The cationic surfactant cetyltrimethylammonium tosylate (CTAT) forms highly viscous/viscoelastic solutions and worm-like micelles at relatively low concentrations. The effect of 1-alkanols with short to long alkyl chains viz. ethanol,... more
The cationic surfactant cetyltrimethylammonium tosylate (CTAT) forms highly viscous/viscoelastic
solutions and worm-like micelles at relatively low concentrations. The effect of 1-alkanols with short to
long alkyl chains viz. ethanol, 1-butanol, 1-hexanol and 1-octanol on CTAT micelles was examined. In
particular, a detailed study on the effect of 1-hexanol was carried out by viscosity, cryogenic
transmission electron microscopy (cryo-TEM), nuclear magnetic resonance (NMR) and small-angle
neutron scattering (SANS) to observe microstructural changes in CTAT micelles. 1-Hexanol displays
a distinct interaction with CTAT micelles strongly dependent on CTAT concentration. Up to a certain
critical CTAT concentration, 1-hexanol molecules penetrate into the micelles and show growth.
Characterization by direct cryo-TEM imaging implies that upon progressive addition of 1-hexanol,
worm-like CTAT micelles first grow and finally transform into vesicles. The course of vesicle formation
was followed by SANS measurements. The site of 1-hexanol in the micelles close to the palisade layer
was evaluated using 2D NMR. This study devotes a fundamental knowledge for controlling the shape and
size of worm-like micelles that find many industrial applications particularly in personal- and home-care
products.
solutions and worm-like micelles at relatively low concentrations. The effect of 1-alkanols with short to
long alkyl chains viz. ethanol, 1-butanol, 1-hexanol and 1-octanol on CTAT micelles was examined. In
particular, a detailed study on the effect of 1-hexanol was carried out by viscosity, cryogenic
transmission electron microscopy (cryo-TEM), nuclear magnetic resonance (NMR) and small-angle
neutron scattering (SANS) to observe microstructural changes in CTAT micelles. 1-Hexanol displays
a distinct interaction with CTAT micelles strongly dependent on CTAT concentration. Up to a certain
critical CTAT concentration, 1-hexanol molecules penetrate into the micelles and show growth.
Characterization by direct cryo-TEM imaging implies that upon progressive addition of 1-hexanol,
worm-like CTAT micelles first grow and finally transform into vesicles. The course of vesicle formation
was followed by SANS measurements. The site of 1-hexanol in the micelles close to the palisade layer
was evaluated using 2D NMR. This study devotes a fundamental knowledge for controlling the shape and
size of worm-like micelles that find many industrial applications particularly in personal- and home-care
products.
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We describe the fabrication and properties of high critical current density (J c ) Nb/AlO x /Nb Josephson junctions with deep-submicron dimensions. The junctions are fabricated using a planarized process in which all levels are patterned... more
We describe the fabrication and properties of high critical current density (J c ) Nb/AlO x /Nb Josephson junctions with deep-submicron dimensions. The junctions are fabricated using a planarized process in which all levels are patterned using a combination of optical and electron beam lithography. The base and counter electrodes are defined by reactive ion etching using quartz etch masks to give a minimum feature size of 0.2 microns. For J c = 2.1 mA/m 2 and junction area less than 0.1 m 2 the devices are self-shunted and exhibit nonhysteretic IV characteristics. A small hysteresis in the larger junctions is caused by heating in the electrodes. I. INTRODUCTION Most of the applications of the Josephson effect in superconducting electronics such as SQUID based magnetic sensors, Josephson integrated circuits (ICs) (e.g., digital devices based on rapid single-flux-quantum (RSFQ) logic [1]), array oscillators [2],[3], and voltage standards [4] require Josephson junctions with nonhys...
