9,408 research outputs found
EXPERIMENTAL STUDY ON THE MECHANICAL AND DEFORMATION PROPERTIES OF PIPE AND SOIL IN RECTANGULAR PIPE JACKING CONSTRUCTION WITH CONTROLLABLE CEMENT GROUTING TECHNOLOGY
Based on the utility tunnel project of Chengbei Road in Suzhou, the experimental study on the mechanical and deformation properties of pipe and soil in rectangular pipe jacking construction with controllable cement grouting drag reduction technology is carried out. Based on the monitoring and analysis of pipe and soil stress and deformation of pipe joints during pipe jacking, the relevant theoretical model is established and the finite element simulation is carried out to experimentally study and compare the stress and deformation of pipe and soil in rectangular pipe jacking construction with controllable cement grouting drag reduction technology. The results show that the controllable cement grouting drag reduction technology has a significant effect on the pipe and soil stress in rectangular pipe jacking, which reduces pipe-soil interaction forces effectively, and improves the overall safety of pipe jacking construction
A supramolecular radical cation: folding-enhanced electrostatic effect for promoting radical-mediated oxidation.
We report a supramolecular strategy to promote radical-mediated Fenton oxidation by the rational design of a folded host-guest complex based on cucurbit[8]uril (CB[8]). In the supramolecular complex between CB[8] and a derivative of 1,4-diketopyrrolo[3,4-c]pyrrole (DPP), the carbonyl groups of CB[8] and the DPP moiety are brought together through the formation of a folded conformation. In this way, the electrostatic effect of the carbonyl groups of CB[8] is fully applied to highly improve the reactivity of the DPP radical cation, which is the key intermediate of Fenton oxidation. As a result, the Fenton oxidation is extraordinarily accelerated by over 100 times. It is anticipated that this strategy could be applied to other radical reactions and enrich the field of supramolecular radical chemistry in radical polymerization, photocatalysis, and organic radical battery and holds potential in supramolecular catalysis and biocatalysis
Effects of Rashba spin-orbit coupling and a magnetic field on a polygonal quantum ring
Using standard quantum network method, we analytically investigate the effect
of Rashba spin-orbit coupling (RSOC) and a magnetic field on the spin transport
properties of a polygonal quantum ring. Using Landauer-Buttiker formula, we
have found that the polarization direction and phase of transmitted electrons
can be controlled by both the magnetic field and RSOC. A device to generate a
spin-polarized conductance in a polygon with an arbitrary number of sides is
discussed. This device would permit precise control of spin and selectively
provide spin filtering for either spin up or spin down simply by interchanging
the source and drain
Involvement of the JNK/FOXO3a/Bim Pathway in Neuronal Apoptosis after Hypoxic-Ischemic Brain Damage in Neonatal Rats.
c-Jun N-terminal kinase (JNK) plays a key role in the regulation of neuronal apoptosis. Previous studies have revealed that forkhead transcription factor (FOXO3a) is a critical effector of JNK-mediated tumor suppression. However, it is not clear whether the JNK/FOXO3a pathway is involved in neuronal apoptosis in the developing rat brain after hypoxia-ischemia (HI). In this study, we generated an HI model using postnatal day 7 rats. Fluorescence immunolabeling and Western blot assays were used to detect the distribution and expression of total and phosphorylated JNK and FOXO3a and the pro-apoptotic proteins Bim and CC3. We found that JNK phosphorylation was accompanied by FOXO3a dephosphorylation, which induced FOXO3a translocation into the nucleus, resulting in the upregulation of levels of Bim and CC3 proteins. Furthermore, we found that JNK inhibition by AS601245, a specific JNK inhibitor, significantly increased FOXO3a phosphorylation, which attenuated FOXO3a translocation into the nucleus after HI. Moreover, JNK inhibition downregulated levels of Bim and CC3 proteins, attenuated neuronal apoptosis and reduced brain infarct volume in the developing rat brain. Our findings suggest that the JNK/FOXO3a/Bim pathway is involved in neuronal apoptosis in the developing rat brain after HI. Agents targeting JNK may offer promise for rescuing neurons from HI-induced damage
Concurrence-Aware Long Short-Term Sub-Memories for Person-Person Action Recognition
Recently, Long Short-Term Memory (LSTM) has become a popular choice to model
individual dynamics for single-person action recognition due to its ability of
modeling the temporal information in various ranges of dynamic contexts.
However, existing RNN models only focus on capturing the temporal dynamics of
the person-person interactions by naively combining the activity dynamics of
individuals or modeling them as a whole. This neglects the inter-related
dynamics of how person-person interactions change over time. To this end, we
propose a novel Concurrence-Aware Long Short-Term Sub-Memories (Co-LSTSM) to
model the long-term inter-related dynamics between two interacting people on
the bounding boxes covering people. Specifically, for each frame, two
sub-memory units store individual motion information, while a concurrent LSTM
unit selectively integrates and stores inter-related motion information between
interacting people from these two sub-memory units via a new co-memory cell.
Experimental results on the BIT and UT datasets show the superiority of
Co-LSTSM compared with the state-of-the-art methods
Physical properties of CO-dark molecular gas traced by C
Neither HI nor CO emission can reveal a significant quantity of so-called
dark gas in the interstellar medium (ISM). It is considered that CO-dark
molecular gas (DMG), the molecular gas with no or weak CO emission, dominates
dark gas. We identified 36 DMG clouds with C emission (data from Galactic
Observations of Terahertz C+ (GOT C+) project) and HINSA features. Based on
uncertainty analysis, optical depth of HI of 1 is a reasonable
value for most clouds. With the assumption of , these clouds
were characterized by excitation temperatures in a range of 20 K to 92 K with a
median value of 55 K and volume densities in the range of
cm to cm with a median value of
cm. The fraction of DMG column density in the cloud ()
decreases with increasing excitation temperature following an empirical
relation +1.0. The relation
between and total hydrogen column density is given by
=. The values of in the
clouds of low extinction group ( mag) are consistent with the
results of the time-dependent, chemical evolutionary model at the age of ~ 10
Myr. Our empirical relation cannot be explained by the chemical evolutionary
model for clouds in the high extinction group ( mag). Compared to
clouds in the low extinction group ( mag), clouds in the high
extinction group ( mag) have comparable volume densities but
excitation temperatures that are 1.5 times lower. Moreover, CO abundances in
clouds of the high extinction group ( mag) are
times smaller than the canonical value in the Milky Way. #[Full version of
abstract is shown in the text.]#Comment: Accepted for publishing in Astronomy & Astrophysics. 13 pages, 8
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