Article
Chemistry, Multidisciplinary
Zhongbo Yang, Dongyun Tang, Jiao Hu, Mingjie Tang, Mingkun Zhang, Hong-Liang Cui, Lihua Wang, Chao Chang, Chunhai Fan, Jiang Li, Huabin Wang
Summary: A graphene-mediated THz scattering-type scanning near-field optical microscope is developed for direct imaging of single proteins, demonstrating that a graphene substrate with high THz reflectivity and atomic flatness provides high THz contrast against protein molecules. The use of an optimized length platinum probe enhances the amplitude of scattered THz near-field signals, allowing the topographical and THz scattering images of individual IgG and ferritin molecules with a few nanometers in size to be obtained simultaneously. This strategy opens up new avenues for imaging single biomolecules with THz.
Article
Physics, Multidisciplinary
Feng Long-Cheng, Du Chen, Yang Sheng-Xin, Zhang Cai-Hong, Wu Jing-Bo, Fan Ke-Bin, Jin Biao-Bing, Chen Jian, Wu Pei-Heng
Summary: In this paper, a real-time near-field high-resolution THz spectral imaging system is designed and built. The system can switch between large beam THz imaging and tight-focusing THz imaging. The performance of the system is analyzed by measuring and studying micromachining samples, showing its superiority in spatial resolution and imaging speed.
ACTA PHYSICA SINICA
(2022)
Article
Nanoscience & Nanotechnology
Angela Pizzuto, Enrique Castro-Camus, William Wilson, Wonsik Choi, Xiuling Li, Daniel M. Mittleman
Summary: The combination of s-SNOM techniques with short pulse durations has opened new possibilities in characterizing nanosystems with high spatial and temporal resolution, particularly in the long wavelength regime.
Article
Astronomy & Astrophysics
Kazuki Ikeda, Dmitri E. Kharzeev, Yuta Kikuchi
Summary: The study shows that in the (1 + 1)-dimensional massive Schwinger model with a theta-term, a sharp maximum in the topological susceptibility is observed near the parity-breaking critical point where theta = pi and the fermion mass to coupling ratio is approximately 0.33. This phenomenon is interpreted as being related to the growth of critical fluctuations near the critical point, and analogies are drawn between the massive Schwinger model, QCD near the critical point, and ferroelectrics near the Curie point.
Article
Chemistry, Multidisciplinary
Zhaomin Peng, Dehai Zhang, Shuqi Ge, Jin Meng
Summary: In this study, a finite element model (FEM) is proposed to quantify the near-field interactions, and to investigate the edge effect and antenna effect in THz s-SNOM. Our results indicate that the proposed model can give us a better understanding of the near-field interactions and direct the parameter design of the probe for THz s-SNOM.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Physical
Yeongkon Jeong, Sang-Hun Lee, Soo Jong Park, Yeeun Roh, Byunghyuck Moon, Geon Lee, Shin Woo Kang, Byeong-Kwon Ju, Minah Seo, Young Min John
Summary: This report introduces the use of terahertz spectroscopy for monitoring the photo-degradation of organic materials. The measured THz transmittances can non-destructively present the aging process of the materials. Additionally, a sensing chip based on nano-metamaterial is introduced for highly sensitive detection of chemical conformational change on extremely thin surfaces.
APPLIED SURFACE SCIENCE
(2022)
Article
Engineering, Civil
Yasitha Warahena Liyanage, Daphney-Stavroula Zois, Charalampos Chelmis
Summary: This paper addresses the issue of detecting accidents on a freeway using speed sensors distributed spatially. A novel Bayesian quickest change detection formulation is introduced to address this issue, considering both the average detection delay and false alarm rate. Two methods for recursively estimating unknown parameters and four aggregation methods exploiting spatial correlations are proposed. Extensive evaluation results show significant improvements in average detection delay and false alarm rate compared to prior work.
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
(2022)
Article
Physics, Applied
Xiao Guo, Xin He, Zach Degnan, Bogdan C. Donose, Karl Bertling, Arkady Fedorov, Aleksandar D. Rakic, Peter Jacobson
Summary: Superconducting quantum circuits are a leading quantum computing platform, and it is crucial to identify and address material imperfections that lead to decoherence for practical advancements. The study used terahertz scanning near-field optical microscopy to probe the local properties of wet-etched aluminum resonators on silicon, revealing higher carrier concentration in silicon within the etched channel compared to buffer oxide etched silicon. The results demonstrate that near-field THz investigations can be used to quantitatively evaluate and identify inhomogeneities in quantum devices.
