92,155 research outputs found
Vertical field-effect transistors in III-V semiconductors
Vertical metal-semiconductor field-effect transistors in GaAs/GaAlAs and vertical metal-oxide-semiconductor field-effect transistors (MOSFET's) in InP/GaInPAs materials have been fabricated. These structures make possible short channel devices with gate lengths defined by epitaxy rather than by submicron photolithography processes. Devices with transconductances as high as 280 mS/mm in GaAs and 60 mS/mm (with 100-nm gate oxide) for the InP/GaInPAs MOSFET's were observed
A Deep Relevance Matching Model for Ad-hoc Retrieval
In recent years, deep neural networks have led to exciting breakthroughs in
speech recognition, computer vision, and natural language processing (NLP)
tasks. However, there have been few positive results of deep models on ad-hoc
retrieval tasks. This is partially due to the fact that many important
characteristics of the ad-hoc retrieval task have not been well addressed in
deep models yet. Typically, the ad-hoc retrieval task is formalized as a
matching problem between two pieces of text in existing work using deep models,
and treated equivalent to many NLP tasks such as paraphrase identification,
question answering and automatic conversation. However, we argue that the
ad-hoc retrieval task is mainly about relevance matching while most NLP
matching tasks concern semantic matching, and there are some fundamental
differences between these two matching tasks. Successful relevance matching
requires proper handling of the exact matching signals, query term importance,
and diverse matching requirements. In this paper, we propose a novel deep
relevance matching model (DRMM) for ad-hoc retrieval. Specifically, our model
employs a joint deep architecture at the query term level for relevance
matching. By using matching histogram mapping, a feed forward matching network,
and a term gating network, we can effectively deal with the three relevance
matching factors mentioned above. Experimental results on two representative
benchmark collections show that our model can significantly outperform some
well-known retrieval models as well as state-of-the-art deep matching models.Comment: CIKM 2016, long pape
The Generalized Crewther Relation in QCD and its Experimental Consequences
We use the BLM scale-fixing prescription to derive a renormalization-scheme
invariant relation between the coefficient function for the Bjorken sum rule
for polarized deep inelastic scattering and the -ratio for the
annihilation cross section. This relation provides a generalization of the
Crewther relation to non-conformally invariant gauge theories. The derived
relations allow one to calculate unambiguously without renormalization scale or
scheme ambiguity the effective charges of the polarized Bjorken and the
Gross-Llewellen Smith sum rules from the experimental value for the effective
charge associated with -ratio. Present data are consistent with the
generalized Crewther relations, but measurements at higher precision and
energies will be needed to decisively test these fundamental relations in QCD.Comment: 16 pages, LATEX fil
R-Parity Conservation from a Top Down Perspective
Motivated by results from the LHC and dark matter searches, we study the
possibility of phenomenologically viable R-parity violation in GUT
models from a top-down point of view. We show that in contrast to the more
model dependent bounds on the proton lifetime, the limits on neutrino masses
provide a robust, stringent and complementary constraint on all
GUT-based R-parity violating models. Focusing on well-motivated string/
theory GUT frameworks with mechanisms for doublet-triplet splitting and a
solution to the problems, we show that imposing the neutrino mass
bounds implies that R-parity violation is disfavored. The arguments can also be
generalized to minimal GUTs. An experimental observation of R-parity
violation would, therefore, disfavor such classes of top-down GUT models.Comment: Citations added, accepted to JHEP with minor revision
- …