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Structural, magnetic, and electronic properties of a GdAsSe single crystal: Experimental and theoretical studies

Physical Review B 2024年第18期109卷 184420-184420页

作者： R. Kalaivanan Balaji Venkatesan B. Dundi Sri Chandana Rajesh Kumar Ulaganathan G. Senthil Murugan K. Moovendaran Joydev Khatua Li-Hsin Su W. Zhou Xiaofeng Xu Chia-Seng Chang Tien-Ming Chuang Yoshiyuki Iizuka I. Panneer Muthuselvam Horng-Tay Jeng Kwang-Yong Choi Raman Sankar Institute of Physics Academia Sinica Taipei 10617 Taiwan Department of Physics National Taiwan University Taipei 10617 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica and National Taiwan University Taipei 11529 Taiwan Department of Physics School of Basic and Applied Sciences Central University of Tamil Nadu Neelakudi Thiruvarur 610005 Tamil Nadu India Department of Physics Sungkyunkwan University Suwon 16419 Republic of Korea Department of Physics National Tsing Hua University Hsinchu 30013 Taiwan Department of Electro Physics National Yang Ming Chiao Tung University Hsinchu 300093 Taiwan School of Electronic and Information Engineering Changshu Institute of Technology Changshu 215500 China Department of Applied Physics Zhejiang University of Technology Hangzhou 310023 China Institute of Earth Sciences Academia Sinica Taipei 10617 Taiwan Department of Physics (MMV) Banaras Hindu University Varanasi 221005 Uttar Pradesh India Physics Division National Center for Theoretical Sciences Taipei 10617 Taiwan

We report high-quality single-crystal growth, x-ray diffraction, magnetic susceptibility [χ(T,H)], magnetization [M(H)], heat capacity [CP(T,H)], electrical resistivity [ρ(T,H)], and electron spin resonance (ESR) measurements of GdAsSe as functions of temperature and magnetic field. We identify an antiferromagnetic phase transition at TN∼11.9±0.2 K and construct magnetic phase diagrams for H||ab and H||c axes based on the χ(T,H) and CP(T,H) data. Isothermal M(H) curves along the H||ab direction at 3 K exhibit a field-induced spin orientation at HC∼3.78T. Both M(H) and χ(T,H) indicate an easy-plane-type anisotropy. The Curie-Weiss analysis of the high-temperature paramagnetic χ(T) yields a negative Weiss temperature, suggesting dominant antiferromagnetic interactions between the Gd ions. Magnetic entropy reaches 83% of R ln8 at TN. The presence of residual entropy above TN and the persistence of ESR critical broadening up to ∼3TN alludes to a degree of magnetic frustration in the studied material. The ρ(T) data above TN is well fitted to the Bloch-Grüneisen theory for metals. Further, density functional theory calculations reveal an antiferromagnetic ground state where the Gd atoms are coupled ferromagnetically in the ab plane and antiferromagnetically along the c axis.

关键词： Magnetic anisotropy Magnetic coupling Magnetic interactions Magnetic order Magnetism

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Calibration of nuclear charge density distribution by back-propagation neural networks

arXiv

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arXiv 2022年

作者： Yang, Zu-Xing Fan, Xiao-Hua Naito, Tomoya Niu, Zhong-Ming Li, Zhi-Pan Liang, Haozhao RIKEN Nishina Center Wako351-0198 Japan School of Physical Science and Technology Southwest University Chongqing400715 China RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program Wako351-0198 Japan Department of Physics Graduate School of Science The University of Tokyo Tokyo113-0033 Japan School of Physics and Optoelectronic Engineering Anhui University Hefei230601 China

Based on the back-propagation neural networks and density functional theory, a supervised learning is performed firstly to generate the nuclear charge density distributions. The charge density is further calibrated to the experimental charge radii by a composite loss function. It is found that, when the parity, pairing, and shell effects are taken into account, about 96% of the nuclei in the validation set fall within two standard deviations of the predicted charge radii. The calibrated charge density is then mapped to the matter density, and further mapped to the binding energies according to the Hohenberg-Kohn theorem. It provides an improved description of some nuclei in both binding energies and charge radii. Moreover, the anomalous overbinding in 48Ca implies the existence of an indispensable beyond-mean-field effect. Copyright © 2022, The Authors. All rights reserved.

