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Fractal Analysis of Rainfall-Induced Landslide and Debris Flow Spread Distribution in the Chenyulan Creek Basin, Taiwan

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Journal of Earth Science 2016年第1期27卷 151-159页

作者： Zon-yee Yang Hamid Reza Pourghasemi Yen-Hung Lee Department of Civil Engineering Tamkang University Department of Natural Resources and Environmental Engineering College of Agriculture Shiraz University

The Chenyulan Stream in Central Taiwan follows the Chenyulan fault line which is a major boundary fault in Taiwan. In recent years, many destructive landslides have occurred in the Chenyulan Creek Basin after heavy rainfall accompanied by several strong typhoons. Three examples of landslide distributions in the Chenyulan Creek Basin, before and after 1996 and after 2004 are analyzed. The box dimension and two-point correlation dimension are employed to describe the landslide area size distribution and distance distribution between every two landslides, respectively. It is found that the number of landslides increased in this period. However, the average landslide area decreased. The correlation dimension gradually increased from 1.15 to 1.32 during this period（before and after 1996 and after 2004）. This implies that the landslide distribution in the Chenyulan Creek Basin has become diffuse and extensive. The box dimension value shows the degree of the landslide density occupied in a space. The box dimension also increased from 0.3 to 0.69 during this period. The increasing box dimension means that the landslide presented in this creek basin has gradually increased. This indicates that the slopes of this creek basin have become more unstable and susceptible.

关键词： landslide distribution box dimension two-point correlation dimension Taiwan.

Current therapy of hilar cholangiocarcinoma

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Hepatobiliary & Pancreatic Diseases International 2012年第1期11卷 12-17页

作者： Stephanie Hiu Yan Lau Wan yee Lau Faculty of Medicine The Chinese University of Hong Kong

BACKgROUND: Hilar cholangiocarcinoma (HC) is an adeno-carcinoma of the extrahepatic biliary tree arising from the main left or right hepatic ducts or their confluence. This tumor is still considered to be difficult to treat or to cure. DATA SOURCES: We reviewed the medical literature on HC. Relevant and updated information on this tumor was analyzed in a concise and easy-to-read manner. The article is not intended to be a systematic review, but an extensive search was conducted on PubMed and MEDLINE using the keywords 'hilar cholangiocarcinoma' and 'Klatskin tumor' until July 2011. RESULTS: The selection and the timing of management options for patients with HC are determined by the degree of certainty of the diagnosis, the general condition of the patients, the underlying liver function and the stage of the disease. Current treatment of HC can be divided into curative and palliative treatment. For the curative treatment, local excision should only be used on small tumors which are confined to the bile duct wall and Bismuth I papillary carcinoma. Partial hepatectomy should be combined with caudate lobe resection and porta-hepatis lymph node dissection. The results of these major resections can be improved with portal vein embolization, and staging laparoscopy and laparoscopic ultrasound. The role of preoperative biliary drainage is controversial. Autotransplantation for HC gave disappointing results while the Mayo Protocol of chemoradiation for selecting patients with unresectable HC for orthotopic liver transplantation has been widely accepted. Palliative treatment included bypass surgery, endoscopic or percutaneous stenting, photodynamic therapy, intraluminal brachytherapy, and external radiation and systemic therapy. CONCLUSIONS: Adequate surgery with R0 resection should be the main goal of treatment. For patients with unresectable HC, treatment aims to improve the quality and quantity of their survival.

关键词： hilar cholangiocarcinoma Klatskin tumor resection liver transplantation palliative treatment

Development of a system configuration for a solar powered hydrogen facility using fuzzy logic control

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第11期14卷 822-834页

作者： Ying-tai LOONg Mahidzal DAHARI Hwa-jen YAP Hue-yee CHONg Department of Mechanical Engineering Faculty of Engineering University MalayaKuala Lumpur 50603 Malaysia

Solar energy is a natural resource which can be harnessed to provide clean electricity for hydrogen production ***, this technology is not widely used because of control issues, particularly for hydrogen refuelling stations. At present,direct or DC-DC converter couplings are the most common system configurations for hydrogen refuelling stations. However, these system configurations are costly and suffer from gas shortage at hydrogen refuelling stations. Furthermore, the hydrogen produced by such system configurations varies considerably depending on the levels of solar radiation. In order to address these issues, a new system configuration is proposed, incorporating the feedback signal of the storage level in the control system. The photovoltaic(PV) system, electrolyzer, and storage tank are integrated with a fuzzy logic controller(FLC) to determine the backup current compensation for electrolyzer operation in order to obtain the minimum power required for hydrogen production. The proposed FLC is constructed with three input variables which are the PV current, hydrogen storage level, and the battery state of charge. The rules-based fuzzy inference process is based on the proposed configuration which combines the advantages of direct and DC-DC converter coupling configurations. The simulation results show that the proposed configuration offers better adaptability to variable radiation conditions compared to other methods. This gives a more promising option for ensuring the adequacy of hydrogen supply at hydrogen refuelling stations.

