of a Kondo lattice compound, Ce2CoSi3, using high resolution photoemission spectroscopy and ab initio band structure calculations. Experimental results reveal signature of Ce 4f states derived Kondo resonance feature at the Fermi level and dominance of Co 3d contributions at higher binding energies in the valence band. The line shape of the experimental Co 3d band is found to be significantly different from that obtained from the band structure calculations within the local density approximations. Consideration of electron-electron Coulomb repulsion among Co 3d electrons leads to a better representation of experimental results. The correlation strength among Co 3d electrons is found to be about 3 eV. Signature of electron correlation induced satellite feature is also observed in the Co 2p core level spectrum. Thus, these results demonstrate the importance of the electron correlation among conduction electrons to derive the microscopic description of such Kondo systems.
Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03,... more Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03, from depositing in pipes and boilers. This treatment technique remains controversial, mostly b e c a u s e there is not an accepted scientific explanation for how the devices might work-if indeed they work at all. We have investigated several mechanisms via which magnetic water treatment devices could conceivably work.
Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03,... more Magnetic water treatment devices have been used for many years to prevent scale, primarily CaC03, from depositing in pipes and boilers. This treatment technique remains controversial, mostly b e c a u s e there is not an accepted scientific explanation for how the devices might work-if indeed they work at all. We have investigated several mechanisms via which magnetic water treatment devices could conceivably work.
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