bluuebunny/crossref_metadata_2025 huggingface dataset:
Python programming code for stellar photometry in astrophysics teaching on a cloud computing service
Authors: Krittinatham W , Kaewkhong K , Emarat N
Published: February 2023

Nowadays, there is various software used for both education and astronomy research. For photometry, licensed software and high-performance computer operating systems are required, which is a fund limitation for some schools in Thailand. Thus, in this article, we develop and present the Demonstration Photometry Scripts for Astrophysics Teaching (DPSAT version 1.0). The program is designed to work on cloud computing services via internet browsers to avoid hardware and operation requirement pain points. The DPSAT is programming on flexible, low-cost, on-trend language, Python, and Jupyter Notebook online editor. In advance, our new code supports the home-use image or video file format, i.e., jpg, png, or mp4. Thus, it will be more accessible for teachers and students who do not have standard astronomical instruments. The DPSAT measures the stellar light intensity from the time-series still-images or video files from a smartphone or other digital devices. The code can extract video files into sequenced still images, then transform the RGB color space images into greyscale. The light intensity signal of selected pixels is counted with a simple aperture method in time series. It shows the results, for example, the mean signal, standard variation, measured signal as light intensity versus time, and image of light sources. This will be fruitful for low-cost and easily accessible teaching of astrophysics subjects.
Fractional Little-Parks effect in hybrid superconductor-ferromagnet proximity cylinders
Authors: Chamnan N , Nisaisue C , Krunavakarn B
Published: February 2023

We argue that the Little-Parks effect, i.e., the oscillations of the superconducting critical temperature Tc
as a function of the magnetic flux threaded the superconducting cylinder, exhibits the feature of the fractional quantized flux when a ferromagnetic metal filled in the thin-walled superconducting shell, which caused by the exchange interaction. Our analysis is based on the transport-like proximity effect theory in the diffusive regime of Takahashi-Tachiki and shows explicitly that the extremum of Tc
in the vortex state L corresponds to the fractional values of fluxoid, and in particular the fractional flux quantum occurred at the L = 1 vortex state.
First-principles prediction of configurational order-disorder phase transition in Mo2(Ti1−x
V
x
)C2 MXene alloys
Authors: Atthapak Chayanon , Pakornchote Teerachote , Bovornratanaraks Thiti , Maezono Ryo , Ektarawong Annop
Published: February 2023

We investigated the thermodynamic stability of Mo2(Ti1−x
V
x
)C2 MXenes (MTVCs), using the first-principles calculation based on density functional theory and cluster-expansion formalism. Our results suggest that Mo atoms prefer to substitute in the outer metal layers of MTVCs, and such occupying behavior is a crucial factor that determines the thermodynamic stability of MTVCs. On the other hand, Ti and V atoms residing in the inner metal layer of them are predicted to weakly interact with each other and their atomic configuration has a minimal impact on the stability of MTVCs. The transition temperatures between configurationally ordered and disordered phases of MTVCs have been predicted, and the possible existence of configurationally disordered MTVCs has also been discussed.
The temperature dependent surface critical magnetic field (Hc3) of K0.73Fe1.68 Se2 superconductor by semi-anisotropic two band Ginzburg-Landau approach
Authors: Meakniti S , Changjan A , Udomsamuthirun P
Published: February 2023

In this study, we used a two-band Ginzburg-Landau technique to investigate the surface critical magnetic field (Hc3
) of magnetic superconductors, with the first band being an anisotropic superconductor and the second band being an isotropic superconductor. Following the calculation of the 1st Ginzburg-Landau equation, a surface critical magnetic field and its temperature dependent surface critical magnetic field were solved analytically using the variation method. Based on Changjan and Udomsamuthirun’s temperature dependency model, we discovered that fits best with experimental data of K0.73Fe1.68 Se2 superconductor, vicinity of the critical temperature.
Classification of superconducting transition temperature over 150K of metal polyhydrides using support vector machine
Authors: Imchitr V , Pinsook U
Published: February 2023

The search for room-temperature superconductors have shed light on metal polyhydrides as their superconducting transition temperature (TC) vary from a few kelvins to near-room temperatures. One major drawback in the quest for hydrogen-based superconductors is that the calculation of TC through the electron-phonon spectral function consumes large amount of time and computational resources. Here we propose a method of using the support vector machine (SVM) to classify the ranges of TC of the metal polyhydrides without actual calculation of the electron-phonon spectral function. The input variables are chosen based on the effect of hydrogen atoms and the electron localization function (ELF). These set of features can be obtained quickly from the electronics simulations, compare with the actual spectral function calculations. We found that the SVM can classify the superconductors with accuracy over 80 percent with respect to all the metal polyhydrides in the dataset. Our goal of this work is to help screen for the high value of TC of the hydrogen-based compounds, and reduce the time required for the direct calculations of TC.
Structural, mechanical properties and corrosion performance of multilayer Ti doped-DLC/Ti films deposited on low-carbon steel
Authors: Rittihong U , Tunmee S , Supruangnet R , Chingsungnoen A , Poolcharuansin P , Singhapetcharat T , Kiattikomol P , Eknapakul T , Nakajima H , Songsiriritthigul P
Published: February 2023

