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Air-stable,all-dry transferred ReS_(2)/GaSe heterostructure-based NO_(2)gas sensor

Journal of Materials Science & Technology 2024年第1期168卷 79-87页

作者： A.Venkatesan Hyeyoon Ryu Anupom Devnath Hyungyu yoo Seunghyun Lee Department of Electronic Engineering Kyung Hee UniversityYongin-Si 17104South Korea Department of Electronics and Information Convergence Engineering Kyung Hee UniversityYongin-Si 17104South Korea

Two-dimensional(2D)materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ***,the poor response time and incomplete recovery re-strict their application in practical,high performance gas *** this work,we fabricated air-stable ReS_(2)/GaSe heterostructure-based NO_(2)gas sensors with excellent gas sensing response,recovery,selectiv-ity and a low limit of detection(LOD)toward nitrogen dioxide(NO_(2)).The ReS_(2)/GaSe heterostructure was prepared via mechanical exfoliation and an all-dry transfer *** the sensing measurements,temperature-dependant transport measurements were carried *** Schottky Barrier Height(SBH)of the ReS_(2)/GaSe heterostructure was calculated and the corresponding transport mechanisms were *** fabricated gas sensors showed a significant response enhancement with full reversibility to-ward ppm-level NO_(2)(response of∼17%at 3 ppm,a LOD of∼556 ppb)at an operating temperature of(33°C).In particular,the total response and recovery time of the ReS_(2)/GaSe was revealed to be less than 4 min(∼38 s and∼174 s,respectively)for the 250 ppm concentration,which is one of the best response and recovery time toward ppm-level NO_(2).The excellent sensing performances and recovery characteris-tics of the ReS_(2)/GaSe structure are attributed to its efficient charge separation,unique interlayer coupling and desirable band *** atomically thin,ultrasensitive gas sensor that operates at room tem-perature is a strong technological contender to conventional metal oxide gas sensors,which often require elevated temperatures.

关键词： 2D materials All-dry transfer Gas sensor Van der Waals heterostructure ReS_(2)/GaSe Gas sensing response Transition metal dichalcogenide

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Oxidative coupling of methane over LaAlO3 perovskite catalysts prepared by a co-precipitation method: Effect of co-precipitation pH value

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Journal of Energy Chemistry 2019年第8期28卷 1-8,I0001页

作者： Yujin Sim Jihoon yoo Jeong-Myeong Ha Ji Chul Jung Department of Chemical Engineering Myongji UniversityYongin 17058 Republic of Korea Clean Energy Research Center Korea Institute of Science and TechnologySeoul 02792 Republic of Korea

Oxidative coupling of methane(OCM) was conducted over LaAlO3X catalysts that were prepared by a coprecipitation method using different co-precipitation pH values(X = 6–10). The aim is to investigate the effect of p H values on the catalytic activity of La AlO3 catalysts in this reaction. The results showed that the co-precipitation pH value affected greatly on the formation of chemical species of precipitate precursors in the co-precipitation step, leading to different phases of the finally obtained LaAlO3 *** the co-precipitation pH value increased up to 8, the lanthanum-related phases such as La2 O3 and La(OH)3 were gradually formed as by-products, preventing the formation of LaAlO3 perovskite crystalline structure and facilitating the formation of oxygen vacancies on catalyst surface. However, at pH value of9 or higher, the lanthanum content in the precipitate precursor was increased greatly. Not LaAlO3 perovskite but lanthanum-related phases were developed as main phases, reducing their catalytic activities in this reaction. Among LaAlO3 catalysts, the one prepared at pH = 8 showed the highest C2 yield due to its well-developed oxygen vacancies and electrophilic lattice oxygen. Therefore, the co-precipitation pH value strongly affected the LaAlO3 catalyst activity in OCM reaction. A precious pH control should be required to prepare various perovskite catalysts for the OCM.

关键词： LaAlO3 Perovskite Oxidative coupling of methane Co-precipitation pH value

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Irritable bowel syndrome:Emerging paradigm in pathophysiology

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World Journal of Gastroenterology 2014年第10期20卷 2456-2469页

作者： yoo Jin Lee Kyung Sik Park Division of Gastroenterology and Hepatology Department of Internal Medicine Keimyung University School of Medicine Daegu 700-712 South Korea

Irritable bowel syndrome(IBS)is one of the most common gastrointestinal disorders,characterized by abdominal pain,bloating,and changes in bowel *** symptoms cannot be explained by structural abnormalities and there is no specific laboratory test or biomarker for ***,IBS is classified as a functional disorder with diagnosis dependent on the history taking about manifested symptoms and careful physical *** a great deal of research has been carried out in this area,the pathophysiology of IBS is complex and not completely *** factors are thought to contribute to the symptoms in IBS patients;altered gastrointestinal motility,visceral hypersensitivity,and the brain-gut interaction are important classical concepts in IBS *** areas of research in this arena include inflammation,postinfectious low-grade inflammation,genetic and immunologic factors,an altered microbiota,dietary factors,and enteroendocrine *** emerging studies have not shown consistent results,provoking controversy in the IBS ***,certain lines of evidence suggest that these mechanisms are important at least a subset of IBS patients,confirming that IBS symptoms cannot be explained by a single etiological ***,it is important to keep in mind that IBS requires a more holistic approach to determining effective treatment and understanding the underlying mechanisms.