关键词： Charge density

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Assessment of sources and health risks of heavy metals in metropolitan household dust among preschool children: The LEAPP-HIT study

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Journal of Environmental Management 2024年 352卷 120015页

作者： Kao, Chi-Sian Wang, Ying-Lin Jiang, Chuen-Bin Tai, Pei-Ju Chen, Yi-Hua Chao, Hsing-Jasmine Lo, Yu-Chun Hseu, Zeng-Yei Hsi, Hsing-Cheng Chien, Ling-Chu School of Public Health College of Public Health Taipei Medical University Taipei Taiwan Graduate Institute of Environmental Engineering National Taiwan University Taipei Taiwan Department of Pediatric Gastroenterology Hepatology and Nutrition MacKay Children's Hospital Taipei Taiwan Department of Medicine MacKay Medical College SanZhi District New Taipei City Taiwan Neuroscience Research Center Taipei Medical University Taipei Taiwan Ph.D. Program in Medical Neuroscience College of Medical Science and Technology Taipei Medical University Taipei Taiwan Department of Agricultural Chemistry National Taiwan University Taipei Taiwan Nutrition Research Center Taipei Medical University Hospital Taipei Taiwan

The most common construction material used in Taiwan is concrete, potentially contaminated by geologic heavy metals (HMs). Younger children spend much time indoors, increasing HM exposure risks from household dust owing to their behaviors. We evaluated arsenic (As), cadmium (Cd), and lead (Pb) concentrations in fingernails among 280 preschoolers between 2017 and 2023. We also analyzed HM concentrations, including As, Cd, Pb, chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn), in 90 household dust and 50 road dust samples from a residential area where children lived between 2019 and 2021 to deepen the understanding of sources and health risks of exposure to HMs from household dust. The average As, Cd, and Pb concentrations in fingernails were 0.12 ± 0.06, 0.05 ± 0.05, and 0.95 ± 0.77 μg/g, respectively. Soil parent materials, indoor construction activities, vehicle emissions, and mixed indoor combustion were the pollution sources of HMs in household dust. Higher Cr and Pb levels in household dust may pose non-carcinogenic risks to preschoolers. Addressing indoor construction and soil parent materials sources is vital for children's health. The finding of the present survey can be used for indoor environmental management to reduce the risks of HM exposure and avoid potential adverse health effects for younger children. © 2024 Elsevier Ltd

关键词： Heavy metals

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Nanoslot-Induced Ultrastrong Phonon-Photon and Phonon-Phonon Coupling in Hybrid Organic-Inorganic Perovskites

Nanoslot-Induced Ultrastrong Phonon-Photon and Phonon-Phonon...

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Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： Dasom Kim Jin Hou Geon Lee Ayush Agrawal Sunghwan Kim Hao Zhang Di Bao Andrey Baydin Wenjing WU Fuyang Tay Shengxi Huang Daivd Hagenmüller Elbert E. M. Chia Dai-Sik Kim Minah Seo Aditya D. Mohite Junichiro Kono Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Department of Electrical and Computer Engineering Rice University Houston TX USA Department of Materials Science and NanoEngineering Rice University Houston TX USA Sensor System Research Center Korea Institute of Science and Technology Seoul Republic of Korea Department of Physics and Astronomy Seoul National University Seoul Republic of Korea Department of Chemical and Biomolecular Engineering Rice University Houston TX USA Department of Physics Long-wavelength Nanotechnology Laboratory Quantum Photonics Institute Ulsan National Institute of Science and Technology (UNIST) Ulsan Republic of Korea Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore Smalley-Curl institute Rice University Houston TX USA CESQ-ISIS (UMR 7006) Universite de Strasbourg and CNRS Strasbourg France KU-KIST Graduate School of Converging Science and Technology Korea University Seoul Republic of Korea Department of Physics and Astronomy Rice University Houston TX USA

Methods for harnessing vibrational states are desired for phonon-based technologies. We realized ultrastrong coupling of two phonon modes in perovskite materials induced by ultrastrong coupling with a common photonic ... 详细信息

ISBN: (数字)9798350372076

ISBN: (纸本)9798350372083

关键词： Couplings Phonons Laser modes Perovskites Electro-optical waveguides Photonics

