Silicon sensors have about ten times improved radiationhardness around 130 K temperature, compared with the state-of-art sensors close to room temperature. This is based on the Lazarus effect studied by the RD39 Collaboration of CERN. Other benefits of low temperatures will also be discussed. We shall describe the conceptual design of low-mass detector modules cooled using two-phase flow of argon in miniature cooling pipes integrated in the module structure between the sensors and the readout hybrid circuit. The main engineering features of the cooling system and mechanical support structures are discussed, as well as the benefits arising from the operation of the tracker under cryogenic vacuum. 4 Refs.
We report on the design, fabrication and testing of two superconducting passive microwave components, a quadrature hybrid and a 20 dB directional coupler. These components are designed to be integrated with superconducting qubits or Josephson parametric amplifiers and used in quantum information processing applications. For the coupler, we measure return loss and isolation > 20 dB, and insertion loss 20 dB and insertion loss < 0.3 dB in a 10% band around 6.5 GHz. These values are within the design specifications of our application; however, we find a 7% difference between the designed and measured center frequency for the hybrid.
The controlled growth of nanowires (NWs) with dimensions comparable to the Fermi wavelengths of the charge carriers allows fundamental investigations of quantum confinement phenomena. Here, we present studies of proximity-induced superconductivity in undoped Ge/Si core/shell NW heterostructures contacted by superconducting leads. By using a top gate electrode to modulate the carrier density in the NW, the critical supercurrent can be tuned from zero to greater than 100 nA. Furthermore, discrete sub-bands form in the NW due to confinement in the radial direction, which results in stepwise increases in the critical current as a function of gate voltage. Transport measurements on these superconductor-NW-superconductor devices reveal high-order (n = 25) resonant multiple Andreev reflections, indicating that the NW channel is smooth and the charge transport is highly coherent. The ability to create and control coherent ...
The salient features of the near-infrared free-electron laser (FEL) that is under construction at the new Darmstadt superconducting 130-MeV electron accelerator are discussed. Special attention is given to the layout and the parameters of the accelerator, the layout of the planned FEL experiment, the characteristics of the electron gun, the subharmonic chopper-buncher system, and the hybrid undulator system of the Darmstadt FEL. A comparison of the planned Darmstadt FEL with conventional lasers, with respect to the pulse and wavelength region, is presented. 15 refs.
Microprocessor based ''smart'' pressure, level, and flow transmitters were tested to determine the radiationhardness of this class of electronic instrumentation for use in reactor building applications. Commercial grade Complementary Metal Oxide Semiconductor (CMOS) integrated circuits used in these transmitters were found to fail at total gamma dose levels between 2500 and 10,000 rad. This results in an unacceptably short lifetime in many reactor building radiation environments. Radiation hardened integrated circuits can, in general, provide satisfactory service life for normal reactor operations when not restricted to the extremely low power budget imposed by standard 4--20 mA two-wire instrument loops. The design of these circuits will require attention to vendor radiationhardness specifications, dose rates, process control with respect to radiation ...
A study of the influence of the concentration of secondary addition, high concentrations of primary dopant, diffusion enhancer and stabilizer on radiationhardness is presented. It is concluded that the diffusion enhancing technique is the most powerful method for improving radiationhardness. A new polystyrene scintillator which contains 2% pT, 0.02% POPOP, 20% diffusion enhancer and 0.02% stabilizer gave 91% of initial light output immediately after 3 Mrad irradiation in air. Data are presented that show that scintillator prepared from commercial polymer is more radiation-hard and has greater light output than scintillator prepared from monomer. It is assumed that this difference is due to different molecular weight distributions. Some protocols for acceleration of aging (yellowing and crazing) are presented. It is shown that one of the main reasons for aging of plastic ...
We report on measurements of radiationhardness of the plastic scintillating fiber SCSF-81. Fibers were irradiated with "6"0Co #gamma#-rays and fast neutrons up to 105 Gy and up to 5 x 1013 n/cm"2, respectively. Deterioration of the attenuation length of the scintillating fiber was studied. Some significant deterioration was observed at the integrated dose of about 1 x 103 Gy and at the integrated neutron flux (neutron fluence) of about 1 x 1012 n/cm"2 for #gamma#-ray and neutron irradiation, respectively. (author).
Total-dose irradiation seriously damages MOS devices and their circuit performance. Threshold voltage shifts, transconductance degradation and increase in off-state leakage current are generally observed for irradiated devices. These instabilities are essentially due to positive and/or negative charge trapping in SiO_2 and interface trap generation at the SiO_2/Si interface. Radiation hardening of CMOS VLSIs is to eliminate these trapping effects, and for this purpose, special considerations for fabrication processes and layout design are necessary. In this paper, basic mechanisms for radiation-induced charge trapping and related effects on MOS devices are reviewed. Also discussed are radiation-hardening technologies from both fabrication-process and layout-design viewpoints. Using these technologies, 1 #mu#m radiation-hard CMOS gate arrays have been successfully developed. Experimental data taken for 2k-gate test chips indicate that radiation ...
TNF-doped Mylar is a new radiation-hard dielectric that has recently been qualified as a viable substitute for Mylar in capacitors. The advantage of TNF-doped Mylar is that it satisfies both the nuclear safety and radiationhardness requirements of weapons. Mylar is not radiation-hard. Aging and compatibility studies were carried out to insure that (1) TNF does not diffuse from the film during fabrication of the capacitor or during storage; and (2) there are no compatibility problems with aluminum foil (the conductor) or Fluorinert (the secondary dielectric). Losses of TNF were barely detectable during the vacuum bakes used in fabricating capacitors or during accelerated aging tests carried out below T{sub g} (70C) over a two year period in air. In other accelerated tests, no compatibility problems were detected with aluminum or Fluorinert. TNF-doped Mylar is now being used in the MC-4109 capacitor that ...
The X-ray storage phosphor CsBr:Eu2+ in form of needle image plates is believed to be a promising alternative to the granular BaFBr:Eu2+ with regard to PSL yield and spatial resolution. Unfortunately, CsBr:Eu2+ exhibits poor radiationhardness, which is caused by a migration of europium ions initiated by naturally existing defect centers like (Eu2+-VCs)-centers and X-ray generated MEu-centers. It will be shown that the formation of (Eu2+-O2?)-dipoles at the expense of (Eu2+-VCs)-dipoles, incorporated by thermal annealing in O2-containing and humid atmosphere, does not improve the radiation stability. There is, however, a strong improvement in the radiationhardness by codoping of CsBr:Eu2+ with lithium ions, which is accompanied by a complete suppression of the previously observed MEu-cent...
The influence of additionally injected short-wavelength photobleaching light on the radiationhardness of Ge-doped graded index fibers working at 1,300 nm wavelength is investigated. Predictions are complicated by the fact that more efficient shortwave bleaching light experiences higher radiation-induced loss. Promising results are found for low fiber temperatures (approx-lt -50 C) and bleaching light of about 835 nm wavelength.
MPFDs are a new class of detectors that utilize properties from existing radiation detector designs. A majority of these characteristics come from fission chamber designs. These include radiationhardness, gamma-ray background insensitivity, and large signal output.
The influence of RTA (Rapid Thermal Anneal) treatment on MOS radiationhardness is demonstrated and compared with classical furnace treatment. In the case of the RTA, the oxide trapped charge is found to depend on: (i) the anneal temperature as expected, data are in good agreement with a recently developed model of oxygen out-diffusion; (ii) the location across the wafer with a radial dependence, results could be related to stress induced by thermal gradient.
A generic reactor model is used to examine the economic viability of electricity generation by magnetic fusion. The simple model uses components which are representative of those used in previous reactor studies of deuterium-tritium burning tokamaks, stellarators, bumpy tori, reverse field pinches and tandem mirrors. Conservative costing assumptions are made. The generic reactor is not a tokamak but rather it is intended to emphasize what is common to all magnetic fusion reactors. The reactor uses a superconducting toroidal coil set to produce the dominant magnetic field. To this extent it is a less good approximation to systems, such as the reversed field pinch in which the main field is produced by a plasma current. The main output of the study is the cost of electricity as a function of the weight and size of the fusion core - blanket, shield, structure and coils. The model shows that a 1200 MW/sub e/ power plant with a fusion core weight of about 10,000 tonnes ...
This proceedings volume comprises 17 papers on the following subjects: Methane hydrates, compounds of gas and water; Compressed air stroage gas turbine power plants / Scheduled application for load levelling between varying wind power production and power demand; Modern pumped storage power stations in the GW range - the PSW Goldisthal example; Lead batteries - new developments and future applications; Alkaline battery systems for hybrid electric road vehicles; Lighium systems and their applications; Zinc/air cells; Hydrogen storage - metal hydride storage, compressed gas storage, LNG storage; Carbon nanofibres for hydrogen storage; Double-layer condensers - technology, cost, perslpectives; Supercondensers in motor vehicles; Superconducting magnetic energy stores; Flywheel storage - status report; Decentralized energy storage in the European integrated supply grid - the EU project DISPOWER; Intercontinental integration of power supply - ...
Partial Contents: Ternary Compounds; Granular Superconductors; Superconductivity in (SN)x and its Halogen Derivative (SNBr0.4)x; Studies of cuCl at Elevated Pressures; Superconducting Properties of Hydride Systems; Thin Film Superconducting Materials Research; Synthesis of Superconducting Nb3Si using High Pressures; Synthesis of Unstable A-15 Compounds by Epitaxial Recrystallization of Ion Implanted Layers; and Sputtering of Nb3Si.
This report discusses the following topics on superconductivity: nonlinearities in hard superconductors such as surface impedance of a type II superconductimg half space and harmonic generation and intermodulation due to alternating transport currents; and nonlinearities in superconducting weak links such as harmonic generation by a long Josephson Junction in a superconducting slab.
In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10"2 #approx# 10"5 Gy/yr and 10"1"1 #approx# 10"1"4 n/cm"2/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiationhardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and "6"0Co #gamma#-rays in the region of the neutron fluence from 1 x 10"1"1 to 5 x 10"1"3 n/cm"2 and the integrated #gamma#-ray dose from 890 to 10"5 Gy, respectively. Deterioration of both intrinsic light yield and light transmittance of the ...
The theoretical hardness against total dose of the six-transistor SRAM cell is investigated in detail. An explicit analytical expression of the maximum tolerable threshold voltage shift is derived for two cross-coupled inverters. A numerical method is used to explore the hardness of the read and write operations. Both N- and P-channel access transistors designs are considered and their respective advantages are compared. The study points out that the radiationhardness mainly relies on the technology. Results obtained with the very robust Gate-All-Around process are finally presented.
The system study 'High Temperature Superconductivity (HTS) in power systems' lists the technical and economical advantages for power generation, transmission and distribution systems using components made of HTS material as seen in the light of current knowledge in the superconductivity area. This report lists the advantages of using high-temperature superconductivity in the power industry area and summarises the results obtained in various case studies on the subject.
The object of this report is to assemble information on and describe the situation for the development of hybrid vehicles and various alternatives within this field of development. In the report the description is concentrated mainly on the combination of combustion engine and electric battery, which is the most common combination in present day hybrid vehicles. In order to take a glimpse into the future even the combination of fuel cells and electric battery is described. The light duty electric hybrid vehicles which have been developed up to now are mainly parallel hybrids. If the development of hybrid systems takes place it will most certainly concern light duty vehicles which will come to be parallel hybrids equipped with an Otto or a diesel engine, depending on what the manufacturers wish to back. In the report the use of series hybrid ...
In this research, hybrid composite materials were prepared from combination of oil palm Empty fruit bunches (EFB) fibre and jute fibre as reinforcement, epoxy as polymer matrix. This study intended to investigate the effect of jute fiber hybridization and different layering pattern on the physical properties of oil palm EFB-Epoxy composites. Water absorption and thickness swelling test reveal that hybrid composite shows a moderate water absorption which is 11.20% for hybrid EFB/Jute/EFB composite and 6.08% for hybrid Jute/EFB/Jute composite. The thickness swelling and water absorption of the hybrid composites slightly increased as the layering pattern of hybrid composites changed. Hybrid composites are more water resistance and dimensional stable compare to the pure EFB composites. This is...
Procedures are described for the use of synthetic oligonucleotides for Southern blot experiments and gene bank screening, and the effect of various mismatches on the efficiency of hybridization is demonstrated. The following topics are discussed: sensitivity vs. specificity, hybridization of a 12-mer to the lambda endolysin gene; hybridization of oligonucleotide probes to the E. coli lac operator; hybridization of synthetic probes to the CYC1 gene of yeast; and cloning eucaryotic genes. (HLW)
The purpose of this project was to build a long-range, parallel hybrid gas/electric vehicle capable of driving beyond the communter capabilities of series hybrid vehicles. It was envisioned that since the gas engine would be able to independently propel t...
Quartz fiber calorimetry is a technique the signal generation mechanism of which is based on the Cherenkov effect. In this article we try to give a comprehensive overview of the subject. We start with a general introduction to calorimetry where the basic elements that characterize the development of electromagnetic and hadronic showers are discussed. Then we describe in detail the operation principle and the properties of calorimeters equipped with quartz fibers. The main advantages of this type of calorimeters are the radiationhardness, the fast response and the compact detector dimensions, features that derive from the quartz material and the specific mechanism of operation. A section is devoted to presenting the quartz fiber calorimeters that have been built or planned to in various experiments to operate as centrality detectors, trigger detectors, luminosity monitors or general purpose very forward calorimeters.
The RD50 collaboration has been exploring the development of radiationhard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1 MeV neutron equivalent (neq) cm-2. This is about an order of magnitude higher than the maximum dose for the most exposed silicon detectors in the current machine. RD50 investigates the radiation hardening of silicon sensors from many angles: improvement of the intrinsic tolerance of the substrate material, optimisation of the readout geometry and study of novel design of detectors. A review of some of the recent activities within RD50 is here presented.
The RD50 collaboration has been exploring the development of radiationhard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1MeV neutron equivalent (neq) cm-2. This is about an order of magnitude higher than the maximum dose for the most exposed silicon detectors in the current machine. RD50 investigates the radiation hardening of silicon sensors from many angles: improvement of the intrinsic tolerance of the substrate material, optimisation of the readout geometry and study of novel design of detectors. A review of some of the recent activities within RD50 is here presented.
The condition for obtaining a calorimetric response linear with energy for hadronic showers and an energy resolution that improves as the incident energy increases is the equalization of the electromagnetic (e) and the hadronic (#pi#) signal responses. This equalization is obtained by exploiting a local hardening effect realized through the insertion of low-Z thin plates between the high-Z absorbers and the active material in a hadronic calorimeter with silicon readout. This effect, which allows the reduction of the calorimeter response to the electromagnetic component of the incoming hadronic showers, has been investigated for different low-Z materials. The relevance of some aspects of this study to the radiationhardness of the calorimeters is also addressed. (orig.).
The introduction of tolerance to radiation (''radiation-hardness'') into large electronic systems is one of the major tasks to which this Handbook will be put. The practices recommended here for inculcating radiation-tolerance in equipment require advanced physical modeling techniques, precise engineering procedures, and firm assurance procedures. The degree to which these procedures should be used in an equipment project can be measured by the severity of the raw radiation environment, the desired reliability of the system, and the requirement of that project for radiation-sensitive technologies. The balance of device/circuit design versus shielding will depend on whether the radiation is highly penetrating -- as in isotope handling or military environments -- or readily attenuated, as in space. In this chapter the authors have attempted to summarize the essential features of the radiation hardening of large assemblies of equipment and how effective control of ...
A radiationhard low power, low voltage dynamic memory is obtained by the use of a dummy cell concept. Compared to conventional dummy cell concepts, this concept applies a fully sized dummy cell. By optimizing the dummy cell precharge voltage for 5 V and 3 V operation and the timing of the dummy word-line, the overall soft error rate (SER) of the chip is improved by 2 orders of magnitude. An additional improvement of 1 order of magnitude is possible for 3 V operation by adjusting substrate bias and cell plate voltage. The results are verified by an accelerated SER measurement with a radium 226 source and an additional field soft error study.
The variation in the superconducting properties of various binary alloys of transition metal-germanium systems was surveyed by studying sputter deposited samples prepared under various conditions. The primary interest has been to study the formation of the stoichiometric A-15 compounds T_3Ge.
Superconductivity in A-15 compounds is examined in terms of electron pairing induced by exchange of acoustic plasmons. The electronic band structure of Nb_3Sn, V_3Si, and similar materials favor transition temperatures of Tsub(c)approximately20 K. (Auth.).
Available data are presented which support the supposition that metals and alloys with a negative low-temperature Hall coefficient are apparently not superconducting. (author).
It is shown that calculation of the anomalous expectation values for the massless Gross-Neveu model in the Hartree-Fock approximation indicates the presence of an ordinary chiral phase transition if the coupling constant has the normal sign (g > 0) and of a different transition of the superconductivity type if g < 0.
This patent describes a method comprising applying a passivation layer of CaF{sub 2} to the surface of a superconductive ceramic oxide by evaporation. The CaF{sub 2} layer is effective to passivate the oxide surface without disrupting the superconductive properties.
The preparation by sputtering of artificial metallic superlattices is described, as are the results of x-ray structural determinations. Tunneling and resistivity measurements on these materials are reported.
... as time delay shifters for large-area phased arrays in military (MILSTAR) as well as commercial (Sky phone and other satellite communication) systems, ...
The dependence of Tsub(c) on composition and deformation is calculated and compared with the corresponding dependence for Tsub(m). It is shown that superconducting and structural properties of A-15 compounds can be described, at least qualitatively, by the quasi-one-dimensional model previously developed by the authors. The superconductivity mechanism is assumed to be analogous to the BCS theory. The upper critical field Hsub(c2) of the V_3Si or Nb_3Sn compounds is found to be much greater than that in V or Nb.
The correlation between superconductivity and structural transformation in the A-15 compounds are examined in a unified way on the basis of the Gor'kov three-dimensional model and the anisotropic pairing interaction. The temperature dependence of the elastic modulus, the strain order parameter and the energy gaps of superconductivity are obtained and compared with the experimental data. (auth.).
The possibility of fabricating a superconductive vertex detector is discussed on the basis of a preliminary experiment. The experiment has shown that an indium strip 15 mm long, 20 ..mu..m wide and 0.1 ..mu..m thick is changed from the superconductive state to the normal state when struck by a single 5.4 MeV alpha particle.
Improvements in critical current capacity for superconducting film structures are disclosed and include the use of a superconducting RE-BCO layer including a mixture of rare earth metals, e.g., yttrium and europium, where the ratio of yttrium to europium in the RE-BCO layer ranges from about 3 to 1 to from about 1.5 to 1.
This one-day TOPTEC session began with an overview of hybrid electric vehicle technology. Updates were given on alternative types of energy storage, APU control for low emissions, simulation programs, and industry and government activities. The keynote speech was about battery technology, a key element to the success of hybrids. The TOPEC concluded with a panel discussion on the mission of hybrid electric vehicles, with a perspective from industry and government experts from United States and Canada on their view of the role of this technology.
Hybrid vehicles have two power supplies as engine and electric motor which are used most efficiently corresponding to objects respectively to attain energy-saving and low pollution. In this paper, factors concerning the fuel economy of hybrid vehicles and potential thereof are examined, and the possibility of reducing fuel cost by half is described. As possible modes of highly efficient hybrid vehicles, series hybrid vehicles (SHEV) of conventional internal combustion engine, parallel hybrid vehicles using EV in combination, series-parallel hybrid vehicles (SPHV), series type fuel cell type vehicles, ceramic engine-turbo compound power generating SPHV as well as SHEV, and ceramics gas turbine engine power generating SHEV are mentioned. 10 refs., 14 figs.
Electron-beam codeposition of the elements to form certain high critical temperature superconducting materials, in particular A-15 compounds, has proven to be very useful in research directed at understanding and improving their superconducting properties. This work has used the close control of three or more evaporant sources to reproducibly make specimens that permit studies across selected regions of composition and phase space. The effect of composition and phase, together with the temperature and rate of deposition, on the growth morphology and superconducting properties has been studied. The superconducting properties measured include the critical temperature, ac loss, critical current density, and tunnel junction characteristics. The particular compounds studied include Nb_3Sn, Nb_3Ge, and V_3Si.
The magnetic properties of the superconductive materials HoBa/sub 2/Cu/sub 3/O/sub z/ and YBa/sub 2/Cu/sub 3/O/sub z/ have been measured and compared. Both had superconductive transition temperatures T/sub c/ in low magnetic fields near 90 K and exhibited nearly complete magnetic-flux exclusion. The susceptibility of the Ho-based materials followed a Curie-Weiss law both above and below T/sub c/. These results give clear experimental evidence for a nearly complete decoupling of the magnetic and superconductive layers, demonstrating that the superconductivity is highly anisotropic.
A solid layer artificial pollution test was carried out to study the pollution performance of a new type of hybrid station post insulator used in suspension and tensile high voltage transmission lines. The structure of the separated silicone rubber shed and porcelain core hybrid insulator was shown. The new insulator showed excellent pollution performance under both HVAC and HVDC conditions. It also exhibited excellent aging performance in artificial aging tests. The mechanical strength of the hybrid insulator was also better than normal composite insulators. Another advantage revealed was the fact that separated silicone rubber sheds and porcelain core hybrid post insulators are easier to manufacture than normal porcelain post insulators and other hybrid insulators. 5 refs., 6 tabs., 1 fig.
In 1992, the Society of Automotive Engineers (SAE) established a task force to develop a procedure for measuring electric energy consumption, all-electric range, fuel economy, and exhaust emissions for hybrid vehicles; the procedure will be submitted to regulatory agencies as representing the automotive industry`s recommendations. The draft procedure is currently being tested on hybrid vehicles. The University of Maryland`s parallel hybrid was tested in September 1994, and the University of California-Davis` parallel hybrid and the University of Illinois` series hybrid will be tested in November 1994 and January 1995, respectively. The procedure is being modified to incorporate any lessons learned, and the task force hopes to recommend the final procedure to the SAE by mid 1995.
Oxide superconducting thin films were irradiated with X-rays and ultra-violet (UV) light, and induced radiation effects on electrical and chemical properties were examined by transport measurement, X-ray diffraction analysis (XRD), diamagnetization measurement and X-ray photoemission spectroscopy (XPS). After irradiation for ErBa_2Cu_3O_x films with X-rays emitted from a Rh tube for 100 hours, superconductivity was remarkably damaged, destroying the zero-resistance state. The UV-light irradiation for Bi_2Sr_2CaCu_2O_x films was performed in He gas of about 500 Pa with a low pressure mercury lamp. The superconductivity was gradually degraded with the UV irradiation time up to 70 minutes. In both cases, adequate oxygen-annealing treatments restored superconductivity. The X-ray photoemission spectra showed that the mean Cu valence of the films was decreased approximately from +2 to +1 by the irradiation. ...
Superconducting MgB{sub 2} samples were prepared by the sintering of a mixture of fine Mg (or Mg alloy) powder produced by gas-atomization and B powder. The single MgB{sub 2} phase with a superconducting onset temperature of 38 K was obtained by sintering at 1073 K for the pure Mg or AZ31 alloy powders. In the case of AZ31, the superconducting MgB{sub 2} was obtained by sintering at a low temperature of 873 K for 50 h although a long sintering time of 100 h is needed to obtain a single MgB{sub 2} phase for Mg powder. This indicates that the AZ31 alloy enhances a formation rate of superconducting MgB{sub 2} at the low temperature through the formation of the partial melting phase. Thus, the gas-atomized fine Mg or AZ31 alloy powders are useful for preparation of a superconducting MgB{sub 2} and in particular AZ31 alloy is effective for the low temperature fabrication of MgB{sub 2}. ...
Superconducting magnetic and inertial energy pulsed power systems are being developed for future theta-pinch, Tokamak, and laser fusion applications. The short term requirements for these applications are discussed along with present day accomplishments. Areas requiring a research and development effort are examined in detail. Subjects discussed include stresses, energy loss factors, conductor metallurgy, cryogenic requirements, and electrical limitations of superconducting magnetic storage systems; costs, applications, and present technology of homopolar systems; and switching problems associated with both systems.
Raman scattering measurements of the Esub(g) and Tsub(2g) optical phonons in V"3Si, Nb"3Sn, V"3Ge, Cr"3Si, V"3Pt, and Nb"3Pt are presented and discussed in terms of interaction with interband electronic excitations. Data on superconducting Nb"3Sn is presented and modifications to the phonon spectral function and the spectrum of Raman active interband electronic excitations in the superconducting state are discussed. (orig.).
The mission of the Midwest Superconductivity Consortium, MISCON, is to advance the science and understanding of high {Tc} superconductivity. During the past year, 27 projects produced over 123 talks and 139 publications. Group activities and interactions involved 2 MISCON group meetings (held in August and January); with the second MISCON Workshop held in August; 13 external speakers; 79 collaborations (with universities, industry, Federal laboratories, and foreign research centers); and 48 exchanges of samples and/or measurements. Research achievements this past year focused on understanding the effects of processing phenomena on structure-property interrelationships and the fundamental nature of transport properties in high-temperature superconductors.
An apparatus is provided for rapidly restarting the flow of coolant through the cold electromagnetic shield of a superconducting rotor following a thermal transient episode. A vortex diode inhibits coolant flow in the undesirable reverse direction and encourages the reestablishment of a normal thermosyphon cooling loop flow quickly following the termination of a thermal transient such as that caused by transmission line faults. The present invention requires no moving parts and may therefore be permanently sealed in the superconducting rotor without risk of costly repair efforts caused by components failure.
Flywheels have the possibility of providing high turnaround efficiency and high specific power output. These characteristics are very important for the successful manufacture of parallel and series hybrid vehicles, which have the potential for providing h...
BackgroundGenetic interactions within hybrids influence their overall fitness. Understanding the details of these interactions can improve our understanding of speciation. One experimental...Full Text Available
To examine the association of human papillomavirus (HPV) infection with anal squamous cell carcinoma, the authors applied the highly sensitive polymerase chain reaction (PCR) and in situ hybridization...Full Text Available
Forest research on fast growing Eucalyptus hybrids in the Congo, using coppice shoots for propagation, is described. The hybrids can grow 20 ft in 15 months and it is suggested that the application of such methods in Britain may increase the growth rates of hardwoods such as oak or walnut.
Potential uses of foliage and bark wastes of E. ('Mysore') hybrid in southern India for the production of cineole and oxalic acid respectively are discussed. Only certain strains are cineole-rich and these are being successfully propagated vegetatively at the authors' laboratory.
Synthetic complementary oligonucleotides are useful hybridization probes for the detection of mRNAs and genes encoding proteins for which only a partial amino acid sequence is known. Usually this involves...Full Text Available
The results of this research centered on the experimental studies of a single superconducting persistent current qubit, the implementation of type-II algorithms using these qubits, and the proposal for adiabatic quantum computing using these qubits. The m...
The magnetic ordering temperature of some rare-earth-based heavy-fermion compounds is strongly pressure dependent and can be completely suppressed at a critical pressure, p{sub c}, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy-fermion antiferromagnets CePd{sub 2}Si{sub 2} and CeIn{sub 3} in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of p{sub c}. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. (author)
The magnetic ordering temperature of some rare-earth-based heavy-fermion compounds is strongly pressure dependent and can be completely suppressed at a critical pressure, p_c, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy-fermion antiferromagnets CePd_2Si_2 and CeIn_3 in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of p_c. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. (author)
The Fe-based copper oxide Formula Not Shown exhibits superconductivity around 50K only when it is properly annealed in Formula Not Shown atmosphere and subsequently in Formula Not Shown atmosphere. In contract Formula Not Shown does not exhibit superconductivity even if it is annealed along the same process as Formula Not Shown . We have synthesized the polycrystalline samples of Formula Not Shown solid solution system Formula Not Shown to investigate the Nd substitution effects. DC magnetization measurements have shown that, the samples in a range of Formula Not Shown exhibit superconductivity and Formula Not Shown was reduced with increasing the Nd content. However, we could not observe the superconductivity for Formula Not Shown and 1. Rietveld refinement results revealed that due to th...
This paper reports that only a few years ago superconducting magnetic separation was viewed as the next major market for superconducting magnets. The first commercial units had been installed, worked flawlessly, and demonstrated real economic viability. The potential market was seen as quite large, and many people believed that superconducting magnetic separation would soon show the same rapid growth that MRI had demonstrated after its initial success. These hopes even prompted IGC, one of the top MRI magnet builders, to form a separate division devoted to magnetic separation. Despite the existence of Magstream, IGC has not been overly active in the market. As a technology that has applications from the clay on the Earth to the soil on the moon, superconducting magnetic separation has yet to become widely used.