In this work, the successful preparation of the multilayer Titanium doped diamond-like carbon/Ti (Ti-DLC/Ti) films deposited on low-carbon steel (CS) using hybrid magnetron sputtering (MS) and plasma-enhanced chemical vapor deposition methods has been reported. The Ti and Ti-DLC films were alternately deposited on the CS substrate of up to 4 stacks with an average deposition rate of 16.4±1.7 nm/min and 15.1±1.5 nm/min, respectively, yielding a total thickness of up to 1703 nm. Raman spectroscopic analysis revealed a gradual increase in the I
D/I
G ratio with an increase in Ti layer numbers. Both XPS and NEXAFS results indicate an increase in the C-sp
2 content by increasing the number of Ti layer, which may influence on the hardness reduction. The adhesive properties were found to be improved by adding the number of Ti interlayers between the CS substrate. Moreover, the thicker multilayer films exhibit progressive homogeneity resulting in better corrosion resistance.
Effects of compression on magnetic properties of MnBi prepared by liquid-phase sintering
Authors: Juntree P , Eknapakul T , Pinitsoontorn S , Songsiriritthigul P
Published: February 2023

In this work, the Mn and Bi mixture prepared with and without compression were sintered in a vacuum at 325°C and cooled down naturally to obtain low-temperature phase MnBi. For non-compressed samples, the MnBi content increases with sintering time which could be described by the diffusion process. The average maximum energy product ((BH)max) values were 3.67, 3.05, and 4.77 MGOe for MnBi sintered for 24, 48, and 96 hr, respectively, consistent with their phase identifications. For the compressed samples, the MnBi phase is significantly low in the 24-hr sintered samples compared to the samples sintered for 48 and 96 hr. This resulted in an average (BH)max of 0.43, 3.90, and 3.23 MGOe for the compressed samples sintered for 24, 48 and 96 hr, respectively. The results suggest that compression of the Mn and Bi mixture affects the flow of liquid Bi during sintering and, thus, hinders the formation of MnBi. The effects of the compression were reduced for the prolonged sintered samples, suggesting changes in the internal structure as the sintering proceeded.
Synchrotron Radiation Fourier Transform Infrared (SR-FTIR) spectroscopy in exploring crosslinked chitosan-rice husk bio-composites by gamma irradiation
Authors: Aim-O P , Pamungkas N S , Nawong S , Thamrongsiripak N , Thongphanit S
Published: February 2023

Chitosan biomaterials have widely been used to absorb heavy metals from wastewater and aquatic system due to their low residue generation and the ability to recycle and reuse adsorbents. The chitosan polymer’s high abundance of amino groups also allows for numerous chemical changes to improve its adsorbent characteristics and adsorption capacity. This work synthesized the bio-composite from rice husk and coated it with chitosan solutions. The gamma irradiation had been applied to create the crosslinking chitosan to join two or more intermolecular or intramolecular by a covalent bonding that could give a more rigid structure and potentially a better-defined shape of the material. The Chitosan-Rice Husk bio-composite was irradiated using gamma radiation at a dose of 50, 100, 200, and 400 kGy. Synchrotron Radiation Fourier Transform Infrared (SR-FTIR) Spectroscopy results revealed the induced crosslinking formation of bio-adsorbents after irradiation. The surface topography and composition of samples were demonstrated by using SEM. The natural bioproduct or waste bioproduct is a new promising adsorbent for the removal of heavy metals from industrial wastewater.
Design of dipole magnets for Siam Photon Source II
Authors: Sunwong P , Klinkiew S , Leetha T , Prawanta S , Singthong P , Songsiriritthigul P
Published: February 2023

Two types of dipole magnets are designed for the storage ring of Siam Photon Source II, the second synchrotron light source in Thailand. Magnetic field at the magnet center is 0.87 T, which bends a 3.0 GeV electron beam with the bending radius of 11.532 m and consequently the synchrotron radiation is generated. The first type of dipole magnet is a standard dipole with the magnet gap of 36 mm. The other type is designed for Infrared (IR) beamline with the larger magnet gap of 59 mm to accommodate a wide opening angle of IR radiation. The magnets are designed such that the operating current is the same while the turn number of magnet coils and the magnet gap are allowed to be different. Therefore, a single power supply can be used to excite all dipole magnets in the storage ring which will be connected in series. Magnet modelling and magnetic field calculation are performed in Opera-3D. The magnet poles are shimmed near the edges to improve magnetic field homogeneity to be within the requirement of 2×10−4 within the good field region. Mechanical analysis of magnet structure is performed in SOLIDWORKS and ANSYS where the maximum deformation of 18 - 23 µm is found at the magnet pole and the first-mode natural frequency is higher than 200 Hz.
Considered design and radiation calculation for a compact THz coherent radiation source
Authors: Jummunt Siriwan , Chanwattana Thakonwat , Chunjarean Somjai , Junthong Nawin , Klinkhieo Supat , Pulampong Thapakron , Sunwong Prapaiwan
Published: February 2023

