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Prediction of lining response for twin tunnels constructed in anisotropic clay using machine learning techniques

Underground Space 2022年第1期7卷 122-133页

作者： Wengang Zhang Yongqin Li Chongzhi Wu Hongrui Li atc goh Hanlong Liu School of Civil Engineering Chongqing UniversityChongqing 400045China National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore

Excessive structural forces generated inside tunnel linings could affect the safety and serviceability of tunnels,emphasizing the need to accurately predict the forces acting on tunnel linings during the preliminary design *** this study,an anisotropic soil model devel-oped by Norwegian Geotechnical Institute(NGI)based on the Active-Direct shear-Passive concept(NGI-ADP model)was adopted to conduct finite element(FE)analyses.A total of 682 cases were modeled to analyze the effects of five key parameters on twin-tunnel struc-tural forces;these parameters included twin-tunnel arrangements and subsurface soil properties:burial depth H,tunnel center-to-center distance D,soil strength s_(u)^(A),stiffness ratio G_(u)=s_(u)^(A),and degree of anisotropy ss_(u)^(P)=s_(u)^(A).The significant factors contributing to the bending moment and thrust force of the linings were the tunnel distance and overlying soil depth,*** degree of anisotropy of the surrounding soil was found to be extremely important in simulating the twin-tunnel construction,and severe design errors could be made if the soil anisotropy is ignored.A cutting-edge application of machine learning in the construction of twin tunnels is presented;multivariate adaptive regression splines and decision tree regressor methods are developed to predict the maximum bending moment within the first tunnel’s linings based on the constructed FE *** developed prediction model can enable engineers to estimate the structural response of twin tunnels more accurately in order to meet the specific target reliability indices of projects.

关键词： Twin tunnel Bending moment Thrust force Multivariate adaptive regression splines Decision tree regressor

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Inverse reliability analysis and design for tunnel face stability considering soil spatial variability

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1552-1564页

作者： Zheming Zhang Jian Ji Xiangfeng Guo Siang Huat goh Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing210098China Department of Civil and Environmental Engineering National University of SingaporeSingapore

The traditional deterministic analysis for tunnel face stability neglects the uncertainties of geotechnical parameters,while the simplified reliability analysis which models the potential uncertainties by means of random variables usually fails to account for soil spatial *** overcome these limitations,this study proposes an efficient framework for conducting reliability analysis and reliability-based design(RBD)of tunnel face stability in spatially variable soil *** three-dimensional(3D)rotational failure mechanism of the tunnel face is extended to account for the soil spatial variability,and a probabilistic framework is established by coupling the extended mechanism with the improved Hasofer-Lind-Rackwits-Fiessler recursive algorithm(iHLRF)as well as its inverse analysis *** proposed framework allows for rapid and precise reliability analysis and RBD of tunnel face *** demonstrate the feasibility and efficacy of the proposed framework,an illustrative case of tunnelling in frictional soils is presented,where the soil's cohesion and friction angle are modelled as two anisotropic cross-correlated lognormal random *** results show that the proposed method can accurately estimate the failure probability(or reliability index)regarding the tunnel face stability and can efficiently determine the required supporting pressure for a target reliability index with soil spatial variability being taken into ***,this study reveals the impact of various factors on the support pressure,including coefficient of variation,cross-correlation between cohesion and friction angle,as well as autocorrelation distance of spatially variable soil *** results also demonstrate the feasibility of using the forward and/or inverse first-order reliability method(FORM)in high-dimensional stochastic *** is hoped that this study may provide a practical and reliable framework for determining the stability of tunnels in complex

关键词： Limit analysis Tunnel face stability Spatial variability HLRF algorithm Inverse reliability method

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1,3-Dipolar Cycloaddition of Polycyclic Aromatic Azomethine Ylides and Alkynylbenziodoxoles for Synthesis of Functional Dibenzoullazines

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Chinese Journal of Chemistry 2024年第10期42卷 1079-1083页

作者： Hui Han Glen Wee Zhuan goh Yongxin Li Naohiko Yoshikai Shingo Ito Schoolof Chemistry ChemicalEngineering and BiotechnologyNanyang Technoogical University21 Nanyang LinkSingapore 637371Singapore Graduate School of Pharmaceutical Sciences Tohoku UniversitySendai 980-8578Japan

A new family of dibenzoullazine derivatives was synthesized through 1,3-dipolar cycloaddition of polycyclic aromatic azomethine ylides with alkynylbenziodoxoles followed by *** benziodoxole moiety in the resulting products was used as a versatile linchpin for the synthesis of structurally diverse functional dibenzoullazines that are difficult to access by other synthetic methods.

