737 research outputs found
Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station
HERD is the High Energy cosmic-Radiation Detection instrument proposed to
operate onboard China's space station in the 2020s. It is designed to detect
energetic cosmic ray nuclei, leptons and photons with a high energy resolution
( for electrons and photons and for nuclei) and a large
geometry factor ( for electrons and diffuse photons and for nuclei). In this work we discuss the capability of HERD to detect
monochromatic -ray lines, based on simulations of the detector
performance. It is shown that HERD will be one of the most sensitive
instruments for monochromatic -ray searches at energies between
to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will
be more sensitive due to their large effective area. As a specific example, we
show that a good portion of the parameter space of a supersymmetric dark matter
model can be probed with HERD.Comment: 9 pages, 7 figures, matches version published in Astropart.Phy
General framework of quantum complementarity from a measurement-based perspective
One of the most remarkable features of quantum physics is that attributes of
quantum objects, such as the wave-like and particle-like behaviors of single
photons, can be complementary in the sense that they are equally real but
cannot be observed simultaneously. Quantum measurements, serving as windows
providing views into the abstract edifice of quantum theory, are basic tools
for manifesting the intrinsic behaviors of quantum objects. However,
quantitative formulation of complementarity that highlights its manifestations
in sophisticated measurements remains elusive. Here we develop a general
framework for demonstrating quantum complementarity in the form of information
exclusion relations (IERs), which incorporates the wave-particle duality
relations as particular examples. Moreover, we explore the applications of our
theory in entanglement witnessing and elucidate that our IERs lead to an
extended form of entropic uncertainty relations, providing intriguing insights
into the connection between quantum complementarity and the preparation
uncertainty.Comment: 13 pages (including 7 pages in the main text), 6 figure
ATCSpeech: a multilingual pilot-controller speech corpus from real Air Traffic Control environment
Automatic Speech Recognition (ASR) is greatly developed in recent years,
which expedites many applications on other fields. For the ASR research, speech
corpus is always an essential foundation, especially for the vertical industry,
such as Air Traffic Control (ATC). There are some speech corpora for common
applications, public or paid. However, for the ATC, it is difficult to collect
raw speeches from real systems due to safety issues. More importantly, for a
supervised learning task like ASR, annotating the transcription is a more
laborious work, which hugely restricts the prospect of ASR application. In this
paper, a multilingual speech corpus (ATCSpeech) from real ATC systems,
including accented Mandarin Chinese and English, is built and released to
encourage the non-commercial ASR research in ATC domain. The corpus is detailly
introduced from the perspective of data amount, speaker gender and role, speech
quality and other attributions. In addition, the performance of our baseline
ASR models is also reported. A community edition for our speech database can be
applied and used under a special contrast. To our best knowledge, this is the
first work that aims at building a real and multilingual ASR corpus for the air
traffic related research
Quantum theory of electronic double-slit diffraction
The phenomena of electron, neutron, atomic and molecular diffraction have
been studied by many experiments, and these experiments are explained by some
theoretical works. In this paper, we study electronic double-slit diffraction
with quantum mechanical approach. We can obtain the results: (1) When the slit
width is in the range of we can obtain the obvious
diffraction patterns. (2) when the ratio of , order are missing in
diffraction pattern. (3)When the ratio of , there isn't missing order in diffraction pattern. (4) We
also find a new quantum mechanics effect that the slit thickness has a
large affect to the electronic diffraction patterns. We think all the
predictions in our work can be tested by the electronic double-slit diffraction
experiment.Comment: 9pages, 14figure
Acetonitriletriaqua[3-ethoxy-1,8-(3,6,9-trioxaundecane-1,11-diyldioxy)-9H-xanthen-9-one]terbium(III) tris(perchlorate)
In the title compound, [Tb(CH3CN)(C23H26O8)(H2O)3](ClO4)3, the Tb3+ atom is eight-coordinated by one N atom of an acetonitrile molecule, three water O atoms and four ligand O atoms. The Tb3+ atom is located on one side of the macrocycle and the carbonyl oxygen coordinated to the terbium [Tb1—O1= 2.210 (3) Å] is bent out of the xanthone plane by 0.514 (3) Å. The geometry around terbium is a distorted two-capped trigonal prism
Molecular Characterization and Directed Evolution of a Metagenome-Derived l-Cysteine Sulfinate Decarboxylase
L-cistein sulfinat dekarboksilaza (EC 4.1.1.29) je enzim koji određuje brzinu biosinteze taurina, te katalizira dekarboksilaciju L-cistein sulfinskekiseline u hipotaurin. Identifikacija nove L-cistein sulfinat dekarboksilaze koja bi mogla poboljšati biosintetičku učinkovitost taurina vrlo je bitna. Još neistraženi gen za dekarboksilazu, undec1A, identificiran je u prethodnom radu probirom sekvencija DNA iz neuzgojenih mikroorganizama iz tla. Uproteinu Undec1A primjenjena je nasumična mutageneza pomoću sekvencijalne lančane reakcije polimeraze s pogreškama. Mutirani protein Undec1A-1180, izdvojen iz zbirke tako dobivenih različitih mutiranih proteina, imao je 5,62 puta veću specifičnu aktivnost od ishodnogproteina Undec1A pri temperaturi od 35 °C i pH=7,0. Rezultati molekulskog uklapanja potvrđuju da aminokiselinski ostaci Ala235, Val237, Asp239, Ile267, Ala268 i Lys298 u proteinu Undec1A-1180 pomažu pri prepoznavanju i katalizi molekula L-cistein sulfinske kiseline. Ovi bi rezultati mogli poslužiti kao osnova za definiranje svojstava proteina Undec1A-1180.Tehnologija usmjerene evolucije prikladna je za unapređenje biotehnološke primjene gena dobivenih iz metagenoma.L-Cysteine sulfinate decarboxylase (CSD, EC 4.1.1.29), the rate-limiting enzyme in taurine synthesis pathway, catalyzes L-cysteine sulfinic acid to form hypotaurine. Identification of the novel CSD that could improve the biosynthetic efficiency of taurine is important. An unexplored decarboxylase gene named undec1A was identified in a previous work through sequence-based screening of uncultured soil microorganisms. Random mutagenesis through sequential error-prone polymerase chain reaction was used in Undec1A. A mutant Undec1A-1180, which was obtained from mutagenesis library, had 5.62-fold higher specific activity than Undec1A at 35 °C and pH=7.0. Molecular docking results indicated that amino acid residues Ala235, Val237, Asp239, Ile267, Ala268, and Lys298 in the Undec1A-1180 protein helped recognize and catalyze the substrate molecules of L-cysteine sulfinic acid. These results could serve as a basis for elucidating the characteristics of the Undec1A-1180. Directed evolution technology is a convenient way to improve the biotechnological applications of metagenome-derived genes
- …