关键词： Pathophysiology Irritable bowel syndrome Inflammation Immunologic Genetics Microbiota Diet Enteroendocrine cell

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Applying Machine Learning Techniques for Religious Extremism Detection on Online User Contents

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Computers, Materials & Continua 2022年第1期70卷 915-934页

作者： Shynar Mussiraliyeva Batyrkhan Omarov Paul yoo Milana Bolatbek Al-Farabi Kazakh National University AlmatyKazakhstan CSIS Birkbeck CollegeUniversity of LondonLondonUK

In this research paper,we propose a corpus for the task of detecting religious extremism in social networks and open sources and compare various machine learning algorithms for the binary classification problem using a previously created corpus,thereby checking whether it is possible to detect extremist messages in the Kazakh *** do this,the authors trained models using six classic machine-learning algorithms such as Support Vector Machine,Decision Tree,Random Forest,K Nearest Neighbors,Naive Bayes,and Logistic *** increase the accuracy of detecting extremist texts,we used various characteristics such as Statistical Features,TF-IDF,POS,LIWC,and applied oversampling and undersampling techniques to handle imbalanced *** a result,we achieved 98%accuracy in detecting religious extremism in Kazakh texts for the collected *** the developed machine learningmodels in various databases that are often found in everyday life“Jokes”,“News”,“Toxic content”,“Spam”,“Advertising”has also shown high rates of extremism detection.

关键词： Extremism religious extremism machine learning social media social network natural language processing NLP

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Sensitivity evaluation of the flash flood warning system introduced to ungauged small mountainous basins in Korea

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Journal of Mountain Science 2019年第5期16卷 971-993页

作者： yoo Chulsang LEE Jinwook CHANG Kwonhee YANG Dongmin School of Civil Environmental and Architectural Engineering College of Engineering Korea University NOAA SNC Co. Ltd.

This study evaluates the uncertainty involved in the determination of the flash flood guidance(FFG) of the flash flood warning system(FFWS) for a small mountainous region(FFWS_MR)in Korea. The sensitivity is evaluated both at each step to determine the FFG and for all steps together. The results show that the relative difference of the FFG is about 50% of the current system, most of which involves the channel width. Especially, the use of some specific empirical equations to estimate the major parameters results in a considerable amount of the relative difference of the FFG. In addition, though only four basins were field-surveyed, it is found that the indirect estimation of the major parameters always introduces some amount of additional uncertainty. In conclusion, accurate estimation of the major parameters must be the most important procedure to derive an accurate FFG, among which the channel cross-section at the exit of the basin lies at the center.

关键词： Flash flood warning system Flash flood guidance Sensitivity analysis

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Real-Time Demand Response Management for Controlling Load Using Deep Reinforcement Learning

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Computers, Materials & Continua 2022年第12期73卷 5671-5686页

作者： Yongjiang Zhao Jae Hung yoo Chang Gyoon Lim Department of Computer Engineering Chonnam National UniversityYeosu59626Korea

With the rapid economic growth and improved living standards,electricity has become an indispensable energy source in our ***,the stability of the grid power supply and the conservation of electricity is *** following are some of the problems facing now:1)During the peak power consumption period,it will pose a threat to the power *** and improving the power distribution infrastructure requires high maintenance costs.2)The user’s electricity schedule is unreasonable due to personal behavior,which will cause a waste of *** load as a vital part of incentive demand response(DR)can achieve rapid response and improve demand-side *** load by manually formulating rules,some devices are selective to be adjusted during peak power ***,it is challenging to optimize methods based on manual *** paper uses SoftActor-Critic(SAC)as a control algorithm to optimize the control *** results show that through the coordination of the SAC to control load in CityLearn,realizes the goal of reducing both the peak load demand and the operation costs on the premise of regulating voltage to the safe limit.