In these lecture notes we derive a generic holographic string theory realization of a p-wave superconductor and superfluid. For this purpose we also review basic D-brane physics, gauge/gravity methods at finite temperature, key concepts of superconductivity and recent progress in distinct realizations of holographic superconductors and superfluids. Then we focus on a D3/D7-brane construction yielding a superconducting or superfluid vector-condensate. The corresponding gauge theory is 3+1-dimensional N=2 supersymmetric Yang-Mills theory with SU(N) color and SU(2) flavor symmetry. It shows a second order phase transition to a phase in which a U(1) subgroup of the SU(2) symmetry is spontaneously broken and typical superconductivity signatures emerge, such as a conductivity (pseudo-)gap and the Meissner-Ochsenfeld effect. Condensates of this nature are comparable to those recently found experimentally in p-wave superconductors ...
... Schioler (703) 306-1836 lschiole@nsf.gov This material is available primarily for archival purposes ... of superconducting materials. Colossal magnetoresistance materials are those in which the electrical ...
magnet research at several national laboratories through its Advanced Accelerator Technology Program. The HEP Conductor Development Program, a collaboration among national...
Ab initio lattice dynamics based on linear response method are performed for high pressure phase of yttrium to describe electron-phonon coupling and subsequent superconducting behavior. The critical temperature Tc in fcc-Y increases monotonically with pressure up to 9.25 K at 31 GPa, which is quantitatively in excellent agreement with two quasihydrostatic experiments and is qualitatively compatible with recent experiments. The excellent agreement with experiments gives us a better understanding of the effective pseudopotential ?* as well as spectral function ?2(?)F(?) in yttrium. These results demonstrate that there exists strong electron-phonon coupling in Y within the studied pressure regime, and for lower pressure electron correlation becomes stronger. Generally, it is found that superconductivity in yttrium under pressure can be described quantitatively within standard theory of phonon-mediated superconductivity.
... and Security..........................13 Materials Science ... hybrid system theory, Internet analysis, materials science, mixing, physiology, iterative control ...
This article deals with the need for control strategies and control systems in buildings with hybrid ventilation. In this respect, control strategies are methods of keeping certain parameters like temperature, air quality etc within specified limits. A control system is automatic and includes sensors, motors, dampers etc. The article also discusses consequences with respect to thermal comfort, air quality and energy use following selection of control parameters for controlling air masses.
This research report discusses the radiation hardening of a commercially available mobile robot, the REMOTEC ANDROS. This hardening effort is culminating in the availability of a megarad hardened mobile platform to access areas in nuclear facilities with extremely high levels of radiation (0.1 to 1 Mrad). These radiation levels may be encountered both during routine repair and monitoring activities and accident situations. The project has completed a phase-I U.S. Department of Energy Small Business Innovative Research contract and is now in a phase-II effort with completion scheduled in early 1995. The research involves the evaluation of the material and electrical components of an ANDROS robot to determine the anticipated radiationhardness of the current production version and evaluation of the components that must be replaced or modified to harden the system to higher radiation levels. The work being reported is based on an evaluation of the ...
The National Renewable Energy Laboratory (NREL) evaluated the performance of diesel, compressed natural gas (CNG), and hybrid electric (equipped with BAE Systems? HybriDrive propulsion system) transit buses at New York City Transit (NYCT). CNG, Gen I and Gen II hybrid electric propulsion systems were compared on fuel economy, maintenance and operating costs per mile, and reliability.
Experimental data in the Kondo lattice YbPd_2Si_2 is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).
Experimental data in the Kondo lattice YbPd{sub 2}Si{sub 2} is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).
The occurrence of hybrid incompatibilities forms an important stage during the evolution of reproductive isolation. In early stages of speciation, males and females often respond differently to hybridization. Haldane's rule states that the heterogametic sex suffers more from hybridization than the homogametic sex. Although haplodiploid reproduction (haploid males, diploid females) does not involve sex chromosomes, sex-specific incompatibilities are predicted to be prevalent in haplodiploid species. Here, we evaluate the effect of sex/ploidy level on hybrid incompatibilities and locate genomic regions that cause increased mortality rates in hybrid males of the haplodiploid wasps Nasonia vitripennis and Nasonia longicornis. Our data show that diploid F(1) hybrid females suffer less from hybridization than haploid F(2) ...
This paper looks at the various battery technologies available for use in solar assist plug-in hybrid electric tractors In this context, solar assist plug-in hybrid electric tractors are those that may be used in light-duty agricultural operations. To determine the most suitable battery, four common technologies are analyzed looking at the environmental life-cycle effects and costs.
Contents of this volume include: Influence of Battery Characteristics on Traction Drive Performance; Chassis Design for a Small Electric City Car; Thermal Comfort of Electric Vehicles; Power Quality Problems at Electric Vehicle`s Charging Station; The Development and Performance of the AMPhibian Hybrid Electric Vehicle; The Selection of Lead-Acid Batteries for Use in Hybrid Electric Vehicles; and more.
The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are unusually rapid.
A simple model is used to explain the decrease in superconducting critical temperature with damage observed for irradiated A-15 compounds. A truncated t-matrix approximation is used to describe the disorder along the one-dimensional transition metal chains. Three dimensionality is introduced by the inclusion of interaction between transition metal atoms on different chains. Numerical fits to experiment are discussed in the conclusion. (author).
Superconducting thin film particle detectors can be very attractive due to the low sensitivity to radiation damage. We describe the fabrication procedure and the characterization of Nb/Al bilayers as particle detectors. First steady and dynamical results are reported from tests of 5 MeV alpha-particle detection.
The defect-induced effect on superconducting transition temperature T_c of A-15 compounds is examined. T_c is found from the Eliashberg equations which take into account the defect-induced changes in the electron-phonon spectral function and electron density of states. The dependence of T_c on the defect type in the superconductor is obtained.
The experimental superconducting magnetic system of 0.5 MJ energy storage is described. The step variation of the winding inductance provides a control by the discharge current at the energy output on a high-ohmic load. The voltage on a load is 45 kV at the current 1100 A under the controllable discharge conditions. The energy transfer coefficient constitutes 0,76 under the maximum-to-minimal current ratio equal to 1.3. 7 refs., 3 figs., 2 tabs.
Structural instabilities are now being found in many high-temperature superconductors. Compounds with the A-15 (#beta#-W) structure comprise the most important group of these materials, and their properties have been extensively studied for over 15 years. A review is given of some of these results, particularly those relating to the elastic behavior. The empirical relation of the structural instability and the anharmonicity to the high superconducting transition temperature is discussed.
The concept of the minimum propagating zone (MPZ) is used to examine the causes of quenches in ISABELLE cosine theta superconducting dipole magnets. The size of disturbances large enough to exceed the MPZ and initiate quenches is estimated and compared with the size of disturbances which may be produced in the magnets. A suggestion for reducing the size of these disturbances through individual support of the coil block is outlined.
The peculiarities of pulsed laser melting and evaporation of the superconducting ceramics are analyzed by means of numerical simulation. The appearance of the overheated metastable states in solid and liquid phases is shown as a result of the phase front dynamics and volume nature of laser energy release. A method of dynamic adaptation for the multifront Stefan problem is proposed.
A brief article gives an update on the commercial exploitation of superconductivity by the American Superconductor Corporation. Potential applications include transmission and distribution, motors, magnetic storage systems, current limiters and transport. The company have produced a kilometre long, ''wrappable'' cable capable of carrying thousands of amps when operating at a temperature of below -140[sup o]C. (UK)
A quantitative description is presented of the non-linear current-voltage response in superconducting niobium cavities for accelerator application. It is based on a fit for a large sample of data from cavity tests of different kind. Trial functions for the surface resistance describing this non-linear relation are established by a least square data fit. Those trial functions yielding the best fit are quantitatively explained by basic physics.
This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.
In order to examine the state of technology of all areas of magnetic suspension and to review related recent developments in sensors and controls approaches, superconducting magnet technology, and design/implementation practices, a symposium was held. The proceedings are presented. The sessions covered the areas of bearings, sensors and controls, microgravity and vibration isolation, superconductivity, manufacturing applications, wind tunnel magnetic suspension systems, magnetically levitated trains (MAGLEV), space applications, and large gap magnetic suspension systems.
Experimentally it is found that at constant temperature the order-parameter relaxation time, tausub(..delta..), decreases with increasing power of the microwaves, coupled into a superconducting strip. If the same increase in critical current, that corresponds with a given power of the microwaves, is obtained by lowering the temperature, the decrease in tausub(..delta..) is smaller. This reflects the fact that quasiparticles are removed more efficiently from the gap edge by microwaves than by lowering the temperature in equilibrium. A modified time-dependent Ginzburg-Landau equation is shown to describe these results adequately.
The electron structure of the A-15 compounds is studied by accounting for the Hubbard energy as the highest energy parameter. The conditions for the Cooper instability origination are obtained. The superconducting transition temperature dependence on the degree of filling the d- and p-shells of the transition and nontransition elements is determined. The relationship between the transition temperature and the energy jumpover along the chains, which allows comparison with the experiment, is established. Qualitative explanation of the Mattias empiric rules is presented
The universal depression of the superconducting transition temperature T/sub c/ in disordered A-15 compounds is examined. Existing energy-band calculations are used to calculate the density of electron states, which is possibly enhanced by disorder in some cases such as Nb_3Ge. The dramatic drop in T/sub c/ in Nb_3Ge at a critical value of the resistivity is attributed to overdamping of acoustic plasmons which decreases the electron pairing interaction despite small changes in the density of states.
Radionuclide X-ray fluorescence analysis was used for the determination of Cu, Y and Ba in very thin high-temperature superconducting films. The precision of the method is better than 3% for about 1 #mu#m thick films. The atomic emission ICP spectrometry was used to testify results of XRF analysis. An acceptable agreement of both methods was obtained. (author) 4 refs.; 2 tabs.
Electron microscopic observations of neutron irradiated Nb_3Sn revealed the presence of highly disordered regions of size approximately 35 A in a much less disordered matrix. This observation is shown to provide a means of explaining quantitatively many superconducting properties of irradiated A-15 compounds. In particular Tsub(c) of the irradiated materials could be easily predicted using the mathematical formulations developed for the proximity effect. (Auth.).
We propose a novel scheme for scalable solid state quantum computing, where superconducting microwave transmission line resonators (cavities) are arranged in a two-dimensional grid on the surface of a chip, coupling to superconducting qubits (charge or flux) at the intersections. We analyze how tasks of quantum information processing can be implemented in such a topology, including efficient two-qubit gates between any two qubits on the grid and elements of fault-tolerant computation.
Because of the equivalence principle, a global measurement is necessary to distinguish gravity from acceleration of the reference frame. A gravity gradiometer is therefore an essential instrument needed for precision tests of gravity laws and for applications in gravity survey and inertial navigation. Superconductivity and SQUID (superconducting quantum interference device) technology can be used to obtain a gravity gradiometer with very high sensitivity and stability. A superconducting gravity gradiometer has been developed for a null test of the gravitational inverse-square law and space-borne geodesy. Here we present a complete theoretical model of this instrument. Starting from dynamical equations for the device, we derive transfer functions, a common mode rejection characteristic, and an error model of the superconducting instrument. Since a gradiometer must detect a very weak differential gravity ...
Superconducting Cu-rich composites containing the A-15 compounds V_3Si or V_3Ga were made by the ''Tsuei'' process (melting into ingots followed by cold working and heat treatment). Superconducting transition temperatures of the composites were measured. X-ray diffraction analyses were performed. Microstructures were studied using both the optical metallograph and the scanning electron microscope. For some composites containing V_3Ga, the critical current densities as functions of transverse magnetic field up to 60 kG, and as functions of temperature from 4.2 to 12"0K were measured. It was found that the Tsuei process does not work for the composites containing V_3Si, but works satisfactorily for V_3Ga; reasons are discussed. Relations between measured properties and various metallurgical factors such as alloy compositions, cross-section reduction ratios, and heat treatment are discussed. The mechanism for the observed ...
In an attempt to enhance the electrical and mechanical properties of the high temperature superconducting oxides, high T(sub c) composites were prepared composed of the 123 compounds and AgO. The presence of extra oxygen due to the decomposition of AgO at high temperature is found to stabilize the superconducting 123 phase. Ag is found to serve as clean flux for grain growth and precipitates as pinning center. Consequently, almost two orders of magnitude enhancement in critical current densities were also observed in these composites. In addition, these composites also show much improvement in workability and shape formation. On the other hand, proper oxygen treatment of Y5Ba6Cu11Oy was found to possibly stabilize superconducting phase with T(sub c) near 250 K. I-V, ac susceptibility, and electrical resistivity measurements indicate the existence of this ultra high T(sub c) phase in this compound. Detailed structure, ...
Two examples of heavy-fermion systems are presented : CePd{sub 2}Si{sub 2}, an antiferromagnet with a quantum critical point at P{sub C}=28 kbar and UGe{sub 2} an itinerant ferromagnet which transits in a paramagnetic phase above P{sub C}=16 kbar. In CePd{sub 2}Si{sub 2} the superconductivity domain is centered on P{sub C}. Special attention was given to the superconducting and magnetic anomalies at their superconducting and Neel temperatures. In UGe{sub 2} superconductivity appears in 9 kbar at a temperature T{sub S}, more than two orders of magnitude lower than the Curie temperature; furthermore, it occurs only on the magnetic border (P<P{sub C}). Another characteristic temperature T{sub X} is detected by resistivity; the zigzag uranium chain of the lattice may favor a supplementary nesting in the majority spin band.
The lasing of the first free-electron laser (FEL) in the world was successfully carried out in 1977, so the history of FELs as a light source is not so long. But FELs are now utilized for research in many scientific and engineering fields owing to such characteristics as tunability of the wavelength, and short pulse and high peak power, which is difficult utilizing a common light source. Research for industrial applications has also been carried out in some fields, such as life sciences, semiconductors, nano-scale measurement, and others. The task for the industrial use of FEL is the realization of high energy efficiency and high optical power. As a means of promoting realization, the combining of an FEL and superconducting linac is now under development in order to overcome the thermal limitations of normal-conducting linacs. Further, since tuning the wavelength is carried out by changing the magnetic density of the undulator, which is now induced by moving part ...
Specific {sup 32}P-labeled DNA probes were prepared and used to evaluate the distribution of tetracycline resistance determinants carried by gram-negative enteric bacteria isolated from pigs in 3 swine herds with different histories of antibiotic exposure. Plasmid DNA, ranging in size from 2.1 to 186 Kb, was observed in over 84% of 114 isolates studied. Two of 78 tetracycline resistant strains did not harbor plasmids. The DNA probes were isolated from plasmids pSL18, pRT29/Tn10, pBR322 and pSL106, respectively, and they represented class A, B, C and D tetracycline resistance determinants. Hybridization conditions using 0.5X SSPE at 65{degrees}C minimize cross-hybridization between the different class of tetracycline resistance genes. Cross-hybridization between class A and class C determinants could be distinguished by simultaneous comparison of the intensity of their hybridization signals. Plasmids ...
This paper is a result of a research with the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the deeper, more fundamental causes of accidents and incidents. There have been significant improvements in the sophistication of quantitative methods of safety and risk assessment, but the progress on techniques most suitable for organizational safety risk frameworks has been limited. The focus of this paper is on the choice of 'representational schemes' and 'techniques.' A methodology for selecting appropriate candidate techniques and their integration in the form of a 'hybrid' approach is proposed. Then an example is given through an integration of System Dynamics (SD), Bayesian Belief Network (BBN), Event Sequence Diagram (ESD), and Fault Tree (FT) in order to demonstrate the feasibility and value of hybrid ...
Hybrid density functionals, which replaces a fraction of a density functional theory exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of ?-Pu. The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrids functionals with HF exchange amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization or itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. Overall, the performance of the ...
Hybrid density functionals, which replace a fraction of density functional theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of ?-Pu. The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrid functionals with HF exchanges amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization or itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. Overall, the performance of ...
Hybrid density functionals, which replace a fraction of density functional theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to study the structural, magnetic, and electronic properties of #delta#-Pu. The fraction of exact Hartree-Fock exchange used were 25%, 40%, and 55%. Compared to the pure PBE functional, the lattice constants expanded with respect to the experimental value when the PBE-HF hybrid functionals were applied. For pure PBE and hybrid functionals with HF exchanges amounts of 25% and 40%, the ground state structure was anti-ferromagnetic, while for 55% HF contribution the ground state was non-magnetic. The 5f electrons tend to exhibit slight delocalization of itinerancy for the pure PBE functional and well-defined localization for the hybrid functionals, with the degree of 5f electron localization increasing with the amount of HF exchange. Overall, the performance ...
The difference of NH_4"+-N/NO_3"--N nutrition between hybrid and conventional rice varieties at the late growth stage was studied by using "1"5N-tracer technique. The results showed that the nitrate fertilizer utilization efficiency by the hybrid rice after anthesis was 7.8% higher than that by the ordinary rice variety, and the nitrate fertilizer recovery fraction by the former was 13.2% greater than that by the latter. The varietal difference in NO_3"--N uptake and utilization was almost twice as that in NH_4"+-N. It was also showed that "1"5N distribution in ear of the hybrid rice was about 20% greater than that of the conventional variety, but there were no obvious differences between NO_3"--N and NH_4"+-N. However, "1"5N distribution in the lower node leaves and root was found to be significant higher with NO_3"--N than that with NH_4"+-N in both rice varieties, particularly in the hybrid rice. ...
The isostructural uranium monopnictides and monochalcogenides have become prototype systems in actinide research with respect to their unusual magnetic properties. We have investigated the origins in the electronic structure of the variation in magnetic behavior as the degree of 5f-electron localization changes from localized to itinerant on going up the pnictogen or chalcogen column, thus decreasing the U-U separation. We have applied a synthesis of: (1) A phenomenological theory of orbitally driven magnetic ordering which includes both the hybridization-induced and the RKKY exchange interactions on an equal footing, and (2) Ab initio electronic structure calculations, based on the linear-muffin-tin-orbital method, allowing a first-principles evaluation of the parameters entering the model Hamiltonian. We have investigated systematically characteristic trends and changes of the 5f-state resonance width, the hybridization potential, and the ...
We have investigated the superconducting and metallurgical properties of the ternary compounds RPd_2Si_2 and RRh_2Si_2 with R = Y, La, and Lu. All RPd_2Si_2 compounds and LaRh_2Si_2 were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases can easily mask the intrinsic (stoichiometric ratio 1:2:2) intermetallic-compound properties. Two sample-preparation techniques, viz., single crystals and off-stoichiometry, were utilized to establish where bulk superconductivity occurs. The type-I behavior of these compounds is explained with an analogous model as is used for the heavy-fermion superconductors CeCu_2Si_2 and URu_2Si_2.
Motivated by the discovery of superconductivity in alkali and alkaline earth fullerides, this program was undertaken both to understand the nature of and expand the range of materials demonstrating superconductivity. The first approach involved attempts to modify the fullerene cage by incorporating heteroatoms in the structure and the preparation and photophysical properties of nitrogen and sulfur doped fullerenes were studied in detail. The second approach involved examining the stoichiometry and effect of preparative conditions on the behavior of alkali, alkaline earth, lanthanide and mixed ion fullerides. In particular, the authors have elaborated on a technique for making such salts using liquid ammonia or aliphatic amines as solvents. Thirdly, modeling studies were undertaken to predict the properties of heterohedral fullerines and metal - C60 complexes, and theoretical guidelines were developed for understanding the reactivity of the ...
The investigation of strongly sintered ''quasi molten'' CuS and CuSe chalcogenides shows that they exhibit a sharp diamagnetic transition and a resistivity drop around 40 K. The reminiscence of such high temperature superconductivity features, never observed to date for these phases, is strongly supported by two chemical characteristics: bidimensionality of the structure and mixed valency of copper. The absence of zero resistance suggests that the internal chemical pressure in the samples has a key role in the existence of superconductivity: the S-S or Se-Se interlayer distances are very sensitive to the pressure, so that the critical distance for the percolation can be reached in the core of the samples, but not at the vicinity of the surface, where relaxation may appear.
The feasibility of using of current-biased superconducting strips for radiation detection is investigated. Narrow Ta strips are exposed to 5.5 MeV [alpha]-particle radiation and the rise-time of the induced voltage pulses is measured as function of temperature and bias current. The rise-time of the voltage signal strongly depends on the site on the strip which is hit by the [alpha]-particle. In order to determine the spatial resolution of a superconducting strip detector, position-sensitive measurements were performed. The maximum lateral resolution estimated so far is 25[mu]m in a 7[mu]m wide, 340 nm thick and 0.6 mm long Ta-strip. (orig.)
The influence of 3d-transition metal impurities on the superconducting properties of the A-15 compounds V_3Si and V_3Ga have been investigated. In the case of V_3Si, the Fe impurities replacing V were found to have a local moment. A compensation effect was found in this case, resulting in a 20KOe increase in the upper critical field at dilute concentrations of Fe. It was demonstrated that long range order V_3Ga possessed higher transition temperature and upper critical field than found hitherto. Investigations on Nb_3Ge/sub 1-x/Ga/sub x/ films obtained by chemical vapor deposition has clearly shown the relation between the transition temperature and structural characteristics. The influence of generalized defects on the superconducting properties in A-15 type Nb_3X compounds has been discussed.
This paper addresses the stability aspects of several successful dc superconducting magnets such as large bubble chamber magnets, and magnets for the Mirror Fusion Test Facility and MHD Research Facility. Specifically, it will cover Argonne National Laboratory 12-Foot Bubble Chamber magnets, the 15-foot Bubble Chamber magnets at Fermi National Laboratory, the MFTF-B Magnet System at Lawrence Livermore National Laboratory, the U-25B Bypass MHD Magnet, and the CFFF Superconducting MHD magnet built by Argonne National Laboratory. All of these magnets are cooled in pool-boiling mode. Magnet design is briefly reviewed. Discussed in detail are the adopted stability critera, analyses of stability and disturbance, stability simulation, and the final results of magnet performance and the observed coil disturbances.
Even though the currently intensive research efforts on high- temperature superconducting materials have not yet converged on a well specified practical material, the indications are that such a material may be quite brittle, anisotropic, and may contain many flaws such as microcracks and voids at grain boundaries. Consequently, practical applications of high temperature superconducting materials will require a very careful strength analysis based on fracture mechanics considerations. Because of the high sensitivity of the strength of such materials to the presence of defects, methods of quantitative non-destructive evaluation may be expected to play an important role in strength determinations. This proposal is concerned with the use of ultrasonic methods to detect and characterize isolated cracks, clusters of microcracks and microcracks distributed throughout the material. Particular attention has been, and will continue to be devoted to ...
Development of useful high-critical-temperature (high-{Tc}) superconductors requires synthesis of superconducting compounds; fabrication of wires, tapes, and films from these compounds; production of composite structures that incorporate stabilizers or insulators; and design and testing of efficient components. This report describes technical progress of research and development efforts aimed at producing superconducting components based on the Y-Ba-Cu, Bi-Sr-Ca-Cu, Bi-Pb-Sr-Ca-Cu, and Tl-Ba-Ca-Cu oxides systems. Topics discussed are synthesis and heat treatment of high-{Tc} superconductors, formation of monolithic and composite wires and tapes, superconductor/metal connectors, characterization of structures and superconducting and mechanical properties, and fabrication and properties of thin films. Collaborations with industry and academia are also documented. 10 figs.
The generation and control of quantum states of light constitute fundamental tasks in cavity quantum electrodynamics (QED). The superconducting realization of cavity QED, circuit QED, enables on-chip microwave photonics, where superconducting qubits control and measure individual photon states. A long-standing issue in cavity QED is the coherent transfer of photons between two or more resonators. Here, we use circuit QED to implement a three-resonator architecture on a single chip, where the resonators are interconnected by two superconducting phase qubits. We use this circuit to shuffle one- and two-photon Fock states between the three resonators, and demonstrate qubit-mediated vacuum Rabi swaps between two resonators. This illustrates the potential for using multi-resonator circuits as photon quantum registries and for creating multipartite entanglement between delocalized bosonic modes.
The effect of high energy neutron (E greater than 1 MeV) irradiation at 60"0C on the superconducting critical temperature, T/sub c/, the upper critical field, H/sub c2/, the lattice parameter, a_0, and the degree of Long Range Order has been measured for Nb and V based A-15 superconducting compounds. Large reductions in T/sub c/"0 and H/sub c2/ are observed for fluences up to 5.0 x 10"1"9 n/cm"2. For Nb_3Al, a_0 increases and the degree of Long Range Order is significantly reduced as T/sub c/ is depressed. Results are discussed in terms of atomic ordering in the A-15 structure.
It has recently been shown that the superconducting properties of Nb-base A-15 compounds, A_3B, are severely degraded when exposed to high-energy (E>1 MeV) neutron irradiation at ambient reactor temperatures. In each case, superconducting transition temperatures, Tsub(c), and the Bragg Williams order parameters, S, were observed to decrease steadily with irradiations in excess of 10"1"8 nvt. During irradiation the A-15 structure is retained and subsequent isothermal annealing restores almost completely the compound's original Tsub(c) value. In this letter a correlation between B atom diameter and the recovery rates of Tsub(c) for the irradiated materials Nb_3Ge, Nb_3Ga, Nb_3Al and Nb_3Sn is reported. (Auth.).
The Large Hadron Collider (LHC) will be equipped with several thousands of superconducting corrector magnets. Among the largest ones are the superconducting trim quadrupoles (MQTL). These twin-aperture magnets with a total mass of up to 1700 kg have a nominal gradient of 129 T/m at 1.9 K and a magnetic length of 1.3 m. Sixty MQTL are required for the LHC, 36 operating at 1.9 K in and 24 operating at 4.5 K. The paper describes the design features, and reports the measured quench performance and magnetic field quality of the production magnets. The MQTL magnet production is shared between CERN and industry. This sharing is simplified due to the modular construction, common to all twin-aperture correctors.
A thermodynamic analysis of a hybrid geothermal heat pump system is carried out. Mass, energy, and exergy balances are applied to the system, which has a cooling tower as a heat rejection unit, and system performance is evaluated in terms of coefficient of performance and exergy efficiency. The heating coefficient of performance for the overall system is found to be 5.34, while the corresponding exergy efficiency is 63.4%. The effect of ambient temperature on the exergy destruction and exergy efficiency is investigated for the system components. The results indicate that the performance of hybrid geothermal heat pump systems is superior to air-source heat pumps.
Using Southern, dot-blot and 'in situ' hybridization, molecular and cytological localization of repetitive 'Lupinus lueteus' DNA sequence was shown. Under CsCl gradient centrifugation conditions CG-rich satellite fraction appeared. Dot-blot hybridization clearly indicated that 1070bp repetitive element being a member of previously described EcoRI fragments family appeared only in the main band. The use of that DNA fragment as an 'in situ' hybridization signal in the euchromatin area. (author). 26 refs, 3 figs.
Nanoparticles represent versatile building blocks in material science and nanotechnology. Thereby, the defined assembly of nanostructures (13 and 56 nm in diameter, respectively) is of significant importance. Short DNA sequences can be bound to the nanoparticle surface thus enabling highly specific DNA hybridization-driven events that direct the formation of nanoparticle constructs.In this paper, examples for the defined formation of gold nanoparticle constructs are demonstrated. In addition, gold-silver core-shell nanoparticles are introduced as further building blocks for the hybridization-controlled formation of nanoparticle constructs.
... Program: Quallion Matrix Design (small cells) - Investigate the feasibly of a hybrid battery matrix composed of small D-sized cells for use in HEVs ...
In this Letter, we demonstrate the application of time-resolved fluorescence anisotropy measurements to detect solution state hybridization of streptavidin conjugate (CdSe)ZnS quantum dots (QD). The study was performed on samples containing 10nM QD incubated with 800nM DNA. We show that the rotational correlation time of QD-DNA constructs increases significantly upon hybridization with values of 330ns (QD-ssDNA) and 1.3ms (QD-dsDNA), corresponding to a diameter of 14nm and 23nm respectively. The present study opens a new modality for hybridization detection using quantum dots.
The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their...Full Text Available
Running torque of bearings, temperature rise of the lubricating oil and power loss of the testing system were compared with hybrid ceramic bearings set HIP-Si{sub 3}N{sub 4} balls and AISI-M 50 steel ball bearings under the 2 million dN value ({phi}20 x 100,000 rpm). Over 1.4 dN value, hybrid ceramic bearings showed superior performance than M 50 steel ball bearings. If the proper oil filling condition is chosen, hybrid ceramic bearings reduce bearing power loss to about 55% of AISI-M 50 steel ball bearings at 2 million dN value. (author)
A 206-size hybrid (ceramic/steel) cylindrical roller bearing was tested in MIL-L-23699 C oil at several speeds and loads. Heat-generation data was collected and subsequently correlated with bearing-analysis software. Bearing-cage slip data was also collected at various oil-flow rates, oil temperatures, and with both MIL-L-7808 J and MIL-L-23699 C oils. The hybrid bearing was tested in MIL-L-23699 C oil for for 25 hours at 2220 N radial load and 1.08 MDN shaft speed. The hybrid bearing technology demonstrated in the report is applicable to the Integrated High Performance Turbine Engine Technology Initiative. 15 refs.
