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surface characterization of polyimide and polyethylene terephthalate membranes toward plasma and UV treatments

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Progress in Natural science:Materials International 2022年第3期32卷 314-327页

作者： Thi sinh Vo Tran Thi Bich chau Vo school of Mechanical Engineering Sungkyunkwan University Department of Industrial Management Can Tho University

This study is to bring an overview on various methods regarding the surface treatment performed on different polymeric membranes in relation to a deference between the treatment mechanism and their chemical ***, plasma and UV surface treatments(PsT and UsT) were utilized to treat the surfaces of two commercial membranes, i.e., aromatic polyimide and polyethylene terephthalate for various durations using a discharge electrode and an UV LED curing system, respectively. Based on the effects of PsT and UsT processes on the surface of these membranes, their surface properties have been characterized to surface morphology and hydrophilicity(or wettability), at same time the changes have probably occurred on their surface during the PsT and UsT processes. As a result, their hydrophilic behavior was significantly enhanced after conducting these treatment processes based on the investigation of water contact angle. Moreover, Fourier-transform infrared and Raman spectroscopy manifested the changes in the chemical bonds, interactions and orientations of molecules, which confirmed the apparition and insertion of polar functional groups after the surface treatments, and accordingly,their wettability was enhanced significantly. Also, optical microscopy images showed direct impactions on their surface and the evidence of slight surface aging/damage during the treatment processes based on the presentation of the strange streaks on the treated surfaces. In particular, the peel forces exhibited an increase comparing to the initial membranes, which is characteristically for enhancing their adhesion behavior. Hence, these results are needful for improving the surface properties of a material, and obtaining better adhesion behavior on the membrane-like materials and recycling polymer materials.

关键词： Plasma treatment UV treatment Polymeric membrane Aromatic polyimide Polyethylene terephthalate

Newmark design spectra considering earthquake magnitudes and site categories

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Earthquake Engineering and Engineering Vibration 2016年第3期15卷 519-535页

作者： Bo Li Wei-chau Xie M.D.Pandey Department of Civil and Environmental Engineering University of Waterloo

Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies and larger amplitudes at low frequencies in comparison with spectra developed by statistical methods. To resolve this problem, this study considers three suites of ground motions recorded at three types of sites. Using these ground motions, influences of the shear-wave velocity, earthquake magnitudes, source-to-site distances on the ratios of ground motion parameters are studied, and spectrum amplification factors are statistically calculated. spectral bounds for combinations of three site categories and two cases of earthquake magnitudes are estimated. site design spectrum coefficients for the three site categories considering earthquake magnitudes are established. The problems of Newmark design spectra could be resolved by using the site design spectrum coefficients to modify the spectral values of Newmark design spectra in the acceleration sensitive, velocity sensitive, and displacement sensitive regions.

关键词： Newmark design spectrum site design spectrum coefficients site conditions

Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.W.Wi y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

We investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths

Energy-efficient spectrum-aware clustering for cognitive radio sensor networks

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Chinese science Bulletin 2012年第28期57卷 3731-3739页

作者： ZHANG HuaZi ZHANG Zhaoyang yUEN chau Department of Information science and Electronic Engineering Zhejiang UniversityHangzhou 310027China Zhejiang Provincial Key Laboratory of Information Network Technology Hangzhou 310027China singapore University of Technology and Design Singapore

As a smart combination of cognitive radio networks and wireless sensor networks,recently introduced cognitive radio sensor network(CRsN) poses new challenges to the design of topology maintenance techniques for dynamic primary-user *** paper aims to provide a solution to the energy-efficient spectrum-aware CRsN clustering ***,we design the clustered structure,establish a network-wide energy consumption model and determine the optimal number of *** then employ the ideas from constrained clustering and propose both a centralized spectrum-aware clustering algorithm and a distributed spectrum-aware clustering(DsAC) *** extensive simulations,we demonstrate that DsAC can effectively form clusters under a dynamic spectrum-aware ***,DsAC exhibits preferable scalability and stability with its low complexity and quick convergence under dynamic spectrum variation.

关键词：无线传感器网络认知无线电频谱感知集群节能高效聚类问题无线电网络

HER2 inhibition in gastro-oesophageal cancer:A review drawing on lessons learned from breast cancer

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World Journal of Gastrointestinal Oncology 2018年第7期10卷 159-171页

作者： Hazel Lote Nicola Valeri Ian chau Centre for Molecular Pathology Institute of Cancer Research Department of Medicine Royal Marsden Hospital

Human epidermal growth factor receptor 2(HER2)-inhibition is an important therapeutic strategy in HER2-amplified gastro-oesophageal cancer(GOC).A significant proportion of GOC patients display HER2 amplification,yet HER2 inhibition in these patients has not displayed the success seen in HER2 amplified breast *** of the current evidence surrounding HER2 has been obtained from studies in breast cancer,and we are only recently beginning to improve our understanding of HER2-amplified *** there are numerous licensed HER2 inhibitors in breast cancer,trastuzumab remains the only licensed HER2 inhibitor for HER2-amplified *** trials investigating lapatinib,trastuzumab emtansine,pertuzumab and MM-111 in GOC have demonstrated disappointing results and have not yet changed the treatment *** deruxtecan may hold promise and is currently being investigated in phase Ⅱ ***2 amplified GOC differs from breast cancer due to inherent differences in the HER2 amino-truncation and mutation rate,loss of HER2 expression,alterations in HER2 signalling pathways and differences in insulin-like growth factor-1 receptor and MET *** alterations involving different micro RNA profiles in GOC as compared to breast cancer and intrinsic differences in the immune environment are likely to play a *** key to effective treatment of HER2 amplified GOC lies in understanding these mechanisms and tailoring HER2 inhibition for GOC patients in order to improve clinical outcomes.