关键词： Hydrogen energy Solar energy Hydrogen refueling facility Fuzzy logic

Noise robustness of an operational modal-based structural damage-detection scheme using impact-synchronous modal analysis

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浙江大学学报(英文版)A辑:应用物理与工程 2023年第9期24卷 782-800页

作者： Pei Yi SIOW Zhi Chao ONg Shin yee KHOO Kok-Sing LIM Department of Mechanical Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur 50603Malaysia Photonics Research Centre Deputy Vice Chancellor(Research and Innovation)OfficeUniversiti MalayaKuala Lumpur 50603Malaysia

Data-driven damage-detection schemes are usually unsupervised machine-learning models in practice,as these do not require any ***-based features are commonly used in these schemes but often require several other parameters to accurately correlate with damage,as they may not globally represent the model,making them less sensitive to *** data,such as frequency response functions(FRFs)and principal component analysis(PCA)reduced FRFs(PCA-FRFs),inherits the dynamic characteristics of the structure,and it changes when damage occurs,thus showing sensitivity to ***,noise from the environment or external sources such as wind,operating machines,or the in-service system itself,can reduce the modal data's sensitivity to damage if not handled properly,which affects damage-detection *** study proposes a noise-robust operational modal-based structural damage-detection scheme that uses impact-synchronous modal analysis(ISMA)to generate clean,static-like FRFs for damage *** allows modal data collection without requiring shutdown conditions,and its denoising feature aids in generating clean,static-like FRFs for damage *** results showed that the FRFs obtained through ISMA under noise conditions have frequency response assurance criterion(FRAC)and cross signature assurance criterion(CSAC)scores greater than 0.9 when compared with FRFs obtained through experimental modal analysis(EMA)under static conditions;this validates the denoising feature of *** the denoised FRFs are reduced to PCA-FRFs and used in an unsupervised learning-based damage-detection scheme,zero false alarms occur.

关键词： Impact-synchronous modal analysis(ISMA) Frequency response function(FRF) Principal component analysis(PCA) Unsupervised learning Damage detection

Isolated gallbladder tuberculosis mimicking acute cholecystitis:A case report

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World Journal of gastrointestinal Surgery 2020年第3期12卷 123-128页

作者： Kai Siang Chan Vishal g Shelat Cher Heng Tan yee Lin Tang Sameer P Junnarkar Kong Chian School of Medicine Nanyang Technological UniversitySingapore 308232Singapore Department of general Surgery Tan Tock Seng HospitalSingapore 308433Singapore Department of Diagnostic Radiology Tan Tock Seng HospitalSingapore 308433Singapore Department of Pathology Tan Tock Seng HospitalSingapore 308433Singapore

BACKgROUND Isolated tuberculosis of the gallbladder is extremely rare due to its intrinsic resistance to tuberculous *** are reports of gallbladder tuberculosis mimicking cholecystitis or ***,these presentations were *** diagnosis of gallbladder tuberculosis warrants the need for investigation of additional sites of inoculation and contact tracing of all tuberculosis *** tuberculosis is a rare entity but should be suspected in patients from endemic regions with risk factors such as underlying immunosuppression or history of *** SUMMARY We present a case of gallbladder tuberculosis presenting as acute cholecystitis.A 44-year-old Filipino lady presented with a 11-d history of right hypochondrium and epigastric pain which worsened after meals with no significant past medical *** underwent laparoscopic cholecystectomy on the presumptive diagnosis of acute cholecystitis and diagnosed as gallbladder tuberculosis after histopathological *** patient did not have features of pulmonary or systemic tuberculosis nor was she *** recovered *** was subsequently discharged and followed-up at a hospital in her home country due to financial and social *** Clinicians should have a high index of suspicion for patients in endemic regions presenting with cholecystitis.

关键词： Cholecystectomy Cholecystitis gallbladder Extra-pulmonary tuberculosis Case report

Construction of Conservative Numerical Fluxes for the Entropy Split Method

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Communications on Applied Mathematics and Computation 2023年第2期5卷 653-678页

作者： Björn Sjögreen H.C.yee Multid Analyses AB GothenburgSweden NASA Ames Research Center Moffett FieldCA 94035USA