In this study, Nylon 66/Polyester (Ny 66/PET) hybrid cord design and production was investigated to obtain new cord with better performance than conventional cord. The factors affecting cord properties and cord production process were examined. Taguchi design of experiment method was implemented in order to minimize the required number of experiments. Different sets of 4 reference cords conventionally used in tyre industry were prepared and resorcinol-formaldehyde-latex (RFL) treated in order to make a comparison of performance. Mechanical and thermal properties of hybrid cords were measured and compared with the values of reference cords. It was found that the twist level of high modulus PET component in the hybrid cords should be the same or above of the nylon in order to obtain maximum ...
A novel pseudo-morphotactic transformation route was developed to synthesize polycrystalline ?-W2N nanoplates by thermally treating tungstate-based inorganic-organic hybrid nanobelts with a lamellar microstructure in an NH3 flow. The tungstate-based hybrid nanobelts were formed in a water-in-oil-microemulsion-like 'commercial H2WO4 powders/n-octylamine/heptane' reaction system. The as-obtained hybrid nanobelts were thermally treated in an NH3 atmosphere at 650-800 oC for 2 h to form cubic ?-W2N nanoplates. XRD, SEM, TEM, FT-IR and TG-DTA were used to characterize the precursors and their final products. The polycrystalline ?-W2N nanoplates derived from hybrid nanobelts, with side lengths of several hundred nanometers, consist of small nanocrystals with an average grain size of 3.2 nm. The formation of ?-W2N nanoplates involved two steps: decomposing tungstate-based hybrid nanobelts ...
A novel heteropolyanion-based ionic hybrid was prepared by combining the divalent ionic liquid (IL) cation of 1,1'-(butane-1,4-diyl)-bis(3-methylimidazolium) with the Keggin-structured V-containing heteropolyanion, and characterized by ^1H NMR, FT-IR, ESI-MS, XRD, SEM, TG, BET surface area, melting point, and elemental analysis. Its catalytic activity was evaluated in the hydroxylation of benzene with aqueous H2O2, including the testing of the influence of organic cations, catalytic reusability and optimization of reaction conditions. This hybrid is characterized to be semi-amorphous nanoparticles with a IL-like composition. The hybrid catalyst leads to the liquid-solid biphasic reaction system for hydroxylation of benzene with H2O2, presenting such advantages as high catalytic activity, c...
... asymmetric versions of two different methods of joining GRP composite sandwich panels 3with steel were obtained (see Figure 1.7), the idea being ...
Manganese dioxide (MnO2) was prepared using the ultrasonic method. Its electrochemical performance was evaluated as the cathode material for a high voltage hybrid capacitor. And the specific capacitance of the MnO2 electrode reached 240 F.g-1. The new hybrid capacitor was constructed, combining Al/Al2O3 as the anode and MnO2 as the cathode with electrolyte for the aluminum electrolytic capacitor to solve the problem of low working voltage of a supercapacitor unit. The results showed that the hybrid capacitor had a high energy density and the ability of quick charging and discharging according to the electrochemical performance test. The capacitance was 84.4 mF, and the volume and mass energy densities were greatly improved compared to those of the traditional aluminum electrolytic capacito...
To test the hypothesis that a maternally transmitted cytoplasmic microorganism is involved in male hybrid sterility found in H. subflexa (Guenee) X H. virescens (F.) hybrid and backcross progeny, we reared H. subflexa, hybrids and backcross progeny on larval diets containing high concentrations of tetracycline, penicillin G, chloramphenicol, ampicillin, gentamicin, rifampin, and 5-iodo-2'-deoxyuridine. The insects tolerated relatively high concentrations (from 120 mg/liter to 6 g/liter) of antibiotics in the larval diet and showed virtually no changes in larval or pupal developmental time, adult lifespan, or fertility. Hybrid and backcross males reared on such adulterated diets were as sterile as those reared on conventional diets.
... California where he is currently working on an AS in. Data Communication & Network Management as well as Microsoft. MCSE and Cisco CCNA certifications.
... end-to-end TCP connection from the hybrid terminal ... peculiar to self-similar stochastic processes, ... Queue First (MDQF) schemes are employed at the ...
This paper presents a hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit. The sketch of the hybrid solar desalination process is given. The solar vacuated tube collector is employed in the desalination system, multi-effect humidification dehumidification desalination (HDD) process is plotted according to pinch technology, and then the water rejected from multi-effect HDD process is reused to desalinate in a basin-type unit further. The gain output ratio (GOR) of this system will rise by 2?3 at least through reusing the rejected water. The research proves that the multi-effect HDD has much room to be improved. A hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit should be no...
... HAL and VAL limits with the specified PMD of 10-7, the GPS range-rate error must be monitored to assure that the inertial navigation error is not ...
Superconducting rf cavities are increasingly used in accelerators. Gradient is a parameter of particular importance for the ILC. Much progress in gradient has been made over the past decade, overcoming problems of multipacting, field emission, and breakdown triggered by surface impurities. However, the quenching limit of the surface magnetic field for niobium remains a hard limitation on cavity fields sustainable with this technology. Further exploration of materials and preparation may offer a path to surpassing the current limit. For this purpose, we have designed a resonant test cavity. One wall of the cavity is formed by a flat sample of superconducting material; the rest of the cavity is copper or niobium. The H field on the sample wall is 75% higher than on any other surface. Multipacting is avoided by use of a mode with no surface electric field. The cavity will be resonated through a coupling iris with high-power rf at ...
The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V{sub 3}Si, Nb{sub 3}Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).
The federating theme of superconductivity has given rise to a number of experimental studies of point defects in solids as different as transition metals (V, Nb, ...), A-15 compounds (V_3Si, Nb_3Ge, ...), or perovskite-like copper oxides. Some of these experiments are presented here. (orig.).
An important application of metal hydrides is as a moderator material in nuclear reactors. The fundamental properties of hydrides are illustrated and an impression given of the current research into hydrogen in transition metals. Phase diagrams, magnetic properties, temperature dependence of the diffusion coefficient, energy level schemes and superconductivity are considered. (C.F.).
The effect of high-energy neutron irradiation (E greater than 1 MeV) at ambient reactor temperatures on the superconducting properties of a variety of superconducting compounds is reported. The materials studied include the A-15 compounds Nb_3Sn, Nb_3Al, Nb_3Ga, Nb_3Ge and V_3Si, the C-15 Laves phase HfV_2, the ternary molybdenum sulfide Mo_3Pb/sub 0.5/S_4 and the layered dichalcogenide NbSe_2. The superconducting transition temperature has been measured for all of the above materials for neutron fluences up to 5 x 10"1"9 n/cm"2. The critical current for multifilamentary Nb_3Sn has also been determined for fields up to 16 T and fluences between 3 x 10"1"7 n/cm"2 and 1.1 x 10"1"9 n/cm"2.
A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found ...
Brittleness and poor low-temperature thermal conductivity of A-15 compounds remain the major obstacles preventing the effective use of these superconductors in large-scale engineering applications. In order to circumvent these difficulties, a new type of ductile superconducting filamentary alloy has been developed recently by a simple metallurgical process which consists of melting the constituent elements and subsequent cold working and appropriate heat treatment. These superconducting materials are essentially Cu-base alloys containing a few percent of A-15 phase such as Nb_3Sn or V_3Ga which is in the form of fine filaments embedded in the Cu matrix. The emphasis of this work is on the formation of the A-15 phase in the Cu-base alloys and its correlation with superconducting properties such as transition temperature and critical current density. The formation of Nb_3Sn, Nb_3Al, V_3Si, and V_3Ga will serve as examples to ...
Following a brief description of the SSC, the computing needs are discussed for both the accelerator design and the experimentation. The computing power required is considerably beyond that being used at present facilities, and parallel processing is expected to play an important role in supplying these needs.
Model construction of the laboratory scale superconducting fault current limiter circuit (SFCL) has been performed. The SFCL is fault current limiter and used as electric network security. It mainly consists of a copper coil, a superconducting ring and an iron core that are concentrically arranged. The SFCL circuit is essentially a transformer where the secondary windings are being replaced by the ring of YBa_2Cu_3O_7_-_x superconductor (HTS). The ring has critical transition temperature Tc = 92 K and critical current Ic = 3.61 A. Characterization of the SFCL circuit is simulated by ANSYS version 5.4 software. The SFCL circuit consists of load and transformer impedances. The results show that the inductions of magnet field flux in the iron core of primer windings and ring disappear to one other before fault state. It means that impedance of the transformer is zero. After the condition a superconductivity behavior of the ...
A survey of theoretical research on acoustic plasmons is given and prospects for the observation of these elusive modes are examined. Possible acoustic plasmon contributions to the transition temperatures of the superconducting A-15 compounds are considered. Directions for future experiments and theory are suggested.
The A-15 compounds are known to favor the occurrence of high temperature superconductivity (transition temperature T/sub c/ > 15K). The origin of superconductivity in these metals is a subject of much controversy and importance. A useful approach to this problem is to study comparatively the superconducting and normal-state properties of the A-15 superconductors and their amorphous counterparts. Efforts along these lines have yielded some insight into the mechanisms responsible for high temperature superconductivity. It is interesting to note that most high-T/sub c/ A-15 compounds contain one glass-forming element such as Ge, Si or Al and are thus conducive to the formation of a non-crystalline phase. The amorphous (or higher disordered) state of the A-15 compounds can be achieved, for example, by one of the following techniques: (1) sputtering or co-evaporation onto substrates held at relatively low ...
The effect of high energy neutron irradiation (E > 1 MeV) on the superconducting transition temperature, Tsub(c), of the A-15 compound Mo_3Os is reported. Tsub(c) was found to decrease with increasing neutron dose, but at a rate considerably less than observed in other A-15 compounds composed of non-transition metals. The results lend support to the idea that the effect of ordering on Tsub(c) is smaller for A-15 compounds composed only of transition metals than those composed of transition and non-transition metals. (author).
The behavior of the superconducting transition temperature T/sub c/ of single-crystal and polycrystalline V_3Si was investigated as a function of low-fluence neutron irradiation. It is found that the initial degradation of T/sub c/ is sample-dependent, some specimens showing no degradation in T/sub c/ up to a fluence of 2 x 10"1"8 n/cm"2. This and many other earlier observations on low-fluence behavior are explained in terms of a recently proposed model of radiation damage in A-15 compounds.
The study of the intrinsic behavior of high transition temperature copper-oxide superconductors (HTSC) has proven to be challenging because of the extreme sensitivity of their transport properties on material quality. These compounds are characterized by a high degree of structural and electrical anisotropy, and a very short superconductive coherence length of the same order as the size of the crystalline unit cell (~5-30 A). As a result, microscopic defects such as oxygen vacancies, cationic disorder, and the presence of minute impurities have a significant effect on electrical transport in these materials. Therefore, much effort has been expended in synthesizing sizable samples that are homogeneous, well characterized, and emenable to the study of the anisotropic properties of the HTSC. We have demonstrated that thin films of HTSC compounds such as rm YBa_2Cu_3O_{7 -delta}, which is a 92 K superconductor, can be synthesized easily by a technique known as pulsed ...
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high {Tc} superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high T_c superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high [Tc] superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
It is pointed out that a recently claimed result regarding the removal of sharp structure in the electronic density of states N(E) of A-15 superconducting compounds at T approximately equal to Tsub(c) was in fact, shown earlier by one of the present authors (M.N.M.). Merely the variation of N(E) with energy in the vicinity of the Fermi level in these materials cannot explain their anomalous normal state properties and high values of lambda and Tsub(c). Rather a non-varying N(E) accompanied by phonon softening is in better agreement with experiment.
It is pointed out that a recently claimed result regarding the removal of sharp structure in the electronic density of states N(E) of A-15 superconducting compounds at T approximately equal to Tsub(c) was in fact, shown earlier by one of the present authors (M.N.M.). Merely the variation of N(E) with energy in the vicinity of the Fermi level in these materials cannot explain their anomalous normal state properties and high values of lambda and Tsub(c). Rather a non-varying N(E) accompanied by phonon softening is in better agreement with experiment. (author).
We discuss how magnetic phenomena affect superconductivity in simple metals, transition metals and alloys thereof, and dilute Rare-Earth alloys. It is shown both qualitatively and quantitatively that superconductors are sensitive probes for studying itinerant spin excitations, local spin excitations associated with nearly magnetic impurities, the effect of the atomic environment on the stability of local magnetic moments, and the nature of the spin order in Rare-Earth alloys. Also, we discuss how magnetic impurities can be used to study the electronic configuration which is responsible for superconductivity in Laves-phase crystals like A-15 compounds and ..beta..-W crystals, for example.
High-T/sub c/ superconductivity is due to the action of two mechanisms: (1) plasmon mechanism, i.e., exchange of two-dimensional (2-D) plasmons and (2) strong electron--phonon coupling. The low dimensionality and the small value of the carrier concentration make the plasmon mechanism favorable. The small value of the coherence length leads to a unique opportunity to observe a multigap structure. The proximity effect can be used in order to increase T/sub c/ of A-15 compounds.
Characterization of high temperature superconducting film and bulk samples has been carried out using 2 MeV [alpha]-particle Rutherford backscattering, 2.4 MeV proton elastic scattering, 2.4 MeV proton-induced x-ray emission, 9 MeV proton induced [gamma]-ray emission and 100 MeV iodine elastic recoil detection analysis techniques. The objective was to compare different ion beam based techniques for: (i) compositional analysis; and (ii) consistency of the results obtained for samples prepared using similar preparation methodology. (author).
We study a quantum computing system using microwave photons in transmission line resonators on a superconducting chip as qubits. We show that linear optics and other controls necessary for quantum computing can be implemented by coupling to Josephson devices on the same chip. By taking advantage of the strong nonlinearities in Josephson junctions, photonic qubit interactions can be realized. We analyze the gate error rate to demonstrate that our scheme is realistic even for Josephson devices with limited decoherence times. As a conceptually innovative solution based on existing technologies, our scheme provides an integrated and scalable approach to the next key milestone for photonic qubit quantum computing.
This report summarizes current status of an R&D program to develop a focusing system for the front end of a superconducting RF linac. Superconducting solenoids will be used as focusing lenses in the low energy accelerating sections of the front end. The development of focusing lenses for the first accelerating section is in the production stage, and lens certification activities are in preparation at FNAL. The report contains information about the focusing lens design and performance, including solenoid, dipole corrector, and power leads, and about cryogenic system design and performance. It also describes the lens magnetic axis position measurement technique and discusses scope of an acceptance/certification process.
One of the most complicated tasks during the assembly of the Wendelstein W7-X is the installation of the superconductive coil system. The entire magnet system is enclosed between the Outer Vessel and the plasma vessel in high vacuum at 4 K. The coils are supported by a support structure, the Central Support Structure (CSS). The CSS carries all 70 coils, and it is designed as a closed ring made of 5 modules (10 half modules). The whole structure is supported by 10 Cryolegs which rest on the machine base. This paper describes the final design and manufacture of these Cryolegs.
In this paper, we review some of the work our group has done in the past few years to obtain the electron self-energy of high temperature superconductors by analysis of angle-resolved photoemission data. We focus on three examples which have revealed: (1) a d-wave superconducting gap, (2) a collective mode in the superconducting state, and (3) pairing correlations in the pseudogap phase. In each case, although a novel result is obtained which captures the essence of the data, the conventional physics used leads to an incomplete picture. This indicates that new physics needs to be developed to obtain a proper understanding of these materials.
The electromagnetic properties of a prototype gravitational wave detector, based on two coupled superconducting microwave cavities, were tested. The radio-frequency (rf) detection system was carefully analysed. With the use of piezoelectric crystals small harmonic displacements of the cavity walls were induced and the parametric conversion of the electromagnetic field inside the cavities explored. Experimental results of bandwidth and sensitivity of the parametric converter versus stored energy and voltage applied to the piezoelectric crystal are reported. A rf control loop, developed to stabilize phase changes on signal paths, gave a 125 dBc rejection of the drive mode on a time scale of 1 h.
The author shows in this paper an interesting relation between elementary and topological excitations in the antiferromagnetic and d-wave superconducting phases of the t-J model at two dimensions. The topological spin and charge excitations in one phase have the same dynamics as elementary excitations in the other phase, except the appearance of energy gaps. Moreover, the transition from one phase to another can be described as a quantum disordering transition associated with the topological excitations. Based on the above picture, a plausible phase diagram of t-J model is constructed.
Recently, a superconducting cryo-electron microscope in which specimens are cooled to the liquid helium temperature (4.2 K) has been developed. The main components and functional features of this new microscope are reported together with application data on polyethylene, poly (4-methyl-1-pentene), valonia cellulose, rock salt, ice crystallites and ceramic superconductor. The resistance to electron radiation damage, of beam-sensitive specimens including polymers has been increased more than ten times. Thus, the microscope has made it possible to take high resolution images and to analyze the crystal-structure of micro-areas. (orig.).
The study is concerned with the combined effect of high pressure and shear strain on the properties of the A-15 intermetallics Nb3Sn and Nb3Al0.75Ge0.25. The properties discussed are the superconducting transition temperature, the width and intensity of the X-ray diffraction lines, and the width and shape of the Mossbauer absorption lines. It is shown that the combined effect of high pressure and shear strain leads to an intense generation of defects in polycrystalline specimens; the size of the ordered regions does not exceed 300 A even under the least severe conditions. 5 references.
In one of the first uses of high Tc superconductors in an end-use product, Lake Shore Cryotronics and a Swiss lab have developed a liquid nitrogen level sensor using a high Tc thin film. The probe is manufactured using a seamless stainless steel tube with an yttrium-based zirconium oxide flame-sprayed on the tube. A plasma-sprayed superconductor compound is deposited on top of that. The probe is coated with a sealant that protects the superconducting film from the atmosphere. This manufacturing method has yielded an extremely durable product. Unaffected by ice formation and related mechanical problems, the superconducting level sensor can be kept in the dewar for long periods of time.
Cycling parameters (reversible specific capacity, first-cycle coulombic efficiency, accumulated irreversible capacity, and reversible capacity retention) of hybrid electrodes based on mechanical mixtures of a silicon nanopowder with KS6 and MAG-20 synthetic graphites and binders of varied nature were subjected to an integrated analysis in comparison with graphite electrodes.
This comprehensive, critical review summarizes the use of nanoparticles in enhanced and amplified chemiluminescence detection, illustrated by different reaction strategies, electrogenerated chemiluminescence sensors, immunoassay or hybridization labels and electrogenerated chemiluminescence immunoassay or hybridization sensors. We discuss the analytical applications on the basis of validity, range and sensitivity, and draw some useful conclusions about the most sensitive approach in each type of application.
Commonly used EV battery tests are not very suitable for testing hybrid vehicle batteries, which may be primarily intended to supply vehicle acceleration power. The capacity of hybrid vehicle batteries will be relatively small, they will typically operate over a restricted range of states-of-charge, and they may seldom if ever be fully recharged. Further, hybrid propulsion system designs will commonly impose a higher regeneration content than is typical for electric vehicles. New test methods have been developed for use in characterizing battery performance and life for hybrid vehicle use. The procedures described in this paper were developed from the requirements of the government-industry cooperative Partnership for A New Generation of Vehicles (PNGV) program; however, they are expected to have broad application to the testing of energy storage devices for hybrid vehicles. The ...
The fabrication of a Prototype 275/sup 0/C Geothermal Temperature Tool is reviewed. This tool fabrication uses hybrid circuits that were developed at Sandia National Laboratories and are now being built at Teledyne Philbrick. To achieve high-temperature operation, the standard military specification hybrid technology was modified in fabrication processes and materials.
The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment ...
The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment ...
A new exhaust cleaning system is introduced, aiming to remarkably reduce NOx emission using a type of EGR method (hybrid EGR) of feeding back the exhaust from an exhaust cleaning ternary catalyst provided gasoline engine to the Diesel engine intake on one hand and, on the other hand, aiming to reduce even the emitted particulates using an exhaust supplying gasoline engine driven supercharger for an enhanced Diesel engine supercharging. The hybrid EGR system used here can uniformly reduce the emitted NOx under any load conditions and, as compared with the conventional type, is two to three times more effective, with the EGR rate kept constant. The exhaust concentration is approximately 10%. An sample of the hybrid EGR was simulated, and it was shown, as compared with the original non-supercharged Diesel engine, that the emitted NOx decreased to 1/3 or 1/4, that the exhaust concentration was approximately the same, and that ...
This paper describes potentials on fuel economy and NO{sub x} exhaust emissions of a series hybrid urban bus system equipped with a ceramic gas turbine engine (CGT). The simulating program developed in-house was used to analyze influences of several parameters of each main components of the hybrid vehicle system on the performance of the bus running on the modified bus driving cycle. The basic data used in this analysis for a CGT was derived from the results of 'the Automotive 100kW CGT Project' of Japan. A dynamic response of a CGT-Generator rotating system was very much improved by introducing of 'Assisting system' in which the generator was used as an acceleration-deceleration assisting device when much acceleration or deceleration was needed. This system would make a CGT operate along the optimum operating line (fuel minimum line) even under the unsteady driving conditions. This analysis showed that the ...
This paper presents the performance analysis on a hybrid air-conditioning system according to the hybrid building energy system of the green building demonstration project in Shanghai, in which a 150 m{sup 2} solar collector is used to power two 10 kW adsorption chillers, a vapor compression heat pump is used to cool air in the evaporating end while the condensing heating at about 80{sup o}C is fully used to regenerate a liquid desiccant dehumidification system. In the hybrid system, the sensible cooling to the air is treated mainly by solar adsorption cooling and vapor compression cooling, whereas the latent heat is treated by the liquid desiccant dehumidification system with regeneration from the condensing heat of the heat pump. The results show that the performance of this system is 44.5% higher than conventional vapor compression system at a latent load of 30% and this improving can be achieved by 73.8% at a 42% latent ...
In the advance of fuel cell electric vehicles (EV), hybrid electric vehicles (HEV) can contribute to reduced emissions and energy consumption of personal cars as a short term solution. Trade-offs reveal better emission control for series hybrid vehicles, while parallel hybrid vehicles with different drive trains may significantly reduce fuel consumption as well. At present, costs and marketing considerations favor parallel hybrid vehicles making use of small, high power batteries. With ultra high power density cells in development, exceeding 1 kW/kg, high power batteries can be provided by adapting a technology closely related to consumer cell production. Energy consumption and emissions may benefit from regenerative braking and smoothing of the internal combustion engine (ICE) response as well, with limited additional battery weight. High power supercapacitors may assist the achievement of this goal. ...
This project is a seven year plan starting from 1997, and is aiming at developing vehicles that use the clean energy instead of petroleum, consume 1/2 of the running energy and discharge 1/2 of the CO{sub 2} of the existing vehicles. The research and development are respectively conducted for every kind of vehicles. Namely, for cars, the developments focus on methanol improved fuel battery cars and ANG series hybrid vehicles carried with flywheel battery. For 2 ton loading trucks, they are CNG self-ignition ceramics engine, capacitor/battery in combination use, series hybrid vehicles in combination with discharge energy recovery technology, CNG rarefaction combustion engine, use of lithium ion battery, and series/parallel hybrid vehicles etc. And, LNG mirror cycle engine, capacitor carrying, series hybrid vehicle, dimethylether engine, flywheel battery or capacitor carrying series ...
Two overlapping cDNA clones encoding human DNA topoisomerase II were identified by two independent methods. In one, a human cDNA library in phage {lambda} was screened by hybridization with a mixed oligonucleotide probe encoding a stretch of seven amino acids found in yeast and Drosophila DNA topoisomerase II; in the other, a different human cDNA library in a {lambda}gt11 expression vector was screened for the expression of antigenic determinants that are recognized by rabbit antibodies specific to human DNA topoisomerase II. The entire coding sequences of the human DNA topoisomerase II gene were determined from these and several additional clones, identified through the use of the cloned human TOP2 gene sequences as probes. Hybridization between the cloned sequences and mRNA and genomic DNA indicates that the human enzyme is encoded by a single-copy gene. The location of the gene was mapped to chromosome 17q21-22 by in situ ...
In our evaluation we utilized the Asahi Mark-J NMR-CT system, with a resistive vertical quadrupolar electromagnet (0.1 Tesla) and a proton resonance frequency of 4.5 MHz. Our main imaging methods are the inversion-recovery or IR, saturation-recovery, or SR, and calculated T/sub 1/. Difference, or D images, constructed by subtracting the data of the IR signal from that of the SR signal, have also been obtained in some cases. The system allows averaging of raw data. Hybrid images were constructed from two or more images to obtain clear definition of areas of interest. By using the hybrid image, several tissues of different relaxation times can be shown in the same image. Application in our study of the newly developed hybrid image indicates its importance in the detection and diagnosis of lesion, especially the detection of the differentiation of an edematous lesion from a tumor, and also abnormal fluid collection such as the ...
Off-grid power generation is meant to supply remote or rural area, where grid connection is almost impossible in terms of cost and geography, such as island, aborigine's villages, and areas where nature preservation is concern. Harnessing an abundance renewable energy sources using versatile hybrid power systems can offer the best, least-cost alternative solution for extending modern energy services to remote and isolated communities. The conventional method for off-grid power generation is using diesel generator with a renewable energy (RE) technology utilizing solar photovoltaic, wind, biomass, biogas and/or mini/micro hydro. A hybrid technology is a combination of multiple source of energy; such as RE and diesel generator and may also include energy storage such as battery. In our design, the concept of solar hybrid system is a combination of solar with diesel genset and battery as an energy storage. The main objective ...
Electric and hybrid-electric vehicles are being developed and commercialized around the world at a rate never before seen. These efforts are driven by the prospect of vehicles with lower emissions and higher fuel efficiencies. The widespread adaptation of such vehicles promises a cleaner environment and a reduction in the rate of accumulation of greenhouse gases, Critical to the success of this technology is the use of electrochemical power sources such as batteries and fuel cells, which can convert chemical energy to electrical energy more efficiently and quietly than internal combustion engines. This overview will concentrate on the work being conducted in the US to develop advanced propulsion systems for the electric and hybrid vehicles, This work is spearheaded by the US Advanced Battery Consortium (USABC) for electric vehicles and the Partnership for a New Generation of Vehicle (PNGV) for hybrid-electric vehicles, both ...
Biomass is one of the main natural resources in Sweden. The present low-CO{sub 2} emission characteristics of the Swedish electricity production system (hydro and nuclear) can be retained only by expansion of biofuel applications for energy purposes. Domestic Swedish biomass resources are vast and renewable, but not infinite. They must be utilized as efficiently as possible, in order to make sure that they meet the conditions for sustainability in the future. Application of efficient power generation cycles at low costs is essential for meeting this challenge. This applies also to municipal solid waste incineration with energy extraction, which should be preferred to its dumping in landfills. Hybrid dual-fuel combined cycle units are a simple and affordable way to increase the electric efficiency of biofuel energy utilization, without big investments, uncertainties or loss of reliability arising from complicated technologies. Configurations of such power cycles are ...
YBa{sub 2}Cu{sub 3}O{sub x} superconducting ceramics containing various oxides were prepared, and their superconducting properties and degradation in moisture were discussed. The addition of Ag{sub 2}O greatly contributed to improve their properties, for example, in the specimen containing Ag{sub 2}O of 1-5wt%, a relative density was enhanced up to 95% of a theoretical density, and a critical current density was 2-3 times as large as that of non-added one. As the results of accelerated aging tests at 85{degree}C in the air of 100% relative humidity, in non-added specimens, the resistivity vs. temperature characteristics were strongly affected by moisture only for 30min, however, in Ag-added ones, no effects were detected even after 5h. A superconducting wire was made of an Ag pipe and superconducting powder containing Ag{sub 2}O of 5wt% by drawing and heating at 850{degree}C in air for 20h, and its ...
Building complex knowledge based applications requires encoding large amounts of domain knowledge. After acquiring knowledge from domain experts, much of the effort in building a knowledge base goes into verifying that the knowledge is encoded correctly. We consider the problem of verifying hybrid knowledge bases that contain both Horn rules and a terminology in a description logic. Our approach to the verification problem is based on showing a close relationship to the problem of query containment. Our first contribution, based on this relationship, is presenting a thorough analysis of the decidability and complexity of the verification problem, for knowledge bases containing recursive rules and the interpreted predicates =, {le}, < and {ne}. Second, we show that important new classes of constraints on correct inputs and outputs can be expressed in a hybrid setting, in which a description logic class hierarchy is also considered, and we ...
