1,890 research outputs found
Behavior of the lean methane-air flame at zero-gravity
A special rig was designed and constructed to be compatible with the NASA Lewis Research Center Airborne Research Laboratory to allow the study of the effect of gravity on the behavior of lean limit in a standard 50.4 mm (2 in.) internal diameter tube when the mixtures are ignited at the open end and propagate towards the closed end of the tube. The lean limit at zero gravity was found to be 5.10% methane and the flame was found to extenguish in a manner previously observed for downward propagating flames at one g. It was observed that g-jitter could be maintained at less than + or 0.04 g on most zero g trajectories. All of propagating lean limit flames were found to be sporadically cellularly unstable at zero g. There was no observable correlation between the occurrence of g-jitter and the lean limit, average propagation speed of the flame through the tube or the occurrence of cellular instability
High-temperature superconducting fault current microlimiters
High-temperature superconducting microbridges implemented with
YBa(2)Cu(3)O(7-delta) thin-films are shown to be possible fault current
limiters for microelectronic devices with some elements working at temperatures
below the superconducting critical temperature and, simultaneously, under very
low power conditions (below 1W). This is the case in the important applications
of superconductors as SQUID based electronics, and technologies for
communication or infrared detectors. In this paper it is shown that the good
thermal behavior of these microlimiters allows working in a regime where even
relatively small faults induce their transition to highly dissipative states,
dramatically increasing their limitation efficiency. The conditions for optimal
refrigeration and operation of these microlimiters are also proposed.Comment: 10 pages, 3 figures. LaTeX and EPS file
Semicontinuous Bioreactor Production of Recombinant Butyrylcholinesterase in Transgenic Rice Cell Suspension Cultures.
An active and tetrameric form of recombinant butyrylcholinesterase (BChE), a large and complex human enzyme, was produced via semicontinuous operation in a transgenic rice cell suspension culture. After transformation of rice callus and screening of transformants, the cultures were scaled up from culture flask to a lab scale bioreactor. The bioreactor was operated through two phases each of growth and expression. The cells were able to produce BChE during both expression phases, with a maximum yield of 1.6 mg BChE/L of culture during the second expression phase. Cells successfully regrew during a 5-day growth phase. A combination of activity assays and Western blot analysis indicated production of an active and fully assembled tetramer of BChE
Ein einfaches Verfahren zur Herstellung anellierter Thiophene
A simple method for the synthesis of fused thiophenes by reaction of agr-carboxymethyl substituted cyclic ketones withLawesson-reagent is described. Considerations concerning the reaction mechanism are given
Crater Morphology in the Phoenix Landing Ellipse: Insights Into Net Erosion and Ice Table Depth
Icebreaker [1] is a Discovery class mission being developed for future flight opportunities. Under this mission concept, the Icebreaker payload is carried on a stationary lander, and lands in the same landing ellipse as Phoenix. Samples are acquired from the subsurface using a drilling system that penetrates into materials which may include loose or cemented soil, icy soil, pure ice, rocks, or mixtures of these. To avoid the complexity of mating additional strings, the drill is single-string, limiting it to a total length of 1 m
Syntax-driven Iterative Expansion Language Models for Controllable Text Generation
The dominant language modeling paradigm handles text as a sequence of
discrete tokens. While that approach can capture the latent structure of the
text, it is inherently constrained to sequential dynamics for text generation.
We propose a new paradigm for introducing a syntactic inductive bias into
neural text generation, where the dependency parse tree is used to drive the
Transformer model to generate sentences iteratively.
Our experiments show that this paradigm is effective at text generation, with
quality between LSTMs and Transformers, and comparable diversity, requiring
less than half their decoding steps, and its generation process allows direct
control over the syntactic constructions of the generated text, enabling the
induction of stylistic variations.Comment: Accepted at the EMNLP 2020 Workshop on Structured Prediction for NL
Low cost multi-channel GPS receiver
©1988 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.An investigation was conducted on compact, multichannel GPS (global positioning system) receivers. The code generator and correlation equipment were simplified, attempting to avoid downgrading the properties possessed by multichannel receivers as much as possible, and the error-increasing factors caused by such modification were examined. As a means of simplifying the receiver hardware, phases with a unit of 1/8 chip were established in the code generator. Each channel was provided with a circuit for determining correlation, and the phase differences of the carrier and the code were measured by time division. It was confirmed that sufficient accuracy of measurement can be obtained even if such simplification is carried out
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