Since the light obtained from the Siam Photon Source (SPS) in Thailand is the high-intensity radiation in only the region of the infrared (IR) to high-energy X-rays, it has great attention in many areas of scientific research and industrial development. In order to increase in the number of users and applications, the terahertz (THz) region covering the frequency range from 0.1 to 10 THz needs to be fulfilled. Therefore, a compact accelerator based free-electron laser or coherent radiation is particularly interesting for providing an intense THz radiation. A 1.6-cell photocathode RF gun is used as an electron source to generate a high-brightness electron beam. The energy of electron beam can be raised up to meet the target of 30 MeV in a linear accelerator (Linac) before moving to a chicane bunch compressor. The THz radiation is produced when a short bunch electron beam propagates through an undulator. In order to achieve the intense narrow-band THz coherent radiation at tunable frequencies between 0.5 THz and 5.0 THz with MW peak power, a THz radiation source needs to be studied and developed. Design of high-power THz radiation source is described in this paper.
Fabrication and development of neutron shielding materials based on natural rubber and boron carbide
Authors: Saenpoowa Jittinun , Ruksakulpiwat Chaiwat , Yenchai Chadet , Kobdaj Chinorat
Published: February 2023

Neutron shielding materials were fabricated based on natural rubber (NR) and boron carbide (B4C) as their main components. Natural rubber, which is abundant in hydrogen, can lower the energy of a neutron. Boron carbide could be utilized as a neutron shielding material due to its high boron content. The shielding materials were fabricated with boron carbide concentrations of 0, 20, 40, 60 parts per hundred rubber (phr), and 50 wt%. Each sample has been fabricated with thicknesses of 5, 10, 15, 20, and 24 mm. The fabricated materials were examined for mechanical and neutron attenuation tests. The Am/Be at the Radiation Measurement Laboratory at the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, was used as a neutron source. The results show that boron carbide has the effect of reducing the toughness while increasing the hardness of NR composites. The NR sample of 50 wt% in boron carbide allows only 14.1% of neutron transmission according to fast neutron attenuation tests, which is similar to that of a sample of the commercial product obtained from a Japanese company. Our findings will later be compared to those of a Monte Carlo N-Particle (MCNP) transport code.
The effect of AGN feedback on shape of dark matter haloes
Authors: Naree Netipon , Muanwong Orrarujee
Published: February 2023

Feedback from active galactic nuclei (AGN) plays an important role on the formation and matter distribution in haloes. We investigate the effect of AGN feedback on shape of dark haloes formed in the EAGLE simulations, and trace the evolution. We select three mass ranges of haloes; low (1011 − 1011.5M⨀), intermediate (1012 − 1012.5M⨀) and high (1013 − 1014.5M⨀) mass, the last range is of small cluster scale. We find the median profile of triaxiality in each mass range at three redshifts (0, 0.27 and 0.87) from two simulations, with and without AGN. The difference of triaxiality in both simulations of low mass haloes at all redshifts is relatively not apparent while the most apparent difference exhibits in high mass haloes. The shape of dark matter haloes in the simulation with AGN is more prolate than that in the simulation without AGN. We also use the ratio between blackhole and dark matter mass, relating to AGN energy output relative to halo potential depth to explain the result. Since the mass ratio between blackhole and dark matter mass in the high and intermediate mass is much larger and extends to the larger radii than that of low mass haloes, the difference is more prominent out to the outer region. We conclude that the shape of dark matter haloes of small cluster scale can be affected by AGN feedback through the evolution. However, this study focuses on an extreme AGN feedback model with a relatively small dynamical range.
Investigation of the periastron shift of star orbit in Hernquist potential
Authors: Sukon B , Chainakun P , Worrakitpoonpon T
Published: February 2023

Understanding of the dynamics of stars around a strong gravitational body such as a supermassive black hole at the centre of galaxies is still incomplete. There is strong evidence suggesting that the orbits of stars in the galactic centre do not follow the Kepler’s laws. In this work, we study the periastron shift from the classical gravitational effect. We select the Hernquist potential function representing a galactic component to examine the rate of change of periastron angular position of a test star. We employ the numerical method to track the orbital dynamics of the test star in that potential. First of all, the periastron shift of the test star is noted and it evolves in the retrograde way. We find that the precession rate varies considerably with the initial speed of the star. In conclusion, we speculate that this effect is non-negligible and it should be accounted when considering the motion of stars in the galactic centre.
Splitting of the atomic hydrogen 21-cm line induced by gravitational waves from a supermassive black hole binary
Authors: Wanwieng N , Chattrapiban N , Watcharangkool A
Published: February 2023

We investigate the characteristic of the hyperfine splitting of a ground-state hydrogen atom subjected to a field of a gravitational wave. In our consideration, hydrogen atoms are in the source’s local wave zone. The interaction between the atoms and the gravitational wave induces the shifts of some energy levels in the hyperfine structure, computed by the first-order perturbation theory. The splitting of energy levels leads to more than one hyperfine transition. Our analysis suggests that a gravitational wave emitted by supermassive black hole binaries could be strong enough to induce a significant effect on the hyperfine splitting. This radio-wave spectrum provides the gravitational-wave signature and thus offers a way of identifying the merger of supermassive black hole binaries.
Machine learning application for dark matter - background classification in JUNO experiment
Authors: Siripak J , Yan Y , Sawangwit U , Sangungsuk N
Published: February 2023