Diesel power technology has been utilized worldwide, especially in remote regions, because of its low initial capital cost. But it has negative effects on the surrounding environment and causes global warming. On the other hand, depleting oil and fuel resources has made it inevitable to seek alternative/renewable energy resources. In Iran, the cost of fuel is highly subsidized. If Iran removes the fuel subsidy, the cost of diesel fuel would increase and the photovoltaic (PV) or hybrid PV/diesel systems would become more attractive. Hybrid photovoltaic/diesel/battery (PV/diesel/bat) systems which use PV energy, combined with diesel generation power and battery bank storage are an excellent solution to decrease diesel generator costs, pollution, and electrification of remote rural areas. In ...
This report summarizes the work performed by Honeywell during the October 2001 to December 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The conceptual and demonstration system designs were proposed and analyzed, and these systems have been modeled in Aspen Plus. Work has also started on the assembly of dynamic component models and the development of the top-level controls requirements for the system. SOFC stacks have been fabricated and performance mapping initiated.
One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At the same time, it identifies both the mechanism of pore formation and a remedy for this problem. The experimental results indicate that lacking of shielding gas for laser beam is the dominant cause of macroporosity formation during the hybrid of laser-TIG welding of magnesium Alloys AZ31B plate, and hydrogen is not main cause to form large pores. A favorable weld without porosity can be obtained by appending lateral shielding gas for laser beam.
The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. Here we calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favourable for wave amplification from alpha energy. We find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large potential benefit. (Author).
The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. Here we calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favourable for wave amplification from alpha energy. We find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is shown to offer a large potential benefit. (Author).
The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the energy transfer, is investigated. This technique is ...
The authors used a near full-length human ornithine [delta]-aminotransferase cDNA, huOAT6, as a probe under low stringency hybridization conditions to identify a new autosomal ornithine [delta]-aminotransferase-related sequence (OATL3). Cloning and characterization of this sequence reveal it to be a partial nonprocessed pseudogene corresponding to exon 3 and flanking intronic sequences of the ornithine [delta]-aminotransferase structural gene. Using somatic cell hybrids and fluorescence in situ hybridization, they mapped OATL3 to 10q26, adjacent to the ornithine [delta]-aminotransferase structural gene locus. 13 refs., 3 figs.
Dynamic stability enhancement of composite mode oscillations of interconnected power systems by means of a hybrid power system stabilizer is discussed here. The proposed Hybrid PSS is of a two-level structure composed of a local PSS for local mode and a global PSS for inter-area mode damping. Here, the input of the global stabilizer is the center of inertia speed deviation of slow-coherent generators. The paper is focused on the practical considerations in implementation of the proposed stabilizer. First, the optimum allocation of this stabilizer is discussed. The authors introduce an index of mode-input-assignability, by which the best sites of the stabilizer can be identified. Next, for practical applications, an estimation method for the approximation of the input of the global PSS is introduced. An approximated value of the center of inertia speed is obtained from a suitable combination of the rotor speed data of a few properly selected key ...
Abstract Flame retardants (FRs) are used for in protection against fire. Organic inorganic hybrids could become one of the most promising FR solution in the future. In this paper, the synthesis, the characterization and the use as FRs and filler of grafted titania and alumina with 2 chloroethylphosphonic acid are presented. These hybrids contain 3.8 3.24% P and have good flame retardance when they are incorporated into unsaturated polyester resins. Alumina treated with 2 chloroethylphosphonic acid performed better than titania. The advantage of this approach is the use of these hybrid materials as filler and FR, in the same time, and the increase in flame retardancy by synergistic effect between alumina phosphorus and chlorine, for unsaturated polyester resins. Copyright 2010 John Wiley & ...
Purpose - Burr distribution has been proved to be a useful failure model. It can assume different shapes which allow it to be a good fit for various lifetimes data. Hybrid censoring is an important way of generating lifetimes data. The purpose of this paper is to estimate an unknown parameter of the Burr type XII distribution when data are hybrid censored. Design/methodology/approach - The problem is dealt with through both the classical and Bayesian point of view. Specifically, the methods of estimation used to tackle the problem are maximum likelihood estimation method and Bayesian method. Empirical Bayesian approach is also considered. The performance of all estimates is compared through their mean square error values. The paper employs Monte Carlo simulation to evaluate the mean square...
An innovative hybrid powder prepared using computer simulation allowed development of a new foundation having a fine, smooth texture that has never been achieved before. The optical structure/design of the powder was based on the results of measurements and analyses conducted on the optical characteristics of a baby's delicate skin, which is the envy of many women. To obtain the optimal optical characteristics, the finite differential time domain (FDTD) method for solving Maxwell's differential equation by difference and time domain was applied to the computer simulation method. For synthesis of the hybrid powder based on the optical model, a proprietary shape regulation coating technology was used in which flaky substrates were coated with microspherical forms of barium sulfate crystals. ...
Abstract A novel and convenient protocol for the preparation of an open-tubular column coated with chitosan-silica hybrid using chitosan and silane-coupling agent (-glycidoxy-propyltrimethoxysilane) was developed for CEC, in which, chitosan was covalently bonded to the inner wall of a fused-silica capillary using -glycidoxy-propyltrimethoxysilane as a cross-linking agent. The stationary phase was hydrophilic due to the chitosan-silica hybrid with abundant amine and hydroxyl functional groups. The chromatographic characteristics of the column were evaluated by the separation of some organic acids and inorganic anions. The column showed good selectivity for nucleotides, aromatic acids, and inorganic anions. The mechanism for the separation of these compounds was primarily based on the hydrop...
Tri layer hybrid composites of oil palm empty fruit bunches (EFB) and jute fibres was prepared by keeping oil palm EFB as skin material and jute as the core material and vice versa. The chemical resistance, void content and tensile properties of oil palm EFB/Jute composites was investigated with reference to the relative weight of oil palm EFB/Jute, i.e. 4:1, the fibre loading was optimized and different layering pattern were investigated. It is found from the chemical resistance test that all the composites are resistant to various chemicals. It was observed that marked reduction in void content of hybrid composites in different layering pattern. From the different layering pattern, the tensile properties were slightly higher for the composite having jute as skin and oil palm EFB as core ...
Much attention is being paid to electric vehicles from environmental standpoints. One disadvantage of the electric vehicle is that its operative range is short. A means to overcome this difficulty is to use a hybrid battery which consist of a energy battery and a power battery. A method to make it possible to calculate the discharge characteristics of the battery hybrid system taking into account the charging behavior from the energy battery to the power battery is presented. In the proposed method, first the output voltage and the output current of an equivalent battery, which is required for realizing the given operating pattern are calculated. Next, the conduction ratio of the main chopper and the equivalent discharge of electric charge of each battery are calculated. These calculated data are used to calculate the operating range.
The purpose of this project was to build a long-range, parallel hybrid gas/electric vehicle capable of driving beyond the communter capabilities of series hybrid vehicles. It was envisioned that since the gas engine would be able to independently propel the car when needed and that the electric motor would be capable of doing the same, then you have a very desirable situation where this car can operate much more cheaply on electricity for the short distance runs under approximately 60 miles and also be able to propel the vehicle via the gas engine on the long-distance trips. During the time the car would be operating in the gas engine mode, it would be also recharging the 16 deep cycle batteries via the electric motor now being used as a generator. Then, even on long-distance trips, the electric motor could be used, after having been fully or partially recharged, to even further reduce cost per mile.
We have investigated the superconducting and metallurgical properties of the ternary compounds RPd/sub 2/Si/sub 2/ and RRh/sub 2/Si/sub 2/ with R = Y, La, and Lu. All RPd/sub 2/Si/sub 2/ compounds and LaRh/sub 2/Si/sub 2/ were found to be type-I superconductors below 1 K. A detailed metallurgical analysis shows that segregation of second phases can easily mask the intrinsic (stoichiometric ratio 1:2:2) intermetallic-compound properties. Two sample-preparation techniques, viz., single crystals and off-stoichiometry, were utilized to establish where bulk superconductivity occurs. The type-I behavior of these compounds is explained with an analogous model as is used for the heavy-fermion superconductors CeCu/sub 2/Si/sub 2/ and URu/sub 2/Si/sub 2/.
Data by Wiesmann et al. on the temperature coefficient of the upper critical field, dH/sub c/2(T)/dT, and the normal-state resistivity rho_0 near the superconducting transition temperature T/sub c/ are analyzed to estimate the bare density of states N (E/sub F/) as a function of structural disorder and T/sub c/ in various #alpha#-particle irradiated samples of A-15 Nb_3Ge and Nb_3Sn. By taking into account the change in the electron-phonon coupling strength with T/sub c/ and the effect of mass enhancement arising from the electron-phonon interaction, the results of the new analysis indicate that (i) the drop in N (E/sub F/) for Nb_3Ge is relatively small as T/sub c/ changes from approx. 21 to approx. 4 K, in agreement with a recent low-temperature specific-heat measurement; (ii) the value of N (E/sub F/) in Nb_3Sn decreases by a factor of approx. 4 as T/sub c/ varies from approx. 18 to approx. 3 K. The implication of these findings is discussed in terms of the ...
We review the interplay of frustration and strong electronic correlations in quasi-two-dimensional organic charge transfer salts, such as k-(BEDT-TTF)_2X and Et_nMe_{4-n}Pn[Pd(dmit)2]2. These two forces drive a range of exotic phases including spin liquids, valence bond crystals, pseudogapped metals, and unconventional superconductivity. Of particular interest is that in several materials there is a direct transition as a function of pressure from a spin liquid Mott insulating state to a superconducting state. Experiments on these materials raise a number of profound questions about the quantum behaviour of frustrated systems, particularly the intimate connection between spin liquids and superconductivity. Insights into these questions have come from a wide range of theoretical techniques including first principles electronic structure, quantum many-body theory and quantum field theory. In this review we introduce the basic ...
Systematic studies of the NdFeAsOF superconducting energy gap using point-contact Andreev-reflection (PCAR) spectroscopy are presented. At low temperatures the PCAR conductance spectra show a pair of gap-like peaks at about {+-} (4-7) mV and in most cases also a pair of humps at around {+-} 10 mV. Fits to the s-wave two-gap model of the PCAR conductance allowed to determine two superconducting energy gaps in the system. However, the energy-gap features disappear at T* = 15-20 K, much below the particular T{sub c} of the junction under study. At T* a zero-bias conductance (ZBC) peak emerges, which at higher temperatures usually overwhelms the spectrum with an intensity significantly higher than the conductance signal at lower temperatures. Possible causes of this unexpected temperature effect are discussed. In some cases the conductance spectra show just a reduced conductance around the zero-bias voltage, the effect persisting well above the ...
The main LHC superconducting magnets (dipoles and quadrupoles) use Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with an overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a "composite" structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to ensure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique to check the quantity of solder in the joint is foreseen. The technique is based on a gamma ray source (241Am) and the detection is position-sensitive in the transmission mode. Scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the radioactive source (120 mm). The method can be ...
Microfabrication processes for Y-Ba-Cu-O films have been investigated, using ion-beam techniques. High-T_c superconducting lines as narrow as 0.8 #mu#m have been fabricated from epitaxial YBa_2Cu_3O_7 _- _y films by Ar ion-beam etching (IBE), combined with focused ion-beam (FIB) lithography. The resulting lines, 1.3 #mu#m wide and 2 mm long, showed a zero resistance temperature of 81 K and a critical current density of 1.9 x 10"4 A/cm"2 at 77.3 K. Maskless etching was carried out using 130-keV au"+ focused ion-beam (FIB) with a 0.1-#mu#m-diameter beam. A 50-nm-thick film was patterned into 0.3-#mu#m-wide lines at a dose of 5 x "1"6 ions/cm"2. In comparison with Ar IBE, Cl_2 reactive ion-beam etching (RIBE) exhibited an enhancement effect in sputtering yield. Ion implantation with 300-keV Si"+ "+ FIB also indicated the possibility to produce submicrometer patterns by selectively modifying film properties from superconductive to normal or ...
The resonance line shift of a series of A-15 structures (V_3Pt, Vsub(0.76)Ptsub(0.24) and Vsub(0.62)Irsub(0.38) is measured as a function of temperature in the superconducting state. A method will be described to separate the contribution of the diamagnetism of the superconductor (Meissner effect) and that of the Knight shift to this line shift. From the temperature dependence of the Knight shift of the V atoms the sum of the s and d contribution to the Knight shift can be determined. In these three compounds the s and d contributions appear to cancel out nearly. Moreover the temperature dependence of kappa_2 can be calculated from the measurements. The values of kappa_2 extrapolated at T=Tsub(c) are about 70 for these samples. From the obtained sum of Ksub(s) and Ksub(d) and the data of the susceptibility or of the specific heat of these samples Ksub(s) and Ksub(d) can be separated. For all samples Ksub(s)=0.06+-0.005%. Finally it was observed that the quadrupolar ...
Molar heat capacities have been measured for VHsub(n) and NbHsub(n) with n up to 1.93 at temperatures between 1.5 and 16 K. The height of the peak in plots of the electronic specific heat, indicating superconductivity, diminishes with increasing hydrogen content in the #alpha# + #beta# two-phase region, and can be taken as a measure of the fractional amount of #alpha#-phase present (lever-rule). In NbHsub(n) accordingly, the two-phase region presumably extends up to n = approximately 0.9 at helium temperatures. No hydride phase, including VH_2 and NbH_2, showed superconductivity above 1.5 K. The measured #gamma#-coefficients of the V/H-alloys agree with APW band-structure calculations for V metal in the range 5 =< nsub(e) =< 7 of band electron concentration. They coincide with the #gamma#-coefficients of V/Cr-alloys reported in the literature. Hence VHsub(n) represents another example of the 'shifting bands' concept developed recently for ...
Fault current limiters (FCLs) are devices for to suppress current in electric power system. The FCL is extensively expected to suppress fault current, particularly required for trunk power systems heavily connected high-voltage transmission lines, such as 500 kV class power system. For this reason, FCLs based on various principles of operation have been developed. Most of the FCLs under development which employ superconductors are based on the quenching phenomenon peculiar to the superconducting state, that is, making use of a rapid transition to normal conducting state, an electrical resistance appears, and this resistance is used to suppress fault currents. However, this elevation of resistance, although increasing the fault current suppression effect, also tend to raise the overvoltage occurring FCL, the ascertainment of the overvoltage is important as regards the protection of the FCL as well as other power system devices. Hence the waveform created in the FCL ...
The Neutron Science Project at Japan Atomic Energy Research Institute has been proposed for the research of nuclear transmutation technology and the basic science with a spallation neutron source. The project calls for an 8MW proton linac which accelerates 5.3mA average current cw and pulsed beams up to 1.5GeV. The superconducting (SC) rf-cavity is the main option for the energy part from 100MeV to 1.5GeV because by using the SC structure, less power is consumed in cw operation than by using a normal conducting (NC) structure. A conceptual design study of the superconducting proton linac is reported. The SC linac is composed of 8 {beta} sections. Each section has the identical 5-cell cavities with the surface peak field of 16MV/m. The total number of cavities is 284, and the length of the SC linac is 690m. The lattice design is determined with the equipartitioned condition and the matched envelope equations for the minimum emittance growth. The ...
The central aim of this thesis is to present a new kind of realism that is driven not from the traditional realism/anti-realism debate but from the practice of physicists. The usual debate focuses on discussions about the truth of theories and their fit with nature, while the real practices of the scientists are forgotten. The position I shall defend is called 'phenomenological realism': theories are merely tools to construct other theories and models, including phenomenological models; phenomenological models are the vehicles of representation. The realist doctrine was recently undermined by the argument from the pessimistic meta-induction, also known as the argument from scientific revolutions. I argue that phenomenological realism is a new kind of scientific realism which can overcome the problem generated by the argument from scientific revolutions, and which depend on the scientific practice. The realist tried to overcome this problem by suggesting various types ...
BackgroundWhile the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints....Full Text Available
Poplar (Populus tremula × alba) lignins with exceedingly high syringyl monomer levels are produced by overexpression of the ferulate 5-hydroxylase (F5H) gene...Full Text Available
In the absence of a vaccine, there is an urgent need for the development of safe and effective topical microbicides to prevent the sexual transmission of human immunodeficiency virus type 1 (HIV-1)....Full Text Available
Genome-wide studies of bacterial gene expression are shifting from microarray technology to second generation sequencing platforms. RNA-seq has a number of advantages over hybridization-based techniques,...Full Text Available
ColV plasmids of extraintestinal pathogenic Escherichia coli (ExPEC) encode a variety of fitness and virulence factors and have long been associated with septicemia and avian colibacillosis....Full Text Available
A previous report of high levels of members of the domain Archaea in Antarctic coastal waters prompted us to investigate the ecology of Antarctic planktonic prokaryotes. rRNA hybridization...Full Text Available
This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.
We report the first quantitative assessment of electrosprayed droplet/ion focusing enabled by the use of a voltage-assisted air amplifier between an electrospray ionization emitter and a hybrid...Full Text Available
A 308-size hybrid ball bearing, with ceramic balls and steel rings, was tested using a diester oil and gas turbine fuel as lubricants at several speeds and loads. Heat generation data from this test work was then correlated with the heat generation model from a widely used computer code. The ability of this hybrid split inner ring bearing design to endure thrust reversals, which are expected in many turbine applications, was demonstrated. Finally, the bearing was successfully endurance tested in JP-10 fuel for 25 hours at 7560 N axial load and 36,000 rpm. This work has successfully demonstrated the technology necessary to use fuel-lubricated hybrid bearings in limited-life gas turbine engine applications such as missiles, drones, and other unmanned air vehicles (UAVs). In addition, it has provided guidance for use in designing such bearing systems. As a result, the benefits of removing the conventional oil lubricant system, ...
BackgroundThe construction of cDNA libraries is a useful tool to understand gene expression in organisms under different conditions, but random sequencing of unbiased cDNA collections...Full Text Available
The indoor climate of school buildings have been much debated recently. Many problems connected with air quality and thermal comfort are caused by bad maintenance, fitted carpets and no sunshades. Mechanical ventilation in schools has gained a bad reputation and many municipalities are seeking other solutions when building new schools. Natural ventilation according to the ''Swedish model'' does not use air filters or heat recovery from the outgoing air and achieve low energy consumption by reducing the airflow substantially in cold weather. Most of the naturally ventilated schools have supply air culverts of concrete below ground outside the building and in the basement. This is also true of schools using hybrid ventilation, where natural and mechanical ventilation is combined. The naturally ventilated schools often use manual control of the ventilation, which may not always be a good solution for buildings with changing types of ...
A quantitative energy pathway comparison is made between a modern oil refinery and genetic fusion hydrogen plant supporting hybrid-electric cars powered by gasoline and hydrogen-optimized internal combustion engines, respectively, both meeting President Clinton's goal for advanced car goal of 80 mpg gasoline equivalent. The comparison shows that a fusion electric plant producing hydrogen by water electrolysis at 80% efficiency must have an electric capacity of 10 GWe to support as many hydrogen-powered hybrid cars as one modern 200,000 bbl/day-capacity oil refinery could support in gasoline-powered hybrid cars. A 10 GWe fusion electric plant capital cost is limited to 12.5 B$ to produce electricity at 2.3 cents/kWehr, and hydrogen production by electrolysis at 8 $/GJ, for equal consumer fuel cost per passenger mile as in the oil-gasoline-hybrid pathway.
Radixin is a cytoskeletal protein that may be important in linking actin to the plasma membrane. Recent cloning of the murine and porcine radixin cDNAs revealed a protein highly homologous to ezrin and moesin. The authors have cloned and sequenced the human radixin cDNA and found the predicted amino acid sequence for the human protein to be nearly identical to those predicted for radixin in the two other species. By Southern analyses of Chinese hamster x human somatic cell hybrid DNA and of PCR products derived from hybrids, the coding gene (RDX) was mapped to 11q. Fluorescence chromosomal in situ hybridization with a cDNA plasmid further localized this gene to band 11q23. However, PCR amplification with [open quotes]radixin-specific[close quotes] primers on the hybrid DNA panel yielded an additional, very similar DNA sequence that was further characterized by direct sequencing of PCR products. This ...
The percentages of total airflows over the nasal respiratory and olfactory epithelium of female rabbits were calculated from computational fluid dynamics (CFD) simulations of steady-state inhalation....Full Text Available
The interior of 237 nm spherical vinylsilsesquioxane nanoparticles has been covalently modified and their surface functionalized under mild conditions to yield a novel type of hybrid silsesquioxane...Full Text Available
Hybridization and thermal evolution of the Ni+C{sub 60} composites, deposited on Si(001) at room temperature, were studied using Scanning Electron Microscopy, {mu}-Raman spectroscopy and Rutherford Backscattering. As-deposited, the hybrid films exhibited a granular nano-structure with Ni nano-particles encapsulated in C{sub 60} polymerized rinds. The Ni and C (C{sub 60}) distributions in a top layer were found homogeneous with a stable Ni/C (C{sub 60}) ratio; in the larger depth the distributions were inhomogeneous and their ratio dramatically varied. At elevated temperatures, all structural parameters were changed. In the subsurface layer Ni- and C (C{sub 60})-rich zones were formed (due to the induced phase separation), C{sub 60}-molecules decayed and their fragments were transformed into amorphous carbon (a-C). The free volume distribution of the stressed hybrid matter was analyzed by the Hg marker that (in a form of ...
BackgroundPopulation densities of many species throughout the world are changing due to direct persecution as well as anthropogenic habitat modification. These changes may induce...Full Text Available
In the interests of fuel economy in motor vehicles, this article discusses the importance of waste heat recovery and then goes on the explore options such as hybrid electric cars, thermal engines with low loss platforms, pure electric vehicles and fuel cell vehicles. (UK)
The effect of growth phase on expression of virulence-associated factors was studied by Northern hybridization in an M1T1 clinical isolate of Streptococcus pyogenes. Expression of M...Full Text Available
This book contains papers relating to the 1990 Future Transportation Technology Conference and Exposition. Included are the following papers; Examination of rich mixtures operation of a dual fuel engine, A hybrid natural gas vehicles, Performance analysis of a spark ignited engine with ETBE as a blending agent.
Tissue culture conditions and transformation have been established for both aspen and poplar. The use of previously described culture conditions resulted in shoot tip necrosis in the shoot cultures...Full Text Available
A compact dedicated 3D breast SPECT-CT (mammotomography) system is currently under development. In its initial prototype, the cone-beam CT sub-system is restricted to a fixed-tilt circular rotation...Full Text Available
Considering accessibility of the 3′UTR is believed to increase the precision of microRNA target predictions. We show that, contrary to common belief, ranking by the hybridization energy or by...Full Text Available
DNA barcodes linked to genetic features greatly facilitate screening these features in pooled formats using microarray hybridization, and new tools are needed to design large sets of barcodes to allow...Full Text Available
The biocompatibility and corrosion resistance of various materials for use as sacrificial anodes in in vivo hybrid fuel cells were studied. Aluminium, zinc, and magnesium alloy AZ31B were studied, and the results are discussed.
Cyteogenetic maps of sorghum chromosomes 3-7, 9, and 10 were constructed on the basis of the fluorescence in situ hybridization (FISH) of ~ ... regions of heterchromatin were delimited for all 10 sorghum chrom...
Car-producers compete in launching hybrids and electric cars, but this does not mean the end for the good old combustion engine.The challenge is the introduction of more complexed costs and weight in the new technology. (AG)
BackgroundThe purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).MethodsTwenty-three...Full Text Available
In situ hybridization, a powerful tool for the molecular cytogeneticist, can be used to physically map repetitive, low-copy, and unique DNA sequences in plant chromosomes. With the availability of a...Full Text Available
A high-throughput assay for enzyme activity has been developed that is reaction independent. In this assay, a small-molecule yeast three-hybrid system is used to link enzyme catalysis to transcription...Full Text Available
The human genome contains greater than 20 actin-related sequences, six of which at least are expressed as protein. We have shown by blot hybridization the presence of actin-like sequences on both the...Full Text Available
The single-stranded viral DNA of an M13 phage recombinant containing the early promoter region of SV40 was hybridized with linear, double-stranded replicative form DNA of a related M13 phage containing...Full Text Available
BackgroundThe commonest pathogenic DMD changes are intragenic deletions/duplications which make up to 78% of all cases and point mutations (roughly 20%) detectable...Full Text Available
The biosynthetic costs of phenylpropanoid-derived condensed tannins (CTs) and phenolic glycosides (PGs) are substantial. However, despite reports of negative correlations between leaf phenolic content...Full Text Available
Picocyanobacteria of the genus Synechococcus are important contributors to marine primary production and are ubiquitous in the world's oceans. This genus is genetically diverse, and...Full Text Available
The offline adaptive radiotherapy (ART) has been used to effectively correct and compensate the prostate motion and reduce the required margin. The efficacy depends on the characteristics of...Full Text Available
The primary method for neuronal communication involves the extracellular release of small molecules that are packaged in secretory vesicles. We have developed a platform to separate, lyse, and...Full Text Available
The Wendelstein 7-X (W7-X) modular stellarator is under construction at the Max-Planck-Institut fur Plasmaphysik in Greifswald, Germany. The W7-X magnet system contains 70 coils made up from helium cooled superconducting cables in aluminium alloy (EN AW-6063) jackets. Several hundred connections of the jacket to the cable joints are made by aluminium-to-aluminium welds. Due to geometrical and thermal boundary conditions these welds cannot be accomplished free from defects. Microscopic analyses of the welds show that a variety of small flaws such as cracks and pores develop during welding. The welds have thus to be dimensioned accordingly, and appropriate weld qualification, investigation and testing has to be done in order not to jeopardise the structural integrity and leak tightness. The ...
The frequency dependence of the tunneling spectrum #alpha#"2F (#omega#) is analyzed in terms of electron pairing induced by exchange of acoustic plasmons in addition to the usual phonon-exchange mechanism. Analytic expressions are obtained for the electron self-energy, the tunneling function #alpha#"2F, and the electron pairing coupling lambda which determines the superconducting properties. The resulting theory is applied to recent tunneling data of Nb_3Sn in order to examine the anomalous discrepancies with the phonon density of states found by neutron scattering experiments. The results demonstrate how the high-temperature (T/sub c/ approx. 20 "0K) superconducting properties of A-15 compounds are enhanced by acoustic-plasmon contributions, and thus they reconcile these high transition temperatures with the relatively small values of the phonon part of lambda estimated from several independent experiments.
The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860[degrees]C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.
The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860 degrees C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.
The critical superconducting paramters of A-15 compounds are reviewed, and the trends analysed in order to predict maximum values. Experimental data on critical temperature is summarized and compared with theory. The ability to form the stoichiometric, well-ordered materials required for maximum Tsub(c) is discussed in terms of the thermodynamic stability of the A-15 phase. It is concluded that critical temperatures in excess of 25 K, in the A-15 structure, are unlikely. The upper critical field data show that, whereas the vanadium-based compounds are paramagnetically limited, the niobium-based compounds are not. The relation between critical current and microstructure is explored. Best data on critical current densities and ac losses is presented. Finally an account is given of the various methods by which actual conductors, both tapes and multifilamentary wires, are made. (author).
With the preeminence of A-15 superconducting multifilamentary wires in magnet technology, it has become important to understand the thermodynamic factors influencing the formation of these compounds under solid-state reaction conditions. The six systems Nb--Sn, Nb--Ga, Nb--Ge, Nb--Al, V--Si, and V--Ga were prepared as single filament bronze wires and heat treated in an attempt to precipitate the appropriate A-15 compound. The compounds observed to form were categorized using a formation temperature ratio (stability index) based on the melting temperatures of the constituents which make up the single filament composites. This study has led to several predictions regarding the formation of A-15 compounds using a solid-state bronze diffusion technique. The results of experimentation based on these predictions are presented.
Recent progress in yttrium-based oxide high-temperature superconductors has enabled the production of a large diameter bulk with a strong flux-pinning force. A combination of this superconductor and a permanent magnet makes it feasible to fabricate a noncontact, non-controlled superconducting magnetic bearing with a very small rotational loss, applicable to a flywheel energy storage system. A conceptual design of an 8 MWh flywheel energy storage system using the new bearing has been developed, based on measured data on a miniature bearing model, which proved to be potentially capable of achieving a high energy storage efficiency of 84 pc. A 100 W h-class experimental system was then built, which attained a high revolution rate of 17000 rpm, with a rotational loss of about 0.6 W. (authors). 2 refs., 7 figs., 3 tabs.
The ternary rare earth compound NdRh_4B_4 has been studied by means of critical field, low temperature heat capacity, and static magnetic susceptibility measurements. Features in the upper critical field and heat capacity data at 1.31 K and 0.89 K suggest the occurrence of long-range magnetic order in the superconducting state. The temperature dependence of the static magnetic susceptibility follows a Curie-Weiss law with an effective magnetic moment #mu#sub(eff) = 3.58 +- 0.05 #mu#sub(B) and a Curie-Weiss temperature thetasub(p) = -6.2 +- 1.0 K between 20 K and room temperature. However, magnetization vs. applied magnetic field isotherms suggest the development of a ferromagnetic component in the Nd"3"+ magnetization at low temperatures. (author).
