A5003077129- Physics of Superconductivity and Magnetism
- Spacecraft Design and Technology
- Space Satellite Systems and Control
- Rare-earth and actinide compounds
- Magnetic and transport properties of perovskites and related materials
- Spacecraft and Cryogenic Technologies
- Advanced Condensed Matter Physics
- Planetary Science and Exploration
- Iron-based superconductors research
- Magnetic properties of thin films
- Space exploration and regulation
- Electronic and Structural Properties of Oxides
- Space Exploration and Technology
- Technology Assessment and Management
- Distributed systems and fault tolerance
- Underwater Vehicles and Communication Systems
- Underwater Acoustics Research
- Astro and Planetary Science
- Advanced Manufacturing and Logistics Optimization
- Magnetic confinement fusion research
- Advanced Fluorescence Microscopy Techniques
- Surface and Thin Film Phenomena
- Magnetic Properties of Alloys
- Analytical Chemistry and Sensors
- Island Studies and Pacific Affairs
Hohai University
2017
Defense Advanced Research Projects Agency
2015-2016
UNSW Sydney
2013
University of Southern California
2011
Booz Allen Hamilton (United States)
2000
United States Naval Research Laboratory
1994
Massachusetts Institute of Technology
1990-1992
MIT Lincoln Laboratory
1989
United States Department of the Navy
1977
Draper Laboratory
1977
A primary goal of the Defense Advanced Research Projects Agency is to develop innovative, high-risk technologies with potential a revolutionary impact on missions Department Defense. DARPA developing space experiment prove feasibility autonomous on- orbit servicing spacecraft. The Orbital Express program will demonstrate on-orbit refueling, as well delivery small payload representing an avionics upgrade package. maneuverability provided spacecraft from ready refueling infrastructure enable...
Tunnel junctions were formed by depositing a thin layer of ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$(20 A\r{}) and Al counter electrodes onto sputtered annealed Bi-Sr-Ca-Cu-O films. Differential conductance spectra displayed low conductivity at bias, two pairs peaks, symmetric with respect to zero which correlate in energy relative magnitude the superconducting phases present film (110 85 K). The measured values peak positions reduced gap parameter are ${\ensuremath{\Delta}}_{1}$=18--21 meV(85-K...
Abstract The design of systems with complex interdependencies requires evaluation a vast number potential designs against performance and cost based metrics. For example, the Defense Advanced Research Projects Agency's (DARPA's) System F6 (Future Fast, Flexible, Fractionated, Free-Flying Spacecraft united by Information eXchange) program aims to demonstrate feasibility satellite fractionation. In major departure from traditional “monolithic” satellites, an system is cluster heterogeneous,...
Let's say you are the program manager of a very large, complex system. Perhaps it's an aircraft, or building, communications network. Your system is valued at over US $500 million. Could imagine being told that won't ever be able to maintain it? That, once operational, it will never inspected, repaired, upgraded with new hardware? . Welcome world satellite building. After launched, on one-way journey disrepair and obsolescence, there little anyone can do alter path. Faults (which called...
A variety of viewpoints can be heard concerning the utility on-orbit satellite servicing, maturity robotic systems being developed to address servicing opportunities, and viability business cases. This paper seeks quantify opportunities myths directly. Based on that analysis, we further refine models using a vehicle parameters identify promising configurations missions. We review past for geostationary Earth orbit (GEO) interventions both unexpected anomalies lifetime extension. These are...
Novel electronic properties are observed in metals contact with the ferromagnetic insulator europium monoxide (EuO). We have successfully prepared epitaxial bilayers and multilayers involving EuO V or Ag. With metal layers of 100 angstroms thickness less, these structures exhibit a slope discontinuity their resistance versus temperature at 90 K for V/EuO interfaces 50 Ag/EuO interfaces. For less than about 40 angstroms, feature is also apparent R(T) 70 K, Curie bulk EuO. The discontinuities...
the objective of this paper is to report latest developments in acoustic underwater navigation. The prime area concern will be accuracy: first, establishment a transponder navigation field and new techniques for survey that field; second, determination study multipath propagation limit range errors. Results in–situ tests determine characteristics both interrogation signals reply are presented.
Economic exploitation of lunar resources may be more efficient with a non-rocket approach to launch from the surface. The system cost will depend on its design, and number launches Earth deliver Moon. Both these launcher mass. Properties an electromagnetic resource are derived two mature terrestrial launchers. A mass model is used estimate costs for developmental vehicle. rough manufacturing suggested.
A planar tunnel diode with Ba/sub 1-x/K/sub x/BiO/sub 3/ (BKBO) and Ag electrodes were fabricated. The dynamic conductance of the junction was similar to that found conventional BCS superconductors. Using weak coupling theory, undepaired transition temperature, spin-orbit scattering rate, diffusion constant BKBO determined. Pauli-limited critical field calculated compared measured resistive transitions film in magnetic fields. is observed occur generally at where normal-state resistance...
Electricity production from ocean waves has the theoretical advantages of higher capacity factor, lower short-term variability, and longer forecasting horizons, when compared to wind photovoltaic sources. Potential applications wave-generated energy, in light these advantages, include: energy services; regulating reserves; contingency reserves. To provide services reliably economically, time variability wave resource must be clearly understood. Also, are provided context real-time or...
Acoustic transponders are employed in underwater navigation situations which a high degree of accuracy is required. Typical applications include search, mapping, photography by submersible or towed vehicle and positioning work systems. The network transponders, there may be only two three, very extensive, implanted support ship submersible. can located geographically satellite equipment to an 0·25 nm. This (or even within ± 1 mile) sufficient locate the after period disuse. accomplished...
Epitaxial bilayers and multilayers were prepared using the ferromagnetic insulator EuO metals V Ag. For metal films of thickness 10 nm or less, there is a sharp change in slope resistivity versus temperature, which occurs at 86 K for EuO/V specimens 50 EuO/Ag specimens. Soft x-ray magnetic circular dichroism measurements showed clear Eu but none V. Therefore, dR/dT discontinuity attributed to spin-dependent surface scattering insulator/metal interface caused by magnetization layer Eu++ ions....
High-quality thin films of ${\mathrm{CeAl}}_{3}$ with preferentially oriented crystal structure have been prepared, allowing unambiguous measurement the orientation dependence magnetoresistance \ensuremath{\Delta}\ensuremath{\rho}; a very large anisotropy is observed. When magnetic field applied along c axis, positive transverse \ensuremath{\Delta}\ensuremath{\rho} exhibited over much larger region H and T than case bulk polycrystalline samples. Kondo scattering diminished in this when below...
Developing a robotic servicing vehicle (RSV) capable of providing high-value, reliable services to satellites in geosynchronous Earth orbit (GEO) require solving myriad technical challenges and answering numerous regulatory policy questions. One such challenge is space/ground communications. Space/ground communications present significant the RSV designer: establishing means by which would receive commands from send telemetry, including video, its ground controllers during critical...
Thin films of the high-T/sub c/ material Bi-Sr-Ca-Cu-O were prepared by RF-magnetron technique from a single reacted and sintered target in pure argon atmosphere on sapphire substrates. The samples annealed for three minutes oxygen at 810 degrees C. Their composition was studied Rutherford backscattering. superconducting transition very broad, with R=O 65 K best film. MgO substrates nonsintered targets also used. behavior resistance magnetic field (up to 20 T) studied.< <ETX...