Jiangmen underground neutrino observatory (JUNO) has a potential to indirectly detect dark matter (DM), observing neutrino events from annihilations of DM trapped by the gravitational force in the solar core. Weakly interacting massive particle (WIMP) DM candidate with mass > 4 GeV has significant solar capture rate. In this work, we simulate JUNO neutrino events from the most dominated WIMP annihilation channel,

τ

τ

−

. Given the high-energy neutrinos from massive WIMPs, we extend the neutrino-nucleon interactions in the detector to include quasi-elastic (QE) and deep inelastic scatterings (DIS). The most challenging background events in the energy range above 100 MeV is the atmospheric neutrinos (atmo). The pulse shape discrimination (PSD) method is usually applied to distinguish between DM and atmo. In this work, we apply machine learning (ML) techniques to distinguish between the background (BG) atmo and DM neutrino events. We found that the random forest algorithm gives the best results. Using ML, the accuracy of DM-atmo events classification is 93.8% while similar f1-score could be achieved. On the other hand, only 78.1 % accuracy is obtained using conventional PSD with linear regression (LR). The upper limit for spin-dependent DM-proton cross-section

σ

χ
p

S
D

with the applied ML is 5.84 × 10−40 cm2 for a 10 GeV WIMP DM which is an improvement over the sensitivity of the LR method of by a factor of ∼ 2.8x.
The scientific capabilities of the Evanescent Wave Coronagraph EvWaCo
Authors: Ridsdill-Smith M , Berdeu A , Alagao M A , Buisset C , Awiphan S
Published: February 2023

The Evanescent Wave Coronagraph, EvWaCo, is an in-development prototype coronagraph, designed for use on the 2.4m Thai National Telescope (TNT), in the R and I-band filters. This work examines the astronomical capabilities of EvWaCo using the results from Fourier-analysis simulations. Fourier optics simulations were applied to the EvWaCo prototype to analyse its performance, combining different sources of contrast degradation that will be present in the system. The simulations used for the main analysis assume a good night at the Thai National Observatory (TNO) and include the fitting error, aliasing, measurement noise and lag, providing a radially averaged contrast curve. From the contrast curve, the detection limit, as defined by a minimum signal to noise ratio of 5 for a typical observation time, can be calculated for different primary star magnitudes. The relative fluxes of various binary stars, with a range of spectral classes and separations, were modelled allowing comparison to the EvWaCo detection curves. The photon-noise limited detection curves provide a theoretical baseline for the performance that will be achieved with EvWaCo; they, therefore, give an indication of the types of objects EvWaCo can observe. Along with a broader discussion of observable objects, a number of known binary systems are suggested for observations on the TNT using EvWaCo.
Unidirectional gradient of galactic cosmic ray intensity at different cut-off rigidities and solar magnetic polarities
Authors: Wuttiya C , Yeeram T
Published: February 2023

Energetic charged particles known as Galactic cosmic rays (GCRs) are mostly protons originating from supernova remnants. The solar wind modulates the GCR intensity near-Earth along the solar cycles (SCs) in association with the heliospheric magnetic field (HMF). GCR intensity as observed by the neutron monitor at low, medium, high cut-off rigidities (Pc
) is employed to calculate the South-North (SN) asymmetry of GCR densities (n) of different magnetic polarity states (A) of the HMF. The study covered SCs 22/23, 23/24 and 24/25, during negative and positive states (A < 0 and A > 0). We used the modified correction for secular changes in n to determine the SN asymmetry of n (δnS−N
/n) with respect to the heliospheric current sheet (HCS), a wavy structure dividing the northern and southern HMFs. We found anti-correlation of corrected tilt angle of HCS [α] for Earth’s excursions in helio-latitude

Δ

α

N
−
S

E

with the corrected δnS−N/n, particularly during A < 0 epoch (2004-2008) and A > 0 epoch (2015-2019 not 1996-1998). The results indicate that HCS drift is crucial for asymmetric modulation and latitude gradient of GCR in both epochs. The asymmetric latitudinal gradient [G
⊥] shows strong positive correlation to the consistency between the corrected δnS−N/n and

Δ

α

N
−
S

E

for all epochs and Pc
.
Design and analysis of Hollow-core fiber with anti-resonant structure for Ethylene detection
Authors: Joonmasaa Kwanjira , Sangtawesin Sorawis , Meemon Panomsak , Talataisong Wanvisa
Published: February 2023

An optical fiber for mid-infrared (mid-IR) guidance has long attracted great interest due to its wide range of applications especially in gas sensing. Ethylene gas is one of an important gas, which release from the fruit and flower, owing to their ripening process. Thus, the controlling and detection of ethylene gas is of interest for the storage and exportation of fruits and flowers. Gas detection using the hollow-core optical fiber (HCF) is a promising technique due to it intrinsic micro-channel structure that allows the gas to flow through the HCF for detection propose. Here, a hollow-core anti-resonant fiber (HC-ARF) is designed and optimized for mid-IR guidance for the purpose of ethylene detection. The HC-ARF includes 6 inner tubes which is optimized to achieve a low confinement loss at a wavelength of 3.2 µm (ethylene absorption wavelength). The simulation result shows that a confinement loss of 2 dB/m at the wavelength of 3.2 µm can be achieved when the fiber core diameter is 128 µm and the thickness and the diameter of inner tubes are 2 µm and 92 µm, respectively.
Performance comparison of amplitude-decorrelation and speckle variance algorithms in spectrometer-based OCT angiography
Authors: Kampong W , Saetiew J , Lenaphet Y , Sangtawesin S , Meemon P
Published: February 2023