The phase diagram of Gdsub(x)Ysub(1-x)Th_4B_4 between the paramagnetic, superconducting and ferromagnetic state is reported. Low temperature dc-magnetization measurements reveal that macroscopic electro-magnetic effects are of minor importance for the suppression of Hsub(2c), which shows a smooth bell-shaped behavior for x >= 0.15 with no indication of an anomaly near Tsub(c2). At low temperature in samples with x >= 0.20 a transition from type II to type I superconductivity seems to occur. The low temperature normal state susceptibility follows a Curie-Weiss law indicating reentrant behavior for x >= 0.10. (orig.).
A method for determining the mobility of hydrogen as a function of temperature in superconducting niobium cavities comprising: 1) heating a cavity under test to remove free hydrogen; 2) introducing hydrogen-3 gas into the cavity; 3) cooling the cavity to allow absorption of hydrogen-3; and 4) measuring the amount of hydrogen-3 by: a) cooling the cavity to about 4.degree. K while flowing a known and regulated amount of inert carrier gas such as argon or helium into the cavity; b) allowing the cavity to warm at a stable rate from 4.degree. K to room temperature as it leaves the chamber; and c) directing the exit gas to an ion chamber radiation detector.
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd{sub 2}Si{sub 2}. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of {rho}(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd_2Si_2. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of #rho#(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
Sensitive and quick-response nonlinear inductance characteristics are found for high Tc superconducting (YBa/sub 2/Cu/sub 3/O/sub 7-chi/) disk cores at 77K in which soft magnetic BH hysteresis loops are observed. Various quick response magnetic devices such as modulators, amplifiers and sensors are built using these cores. The magnetizing frequency can be set to more than 20 MHz, which is difficult for conventional ferromagnetic bulk materials such as Permalloy amorphous alloys and ferrite. New quick-response fluxgate type magnetic-field sensors are made using ac and dc voltage sources. The former is used for second-harmonic type sensors, while the latter is for voltage-output multivibrator type sensors. Stable and quick-response sensor characteristics were obtained for two-core type multivibrators.
The superconducting magnets and associated cryogenic components in A-sector represent the initial phase of installation of the Fermilab superconducting accelerator, designed to accelerate proton beams to energies of 1 TeV. Installation of the magnets, comprising one-eighth of the ring, was completed in December, 1981. Cooldown and power tests took place in the first half of 1982, concurrent with main ring use for 400 GeV high energy physics. The tests described in this paper involved 151 cryogenic components in the tunnel: 94 dipoles, 24 quadrupoles, 25 spool pieces, 3 feed cans, 4 turn-around boxes and 1 bypass. Refrigeration was supplied by three satellite refrigerators, the Central Helium Liquefier, and two compressor buildings. The magnets were powered by a single power supply.
The electronic structures of BaSnO_3, BaSbO_3, and BaPbO_3, calculated using an extended general-potential linearized augmented-plane-wave method, are reported. The electronic structures of BaSnO_3 and its 6s analog BaPbO_3 are found to be very different, explaining the absence of superconductivity in the Ba(Sn,Sb)O_3 system. These differences are explained by a combination of the relativistic lowering of the 6s states and ion-size effects. Muffin-tin-approximation augmented-plane-wave calculations for BaSnO_3 are also reported and the utility of the muffin-tin approximation for this and similar materials is discussed in terms of the differences between the two sets of calculations.
We have calculated the electronic structure of Eu for the bcc, hcp, and fcc crystal structures for volumes near equilibrium up to a calculated 90 GPa pressure using the augmented-plane-wave method in the local-density approximation. The frozen-core approximation was used with a semi-empirical shift of the f-states energies in the radial Schroedinger equation to move the occupied 4f valence states below the #GAMMA#_1 energy and into the core. This shift of the highly localized f-states yields the correct europium phase ordering with lattice parameters and bulk moduli in good agreement with experimental data. The calculated superconductivity properties under pressure for the bcc and hcp structures are also found to agree with and follow a T_c trend similar to recent measurement by Debessai et al.
The Superconducting Super Collider uses approx. =9600 dipole magnets. The magnets have been carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor/coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. For the most efficient use of axial space in the magnet, and lowest possible current, a distributed internal correction coil design is planned. The trim coil assembly is secured to the beam tube, a uhv tube with special strength, size, conductivity and vacuum. The report details the SSC trim coil/beam tube assembly specifications, history, and ongoing development.
To study the nanoscale electronic order in strongly correlated electron systems and vortex states in high-Tc superconductors in high magnetic fields, we have developed scanning tunneling microscopy (STM) for the 18 T cryocooled superconducting magnet (18T-CSM). The test results of the STM operation in the 18T-CSM at room temperature indicate that our STM has a good atomic resolution up to 18 T when we use the nonmagnetic vibration-isolation table which reduce the vibration noise from the cryocoolers of the 18T-CSM. In this paper, we report on the design of the high-field STM system for large-scale magnets and its performance.
A high-average power (kW) infrared (IR) free-electron laser (FEL) is currently being commissioned for the Jefferson Laboratory FEL User Facility. The IR FEL is driven by a unique superconducting rf linac which is recirculated to recover electron beam power that is not radiated in the FEL. The design and installation of the vacuum system for the FEL involved particular attention to minimizing particulate contamination which could cause problems with the superconducting acceleration cavities and the high power FEL optics. Particulate contamination levels of all vacuum components were monitored during the cleaning process using laser scattering. Cleaning, transport, and installation procedures were developed to minimize the contamination of the complete system. We will summarize a data base we compiled of particulate contamination levels of the various components installed in the FEL vacuum system.
The influence of irradiation with 2.6 MeV H and He nuclei on the superconducting properties (critical temperature Tsub(c), critical current Isub(c)) of the intermetallic compound Nb_3Sn was studied. Irradiation led to a significant lowering of Tsub(c), while Isub(c) is increasing with the radiation dose. This is assumed to be due to the formation of active pinning centres in the lattice. There is a fast drop of Isub(c) after a peak value has been reached. Annealing of the samples (600-1,000"0C) led to an almost complete recovery of the initial value of Tsub(c). X-ray diffraction showed that irradiation causes considerable distortions of the lattice while the A15 crystal structure is retained. The causes of the radiation effects related to structural defects are discussed. (GSCH).
Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths (#lambda# = 0.3...20 #mu#m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.
The plastic deformation behavior of formed CICC for the superconducting Tokamac fusion device was examined and appropriate manufacturing information was provided. A relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. The maximum von Mises stress after spring back was also monitored for the SAGBO prediction. Next, the variation of the CICC cross-sectional area was examined during the first turn and during conduit bending with the largest curvature. Finally, the coil radius was measured and compared with the data generated from the virtual manufacturing. The measured data showed similar pattern as predicted one. Using the mapping function found to match with the real data, the data from the virtual manufacturing may facilitate accurate manufacturing.
The plastic deformation behavior of formed CICC for the superconducting Tokamac fusion device was examined and appropriate manufacturing information was provided. A relation between travel of the bending roller and spring back displacement was obtained via virtual manufacturing. The radius of CICC after forming was expressed as a function of the bend-roll travel. The maximum von Mises stress after spring back was also monitored for the SAGBO prediction. Next, the variation of the CICC cross-sectional area was examined during the first turn and during conduit bending with the largest curvature. Finally, the coil radius was measured and compared with the data generated from the virtual manufacturing. The measured data showed similar pattern as predicted one. Using the mapping function found to match with the real data, the data from the virtual manufacturing may facilitate accurate manufacturing.
The thermal recovery of superconducting elements working as secondaries in fault current limiters can be enhanced by taking advantage of the removal of heat by conduction from an array of artificial weak zones (AWZ) distributed along the superconductor perimeter (hot parts) to the non-weak segments (cold parts). These results were obtained by studying samples with weak parts in the shape of grooves, all identical in size. In this paper we consider the case in which one of the AWZ is slightly different from the rest. Our results show that a change in its length has a negligible effect. On the contrary, a groove which is slightly deeper can be overheated and hence can strongly determine the recovery time of the whole limiter.
Spectroscopy based on the Andreev reflection (AR) process at the interface between the normal metal tip and the superconductor has become one of the very successful methods for studies in novel exotic superconductors. The method is capable to address the size, symmetry as well as multiplicity of the superconducting order parameter. The method provided one of the first evidences of the two-gap superconductivity in MgB{sub 2} with a detailed temperature dependence of the both gaps. A theory treating the Andreev reflection spectroscopy in the mixed state is missing. We analyse the AR spectra of MgB{sub 2} in the mixed state via modelling the magnetic pair-breaking by the increasing spectral broadening parameter {gamma}. As a result a non-trivial pair breaking effect in the {pi}-band is found.
The change of superconducting properties after neutron irradiation in A-15 compounds such as Nb_3Sn. Nb_3Al. V_3Ca and V_3Si has been examined. Using the model based on the damage function, the change of transition temperature corresponding to an arbitrary irradiation dose within about 10"2"0n/cm"2 can be predicted with an accuracy of several percent for Nb_3Al. Nb_3Sn and V_3Si if experimental data, namely a pair of irradiation dose and transition temperature, is given. The calculation of transition temperature of neutron irradiated A-15 compounds is much more straightforward than in the case of Pande's model. (author).
We present a new aspect of superconductivity in A-15 compounds which is able to explain their exceptional role among the high Tc superconductors. The basic idea is that a strong energy dependence of the the electronic density of states near the Fermi level may greatly reduce the repulsive part of the frequency dependent electron-phonon interaction. This leads to a large enhancement of Tc which is a maximum when the Fermi energy is comparable to a typical phonon energy. Our findings are based on numerical solutions of the Eliashberg equations where both the retardation of the electron-phonon coupling and the energy dependence of the electronic density of states have been included. For the electronic density of states we use the models of Labbe and Friedel and of Cohen et al., while the shape of the Eliashberg function #alpha#"2F(#omega#) is taken from the tunneling results of Shen. We compare our theory to experimental results for ternary A-15 compounds. (orig.).
Mitsubishi is now developing a new Pressurized water reactor (PWR), the Mitsubishi simplified PWR (MS-PWR), which has the innovative features of hybrid safety systems (an optimum combination of passive and active systems) and cooling by horizontal steam generators. In order to confirm the feasibility of the Mitsubishi hybrid safety system, various kinds of safety analyses are performed for loss-of-coolant accident events. In parallel to these safety analysis efforts, the following thermal-hydraulic tests are to be performed: (1) thermal-hydraulic test of a horizontal steam generator; (2) integrated thermal-hydraulic test using a simulation loop for the innovative MS-PWR (SLIM).
pD10 is a 0.85 kb fragment with BamHI ends cloned in pSP64. It was sub-cloned from {lambda}D10 which was isolated from a genomic library constructed in {lambda}EMBL3 from a rodent human somatic cell hybrid. The probe was localized to 19q13.2-19qter on a panel of rodent human somatic cell hybrids. Co-dominant segregation was shown in 32 families of 280 individuals.
One of the major scientific and technological challenges for the production of flexible organic electronic devices is the device protection against atmospheric molecule permeation, which causes corrosion reducing its operation and lifetime. In this work, Spectroscopic Ellipsometry has been implemented to investigate the influence of silicon dioxide nanoparticles on the optical properties of hybrid polymers. The spectra analysis revealed valuable information about the electronic and vibrational response as well as the cross-linking mechanisms of these materials. The correlation of the optical properties with the synthesis parameters and the barrier response will contribute towards their optimization in order to be used as high barrier coatings for flexible organic electronics applications.
This paper presents the analysis and novel hybrid controller design for an interleaved 2-quadrant switched capacitor (SC) bidirectional DC/DC converter for a hybrid electric vehicle (HEV) dual energy storage system. The designed novel control strategy enables simpler dynamics compared to a standard buck converter with input filter, good regulation capability, low EMI, lower source current ripple, ease of control, and continuous input current waveform in both buck as well as boost modes of operation.
We investigate stability properties of indirectly damped systems of evolution equations in Hilbert spaces, under new compatibility assumptions. We prove polynomial decay for the energy of solutions and optimize our results by interpolation techniques, obtaining a full range of power-like decay rates. In particular, we give explicit estimates with respect to the initial data. We discuss several applications to hyperbolic systems with {\\em hybrid} boundary conditions, including the coupling of two wave equations subject to Dirichlet and Robin type boundary conditions, respectively.
An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperature having an aperture axis, the aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver.
DescriptionThis project aims to develop a hybrid bioremediation/phytoremediation process for sustainable in- situ treatment of hydrocarbon contaminated soils, centred on 3 tenets: 1) Application of wood-chip derived compost enriched with white rot fungi for primary bioremediation; 2) Growth of pre-selected plant species for secondary phytoremediation; 3) Use of stress- adapted mycorrhizal fungi to maximise plant performance. A multidisciplinary approach is essential to optimise bioremediation for the trea [continued...
An energy control strategy (10) for a hybrid electric vehicle that controls an electric motor during bleed and charge modes of operation. The control strategy (10) establishes (12) a value of the power level at which the battery is to be charged. The power level is used to calculate (14) the torque to be commanded to the electric motor. The strategy (10) of the present invention identifies a transition region (22) for the electric motor's operation that is bounded by upper and lower speed limits. According to the present invention, the desired torque is calculated by applying equations to the regions before, during and after the transition region (22), the equations being a function of the power level and the predetermined limits and boundaries.
Theoretical description of Raman scattering in disordered alloys of Ti and Zr with transition metals of groups 5-8 of the Mendeleev Periodic System in critical range of concentrations (CRC) is given. Results of Raman scattering experiment in the system Ti_1_-_xF_x at 0.0005hybridization potential and energy of impurity zone, as well as their concentrational dynamics, are determined. Qualitative adequacy of the hybridization model to the alloys studied near CRC is shown.
This report describes the progress achieved in developing electric and hybrid vehicle technologies, beginning with highlights of recent accomplishments in FY 1992. Detailed descriptions are provided of program activities during FY 1992 in the areas of battery, fuel cell, and propulsion system development, and testing and evaluation of new technology in fleet site operations and in laboratories. This Annual Report also contains a status report on incentives and use of foreign components, as well as a list of publications resulting from the DOE program.
In the quest to understand the ultimate nature of WIMPs, we propose the use of a hybrid detection technique: cylinders filled with liquefied noble gasses, acting as targets, are immersed inside a tank of Gd-doped ultra-pure water that provides an active and efficient veto against neutrons. The evaluation of the background rejection capabilities and physics potential of this instrument have been carried out through a full GEANT4 simulation, assuming the detector will be located at the Canfranc underground laboratory (in the Spanish Pyrenees). Our results compare very favourably with existing or planned experiments in the field. This technique is scalable and will allow to reach target masses of few tonnes in the next future.
Human BTEB cDNA clones have been isolated, sequenced, and the corresponding gene has been assigned to human chromosome 9, region q13, by fluorescent in situ hybridization and DNA blot analysis using DNAs from hybrid cell clones containing a single human chromosome. The cDNA clone encodes a polypeptide of 244 amino acids whose sequence shows a high sequence similarity with the rat BTEB (98% amino acid identity).
The global demand for platinum has consistently outgrown supply in the past decade. This trend likely will continue and the imbalance may possibly escalate into a crisis. Platinum plays pivotal roles in both conventional automobile emissions control and the envisioned hydrogen economy. A platinum crisis would have profound implications on energy and environment. On the one hand, inadequate platinum supply will prevent widespread commercialization of hydrogen fuel-cell vehicles. On the other hand, expensive platinum may enhance the competitiveness of hybrid, plug-in hybrid, and battery-powered electric cars. Policymakers should weigh the potential impacts of a platinum crisis in energy policy.
The school building complex Waterland in The Hague, Netherlands, was built with a hybrid ventilation system. The indoor environment and energy consumption were monitored for one year. Air quality and thermal comfort are of a high quality and the consumption of energy for heating is circa 35% lower than normal. The Waterland project was one of eight demonstration projects, carried out within the framework of the ECBS-Annex 35: Hybrid ventilation in New and retrofitted Office Buildings. ECBS stands for the IEA-program Energy Conservation in Buildings and Community Systems. [Dutch] In ECBCs-annex 35 (ECBS staat voor het IEA-programma Energy Conservation in Buildings and Community Systems) is uitgebreid onderzoek gedaan naar hybride ventilatiesystemen in kantoren en scholen. Dit project heeft geleid tot acht internationale voorbeeldprojecten, waarvan scholencomplex Waterland te Den Haag er een van is. Het scholencomplex is in ...
6 mm diameter current leads made of M1, M3 copper and L62 brass are tested for extension of operation range of current leads supplying superconducting devices submerged into the cryostat. Data characterizing the effect of material purity on lead superheating are obtained. A theoretical model permitting to obtain analytical dependences for calculating the current lead maximum temperature is proposed and the possibility of its decrease by increasing current lead diameter in the hot part is considered.
A network of second-generation low-temperature gravitational radiation detectors is nearing completion. These detectors, sensitive to mechanical strains of order 10"-"1"8, are possible because of a variety of technical innovations that have been made in cryogenics, low-noise superconducting instrumentation, and vibration isolation techniques. Another five orders of magnitude improvement in energy sensitivity of resonant-mass detectors is possible before the linear amplifier quantum limit is encountered. 33 references, 3 figures, 1 table.
A prototype for a quasi-cw, and high-average power free electron laser (FEL) driven by a 15 MeV superconducting rf linac has been developed, and constructed at Tokai, JAERI since 1989. Cryogenic and accelerating fields' performances of four JAERI superconducting accelerator modules have been realized without any serious problem in the FEL accelerator vault and experimental hall. Since modification and related maintenance of the cryogenic refrigerator system for the driver were completed in the middle of October 1995, the system has run with no trouble, and the driver has been continuously run very successfully up to now. The optical resonator system and related electron beam transport system have been modified to realize larger acceptance than the old for both of the undulator radiation and energetic electron beam in 1995 Japanese fiscal year. In the modification, an alignment and distance measurement system has been newly developed, and ...
It is suggested that the large reduction of the superconducting transition temperature Tc due to defects observed experimentally in some A-15 compounds is caused by smearing of a high peak in the density of states at the Fermi level. The influence of defects on other physical properties (the magnetic susceptibility ?, the elastic modulus Cs, the structural transformation temperature Tm and the electrical resistivity ?) is also discussed from the same point of view. We expect the anomalous temperature dependence of ?, Cs and ? will be suppressed by defects.
Solutions have been found for the problems encountered with the coil power and switching systems of the International Fusion Superconducting Magnet Test Facility (IFSMTF). The coil power system provides the filtered dc sources (+- 12 V dc; 25,000 A) for charging and discharging the coils of the IFSMTF experiment. The switching system provides the means of transferring the coil current into a dump resistor when a rapid discharge of a coil is required due to a coil failure (quench) or other system abnormalities.
The existence of a narrow peak of electron state density in A-15 is explained by a strong electron-phonon interaction that brings about the polaron narrowing of zone. In the supposition of weak and intermediate bond, the analytical expression for the critical transition temperature is found that corre lates Tsub(c) with phonon spectrum. The model permits to explain Tsub(c) correlation with the number of electrons per atom, temperature direction of resistance, value and temperature dependence of magnetic susceptibility and electron thermal capacity.
The existence of a narrow peak of electron state density in A-15 is explained by a strong electron-phonon interaction that brings about the polaron narrowing of zone. In the supposition of weak and intermediate bond, the analytical expression for the critical transition temperature is found that corre lates Tsub(c) with phonon spectrum. The model permits to explain Tsub(c) correlation with the number of electrons per atom, temperature direction of resistance, value and temperature dependence of magnetic susceptibility and electron tehrmal capacity.
It is shown that both the Tsub(c) and Tsub(m) dependences on the deformations and composition for the A-15 compounds can be described at least qualitatively in the quasi-one-dimensional model developed by the authors previously. The mechanism for the superconductivity is supposed to be the same as in the BCS theory. The upper critical field near Tsub(c) is obtained. (author).
Here we report normal-state conductance measurements of three different types of superconducting tunnel junctions that are being used or proposed for quantum computing applications: p-Al/a-AlO/p-Al, e-Re/e-AlO/p-Al, and e-V/e-MgO/p-V, where p stands for polycrystalline, e for epitaxial, and a for amorphous. All three junctions exhibited significant deviations from the parabolic behavior predicted by the WKB approximation models. In the p-Al/a-AlO/p-Al junction, we observed enhancement of tunneling conductances at voltages matching harmonics of Al-O stretching modes. On the other hand, such Al-O vibration modes were missing in the epitaxial e-Re/e-AlO/p-Al junction. This suggests that absence or existence of the Al-O stretching mode might be related to the crystallinity of the AlO tunnel barrier and the interface between the electrode and the barrier. In the e-V/e-MgO/p-V junction, which is one of the candidate systems for future superconducting ...
A "9"2Mo beam with an energy of E/A=70 MeV has been used to produce new isotopes near the proton drip line. The Michigan State University National Superconducting Cyclotron Laboratory A1200 fragment separator was used to detect the new isotopes "7"8Y, "8"2Nb, "8"5Mo, "8"6Tc, and "8"9","9"0Ru.
A {sup 92}Mo beam with an energy of {ital E}/{ital A}=70 MeV has been used to produce new isotopes near the proton drip line. The Michigan State University National Superconducting Cyclotron Laboratory A1200 fragment separator was used to detect the new isotopes {sup 78}Y, {sup 82}Nb, {sup 85}Mo, {sup 86}Tc, and {sup 89,90}Ru.
Horizontal beam orbit jitter at frequencies around 10 Hz has been observed in RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta quadrupole triplets around the ring, where they coincide with mechanical modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations.
The structural instability in high temperature A-15 superconductors is examined from a phenomenological, Landau theoretic point of view, based on the picture of an electronically driven lattice instability. emphasis is given to lattice properties--in particular, the extended softening of phonons in k-pace and phonon linewidth. Implications of the extended softening on the microscopic picture of the transition, and the interplay between structural and superconducting instabilities in the A-15 compounds are discussed.
This paper describes a process for the direct production of a superconductive niobium-titanium alloy during reduction of niobium pentoxide. It comprises: mixing at least one of titanium metal powder and titanium dioxide powder with niobium pentoxide powder and aluminum powder; heating the resulting mixture to form a niobium-titanium alloy and a slag consisting essentially of aluminum oxide; and separating the alloy and the slag.
Radionuclide x-ray fluorescence analysis was used for the determination of Y, Ba and Cu in thin high-temperature superconducting films. Atomic emission ICP spectrometry was used to estimate the precision and accuracy of analytical results. Reasonable agreement between both methods was obtained when a polynomial calibration curve was applied. (author) 4 refs.; 4 tabs.
Helical dipole magnets are required in a project for the Relativistic Heavy Ion Collider (RHIC) to control and preserve the beam polarization in order to allow the collision of polarized proton beams. Specifications are for low current superconducting magnets with a 100 mm coil aperture and a 4 Tesla field in which the field rotates 360 degrees over a distance of 2.4 meters. A magnet meeting the requirements has been developed that uses a small diameter cable wound into helical grooves machined into a thick-walled aluminum cylinder.
We use a massively parallel 3D hybrid particle code, dHybrid, to simulate the deflection of plasma beams by a dipole like magnetic field in a laboratory environment. Dipole magnetic fields, along with a plasma injection source to inflate the magnetic field, are now being studied as means of deflecting solar wind and Energetic Particles away from spacecrafts [1,2,3]. We have considered three setups, consistent with the experiments, with a plasma beam fired at i) a dipole field with no plasma injection, ii) a plasma injection source with no dipole field and iii) a dipole field with a plasma injection source. The hybrid simulations help understand the relevant physical phenomena, and enable extrapolation to space plasma scenarios, where setups are similar but plasma parameters differ significantly. The simulation results consistently show the plasma beam being deflected by the dipole field, in the first scenario, with the ...
A study was made for the purpose of electrification of unelectrified zones of the mountainous areas in developing countries using extremely small hydroelectric power facilities. The target for this project is a development of a micro hydroelectric power system with a size of about 5kW, which is estimated regarding that 1 village has 80 houses and each house needs electricity of 60W. In the study, the low-head system using a weir of irrigation channels in Subang pref. of West Java state was selected by the evaluation of access, stability of flow rate, natural conditions, etc. The hydroelectric power plant is of a flow-in method in which water is taken from the left bank and is injected/discharged to the downstream of the left bank. As the hybrid complementary power source, hybrid battery with a two-hour charging time at peak and a capacity of 3.5kWh was considered. When estimating the construction cost of the hybrid micro ...
This study describes the feasibility of anaerobic treatment of complex phenolics mixture from a simulated synthetic coal wastewater using four identical 13.5 L (effective volume) bench scale hybrid up-flow anaerobic sludge blanket (HUASB) (combining UASB + anaerobic filter) reactors at four different hydraulic retention times (HRT) under mesophilic (27 #+-# 5 "oC) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. The phenolics contained phenol (490 mg/L); m-, o-, p-cresols (123.0, 58.6, 42 mg/L); 2,4-, 2,5-, 3,4- and 3,5-dimethyl phenols (6.3, 6.3, 4.4 and 21.3 mg/L) as major phenolic compounds. The study demonstrated that at optimum HRT, 24 h, and phenolic loading rate of 0.75 g COD/(m"3-d), the phenolics and COD removal efficiency of the reactors were 96% and 86%, respectively. Bio-kinetic models were applied to data obtained from experimental studies in ...
This thesis examines the design of a propulsion system for a series hybrid vehicle and includes the study of an energy storage unit using double-layer capacitors and a lightweight soft-switched converter system, and two new components in series hybrid vehicles. The development of environmentally sustainable vehicles is more urgent now given the fact that pollution levels are ever increasing. No electric vehicle has yet been developed that can compete with a normal vehicle based only on internal combustion engines. The dilemma lies in the difficulty of storing the amount of energy needed and supply it a high power levels. An attractive and viable option to reducing pollution and maintaining good performance may lie in hybrid electric-powered vehicles. The double-layer power capacitors are an interesting option because of their high power density and long lifetime. The devices are new and assembling large energy storage units ...
Annona reticulata L. possesses many traits desirable in other edible annonas, and hybridization is the simplest means to combine desirable features of related species. In this study, A. reticulata was hybridized with atemoya (A. cherimola Mill.??A. squamosa L.), and 250 trispecies hybrids were studied for 28 traits (12 tree traits and 16 fruit traits) with the objective of salvaging useful genes from the three edible annonas and determining the extent of variation in the progeny. The heterozygous nature of Annona spp. and simultaneous segregation of three distant genomes resulted in a tremendous heterogeneity in the progenies. The fitness of the progenies ranged from very vigorous to very weak, with a wide range of values for tree height (1.75?5.9?m), canopy spread (1.15?5.07?m) and trunk...
The human smooth muscle myosin heavy chain locus (MYH11) was mapped by fluorescence in situ hybridization to the middle of the p arm of chromosome 16 using a genomic cosmid clone containing coding sequences of the gene as probe. Probe from coding sequence, when applied to Southern blots of a panel of hybrids containing different portions of human chromosome 16, localized the gene to 16p13.13-13.12. Coding sequence PCR primers, when used on the DNA from a CHO-mouse hybrid clone mapping panel informative for mouse chromosomes, showed that the gene was located on mouse chromosome 16. These results correct a recent assignment of MYH11 from 16q12.2 to the region of the 16p-arm inversion breakpoint seen in acute myelomonocytic leukemia (AMML) M4Eo and demonstrate that the conflicting data do not result from the presence of additional MYH genes on the q arm of the chromosome. Also, a new region of conserved synteny between human ...
Study was made on the city bus driven by the series hybrid system composed of a small ceramic gas turbine (100kW), generator and lead storage battery. Two driving modes were adopted, 10-driving mode and real driving mode assuming a certain bus route in Tokyo. The motor is driven mainly by generated power and additionally by battery power, however, the engine/generator system is controlled at an optimum operation point (driving mode and regenerating mode) with a maximum thermal efficiency considering depth of discharge. Design voltage of the battery had nearly no effect on fuel consumption, while its capacity as large as possible was desirable unless its weight has an adverse effect on the system. The real driving mode was lower in fuel consumption by 39% than the 10-driving mode. Since real fuel consumption is largely affected by recovery rate of regenerable energy, the operation point of the motor should be optimized according to driving mode. Fuel consumption at ...
Annex XIII on 'Fuel Cell Vehicles' of the Implementing Agreement Hybrid and Electric Vehicles of the International Energy Agency has been operating since 2006, complementing the ongoing activities on battery and hybrid electric vehicles within this group. This paper provides an overview of the Annex XIII final report for 2010, compiling an up-to-date, neutral, and comprehensive assessment of current trends in fuel cell vehicle technology and related policy. The technological description includes trends in system configuration as well as a review of the most relevant components including the fuel cell stack, batteries, and hydrogen storage. Results from fuel cell vehicle demonstration projects around the world and an overview of the successful implementation of fuel cells in specific transport niche markets will also be discussed. The final section of this report provides a detailed description of national research, ...
