7,172 research outputs found
Modelling shoreline movement using two extreme beachface slopes
A new algorithm to simulate shoreline movement at general planar coastal morphology is proposed here. Two limiting slopes and a reference level are involved in this algorithm. If beach slope exceeds a certain value during numerical morphological modelling, the beach profile undergoes correction by moving some sediment volume to underwater zone. If beach slope becomes smaller than the other slope, the beach profile is corrected by moving some sediment volume to onshore zone. Final adjustment is carried out to sort out three-dimensionality. The algorithm is applied to a laboratory experiment showing tombolo generation behind a detached breakwater, and demonstrates its usefulness with reasonable accuracy
Design and construction of a remote monitoring and control system for a dehumidifier combined with a heating module
Background: Protected cultivation (e.g., greenhouse) is spreading mainly for high-income crops such as paprika, strawberry, and tomato. The temperature and the humidity are especially important during cultivation. A dehumidifier combined with a heating module is under development. In the study, a remote monitoring and control system for the prototype was designed and constructed.
Methods: The dehumidifier prototype was composed of a dehumidifier, a fan blower, and heating modules. The remote monitoring and control system was composed of temperature-humidity measuring sensor network, a central processing module, a dehumidifier network, and smartphone application. First, the sensing network was tested for different communication distances and number of data variables. Second, remote monitoring and control performance was tested using the smartphone application by signal intensity and time of the day.
Results and discussion: Monitoring performance was favourable within 15 m distance with the tested ZigBee module, and a wireless communication network was established considering the communication distance and greenhouse length (i.e., 100 m). Remote monitoring and control was successful for all of the tested signal intensity and time of the day, although the data transmission speed was affected significantly. Components of the dehumidifier were successfully controlled within 30 s.
Conclusion: The remote monitoring and control system was tested only under experimental conditions. For improved performance and practical application, the prototype needs to be further tested under crop growing conditions, and the control algorithm needs to be also improved
Reduced dopant-induced scattering in remote charge-transfer-doped MoS<sub>2</sub> field-effect transistors
Efficient doping for modulating electrical properties of two-dimensional (2D) transition metal dichalcogenide (TMDC) semiconductors is essential for meeting the versatile requirements for future electronic and optoelectronic devices. Because doping of semiconductors, including TMDCs, typically involves generation of charged dopants that hinder charge transport, tackling Coulomb scattering induced by the externally introduced dopants remains a key challenge in achieving ultrahigh mobility 2D semiconductor systems. In this study, we demonstrated remote charge transfer doping by simply inserting a hexagonal boron nitride layer between MoS2 and solution-deposited n-type dopants, benzyl viologen. A quantitative analysis of temperature-dependent charge transport in remotely doped devices supports an effective suppression of the dopant-induced scattering relative to the conventional direct doping method. Our mechanistic investigation of the remote doping method promotes the charge transfer strategy as a promising method for material-level tailoring of electrical and optoelectronic devices based on TMDCs
Double polarization hysteresis loop induced by the domain pinning by defect dipoles in HoMnO3 epitaxial thin films
We report on antiferroelectriclike double polarization hysteresis loops in
multiferroic HoMnO3 thin films below the ferroelectric Curie temperature. This
intriguing phenomenon is attributed to the domain pinning by defect dipoles
which were introduced unintentionally during film growth process. Electron
paramagnetic resonance suggests the existence of Fe1+ defects in thin films and
first principles calculations reveal that the defect dipoles would be composed
of oxygen vacancy and Fe1+ defect. We discuss migration of charged point
defects during film growth process and formation of defect dipoles along
ferroelectric polarization direction, based on the site preference of point
defects. Due to a high-temperature low-symmetry structure of HoMnO3, aging is
not required to form the defect dipoles in contrast to other ferroelectrics
(e.g., BaTiO3).Comment: 4 figure
Construction of Yemilab
The Center for Underground Physics of the Institute for Basic Science (IBS)
in Korea has been planning the construction of a deep underground laboratory
since 2013 to search for extremely rare interactions such as dark matter and
neutrinos. In September 2022, a new underground laboratory, Yemilab, was