In this work, optical coherence tomography angiography (OCTA) was implemented on a spectrometer-based spectral domain OCT (SD-OCT) that was built on Michelson interferometer. Three methods of speckle analysis were implemented, i.e. amplitude decorrelation (AD), speckle variance (SV), and speckle to mean variance (SMV). The SMV is an in-house developed algorithm to accommodate the poor signal-to-noise ratio performance of the spectrometer-based SD-OCT. To compare the performance of the implemented algorithms, a flow phantom was constructed by embedding a capillary tube inside a diluted milk gel that represented static tissue. To mimic a blood flow beneath skin, diluted milk was pumped through the capillary tube with speeds of 0.3 to 3.5 mm·s−1 by using a syringe pump system. The performance of each OCTA algorithm, in terms of contrast-to-noise ratio (CNR), were measured and compared. The result shows that SMV algorithm provided the highest relative CNR value of 1.34, which is a 111 % improvement over the performance of SV algorithm.
A Data Enhancement Method toward Real-World Single Image Super-Resolution
Authors: Yang Jiaqi , li Qi , Chen Yueting , Xu Zhihai , Feng Huajun , Wang Jing
Published: February 2023

Introducing convolutional neural networks (CNNs) into single image super-resolution (SISR) has achieved remarkable performance in experimental scenarios over the past decades. However, maintaining constant mapping complexity, most existing CNN-based SISR approaches make it challenging to reconstruct high-quality images in real scenarios because of considerable variation between authentic degradation and simulated degradation. In this paper, to improve SISR models’ capabilities in the real world, we propose a data enhancement method, consisting of frequency domain data augmentation (FDA) and dynamical frequency loss (DFL). By introducing high-resolution images’ frequency information, the FDA enhances the quality and quantity of data, regularizing the model to learn “how” to appropriately apply super-resolution on different frequency components of a given image. In addition, to further strengthen the regularization effect, we design DFL to dynamically assign the loss trade-off hyperparameters of distinct frequency components, guiding the model to allocate computational overhead reasonably. Considering quantitative analysis and visual quality in combination, extensive experiments prove that the proposed enhancement method significantly improves SR models’ capabilities in real scenarios without adding any computational cost to the evaluation procedure.
A Method for Improving the Precision of FOG Scaling Coefficient Calibration Based on the High Precision Turntable
Authors: Zhang Yongfeng , Hu Shuling , Yang Gongliu , Liu Hongwu
Published: February 2023

Aiming at the problem that the calibration accuracy of FOG depends on the precision of turntable, the relationship between the rotation excitation mode calibration and system-level calibration of FOG and the precision of turntable is analyzed. Firstly, the error model of fog is given, and the optimal rotation path is designed based on the principle of rotation excitation mode calibration. The rotation excitation mode calibration and system-level calibration simulation are carried out respectively. The comparison results show that when the precision of the turntable is 1”, the scale coefficient error of the rotation excitation mode calibration is about 60% lower than that of the system calibration. Through further simulation, it is found that the scale coefficient error of the gyroscope calibrated with 10 turns of the turntable is about 50% lower than that of the gyroscope calibrated with 5 turns, and the scale coefficient error can be effectively reduced by increasing the number of turns of the turntable. Finally, the actual experiment is carried out, and it is proved that the calibration accuracy of the rotating excitation mode is higher than that of the system level when the precision of the turntable is higher, which has a certain practical significance for improving the precision of the inertial navigation beacon.
Firefighting Robot Key Structure Design and Analysis
Authors: Xiaolin Ma , Hao Sun , Ran Li , peifeng Zhao , Xin Huang , Xiuzhuo Fu , Mingrui Wang , Skachkov Igor , Yongcheng Liu
Published: February 2023

An intelligent firefighting robot was developed in this paper, and the overall structure and main technical parameters were introduced. The relationships among the parameters on the ramp were studied and analysed, such as the position of the centre of gravity, the length of the track grounding, the width and the slope angle, which provided a reference for the rational configuration of the structural parameters of the robot. Finally, 50kg counterweight was added to the robot according to the analysis structure. And the multi robot finite element analysis was carried out. The results showed that the maximum deformation of the bearing beam is 3.35mm, and the maximum stress value is 92.2MPa, which can meet the use conditions. Finally, the robot was tested on the actual slope, and the results showed that the robot can span 32 degrees of building steps, which was greatly improved the robot’s environmental adaptability.
Free-Standing Multilayer MoS2-BP Heterostructures for High Performance Self-Powered Photodetector
Authors: Zhang Zhihao , Ye Jiaying
Published: February 2023