APPLIED PHYSICS LETTERS
(2021)
Article
Biochemical Research Methods
Jimin Wu, Vivek Boominathan, Ashok Veeraraghavan, Jacob T. Robinson
Summary: Traditional miniaturized fluorescence microscopes struggle to simultaneously achieve high spatial resolution and large field of view. Lensless microscopes offer a solution but lack real-time visualization due to slow image reconstruction. This paper presents a lensless microscope that achieves real-time image reconstruction using a neural network-based method. The reconstruction speed is increased by over 10000 times, enabling visualization at more than 25 frames per second with a resolution of better than 7 μm over a field of view of 10 mm². This real-time capability enhances user-friendly interaction with lensless microscopes.
BIOMEDICAL OPTICS EXPRESS
(2023)
Article
Optics
Feng Lan, Luyang Wang, Hongxin Zeng, Shixiong Liang, Tianyang Song, Wenxin Liu, Pinaki Mazumder, Ziqiang Yang, Yaxin Zhang, Daniel M. Mittleman
Summary: In this article, a reconfigurable metasurface based on GaN technology is introduced, which can enable agile engineering of THz wave fronts. The device can switch between a wide range of configurations, providing nearly arbitrary wave front control for signals near 0.34 THz. This technology has the potential to revolutionize sensing, imaging, and networking.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Acoustics
Lin Geng, Xing-Guo Chen, Shu-Ping He, Chun-Dong He
Summary: This paper proposes a sparse real-time near-field acoustic holography method for the precise and stable reconstruction of a transient sound field. By establishing a convolution equation and applying an optimization algorithm, the pressure time-wavenumber spectrum of the reconstruction plane is obtained. Numerical simulation results demonstrate the reconstruction capacity of the proposed method and its superiority compared to other methods.
JOURNAL OF SOUND AND VIBRATION
(2024)
Article
Chemistry, Multidisciplinary
Genwang Wang, Ye Ding, Haotian Long, Yanchao Guan, Xiwen Lu, Yang Wang, Lijun Yang
Summary: This paper reports on the simulations of electric and force fields at the tips of metallic probes irradiated by polarized laser output from a scanning near-field optical microscope probe. The results demonstrate that polarized laser can induce nanoscale evanescent fields with high intensity, which effectively move nanoparticles. The paper also discusses schemes with dual probes, showing that different combinations of metallic probes and polarized lasers provide diverse near-field and corresponding optical force.
APPLIED SCIENCES-BASEL
(2022)
Article
Physics, Applied
Xiao Guo, Karl Bertling, Aleksandar D. Rakic
Summary: Scattering-type scanning near-field optical microscopy (s-SNOM) allows for characterization of optical properties at nanoscale below the diffraction limit, with a new calibration method proposed for extracting optical constants without prior knowledge of probe geometry. The technique's accuracy is comparable to traditional far-field methods and provides spatial distribution of optical constants at nanoscale, making it applicable for s-SNOM measurements in other spectral ranges.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Yihang Fan, Xiaotian Xue, Fei Yang, Jianqiao Zhao, Xiaoyu Xiong, Jingbo Sun, Weipeng Wang, Ji Shi, Ji Zhou, Zhengjun Zhang
Summary: The plasmonic properties of nano materials/structures have been extensively studied using SNOM, but the quantification of SNOM measurements has remained a challenge. In this study, researchers used a point-dipole model and theoretical calculations to establish the quantitative relationship between measured results and actual near-field electric field strength. They were able to experimentally reconstruct the near-field electric field using this relationship, and also developed an experimental technique and FEM simulation for acquiring the relationship and reconstructing the field.
Article
Nanoscience & Nanotechnology
Yuezhen Lu, Lucy L. L. Hale, Abdullah M. M. Zaman, Sadhvikas J. J. Addamane, Igal Brener, Oleg Mitrofanov, Riccardo Degl'Innocenti
Summary: Metamaterial resonators in the terahertz frequency range have proved to be efficient and versatile platforms with applications in integrated optical devices and fundamental research. However, characterizing the modes supported by these subwavelength elements has been challenging, relying on indirect observation of collective far-field transmission/reflection properties of arrays. In this study, we present a broadband time-domain spectroscopic investigation of individual metamaterial resonators using a THz aperture scanning near-field microscope (a-SNOM). The results allow mapping and quantitative analysis of confined modes supported by the resonators, including weakly radiative modes.
Article
Nanoscience & Nanotechnology
Ryota Aoki, Kento Uchida, Koichiro Tanaka
Summary: This study investigates a method of inducing topological phase transitions through polarization-controlled infrared excitation and experimentally studies the phenomenon in Td-WTe2 thin films. The experimental results show that polarization-selective excitation leads to the rapid loss of carrier distribution, making it difficult to control the photo-induced phase transition.