finally completed in Jeongseon, Gangwon Province, with a depth of 1,000 m and
an exclusive experimental area spanning 3,000 m. The tunnel is encased in
limestone and accommodates 17 independent experimental spaces. Over two years,
from 2023 to 2024, the Yangyang Underground Laboratory facilities will be
relocated to Yemilab. Preparations are underway for the AMoRE-II, a
neutrinoless double beta decay experiment, scheduled to begin in Q2 2024 at
Yemilab. Additionally, Yemilab includes a cylindrical pit with a volume of
approximately 6,300 m, designed as a multipurpose laboratory for
next-generation experiments involving neutrinos, dark matter, and related
research. This article provides a focused overview of the construction and
structure of Yemilab.Comment: 12 pages, 3 figures, 1 tabl
Calcium Silicate-Based Biocompatible Light-Curable Dental Material for Dental Pulpal Complex
Dental caries causes tooth defects and clinical treatment is essential. To prevent further damage and protect healthy teeth, appropriate dental material is a need. However, the biocompatibility of dental material is needed to secure the oral environment. For this purpose, biocompatible materials were investigated for incorporated with dental capping material. Among them, nanomaterials are applied to dental materials to enhance their chemical, mechanical, and biological properties. This research aimed to study the physicochemical and mechanical properties and biocompatibility of a recently introduced light-curable mineral trioxide aggregate (MTA)-like material without bisphenol A-glycidyl methacrylate (Bis-GMA). To overcome the compromised mechanical properties in the absence of Bis-GMA, silica nanoparticles were synthesized and blended with a dental polymer for the formation of a nano-network. This material was compared with a conventional light-curable MTA-like material that contains Bis-GMA. Investigation of the physiochemical properties followed ISO 4049. Hydroxyl and calcium ion release from the materials was measured over 21 days. The Vickers hardness test and three-point flexural strength test were used to assess the mechanical properties. Specimens were immersed in solutions that mimicked human body plasma for seven days, and surface characteristics were analyzed. Biological properties were assessed by cytotoxicity and biomineralization tests. There was no significant difference between the tested materials with respect to overall physicochemical properties and released calcium ions. The newly produced material released more calcium ions on the third day, but 14 days later, the other material containing Bis-GMA released higher levels of calcium ions. The microhardness was reduced in a low pH environment, and differences between the specimens were observed. The flexural strength of the newly developed material was significantly higher, and different surface morphologies were detected. The recently produced extract showed higher cell viability at an extract concentration of 100%, while mineralization was clear at the conventional concentration of 25%. No significant changes in the physical properties between Bis-GMA incorporate material and nanoparticle incorporate materials
Production and optical properties of liquid scintillator for the JSNS experiment
The JSNS (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron
Source) experiment will search for neutrino oscillations over a 24 m short
baseline at J-PARC. The JSNS inner detector will be filled with 17 tons
of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of
unloaded LS in the intermediate -catcher and outer veto volumes.
JSNS has chosen Linear Alkyl Benzene (LAB) as an organic solvent because
of its chemical properties. The unloaded LS was produced at a refurbished
facility, originally used for scintillator production by the RENO experiment.
JSNS plans to use ISO tanks for the storage and transportation of the LS.
In this paper, we describe the LS production, and present measurements of its
optical properties and long term stability. Our measurements show that storing
the LS in ISO tanks does not result in degradation of its optical properties.Comment: 7 pages, 4 figures
Progress on the Electromagnetic Calorimeter Trigger Simulation at the Belle II Experiment
The Belle II experiment at KEK in Japan has started real data taking from
April 2018 to probe a New Physics beyond the Standard Model by measuring CP
violation precisely and rare weak decays of heavy quark and lepton. The
experiment is performed at the high luminosity SuperKEKB e^+ e^- collider with
80 x 10^34 cm^-2 s^-1 as an ultimate instantaneous luminosity. In order to
develop and test an appropriate trigger algorithm under much higher luminosity
and beam background environment than previous KEKB collider, a detail
simulation study of the Belle II calorimeter trigger system is very crucial to
operate Belle II Trigger and DAQ system in stable. We report preliminary
results on various trigger logics and their efficiencies using physics and beam
background Monte Carlo events with a Belle II Geant4-based analysis framework
called Basf2
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