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Blue micro-LED with a red/green blended polymer film for 3.5-Gbps visible light communication employing adaptive SNR-Flattening Algorithm

Next Nanotechnology

引用

Next Nanotechnology 2024年 5卷

作者： Ho, Pin-Wei Cheng, Chih-Hsien Liao, Yu-Sheng Chi, Yu-Chieh Sadhu, Annada Sankar Matsumoto, Atsushi Akahane, Kouichi Chen, Li-Yin Kuo, Hao-Chung Lin, Gong-Ru Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering National Taiwan University Taipei 106319 Taiwan National Institute of Information and Communications Technology Koganei Tokyo 184-8795 Japan SANWAY OPTOELECTRONICS TECH. CORP New Taipei City 235601 Taiwan Department of Photonics Institute of Electro-Optical Engineering College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan International Ph.D. Program in Photonics (UST) College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Hsinchu 30010 Taiwan Semiconductor Research Center Hon Hai Research Institute Taipei 11492 Taiwan NTU-Tektronix Joint Research Center Tektronix Inc. and National Taiwan University Taipei 106319 Taiwan

By the semipolar blue single GaN μ-LED and blended Ir(piq)2(acac) + CC-MP5 polymer thin film color converter, a high-speed white-light μ-LED-based system is built up for the applications of short-distance VLC. The characteristics and properties of both devices are analyzed to understand the requirements for transmission and illumination. By selecting the growing orient, the influence of QCSE is reduced in this GaN μ-LED. Meanwhile, possessing the low reflection characteristic, it is beneficial for signal modulation. For the polymer thin film color converter with a lifetime of 7.8 ns, low surface reflection and high conversion efficiency are thought of good properties. Color-converted cool white light has a CCT of around 7000 K and high color accuracy with a CRI of about 90. The APD-combined frequency responses of the GaN μ-LED and GaN μ-LED + polymer are measured as 750 MHz and 600 MHz, respectively. After the optimization by utilizing the adaptive SNR-flattening pre-emphasis algorithm, the transmission performance of the white-light μ-LED is significantly promoted. For NRZ-OOK encoding, a 1.4 Gbps 0.15-m free-space transmission is achieved with a rising time of 656.33 ps, a falling time of 493.32 ps, and a Q-factor of 4.75. Besides, in more advanced data formats, the performance of this white-light μ-LED can be better highlighted. For the same 0.15-m free-space VLC, a high-speed 3 Gbps broadband 8-QAM-OFDM transmission is fulfilled with an EVM of 23.9%, an average SNR of 12.5, and a BER below 3.8 × 10^-3;while to the best of our knowledge, a record 3.5 Gbps BL-DMT transmission is implemented as well. This white-light μ-LED can also be integrated into large-scale arrays for multi-functional VLC applications. © 2024 The Authors

关键词： Adaptive SNR-Flattening algorithm Blue micro-LED Red/Green blended polymer Visible light communication

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Scalable Metagrating for Efficient Ultrasonic Focusing

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Physical Review Applied 2021年第6期16卷 064014-064014页

作者： Yan Kei Chiang Li Quan Yugui Peng Shahrokh Sepehrirahnama Sebastian Oberst Andrea Alù David A. Powell School of Engineering and Information Technology University of New South Wales Canberra ACT 2610 Australia Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Centre for Audio Acoustics and Vibration University of Technology Sydney Broadway NSW 2007 Australia Physics Program Graduate Center City University of New York New York New York 10016 USA

Acoustic metalenses have been pursued over the past decades due to their pivotal role in a wide variety of applications. Recent research efforts have demonstrated that, at ultrasonic regimes, acoustic levitation can be realized with standing waves, which are created by the interference between incoming and reflected focused waves. However, the conventional gradient-metasurface approach to focus ultrasonic waves is complex, leading to poor scalability. In this work, we propose a design principle for ultrasonic metalenses, based on metagratings—arrays of discrete scatters with coarser features than gradient metasurfaces. We achieve beam focusing by locally controlling the excitation of a single diffraction order with the use of metagratings, with geometry adiabatically varying over the lens aperture. We show that our metalens can effectively focus impinging ultrasonic waves to a focal point with a full width at half maximum of 0.364 of the wavelength. The focusing performance of the metalens is demonstrated experimentally, validating our proposed approach. This metagrating approach to focusing can be adopted for different operating frequencies by scaling the size of the structure, which has coarse features suitable for high-frequency designs, with potential applications ranging from biomedical science to nondestructive testing.