The optoelectronic and excitonic properties in a series of linear acenes are investigated using range-separated methods within time-dependent density functional theory (TDDFT). In these highly-conjugated systems, we find that the range-separated formalism provides a substantially improved description of excitation energies compared to conventional hybrid functionals, which surprisingly fail for the various low-lying valence transitions. Moreover, we find that even if the percentage of Hartree-Fock exchange in conventional hybrids is re-optimized to match wavefunction-based CC2 benchmark calculations, they still yield serious errors in excitation energy trends. Based on an analysis of electron-hole transition density matrices, we also show that conventional hybrid functionals overdelocalize excitons and underestimate quasiparticle energy gaps in the acene systems. The results of the present study emphasize the importance of ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered ...
Staggered arrays of dimples printed on opposite surfaces of a cooling channel is formulated numerically and optimized with hybrid multi-objective evolutionary algorithm and Pareto optimal front. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing, and dimple depth, to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-means clustering technique and some of the clustered ...
We report the results of neutron-diffraction experiments on CeM_2Si_2 (M = Ag,Au,Pd,Rh) which were performed to explore the role of valence fluctuations and 4f hybridization in the magnetic ordering of cerium compounds. All four order antiferromagnetically, the first three exhibiting structures consisting of ferromagnetic layers with moments perpendicular to the layers, which are believed to be characteristic of 4f-4f interactions mediated through hybridization with conduction electrons. CePd_2Si_2 has an anomalously small moment (0.62#mu#/sub B/) in the ordered state. CeAg_2Si_2 exhibits an incommensurate longitudinal, static magnetization wave with moment and propagation direction along the a axis. The fourth compound, CeRh_2Si_2, has the highest known transition temperature (39 K) reported for cerium ordering; it exhibits another second-order transition at 27 K to a complex commensurate structure with modulated moments. The results are ...
We report the results of neutron-diffraction experiments on CeM/sub 2/Si/sub 2/ (M = Ag,Au,Pd,Rh) which were performed to explore the role of valence fluctuations and 4f hybridization in the magnetic ordering of cerium compounds. All four order antiferromagnetically, the first three exhibiting structures consisting of ferromagnetic layers with moments perpendicular to the layers, which are believed to be characteristic of 4f-4f interactions mediated through hybridization with conduction electrons. CePd/sub 2/Si/sub 2/ has an anomalously small moment (0.62..mu../sub B/) in the ordered state. CeAg/sub 2/Si/sub 2/ exhibits an incommensurate longitudinal, static magnetization wave with moment and propagation direction along the a axis. The fourth compound, CeRh/sub 2/Si/sub 2/, has the highest known transition temperature (39 K) reported for cerium ordering; it exhibits another second-order transition at 27 K to a complex commensurate structure ...
A new organic-inorganic hybrid membrane has been prepared with exceptional performance in dewatering applications. The only precursor used in the sol-gel synthesis of the selective layer was organically linked 1,2-bis(triethoxysilyl)ethane (BTESE). The microporous structure of this layer enables selective molecular sieving of small molecules from larger ones. In the dehydration of n-butanol with 5% of water, the membrane shows a high separation factor of over 4000 and ultra-fast water transport at a rate of more than 20 kg m{sup -2} h{sup -1} at 150C. This can be related to the high adsorption capacity of the material and the sub-micron thickness of the selective layer. The selectivity has now remained constant over almost one and a half years under continuous process testing conditions. Apart from the hydrothermal stability, the membrane exhibits a high tolerance for acid contamination. A slow performance decline in flux and separation factor is only observed at a ...
The generalized hybrid derivative coupling model has been applied to explore various ground state properties of different nuclei. In this work we have confined our calculation only to the model characterized by the hybridization parameter {alpha} = 1/4 which gives better results than the other models of the same class, as we have seen earlier, for nuclear matter calculations. The binding energy, single-particle energy spectra, density and charge radii of different doubly closed nuclei like {sup 16}O, {sup 40}Ca, {sup 48}Ca, {sup 90}Zr, {sup 132}Sn, {sup 208}Pb have been studied. The success of this model, in describing the doubly closed nuclei, motivates us to extend this calculation further in the case of open shell nuclei after incorporating the pairing interaction and using a BCS transformation. We have calculated the binding energy for such nuclei. We have also studied the isotopic shift for different Pb isotopes with respect to {sup ...
An electrochemical detection method for analyzing sequence-specific DNA using gold nanoparticle DNA probes and subsequent signal amplification step by silver enhancement is described. The assay relies on the electrostatic adsorption of target oligonucleotides onto the sensing surface of the glassy carbon electrode (GCE) and its hybridization to the gold nanoparticle-labeled oligonucleotides DNA probe. After silver deposition onto gold nanoparticles, binding events between probe and target were monitored by the differential pulse voltammetry (DPV) signal of the large number of silver atoms anchored on the hybrids at the electrode surface. The signal intensity difference permits to distinguish between the match of two perfectly matched DNA strands and the near-perfect match where just one base pair was wrong. Coupled with this 'nanoparticle-promoted' reduction of silver signal amplification method, the sensitivity of this ...
In response to the decisions adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (Kyoto conference for the prevention of global warming) of 1997, hybrid vehicles, electric vehicles, and the like are being announced of their completion or placed on the market one after another as low pollution vehicles with CO2 emission to cause global warming reduced. Fuji Electric Co., Ltd., is engaged in the development of a DC-DC converter for hybrid vehicles in cooperation with Nissan Motor Co., Ltd. The product is characterized in (1) that it is small in size and light in weight because a step-down converter and an emergency step-up converter are integrated; (2) that it enjoys a high efficiency rate of 89%; (3) that its service life is long thanks to its design free of aluminum electrolytic capacitors; and (4) that it is provided with various reliability improving features, such as ...
One of the most promising battery types under development for use in both pure electric and hybrid electric vehicles is the lithium-ion battery. These batteries are well on their way to meeting the challenging technical goals that have been set for vehicle batteries. However, they are still far from achieving the current cost goals. The Center for Transportation Research at Argonne National Laboratory undertook a project for the US Department of Energy to estimate the costs of lithium-ion batteries and to project how these costs might change over time, with the aid of research and development. Cost reductions could be expected as the result of material substitution, economies of scale in production, design improvements, and/or development of new material supplies. The most significant contributions to costs are found to be associated with battery materials. For the pure electric vehicle, the battery cost exceeds the cost goal of the US Advanced Battery Consortium ...
This paper introduces a robust searching hybrid evolutionary algorithm to solve the multi-objective Distribution Feeder Reconfiguration (DFR). The main objective of the DFR is to minimize the real power loss, deviation of the nodes' voltage, the number of switching operations, and balance the loads on the feeders. Because of the fact that the objectives are different and no commensurable, it is difficult to solve the problem by conventional approaches that may optimize a single objective. This paper presents a new approach based on norm3 for the DFR problem. In the proposed method, the objective functions are considered as a vector and the aim is to maximize the distance (norm2) between the objective function vector and the worst objective function vector while the constraints are met. Since the proposed DFR is a multi objective and non-differentiable optimization problem, a new hybrid evolutionary algorithm (EA) based on the combination of the ...
Developing safe, reliable, cost-effective, and efficient hydrogen-electricity co-generation systems is an important step in the quest for national energy security and minimized reliance on foreign oil. This project aimed to, through materials research, develop a cost-effective advanced technology cogenerating hydrogen and electricity directly from distributed natural gas and/or coal-derived fuels. This advanced technology was built upon a novel hybrid module composed of solid-oxide fuel-assisted electrolysis cells (SOFECs) and solid-oxide fuel cells (SOFCs), both of which were in planar, anode-supported designs. A SOFEC is an electrochemical device, in which an oxidizable fuel and steam are fed to the anode and cathode, respectively. Steam on the cathode is split into oxygen ions that are transported through an oxygen ion-conducting electrolyte (i.e. YSZ) to oxidize the anode fuel. The dissociated hydrogen and residual steam are exhausted from the SOFEC cathode and ...
We have been piloting web-based multimedia learning modules (MLMs), developed by the Physics Education Research Group at the University of Illinois at Urbana Champaign (UIUC), as a "prelecture assignment" in several introductory physics courses at California State Polytechnic University at Pomona. In this study, we report the results from a controlled study utilizing modules on electricity and magnetism as a part of a blended hybrid-online course. We asked students in the experimental section to view the MLMs prior to attending the face-to-face class, and to make sure this would not result in additional instructional time, we reduced the weekly class time by one-third. We found that despite reduced class time, student-learning outcomes were not hindered; in fact, the implementation of the UIUC MLMs resulted in a positive effect on student performance on conceptual tests and classroom discussion questions. (Contains 4 figures and 1 table.)
The prevention of subscriber churn through customer retention is a core issue of Customer Relationship Management (CRM). By minimizing customer churn a company maximizes its profit. This paper proposes a hybridized architecture to deal with customer retention problems. It does so not only through predicting churn probability but also by proposing retention policies. The architecture works in two modes: learning and usage.In the learning mode, the churn model learner seeks potential associations from the subscriber database. This historical information is used to form a churn model. This mode also calls for a policy model constructor to use the attributes identified in the churn model to divide all `churners' into distinct groups. The policy model constructor is also responsible for develop...
Even the presence of very low concentrations of dyes (1mgL-1) in the effluent is highly visible and is considered aesthetically undesirable. It must be removed from wastewater completely. This study systematically evaluates the performance of adsorption (three kinds of powdered activated carbons), coagulation (AlCl36H2O) and membrane (submerged hollow fiber microfiltration) processes individually in treating two kinds of reactive dyes (Orange 16 and Black 5) and then using a hybrid process with combined coagulation-adsorption-membrane treatment system. Adsorption capacity and kinetics of Orange 16 were much higher and faster than those of Black 5. The dye removal efficiency by coagulation was highly dependent on dye concentration and solution pH. The hybrid process performance was far more...
The plug-in hybrid electric vehicle (PHEV) may offer a potential near term, low-carbon alternative to today's gasoline- and diesel-powered vehicles. A representative vehicle technology that runs on electricity in addition to conventional fuels was introduced into the MIT Emissions Prediction and Policy Analysis (EPPA) model as a perfect substitute for internal combustion engine (ICE-only) vehicles in two likely early-adopting markets, the United States and Japan. We investigate the effect of relative vehicle cost and all-electric range on the timing of PHEV market entry in the presence and absence of an advanced cellulosic biofuels technology and a strong (450ppm) economy-wide carbon constraint. Vehicle cost could be a significant barrier to PHEV entry unless fairly aggressive goals for re...
Positron emission tomography (PET) is the gold standard for non-invasive assessment of myocardial viability and allows accurate detection of coronary artery disease by assessment of myocardial perfusion. Magnetic resonance imaging (MRI) provides high resolution anatomical images that allow accurate evaluation of ventricular structure and function together with detection of myocardial infarction. Potential hybrid PET/MR tomography may potentially facilitate the combination of information from these imaging modalities in cardiology. Furthermore, the combination of anatomical MRI images with the high sensitivity of PET for detecting molecular targets may extent the application of these modalities to the characterization of atherosclerotic plaques and to the evaluation of angiogenetic or stem cell therapies, for example. This article reviews studies using MRI and PET in parallel to compare their performance in cardiac applications together with the potential benefits ...
The hybrid squeeze-film damper bearing with active control is proposed in this paper and the lubricating with couple stress fluid is also taken into consideration. The pressure distribution and the dynamics of a rigid rotor supported by such bearing are studied. A PD (proportional-plus-derivative) controller is used to stabilize the rotor-bearing system. Numerical results show that, due to the nonlinear factors of oil film force, the trajectory of the rotor demonstrates a complex dynamics with rotational speed ratio s. Poincare maps, bifurcation diagrams, and power spectra are used to analyze the behavior of the rotor trajectory in the horizontal and vertical directions under different operating conditions. The maximum Lyapunov exponent and fractal dimension concepts are used to determine ...
Inspired by the recent realizations of quantum dot (QD)-DNA conjugation, we study the spectral density of a magnetic impurity coupled to a mesoscopic semiconducting host. Using a combination of exact diagonalization technique and an analytic approach, we demonstrate that various types of resonances occur according to the relative position of impurity levels (IL) with respect to the host levels (HL). While the usual Coulomb peaks appear when the IL lie inside a band gap, with IL approaching HL and hybridization activated, they shift nonlinearly with the repulsion strength and even undergo splitting for a strong hybridization. When IL merge into HL, multiple resonances of a comblike structure are found along with a parity effect.
The latent heat of evapotranspiration (ET) plays an important role in the assessment of drought severity as one sensitive indicator of land drought status. A simple and accurate method of estimating global ET for the monitoring of global land surface droughts from remote sensing data is essential. The objective of this research is to develop a hybrid ET model by introducing empirical coefficients based on a simple linear two-source land ET model, and to then use this model to calculate the Evaporative Drought Index (EDI) based on the actual estimated ET and the potential ET in order to characterize global surface drought conditions. This is done using the Global Energy and Water Cycle Experiment (GEWEX) Surface Radiation Budget (SRB) products, AVHRR-NDVI products from the Global Inventory ...
Microgel-clay composite particles were prepared by one-step surfactant-free precipitation polymerization. Laponite nanoparticles present in the reaction mixture become encapsulated during the microgel formation process. Microgel-clay composites based on poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate) containing different amount of incorporated clay nanoparticles were synthesized. The clay content was varied from 2 wt% to 18 wt%. The extremely high incorporation efficiency of the clay nanoparticles into microgels was detected. The size of the hybrid microgels was decreased from 700 nm to 100 nm by increase of the clay concentration in the reaction mixture. Obtained hybrid microgels exhibit negative surface charge and excellent colloidal stability. Microgel-clay composite particle...
A new class of low aspect ratio toroidal hybrid stellarators is found using a more general plasma confinement optimization criterion than quasisymmetrization. The plasma current profile and shape of the outer magnetic flux surface are used as control variables to achieve near constancy of the longitudinal invariant J{sup {asterisk}} on internal flux surfaces (quasiomnigeneity), in addition to a number of other desirable physics target properties. A range of compact (small aspect ratio A), low plasma current devices have been found with significantly improved confinement, both for thermal as well as energetic (collisionless) particle components. With reasonable increases in magnetic field and geometric size, such devices can also be scaled to confine 3.5 MeV alpha particle orbits.
A new class of low aspect ratio toroidal hybrid stellarators is found using more general plasma confinement optimization criterion than quasi-symmetrization. The plasma current profile and shape of the outer magnetic flux surface are used as control variables to achieve near constancy of the longitudinal invariant J* on internal flux surfaces (quasi-omnigeneity), in addition to a number of other desirable physics target properties. We find that a range of compact (small aspect ratio A), high {beta} (ratio of thermal energy to magnetic field energy), low plasma current devices exist which have significantly improved confinement both for thermal as well as energetic (collisionless) particle components. With reasonable increases in magnetic field and geometric size, such devices can also be scaled to confine 3.5 MeV alpha particle orbits.
Ultrathin solid polymer electrolyte membranes containing sulfonic ester groups were prepared by polymerization of methyl benzenesulfonate and octamethylcyclotetrasiloxane in a glow discharge plasma. The sulfonic ester groups of the plasma polymer were transformed to lithium sulfonate groups by treatment with lithium iodide. Hybridization of this plasma polymer containing the lithium sulfonate groups with poly(ethylene oxide) (average Mw 300) resulted in the formation of a single lithium ion conductive film. The hybrid polymer electrolyte films were about 1 #mu#m thick, pinhole-free, adherent to various substrates, and showed ionic conductivities at 60 degrees C of the order of 10"- "6 S cm"- "1 (10"2 #OMEGA# cm"2 resistance per unit area of as-prepared solid polymer electrolyte). This material shows promise for electrochemical applications such as all solid-state lithium batteries, sensors, and electrochemical display devices.
We propose a novel surveillance system that uses hybrid camera network. The system contains a panorama camera and PTZ cameras to take the wide range images and face images at high enough resolution for identification tasks. The robust human detection methods include robust background subtraction method (RRC), skin color segmentation and face tracking method. First, the system detects persons from a panorama image, and then the detailed face images are obtained with the PTZ cameras. The PTZ cameras can track the faces using the four directional features and the relaxation matching. In addition, the system has automatic camera position calibration feature. Thus, the user can use the system without any troublesome settings.
The gene encoding the human type I pituitary adenylate cyclase activating polypeptide receptor (ADCYAP1R1) was mapped to chromosome 7 by PCR analysis of genomic DNA from a human/rodent somatic cell hybrid mapping panel. This assignment was confirmed and the gene localized to chromosome band 7p14 by fluorescence in situ hybridization. A yeast artificial chromosome containing ADCYAP1R1 was identified in the CEPH {open_quotes}B{close_quotes} Mega-YAC library. This YAC includes two highly polymorphic dinucleotide repeat sequences that will facilitate genetic studies of the contribution of ADCYAP1R1 in disease states of the central nervous and neuroendocrine systems. 13 refs., 1 fig.
Genetic mapping is approached using the techniques of high resolution fluorescence in situ hybridization (FISH). This technology and the results of its application are designed to rapidly generate whole genome as tool box of expressed sequence to speed the identification of human disease genes. The results of this study are intended to dovetail with and to link the results of existing technologies for creating backbone YAC and genetic maps. In the first eight months, this approach generated 60--80% of the expressed sequence map, the remainder expected to be derived through more long-term, labor-intensive, regional chromosomal gene searches or sequencing. The laboratory has made significant progress in the set-up phase, in mapping fetal and adult brain and other cDNAs, in testing a model system for directly linking genetic and physical maps using FISH with small fragments, in setting up a database, and in establishing the validity and throughput of the system.
The objective of this work was to combine asymmetric somatic hybridization (donor-recipient fusion or gamma fusion) to microprotoplast-mediated chromosome transfer, as a tool to be used for chromosome mapping in Citrus. Swinglea glutinosa micro protoplasts were irradiated either with 50, 70, 100 or 200 gamma rays and fused to cv. Ruby Red grapefruit or Murcott tangor protoplasts. Cell colonies were successfully formed and AFLP analyses confirmed presence of S. glutinosa in both 'Murcott' tangor and 'Ruby Red' grapefruit genomes. (author)
The formation of nanoparticles during the radiation-induced chemical reduction of silver ions, copper ions, and nickel ions in films based on poly(acrylic acid)-poly(ethylenimine) complexes are studied via electron microscopy. This approach allows preparation of composites containing nanoparticles that are randomly distributed in the polymer matrix and materials with a regular spatial distribution of nanoparticles across the film thickness and in subsurface layers. The structure of metal-polymer hybrid materials is dependent on the irradiation conditions, the type of reduced metal ions, and their initial content in polymer matrices. The ratio between the rate of nucleation and the rate of growth of nanoparticles in the matrices of interpolyelectrolyte complexes depends on the intensity of ...
To gain in efficiency, lightness and volume, the hybrid and electric-powered cars will certainly follow the cellular phone path. The key of success of todays hybrid cars is the Ni-MH battery developed by Matsushita (87.5% of the market in 2004). The lithium-ion batteries will be the next step and would allow to supply 80 to 100% of the energy of the vehicle, the thermal engine becoming just an auxiliary system for additional power, autonomy and air-conditioning. Prototypes can reach today 200 to 450 km of autonomy and 130 km/h speeds with batteries of about 200 kg. If most of the safety problems linked with the Li technology have been solved, the main drawback remains the cost of the Li-ion technology. Short paper. (J.S.)
We suggest that \\psi (4040) and \\psi (4160) are strong mixtures of ground state hybrid charmonium at \\sim 4.1 GeV and the \\psi (3S) of conventional charmonium. The \\Gamma^{e^+e^-}, masses and total widths of the \\psi(4040) and \\psi(4160) are in accord with this hypothesis. Their hadronic decays are predicted to be dominated by the \\psi (3S) component and hence are correlated. In particular we find a spin counting relation \\Gamma (4160 \\rightarrow D_sD_s^*) \\sim 4 \\Gamma (4040 \\rightarrow D_sD_s) due to their common \\psi(3S) component. For D and D^* production, using \\psi(4040) branching ratios as input, we predict that the decay pattern of the \\psi(4160) will be very different from that of the \\psi(4040). These predictions may be tested in historical data from SPEAR, BES or at future Tau-Charm Factories.
We determined the chromosomal localization and structure of the gene encoding human type II inosine 5{prime}-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205), an enzyme associated with cellular proliferation, malignant transformation, and differentiation. Using polymerase chain reaction (PCR) primers specific for type II IMPDH, we screened a panel of human-Chinese hamster cell somatic hybrids and a separate deletion panel of chromosome 3 hybrids and localized the gene to 3p21.1{yields}p24.2. Two overlapping yeast artificial chromosome clones containing the full gene for type II IMPDH were isolated and a physical map of 117 kb of human genomic DNA in this region of chromosome 3 was constructed. The gene for type II IMPDH was localized and oriented on this map and found to span no more than 12.5 kb.
A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O40^3^- (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N^+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in ...
The battery size of a Plug-in Hybrid Electric Vehicle (PHEV) is decisive for the electrical range of the vehicle and crucial for the cost-effectiveness of this particular vehicle concept. Based on the energy consumption of a conventional reference car and a PHEV, we introduce a comprehensive total cost of ownership model for the average car user in Germany for both vehicle types. The model takes into account the purchase price, fixed annual costs and variable operating costs. The amortization time of a PHEV also depends on the recharging strategy (once a day, once a night, after each trip), the battery size, and the battery costs. We find that PHEVs with a 4kWh battery and at current lithium-ion battery prices reach the break-even point after about 6 years (5 years when using the lower nig...
This study looks for the presence of rational speculative bubbles in Real Estate Investment Trusts (REITs) using unit-root, variance ratio, duration dependence and regime switching regression tests. The regime switching method provides weak evidence of speculative bubble behaviour in both the mortgage and hybrid REITs sectors even though traditional econometric bubble tests do not provide evidence of rational speculative bubbles in all REIT markets. Findings suggest that price movement in mortgage and hybrid REITs may be induced by bubble-like behaviour of investors. This behaviour may be traced to the real estate market bubble. Our results provide evidence that the real estate bubble that started in early 2000 was transmitted into securitized real estate markets. A regime switching model ...
Identifying gear damage categories, especially for early faults and combined faults, is a challenging task in gear fault diagnosis. This paper proposes a new multidimensional hybrid intelligent diagnosis method to identify different categories and levels of gear damage automatically. In this method, Hilbert transform, wavelet packet transform (WPT) and empirical mode decomposition (EMD) are performed on gear vibration signals to extract additional fault characteristic information. Then, multidimensional feature sets including time-domain, frequency-domain and time-frequency-domain features are generated to reveal gear health conditions. Multiple classifiers based on several classification algorithms and input features are combined with genetic algorithm (GA). Because of the use of multidim...
In this paper, a hybrid time-frequency method (HTM) based on the improved Morlet wavelet and auto terms window (ATW) is presented. The Morlet wavelet, for its shape is similar to the mechanical shock signals, is added two parameters which decide the shape of the mother wavelet. The added parameters and the appropriate scale parameter for continuous wavelet transformation (CWT) are calculated using the cross validation method (CVM) and the minimum Shannon entropy method. The useless noise in the original signal can be filtered by the CWT filter de-noising process. An ATW based on the Smoothed Pseudo Wigner-Ville Distribution (SPWVD) spectrum is designed as a window function to suppress the cross terms in Wigner-Ville Distribution (WVD). The gear fault diagnosis experiment results show that ...
Managing service quality is vital to retain customer satisfaction and augment revenues for any business organization. Often it is difficult to assess service quality due to lack of quantifiable measures and limited data. In this paper, we present a hybrid approach based on SERVQUAL and fuzzy TOPSIS for evaluating service quality of urban transportation systems. The proposed approach consists of three steps. The first step involves development of a SERVQUAL based questionnaire to collect data for measuring transportation service quality. The participants provide linguistic assessments to rate the service quality criteria and the alternatives. In step 2, the linguistic ratings are combined through fuzzy TOPSIS to generate an overall performance score for each alternative. The alternative wit...
Feature selection refers to the problem of selecting relevant features which produce the most predictive outcome. In particular, feature selection task is involved in datasets containing huge number of features. Rough set theory has been one of the most successful methods used for feature selection. However, this method is still not able to find optimal subsets. This paper proposes a new feature selection method based on Rough set theory hybrid with Bee Colony Optimization (BCO) in an attempt to combat this. This proposed work is applied in the medical domain to find the minimal reducts and experimentally compared with the Quick Reduct, Entropy Based Reduct, and other hybrid Rough Set methods such as Genetic Algorithm (GA), Ant Colony Optimization (ACO) and Particle Swarm Optimization (PSO).
The paper describes two schemes that follow the model of Lamarckian evolution and combine differential evolution (DE), which is a population-based stochastic global search method, with the local optimization algorithm of conjugate gradients (CG). In the first, each offspring is fine-tuned by CG before competing with their parents. In the other CG is used to improve both parents and offspring in a manner that is completely seamless for individuals that survive more than one generation. Experiments involved training weights of feed-forward neural networks to solve three synthetic and four real-life problems. In six out of seven cases the DE?CG hybrid, which preserves and uses information on each solution?s local optimization process, outperformed two recent variants of DE.
In recent years, with the development of microarray technique, discovery of useful knowledge from microarray data has become very important. Biclustering is a very useful data mining technique for discovering genes which have similar behavior. In microarray data, several objectives have to be optimized simultaneously and often these objectives are in conflict with each other. A Multi Objective model is capable of solving such problems. Our method proposes a Hybrid algorithm which is based on the Multi Objective Particle Swarm Optimization for discovering biclusters in gene expression data. In our method, we will consider a low level of overlapping amongst the biclusters and try to cover all elements of the gene expression matrix. Experimental results in the bench mark database show a significant improvement in both overlap among biclusters and coverage of elements in the gene expression matrix.
The Time Projection Chamber (TPC) magnet at LBL and its compensation solenoids are adiabatically stable superconducting solenoid magnets. The cryogenic system developed for the TPC magnet is discussed. This system uses forced two-phase tubular cooling with the two cryogens in the system. The liquid helium and liquid nitrogen are delivered through the cooled load by forced tubular flow. The only reservoirs of liquid cryogen exist in the control dewar (for liquid helium) and the conditioner dewar (for liquid nitrogen). The operation o these systems during virtually all phases of system operation are described. Photographs and diagrams of various system components are shown, and cryogenic system data are presented in the following sections: (1) heat leaks into the TPC coil package and the compensation solenoids; (2) heat leaks to various components of the TPC magnet cryogenics system besides the magnets and control dewar; (3) the control dewar and its relationship to ...
The detailed electronic energy band structure of hexagonal close-packed #alpha#-zirconium, corresponding to the atomic configuration of 4d"25s"2 of its four outermost valence electrons, has been computed by the composite-wave variational version of the augmented-plane-wave(APW) method in conjunction with the X#alpha#(#alpha# = 0.70424) exchange approximation for obtaining the potentials. From these data the electronic density of states and its angular-momentum-decomposed components have been obtained by the Raubenheimer-Gilat method. These quantities are required in order to calculate the electron-phonon interaction parameter (lambda) and the superconducting transition temperature (Tsub(c)) within the framework of the theories of Gaspari and Gyorffy and McMillan. A study of the variation of Tsub(c) with the Coulomb pseudopotential (#mu#*) revealed that #mu#* = 0.1 yields the best agreement between theory and experiment for #alpha#-Zr. Also studied from the energy ...
The reactive evaporation process was successfully used to deposit films of the A-15 Nb_3Ge phase. This is the first report, to the best of our knowledge, illustrating the use of such processes for the deposition of A-15 compounds. In this process, niobium vapors from an electron-beam-heated evaporation source react with germane gas introduced into the vacuum chamber at low partial pressures (approximately 10"-"4 Torr) to produce Nb_3Ge deposits. The process variables studied were the deposition temperature, the niobium-to-germanium impingement ratio on the substrate and the plasma-enhanced deposition, in this case the activated reactive evaporation process. At low deposition temperatures (below 450"0C) the deposit is amorphous (or microcrystalline) and can be crystallized to the Nb_3Ge phase by heat treatment, e.g. at 850"0C for 1 h in vacuum. The ratio of niobium to germanium in the deposit can be varied by changing the process parameters. The films are ...
