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Molecular characterization of polar heteroatom species in oilsands bitumen-derived vacuum residue fractions by Fourier transform ion cyclotron resonance mass spectrometry

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Petroleum Science 2019年第5期16卷 1196-1207页

作者： Fang Zheng Warren chung Eusebio Palmisano Dahai dong Quan Shi Zhiming Xu Keng H.chung State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China Well Resources Inc EdmontonCanada Cenovus Energy Inc CalgaryCanada Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of SciencesQingdao 266101China

A Canadian in situ oilsands bitumen-derived vacuum residue(VR)was subjected to supercritical fluid extraction and fractionation(SFEF)into 13 extractable fractions and an unextractable end-cut and characterized by positive-and negative-ion electrospray ionization(ESI)Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS).The results of negative-ion ESI FT-ICR MS showed that the N1 class species was the most abundant and the multifunctional group compounds,such as N1 O1,N1 O2,N1 S1,N1 S2,and N2 class species became abundant as the SFEF fraction became *** positive-ion ESI mode,the relative abundance of N1 class species decreased gradually in the heavy SFEF fractions while that of multifunctional group compounds *** relative abundance of N4 V1 O1 increased dramatically in heavy fractions and the *** distributions of polar heteroatom species of VR derived from oilsands bitumen were similar with those of VR derived from the Venezuela Orinoco extra heavy oil.

关键词： Molecular characterization Canadian oilsands bitumen SFEF ESI FT-ICR MS

Effects of Variable Thermal Conductivity and Non-linear Thermal Radiation Past an Eyring Powell Nanofluid Flow with Chemical Reaction

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Communications in Theoretical Physics 2017年第6期67卷 723-731页

作者： M.Ramzan M.Bilal Shamsa Kanwal Jae dong chung Department of Computer Science Bahria UniversityIslamabad Campus Department of Mathematics Faculty of ComputingCapital University of Science and Technology Department of Mathematical Sciences Fatima Jinnah Women University Department of Mechanical Engineering Sejong University

Present analysis discusses the boundary layer flow of Eyring Powell nanofluid past a constantly moving surface under the influence of nonlinear thermal radiation. Heat and mass transfer mechanisms are examined under the physically suitable convective boundary condition. Effects of variable thermal conductivity and chemical reaction are also considered. Series solutions of all involved distributions using Homotopy Analysis method(HAM) are *** of dominating embedded flow parameters are discussed through graphical illustrations. It is observed that thermal radiation parameter shows increasing tendency in relation to temperature profile. However, chemical reaction parameter exhibits decreasing behavior versus concentration distribution.

关键词： Eyring Powell nanofluid nonlinear thermal radiation convective boundary condition variable thermal conductivity chemical reaction

Semantic Segmentation by Using Down-Sampling and Subpixel Convolution: DSSC-UNet

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Computers, Materials & Continua 2023年第4期75卷 683-696页

作者： Young-Man Kwon Sunghoon Bae dong-Keun chung Myung-Jae Lim Department of Medical IT Eulji University553Sanseong-daeroSujeong-guSeongnam-siGyeonggi-do13135Korea

Recently, semantic segmentation has been widely applied toimage processing, scene understanding, and many others. Especially, indeep learning-based semantic segmentation, the U-Net with convolutionalencoder-decoder architecture is a representative model which is proposed forimage segmentation in the biomedical field. It used max pooling operationfor reducing the size of image and making noise robust. However, instead ofreducing the complexity of the model, max pooling has the disadvantageof omitting some information about the image in reducing it. So, thispaper used two diagonal elements of down-sampling operation instead ofit. We think that the down-sampling feature maps have more informationintrinsically than max pooling feature maps because of keeping the Nyquisttheorem and extracting the latent information from them. In addition,this paper used two other diagonal elements for the skip connection. Indecoding, we used Subpixel Convolution rather than transposed convolutionto efficiently decode the encoded feature maps. Including all the ideas, thispaper proposed the new encoder-decoder model called Down-Sampling andSubpixel Convolution U-Net (DSSC-UNet). To prove the better performanceof the proposed model, this paper measured the performance of the UNetand DSSC-UNet on the Cityscapes. As a result, DSSC-UNet achieved89.6% Mean Intersection OverUnion (Mean-IoU) andU-Net achieved 85.6%Mean-IoU, confirming that DSSC-UNet achieved better performance.

