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Utilization of compressed natural gas for the production of carbon nanotubes

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Journal of Natural Gas Chemistry 2012年第6期21卷 620-624页

作者： Kim-Yang lee wei-Ming Yeoh Siang-Piao Chai Abdul Rahman Mohamed School of Chemical Engineering Engineering Campus Universiti Sains Malaysia Seri AmpanganNibong Tebal 14300 S. P. S. Pulau Pinang Malaysia School of Engineering Monash University Jalan Lagoon SelatanBandar Sunway 46150 Selangor Malaysia

The present work aims at utilizing compressed natural gas （CNG） as carbon source for the synthesis of carbon nanotubes （CNTs） over CoO-MoO/Al2O3 catalyst via catalytic chemical vapor deposition （CCVD） method. The as-produced carbonaceous product was characterized by thermal gravimetric analyzer （TGA）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and Raman spectroscopy. The experimental finding shows that CNTs were successfully produced from CNG while carbon nanofibers （CNFs） were formed as the side products. In addition, the catalytic activity and lifetime were found sustained and prolonged, as compared with using high purity methane as carbon source. The present study suggests an alternative route which can effectively produce CNTs and CNFs using low cost CNG.

关键词： compressed natural gas carbon nanotubes carbon nanofibers catalytic chemical vapor deposition

Enhancing the Robustness of Rib-Groove Filling and Strain Homogeneity in the Isothermal Forging of Titanium Alloy Multi-Rib Components

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CHINESE JOURNAL OF MECHANICAL ENGINEERING 2024年第1期37卷 1-28页

作者： Ding, Tong wei, Ke Hou, Yong Dong, Xianjuan Huang, Long lee, Myoung-Gyu Nanchang Hangkong Univ Sch Aeronaut Mfg Engn Nanchang 330063 Peoples R China Seoul Natl Univ Dept Mat Sci & Engn Seoul 08826 South Korea Seoul Natl Univ RIAM Seoul 08826 South Korea

Isothermal forging stands as an effective technology for the production of large-scale titanium alloy multi-rib components. However, challenges have persisted, including die underfilling and strain concentration due to the complex material flow and heterogeneous deformation within the forging die cavity. While approaches centered on optimized billet designs have mitigated these challenges, uncertainties in process parameters continue to introduce unacceptable variations in forming accuracy and stability. To tackle this issue, this study introduced a multi-objective robust optimization approach for billet design, accounting for the multi-rib eigenstructure and potential uncertainties. The approach includes finite element (FE) modeling for analyzing the die-filling and strain inhomogeneity within the multi-rib eigenstructure. Furthermore, it integrated image acquisition perception and feed back technologies (IAPF) for real-time monitoring of material flow and filling sequences within die rib-grooves, validating the accuracy of the FE modeling. By incorporating dimensional parameters of the billet and uncertainty factors, including friction, draft angle, forming temperature, speed, and deviations in billet and die, quantitative analyses on the rib-groove filling and strain inhomogeneity with fluctuation were conducted. Subsequently, a dual-response surface model was developed for statistical analysis of the cavity filling and strain homogeneity. Finally, the robust optimization was processed using a non-dominated sorting genetic algorithm II (NSGA-II) and validated using the IAPF technologies. The proposed approach enables robust design enhancements for rib-groove filling and strain homogeneity in titanium alloy multi-rib components.

关键词： Titanium alloy multi-rib components Die rib-groove filling Strain homogeneity Multi-objective robust optimization Real-time monitoring

Global and Kinetic MHD Simulation by the Gpic-MHD Code

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Plasma Science and Technology 2011年第5期13卷 528-534页

作者： Hiroshi NAITOU Yusuke YAMADA Kenji KAJIWARA wei-li lee Shinji TOKUDA Masatoshi YAGI Graduate School of Science and Engineering Yamaguchi University Princeton Plasma Physics Laboratory International Fusion Energy Research Center Research Institute for Applied Mechanics Kyushu University Japan Atomic Energy Agency