关键词： Cycloaddition Nitrogen heterocycles Azomethine ylides Hypervalent compounds Dibenzoullazine

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An Implementation of Multiscale Line Detection and Mathematical Morphology for Efficient and Precise Blood Vessel Segmentation in Fundus Images

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Computers, Materials & Continua 2024年第5期79卷 2565-2583页

作者： Syed Ayaz Ali Shah Aamir Shahzad Musaed Alhussein Chuan Meng goh Khursheed Aurangzeb Tong Boon Tang Muhammad Awais Department of Electrical and Computer Engineering COMSATS University IslamabadAbbottabad CampusAbbottabad22060Pakistan Department of Computer Engineering College of Computer and Information SciencesKing Saud UniversityP.O.Box 51178Riyadh11543Saudi Arabia Faculty of Information and Communication Technology University Tunku Abdul RehmanKampar CampusKampar31900Malaysia Centre for Intelligent Signal and Imaging Research University Teknologi PETRONASBandar Seri IskandarPerak32610Malaysia School of Computing Sciences University of East AngliaNorwichNR47TJUK

Diagnosing various diseases such as glaucoma,age-related macular degeneration,cardiovascular conditions,and diabetic retinopathy involves segmenting retinal blood *** task is particularly challenging when dealing with color fundus images due to issues like non-uniformillumination,low contrast,and variations in vessel appearance,especially in the presence of different ***,the speed of the retinal vessel segmentation system is of utmost *** the surge of now available big data,the speed of the algorithm becomes increasingly important,carrying almost equivalent weightage to the accuracy of the *** address these challenges,we present a novel approach for retinal vessel segmentation,leveraging efficient and robust techniques based on multiscale line detection and mathematical *** algorithm’s performance is evaluated on two publicly available datasets,namely the Digital Retinal Images for Vessel Extraction dataset(DRIVE)and the Structure Analysis of Retina(STARE)*** experimental results demonstrate the effectiveness of our method,withmean accuracy values of 0.9467 forDRIVE and 0.9535 for STARE datasets,aswell as sensitivity values of 0.6952 forDRIVE and 0.6809 for STARE ***,our algorithmexhibits competitive performance with state-of-the-art ***,it operates at an average speed of 3.73 s per image for DRIVE and 3.75 s for STARE *** is worth noting that these results were achieved using Matlab scripts containing multiple *** suggests that the processing time can be further reduced by replacing loops with *** the proposed algorithm can be deployed in real time *** summary,our proposed system strikes a fine balance between swift computation and accuracy that is on par with the best available methods in the field.

关键词： Line detector vessel detection localization mathematical morphology image processing

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Recent advances in graphene-based phase change composites for thermal energy storage and management

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Nano Materials Science 2024年第2期6卷 115-138页

作者： Qiang Zhu Pin Jin Ong Si Hui Angela goh Reuben J.Yeo Suxi Wang Zhiyuan Liu Xian Jun Loh Institute of Materials Research and Engineering A*STAR(Agency for ScienceTechnology and Research)2 Fusionopolis WayInnovis#08-03138634Singapore Institute of Sustainability for Chemicals Energy and EnvironmentA*STAR(Agency for ScienceTechnology and Research)1 Pesek RoadJurong Island627833Singapore School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological University21 Nanyang Link637371Singapore Shenzhen Institutes of Advanced Technology(SIAT) Chinese Academy of Sciences(CAS)1068 Xueyuan AvenueShenzhen518055China Department of Material Science and Engineering National University of Singapore9 Engineering Drive 1#03-09 EA117575Singapore

Energy storage and conservation are receiving increased attention due to rising global energy ***,the development of energy storage materials is *** energy storage(TES)systems based on phase change materials(PCMs)have increased in prominence over the past two decades,not only because of their outstanding heat storage capacities but also their superior thermal energy regulation ***,issues such as leakage and low thermal conductivity limit their applicability in a variety of ***-based materials such as graphene and its derivatives can be utilized to surmount these *** study examines the recent advancements in graphene-based phase change composites(PCCs),where graphene-based nanostructures such as graphene,graphene oxide(GO),functionalized graphene/GO,and graphene aerogel(GA)are incorporated into PCMs to substantially enhance their shape stability and thermal conductivity that could be translated to better storage capacity,durability,and temperature response,thus boosting their attractiveness for TES *** addition,the applications of these graphene-based PCCs in various TES disciplines,such as energy conservation in buildings,solar utilization,and battery thermal management,are discussed and summarized.