For superconducting qubits, losses in superconducting films as well as substrates and dielectrics can play important roles in determining the coherence time. We used co-planar waveguide resonators to study the losses in Nb films and... more
For superconducting qubits, losses in superconducting films as well as substrates and dielectrics can play important roles in determining the coherence time. We used co-planar waveguide resonators to study the losses in Nb films and substrates. Resonators with quality factors as high as 6 x10^5 were fabricated and measured. We found that both the fabrication process and resistivity of the substrates contribute to the quality of the resonators and hence to the losses. With a proper fabrication process, very high quality Nb films can be made. The etching process, which is necessary for the fabrication of qubits, lowers the quality of the resonators. We are optimizing the fabrication process to reduce the losses and to increase coherence time for our qubits.
We have measured the low frequency critical current noise in Nb/AlOx/Nb Josephson junctions used for qubits in quantum computation circuits. Low frequency current noise measurements were made using a bridge circuit with a SQUID null... more
We have measured the low frequency critical current noise in Nb/AlOx/Nb Josephson junctions used for qubits in quantum computation circuits. Low frequency current noise measurements were made using a bridge circuit with a SQUID null detector. The current noise spectra density showed a 1/f component at low frequencies for both an unshunted junction biased near 6 mV and a shunted junction biased near ˜7 muV. In both cases this corresponded to critical current fluctuations with a spectral density at 1 Hz of 2.2 .10-24 A^2/Hz. Our measured value of critical current fluctuations is roughly two orders of magnitude less than the average of various technologies reported by Van Harlingen et al. (2004).
Di-tert-butyl ketone (2 a), 5, 5, 7, 7-tetramethyl-6-undecanone (2 b), and 2, 4-dimethyl-2, 4-diphenyl-3-pentanone (2 d) have been found to undergo slow rearrangement by β-proton abstraction from the α-methyl groups upon treatment with... more
Di-tert-butyl ketone (2 a), 5, 5, 7, 7-tetramethyl-6-undecanone (2 b), and 2, 4-dimethyl-2, 4-diphenyl-3-pentanone (2 d) have been found to undergo slow rearrangement by β-proton abstraction from the α-methyl groups upon treatment with t-BuO-/t-BuOH/≥ 185° C. This is ...
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In 1935, Schrodinger attempted to demonstrate the limitations of quantum mechanics using a thought experiment in which a cat is put in a quantum superposition of alive and dead states. The idea remained an academic curiosity until the... more
In 1935, Schrodinger attempted to demonstrate the limitations of quantum mechanics using a thought experiment in which a cat is put in a quantum superposition of alive and dead states. The idea remained an academic curiosity until the 1980s when it was proposed that, under suitable conditions, a macroscopic object with many microscopic degrees of freedom could behave quantum mechanically, provided that it was sufficiently decoupled from its environment. Although much progress has been made in demonstrating the macroscopic quantum behaviour of various systems such as superconductors, nanoscale magnets, laser-cooled trapped ions, photons in a microwave cavity and C60 molecules, there has been no experimental demonstration of a quantum superposition of truly macroscopically distinct states. Here we present experimental evidence that a superconducting quantum interference device (SQUID) can be put into a superposition of two magnetic-flux states: one corresponding to a few microamperes ...
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We report the observation of the universal distribution of transparencies, predicted by Schep and Bauer [Phys. Rev. Lett. 78, 3015 (1997)] for dirty sharp interfaces, in uniform Nb/AlO(x)/Nb junctions with high specific conductance (10(8)... more
We report the observation of the universal distribution of transparencies, predicted by Schep and Bauer [Phys. Rev. Lett. 78, 3015 (1997)] for dirty sharp interfaces, in uniform Nb/AlO(x)/Nb junctions with high specific conductance (10(8) ohm(-1) cm(-2)). Experiments used the BCS density of states in superconducting niobium for transparency distribution probing. Experimental results for both the dc I-V curves at magnetic-field-suppressed supercurrent and the Josephson critical current in zero magnetic field coincide remarkably well with calculations based on the multimode theory of multiple Andreev reflections and the Schep-Bauer distribution.
