• Title/Summary/Keyword: frequency-response

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Photo-Transistors Based on Bulk-Heterojunction Organic Semiconductors for Underwater Visible-Light Communications (가시광 수중 무선통신을 위한 이종접합 유기물 반도체 기반 고감도 포토트랜지스터 연구)

  • Jeong-Min Lee;Sung Yong Seo;Young Soo Lim;Kang-Jun Baeg
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.2
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    • pp.143-150
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    • 2023
  • Underwater wireless communication is a challenging issue for realizing the smart aqua-farm and various marine activities for exploring the ocean and environmental monitoring. In comparison to acoustic and radio frequency technologies, the visible light communication is the most promising method to transmit data with a higher speed in complex underwater environments. To send data at a speedier rate, high-performance photodetectors are essentially required to receive blue and/or cyan-blue light that are transmitted from the light sources in a light-fidelity (Li-Fi) system. Here, we fabricated high-performance organic phototransistors (OPTs) based on P-type donor polymer (PTO2) and N-type acceptor small molecule (IT-4F) blend semiconductors. Bulk-heterojunction (BHJ) PTO2:IT-4F photo-active layer has a broad absorption spectrum in the range of 450~550 nm wavelength. Solution-processed OPTs showed a high photo-responsivity >1,000 mA/W, a large photo-sensitivity >103, a fast response time, and reproducible light-On/Off switching characteristics even under a weak incident light. BHJ organic semiconductors absorbed photons and generated excitons, and efficiently dissociated to electron and hole carriers at the donor-acceptor interface. Printed and flexible OPTs can be widely used as Li-Fi receivers and image sensors for underwater communication and underwater internet of things (UIoTs).

Ubiquitin E3 ligases in cancer: somatic mutation and amplification

  • Eun-Hye Jo;Mi-Yeon Kim;Hyung-Ju Lee;Hee-Sae Park
    • BMB Reports
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    • v.56 no.5
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    • pp.265-274
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    • 2023
  • Defects in DNA double-strand break (DSB) repair signaling permit cancer cells to accumulate genomic alterations that confer their aggressive phenotype. Nevertheless, tumors depend on residual DNA repair abilities to survive the DNA damage induced by genotoxic stress. This is why only isolated DNA repair signaling is inactivated in cancer cells. DNA DSB repair signaling contributes to general mechanism for various types of lesions in diverse cell cycle phases. DNA DSB repair genes are frequently mutated and amplified in cancer; however, limited data exist regarding the overall genomic prospect and functional result of these modifications. We list the DNA repair genes and related E3 ligases. Mutation and expression frequencies of these genes were analyzed in COSMIC and TCGA. The 11 genes with a high frequency of mutation differed between cancers, and mutations in many DNA DSB repair E3 ligase genes were related to a higher total mutation burden. DNA DSB repair E3 ligase genes are involved in tumor suppressive or oncogenic functions, such as RNF168 and FBXW7, by assisting the functionality of these genomic alterations. DNA damage response-related E3 ligases, such as RNF168, FBXW7, and HERC2, were generated with more than 10% mutation in several cancer cells. This study provides a broad list of candidate genes as potential biomarkers for genomic instability and novel therapeutic targets in cancer. As a DSB related proteins considerably appear the possibilities for targeting DNA repair defective tumors or hyperactive DNA repair tumors. Based on recent research, we describe the relationship between unstable DSB repairs and DSB-related E3 ligases.

Movable Anchorage System for Mitigation of Cable Vibration in Cable-Stayed Bridges with Sag (Sag가 고려된 사장교 케이블의 진동저감을 위한 Movable Anchorage 시스템)

  • Hwang, Inho;Park, Jun Hyung;Lee, Jong Seh
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5A
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    • pp.657-664
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    • 2008
  • Rain-wind induced cable vibration can cause the damages in the cable-stayed bridge due to very little inherent damping characteristics and low fundamental frequency. External Dampers attached to stay cables near anchorages have been shown to be effective means at short stay-cables. However, installation locations of external dampers are limited to a particular range due to aesthetic and practical reasons for very long stay-cables. A recent study by the authors showed that the stay-cable vibration system can perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges. This paper extends the previous study on the taut string representation of the cable by adding cable sag and inclination. The response of the proposed system compared to those of the cable with and without an external damper, and the movable anchorage system provides very effective mitigation of cable vibration. Cable damping ratio is seen to be remarkably reduced by movable anchorage system for a wide range of cable sag. This result shows that the sag effects of the proposed system should be considered.