Phototransistors based on two-dimensional materials such as graphene, transition metal sulfides, and black phosphorus are widely used in in recent years. However, these materials have weak optical absorption, low carrier mobility or poor air stability, which restrict their application in the field of high-sensitivity detection. The inter-stacking of two-dimensional semiconductors can achieve excellent performance, and has promising applications in the field of optoelectronics. The stacking of two-dimensional semiconductors can form van der Waals heterostructures with low defect states and spatial homogeneity, which is an effective way to improve the performance of 2D photodetectors. Based on this, this paper constructs a free-standing multilayer MoS2-BP heterostructure by mechanical exfoliation for high performance self-powered photodetector. The strong space charge region can effectively separate the photogenerated carriers, so it has a good photodetection capability in the self-driven state. Moreover, we analyse and summarize the working mechanism of photodetectors based on 2D materials, and review high sensitivity detectors of recent years based on 2D material heterojunction. Finally, the challenges to further improve the detection sensitivity are pointed out. Thus, our free-standing multilayer MoS2-BP heterostructure propose a useful experience and reference for the future development of self-power photodetectors.
Sparse Volterra Equalizer to Mitigate the Nonlinear Distortion in High Power Budget IM-DD OFDM PON
Authors: Feng Nan , Li Shaobo , Luo Qingsong
Published: February 2023

To improve the power budget for intensity-modulation direct-detection (IM-DD) orthogonal frequency division multiplexing passive optical network (OFDM PON), a high power budget downstream scheme by using the Volterra equalizer in digital signal processing (DSP) processing is proposed in this paper. When the launch power is increased, the subcarrier-to-subcarrier beating interference (SSBI) and other nonlinear distortion are well mitigated by the Volterra equalizer. Moreover, to reduce the complexity of receiver DSP unit, the sparse Volterra equalizer is obtained through optimizing full Volterra equalizer employing orthogonal search method. Simulation and experiment results are presented to evaluate the transmission performance and analyze the distribution of taps of Volterra equalizer under different respects. The results show that the number of tap coefficient of sparse Volterra equalizer is reduced by 60% compared with that of conventional second-order full Volterra equalizer.
Physicochemical, mechanical, dielectric, and biological properties of sintered hydroxyapatite/barium titanate nanocomposites for bone regeneration
Authors: Swain Sujata , Bhaskar Rakesh , Narayanan Kannan Badri , Gupta Mukesh Kumar , Sharma Sonia , Dasgupta Sudip , Han Sung Soo , Kumar Pawan
Published: February 2023

Bone implants fabricated using nanocomposites containing hydroxyapatite (HA) and barium titanate (BT) show osteoconductive, osteoinductive, osteointegration, and piezoelectricity properties for bone regeneration applications. In our present study, HA and BT nanopowders were synthesized using high-energy ball-milling-assisted solid-state reaction with precursors of calcium carbonate and ammonium dihydrogen phosphate, and barium carbonate and titanium oxide powder mixtures, respectively. Hexagonal HA and tetragonal BT phases were formed after calcination at 700 and 1000 °C, respectively. Subsequently, hydroxyapatite/barium titanate (HA/BT) nanocomposites with different weight percentages of HA and BT were prepared by ball-milling, then compacted and sintered at two different temperatures to endow these bioceramics with better mechanical, dielectric, and biological properties for bone regeneration. Microstructure, crystal phases, and molecular structure characterizations of these sintered HA/BT nanocomposite compacts (SHBNCs) were performed using field-emission scanning electron microscopy, x-ray diffraction, and Fourier-transform infrared spectroscopy, respectively. Bulk density was evaluated using the Archimedes method. HA/BT nanocomposites with increased BT content showed enhanced dielectric properties, and the dielectric constant (ϵr) value for 5HA/95BT was ∼182 at 100 Hz. Mechanical properties such as Vicker’s hardness, fracture toughness, yield strength, and diametral tensile strength were also investigated. The hemolysis assay of SHBNCs exhibited hemocompatibility. The effect of these SHBNCs as implants on thein vitrocytocompatibility and cell viability of MG-63 osteoblast-like cells was assessed by MTT assay and live/dead staining, respectively. 15HA/85BT showed increased metabolic activity with a higher number of live cells than BT after the culture period. Overall, the SHBNCs can be used as orthopedic implants for bone regeneration applications.
Temporal hydrological drought clustering varies with climate and land-surface processes
Authors: Brunner Manuela I , Stahl Kerstin
Published: February 2023

Recurrent hydrological droughts (streamflow deficits) are highly impactful and challenge water management. Regional studies have provided some evidence of drought-rich periods at specific time scales. However, it is yet unclear where and when droughts cluster in time. Here, we test for significant temporal hydrological drought clustering at subseasonal to multi-year time scales in different climate zones around the world using two different clustering metrics, i.e. the dispersion index and Ripley’s K. We find that (1) only 10% of the catchments show temporal hydrological drought clustering, (2) hydrological droughts cluster from seasonal to 3-year time scales with clustering being strongest at an annual time scale; (3) arid catchments with a low snow fraction are most prone to temporal drought clustering; and (4) temporal clustering is more pronounced for hydrological than for meteorological droughts. These results suggest that besides climatic drivers, land-surface processes importantly influence the temporal clustering behavior of hydrological droughts.
Rapid synthesis of nano-TiC particles by microwave heating method
Authors: Bai Shuang , Guan Li , Dong Binbin , Min Zhiyu , Gao Qiancheng , Li Mingliang , Chen Jiahui , Zhou Xuemeng , Zhang Yuanyuan , Wang Gaoyuan , Zhang Rui
Published: February 2023