关键词： Acoustic measurements Acoustic metamaterials Acoustic modeling Acoustic wave phenomena Beam optics Ultrasonics Bloch-Floquet theorem Ultrasound techniques

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Deactivation/Regeneration Studies in Structured Monolithic Ni-Based Catalysts Applied in Dry Reforming of Methane

SSRN

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SSRN 2022年

作者： de Araújo, Ítalo R.S. Ribeiro, André T.S. Garcia, Ramón R.P. Sales, Deivson C.S. Almeida, Luciano C. Department of Chemical Engineering Technology and Geoscience Center Federal University of Pernambuco PE Recife50740-521 Brazil Polytechnic School of Pernambuco University of Pernambuco Rua Benfica 455 Madalena PE Recife50720-001 Brazil Materials Science and Engineering Graduate Program Federal University of Piauí PI Teresina Brazil Federal Rural University of Pernambuco Academic Unit of Cabo de Santo Agostinho PE Cabo de Santo Agostinho Brazil

In this work, the Ni/γ-Al2O3 (Ni/Al) and Ni/LA2O3-γ-Al2O3 (Ni/La-Al) catalysts were synthesized by the all-in-one method and used in the Dry Reforming of Methane (DRM). The catalysts were characterized and a smaller Ni crystallite size for the La-promoted catalyst was observed. The effects of the feed ratio (CH4:CO2), the use of La as a promoter of the catalyst support, and the use of the structured system in DRM reaction were investigated. Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were applied to investigate the catalytic deactivation effects. The deactivation of the structured catalysts was also evaluated by applying different weight hourly space velocities (WHSV): 20, 30, and 40 L gcat-1 h-1. Besides that, the regeneration of the catalysts was developed through the comparison of the treatment with CO2 and H2 atmospheres. The catalytic study of the powder samples showed that the lower the CH4:CO2 ratio the higher reactants conversion for both catalysts. It was also noted that the CH4:CO2 feed ratio of 4 provided a conversion 10 % higher for the Ni/La-Al catalyst in comparison with the Ni/Al catalyst. The analogy between the powder and structured systems implied greater conversion for the structured system. Furthermore, the greater and the lower deactivation of the structured systems were identified for the WHSV values of 40 and 20 L gcat-1 h-1, respectively. Finally, the regeneration treatment with CO2 showed to be more efficient than the treatment with H2 © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

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Development of low-cost tool for assessing chlorophyll content using the mobile-phone camera

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AIP Conference Proceedings 2024年第1期3086卷

作者： Wahyu Nurkholis Hadi Syahputra Chatchawan Chaichana Ramnarong Wanison Braja Manggala Graduate Master’s Degree Program in Energy Engineering Department of Mechanical Engineering Faculty of Engineering Chiang Mai University Chiang Mai 50200 Thailand Energy Technology for Environment Research Center Department of Mechanical Engineering Faculty of Engineering Chiang Mai University Chiang Mai 50200 Thailand Department of Mechanical Engineering Faculty of Engineering Chiang Mai University Chiang Mai 50200 Thailand

Leaves can be used to assess the health of a plant. The chlorophyll content and nitrogen status of plants might be used to assess plant health. Chlorophyll content of plant leaves is measurable in the laboratory using dimethyl sulfoxide or the Kjeldahl technique. These destructive investigations of plant tissues accurately evaluates chlorophyll concentration and nitrogen status. However, this procedure is costly and time-consuming. Using a SPAD instrument, non-destructive chlorophyll measurements were performed. However, the price of the instrument is high. This research intends to develop a technique for detecting chlorophyll content using a smartphone’s built-in camera. The approach used is an advancement of ground-based remote sensing technology. The object of this research is maize. An RGB camera on a mobile phone was used to gather data on the greenness level of the leaf. Concurrently, the SPAD value was measured to determine the chlorophyll content. In this study, there were three primary phases, capturing leaf images with geotags, leaf image processing, and vegetation index (VIs) analysis. This research demonstrated that a mobile camera has potential as a tool for measuring chlorophyll content depending on the level of leaf greenness. Additionally, the GPS function on each data provides the chlorophyll distribution in a field.