关键词： Semantic segmentation encoder-decoder U-Net DSSC-UNet subpixel convolution down-sampling

Mixed Convective Viscoelastic Nanofluid Flow Past a Porous Media with Soret–Dufour Effects

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Communications in Theoretical Physics 2016年第7期65卷 133-142页

作者： M.Ramzan Farhan Yousaf M.Farooq Jae dong chung Department of Computer Science Bahria University Department of Mathematics Faculty of Computing Capital University of Science and Technology Department of Mathematics Riphah International University Department of Mechanical Engineering Sejong University

The present study is carried out to see the thermal-diffusion(Dufour) and diffusion-thermo(Soret) effects on the mixed convection boundary layer flow of viscoelastic nanofluid flow over a vertical stretching surface in a porous medium. Optimal homotopy analysis method(OHAM) is best candidate to handle highly nonlinear system of differential equations obtained from boundary layer partial differential equations via appropriate transformations. Graphical illustrations depicting different physical arising parameters against velocity, temperature and concentration distributions with required discussion have also been added. Numerically calculated values of skin friction coefficient, local Nusselt and Sherwood numbers are given in the form of table and well argued. It is found that nanofluid velocity increases with increase in mixed convective and viscoelastic parameters but it decreases with the increasing values of porosity parameter. Also, it is observed that Dufour number has opposite behavior on temperature and concentration profiles.

关键词： mixed convection porous media nanofluid flow soret-dufour effects

Monitoring of non-point source pollutants load from a mixed forest land use

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Journal of Environmental Sciences 2010年第6期22卷 801-805页

作者： Sung Wan Yoon Se Woong chung dong Geun Oh Jae Woon Lee Department of Environmental Engineering Chungbuk National University Geum River Environmental Research Center National Institute of Environmental Research

The aim of this study was to determine the unit load of NPS （non-point source） pollutants including organic variables such as BOD （biochemical oxygen demand）, COD （chemical oxygen demand） and DOC （dissolved organic carbon）, nitrogen and phosphorus constituents, and suspended solids （SS） and their event mean concentration （EMC） of runoff flows from a water-shed of mixed forest land use by intensive field experiments. Field monitoring for continuous measurements of rainfall, flow, and water quality was conducted over 12 storm events during 2008-2009 using automated and manual sampling methods. The EMCs of individual runoff event were estimated for each water quality constituent based on the flow rate and concentration data of runoff discharge. The average EMCs of BOD, COD, DOC, SS, TN （total nitrogen）, NH4^＋-N, NO3^--N, TP （total phosphorus）, PO4^3-P from the mixed forest land were 1.794, 3.498, 1.462, 10.269, 0.862, 0.044, 0.634, 0.034, and 0.005 mg/L, respectively. The annual unit loads of BOD, COD, DOC, SS, TN, NH4^＋-N, NO3^--N, TP and PO4^3--P were estimated as 66.9, 133.2, 55.5, 429.8, 36.5, 1.6, 26.9, 1.3 and 0.1 kg/（ha·yr）, respectively. In addition, affecting parameters on the EMCs were investigated by statistic analysis of the field data. As a result, significant correlations with precipitation, rainfall intensity, and total runoff flows were found in most constituents.

关键词： event mean concentration mixed forest land use non-point source pollutant load unit load

Significant Lifetime Enhancement in QLEDs by Reducing Interfacial Charge Accumulation via Fluorine Incorporation in the ZnO Electron Transport Layer

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Nano-Micro Letters 2022年第12期14卷 432-446页

作者： dong Seob chung Tyler Davidson-Hall Giovanni Cotella Quan Lyu Peter Chun Hany Aziz Department of Electrical and Computer Engineering Waterloo Institute for NanotechnologyUniversity of Waterloo200 University Avenue WestWaterlooON N2L 3G1Canada Ipswich Research Centre Huawei Technologies Research&Development(UK)Ltd.Phoenix House(B55)Adastral ParkIpswich IP53REUK Ottawa IC Laboratory Huawei Canada19 Allstate ParkwayMarkhamON L3R 5B4Canada

ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in *** photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher *** findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.