关键词： Demand response controlling load SAC CityLearn

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Discontinuation of antiplatelet therapy after stent-assisted coil embolisation of cerebral aneurysm:a nationwide cohort study

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Stroke & Vascular Neurology 2024年第5期9卷 560-567页

作者： Minyoul Baik Jimin Jeon Jinkwon Kim Joonsang yoo Department of Neurology Yongin Severance HospitalYonsei University College of MedicineYongin-siGyeonggi-doKorea(the Republic of)

Introduction Stent-assisted coil embolisation(SACE)for the treatment of unruptured cerebral aneurysms has been increasingly ***-term advantages of antiplatelet therapy(APT)post-SACE treatment are still not well *** investigated the long-term effects of APT on clinical prognosis after *** and methods We conducted a retrospective study using nationwide health insurance claims data from South Korea,including patients with cerebral aneurysm treated with SACE from January 2009 to December *** study outcomes consisted of the occurrence of cerebral infarction and major *** evaluate the impact of APT,we employed a multivariable time-dependent Cox proportional hazards regression model for each of the three distinct periods:1–12 months,12–24 months and>24 months after *** This study included 17692 unruptured cerebral aneurysm patients treated with *** the mean follow-up of 4.2 years,there were 379(2.1%)patients with cerebral infarction and 190(1.1%)patients with major *** percentage of patients receiving APT was 79.5%at 1year,which gradually decreased to 58.3%at 2 years after *** was beneficial in preventing cerebral infarction within 12 months after SACE(adjusted HR(aHR)0.56;95%CI,0.35 to 0.89;p=0.014).After 12 months,this association was not *** increased the risk of haemorrhage after 24 months(aHR 1.76;95%CI 1.11 to 2.87;p=0.016).Discussion and conclusion Our findings suggest that in patients with unruptured cerebral aneurysm treated with SACE,the reasonable duration of APT for preventing cerebral infarction might be 1year after SACE.

关键词： cerebral aneurysm nationwide

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Error resilient concurrent video streaming over wireless mesh networks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 684-695页

作者： CHUAH Chen-nee yoo Ben S.J. Electrical and Computer Engineering Department University of California Davis 95616 USA Electrical and Computer Engineering Department

In this paper, we propose a multi-source multi-path video streaming system for supporting high quality concurrent video-on-demand (VoD) services over wireless mesh networks (WMNs), and leverage forward error correction to enhance the error resilience of the system. By taking wireless interference into consideration, we present a more realistic networking model to capture the characteristics of WMNs and then design a route selection scheme using a joint rate/interference-distortion optimiza- tion framework to help the system optimally select concurrent streaming paths. We mathematically formulate such a route selec- tion problem, and solve it heuristically using genetic algorithm. Simulation results demonstrate the effectiveness of our proposed scheme.

关键词： Wireless mesh network, Concurrent video streaming, Interference

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Slip-enhanced Reverse Electrodialytic Power Generation in Ion-selective Nanochannels

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Journal of Thermal Science 2013年第1期22卷 36-41页

作者： Byeongdong Kang Jaisuk yoo Hyun Jung Kim Dong-Kwon Kim Department of Mechanical Engineering Ajou University

Power generation by reverse electrodialysis in ion-selective nanochannels is numerically investigated. Especially,in the present study, the influence of hydrodynamic slip at the surface of nanochannels is investigated. The current-potential characteristics of the nanochannels are calculated by solving several governing equations:Nernst-Planck equation for the ionic concentrations, the Poisson equation for the electric potential, and the Navier-Stokes equation for the diffusioosmotic flow. Hydrodynamic slip is applied as the boundary condition at the surface of nanochannels. As the slip length increases, the diffusioosmotic flow velocity and electrical conductance of ions increase because the friction at the surface of nanochannels decreases. It is shown that the power generation is enhanced by 44% with a moderate 100nm slip length by using a nanochannel with 10nm height.

关键词： Reverse electrodialysis Ion-selective nanochannel Power generation Slip length

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Less common neoplasms of the pancreas

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World Journal of Gastroenterology 2006年第20期12卷 3180-3185页

作者： Abby L Mulkeen Peter S yoo Charles Cha Department of Surgery Yale University School of Medicine New HavenCT and the VACT Healthcare SystemWest HavenCT330 Cedar StreetLH 118PO Box 208062New HavenCT06520-8062United States

Recently, there has been an increased recognition of neoplasms of the pancreas other than ductal adenocarcinorna. Although not as well studied or characterized as pancreatic adenocarcinorna there are many distinct lesions which exhibit diverse biological behaviors and varying degrees of malignancy. These lesions include： endocrine neoplasms, cystic tumors, solid pseudopapillary tumors, acinar cell carcinoma, squamous cell carcinoma, primary lymphoma of the pancreas, and metastatic lesions to the pancreas. These less common neoplasms are being diagnosed more frequently as the number and sensitivity of diagnostic imaging studies increase. This review article discusses the clinical course, diagnosis, and treatment of these less common, but quite relevant, neoplasms of the pancreas.

关键词： Pancreas Neoplasms Ductal adenocarcinoma

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