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Polarization entanglement enabled by orthogonally stacked van der Waals NbOCl2 crystals

arXiv

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arXiv 2024年

作者： Guo, Qiangbing Wu, Yun-Kun Zhang, Di Zhang, Qiuhong Guo, Guang-Can Alù, Andrea Ren, Xi-Feng Qiu, Cheng-Wei Department of Electrical and Computer Engineering National University of Singapore Singapore Singapore Centre for Advanced 2D Materials Graphene Research Centre National University of Singapore Singapore Singapore CAS Key Laboratory of Quantum Information CAS Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China Hefei China Hefei National Laboratory University of Science and Technology of China Hefei China Photonics Initiative Advanced Science Research Center City University of New York New York United States Physics Program Graduate Center City University of New York New York United States The Key Laboratory of Weak-Light Nonlinear Photonics Ministry of Education School of Physics TEDA Applied Physics Institute Nankai University Tianjin China School of Chemistry and Materials Science Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou China

Polarization entanglement holds significant importance for photonic quantum technologies. Recently emerging subwavelength nonlinear quantum light sources, e.g., GaP and LiNbO3 thin films, benefiting from the relaxed phase-matching constraints and volume confinement, has shown intriguing properties, such as high-dimensional hyperentanglement and robust entanglement anti-degradation. Van der Waals (vdW) NbOCl2 crystal, renowned for its superior optical nonlinearities, has emerged as one of ideal candidates for ultrathin quantum light sources [Nature 613, 53 (2023)]. However, polarization-entanglement is inaccessible in NbOCl2 crystal due to its unfavorable nonlinear susceptibility tensor. Here, by leveraging the twist-stacking degree of freedom inherently in vdW systems, we showcase the preparation of tunable polarization entanglement and quantum Bell states. Our work not only provides a new and tunable polarization-entangled vdW photon-pair source, but also introduces a new knob in engineering the entanglement state of quantum light at the nanoscale. © 2024, CC BY-NC-ND.

关键词： Van der Waals forces

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Sustainability assessment of groundwater in south-eastern parts of the western region of Ghana for water supply

Cleaner Water

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Cleaner Water 2024年 1卷

作者： Ernest Biney Bernard Akwasi Mintah Ernest Ankomah Albert Elikplim Agbenorhevi Daniel Buston Yankey Ernestina Annan Department of Geomatic Engineering Kwame Nkrumah University of Science and Technology University Post Office Box PMB Kumasi Ghana WASCAL Graduate Research Programme on Climate Change and Land Use Department of Civil Engineering Kwame Nkrumah University of Science and Technology Kumasi Ghana Department of Geological Engineering University of Mines and Technology Tarkwa Ghana Graduate Research Program on Climate Change and Water Resources West African Science Service Center on Climate Change and Adapted Land Use (WASCAL) University of Abomey-Calavi Benin

The study assessed the physicochemical and biological properties of selected groundwater sources in the Southeastern part of the Western Region, to assess the impact on water quality and health risk. The Piper Trilinear plot was used to categorize the water samples into water types based on the dominant anion and cation concentrations. Statistical analysis (One way ANOVA and two sample t-test) was used to determine the sources of variation in the data at 95% confidence interval. The Water Quality Index (WQI) and Hazard Quotient (HQ) were used to estimate the water quality and health risk respectively. TDS and turbidity were above the acceptable WHO guidelines in 16.7% of the samples with a mildly acidic pH in 83.3% of the water samples. Also, 91.7% of the water samples were contaminated with total coliform (TC) and 25% with e-coli. Generally, the groundwater samples were dominated by Ca 2+ and HCO 3- ion water types. The variations between parameters were found not significant for all the parameters (p>0.05). Water samples in the North are of good quality with a mean WQI of 96, but of poor quality in the South with a mean WQI of 144.6. HQ values for all the samples were less than 0.1, suggesting less harmful impacts of the heavy metal concentrations on human health. Overall, the results showed the presence of heavy metals in the groundwater sources sampled, however in quantities with low health risks either through oral or dermal channels. Groundwater within the communities is good for domestic purposes but needs treatment for drinking. To improve upon the study, it is recommended that further studies consider a higher number of samples and include other accessible groundwater stations where possible.

关键词： Health Risk Assessment Groundwater GIS Trace elements Water Quality Index

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