Article
Environmental Sciences
Mostafa Saidur Rahim Khan, Pattaphol Yuktadatta, Yoshihiko Kadoya
Summary: The COVID-19 pandemic has different impacts on the social and economic aspects of people's lives, leading to varying levels of loneliness. This study investigates the extent of loneliness among men and women of different ages in Japan during the pandemic and explores the underlying causes. The findings show that loneliness is prevalent among the Japanese population, and a significant number of individuals experienced loneliness for the first time during the pandemic. Loneliness is generally more pronounced among younger respondents, while older people became lonelier during the pandemic. Significant differences in loneliness were observed across age and gender subgroups. While depression and subjective health status contribute to loneliness, there is no single explanation for pandemic-induced loneliness, with the causes varying among different groups. However, it was found that older people are at a higher risk of developing loneliness during the pandemic due to various socioeconomic and behavioral factors. The study suggests that health authorities should not generalize cases of loneliness but provide individual interventions tailored to each group to prevent further complications.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2022)
Article
Green & Sustainable Science & Technology
Pattaphol Yuktadatta, Shunsuke Ono, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: The COVID-19 pandemic has caused a recession globally, leading to financial difficulties for many households. To mitigate these effects, the Japanese government provided a one-time cash payment to registered residents at the beginning of the pandemic. However, only 20% of recipients expressed satisfaction with this policy. Factors such as gender, age, education level, and anxiety about the future influenced satisfaction levels, while marriage, occupation, household assets, and subjective health positively affected satisfaction. The study highlights the importance of considering the diverse challenges faced by different socioeconomic groups when designing future policies.
Article
Business
Yoshihiko Kadoya, Naheed Rabbani, Mostafa Saidur Rahim Khan
Summary: Despite its importance in risk management, insurance literacy among older people has been largely overlooked in academic research. Our study using data from a survey on the economic status of the Japanese elderly revealed a low level of insurance literacy among older people in Japan, especially the oldest subgroup and women. Regression results indicated that insurance literacy was more likely among men, married individuals, younger individuals, those with moderate education, higher financial assets, and work experience in management, business, or finance. These findings highlight the importance of social learning in insurance literacy.
JOURNAL OF CONSUMER AFFAIRS
(2022)
Article
Multidisciplinary Sciences
Tomoki Hiraoka, Yuta Inose, Takashi Arikawa, Hiroshi Ito, Koichiro Tanaka
Summary: This paper introduces a resonant-tunneling-diode terahertz oscillator that achieves passive mode-locking and frequency-comb generation through optical feedback. The oscillator, based on a semiconductor device, covers the frequency range of 0.1 to 2 THz. With external bias modulation, the spacing between the comb lines is significantly reduced. A simulation model successfully reproduces the mode-locking behavior. This oscillator can serve as a future frequency standard for terahertz sensing and wireless communications.
NATURE COMMUNICATIONS
(2022)
Article
Environmental Sciences
Mostafa Saidur Rahim Khan, Trinh Xuan Thi Nguyen, Sumeet Lal, Somtip Watanapongvanich, Yoshihiko Kadoya
Summary: The hesitancy of Japanese youth towards the COVID-19 vaccine has been widely discussed, but there is a lack of comprehensive studies on the apprehension towards the booster dose and its causes. A survey conducted by Hiroshima University revealed that a significant proportion of the Japanese population, especially younger men, are hesitant to receive the booster dose. The study found that there is a difference in booster dose aversion between age groups, and subjective health status and future anxiety are associated with vaccine hesitancy among men and women of different ages.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2022)
Article
Optics
F. Blanchard, J. E. Nkeck, L. Guiramand, S. Zibod, K. Dolgaleva, T. Arikawa, K. Tanaka
Summary: This study demonstrates the ability of the surfaces of SrTiO3 crystals at room temperature to act as ultrafast sensors, enabling sub-picosecond switching through the Kerr effect and recording polar THz intensity with spatial resolution below the diffraction limit through THz-field-induced dipole alignment followed by multi-picosecond relaxation time recovery. The contrast sensitivity and spatial resolution achieved by the STO sensor are significantly superior to those of present-day near-field THz sensors based on the linear Pockels effect, providing a new strategy for building an ultrafast space-time THz memory.
Article
Green & Sustainable Science & Technology
Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: The COVID-19 pandemic has provided an opportunity for fraudsters to swindle money through necessary goods and services, but there is a lack of comparative studies on financial frauds before and during the pandemic. This study examines financial frauds using panel survey data before and during the pandemic, and finds no significant change in frauds at the aggregate level, but identifies changes in specific fraud types. Regression analysis reveals various risk factors associated with being victims of financial frauds during the pandemic. The study emphasizes the importance of considering these differences in combating financial frauds.