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ABSTRACT The flux in an rf SQUID is a macroscopic variable that exhibits quantum tunneling effects. Under suitable conditions it can be modeled as a particle in a double-well potential in which the left and right wells correspond to the 0... more
ABSTRACT The flux in an rf SQUID is a macroscopic variable that exhibits quantum tunneling effects. Under suitable conditions it can be modeled as a particle in a double-well potential in which the left and right wells correspond to the 0 and 1 flux states, respectively. The system has quantized energy levels, a few of which are localized in each well. Previous work [1] has shown that microwave radiation produces transitions between levels that result in measurable interwell transitions. We will discuss various experimental schemes for detecting Macroscopic Quantum Coherence of the flux in the SQUID via the application of controllable external microwaves. Coherent tunneling between otherwise degenerate ground states can, in principle, be detected, although there are certain advantages to attempting to establish coherence between excited states. [1] R. Rouse, S. Han and J. E. Lukens, Phys. Rev. Lett., b75, 1614 (1995).
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ABSTRACT The first two and a half years of Columbus Operation have been analysed to assess the efficiency of the failure management system. The assessment took into account two aspects. The first aspect was the fulfilment of the failure... more
ABSTRACT The first two and a half years of Columbus Operation have been analysed to assess the efficiency of the failure management system. The assessment took into account two aspects. The first aspect was the fulfilment of the failure management functions as they have been specified in the requirements document. The second aspect covered the spacecraft operation. How did the failure management meet the operational needs? In the frame of the analysis it was found, that the failure management is on one side not as sensitive and on the other not as robust as expected. In respect to the operational needs it was identified that more functionality and flexibility could enable increased autonomy of the spacecraft. This aspect is of special interest as the costs for long duration mission, like for Columbus, accumulate to an immense amount. Autonomy could help to reduce the costs. The paper presents an improved failure management concept that aims to increase the robustness, to better address the operational needs, and to enable new operational concepts for cost reduction.
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We have realized an on-chip persistent flux bias for our flux based qubit by adding a switchable aluminum shunt to the niobium flux bias coils. This inductive shunt can create a persistent current loop by trapping the bias flux at the... more
We have realized an on-chip persistent flux bias for our flux based qubit by adding a switchable aluminum shunt to the niobium flux bias coils. This inductive shunt can create a persistent current loop by trapping the bias flux at the superconducting transition of the Al. When the Al is superconducting, the noise spectral density from the flux bias and
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... Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, USA E-mail: Douglas.Bennett@sunysb.edu Received 12 June 2007, in final form 13 July 2007 Published 18 October 2007 Online at... more
... Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, USA E-mail: Douglas.Bennett@sunysb.edu Received 12 June 2007, in final form 13 July 2007 Published 18 October 2007 Online at stacks.iop.org/SUST/20/S445 ...
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This audit was commissioned to identify and review research relating to minority ethnic people in Scotland in order to inform the development of a new Scottish Executive research programme in this area. The study discusses key themes... more
This audit was commissioned to identify and review research relating to minority ethnic people in Scotland in order to inform the development of a new Scottish Executive research programme in this area. The study discusses key themes arising from the identified research, highlights significant research gaps and makes recommendations for future research. The construction of an electronic database of relevant
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Careful filtering is necessary for observations of quantum phenomena in superconducting circuits at low temperatures. Measurements of coherence between quantum states require extensive filtering to protect against noise coupled from room... more
Careful filtering is necessary for observations of quantum phenomena in superconducting circuits at low temperatures. Measurements of coherence between quantum states require extensive filtering to protect against noise coupled from room temperature electronics. We demonstrate distributed transmission line filters which cut off exponentially at GHz frequencies and can be anchored at the base temperature of a dilution refrigerator. The compact design makes them suitable to filter many different bias lines in the same setup, necessary for the control and measurement of superconducting qubits.