The entropy split method is based on the physical entropies of the thermally perfect gas Euler *** Euler flux derivatives are approximated as a sum of a conservative portion and a non-conservative portion in conjunction with summation-by-parts(SBP)difference boundary closure of(gerritsen and Olsson in J Comput Phys 129:245-262,1996;Olsson and Oliger in RIACS Tech Rep 94.01,1994;yee et *** J Comp Phys 162:33-81,2000).Sj?green and yee(J Sci Comput)recently proved that the entropy split method is entropy conservative and ***-ard high-order spatial central differencing as well as high order central spatial dispersion relation preserving(DRP)spatial differencing is part of the entropy stable split methodol-ogy *** current work is our first attempt to derive a high order conservative numerical flux for the non-conservative portion of the entropy splitting of the Euler flux *** to the construction,this conservative numerical flux requires higher oper-ations count and is less stable than the original semi-conservative split ***,the Tadmor entropy conservative(EC)method(Tadmor in Acta Numerica 12:451-512,2003)of the same order requires more operations count than the new *** the entropy split method is a semi-conservative skew-symmetric splitting of the Euler flux derivative,a modified nonlinear filter approach of(yee et *** J Comput Phys 150:199-238,1999,J Comp Phys 162:3381,2000;yee and Sj?green in J Comput Phys 225:910934,2007,High Order Filter Methods for Wide Range of Compressible flow *** of the ICOSAHOM09,June 22-26,Trondheim,Norway,2009)is proposed in conjunction with the entropy split method as the base method for problems containing shock ***-time integration of 2D and 3D test cases is included to show the com-parison of these new approaches.

关键词： Finite-difference method Entropy conservation Entropy splitting Shock capturing

Amine-based solvent for CO_2 absorption and its impact on carbon steel corrosion: A perspective review

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1357-1367页

作者： Zhe Lun Ooi Pui yee Tan Lian See Tan Swee Pin Yeap Department of Chemical&Petroleum Engineering Faculty of EngineeringTechnology&Built EnvironmentUCSI University56000Cheras Kuala LumpurMalaysia Department of Chemical Process Engineering Malaysia–Japan International Institute of TechnologyUniversiti Teknologi MalaysiaJalan Sultan Yahya Petra54100 Kuala LumpurMalaysia

Carbon dioxide(CO2)is one of the commonly emitted gaseous by-products in industrial *** CO2 gas is the main cause to greenhouse effect,various CO2 capture technologies have been proposed and implemented to sequester the CO2 before the waste gases being released into the *** of the mature technologies for CO2 absorption is by using amine-based *** this regard,different single amine solvents or blended amine solvents have been proven for their capability to remove ***,the dissolution and reaction of CO2 gas with the amine solvents turn the solution *** phenomenon is undesired as it posts corrosion problem to the absorption column,which normally built of carbon steel ***,understanding the behaviour of different amine-based solvents in absorbing CO2 and its subsequent impact on carbon steel corrosion is very *** this review article,we will outline some of the more commonly used solvents and their respective advantages and disadvantages,motivating further investigation into the corrosion ***,existing gaps in this research area are discussed for future investigation.

关键词： greenhouse gases PCCC technology Amine solvent Corrosion rate Carbon steel

Incipient motion of cohesionless sediments on riverbanks with ground water injection

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International Journal of Sediment Research 2012年第1期27卷 111-119页

作者： Yan LU Yong-jun LU yee-meng CHIEW Nanjing Hydraulic Research Institute State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering School of Civil and Environmental Engineering Nanyang Technological Univ.

This study investigates the influence of ground water injection on the initial movement of non-cohesive sediment particles on a riverbank slope analytically and *** including the hydraulic gradient in the force analysis,the critical condition was derived to account for the effect of seepage flow, showing that the seepage hydraulic gradient and the riverbank slope are governing parameters in modifying the incipient motion of sediments on a riverbank *** investigations were performed in an open-channel flume for various riverbank slopes and hydraulic gradients of injection, showing that the critical shear stress increases with decreasing riverbank slopes and vise-versa,while injection reduces the critical *** experimental data agree well with the theoretical derived expression of the critical condition in the case of injection.

关键词： Incipient motion Riverbank Injection Sediment Seepage

Variable High Order Multiblock Overlapping grid Methods for Mixed Steady and Unsteady Multiscale Viscous Flows

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Communications in Computational Physics 2009年第2期5卷 730-744页

作者： Bjorn Sjogreen H.C.yee Center for Applied Scientific Computing Lawrence Livermore National LaboratoryLivermoreCA 94551USA NASA Ames Research Center Moffett FieldCA 94035USA

Flows containing steady or nearly steady strong shocks on parts of the flow field,and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme,even under the multiblock grid or adaptive grid refinement *** sixthorder or higher-order shock-capturing methods are appropriate for unsteady turbulence with shocklets,third-order or lower shock-capturing methods are more effective for strong steady or nearly steady shocks in terms of *** order to minimize the short comings of low order and high order shock-capturing schemes for the subject flows,a multiblock overlapping grid with different types of spatial schemes and orders of accuracy on different blocks is *** recently developed single block high order filter scheme in generalized geometries for Navier Stokes and magnetohydrodynamics systems is extended to multiblock overlapping grid *** first stage in validating the high order overlapping approach with several test cases is included.

关键词： Multiblock grid overset grids high order numerical methods blunt body hypersonic flows mixed steady and unsteady flows