In order to implement large-scale and high-beta tokamak simulation, a new algorithm of the electromagnetic gyrokinetic PIC （particle-in-cell） code was proposed and installed on the Gpic-MHD code [Gyrokinetic PIC code for magnetohydrodynamic （MHD） simulation]. In the new algorithm, the vorticity equation and the generalized Ohm＇s law along the magnetic field are derived from the basic equations of the gyrokinetic Vlasov, Poisson, and Ampere system and are used to describe the spatio-temporal evolution of the field quantities of the electrostatic potential φ and the longitudinal component of the vector potential Az. The basic algorithm is equivalent to solving the reduced-MHD-type equations with kinetic corrections, in which MHD physics related to Alfven modes are well described. The estimation of perturbed electron pressure from particle dynamics is dominant, while the effects of other moments are negligible. Another advantage of the algorithm is that the longitudinal induced electric field, ETz = -δAz/δt, is explicitly estimated by the generalized Ohm＇s law and used in the equations of motion. Furthermore, the particle velocities along the magnetic field are used （vz-formulation） instead of generalized momentums （pz-formulation）, hence there is no problem of ＇cancellation＇, which would otherwise appear when Az is estimated from the Ampere＇s law in the pz-formulation. The successful simulation of the collisionless internal kink mode by the new Gpic-MHD with realistic values of the large-scale and high-beta tokamaks revealed the usefulness of the new algorithm.

关键词： tokamak gyrokinetic theory magnetohydrodynamics internal kink mode

Self-lubricating CrVN Coating Strengthened via Multilayering with VN

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Journal of Iron and Steel Research International 2014年第5期21卷 545-550页

作者： Yue-xiu QIU Bo LI Jyh-wei lee Dong-liang ZHAO Central Iron and Steel Research Institute Advanced Technology and Materials Co. Ltd. Department of Materials Engineering Ming Chi University of Technology Center for Thin Film Technologies and Applications Ming Chi University of Technology

To improve the mechanical properties of self-lubricating chromium vanadium nitride （CrVN） coatings, va- nadium nitride （VN） is combined with CrVN to form multilayered CrVN/VN coatings through an in-line magnetron sputtering system. The strengthening effect of the period thickness on the mechanical and tribological properties is studied. X-ray diffractometer, low-angle X-ray reflectivity, scanning electron microscopy, atomic force microscopy, electron probe micro-analyzer and X-ray photoelectron spectroscopy are employed to characterize the microstructures and chemical composition. Nanoindentation and ball-on-disc tribo-tester are used in characterization of the mechanical and tribological properties. The CrVN/VN multilayer coatings demonstrate good lubrication property with coefficient of friction down to 0.23. Multilayering with VN, the hardness of CrVN jumps to 27.6 GPa with period thickness of 6 nm, which has an improvement of 5.1 GPa compared with that of 22.5 GPa from rule-of-mixture.

关键词： CrVN/VN multilayered coating mechanical property self-luhricating magnetron sputtering

Clinical approach to incidental pancreatic cysts

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World Journal of Gastroenterology 2016年第3期22卷 1236-1245页

作者： Austin L chiang Linda S lee Division of Gastroenterology Hepatology and Endoscopy at Brigham and Women’s HospitalBostonMA 02115United States

The approach to incidentally noted pancreatic cysts is constantly evolving. While surgical resection is indicated for malignant or higher risk cysts, correctly identifying these highest risk pancreatic cystic lesions remains difficult. Using parameters including cyst size, presence of solid components, and pancreatic duct involvement, the 2012 International Association of Pancreatology(IAP) and the 2015 American Gastroenterological Association(AGA) guidelines have sought to identify the higher risk patients who would benefit from further evaluation using endoscopic ultrasound(EUS). Not only can EUS help further assess the presence of solid component and nodules, but also fine needle aspiration of cyst fluid aids in diagnosis by obtaining cellular, molecular, and genetic data. The impact of new endoscopic innovations with novel methods of direct visualization including confocal endomicroscopy require further validation. This review also highlights the differences between the 2012 IAP and 2015 AGA guidelines, which include the thresholds for sending patients for EUS and surgery and methods, interval, and duration of surveillance for unresected cysts.