Porosity-dependent vibration investigation of functionally graded carbon nanotube-reinforced composite beam

  • Abdulmajeed M. Alsubaie;Ibrahim Alfaqih;Mohammed A. Al-Osta;Abdelouahed Tounsi;Abdelbaki Chikh;Ismail M. Mudhaffar;Saeed Tahir
    • Computers and Concrete
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    • v.32 no.1
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    • pp.75-85
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    • 2023
  • This work utilizes simplified higher-order shear deformation beam theory (HSDBT) to investigate the vibration response for functionally graded carbon nanotube-reinforced composite (CNTRC) beam. Novel to this work, single-walled carbon nanotubes (SWCNTs) are distributed and aligned in a matrix of polymer throughout the beam, resting on a viscoelastic foundation. Four un-similar patterns of reinforcement distribution functions are investigated for the CNTRC beam. Porosity is another consideration taken into account due to its significant effect on functionally graded materials (FGMs) properties. Three types of uneven porosity distributions are studied in this study. The damping coefficient and Winkler's and Pasternak's parameters are considered in investigating the viscosity effect on the foundation. Moreover, the impact of different parameters on the vibration of the CNTRC beam supported by a viscoelastic foundation is discussed. A comparison to other works is made to validate numerical results in addition to analytical discussions. The findings indicate that incorporating a damping coefficient can improve the vibration performance, especially when the spring constant factors are raised. Additionally, it has been noted that the fundamental frequency of a beam increases as the porosity coefficient increases, indicating that porosity may have a significant impact on the vibrational characteristics of beams.

A Study on the Perception of Asan Hot Springs Utilization Post-Corona Pandemic (코로나 팬데믹 이후의 아산 온천 이용 선호도에 관한 연구)

  • Jong-Min Woo
    • Journal of The Korean Society of Integrative Medicine
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    • v.11 no.4
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    • pp.189-198
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    • 2023
  • Purpose: This study aims to investigate the preferences of hot spring users regarding the utilization of Asan's hot springs after the COVID-19 pandemic. Methods: A survey was conducted on 340 hot spring users visiting hot spring resorts in the Onyang, Dogo, and Asan hot spring districts. The survey was conducted twice from November 5th to November 7th, 2021, and from May 25th to 26th, 2022. The survey included general questions, such as the frequency of hot spring usage, the purpose of visits, and the intention for future visits. Specific questions were related to Asan hot springs, focusing on the reasons for choosing Asan, its perceived advantages, and improvement suggestions. Results: The survey revealed that the average number of visits to hot springs was less than five in the past five years, and the main reason for visiting was to recover from fatigue. A percentage of respondents said they would use hot springs more often when the COVID-19 pandemic ends. When asked about their reasons for visiting Asan hot springs, responses varied by age. However, across all groups, the majority considered "good water" as an advantage of Asan hot springs, while improvements to "hot spring facilities" was the highest response among all age groups. Thus, despite the decline in the number of customers due to COVID-19, the overall perception of hot springs remains positive. This suggests a promising future for the hot spring industry, with the potential for a return to pre-pandemic usage levels. Conclusion: These results provide valuable foundational data for informing policy development aimed at revitalizing the hot spring industry in the post-COVID-19 era.

A Study on the Response of Military Sexual Violence: Based on Big Data Analysis of Related Articles (군 성폭력 대응 실태연구: 관련 기사 빅 데이터 분석 중심)

  • Young-Ran Kim;Min-Sun Lee;Hyun Song
    • Industry Promotion Research
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    • v.8 no.4
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    • pp.131-137
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    • 2023
  • This study collected and analyzed articles related to military sex crimes covered in the news from February 2019 to May 28, 2022 in order to identify problems arising from sexual crimes in the military. In order to understand the current status of military sexual violence reported in the media, articles were collected using BIGKinds, a news big data analysis system, and using the Textom program, the study was conducted using frequency analysis by period, word cloud, and semantic network analysis techniques for keywords. The study was conducted using the technique. As a result of data analysis, first, it was confirmed that the public's attention was focused on the victims in reports related to sex crimes within the military. Second, the problem of the lukewarm system of the relevant authorities in responding to sex crimes was revealed. Third, there was a lack of support for victims of sex crimes.

Microalgal diversity in response to differential heavy metals-contaminated wastewater levels at North Nile Delta, Egypt

  • Maha Youssef Kamal Elmousel;Eithar El-Mohsnawy;Yassin Mohamed Al-Sodany;Eladl Galal Eltanahy;Mohamed Ali Abbas;Awatif Saad Ali
    • Journal of Ecology and Environment
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    • v.47 no.3
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    • pp.157-167
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    • 2023
  • Background: The most hazardous wastewater sources in the northern part of the Middle Nile Delta, Egypt; receiving a massive amount of agricultural, industrial, and sewage drainage are Kitchener drain which is one of the tallest drainage systems, and Burullus Lake which represents the 2nd largest Egyptian coastal lake. Results: The current work is to determine the abundance and frequency of cyanophytes, chlorophytes, and bacillariophytes and the correlation between them and environmental abiotic components. Among sixty nine microalgal species, 19 species are belong Cyanophyta, 26 belong Chlorophyta and 24 belong Bacillariophyta. Genus Scenedesmus (Chlorophyta) was the most abundant in the study area (13 species), followed by Genus Oscillatoria (9 species) and Genus Navicula (7 species). Nostoc muscorum and Chlorella vulgaris were the most common and recorded in all sites (100% of the locations) under study. The application of the two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis revealed agglomerating of 4 groups (communities) at 4th level of classification and reasonable segregation between these groups. Zinc, cadmium and lead were showed the highest levels (0.26±0.03, 0.26±0.06, and 0.17±0.01 ppm, respectively). Conclusions: The correlation analysis between water and community variables indicated a high negative correlation of total algae richness with nickel (r = -0.936, p < 0.01). Cyanophyta and Bacillariophyta were correlated negatively (r = -0.842, p < 0.01). However, Chlorophyta showed a negative richness with each of Ni and Pb (r = -0.965, -0.873, respectively) on one hand and a high positive correlation was revealed (r = 0.964) with all environmental variables on the other hand.