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The formation constants of the complexes of the type [NiAL], where A=2,2′-bipyridyl, 1,10-phenanthroline, 2-(2′-pyridyl) benzimidazole, or 2-(2′-pyridyl) imidazoline and L=ethylenediamine, 1,2-diaminopropane, N-methyl-ethylenediamine,... more
The formation constants of the complexes of the type [NiAL], where A=2,2′-bipyridyl, 1,10-phenanthroline, 2-(2′-pyridyl) benzimidazole, or 2-(2′-pyridyl) imidazoline and L=ethylenediamine, 1,2-diaminopropane, N-methyl-ethylenediamine, glycine, α-alanine, β-alanine, malonate, histidine, or histamine have been determined in dioxan-water (1∶1 v/v) medium and μ=0·2 mol dm−3 NaClO4 at 30°C. The values of ΔlogK M (logK MAL MA −logK ML M ) in Ni(II) complexes have been compared with corresponding Cu(II) complexes. It is observed that for [NiAL] complexes, where L=L1 to L7, ΔlogK is more negative than for the corresponding [CuAL] complexes whereas in cases where L=L8, or L9, ΔlogK for Ni(II) complexes is less negative than for the corresponding Cu(II) complexes. The reason has been discussed.
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... t/λ p was determined from low-loss spectra [8]. The results obtained with this method are summarized in Table 1. It can be seen that for the hydrogenated DLC films ... EELS spectroscopy has been used to analyze the structure of DLC... more
... t/λ p was determined from low-loss spectra [8]. The results obtained with this method are summarized in Table 1. It can be seen that for the hydrogenated DLC films ... EELS spectroscopy has been used to analyze the structure of DLC films. ... Diamond Films Technol., 1 (1992), p. 219 ...
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ABSTRACT Diamond-like carbon films deposited on silicon wafers by r.f.-plasma-assisted chemical vapour deposition were friction tested in controlled atmospheres in a reciprocating pin-on-plate configuration using a steel sphere. Friction... more
ABSTRACT Diamond-like carbon films deposited on silicon wafers by r.f.-plasma-assisted chemical vapour deposition were friction tested in controlled atmospheres in a reciprocating pin-on-plate configuration using a steel sphere. Friction experiments were carried out in a vacuum range from 10-7 to 50 Pa, in dry nitrogen and in ambient air. Analytical investigations of the wear process were peformed using transmission electron microscopy-electron energy loss spectroscopy and secondary ion mass spectroscopy. In all cases a transfer film was observed to form on the steel pin during the first 100 cycles, associated with relatively high values of the friction coefficient (0.2–0.3) at this stage. Beyond N=100 cycles the friction coefficient decreased to 0.006–0.008 in a vacuum below 10-1 Pa and to 0.01–0.07 in a vacuum of 10–50 Pa and in dry nitrogen. The shearing ability of the interfacial film depends strongly on the nature of the atmosphere during friction, which affects the surface composition of the sliding counterfaces. A high vacuum is associated with ultralow friction and low wear. A poor vacuum and an inert atmosphere are associated with low friction and moderate wear. Ambient air is associated with relatively high friction and severe wear, coupled with the formation of roll-shaped debris of amorphous carbon containing iron oxide precipitates.
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Page 1. Substrate and process dependent losses in superconducting thin film resonators This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2008 Supercond. Sci. Technol. 21 075013 ...
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In this paper a novel field emission enhanced thermoelectric type cooler is proposed and theoretically analyzed. The thermoelectric cooler device proposed here uses an electric field modulated current to transport energy (ie, heat) from a... more
In this paper a novel field emission enhanced thermoelectric type cooler is proposed and theoretically analyzed. The thermoelectric cooler device proposed here uses an electric field modulated current to transport energy (ie, heat) from a cold source to a hot source via n-...
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Quantum computers are believed to have the potential to perform certain tasks much better than conventional computers. Recently, very promising results have been demonstrated with superconducting devices based on Josephson junctions. The... more
Quantum computers are believed to have the potential to perform certain tasks much better than conventional computers. Recently, very promising results have been demonstrated with superconducting devices based on Josephson junctions. The quality of the Josephson junctions plays an ...