Nanosize titanium carbide (TiC) particles were fabricated by microwave heating at 1100 °C for 10 min using carbon and tetrabutyl titanate as raw materials. The as-sintered precursor was prepared using the sol-gel method. The phase composition, morphology and microwave heating behavior of the heated products were investigated. It was found that TiC particles can be synthesized in a closed capsule of SiO2 with the combined action of high temperature and gaseous products. TiC particles with an average diameter of 50 nm can be synthesized through microwave heating at 1100 °C for 10 min. Higher temperature and longer holding time would lead to re-oxidation and the coalescence of as-formed TiC products. This work demonstrates that this rapid and low-temperature preparation method of nanosize TiC particles has potential application for industrial production.
Influence of filler wire on metallurgical, mechanical, and corrosion behaviour of 430 ferritic stainless steel using a fusion welding process
Authors: Bansod Ankur , Shukla Sourabh , Gahiga Gabriel , Verma Jageshvar
Published: February 2023

The advantage of ferritic stainless steels (FSS’s) over austenitic stainless steels is that they are less expensive alloys. This is due to low or negligible nickel in its alloying element which makes the steel affordable. This type of steel is highly recommended against chloride attack and is also machinable to produce various components for engineering applications. This study examines the effect of various fillers on 430 ferritic stainless steel (FSS). The austenitic (308) and ferritic (410) grades of filler were used to study the weldability, microstructure, mechanical properties, and corrosion resistance using tungsten inert gas welding. The findings showed the emergence of various complex phases in both the weld sample. The sample welded with 410 filler shows acicular ferrite, martensite and austenite. Whereas, austenite and vermicular ferrite are observed in the sample welded with 308 filler. Based on compositions and solidification modes, the mechanical properties of welded joints also vary. It was found that ferritic mode solidified welds dominated in terms of qualities, which was found in 410 filler. In the chloride solution, the behaviour of the pitting corrosion resistance of each weld varied. The sample welded with 410 was superior corrosion resistance. This is due to more δ-ferrite in the weld sample. Whereas, 308 showed poorer resistance against the simulated seawater solution. In 410 welds, a greater degree of sensitization was observed, as compared to 308 welds.
Inherent internal p-n junction assisted single layered n-type iron pyrite solar cell
Authors: Gohri Shivani , Madan Jaya , Mohammed Mustafa K A , Pandey Rahul
Published: February 2023

The high absorption coefficient and low cost with plentiful availability make the material iron pyrite (FeS2) promising for solar cell applications. However, their efficiency in the literature is still around 2.8% due to their low VOC. The presence of an acceptor-type surface inversion layer (SIL) with a significant band gap (0.56 eV–0.72 eV) is the main cause of this low performance. A detailed study considering these two parameters is not available in the literature to relate device performance to underlying phenomena. Therefore, a comprehensive analysis of the band gap and doping variation of SIL was performed in this article to explore the efficiency potential of FeS2 solar cells. The results showed that SIL with a low bandgap is highly undesirable, and it is recommended to fabricate SIL with a higher band gap of 0.72 eV and a doping of 1019 cm−3 in the laboratory to achieve a conversion efficiency of 5.36%. It was also confirmed that FeS2-based solar cells without a SIL layer have the potential to deliver 10.3% conversion efficiency. The results reported in this study will pave the way for underestimating the workings of iron pyrite solar cells and developing highly efficient FeS2 solar cells.
Application of reinforcement learning in planning and operation of new power system towards carbon peaking and neutrality
Authors: Sun Fangyuan , Wang Zhiwei , Huang Junhui , Diao Ruisheng , Zhao Yingru , Lan Tu
Published: February 2023

To mitigate global climate change and ensure a sustainable energy future, China has launched a new energy policy of achieving carbon peaking by 2030 and carbon neutrality by 2060, which sets an ambitious goal of building NPS with high penetration of renewable energy. However, the strong uncertainty, nonlinearity, and intermittency of renewable generation and their power electronics-based control devices are imposing grand challenges for secure and economic planning and operation of the NPS. The performance of traditional methods and tools becomes rather limited under such phenomena. Together with high-fidelity modeling and high-performance simulation techniques, the fast development of AI technology, especially RL, provides a promising way of tackling these critical issues. This paper first provides a comprehensive overview of RL methods that interact with high-fidelity grid simulators to train effective agents for intelligent, model-free decision-making. Secondly, three important applications of RL are reviewed, including device-level control, system-level optimized control, and demand side management, with detailed modeling and procedures of solution explained. Finally, this paper discusses future research efforts for achieving the goals of full absorption of renewable energy, optimized allocation of large-scale energy resources, reliable supply of electricity, and secure and economic operation of the power grid.
An RRAM retention prediction framework using a convolutional neural network based on relaxation behavior
Authors: Zhang Yibei , Zhang Qingtian , Qin Qi , Zhang Wenbin , Xi Yue , Jiang Zhixing , Tang Jianshi , Gao Bin , Qian He , Wu Huaqiang
Published: February 2023