Superconductivity of binary alloys spanning the A-15 compounds V/sub 3/Si, V/sub 3/Ge, V/sub 3/Ga, and V/sub 3/Al and the pseudobinary derivatives of these stoichiometric compounds was surveyed by studying samples prepared by rf-sputtering from alloy cathodes. The possible formation of the hypothetical A-15 binaries ''V/sub 3/P,'' ''V/sub 3/B,'' and ''V/sub 3/C'' and their pseudobinary formation with V/sub 3/Si was also explored. Efforts to form these hypothetical alloys were not successful. The T/sub c/'s were measured resistively and the structure and lattice constants were determined by x-ray analysis. A maximum T/sub c/ of 11.7/sup 0/K was obtained for A-15 V/sub 3/Al, and the importance of a suitable deposition temperature and high sputtering pressures was examined. It is proposed that large variations of T/sub c/ among pseudobinary alloys imply ...
Superconductivity of binary alloys spanning the A-15 compounds V_3Si, V_3Ge, V_3Ga, and V_3Al and the pseudobinary derivatives of these stoichiometric compounds was surveyed by studying samples prepared by rf-sputtering from alloy cathodes. The possible formation of the hypothetical A-15 binaries ''V_3P,'' ''V_3B,'' and ''V_3C'' and their pseudobinary formation with V_3Si was also explored. Efforts to form these hypothetical alloys were not successful. The T/sub c/'s were measured resistively and the structure and lattice constants were determined by x-ray analysis. A maximum T/sub c/ of 11.7"0K was obtained for A-15 V_3Al, and the importance of a suitable deposition temperature and high sputtering pressures was examined. It is proposed that large variations of T/sub c/ among pseudobinary alloys imply a rapid variation of the density of states at the Fermi level.
The stability of a forced-flow cooled superconducting coil is investigated by use of the numerical simulation. The numerical code to integrate the simultaneous partial differential system composed of the 1 D hydrodynamic equations and the 1 D thermal conduction equation has been developed and stability margins are evaluated as functions of coolant mass flow rate, operation current and imposed magnetic field. The results of computations show that the stability margin is multi-valued with respect to these operation parameters, as expected from the experimental results. It is also shown that the appearance of the first unstable regime is closely related to the existance of the stagnant region located at the upstream side of the heated zone and that the second stable regime appears because the heat transfer is appreciably enhanced by the induced backflow due to the thermal expansion of coolant. 13 refs., 13 figs., 1 tab.
The authors introduce the single electron (Cooper-pair) tunneling junctions using c-axis Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+d} (Bi-2212) superconducting single crystal whiskers. Focused-ion-beam (FIB) etching patterned the Bi-2212 whiskers. The fabricated small stacked junctions have in-plane area S smaller than <1 {micro}m{sup 2}. The junctions showed the current-voltage (I-V) characteristics with the periodic structure of current peaks. The stacking layered structure of Bi-2212 works as multi-junctions array which decrease the effective capacitance, C{sub {Sigma}} = C{sub 0}/N, where C{sub 0} is the capacitance of junction and N is the layer number of elementary junctions. The period of current peaks of I-V curves corresponds to the charging energy of the single Cooper pair, 2Ec (=e{sup 2}/C{sub {Sigma}}).
We report the results of a linearized augmented-plane-wave calculation of the electronic structure of fcc La at three lattice constants corresponding to ambient pressure, 50, and 120 kbars. The Kohn-Sham-Gaspar approximation for exchange and correlation is used and the potential is allowed a fully non-muffin-tin form. The f bands lie approx.2--2.5 eV above the Fermi level and are approx.1 eV wide, resulting in a very small (0.05 electrons) localized f occupation. Under pressure the f bands rise and broaden appreciably, resulting in only a slight increase in f occupation. The rigid-muffin-tin approximation for the electron-phonon interaction lambda overestimates the superconducting transition temperature T/sub c/ by 40%, but we find that the drastic increase in T/sub c/ under pressure can be attributed primarily to changes in the electronic stiffness eta. Structural transitions which occur at 25 and 53 kbars may be related to changes in Fermi-surface topology which ...
This work describes the theoretical basis for a new concept rotating magnetic tensor gradiometer. The rotating gradiometer consists of an approximately axial or transverse gradiometer which is made to rotate about a perpendicular axis so that the direction of sensitivity is continually changing. It is demonstrated for the first time that the rotation separates gradient components of progressively higher-order in the frequency domain and enables absolute-value measurements of all components of the first-order magnetic gradient tensor, even if the magnetic sensors comprising the gradiometer are intrinsically incapable of absolute-value detection. In addition, the rotating gradiometer concept has a number of other advantages: the gradiometer imbalance is no longer directly determined by the engineering precision, the DC and low-frequency performance of the instrument is not limited by the performance of the detectors in these respects, rotation at frequencies above the 1/f noise corner of ...
The authors have measured the magnetization of single-phase 90-K superconductors, GdBa_2Cu_3O/sub 6+#delta#/, EuBa_2Cu_3O/sub 6+#delta#/, and SmBa_2Cu_3O/sub 6+#delta#/ with a SQUID magnetometer. They have shown that, in the superconducting state, each magnetization-field curve exhibits a maximum at #approx# 100 G, followed by a linear increase of the magnetization with a slope only approximately one-fifth of the slope for a field smaller than 50 G. They have also investigated the effect of #gamma#-irradiation on YBa_2Cu_3O/sub 6+#delta#/, SmBa_2Cu_3O/sub 6+#delta#/, and have found that the radiation damage results in the appearance of a tail in the superconducting transition. They have also shown that the normal resistance decreases with increasing radiation exposure up to a dose of 10 Mrad.
We analyze the impact of trap states in the oxide layer of a superconducting tunnel junctions, on the fluctuation of the Josephson critical current, thus on coherence in superconducting qubits. Two mechanisms are usually considered: the current blockage due to repulsion at the occupied trap states, and the noise from electrons hopping across a trap. We extend previous studies of noninteracting traps to the case where the traps have on-site electron repulsion inside one ballistic channel. The repulsion not only allows the appropriate temperature dependence of 1/f noise, but also is a control to the coupling between the computational qubit and the spurious two-level systems inside the oxide dielectric. We use second order perturbation theory which allows to obtain analytical formulae for the interacting bound states and spectral weights, limited to small and intermediate repulsions. Remarkably, it still reproduces the main features of the model ...
The effects of neutron irradiation on the superconducting and normal state properties of alloys and compounds are presented. Particular emphasis is placed on the A-15 compounds where the effects of neutron irradiation on Tsub(c), Hsub(c_2), long range order parameter and lattice parameter are described. Large depressions (up to 80%) in Tsub(c) are observed for all the A-15 compounds studied with the exception of Mo_3Os where much smaller decreases in Tsub(c) are seen. Along with the decrease in Tsub(c) and increase in lattice parameter, the degree of long range order, as measured by X-ray and neutron diffraction, decreases. Also presented are the results of isothermal and isochronal anneals up to 900"0C. The unirradiated value of Tsub(c) can be restored by annealing, and for those systems where measurements have been made, recovery of the lattice parameter and order parameter also takes place. The effects observed in irradiated material, together with those ...
Results of our systematic NMR study in high T_c cuprates are reviewed. The antiferromagnetic spin fluctuations (AFSF) decrease in the order of La_1_._8_5Sr_0_._1_5CuO_4. YBa_2Cu_3O_7 and Tl_2Ba_2CuO_6_+_y. 1/T_1 of "6"3Cu in the CuO_2 plane in the normal state follows essentially a Curie-Weiss law at high temperature and T_1T = const. law at low temperature. The temperature dependence of 1/T_1 and the Knight shift together with their impurity effect in the superconducting state strongly suggest d-wave pairing implying the AFSF to be responsible for the occurrence of superconductivity. From the NQR frequency measurement the density of Cu 3d and O 2p holes decreases and increases, respectively, in the order of La, Y and Tl compounds, which is consistent with the change of AFSF. The relation between T_c and #nu#_Q, and their pressure dependence suggest that there exists and optimum value of the ratio of Cu 3d and O 2p hole density to give a ...
The principle and history of free-electron laser (FEL), first evidenced in 1977, the relationship between FEL wavelength and output power, the high-power FEL driven by the superconducting linac, the X-ray FEL by the linac, and the medical use are described. FEL is the vacuum oscillator tube and essentially composed from the high-energy linac, undulator and light-resonator. It utilizes free electrons in the vacuum to generate the beam with wavelength ranging from microwave to gamma ray. The first high-power FEL developed in Japanese Atomic Energy Research Institute (JAERI) is based on the development of superconducting linac for oscillating the highest power beam. In the medical field, applications to excise brain tumors (in US) and to reconstruct experimentally blood vessels in the pig heart (in Gunma University) by lasing and laser coagulator are in progress with examinations to remove intra-vascular cholesterol mass by irradiation of 5.7#mu#m ...
The detailed energy-band structure of hexagonal-close-packed technetium, corresponding to the atomic configuration 4d"55s"2 of its seven outermost valence electrons, has been obtained throughout the Brillouin zone using the composite-wave variational version of the augmented-plane-wave (APW) method in conjunction with the X#alpha# (#alpha# = 0.702 99) exchange approximation for obtaining the potentials. From the band-structure data the electronic density of states (DOS) and the angular-momentum--decomposed DOS were calculated by the accurate Gilat-Raubenheimer method. These quantities were used to calculate the electron-phonon coupling constant and the transition temperature (T/sub c/) using the theories of Gaspari and Gyorffy and of McMillan. Also studied were the Fermi surface and the optical properties of Tc via the imaginary part of the interband dielectric constant for bound electrons, the latter being the first of such a study on Tc to date. The ...
We present results of electronic structure calculations for the intermetallic perovskite Sc3InB with the full-potential KKR-LDA method. Sc3InB is a very promising candidate for a new superconductor (related to 8 K MgCNi3) and can be regarded as a boron-inserted cubic Sc3In, which is a high-pressure allotropic form of the hexagonal weak ferromagnet Sc3In. We predict that cubic Sc3In can also be magnetic, whereas Sc3InB having large DOS in the vicinity of E F exhibits non-magnetic ground state. Estimation of the electron-phonon coupling for Sc3InB gives 1. Furthermore, the effect of vacancies in Sc3InB1-x and antisite disorder in Sc3(In-B) on critical parameters is also discussed using the KKR-CPA method. All theoretical results support the possibility of the superconductivity onset in Sc3InB. Preliminary experimental measurements established the transition temperature close to 4.5 K, with a very abrupt change in susceptibility and a correlated drop of the ...
This report summarizes the work on high field superconducting materials and processes performed at the Materials and Molecular Research Division of the Lawrence Berkeley Laboratory. Two major interrelated focal points characterize this research. One was the decision to restrict the effort to A-15 compounds because of their superior critical temperatures and critical fields. The inherent brittleness of these compounds along with the requirement for a filamentary morphology led to the second focal point: a heavy reliance on a powder approach for the fabrication of superconducting tapes and wires. There have been exceptions to the use of powder techniques where special circumstances such as the nature of a particular alloy system suggested on alternative approach. The quench-age technique described herein is an example of a non-powder approach. Here the niobium-aluminum system is involved and the methodology is based on the fact that in a certain ...
The BESS detector is a new type of balloon-borne spectrometer which utilizes various technologies recently developed for collider experiments. The principal scientific objectives include a measurement of cosmic-ray antiproton spectrum, search for anti-nuclei in cosmic radiation, and precise measurements of cosmic-ray primaries. A thin superconducting solenoidal coil produces a uniform magnetic field of 1 T. Cylindrical drift chambers are located inside and outside the coil and perform continuous tracking. The momentum resolution is 0.5% at 1 GeV/c. i.e., the maximum detectable rigidity is 200 GV. Scintillation counter hodoscopes, placed above and below the solenoid, provide timing and dE/dx measurements and trigger generation. The timing resolution is 80 ps/counter. This cylindrical configuration achieves a large geometrical acceptance of 0.35 m{sup 2} sr which is essential to detect rare cosmic-ray particles. In order to cope with high trigger rate and large data ...
The Magnet Test Facility at Fermilab tests a variety of full-scale and model superconducting magnets for both R and D and production. As the design characteristics and test requirements of these magnets vary widely, the magnet test stand must accommodate a wide range of Data Acquisition (DAQ) and Control requirements. Such a system must provide several functions, which includes: quench detection, quench protection, power supply control, quench characterization, and slow DAQ of temperature, mechanical strain gauge, liquid helium level, etc. The system must also provide cryogenic valve control, process instrumentation monitoring, and process interlock logic associated with the test stand. A DAQ and Control system architecture that provides the functionality described above has been designed, fabricated, and put into operation. This system utilizes a modular approach that provides both extensibility and flexibility. As a result, the complexity of the hardware is ...
A variable-dispersion electron spectrometer is being installed for use by the Stanford Superconducting Accelerator in conjunction with its Free Electron Laser program. The system has been designed to operate with electron beam energies from 20 MeV to 200 MeV, with a maximum energy resolution of 0.01% FWHM. The maximum energy acceptance is approximately #+-# 5%, as determined by the bending magnet aperture. Resolution is controlled by adjusting the focal conditions at the entrance to a 90 degree bending magnet, while the dispersion is controlled by changing the magnitude and polarity of the field in a quadrupole magnet which immediately follows the bending magnet. 4 refs., 5 figs.
For spintronic applications it is important to establish how efficiently spins can be injected from a magnetic material into a non-magnetic material and the distance over which those spins survive. It is thought that spin polarised transport current can be determined by using the suppression of the Andreev reflection between a superconductor and the spin polarised material (Science 282 (1998) 85). Cu/Co bilayers are potentially an ideal test system for such study. In this paper we assess the feasibility of using point contact Andreev reflection spectroscopy to address this problem using a superconducting niobium tip at 4.2 K.
Fourier Transform Infrared (FTIR) spectroscopy has been utilized during high rate E-beam evaporation/deposition of YBa2Cu3O7 (YBCO). The results demonstrate the great utility of FTIR as an in situ monitor of YBCO deposition and processing. We detect different (amorphous/fine polycrystalline) insulating pre-existing phases to the high Tc superconducting phase which appear to have distinct reflectivity fingerprints dominated by thin film interference effects, as a function of temperature and oxygen pressure. These fingerprints reveal some of the kinetic and thermodynamic pathways during the growth of YBCO.
We propose triplet superconductors, such as ruthenates, as prospective materials for qubit construction. The vectorial nature of the order parameter in triplet superconductors makes it conceptually easy to estimate the performance of the qubits. The Cooper condensate of pairs in triplet superconductors has all the attributes of Bose-Einstein condensates and should facilitate long decoherence times for these qubits, relative to other vectorial schemes for qubits, such as small ferromagnets. There are other benefits, which the superconducting state provides for requirements such as entanglement between qubits via the proximity effect, etc. We consider these benefits in detail, although our consideration is only preliminary and further experimental and theoretical research will undoubtedly introduce correctives.
A total of 50 000 tonnes of low-carbon steel sheet has been ordered for the LHC main magnets. After three years of production, about 10 000 tonnes of steel sheet have been produced by Cockerill-Sambre Groupe Usinor. This paper gives a summary of the manufacturing process and improvements implemented as well as an overview of the difficulties encountered during this production. Preliminary statistics obtained for the mechanical and magnetic steel properties are presented. (6 refs).
We studied the niobium re-entrant cavity utilized by the Australian group in the Niobe gravitational wave detector. Instead of using their non-contact re-entrant cavity, we plan to change it to a closed one to be used in the parametric transducers of the Brazilian Mario Schenberg detector. The performance of the transducer depends on some cavity parameters such as the electrical Q and the electrical coupling. We measured the resonant frequency and the loaded electrical Q as a function of the probe position in a closed niobium #approx#15 GHz cavity operating at 4.2 K.
The aim of the report is to describe the state and prospects of the experimental and stand base (ESB) for fundamental investigations in the RF Ministry for Atomic Energy. The ESB includes the following scientific directions: high energy physics, nuclear physics, solid state physics (including superconductivity), plasma physics and controlled thermonuclear synthesis, nuclear reactors and reactor materials testing, lasers, energy conversion and others. Main economical, scientific and technical data on the ESB as a whole and on its most large scientific centers are presented
The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here.
The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building. copyright 1997 American Institute of Physics.
CERN has encouraged the US-LARP collaboration to participate in Phase I of the LHC luminosity upgrade by analyzing the benefits gained by using Nb3Sn technology to replace the functionality of select NbTi magnets that CERN is committed to construct. Early studies have shown that the much higher gradients (shorter magnetic lengths) and temperature margins (quench stability) of Nb3Sn magnets compared to their NbTi counterparts is favorable--allowing the insertion of additional absorbers between Q1 and Q2, for example. This paper discusses the relative merits of the NbTi and Nb3Sn options.
We present a study of the interaction between Josephson junctions in circular superconducting rings and non-classical microwaves, treating both quantum mechanically. A Hamiltonian that describes both inductive and capacitive coupling between the two systems is derived within the external field approximation. Other Hamiltonians which go beyond the external field approximation, and describe explicitly the interaction of the quantum circuit that produces the non-classical microwaves with the Josephson junction circuit, are also presented. A comparison between current experiments which use classical electromagnetic fields and the proposed experiments that use non-classical microwaves, is made. (orig.) With 6 figs., 32 refs.
We propose to encode a register of quantum bits in different collective electron spin wave excitations in a solid medium. Coupling to spins is enabled by locating them in the vicinity of a superconducting transmission line cavity, and making use of their strong collective coupling to the quantized radiation field. The transformation between different spin waves is achieved by applying gradient magnetic fields across the sample, while a Cooper pair box, resonant with the cavity field, may be used to carry out one- and two-qubit gate operations.
In general there are actually two different types of A-15 compounds (A_3B) whose superconducting properties depend on whether the B atoms are transition elements (s-d type) or nontransition elements (s-p type). The properties in which the s-d type superconductors show marked differences in behavior from the s-p type include: (1) stoichiometry and range of composition, (2) the strong influence of N(O) on the stability and T/sub c/ of the phase, and (3), the effect of composition and atomic ordering on the T/sub c/ of the phase. These differences are discussed and a conclusion presented.
It is suggested that the large reduction of the superconducting transition temperature T sub(c) due to defects observed experimentally in some A-15 compounds is caused by smearing of a high peak in the density of states at the Fermi level. The influence of defects on other physical properties (the magnetic susceptibility chi, the elastic modulus C sub(s), the structural transformation temperature T sub(m) and the electrical resistivity rho) is also discussed from the same point of view. We expect the anomalous temperature dependence of chi C sub(s) and rho will be suppressed by defects. (auth.).
The International Linear Collider Main Linacs are based on superconducting accelerator structures operating at 1.3 GHz. The basis for this design has been developed and tested at DESY and R&D is progressing at many laboratories around the world including DESY, Orsay, KEK, FNAL, SLAC, Cornell, and JLAB. The status of the TESLA-style cavities and rf system will be reviewed and parameters for the ILC linac will be described. The role of the different linac test facilities will discussed and the critical items and R&D program to support a Conceptual Design and Technical Design will be outlined.
The existence of a narrow peak in the electronic density of states in A-15 compounds is explained by a strong electron--phonon interaction that leads to the polaron narrowing of the band. An analytic expression relating the transition temperature T/sub c/ to the phonon spectrum is derived under the assumption of a weak and an intermediate-strength coupling. The model allows the explanation of the correlation of T/sub c/ with the number of electrons per atom, the temperature dependence of the resistance, the magnitude and temperature dependence of the magnetic susceptibility, and the electronic specific heat.
We describe the PBAR balloon-borne magnet spectrometer flown on August 13-14, 1987 to measure the abundance of cosmic ray antiprotons in the energy interval 100-1580 MeV at the top of the atmosphere. The limits first reported have been improved to an overall limit of anti p/p<2.0x10{sup -5} (85% CL). We summarize the overall design and performance of the PBAR spectrometer, which had the unique ability to establish the mass of each singly charged cosmic ray, as well as to reject spurious antimatter candidates caused by hard scatterings within the instrument. (orig.).
An accelerator experiment was performed using a low-energy antiproton beam to measure antiproton detection efficiency of BESS, a balloon-borne spectrometer with a superconducting solenoid. Measured efficiencies showed good agreement with calculated ones derived from the BESS Monte Carlo simulation based on GEANT/GHEISHA. With detailed verification of the BESS simulation, the relative systematic error of detection efficiency derived from the BESS simulation has been determined to be {+-}5%, compared with the previous estimation of {+-}15% which was the dominant uncertainty for measurements of cosmic-ray antiproton flux.
In drift tube linacs a beam energy spread results form the finite beam size. Radial variation of the axial accelerating field induces a beam energy spread, which, in general, will accumulate as the beam passes through successive drift tubes. This paper shows that under some conditions of periodic transverse focusing and longitudinal phase focusing, the correlation between the longitudinal and transverse motion can be used to correct the energy spread. The process of achieving such a correction is first described in a simplified situation, and then demonstrated for a particular tuning using a ray-tracing program which models a low velocity and low charge state linac designed for radioactive ion beams.
The Compact Muon Solenoid (CMS) is one of the experiments which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.38 m and the aperture is 6.36 m. This is achieved with a 4 layer-5 module superconducting Al-stabilized coil energised at a nominal current of 20 kA. The finite element analysis (FEA) carried out is axisymmetric elasto-plastic. FEA has also been carried out on the suspension system and on the conductor. (8 refs).
We review 25 specific heat measurements performed in Geneva on binary and pseudo-binary A-15 compounds. The rather extended temperature range allows us to make reliable estimates of several moments of the phonon spectrum which are required in the theory of superconductivity. The Tsub(c) expression of Allen and Dynes can then be used consistently to estimate the microscopic parameters lambda, eta, Nsub(bs) (Esub(F)), etc. The broad range of values reviewed permits to establish significant correlations between the parameters in stoichiometric and ordered compounds. (orig.).
The homogeneity of the magnetic field in the LHC dipoles strongly depends on the correct position of the superconducting cables: this is related to the quality of the dipole components, such as the dimension of the coil spacers (copper wedges), of the cable and of the collars. The performance in operational conditions is also affected by the magnetization of the cables. In this work, we analyse the measurements of these quantities during the production of the 1276 LHC dipoles, their trends, and the relation to the measured magnetic field. A novel mtehod to locate electrical shorts based on the analysis of magnetic measurements is also presented, and applications to 15 dipoles reascued during the production is given.
High energy ion backscattering analysis in combination with recently-developed resonance scattering analysis is described, with a stress on precise and quantitative oxygen analysis and its successful application to the characterization and quality estimation of high T_c oxide superconductors. Particularly, the present status of high energy ion backscattering analysis, the review of analytical results for YBa_2Cu_3O_7 _- _x, the estimation of composition and crystalline quality of (La_1 _- _xSr_x)_2CuO_4 by 7 MeV alpha particle backscattering analysis are described.
The preliminary design of the read-out system for the GEM (Gammas, Electrons, Muons) detector at the Superconducting Super Collider is presented. The system reads all digitized data from the detector data sources at a Level 1 trigger rate of up to 100 kHz. A total read-out bandwidth of 40 GBytes/s is available. Data are stored in buffers that are accessible for further event filtering by an on-line, processor farm. Data are transported to the farm only as they are needed by the higher-level trigger algorithms, leading to a reduced bandwidth requirement in the Data Acquisition System.
The effect of yttrium substitution at the lanthanum site on the superconducting properties of La_1_-_xY_xO_0_._9F_0_._1FeAs ('x' = 0, 0.10, 0.20, 0.30, 0.50 and 0.60) oxypnictides has been studied. Powder X-ray diffraction studies confirm single phases till x = 0.1 beyond which minor amount of Y_2O_3 is observed. The temperature dependence of resistivity measurements confirm the superconducting transition temperature (T_c) of 34.8 (#+-#0.05) K and corresponding Meissner transition at 34.3 K in the 'x' = 0.3 composition which is higher than that reported for the parent phase (LaO_0_._9F_0_._1FeAs (T_c = 28 K)). Further increase in the concentration of yttrium leads to broadening and suppression of the superconducting transition. The value of H_c_2 at zero temperature is estimated to be about 60.5 T. The Seebeck coefficient (S) shows a negative sign indicating that the major contribution to the conductivity is by electrons. ...
The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi_2B_2C and LuNi_2B_2C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi_2B_2C and LuNi_2B_2C single-crystal samples exhibit large transverse magnetoresistance (#approx#6 8% at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T_c. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between #approx#150 K and RT. Extrapolation to T=0 gives large intercepts (few #mu#V/K) for both samples suggesting the presence of a much larger knee than would be expected from electron-phonon interaction renormalization effects. The upper ...
The electronic structure and properties of the cubic Laves phase (C15) compounds ZrZn_2 and ZrV_2 have been determined using our all-electron full-potential linearized-augmented-plane-wave (FLAPW) method for bulk solids. The computations were performed in two stages: (i) self-consistent warped muffin tin and (ii) self-consistent full potential. Spin-orbit coupling was included after either stage. The effects of the inclusion of the nonspherical terms inside the muffin tins on the eigenvalues is found to be small (of order 1 mRy). However, due to the fact that some of the bands near the Fermi level are flat, this effect leads to a much higher value of the density of states at E/sub F/ in ZnZr_2. The most important difference between the materials ZrZn_2 and ZrV_2 is the position of the d bands derived from the Zr and V atoms. Consequently, these materials have completely different Fermi surfaces. We have investigated the magnetic properties of these compounds by evaluating their ...
The electronic structure and properties of the cubic Laves phase (C15) compounds ZrZn/sub 2/ and ZrV/sub 2/ have been determined using our all-electron full-potential linearized-augmented-plane-wave (FLAPW) method for bulk solids. The computations were performed in two stages: (i) self-consistent warped muffin tin and (ii) self-consistent full potential. Spin-orbit coupling was included after either stage. The effects of the inclusion of the nonspherical terms inside the muffin tins on the eigenvalues is found to be small (of order 1 mRy). However, due to the fact that some of the bands near the Fermi level are flat, this effect leads to a much higher value of the density of states at E/sub F/ in ZnZr/sub 2/. The most important difference between the materials ZrZn/sub 2/ and ZrV/sub 2/ is the position of the d bands derived from the Zr and V atoms. Consequently, these materials have completely different Fermi surfaces. We have investigated the magnetic properties of these compounds by ...
High quality La/sub 1.8/Sr/sub 0.2/CuO/sub 4/ and YBa/sub 2/Cu/sub 3/O/sub 7/ superconducting thin films, with zero resistance at 88 K, have been made by dual-ion-beam sputtering of metal and oxide targets at elevated temperatures. The films are about 1.0 ..mu..m thick and are single phase after annealing. The substrates investigated are Nd-YAP, MgO, SrF/sub 2/, Si, CaF/sub 2/, ZrO/sub 2/-9% Y/sub 2/O/sub 3/, BaF/sub 2/, Al/sub 2/O/sub 3/, and SrTiO/sub 3/. Characterization of the films was carried out using Rutherford backscattering spectroscopy, resistivity measurements, transmission electron microscopy, x-ray diffraction, and secondary ion mass spectroscopy. Substrate/film interaction was observed in every case. This generally involves diffusion of the substrate into the film, which is accompanied by, for example, the replacement of Ba by Sr in the YBa/sub 2/Cu/sub 2/O/sub 7/ structure, in the case of SrTiO/sub 3/ substrate. The best substrates were those that ...
The single-axis portion of a three-axis superconducting gravity gradiometer has been completed in the course of this research. The theory of the superconducting gravity gradiometer has been generalized and put into a Lagrangian formulation. A condition for frequency-independent common mode balance combined with a multi-stage vibration isolation scheme has enabled a stable operation of the gradiometer for prolonged periods. In a preliminary test, the gradiometer has exhibited a noise level of 1-2 E Hz"-/sup 1/2/ below 1 Hz, limited by seismic noise, where 1 E = 10"-"9 m s"-"2 m"-"1. To perform a test of the inverse square law, the single-axis gradiometer is mounted with its axis tilted from the vertial by an angle tan"-"1 #sq root#2. The device is then turned incrementally by 120"0 around the vertical to carry the gradiometer from one axis to the other two axes of an orthogonal coordinate system. A lead pendulum weighing 1600 kg forms a periodic ...
Microfabrication processes for Y-Ba-Cu-O films have been investigated, using ion-beam techniques. High-{Tc} superconducting lines as narrow as 0.8 {mu}m have been fabricated from epitaxial YBa{sub 2}Cu{sub 3}O{sub 7 {minus} {ital y}} films by Ar ion-beam etching (IBE), combined with focused ion-beam (FIB) lithography. The resulting lines, 1.3 {mu}m wide and 2 mm long, showed a zero resistance temperature of 81 K and a critical current density of 1.9 {times} 10{sup 4} A/cm{sup 2} at 77.3 K. Maskless etching was carried out using 130-keV au{sup +} focused ion-beam (FIB) with a 0.1-{mu}m-diameter beam. A 50-nm-thick film was patterned into 0.3-{mu}m-wide lines at a dose of 5 {times} {sup 16} ions/cm{sup 2}. In comparison with Ar IBE, Cl{sub 2} reactive ion-beam etching (RIBE) exhibited an enhancement effect in sputtering yield. Ion implantation with 300-keV Si{sup + +} FIB also indicated the possibility to produce submicrometer patterns by selectively modifying film ...