关键词： Pancreatic cysts Intraductal papillarymucinous neoplasms Pancreatic cystic neoplasms Endoscopic ultrasound Mucinous cystic neoplasm Serous cystadenoma

A FINITE ELEMENT SHALLOW WATER CIRCULATION MODEL FOR TOLO HARBOUR, HONG KONG

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Chinese Journal of Oceanology and Limnology 1984年第1期2卷 20-33页

作者： Joseph Hun-wei lee Department Of Civil Ehgineering University of Hong Kong

Numerical solution of two-dimensional shallow water equations has been achieved by the finite element method. In this work, the governing equations were first converted into different equations suitable for explicit, forward marching, integration in the time domain. A second order Taylor’s series expansion was used for the continuity equation and an 'upwind' differencing was incorporated in the nonlinear convective terms in the momentum *** model was applied to Tolo Harbour in Hong Kong. Velocity vector plots and surface elevations obtained from the calculations are reasonably consistent with the expected tidal response of the systems.

关键词： HONG KONG A FINITE ELEMENT SHALLOW WATER CIRCULATION MODEL FOR TOLO HARBOUR 月卜 Bay

Prions:a threat to health security and the need for effective medical countermeasures

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Global Health Journal 2023年第1期7卷 43-48页

作者： Ying-chiang J.lee Department of Molecular Biology Princeton UniversityPrincetonNew Jersey 08544USA

Prions are infectious conformations of certain naturally occurring *** misfolded proteins can structurally alter healthy protein,creating misfolded copies that repeat the process and form protein aggregates that lead to neuronal cell *** years can pass from initial prion infection to clinical presentation of symptoms,onset of symptoms is typically followed by rapid neurological decline resulting in *** diseases have been characterized in animals ranging from sheep and cattle to cervids and humans,with notable cross-species infections such as the variant Creutzfeldt-Jakob ***,prions present a health risk with the potential to disrupt major food sources as well affect human health through animal to human and human to human transmission *** human to human prion transmission is rare and the immediate risks for a prion-facilitated pandemic are low,prions are a class of pathogens for which we are *** addition,prions,and prion disease-like approaches,have also been discussed in the context of biological weapons and toxins,adding another layer of complexity surrounding biosecurity and *** threats underscore the need for increased scrutiny and research on ***,pharmaceutical and nonpharmaceutical prion-specific interventions are *** advances in prion therapeutic development are also briefly highlighted,and a set of policy recommendations are given that aims to provide high level suggestions for the prevention and mitigation of prion diseases.

关键词： Prions Medical countermeasures Interventions Vaccines Biosecurity Policy

Secular trends of intrahepatic cholangiocarcinoma in a high endemic area:A population-based study

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World Journal of Gastroenterology 2022年第28期28卷 3695-3705页

作者： Chun-Ru Lin Yu-Kwang lee Chun-Ju chiang Ya-Wen Yang Hung-Chuen Chang San-Lin You School of Medicine College of MedicineFu Jen Catholic UniversityNew Taipei City 242008Taiwan Department of Surgery National Taiwan University HospitalTaipei 100229Taiwan Graduate Institute of Epidemiology and Preventive Medicine College of Public HealthNational Taiwan UniversityTaipei 10055Taiwan Division of Gastroenterology Department of Internal MedicineShin Kong Wu Ho-Su Memorial HospitalTaipei 111045Taiwan School of Medicine and Data Science Center Fu Jen Catholic UniversityNew Taipei City 242008Taiwan