The long-time retention issue of resistive random access memory (RRAM) brings a great challenge in the performance maintenance of large-scale RRAM-based computation-in-memory (CIM) systems. The periodic update is a feasible method to compensate for the accuracy loss caused by retention degradation, especially in demanding high-accuracy applications. In this paper, we propose a selective refresh strategy to reduce the updating cost by predicting the devices’ retention behavior. A convolutional neural network-based retention prediction framework is developed. The framework can determine whether an RRAM device has poor retention that needs to be updated according to its short-time relaxation behavior. By reprogramming these few selected devices, the method can recover the accuracy of the RRAM-based CIM system effectively. This work provides a valuable retention coping strategy with low time and energy costs and new insights for analyzing the physical connection between the relaxation and retention behavior of the RRAM device.
PI3P regulates multiple stages of membrane fusion
Authors: Orr Amy , Wickner William
Published: February 2023

Using reconstituted fusion with all purified proteins and defined lipids, four targets for PI3P regulation are reported: recruitment of the Qc-SNARE, trans-SNARE assembly between membranes, protection of SNARE complexes from the chaperones Sec17 and Sec18 by the conserved tethering complex HOPS, and fusion per se after tethering.
Cooking Interventions for Improving Diet Quality Among Black Americans: A Randomized Controlled Trial
Authors: Kramer Emily B , Knight Erik L , Bryan Angela D
Published: February 2023

Background

Non-Hispanic Black Americans experience the highest, and most rapidly increasing, rates of obesity. Despite evidence that this is at least somewhat related to poor diet quality, we have yet to identify effective interventions for improving diet quality long-term. Restrictive diets can be ineffective and often harmful. In contrast, there is a well-established connection between home cooking and lower body mass index, better diet quality, and improved health.

Purpose

The present study applied the Theory of Planned Behavior (TPB) to examine the effect of an intervention delivering cooking instruction, rather than nutrition information, on beliefs, attitudes, and behaviors pertaining to diet quality and cooking among Black adults in the USA.

Methods

An online sample of Black Americans (N = 147), ages 18–76 (M = 30.69, SD = 10.42) were recruited via Prolific and randomized to view either a cooking tutorial video or a “standard of care” control webpage followed by either an implementation intentions (II) writing activity or a “freestyle” control writing activity. Cognitions and behavior related to healthy eating and cooking were measured at baseline, post-intervention, and 1-week follow-up.

Results

Results of mixed-effects modeling indicated that participants randomized to the video condition reported significantly greater post-intervention intentions to cook (p < .001), which positively correlated with cooking behavior over the subsequent week (p < .01). There was no effect of the II intervention on subsequent-week behavior (ps > .413). Importantly, 75% (n = 105) indicated experiencing food insecurity at the time of data collection.

Conclusions

These results highlight a promising pathway for improving nutrition and diet-related health outcomes among Black Americans while highlighting that any intervention must account for food insecurity in this population.
New horizons in managing older cancer survivors: complexities and opportunities
Authors: Mislang Anna R A , Mangoni Arduino A , Molga Angela , Jena Swatee , Koczwara Bogda
Published: February 2023

Older adults represent a growing population amongst cancer survivors who require specific consideration given the complex and largely unknown interactions between cancer-related concerns and age-related conditions. The increasing use of geriatric assessment (GA) has enabled oncologists to appropriately assess older patients’ overall health status, personalise anti-cancer treatment and improve survival. However, whilst current research and practice focus on improving the management of older adults with cancer in the acute setting, the progress in the field of survivorship research in geriatric oncology is lagging. As cancer survivorship is a continuum, planning for a healthy survivorship should start at the time of cancer diagnosis. GA can play an important role in identifying potential survivorship issues and optimising delivery of survivorship care. A goal-directed, patient-focused geriatric survivorship care plan that involves a multidisciplinary team provides a framework for a personalised delivery of survivorship care in this patient group and there is a need for tailored interventions that support self-management and care integration. Research on the impact of cancer and its treatment on geriatric-specific outcomes needs to be prioritised through global initiatives to encompass a diverse and heterogenous population of adult cancer survivors.
Diverse effects of gaze direction on heading perception in humans
Authors: Gao Wei , Lin Yipeng , Shen Jiangrong , Han Jianing , Song Xiaoxiao , Lu Yukun , Zhan Huijia , Li Qianbing , Ge Haoting , Lin Zheng , Shi Wenlei , Drugowitsch Jan , Tang Huajin , Chen Xiaodong
Published: February 2023

Gaze change can misalign spatial reference frames encoding visual and vestibular signals in cortex, which may affect the heading discrimination. Here, by systematically manipulating the eye-in-head and head-on-body positions to change the gaze direction of subjects, the performance of heading discrimination was tested with visual, vestibular, and combined stimuli in a reaction-time task in which the reaction time is under the control of subjects. We found the gaze change induced substantial biases in perceived heading, increased the threshold of discrimination and reaction time of subjects in all stimulus conditions. For the visual stimulus, the gaze effects were induced by changing the eye-in-world position, and the perceived heading was biased in the opposite direction of gaze. In contrast, the vestibular gaze effects were induced by changing the eye-in-head position, and the perceived heading was biased in the same direction of gaze. Although the bias was reduced when the visual and vestibular stimuli were combined, integration of the 2 signals substantially deviated from predictions of an extended diffusion model that accumulates evidence optimally over time and across sensory modalities. These findings reveal diverse gaze effects on the heading discrimination and emphasize that the transformation of spatial reference frames may underlie the effects.