关键词： Human epidermal growth factor receptor 2 Gastro-oesophageal cancer Trastuzumab Resistance Biomarkers Breast cancer

Effects of hedgerows on sediment erosion in Three Gorges Dam Area, China

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International Journal of sediment Research 2008年第2期23卷 119-129页

作者： sai-Leung NG Kwai-Cheong chau Department of Geography and Resource Management the Chinese University of Hong KongHong KongChinaProf

The Three Gorges Dam Area refers to the river section from Chongqing to yichang on the yangtze River,which has a drainage area of 75,098 km2,and involves 19 cities and *** hedgerows have been used in this area to control soil erosion and to improve hillslope stability in the catchment of this river *** experimental hedgerow plots were established in 1994 in order to study the effects of hedgerows on erosion *** the period of 1994-1997,runoff and soil loss data were collected on these test plots,including the chemical and physical properties of soil and related topographical *** results indicate that:(1) after 4 years of cultivation and crop planting,soil fertility increased dramatically in the hedgerow *** organic matter,total nitrogen,and total phosphorus contents in the hedgerow plots were 5-9 times higher than that in the control *** each of the hedgerow plots,soil structure became more stable,the quantity of granules larger than 0.02 mm increased and those finer than 0.02 mm decreased;(2) All hedgerow plots showed a major effect on reducing soil loss and surface runoff;(3) Overland flow velocity along the upper portion of the hedgerow plots was greatly reduced due to hedgerow resistance,which explains the significant decrease in soil losses in hedgerow plots,despite the fact that the hedgerow plots and the control plots had the same total runoff.

关键词： Hedgerow Erosion Runoff soil properties Three Gorges Dam Project

A hyperbolic Lindstedt-Poincare method for homoclinic motion of a kind of strongly nonlinear autonomous oscillators

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Acta Mechanica sinica 2009年第5期25卷 721-729页

作者： y.y.Chen s.H.Chen K.y.sze Department of Applied Mechanics and Engineering sun yat-sen University Department of Mechanical Engineering The University of Hong Kong Department of Applied Mechanics and Engineering Sun Yat-sen University

A hyperbolic Lindstedt-Poincare method is presented to determine the homoclinic solutions of a kind of nonlinear oscillators, in which critical value of the homoclinic bifurcation parameter can be determined. The generalized Lienard oscillator is studied in detail, and the present method＇s predictions are compared with those of Runge-Kutta method to illustrate its accuracy.

关键词： Lindstedt-Poincare method Hyperbolic function Nonlinear autonomous oscillator - Homoclinic orbit

Element diffusion ability in metasomatic agents and its effect on chemical characteristics of metasomatized peridotites

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science China Earth sciences 2006年第9期49卷 926-937页

作者： y s O’Reilly GEMOC ARC National Key Centre Department of Earth and Planetary Sciences Macquarie University Sydney N.S.W. 2109 Australia

Detailed in situ LM-ICPMs researches on the composite xenoliths from yingfengling volcano of Leizhou Peninsula, south China, indicate that most incompatible trace elements of clino- pyroxenes in composite xenoliths decrease spatially from pyroxenites to distal lherzolites, and com- patible elements and HREE increase steeply. The increasing and decreasing rate is distinct for dif- ferent trace elements, which give rise to element chromatographic fractionation within metasomatized lherzolites. The element chromatographic fractionation result actually from the difference in element diffusive rate in melts or fluids percolating through wall-rock lherzolites. Based on element variation profiles in composite xenoliths this study indicates that sr, Nb, La and Ce have the highest diffusive mobility, MREE-HREE are moderate, and Zr, Hf, Ti, Ga and sc are very low in most cases. Higher diffusive rates of LREE than HREE would enlarge the REE fractionation of metasomatized peridotites, and lower diffusive rate of Zr, Hf and Ti relative to neighbor REEs with similar incompatibility would cause the relative depletion of these elements in metasomatized peridotites. Trace elements com- monly have a higher diffusive rate in fluid-rich infiltrating melt, which will weaken element chroma- tographic fractionation during the metasomatism. The range of mantle metasomatism caused by sili- cate melt intrusion is very limited, generally within tens of centimeters wide. The width of metasoma- tized wall-rock peridotites near the pyroxenite or horblendite veins was strictly controlled by both melt volume and chemical characteristics.

关键词： composite xenolith, metasomatism, chromatographic fractionation, diffusive rate, Leizhou Peninsula.

LINEARIZATION OF A NONLINEAR PERIODIC BOUNDARy CONDITION RELATED TO CORROsION MODELING

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Journal of Computational Mathematics 2007年第6期25卷 645-660页

作者： y. s. Bhat s. Moskow Institute for Mathematics and its Applications Univ. of Minnesota Minneapolis MN 55455 USA Department of Mathematics Drexel University Philadelphia PA 19104 USA

We study galvanic currents on a heterogeneous surface. In electrochemistry, the oxidation-reduction reaction producing the current is commonly modeled by a nonlinear elliptic boundary value problem. The boundary condition is of exponential type with periodically varying parameters. We construct an approximation by first homogenizing the problem, and then linearizing about the homogenized solution. This approximation is far more accurate than both previous approximations or direct linearization. We establish convergence estimates for both the two and three-dimensional case and provide two-dimensional numerical experiments.

关键词： Galvanic corrosion Homogenization Nonlinear elliptic boundary value problem Butler-Volmer boundary condition Robin boundary condition.