关键词： Phase change material Nanocomposites Solar energy Sustainable energy Thermo-regulation

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Ocular image-based deep learning for predicting refractive error:A systematic review

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Advances in Ophthalmology Practice and Research 2024年第3期4卷 164-172页

作者： Samantha Min Er Yew Yibing Chen Jocelyn Hui Lin goh David Ziyou Chen Marcus Chun Jin Tan Ching-Yu Cheng Victor Teck Chang Koh Yih Chung Tham Department of Ophthalmology Yong Loo Lin School of MedicineNational University of SingaporeSingapore Centre for Innovation and Precision Eye Health Yong Loo Lin School of MedicineNational University of SingaporeSingapore School of Chemistry Chemical Engineeringand BiotechnologyNanyang Technological UniversitySingapore Singapore Eye Research Institute Singapore National Eye CentreSingapore Department of Ophthalmology National University HospitalSingapore Ophthalmology and Visual Sciences(Eye ACP) Duke-NUS Medical SchoolSingapore

ackground:Uncorrected refractive error is a major cause of vision impairment worldwide and its increasing prevalent necessitates effective screening and management ***,deep learning,a subset of Artificial Intelligence,has significantly advanced ophthalmological diagnostics by automating tasks that required extensive clinical *** recent studies have investigated the use of deep learning models for refractive power detection through various imaging techniques,a comprehensive systematic review on this topic is has yet be *** review aims to summarise and evaluate the performance of ocular image-based deep learning models in predicting refractive *** text:We search on three databases(PubMed,Scopus,Web of Science)up till June 2023,focusing on deep learning applications in detecting refractive error from ocular *** included studies that had reported refractive error outcomes,regardless of publication *** systematically extracted and evaluated the continuous outcomes(sphere,SE,cylinder)and categorical outcomes(myopia),ground truth measurements,ocular imaging modalities,deep learning models,and performance metrics,adhering to PRISMA *** studies were identified and categorised into three groups:retinal photo-based(n=5),OCT-based(n=1),and external ocular photo-based(n=3).For high myopia prediction,retinal photo-based models achieved AUC between 0.91 and 0.98,sensitivity levels between 85.10%and 97.80%,and specificity levels between 76.40%and 94.50%.For continuous prediction,retinal photo-based models reported MAE ranging from 0.31D to 2.19D,and R^(2) between 0.05 and *** OCT-based model achieved an AUC of 0.79–0.81,sensitivity of 82.30%and 87.20%and specificity of 61.70%–68.90%.For external ocular photo-based models,the AUC ranged from 0.91 to 0.99,sensitivity of 81.13%–84.00%and specificity of 74.00%–86.42%,MAE ranges from 0.07D to 0.18D and accuracy ranges from 81.60%to 96.70%.The reported papers colle

关键词： Deep Learning Artificial Intelligence Refractive Error Retinal images Optical Coherence Tomography Photorefraction Ocular images Prediction

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Performance of pulsed plasma thruster at low discharge energy

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Plasma Science and Technology 2024年第4期26卷 122-132页

作者：李鸿俊林泽豪胡浩俊吴文东陈爱虹杜德扬 Department of Physics Faculty of ScienceUniversity of MalayaKuala Lumpur 50603Malaysia Faculty of Engineering The University of Nottingham Malaysia CampusSemenyih 43500Malaysia Faculty of Engineering Multimedia UniversityCyberjaya 63100Malaysia

As the size of satellites scales down, low-power and compact propulsion systems such as the pulsed plasma thruster(PPT) are needed for stabilizing these miniature satellites in orbit. Most PPT systems are operated at 2 J or more of discharge energy. In this work, the performance of a PPT with a side-fed, tongue-flared electrode configuration operated within a lower discharge energy range of 0.5-2.5 J has been investigated. Ablation and charring of the polytetrafluoroethylene propellant surface were analyzed through field-effect scanning electron microscopy imaging and energy-dispersive X-ray spectroscopy. When the discharge energy fell below 2 J, inconsistencies occurred in the specific impulse and the thrust efficiency due to the measurement of the low mass bit. At energy ≥2 J, the performance parameters are compared with other PPT systems of similar configuration and discussed in depth.

关键词： pulsed plasma thruster low discharge energy performance parameters

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Prevalence and risk factors for impaired renal function among Asian patients with nonalcoholic fatty liver disease

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Hepatobiliary & Pancreatic Diseases International 2024年第3期23卷 241-248页

作者： Chao Sun George Boon-Bee goh Wan-Cheng Chow Wah-Kheong Chan Grace Lai-Hung Wong Wai-Kay Seto Yi-Hsiang Huang Han-Chieh Lin I-Cheng Lee Hye Won Lee Seung Up Kim Vincent Wai-Sun Wong Jian-Gao Fan Center for Fatty Liver Disease Department of GastroenterologyXinhua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai Key Lab of Pediatric Gastroenterology and NutritionShanghai 200092China Department of Gastroenterology&Hepatology Singapore General HospitalSingaporeSingapore Gastroenterology and Hepatology Unit Department of MedicineFaculty of MedicineUniversity of MalayaKuala LumpurMalaysia Department of Medicine and Therapeutics and State Key Laboratory of Digestive Disease The Chinese University of Hong KongHong KongChina Department of Medicine The University of Hong KongHong KongChina Institute of Clinical Medicine National Yang Ming Chiao Tung University School of MedicineTaipeiTaiwanChina Division of Gastroenterology and Hepatology Taipei Veterans General HospitalTaipeiTaiwanChina Faculty of Medicine National Yang Ming Chiao Tung University School of MedicineTaipeiTaiwanChina Department of Internal Medicine Yonsei University College of MedicineSeoulKorea