A Study on the Operating Characteristics of the Aged ELCB according to the Overcurrent (노후화된 누전차단기의 과전류 동작 특성에 관한 연구)

  • Ye Jin Park;Sin Dong Kang;Jae-Ho Kim
    • Journal of the Korean Society of Safety
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    • v.38 no.5
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    • pp.1-7
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    • 2023
  • This study analyzes the operational characteristics of 311 aged and non-aged residual current circuit breakers (RCCBs) in low-voltage consumer contexts. It investigates the influence of external temperature and harmonics based on the rated current multiples. To simulate temperature variations, a convectional oven was used around the circuit breakers. Additionally, the generation of harmonic reference signals and data measurement for overcurrent experiments were conducted using NI SCXI, myDAQ, and LabVIEW. An observation revealed that as the ambient temperature increased, the operating time of RCCBs decreased in the time delay region. This was attributed to the faster response or bending of the bimetal, which is the tripping element. However, aged RCCBs encountered challenges with tripping outside the protective curve. The operating time of the circuit breakers exhibited an acceleration influenced by the order and content of harmonic currents, potentially leading to malfunctions. Aged RCCBs demonstrated faster operating times than their non-aged counterparts. However, the difference in operating time varied based on the manufacturer's and operating environment of the RCCBs. Frequent malfunctions of RCCBs can result in power outages. In cases where these circuit breakers fail to operate, they can lead to secondary damages, including electrical fires and shocks. Consequently, it is imperative to consider the operating environment of RCCBs and provide appropriate replacement cycles to mitigate these risks.

Single-Dose Toxicity Study of Intramuscular Neuralgia-Pharmacopuncture Injection in Rats

  • Ji Hye Hwang
    • Journal of Pharmacopuncture
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    • v.26 no.4
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    • pp.348-356
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    • 2023
  • Objectives: Neuralgia-pharmacopuncture (NP) was recently developed as a water-soluble type of pharmacopuncture inspired by CS (care special pain)-pharmacopuncture. I aimed to evaluate the toxic response and approximate lethal dose of when NP when administered intramuscularly to Sprague Dawley rats. Methods: The experimental group was divided into the NP test substance group and the saline control group and administered at a dose of 1.0 mL/animal to the posterior thigh muscles on both sides using a 1 mL syringe; each group consisted of five males and five females. Each rat was monitored for clinical signs and changes in body weight for 14 days after a single intramuscular injection. After completing observation, necropsy findings and localized tolerance at the injection site were assessed via gross necropsy and histopathological examination. Results: No deaths occurred in the NP or control group, regardless of sex. During the observation period, no changes (such as general symptoms, weight change, or visual observation results at the time of autopsy) were judged to be due to the test substance. Histopathological examination showed no changes at the administration site judged to be caused by the test substance in either the male or female test substance administration groups. In addition, mononuclear cell infiltration of the outer membrane of the femoris muscle at the administration site was observed at the same frequency and extent in the control and NP groups, and was judged to be caused by physical stimulation by the injection needle; therefore, it had no toxicological significance. Conclusion: Based on the above results, the approximate lethal dose for a single intramuscular administration of the test substance NP in Sprague-Dawley rats was judged to be > 1.0 mL/animal, and there were no findings that were judged to be due to the test substance at the administration site.

A Framework for Quantifying the Damage to Residential Facilities Caused by Typhoon Changes (태풍 변화로 인한 주거시설 피해 정량화 프레임 워크 제안)

  • Kim, Ji-Myong;Son, Seunghyun
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.6
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    • pp.797-807
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    • 2023
  • This research aims to investigate the alterations in typhoon patterns attributable to climate change and to quantitatively assess the risk of damage to residential structures. The increasing prevalence of climate anomalies and severe weather events, a consequence of global warming, is causing escalating damage globally. Notably, numerous countries are facing substantial devastation due to shifts in typhoon trajectories. Despite this, there exists a gap in empirical research quantifying the impact of these changes on building integrity and the associated risk alterations driven by climate change. In addressing this gap, our study analyzes the frequency and intensity of typhoons impacting Korea, examining the evolution of these meteorological phenomena. Furthermore, we employ the Korean Typhoon Vulnerability Function for residential facilities to quantify the altered risk posed by these changing patterns. The outcomes of this study provide the private sector with essential data to formulate diverse scenarios and business strategies in response to the escalating risks of typhoon-related damage. Additionally, it equips governmental bodies with the necessary insights to develop comprehensive risk management strategies to mitigate the effects of future typhoons.