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Various hydrogenated amorphous carbon films have been analyzed by 13C and 1H nuclear magnetic resonance (NMR) spectroscopies. The films have been deposited from acetylene or cyclohexane by dc plasma enhanced chemical vapor deposition, at... more
Various hydrogenated amorphous carbon films have been analyzed by 13C and 1H nuclear magnetic resonance (NMR) spectroscopies. The films have been deposited from acetylene or cyclohexane by dc plasma enhanced chemical vapor deposition, at various dc biases and gas pressures. The total hydrogen content has been measured by forward recoil elastic scattering (FRES). 13C NMR investigations have been performed in various configurations: high power decoupled to determine the sp2:sp3 carbon ratio, cross polarized at magic angle contact spinning with different contact times to provide information on carbon atoms directly bound to hydrogen, and with dipolar dephasing to study the quaternary carbon atoms. By performing the 13C and 1H NMR measurements on the same samples, it was possible to resolve for the first time the seven different forms of unprotonated and protonated CHx carbon, for both sp2(x=0,1,2) and sp3(x=0,1,2,3) carbon hybridizations, as well as the ratio between bound and unbound hydrogen. The results are discussed and compared with previously published FRES and Fourier transform infrared (FTIR) data. It is shown that NMR and FTIR combined with FRES do not agree systematically on the ratio of bound/unbound hydrogen.
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... Thermodynamic optimization of cross flow plate-fin heat exchanger using a particle swarm optimization algorithm. ... a SV National Institute of Technology, Surat, Gujarat State 395 007, India. ... Subscripts. a, b fluid a and b 1... more
... Thermodynamic optimization of cross flow plate-fin heat exchanger using a particle swarm optimization algorithm. ... a SV National Institute of Technology, Surat, Gujarat State 395 007, India. ... Subscripts. a, b fluid a and b 1 inlet 2 exit h hot c cold max maximum min minimum. ...
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AbstractOur Nb/AlO /Nb planarized process has been upgraded by adding extra dielectric and Nb wiring layers and the installation of an Inductively Coupled Plasma (ICP) etcher. Much higher quartz etch rates as well as reduced residue are... more
AbstractOur Nb/AlO /Nb planarized process has been upgraded by adding extra dielectric and Nb wiring layers and the installation of an Inductively Coupled Plasma (ICP) etcher. Much higher quartz etch rates as well as reduced residue are achieved with ICP etch. Etch ...
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Abstract-We describe the fabrication and properties of high critical current density (1,) Nb/AlO,/Nb Josephson junctions with deep-submicron dimensions. The junctions are fabricated using a planarized process in which all levels are... more
Abstract-We describe the fabrication and properties of high critical current density (1,) Nb/AlO,/Nb Josephson junctions with deep-submicron dimensions. The junctions are fabricated using a planarized process in which all levels are patterned us-ing a combination of ...
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The effect of 18-crown-6 ether on the decarboxylation rates of the sodium and potassium salts of 3-camphorcarboxylic acid 1 and of 1-carbomethoxy-1-carboxycyclohexane 2 was studied. For 2 the K-18C6 salt reacted ca. 104 times faster than... more
The effect of 18-crown-6 ether on the decarboxylation rates of the sodium and potassium salts of 3-camphorcarboxylic acid 1 and of 1-carbomethoxy-1-carboxycyclohexane 2 was studied. For 2 the K-18C6 salt reacted ca. 104 times faster than the parent acid. This ...
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Certolizumab pegol is a pegylated humanized Fab' fragment of an anti-tumor necrosis factor-alpha (TNFalpha) monoclonal antibody, which binds with high affinity to both membrane-bound and soluble TNFalpha and demonstrates high... more
Certolizumab pegol is a pegylated humanized Fab' fragment of an anti-tumor necrosis factor-alpha (TNFalpha) monoclonal antibody, which binds with high affinity to both membrane-bound and soluble TNFalpha and demonstrates high neutralizing potency for these factors. The elimination half-life of certolizumab in humans has been extended to approximate/= 2 weeks through pegylation, allowing subcutaneous administration of this agent once every 4 weeks. Subcutaneous certolizumab pegol 400mg once every 4 weeks (with an additional 400mg dose at week 2) was effective as induction and maintenance therapy in patients with moderate to severe Crohn's disease in whom baseline serum C-reactive protein levels were >/=10 mg/L, according to data from two well designed, randomized phase III trials. Certolizumab pegol was, in general, well tolerated, and adverse events associated with the drug were of a mild to moderate nature; no instances of lupus were reported in any of the trials.