Article
Multidisciplinary Sciences
Zhenya Zhang, Fumiya Sekiguchi, Takahiro Moriyama, Shunsuke C. Furuya, Masahiro Sato, Takuya Satoh, Yu Mukai, Koichiro Tanaka, Takafumi Yamamoto, Hiroshi Kageyama, Yoshihiko Kanemitsu, Hideki Hirori
Summary: The authors studied HoFeO3 crystal using multicycle THz magnetic pulses enhanced strongly by spiral-shaped microstructure. The observed Faraday ellipticity demonstrates second- and third-order harmonics of the magnetization oscillation and an asymmetric oscillation behavior. The ability to drive a spin system to state far from the equilibrium is indispensable for investigating spin structures of antiferromagnets and their functional nonlinearities for spintronics.
NATURE COMMUNICATIONS
(2023)
Article
Green & Sustainable Science & Technology
Abdul-Salam Sulemana, Sumeet Lal, Trinh Xuan Thi Nguyen, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: Pandemic fatigue has led to a decline in government-mandated preventive measures to contain COVID-19. The first study of its kind in Japan examined the socioeconomic factors contributing to this decline. The study found decreases in hand hygiene, mask-wearing, and social distancing, with men and financially satisfied individuals showing less compliance. Selective prevention programs targeting specific groups are important for effective pandemic management and reducing fatigue or discontentment.
Article
Green & Sustainable Science & Technology
Sumeet Lal, Trinh Xuan Thi Nguyen, Abdul-Salam Sulemana, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: Whether non-compliance with hand sanitization is related to impatience or impulsivity is still uncertain. This study examines the influence of time discounting on hand-sanitizing behavior in Japan and finds that deviation from hand sanitization is seen as an impulsive decision, especially among females. However, there is no notable impact of impatience on hand sanitization. The study highlights the importance of considering gender differences in designing health-promoting measures.
Article
Psychology, Multidisciplinary
Yu Kuramoto, Honoka Nabeshima, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: Similar to Japan, China faces challenges in providing long-term care for the elderly due to changes in demographics and socioeconomic factors. This study investigates the impact of socioeconomic factors on the perception of family caregiving norms in China, using a comparative household dataset. The results show that rural residency, household assets, and government dependency are positively associated with the perception of care. Interestingly, rural residents in China have a more positive perception of family caregiving norms compared to Japan, but women in rural areas perceive caregiving negatively.
BEHAVIORAL SCIENCES
(2023)
Article
Psychology, Multidisciplinary
Sayaka Fukuda, Takuya Katauke, Saki Hattori, Soma Tanaka, Yu Kurushima, Yoichi Arakawa, Nao Ikeda, Haruka Kinoshita, Mikito Urayama, Ryota Shimizu, Tomohide Anan, Shinya Ifuku, Yuta Shiwaku, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: Despite the efforts by the Japanese government to reduce alcohol consumption, there is still a need for improvement. This study explores the relationship between impulsivity and drinking behavior and finds that procrastination, a proxy measure of impulsivity, is significantly associated with drinking behavior. The findings suggest that impulsive individuals may discount their future health, highlighting the importance of considering impulsivity in policymaking.
BEHAVIORAL SCIENCES
(2023)
Article
Green & Sustainable Science & Technology
Abdul-Salam Sulemana, Trinh Xuan Thi Nguyen, Sumeet Lal, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: Although studies on loneliness during the COVID-19 pandemic in rural and urban areas have yielded inconsistent results, our nationwide study utilizing longitudinal data from Hiroshima University's Household Behavior and Finance Survey sheds light on the impact of urban-rural differences on loneliness. Our results show that approximately 50% of the surveyed individuals experienced long-term loneliness, while about 6.5% developed loneliness during the pandemic. Socioeconomic changes such as living alone, leaving full-time employment, and decreased financial satisfaction were identified as high-risk factors for loneliness, with their effects varying between rural and urban areas.
Article
Green & Sustainable Science & Technology
Takuya Katauke, Sayaka Fukuda, Mostafa Saidur Rahim Khan, Yoshihiko Kadoya
Summary: The existing literature suggests that financial literacy can be used as a measure of rational decision making. This study investigates whether financial literacy reduces impulsivity in financial and economic decisions. The results show that financial literacy is negatively associated with impulsive decision making, especially among respondents aged over 40 and among female respondents. The findings imply that financial literacy could be used as an alternative policy intervention to change impulsivity preferences.