Background:Nonalcoholic fatty liver disease(NAFLD)is associated with impaired renal function,and both diseases often occur alongside other metabolic ***,the prevalence and risk factors for impaired renal function in patients with NAFLD remain *** objective of this study was to identify the prevalence and risk factors for renal impairment in NAFLD ***:All adults aged 18-70 years with ultrasound-diagnosed NAFLD and transient elastography examination from eight Asian centers were enrolled in this prospective *** fibrosis and cirrhosis were assessed by FibroScan-aspartate aminotransferase(FAST),Agile 3+and Agile 4 *** renal function and chronic kidney disease(CKD)were defined by an estimated glomerular filtration rate(eGFR)with value of<90 mL/min/1.73 m^(2) and<60 mL/min/1.73 m^(2),respectively,as estimated by the CKD-Epidemiology Collaboration(CKD-EPI)***:Among 529 included NAFLD patients,the prevalence rates of impaired renal function and CKD were 37.4%and 4.9%,*** multivariate analysis,a moderate-high risk of advanced liver fibrosis and cirrhosis according to Agile 3+and Agile 4 scores were independent risk factors for CKD(P<0.05).Furthermore,increased fasting plasma glucose(FPG)and blood pressure were significantly associated with impaired renal function after controlling for the other components of metabolic syndrome(P<0.05).Compared with patients with normoglycemia,those with prediabetes[FPG≥5.6 mmol/L or hemoglobin A1c(HbA1c)≥5.7%]were more likely to have impaired renal function(P<0.05).Conclusions:Agile 3+and Agile 4 are reliable for identifying NAFLD patients with high risk of *** glycemic control in the prediabetic stage might have a potential renoprotective role in these patients.

关键词： Nonalcoholic fatty liver disease Impaired renal function Agile 3+ Agile 4 Metabolic syndrome

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Photodegradation of nitroaromatic compounds in aqueous solutions in the UV/H_2O_2 process

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Journal of Environmental Sciences 2005年第6期17卷 886-893页

作者： goh Ngoh Khang Division of Chemistry Nanyang Technological University l Nanyang Walk Singapore 637616

Photodegradation of nitrobenzene and nitrophenols in aqueous solutions by means of UV/H2 O2 process was studied in the Rayox batch reactors. Three nitrophenol isomers were identified as main photoproducts in the irradiated NB aqueous solutions. The distribution of nitrophenol isomers follows the order p-〉 m-〉 o-nitrophenol. Other intermediates detected include nitrohydroquinone, nitrocatechol, catechol, benzoquinone, phenol, nitrate/nitrite ions, formic acid, glyoxylic acid, maleic acid, oxalic acid and some aliphatic ketones and aldehydes. The degradation of nitrobenzene and nitrophenols at initial stages follows the first-order kinetics and the decay rate constants for nitrobenzene（NB） are around l0^-3-10^-2 s^-1 and for nitrophenols are around 10^-2 s^-1. The decomposition of H2 O2 in the presence of NB and each nitrophenol isomers follows zero-order kinetics. The quantum yields at initial stages for NB decay were estimated around 0.30 to 0.36, and for NPs decay is around 0.31-0.54.

关键词： photodegradation nitrobenzene nitrophenols UV/H2 O2 process

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Direct photolysis of nitroaromatic compounds in aqueous solutions

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Journal of Environmental Sciences 2005年第4期17卷 598-604页

作者： goh Ngoh Khang Division of Chemistry National Institute of Education Nanyang Technological University1 Nanyang WalkSingapore 637616

The direct photolysis of nitrobenzene and nitrophenols in aqueous solutions irradiated by polychromatic light were investigated. Several aromatic intermediates were identified as three nitrophenol isomers, nitrohydroquinone, nitrosobenzene, nitrocatechol, catechol and phenol. Nitrite and nitrate ions were also detected in the irradiated solution indicating direct photolysis of nitrobenzene or nitrophenols. The degradation of nitrobenzene and nitrophenols and the formation of three nitrophenol isomers were observed to follow zero-order kinetics. The quantum yields for nitrobenzene and nitrophenols removal are about 10~ -3 and 10~ -3 —10~ -4 respectively. The mechanism for nitrobenzene degradation was suggested to follow mainly nitro-nitrite intramolecular arrangement.

关键词： photodegradation photolysis nitrobenzene, nitrophenols

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