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We present experimental evidence for a coherent superposition of macroscopically distinct flux states in an rf-SQUID. When the external flux Φx applied to the SQUID is near 1/2 of a flux quantum Φ0, the SQUID has two nearly degenerate... more
We present experimental evidence for a coherent superposition of macroscopically distinct flux states in an rf-SQUID. When the external flux Φx applied to the SQUID is near 1/2 of a flux quantum Φ0, the SQUID has two nearly degenerate configurations: the zero-and one-fluxoid ...
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By applying both low-frequency wavelength modulation and high-frequency phase modulation to a laser diode, we develop a sensitive, high-bandwidth chemical diagnostic tool that is applicable to a variety of gas-phase processing... more
By applying both low-frequency wavelength modulation and high-frequency phase modulation to a laser diode, we develop a sensitive, high-bandwidth chemical diagnostic tool that is applicable to a variety of gas-phase processing environments. Specific chemical species are identified and monitored through their infrared absorption spectra, and the modulation methods allow for sensitive detection that is free of window and other reflection-driven interference fringes. Absorbance limits of 5.3 x 10(-8) and 1.9 x 10(-7) are obtained for an AlGaAs diode laser and a lead-salt diode laser, respectively. We discuss applications to plasma etching and chemical vapor deposition.
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Devarajan Balaraman, Jinwoo Choi, Vijay Patel, P. Markondeya Raj, Isaac Robin Abothu, Swapan Bhattacharya, Lixi Wan, Madhavan Swaminathan and Rao Tummala Packaging Research Center Georgia Institute of Technology Atlanta, GA 30332-0560... more
Devarajan Balaraman, Jinwoo Choi, Vijay Patel, P. Markondeya Raj, Isaac Robin Abothu, Swapan Bhattacharya, Lixi Wan, Madhavan Swaminathan and Rao Tummala Packaging Research Center Georgia Institute of Technology Atlanta, GA 30332-0560 Phone: 404 894 2652 Fax: 404 ...
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We report measurements using pulsed microwaves to investigate the decoherence mechanisms in a large area Nb based flux qubit. Our qubit uses an rf-SQUID in a gradiometer configuration and has independent, in situ, controls for the... more
We report measurements using pulsed microwaves to investigate the decoherence mechanisms in a large area Nb based flux qubit. Our qubit uses an rf-SQUID in a gradiometer configuration and has independent, in situ, controls for the relative positions of levels in different fluxoid wells and the barrier height between the wells. We present measurements of decoherence times from coherent oscillations
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We report measurements of coherence times of an rf SQUID qubit using pulsed microwaves and rapid flux pulses. The modified rf SQUID has independent, in situ, controls for the relative positions of levels in different fluxoid wells and the... more
We report measurements of coherence times of an rf SQUID qubit using pulsed microwaves and rapid flux pulses. The modified rf SQUID has independent, in situ, controls for the relative positions of levels in different fluxoid wells and the barrier height between the wells. The decay of coherent oscillations is dominated by the lifetime of the excited state and low
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We report studies of macroscopic resonant tunneling (MRT) between fluxoid states in an rf-SQUID qubit as function of temperature. The measured tunneling rates as a function of flux bias exhibit evidence of energy level quantization up to... more
We report studies of macroscopic resonant tunneling (MRT) between fluxoid states in an rf-SQUID qubit as function of temperature. The measured tunneling rates as a function of flux bias exhibit evidence of energy level quantization up to a temperature (900 mK) well above the crossover temperature (TC) between the quantum and the thermal regime. The data agree with the level
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We are exploring conductance bistability (memory) effects in junctions based on metal oxides, in the context of their possible applications in hybrid CMOS/nanoelectronic (e.g., CMOL [1]) circuits. So far, we have investigated CuOx, NbOx... more
We are exploring conductance bistability (memory) effects in junctions based on metal oxides, in the context of their possible applications in hybrid CMOS/nanoelectronic (e.g., CMOL [1]) circuits. So far, we have investigated CuOx, NbOx and TiOx formed by thermal and plasma oxidation, with or without rapid thermal post-annealing (at 200 to 800^oC for 30 to 300 seconds). Conductance switching effects