Enhanced terahertz conductivity in ultra-thin gold film deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS)-coated Si substrates

Various material properties change considerably when material is thinned down to nanometer thicknesses. Accordingly, researchers have been trying to obtain homogeneous thin films with nanometer thickness but depositing homogeneous few nanometers thick gold film is challenging as it tends to form islands rather than homogenous film. Recently, studies have revealed that treating the substrate with an organic buffer, (3-mercaptopropyl) trimethoxysilane (MPTMS) enables deposition of ultra-thin gold film having thickness as low as 5 nm. Different aspects of MPTMS treatment for ultrathin gold films like its effect on the structure and optical properties at visible wavelengths have been investigated. However, the effect of the MPTMS treatment on electrical conductivity of ultra-thin gold film at terahertz frequency remains unexplored. Here, we measure the complex conductivity of nanometer-thick gold films deposited onto an MPTMS-coated silicon substrate using terahertz time-domain spectroscopy. Following the MPTMS treatment of the substrate, the conductivity of the films was found to increase compared to those deposited onto uncoated substrate for gold films having the thickness less than 11 nm. We observed 5-fold enhancement in the conductivity for a 7 nm-thick gold film. We also demonstrate the fabrication of nanoslot-antenna arrays in 8.2-nm-thick gold films. The nanoslot-antenna with MPTMS coating has resonance at around 0.5 THz with an electric field enhancement of 44, whereas the nanoslot-antenna without MPTMS coating does not show resonant properties. Our results demonstrate that gold films deposited onto MPTMS-coated silicon substrates are promising advanced materials for fabricating ultra-thin terahertz plasmonic devices

Constraint-based Latent Profile Analysis to Investigate the Physical Activity Market Segments among Chinese College Students

A segmentation study is conducted via constraint-based latent profile analysis (based on the hierarchical model of leisure constraint), focusing on Chinese college students. Multi-profile analysis further compares key determinants (i.e., constraints/motives) of physical activity intention by profile. Three profiles emerged: ‘body image-conscious physically active’, ‘noncommittal but achievement-driven’, and ‘constrained but motivated by enjoyment/socialization’. Each profile reports distinctive patterns in perceived levels of constraints, motives, and intention. Constraints/motives identified as determinants for intention vary by profile. Compared to North America, China tends to have more college students seeing physical activity as a task than leisure. Profile-specific marketing strategies are suggested

I Want To vs. I Can\u27t: A Case Study On Motives And Constraints For Chinese College Students Attending Or Media Viewing The 2018 Winter Olympics

This case study aims to understand what motives and constraints affect Chinese college student’s intention to attend or media view the 2018 Winter Olympics. Grounded on ‘negotiation of motives and constraints’, key internal and external motives and intrapersonal, interpersonal, and structural constraints were identified through thought-listing procedures (n=35); their influences on attendance and media viewing intentions were tested based on online surveys (n=313) and structural equation modeling. Highlighting key findings, motives of social influence and interest in winter sport had strong effects on both intentions. Structural constraints such as lack of time were more likely to affect both intentions than intra- and inter-personal constraints. Interestingly, lack of knowledge was anticipated to be a constraint but was found positively associated with media viewing intention. Based on the findings, strategies to stimulate Olympics consumption are proposed, which can be informative for the preparation of the 2022 Beijing Winter Olympics and sport organizations targeting Chinese college student consumers

Navigating AI transitions: how coaching leadership buffers against job stress and protects employee physical health

The dynamic interplay between Artificial Intelligence (AI) adoption in modern organizations and its implications for employee well-being presents a paramount area of academic exploration. Within the context of rapid technological advancements, AI’s promise to revolutionize operational efficiency juxtaposes challenges relating to job stress and employee health. This study explores the nuanced effects of Artificial Intelligence (AI) adoption on employee physical health within organizational settings, investigating the potential mediating role of job stress and the moderating influence of coaching leadership. Drawing from the conservation of resource theory, the research hypothesized that AI adoption would negatively impact employee physical health both directly and indirectly through increased job stress. Critically, our conceptual model underscores the mediating role of job stress between AI adoption and physical health. Further, introducing a novel dimension to this discourse, we postulate the moderating influence of coaching leadership. To empirically test the hypotheses, we gathered survey data from 375 South Korean workers with a three-wave time-lagged research design. Our results demonstrated that all the hypotheses were supported. The results have significant implications for organizational strategies concerning AI implementation and leadership development

Near-maximum microwave absorption in a thin metal film at the pseudo-free-standing limit

