Recombination luminescence in N-type Czochralski silicon

Recombination luminescence in Czochralski silico

Radiation effects on lasers Technical report, Jul. 1, 1965 - May 31, 1966

Effects of space radiation on laser

Radiation effects on silicon solar cells Third monthly progress report, Mar. 1-31, 1962

Radiation effects on silicon solar cell

Independent Orbiter Assessment (IOA): Analysis of the landing/deceleration subsystem

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Landing/Deceleration Subsystem hardware. The Landing/Deceleration Subsystem is utilized to allow the Orbiter to perform a safe landing, allowing for landing-gear deploy activities, steering and braking control throughout the landing rollout to wheel-stop, and to allow for ground-handling capability during the ground-processing phase of the flight cycle. Specifically, the Landing/Deceleration hardware consists of the following components: Nose Landing Gear (NLG); Main Landing Gear (MLG); Brake and Antiskid (B and AS) Electrical Power Distribution and Controls (EPD and C); Nose Wheel Steering (NWS); and Hydraulics Actuators. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode. Due to the lack of redundancy in the Landing/Deceleration Subsystems there is a high number of critical items

FREE-FLIGHT MEASUREMENTS OF STATIC AND DYNAMIC STABILITY OF MODELS OF THE PROJECT MERCURY RE-ENTRY CAPSULE AT MACH NUMBERS 3 AND 9.5

Static & dynamic stability of mercury reentry capsule scale models at mach 3 & 9.

Radiation effects on lasers Final report, 1 Jul. 1965 - Oct. 1967

Space radiation effects on gallium arsenide laser diodes and optically pumped laser

Effects of sucrose and methylglyoxal bis-(guanylhydrazone) on controlling grape somatic embryogenesis

The effects of sucrose and methylglyoxal bis-(guanylhydrazone) (MGBG) on grape (Vitis vinifera L. cv. Thompson Seedless) somatic embryogenesis was examined by subculturing somatic embryos and embryogenic cells monthly to embryo maintenance medium (MMS) containing 60, 90, 120, 150, or 180 g/l sucrose; or 0, 0.1, 1, or 10 mM MGBG for three months. The growth and development of grape embryogenic cultures was inhibited by incubating them on MMS with 150 or 180 g/l sucrose compared to 60, 90, or 120 g/l. Culture dry weight was significantly greater for embryogenic cells grown on MMS with 90 or 120 g/l sucrose compared with those reared on standard MMS (60 g/l sucrose), indicating that embryogenic cells grew better on MMS with 90 or 120 g/l sucrose and were less hydrated. The number of cotyledonary-stage somatic embryos that resembled zygotic embryos was improved 10.8- to 21.3-fold by incubating grape embryogenic cells on MMS with 90 or 120 g/l sucrose, respectively. Germination-and plant development of grape somatic embryos was improved following incubation on MMS with 150 g/l sucrose before transfer to germination medium with benzyladenine. However, fewer embryos were produced on this medium compared to all other sucrose levels, suggesting that maintaining embryogenic cultures on MMS with 120 g/l sucrose followed by one transfer onto MMS with 150 g/l sucrose may improve embryo development and plant regeneration. MGBG at 1 to 10 mh I inhibited the growth and development of grape embryogenic cultures. Exposure of embryogenic cells to 10 mM MGBG inhibited their growth and development through the course of the experiment and caused their death by the third month of culture. In contrast, a 3-month exposure was required to inhibit embryo growth in the presence of 1 mM MGBG. Addition of MGBG to MMS did not improve embryo quality or plant development

A Bose-Einstein Condensate in a Uniform Light-induced Vector Potential

We use a two-photon dressing field to create an effective vector gauge potential for Bose-condensed Rb atoms in the F=1 hyperfine ground state. The dressed states in this Raman field are spin and momentum superpositions, and we adiabatically load the atoms into the lowest energy dressed state. The effective Hamiltonian of these neutral atoms is like that of charged particles in a uniform magnetic vector potential, whose magnitude is set by the strength and detuning of Raman coupling. The spin and momentum decomposition of the dressed states reveals the strength of the effective vector potential, and our measurements agree quantitatively with a simple single-particle model. While the uniform effective vector potential described here corresponds to zero magnetic field, our technique can be extended to non-uniform vector potentials, giving non-zero effective magnetic fields.Comment: 5 pages, submitted to Physical Review Letter

Quantitative localized proton-promoted dissolution kinetics of calcite using scanning electrochemical microscopy (SECM)

Scanning electrochemical microscopy (SECM) has been used to determine quantitatively the kinetics of proton-promoted dissolution of the calcite (101̅4) cleavage surface (from natural “Iceland Spar”) at the microscopic scale. By working under conditions where the probe size is much less than the characteristic dislocation spacing (as revealed from etching), it has been possible to measure kinetics mainly in regions of the surface which are free from dislocations, for the first time. To clearly reveal the locations of measurements, studies focused on cleaved “mirror” surfaces, where one of the two faces produced by cleavage was etched freely to reveal defects intersecting the surface, while the other (mirror) face was etched locally (and quantitatively) using SECM to generate high proton fluxes with a 25 μm diameter Pt disk ultramicroelectrode (UME) positioned at a defined (known) distance from a crystal surface. The etch pits formed at various etch times were measured using white light interferometry to ascertain pit dimensions. To determine quantitative dissolution kinetics, a moving boundary finite element model was formulated in which experimental time-dependent pit expansion data formed the input for simulations, from which solution and interfacial concentrations of key chemical species, and interfacial fluxes, could then be determined and visualized. This novel analysis allowed the rate constant for proton attack on calcite, and the order of the reaction with respect to the interfacial proton concentration, to be determined unambiguously. The process was found to be first order in terms of interfacial proton concentration with a rate constant k = 6.3 (± 1.3) × 10–4 m s–1. Significantly, this value is similar to previous macroscopic rate measurements of calcite dissolution which averaged over large areas and many dislocation sites, and where such sites provided a continuous source of steps for dissolution. Since the local measurements reported herein are mainly made in regions without dislocations, this study demonstrates that dislocations and steps that arise from such sites are not needed for fast proton-promoted calcite dissolution. Other sites, such as point defects, which are naturally abundant in calcite, are likely to be key reaction sites