关键词： Colloidal quantum dots Quantum dots light emitting device Device stability Zinc oxide nanoparticles Fluorine

Virtual reality-based cognitive-behavioural therapy for the treatment of anxiety in patients with acute myocardial infarction:a randomised clinical trial

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General Psychiatry 2024年第2期37卷 189-196页

作者： Yuanyuan Li Juan Peng Pingyuan Yang Jiajun Weng Yan'e Lu Jiajia Liu Shikun Xu Lihua Guan dong Huang Qibing Wang Juying Qian Zexin Zhao Yabin Wei Junbo Ge Xiao Huang Department of Psychological Medicine Zhongshan Hospital Fudan UniversityShanghaiChina Department of Cardiology Zhongshan HospitalFudan UniversityShanghai Institute of Cardiovascular DiseasesNational Clinical Research Center for Interventional MedicineShanghaiChina Department of Psychological Medicine Shanghai Geriatric Medical CenterShanghaiChina School of Nursing Peking UniversityBeijingChina Beijing Key Laboratory of Drug Dependence Research National Institute on Drug DependencePeking UniversityBeijingChina

Background The presence of mental health conditions is pervasive in patients who experienced acute myocardial infarction(AMI),significantly disrupting their *** timely and easily accessible psychological interventions using virtual reality-based cognitive-behavioural therapy(VR-CBT)could potentially improve both acute and long-term symptoms affecting their mental *** We aim to examine the effectiveness of VR-CBT on anxiety symptoms in patients with AMI who were admitted to the intensive care unit(ICU)during the acute stage of their *** In this single-blind randomised clinical trial,participants with anxiety symptoms who were admitted to the ICU due to AMI were continuously recruited from December 2022 to February *** who were Han Chinese aged 18-75 years were randomly assigned(1:1)via block randomisation to either the VR-CBT group to receive VR-CBT in addition to standard mental health support,or the control group to receive standard mental health support ***-CBT consisted of four modules and was delivered at the bedside over a 1-week *** were done at baseline,immediately after treatment and at 3-month *** intention-to-treat analysis began in june *** primary outcome measure was the changes in anxiety symptoms as assessed by the Hamilton Anxiety Rating Scale(HAM-A).Results Among 148 randomised participants,70 were assigned to the VR-CBT group and 78 to the control *** 1-week VR-CBT intervention plus standard mental health support significantly reduced the anxiety symptoms compared with standard mental health support alone in terms of HAM-A scores at both post intervention(Cohen’s d=−1.27(95%confidence interval(CI):−1.64 to−0.90,p<0.001)and 3-month follow-up(Cohen’s d=−0.37(95%CI:−0.72 to−0.01,p=0.024).Of the 70 participants who received VR-CBT,62(88.6%)completed the entire *** was the main reported adverse event(n=5).Conclusions Our results indicate that VR-CB

关键词： admitted behaviour treatment

Comparative study on discharge conditions in micro-hole electrical discharge machining of tungsten carbide (WC-Co) material

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中国有色金属学会会刊：英文版 2009年第B9期19卷 114-118页

作者： Hyun-Seok TAK Chang-Seung HA dong-Hyun KIM Ho-Jun LEE Hae-june LEE Myung-Chang KANG National Core Research Center for Hybrid Materials Solution Pusan National University Department of Electrical Engineering Pusan National University

WC-Co is used widely in die and mold industries due to its unique combination of hardness, strength and wear-resistance. For machining difficult-to-cut materials, such as tungsten carbide, micro-electrical discharge machining(EDM) is one of the most effective methods for making holes because the hardness is not a dominant parameter in EDM. This paper describes the characteristics of the discharge conditions for micro-hole EDM of tungsten carbide with a WC grain size of 0.5 μm and Co content of 12%. The EDM process was conducted by varying the condenser and resistance values. A R-C discharge EDM device using arc erosion for micro-hole machining was suggested. Furthermore, the characteristics of the developed micro-EDM were analyzed in terms of the electro-optical observation using an oscilloscope and field emission scanning electron microscope.

关键词：电火花加工碳化钨钴难切削材料硬质合金放电扫描电子显微镜微孔模具行业

A formally verified transformation to unify multiple nested clocks for a Lustre-like language

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Science China(Information Sciences) 2019年第1期62卷 208-210页

作者： Gang SHI Yucheng ZHANG Shu SHANG Shengyuan WANG Yuan dong Pen-chung YEW Department of Computer Science and Technology Tsinghua University Department of Computer Science and Engineering University of Minnesota

Multiple nested clocks is a major language feature in synchronous data-flow languages such as Lustre [1]. To build a formally verified compiler for such a language, it is a common practice to compile the source program to a C-like program first before compiling it to low-level machine-dependent code using a formally verified backend compiler

关键词： A formally verified transformation to unify multiple nested clocks for a Lustre-like language cycle