BACKGROUND Intrahepatic cholangiocarcinoma(ICC)is one of the most aggressive ***,because of its scarcity there are limited population-based data available for investigations into its epidemiologic *** Taiwan,we have a national cancer registry database that can be used to evaluate the secular trends of *** To evaluate secular trends of ICC according to age,sex,and risk factors in *** In this population-based study,we used the national Taiwan Cancer Registry ***-standardized and relative percent changes in incidence rates were used to describe secular trends in incidence rates and sex ratios of ICC in *** The age-standardized ICC incidence rate among males increased from 1.51 per 100000 in 1993-1997 to 4.07 per 100000 in 2013-2017 and among female from 1.73 per 100000 to 2.95 per *** incidence in females tended to plateau after *** males,the ICC incidence increased as age *** the long-term incidence trend of ICC in females,the incidence of the four age groups(40-44,45-49,50-54 and 55-59 years)remained stable in different years;although,the incidence of the 60-64 group had a peak in 2003-2007,and the peak incidence of the 65-69 and 70-74 groups occurred in *** males,beginning at the age of 65,there were increases in the incidence of ICC for the period of 2003-2017 as compared with females in the period of *** Increased incidence of ICC occurred in Taiwan over the past two *** increased incidence has progressively shifted toward younger people for both males and females.

关键词： Intrahepatic cholangiocarcinoma Incidence Secular trend Sex ratio Risk factor

Lower serum folate is associated with development and invasiveness of gastric cancer

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World Journal of Gastroenterology 2014年第32期20卷 11313-11320页

作者： Teng-Yu lee En-Pei chiang Yin-Ting Shih Hsien-Yuan Lane Jaw-Town Lin Chun-Ying Wu Graduate Institute of Clinical Medical Science China Medical University Department of Medicine Chung Shan Medical University Division of Gastroenterology and Hepatology Taichung Veterans General Hospital Department of Food Science and Biotechnology National Chung Hsing University chiang Agricultural Biotechnology Center National Chung-Hsing University Department of Psychiatry China Medical University HospitalTaichung 404 Taiwan School of Medicine Fu Jen Catholic University Faculty of Medicine School of Medicine National Yang-Ming University Department of Life Sciences National Chung Hsing University Department of Public Health China Medical University

AIM: To evaluate the associations of serum folate levelwith development, invasiveness and patient survival of gastric cancer. METHODS: In this nested case-control study, patients with newly diagnosed gastric cancer undergoing gastrectomy were enrolled, and patients receiving chemotherapy prior to surgery, with other concurrent malignancy, or of the aboriginal and alien populations were excluded. In total, 155 gastric cancer patients and 149 healthy controls were enrolled for determination of serum folate levels and their correlation with gastric cancer. Using the median value of serum folate computed among the overall population as the cutoff value, the associations between serum folate and gastric cancer in all cases and different age and gender subgroups were analyzed by multivariate logistic regression analysis. In the patient cohort of gastric cancer, receiver-operating characteristic analyses were performed to calculate the best cutoff values of serum folate, and the associations between serum folate levels and clinicopathological features were further analyzed by multivariate regression analysis. Survival analyses were conducted using the Cox proportional hazards ***: The mean serum folate level was significantly lower in gastric cancer patients than that in controls(3.71 ± 0.30 ng/mL vs 8.00 ± 0.54 ng/mL, P < 0.01), and folate levels were consistently lower in gastric cancer patients regardless of age and gender(all P < 0.01). Using the median serum folate value as the cutoff value, low serum folate was significantly associated with gastric cancer risk in the whole population(OR = 19.77, 95%CI: 10.54-37.06, P < 0.001) and all strata(age < 60 years OR = 17.39, 95%CI: 7.28-41.54, age ≥ 60 years(OR = 21.67, 95%CI: 8.27-56.80), males(OR = 17.95, 95%CI: 7.93-40.62), and females(OR = 20.95, 95%CI: 7.66-57.31); all P < 0.001. In the patient cohort of gastric cancer, the respective cutoff values showed that low serum folate levels were significantly associa

关键词： Folic acid Folate Plasma Metastasis Invasion