Electromagnetic absorbers based on ultra-thin metallic film are desirable for many applications such as plasmonics, metamaterials, and long-wavelength detectors. A metallic film will achieve a maximum 50% of electromagnetic wave absorption, frequency independent, at a thickness defined by its conductivity, typically in the sub-Angstrom range for good metals if bulk conductivity is maintained throughout. This makes it extremely difficult to obtain substantial absorption from thin metal films, in contrast to 2D materials such as graphene. Luckily, however, from a practical point of view, metal conductivity is drastically reduced as the film becomes sub-100 nm, to make it a race between the thinnest possible metal thickness experimentally achievable vs the conductivity reduction. Here, we demonstrate a near-50% absorption at a gold film thickness of 6.5 nm, with conductivity much reduced from the bulk value, down to the range of 10(6) Siemens per meter. Studying the effect of the substrate thickness, we found that the common cover glass, with its thickness much smaller than the wavelength, achieves symmetric absorption of 44%, implying that a pseudo-free-standing limit is achieved. Our work may find applications in infrared sensing as in bolometers and biomedical sensing using microwaves

Broadband high-performance terahertz polarizer based on a dense array of 5 nm gap slit antennas

Critical factors for terahertz polarizers include broadband operation, high transmittance, and a good extinction ratio. In this paper, using a 5 nm-wide metallic slit array with a 200 nm periodicity as a wire grid polarizer, we achieved over 95% transmittance with an average extinction ratio of 40 dB, over the entire spectrum as defined by the terahertz time-domain spectroscopy (0.4 - 2 THz). Theoretical calculations revealed that the slit array can show 100% transmission up to 5 THz, and wider bandwidths with a higher cutoff frequency can be achieved by reducing the slit periodicity. These results provide a novel approach for achieving a broadband THz polarizer and open a new path for seamless integration of the polarizers with nanophotonic applications. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreemen

Ultra-Narrow Metallic Nano-Trenches Realized by Wet Etching and Critical Point Drying

A metallic nano-trench is a unique optical structure capable of ultrasensitive detection of molecules, active modulation as well as potential electrochemical applications. Recently, wet-etching the dielectrics of metal-insulator-metal structures has emerged as a reliable method of creating optically active metallic nano-trenches with a gap width of 10 nm or less, opening a new venue for studying the dynamics of nanoconfined molecules. Yet, the high surface tension of water in the process of drying leaves the nano-trenches vulnerable to collapsing, limiting the achievable width to no less than 5 nm. In this work, we overcome the technical limit and realize metallic nano-trenches with widths as small as 1.5 nm. The critical point drying technique significantly alleviates the stress applied to the gap in the drying process, keeping the ultra-narrow gap from collapsing. Terahertz spectroscopy of the trenches clearly reveals the signature of successful wet etching of the dielectrics without apparent damage to the gap. We expect that our work will enable various optical and electrochemical studies at a few-molecules-thick level

The pioneer round of translation ensures proper targeting of ER and mitochondrial proteins

The pioneer (or first) round of translation of newly synthesized mRNAs is largely mediated by a nuclear cap-binding complex (CBC). In a transcriptome-wide analysis of polysome-associated and CBC-bound transcripts, we identify RN7SL1, a noncoding RNA component of a signal recognition particle (SRP), as an interaction partner of the CBC. The direct CBC???SRP interaction safeguards against abnormal expression of polypeptides from a ribosome???nascent chain complex (RNC)???SRP complex until the latter is properly delivered to the endoplasmic reticulum. Failure of this surveillance causes abnormal expression of misfolded proteins at inappropriate intracellular locations, leading to a cytosolic stress response. This surveillance pathway also blocks protein synthesis through RNC???SRP misassembled on an mRNA encoding a mitochondrial protein. Thus, our results reveal a surveillance pathway in which pioneer translation ensures proper targeting of endoplasmic reticulum and mitochondrial proteins

HyperCLOVA X Technical Report

We introduce HyperCLOVA X, a family of large language models (LLMs) tailored to the Korean language and culture, along with competitive capabilities in English, math, and coding. HyperCLOVA X was trained on a balanced mix of Korean, English, and code data, followed by instruction-tuning with high-quality human-annotated datasets while abiding by strict safety guidelines reflecting our commitment to responsible AI. The model is evaluated across various benchmarks, including comprehensive reasoning, knowledge, commonsense, factuality, coding, math, chatting, instruction-following, and harmlessness, in both Korean and English. HyperCLOVA X exhibits strong reasoning capabilities in Korean backed by a deep understanding of the language and cultural nuances. Further analysis of the inherent bilingual nature and its extension to multilingualism highlights the model's cross-lingual proficiency and strong generalization ability to untargeted languages, including machine translation between several language pairs and cross-lingual inference tasks. We believe that HyperCLOVA X can provide helpful guidance for regions or countries in developing their sovereign LLMs.Comment: 44 pages; updated authors list and fixed author name