Superconducting generators for high power applications have been of interest for a number of years. Superconducting generators using low temperature superconductors (LTS) have been manufactured to produce up to 20 MW of electrical power and have been configured in either synchronous alternators which have an AC output that may be subsequently rectified to produce DC and homopolar generators which produce low voltage DC. Typically these generators require scrupulous attention to vacuum integrity for cryogenic insulation at 4.2K and tend to be somewhat fragile because of extensive thermal and magnetic shields that are not required in conventional power generators. Recently, high purity aluminum composites have been developed for a high power AC generator that is cooled by cryogenic hydrogen at 21K. This aluminum generator is very compact and lightweight and is much more robust than a generator made with LTS because extensive thermal and magnetic ...
As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low ...
We have investigated the growth behaviors of high temperature compatible ZrO_2 insulation coatings on Ag and AgMg sheathed Bi_2Sr_2Ca_1Cu_2O_x superconducting tapes depending on number of dipping and thermal conditions. The coatings were fabricated on long-length superconducting tape substrates using a solution derived from Zr tetrabutoxide, solvent and chelating agent for high magnetic field magnets. The layer-on-layer growth behaviors were characterized by environmental scanning electron microscope (ESEM), energy dispersive spectroscopy (EDS), X-ray maps and X-ray diffraction (XRD). This research showed that the ZrO_2 coatings were regularly grown on Ag-based tape substrates and coating thickness increased with increasing number of dipping. It was found that ceramic oxides formed at temperature range 450 and 550 deg. C. The final coating thickness changed between 6 and 8 #mu#m after annealing process. Resistance of insulation measured from ...
Research highlights: #-># Red mud residues (RM) were disposed in alumina production. #-># Utilization of Red mud residues was affected by its iron content. #-># Superconducting magnetic separation (HGSMS) was used in iron separation from RM. #-># RM with high and low iron contents were separated in HGSMS. - Abstract: The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (<100 #mu#m) into high iron content part and low iron content part. Two sorts of RM were fed in the HGSMS. The iron oxide contents in concentrates were about 65% and 45% when RM 1 and RM 2 were fed respectively. Meanwhile, the residues contained 52.0% or 14.1% iron oxide in residues after eight separation stages when RM 1 and RM 2 were fed ...
We review the current status of Andreev reflection spectroscopy on the heavy fermions, mostly focusing on the case of CeCoIn5, a heavy-fermion superconductor with a critical temperature of 2.3 K. This is a well-established technique to investigate superconducting order parameters via measurements of the differential conductance from nanoscale metallic junctions. Andreev reflection is clearly observed in CeCoIn5 as in other heavy-fermion superconductors. Considering the large mismatch in Fermi velocities, this observation seemingly appears to disagree with the Blonder-Tinkham-Klapwijk (BTK) theory. The measured Andreev signal is highly reduced to the order of maximum ?13% compared to the theoretically predicted value (100%). The background conductance exhibits a systematic evolution in its asymmetry over a wide temperature range from above the heavy-fermion coherence temperature down to well below the superconducting transition temperature. ...
... Another solution, hybrid vehicles, combine two sources of energy (electric and chemical), reducing the global consumption of fossil fuels. Fuel cell vehicles are also one of the most promising technologies for the future, with the capacity to use any fuel - hydrogen being the ideal fuel ecologically, but constrained by infrastructure and storage issues. This book explores all these different solutions for moving our vehicles from fossil ...
Research highlights: {yields} The use of resonant photoemission in its 'core-hole clock' expression for the study of the dynamical charge transfer across hybrid organic-inorganic interfaces and for the intermolecular charge transfer in the bulk of organic thin films is reviewed. {yields} The electronic coupling to the substrate and the efficiency of charge transport across hybrid interfaces is different for individual electronic subsystems of the molecular adsorbate. {yields} The intermolecular charge transfer in the bulk of discotic liquid crystals occurs on the order of a few femtoseconds and is faster than expected from the macroscopic charge transport characteristics of the material. -- Abstract: The focus of this brief review is the use of resonant photoemission in its 'core-hole clock' expression for the study of two important problems relevant for the field of organic electronics: the dynamical charge ...
Transcription for a hybrid SV40 promoter-beta globin coding sequence recombinant initiates from both early-early (EE) and late-early (LE) SV40 start sites (EES and LES) in the absence of DNA replication....Full Text Available
Toyota's introduction of a hybrid electric vehicle (HEV) named ''Prius'' in Japan and Honda's proposed introduction of an HEV in the United States have generated considerable interest in the long-term viability of such fuel-efficient vehicles. A performance and cost projection model developed entirely at Argonne National Laboratory (ANL) is used here to estimate costs. ANL staff developed fuel economy estimates by extending conventional vehicle (CV) modeling done primarily under the National Cooperative Highway Research Program. Together, these estimates are employed to analyze dollar costs vs. benefits of two of many possible HEV technologies. We project incremental costs and fuel savings for a Prius-type low-performance hybrid (14.3 seconds zero to 60 mph acceleration, 260 time) and a higher-performance ''mild'' hybrid vehicle, or ...
Ultrasound tomography is an attractive imaging method for the detection of breast cancer. The complex anatomy of the breast with its different spatial scales and material property contrasts make accurate reconstructions very challenging. This paper proposes a hybrid approach whereby Travel-of-Flight and Diffraction Tomography are combined together to achieve high-resolution and high-accuracy sound-speed reconstructions. The method is validated with several numerical phantoms.
This article describes the state-of-the-art HVAC system at the Philadelphia Marriott Hotel. Thermal comfort and indoor air quality are emphasized. The system uses a hybrid gas absorption/electric centrifugal chilled water plant, variable flow pumping, water-side economizers to provide free cooling, central air handling units with air-side economizers and flow monitoring equipment.
With the aim of an experimental check on the validity of the theory of molecular recognition, the authors have carried out the chemical-enzymatic synthesis and cloning of the gene of human calcitonin and also of the genes of antisense polypeptides to human calcitonin and miniproinsulin. It has been shown that recombinant plasmids obtained on the basis of these synthetic genes are capable of ensuring the biosynthesis of the given polypeptides in E. coli cells as hybrid proteins with the IgG-binding domain of staphylococcal protein A.
The aim of the study was to establish by means of a measuring programme how much energy for space heating can be saved by the installed hybrid system. Further, experience with the systems was to be gathered under practical use conditions. As user behaviour can influence space heating energy consumption to an extent having several times the effect of the contribution of the hybrid system, a fact that is also reported in literature, it is not sufficient to measure only space heating energy consumption. So, a unit in one of the terraced houses was scrupulously measured. In the three other terraced houses, only space heating energy consumption was measured.- This final report contains not only a description of the concepts of the buildings and hybrid system but also the energy consumptions measured, and detailed analyses of the budgets. (orig./AKF) [Deutsch] Mit Hilfe eines Messprogrammes sollte ermittelt werden, welche ...
The feasibility of performing a multiplex assay for the detection of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) RNAs and hepatitis B virus (HBV) DNA is demonstrated. This...Full Text Available
Lawrence Livermore, Sandia Livermore and Los Alamos National Laboratories have a joint project to develop an optimized hydrogen fueled engine for series hybrid automobiles. The major divisions of responsibility are: system analysis, engine design and kinetics modeling by LLNL; performance and emission testing, and friction reduction by SNL; computational fluid mechanics and combustion modeling by LANL. This project is a component of the Department of Energy, Office of Utility Technology, National Hydrogen Program. We report here on the progress on system analysis and preliminary engine testing. We have done system studies of series hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. The impact of various on-board storage options on fuel economy are evaluated. Experiments with an ...
Lawrence Livermore, Sandia Livermore and Los Alamos National Laboratories have a joint project to develop an optimized hydrogen fueled engine for series hybrid automobiles. The major divisions of responsibility are: system analysis, engine design and kinetics modeling by LLNL; performance and emission testing, and friction reduction by SNL; computational fluid mechanics and combustion modeling by LANL. This project is a component of the Department of Energy, Office of Utility Technology, National Hydrogen Program. We report here on the progress on system analysis and preliminary engine testing. We have done system studies of series hybrid automobiles that approach the PNGV design goal of 34 km/liter (80 mpg), for 384 km (240 mi) and 608 km (380 mi) ranges. Our results indicate that such a vehicle appears feasible using an optimized hydrogen engine. The impact of various on-board storage options on fuel economy are evaluated. Experiments with an ...
This report discusses the following topics: Fusion-fission in light nuclear systems; High-resolution Q-value measurement for the {sup 24}Mg+{sup 24}Mg reaction; Heavy-ion reactions and limits to fusion; and Hybrid MWPC-Bragg curve detector development.
This paper reports the cloning and sequencing of a quail homeobox-containing gene, Quox-1, and its expression pattern in embryos from 3 to 6 days (E3 to E6) of development as determined by in situ hybridization....Full Text Available
This paper reviewed the current status of basic research in plant cell engineering, highlighted the application of embryo culture, double haploid (DH) technology, protoplast culture and somatic hybridization, somaclonal variation, rapid propagation, and bio-products production of plant-origin, and t he prospects. (authors)
Olive oil mill wastewaters (OMW) cause disposal problems because they contain powerful pollutants such as phenolic compounds. Complete biodegradation or removal of these compounds is hardly achieved by a single treatment method. In this work, we investigated 2 integrated technologies for the treatment of the recalcitrant contaminants of OMW, allowing water recovery and reuse for agricultural purposes. (Author)
The physics and technology of a new class of efficient composite piezoelectrics are described. This material combines nanostructured and micropiezoelectric matrix composites. They consist of a polymer matrix, an insulating nanodimensional phase, and a microdimensional piezoelectric phase. It is shown that the nanostructuring of the near-surface region of polymer-PZT piezoelectric composites greatly improves their piezoelectric, mechanical, and electromechanical characteristics. A plausible mechanism underlying this effect is suggested.
Chapter 5, describes some of the most important molecular methods used in the study of chromosome structure and function. The methods discussed include fragmentation of DNA, cloning, flow cytometry and chromosome sorting, is situ hybridization, polymerase chain reaction (PCR), and yeast artificial chromosomes (YACs). 18 refs., 3 figs., 1 tab.
High molecular weight DNA from pleroceroid larvae of the tapeworm Spirometra mansonoides was purified from isolated nuclei by conventional techniques. The DNA so isolated has a melting temperature (Tm) of 87 degrees C and a guanine plus cytosine (G/C) content of 44%. 5-Methyl cytosine could not be detected in plerocercoid DNA by HPLC analysis of DNA hydrolysates, by radiolabeling 5'-termini of MspI digests with polynucleotide kinase, or by comparing restriction patterns generated by MspI and HpaII. Renaturation kinetics demonstrated that the genome of S. mansonoides contains repetitive as well as single copy sequences and has a genome size estimated at approx. 1.6 X 10(9) bp. Hybridization was carried out between plerocercoid DNA and cDNAs for human beta-actin, alpha-tubulin and growth hormone (hGH). Rationale for this analysis was based on known homologies among actin and tubulin genes in numerous species and on apparent similarities between hGH and a plerocercoid ...
The invention relates to a pulsed laser ablation method of metals and/or dielectric films from the surface of a wafer, printed circuit board or a hybrid substrate. By utilizing a high-energy ultra-short pulses of laser light, such a method can be used to manufacture electronic circuits and/or electro-mechanical assemblies without affecting the material adjacent to the ablation zone.
The clinical feasibility of using interventional examination techniques was tested with an equipment combining fluoroscopy and MR imaging. This hybrid system showed to be of advantage in a great number of interventional examinations. The 1.5 Tesla magnet proved to be superior to open MR scanning systems in terms of image quality and scanning times. (orig.).
Some 43 papers were presented in 4 sections: Organ and bud culture of tree species (24 papers); Cell suspension and callus culture of tree species (11); Culture of haploid tissue of tree species and production of wood homozygotes (3); and Isolation, culture and somatic fusion of protoplasts as a means of somatic hybridization and genetic engineering (5).
The hyperfine interactions at the uranium site in the antiferromagnetic USb2 compound were calculated within the density functional theory (DFT) employing augmented plane wave plus local orbital (APW+lo) method. We investigated the dependence of the nuclear quadruple interaction to the magnetic structure in USb2 compound. The result shows that the 5f-electrons have the tendency to be hybridized with the conduction electrons.
The physical layout of the Time-Of-Flight spectrometer at the new spallation source SINQ is presented. The concept shows up a hybrid-TOF combining a Fermi-chopper with a crystal monochromator. The demand of a versatile and flexible instrument for several applications is taken into account by the option of switching from time-focusing to monochromatic focusing mode such that the spectrometer can be optimised for both quasielastic and inelastic scattering applications. (author) 5 figs., 2 tabs., 16 refs.
DescriptionEnzymes are natural catalysts that are used increasingly to replace environmentally harmful chemicals and to achieve better catalytic selectivity during pulp and paper processing. The main objective of this project is to identify novel plant enzymes for deeper understanding of the process of fibre formation and for future improvement of the quality parameters of wood fibres. Specific modification of the fibre characteristics will facilitate their use as raw materials for the current pulp and pap [continued...
By revisiting previous definitions, we show that one can define an energy current operator that satisfies the continuity equation for a general Hamiltonian in one dimension. This expression is useful for studying electronic, phononic and photonic energy flow in linear systems and in hybrid structures. The definition allows us to deduce the necessary conditions that result in current conservation for general-statistics systems. The discrete form of the Fourier's law of heat conduction naturally emerges in the present definition.
The intention of the research carried out was to develop photovoltaic driven solar heating systems applied for drying of medicinal plants in remote areas. Identification of hybrid photovoltaic - photothermal systems was done and discussion of technical features and applicability of such systems in agriculture is presented. Detail technical specification of PV powered medicinal plants solar dryer and cost effectiveness parameters are given. Operational and economic results obtained during testing of the dryer are promising. (orig.) 4 refs.
Currently, over 30,000 mapped STSs and 27,000 mapped Unigenes (non-redundant, unigene sets of cDNA representing EST clusters) are available for human alone. A total of 44,000 Unigene cDNA clones have been supplied by Research Genetics. Unigenes, or cDNAs are excellent resource for map building for two reasons. Firstly, they exist in two alternative forms -- as both sequence information for PCR primer pairs, and cDNA clones -- thus making library screening by colony hybridization as well as pooled library PCR possible. The authors have developed an efficient and robust procedure to screen genomic libraries with large number of DNA probes. Secondly, the linkage and order of expressed sequences, or genes are highly conserved among human, mouse and other mammalian species. Therefore, mapping with cDNA markers rather than random anonymous STSs will greatly facilitate comparative, evolutionary studies as well as physical map building. They have currently deconvoluted ...
This demonstration project uses modern simulation techniques to illustrate the important technologies and design variables that an auto-designer would consider in production a high efficiency, low emissions vehicle. Simulation and modeling techniques use the idea of capturing the relationships between real components of the systems with mathematical equations. These equations are then solved on a computer to simulate the behavior or performance of the system under various conditions. In the current demonstration project, we focus on many variations of a hydrogen-powered vehicle.
DNA from 48 hr germinated rice embryos was cut with restriction endonuclease Bam H1 and cloned to the Bam H1 site on plasmid pBR 322. The clones containing recombinant DNA were selected by their sensitivity to tetracycline and resistance to ampicillin. Using /sup 32/P-labelled rice embryos tRNA as a probe two clones were identified to contain tRNA genes by colony hybridization.
This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system. Taken as a whole, they confirm significant progress towards the technical ...
The chromosomal region 17q12-q21 contains a gene (BRCA1) conferring susceptibility to early-onset familial breast and ovarian cancer. An 8000-rad radiation-reduced hybrid (RH) panel was constructed to provide a resource for long-range mapping of this region. A large fraction of the hybrids ([approximately]90%) retained detectable human chromosome 17 sequences. The complete panel of 76 hybrids was scored for the presence or absence of 22 markers from this chromosomal region, including 14 cloned genes, seven microsatellite repeats, and one anonymous DNA segment. Statistical analysis of the marker retention data employing multipoint methods provided both comprehensive and framework maps of this chromosomal region, including distance estimates between adjacent markers. The comprehensive RH map includes 17 loci and spans 179 cRays[sub (8000)]. Likelihood ratios of at least 1000:1 support the 10-locus framework order: ...
Observed 7-eV satellites in the XPS spectra of UGa_2 and other B-group compounds are shown to be due to two-hole final states as confirmed by existing Auger data. The presence of these satellites is an indication for a weak fd hybridization and, when compared to uranium--transition-metal compounds, increased 5f localization.
The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C single-crystal samples exhibit large transverse magnetoresistance ({approx}6{endash}8{percent} at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T{sub c}. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between {approx}150 K and RT. Extrapolation to T=0 gives large intercepts (few {mu}V/K) for both samples suggesting the presence of a much larger {open_quotes}knee{close_quotes} than ...
The structural ordering of oxygen deficient and Co-doped YBCO (YBa_2Cu_3_-_yCo_yO_6_+_x) have been studied experimentally, and by computer simulations of the oxygen ordering in the basal plane of the structure. The calculations are based on the two-dimensional ASYNNNI model and its modifications. Good agreement is established between the ASYNNNI calculations and the experimentally observed structural properties of the double cell ortho-II structure and the oxygen disordering process from Co-doping into the basal plane. A model that relates the superconducting transition temperature T_c(x) of undoped YBCO and T_c(y) of Co-doped YBCO to the formation of specific domains of the two orthorhombic ordered oxygen phases, ortho-I and ortho-II, shows a close agreement with experimental T_c(x) and T_c(y) data of samples prepared under equilibrium conditions. The structural changes as a result of metal ion substitutions and oxidation/reduction processes have been studied by ...
The radiosensitivity of spermatogonial stem cells of C3H/HeHx101/H F[sub 1] hybrid mice was determined by counting undifferentiated spermatogonia at 10 days after X-irradiation. During the spermatogenic cycle, differences in radiosensitivity were found, which were correlated with the proliferative activity of the spermatogonial stem cells. In stage VIII[sub irr], during quiescence, the spermatogonial stem cells were most radiosensitive with a D[sub 0] of 1.4 Gy. In stages XI[sub irr]-V[sub irr], when the cells were proliferatively active, the D[sub 0] was about 2.6 Gy. Based on the D[sub 0] values for sensitive and resistant spermatogonia and on the D[sub 0] for the total population, a ratio of 45:55% of sensitive to resistant spermatogonial stem cells was estimated for cell killing. When the present data were compared with data on translocation induction obtained in mice of the same genotype, a close fit was obtained when the translocation yield (Y; in % abnormal ...
The investigated hybrid nanocomposite consists of a porous silicon template with electrochemically embedded Ni or Co nanostructures and offers magnetic characteristics which can be tailored by the electrochemical process parameters during fabrication. A twofold magnetic behaviour can be observed, a first one due to the spinmagnetism at magnetic fields below the saturation magnetization of the deposited metals and a second non-saturating term at higher fields (>1 T up to 7 T) above the saturation magnetization. In case of Ni deposited within the pores this non-saturating term shows a paramagnetic characteristic and follows exactly the Curie-Weiss law, whereas for Co/porous silicon samples the temperature dependent magnetization shows some deviations from the Curie Weiss law. In this high field region a difference in the temperature dependence between Ni and Co is observed whereas the non-saturating term does not depend on the geometry of the embedded ...
Evolutionary artificial neural networks (EANNs) refer to a special class of artificial neural networks (ANNs) in which evolution is another fundamental form of adaptation in addition to learning. Evolutionary algorithms are used to adapt the connection weights, network architecture and learning algorithms according to the problem environment. Even though evolutionary algorithms are well known as efficient global search algorithms, very often they miss the best local solutions in the complex solution space. In this paper, we propose a hybrid meta-heuristic learning approach combining evolutionary learning and local search methods (using 1st and 2nd order error information) to improve the learning and faster convergence obtained using a direct evolutionary approach. The proposed technique is tested on three different chaotic time series and the test results are compared with some popular neuro-fuzzy systems and a recently developed cutting angle method of global ...
A push for electric vehicles has occurred in the past several decades due to various concerns about air pollution and the contribution of emissions to global climate change. Although electric cars and buses have been the focus of much of electric vehicle development, smaller vehicles are used extensively for transportation and utility purposes in many countries. In order to explore the viability of fuel cell - battery hybrid electric vehicles, empirical fuel cell system data has been incorporated into the NREL's vehicle design and simulation tool, ADVISOR (ADvanced Vehicle SimulatOR), to predict the performance of a low-speed, fuel cell - battery electric vehicle through MATLAB Simulink. The modelling and simulation provide valuable feedback to the design optimization of the fuel cell power system. A sampling based optimization algorithm was used to explore the viability and options of a low cost design for urban use. (author)
[alpha]-Melanocyte stimulating hormone ([alpha]-MSH), a hormone originally named for its ability to regulate pigmentation of melanocytes, is a 13-amino-acid post-translational product of the pro-opiomelanocortin (POMC) gene. [alpha]-MSH and the other products of POMC processing, which share the core heptapeptide amino acid sequence Met-Glu (Gly)-His-Phe-Arg-Trp-Gly (Asp), the adrenocorticotropic hormone (ACTH), [beta]-MSH, and [gamma]-MSH, are collectively referred to as melanocortins. While best known for their effects on the melanocyte (pigmentation) and adrenal cortical cells (steroidogenesis), melanocortins have been postulated to function in diverse activities, including enhancement of learning and memory, control of the cardiovascular system, analgesia, thermoregulation, immunomodulation, parturition, and neurotrophism. To identify the chromosomal band encoding the human melanocortin-1 receptor gene, 1 [mu]g of an EMBL clone coding region of the human MC1R and approximately 15 kb ...
The product of the human GRO gene is a cytokine with inflammatory and growth-regulatory properties; GRO is also called MGSA for melanoma growth-stimulatory activity. The authors have identified two additional genes, GRO#beta# and GRO#gamma#, that share 90% and 86% identity at the deduced amino acid level with the original GRO#alpha# isolate. One amino acid substitution of proline in GRO#alpha# by leucine in GRO#beta# and GRO#gamma# leads to a large predicted change in protein conformation. Significant differences also exist in the 3' untranslated region, including different numbers of ATTTA repeats associated with mRNA instability. A 122-base-pair region in the 3' region is conserved among the three GRO genes, and a part of it is also conserved in the Chinese hamster genome, suggesting a role in regulation. DNA hybridization with oligonucleotide probes and partial sequence analysis of the genomic clones confirm that the three forms are derived from related but ...
In 1983, the first modern urban transit bus powered by an alternative transportation fuel took to the roads in the USA. A little more than a decade later, about 2.5% of all USA buses are powered by alternative transportation fuels and about 20% of the new bus orders for delivery by 1998 will be powered by alternative fuels, mostly by natural gas. There are over 2,200 natural gas buses in operation or on order, plus about 600 additional buses powered by other alternative fuels. When these orders are completed, alternative fuel buses will constitute over 4.4% of the urban bus fleet in the USA. The widespread use of natural gas buses in the USA provides an important transition pathway for hydrogen vehicles because of the similarities between distribution, refueling and onboard energy storage technologies for the two fuels. Projects demonstrating advanced hybrid-electric buses powered by natural gas or hydrogen and projects demonstrating hydrogen fuel cells in buses ...
Environmental targets and saving energy have become ones of the world main concerns over the last years and it will increase and become more important in a near future. The world population growth rate is the major factor contributing for the increase in global pollution and energy and water consumption. In 2005, the world population was approximately 6.5 billion and this number is expected to reach 9 billion by 2050 [United Nations, 2008. (www.un.org), accessed on July]. Water supply systems use energy for pumping water, so new strategies must be developed and implemented in order to reduce this consumption. In addition, if there is excess of hydraulic energy in a water system, some type of water power generation can be implemented. This paper presents an optimization model that determines the best hourly operation for 1 day, according to the electricity tariff, for a pumped storage system with water consumption and inlet discharge. Wind turbines are introduced in the system. The ...
Genetic mapping is approached using the techniques of high resolution fluorescence in situ hybridization (FISH). This technology and the results of its application are designed to rapidly generate whole genome as tool box of expressed sequence to speed the identification of human disease genes. The results of this study are intended to dovetail with and to link the results of existing technologies for creating backbone YAC and genetic maps. In the first eight months, this approach generated 60--80% of the expressed sequence map, the remainder expected to be derived through more long-term, labor-intensive, regional chromosomal gene searches or sequencing. The laboratory has made significant progress in the set-up phase, in mapping fetal and adult brain and other cDNAs, in testing a model system for directly linking genetic and physical maps using FISH with small fragments, in setting up a database, and in establishing the validity and throughput of the system.
Patients with acquired immunodeficiency syndrome (AIDS) are subject to a spectrum of central nervous system (CNS) disorders. Recent evidence implicates the human T-cell lymphotropic virus type III (HTLV-III) in the pathogenesis of some of these illnesses, although the cells infected by the virus have yet to be identified. Using in situ hybridization, the authors examined brain tissue from two patients with AIDS encephalopathy for the presence of HTLV-III RNA. In both cases, viral RNA was detected and concentrated in, though not limited to, the white matter. The CNS cells most frequently infected included macrophages, pleomorphic microglia, and multinucleated giant cells. Less frequently, cells morphologically consistent with astrocytes, oligodendroglia, and rarely neurons were also infected. The findings strengthen the association of HTLV-III with the pathogenesis of AIDS encephalopathy. In situ hybridization can be applied to routinely ...
In this study, the excitation functions for the reactions "2"0"3Tl(p, n)"2"0"3Pb, "2"0"5Tl(p, 3n)"2"0"3Pb, "2"0"3Tl(p, 2n)"2"0"2Pb, "2"0"5Tl(p, 4n)"2"0"2Pb, "2"0"3Tl(p, 3n)"2"0"1Pb, "2"0"5Tl(p, 5n)"2"0"1Pb, "2"0"3Tl(p, 4n)"2"0"0Pb and "2"0"5Tl(p, 6n)"2"0"0Pb have been calculated using pre-equilibrium and equilibrium reactions mechanisms. Calculated results based on hybrid model, geometry-dependent hybrid model and cascade-exciton model have been compared with the experimental data. (author)
The human CDC25 tyrosine phosphatases trigger activation of CDC2 by removing inhibitory phosphates; thus the genes encoding these phosphatases may be suspected as potential oncogenes due to their role in promoting cell division. To date, three human CDC25 genes have been identified: CDC25A, B, and C. This communication describes the mapping of CDC25A to chromosome 3p21 and CDC25B to chromosome 20p13 by fluorescence in situ hybridization with confirmation by the polymerase chain reaction of hamster-human somatic cell hybrid DNA. 3p21 is near an area frequently involved in karyotypic abnormalities in renal carcinomas, small cell carcinomas of the lung, and benign tumors of the salivary gland. 20p13 does not seem to be a common area for karyotypic alteration in tumors. Mapping of these genes to their chromosomal loci may help identify tumors with abnormal regulation of CDC25 genes due to genomic alterations. 15 refs., 3 figs.
The recently described retinoid X receptors (RXRs) respond to the novel retinoid 9-cis-retinoic acid and also serve as heterodimeric partners for the vitamin D, thyroid hormone, and retinoic acid receptors (VDR, TR, and RAR, respectively). In this work, the authors report high-resolution localization of the human RXR genes within cytogenetic bands and also within a standard reference map of cosmid DNA markers on human chromosomes. They have determined the location of the human RXR genes by pairwise hybridization of the RXR cosmids and reference markers, using fluorescence in situ hybridization. They localized (i) RXR[alpha] (RXRA) to chromosome 9 band q34.3; (ii) RXR[beta] (RXRB) to chromosome 6 band 21.3; and (iii) RXR[gamma] (RXRG) to chromosome 1 band q22-q23. Six retinoid-responsive transcription factors have been identified so far, including three retinoic acid receptors in addition to the three RXRs. Interestingly, each of these receptors ...
Novel hybrid organic/inorganic nanocomposites made of metal oxide and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells were studied. The composite was composed of different concentrations of strontium titanate (SrTiO_3) and polyaniline doped phosphoric acid. The optimum concentration of strontium titanate was found to be 0.2 v/v. An inorganic-organic photovoltaic device with a structure of Ag/Pani-H_3PO_4-SrTiO_3/Al has been fabricated. The ideality factor value of the diode was found to be 1.8. This n value of the diode implies a deviation from ideal junction behaviour. The barrier height #phi#_b value for the diode was found to be 0.56 eV. The Ag/Pani-H_3PO_4-SrTiO_3/Al diode shows a photovoltaic behaviour with a maximum open-circuit voltage V_o_c of 2.49 V, and short-circuit current I_s_c of 5.6 mA under light illumination #lambda# = 460 nm. The conversion efficiency was found to be 5.2%. It is evaluated that the ...