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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Theoretical perspective on phase stability and polarization switching in ferroelectric hafnia

Fluorite-based ferroelectric materials are revolutionizing the application space of polar semiconductors. These materials leverage robust polarization of extremely thin films, compatibility with the silicon chip processing, and decades of manufacturing experience to enable a new generation of ferroelectric memory devices. As a new paradigm for ferroelectrics, understanding of phase transitions and the switching mechanism in fluorites is essential both for advancing applications and for fundamental science. In this article, we outline the recent progress that has been made to understand the relative phase stability, phase transition and order parameter coupling, ferroelectric switching through unique nucleation and growth processes, and how defects affect these phases and processes. The main challenges, opportunities, and next steps for leveraging these materials for next-generation devices are reviewed.

Condensed Matter Physics↗
DOE OSTI2024

Entropy Analysis of FPGA Interconnect and Switch Matrices for Physical Unclonable Functions

Random variations in microelectronic circuit structures represent the source of entropy for physical unclonable functions (PUFs). In this paper, we investigate delay variations that occur through the routing network and switch matrices of a field-programmable gate array (FPGA). The delay variations are isolated from other components of the programmable logic, e.g., look-up tables (LUTs), flip-flops (FFs), etc., using a feature of Xilinx FPGAs called dynamic partial reconfiguration (DPR). A set of partial designs is created to fix the placement of a time-to-digital converter (TDC) and supporting infrastructure to enable the path delays through the target interconnect and switch matrices to be extracted by subtracting out common-mode delay components. Delay variations are analyzed in the different levels of routing resources available within FPGAs, i.e., local routing and across-chip routing. Data are collected from a set of Xilinx Zynq 7010 devices, and a statistical analysis of within-die variations in delay through a set of the randomly-generated and hand-crafted interconnects is presented.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Sub-Nanosecond, Room-Temperature, Mid-IR Fe:ZnSe Gain-Switched Laser: Experimental Characterization and Modeling

We present the modeling and experimental characterization of a room-temperature, sub-nanosecond, gain-switched (GS) Fe:ZnSe laser operating at 4.4–4.8 μm. As pump sources, we used a 2.79 µm Q-switched Cr:Er:YSGG laser with a pulse duration of 52 ns and the 2.98 μm idler of a Nd:YAG pumped KTA-OPO system with a pulse duration of 9 ns. The shortest pulse durations were measured to be 1.4 ns and 0.7 ns under excitation by the Cr:Er:YSGG laser and KTA-OPO system, respectively. The developed Fe:ZnSe laser model showed good agreement with the experimental results. Optimization of the laser parameters based on model simulations suggests that an Fe:ZnSe microchip laser configuration could be achieved with a pulse duration of ~250 ps and an efficiency of ~20%.

Ghimire, Saugat↗
NASA NTRS1964

Double-throw microwave device switches two lines quickly

By combining a single-throw microwave switch with a microwave circulator in a circuit, two input lines can be switched quickly. There is only a brief transition time when both /or neither/ of the two lines are connected to an output line.

Clauss, R.↗
NASA NTRS1965

Cam-operated limit switch features safe fuse replacement

Two hermetically sealed, short travel, limit switches permit fuse replacement without danger of a spark or arcing. The switches are wired in parallel circuits and actuated by manually operated cams containing the circuit fuses.

Weber, G. J.↗
NASA NTRS1966

Flexible arms provide constant force for pressure switch calibration

In-place calibration of a pressure switch is provided by a system of radially oriented flexing arms which, when rotated at a known velocity, convert the centrifugal force of the arms to a linear force along the shaft. The linear force, when applied to a pressure switch diaphragm, can then be calculated.

Cain, D. E.↗
NASA NTRS1966

Solid state circuit switches ac load

Differential amplifier circuit switches ac signals with peak amplitudes greater than 5 volts. This solid state circuit biases a switching transistor on and off by a 0.1 to 5.0 dc control voltage.

Chapman, C. P.↗
NASA NTRS1966

Design concept for pressure switch calibrator

Calibrator and switch design enables pressure switches to operate under 150 g shock loads. The design employs a saturated liquid-to-vapor phase transition at constant pressure to produce a known force independent of displacement over a usable range.

Slingerland, M. G.↗
NASA NTRS1967

Automatic channel switching device

Automatic channel switching device operates with all three triple modular redundant channels when there are no errors. When a failure occurs, channel and module switching isolate the failure to a specific channel. Since only one must operate correctly, reliability is increased.

Ball, M.↗
NASA NTRS1967

Rugged switch responds to minute pressure differentials

Pressure responsive switching device exhibits high sensitivity but is extremely rugged and resistant to large amplitude shock and velocity loading. This snap-action, single pole-double throw switch operates over a wide temperature range.

Friend, L. C.↗
NASA NTRS1968

Bilateral, Zero-Impedance Static Semiconductor Switch

Static semiconductor switching circuit eliminates the undesirable features of electromechanical relays and conventional semiconductor switching circuits. There is a net zero voltage drop at the terminals and thus a zero impedance for bilateral currents there.

Doughman, C. L.↗
NASA NTRS1968

High conductance vapor thermal switch

High conductance vapor thermal switch was produced to maintain heat dissipating component temperatures within acceptable limits. The switch is a self-actuating, automatic device that regulates the rate of heat flow to control.

Hyman, N. L.↗
NASA NTRS1969

Simple switch actuated by force applied over wide solid angle

Electric switch can be actuated /closed/ by a force applied from any direction within a hemispheric envelope. The switch is comprised of a flexible, electrically conductive reed holding a conductive contact disc, mounted concentrically within a conductive tube.

Nelson, B.↗
NASA NTRS1969

Calibratable solid-state pressure switch

Pressure switch, incorporating a semiconductor light-detector coupled to an electrically controlled actuating unit, provides accurate and reliable switching over a broad range of pressures and environments.

Source record↗