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Effect of Fe_2O_3/SiO_2 ratio on maghemite-silica particulate nanocomposites

Journal of Central South University 2013年第11期20卷 2954-2959页

作者： ang bee chin YAACOB Iskandar Idris NURDIN Irwan Department of Mechanical University of Malaya Department of Manufacturing and Materials Engineering Kulliyyah of EngineeringInternational Islamic University Malaysia

Abstract： Maghemite-silica particulate nanocomposites were prepared by modified 2-step sol-gel process. Superparamagnetic maghemite nanoparticles were successfully produced using Massart＇s procedure. Nanocomposites consisting of synthesized maghemite nanoparticles and silica were produced by dispersing the as-synthesized maghemite nanoparticles into the silica particulate form. The system was then heated at 140 ℃for 3 d. A variety of mass ratios of Fe2O3/SiO2 was investigated. Moreover, no surfactant or other unnecessary precursor was involved. The nanocomposites were characterized using XRD, BET and AGM. The XRD diffraction patterns show the reflection corresponding to maghemite nanoparticles and a visible wide band at 20 from 20° to 35° which are the characteristics of the amorphous phase of the silica gel. The patterns also exhibit the presence of only maghemite and SiO2 amorphous phase, which indicates that there is no chemical reaction between the silica particulate gel and maghemite nanoparticles to form other compounds. The calculated crystallite size for encapsulated maghemite nanoparticles is smaller than the as-synthesized maghemite nanoparticles indicating the dissolution of the nanoparticles. Very high surface area is attained for the produced nanocomposites （360-390 m^2/g）. This enhances the sensitivity and the reactivity of the nanocomposites. The shapes of the magnetization curves for nanocomposites are very similar to the as-synthesized maghemite nanoparticles. Superparamagnetic behaviour is exhibited by all samples, indicating that the size of the maghemite nanoparticles is always within the nanometre range. The increase in iron content gives rise to a small particle growth.

关键词： maghemite nanoparticles nanocomposites sol-gel silica

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Applied bias photon-to-current conversion efficiency of ZnO enhanced by hybridization with reduced graphene oxide

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Journal of Energy Chemistry 2017年第2期26卷 302-308页

作者： Sharifah bee Abdul Hamid Swe Jyan Teh chin Wei Lai Siglinda Perathoner Gabriele Centi Nanotechnology and Catalysis Research Centre (NANOCAT) University of Malaya Department of Industrial Chemistry University of Messina

The role of reduced graphene oxide（rGO） in the enhancement of photo-conversion efficiency of ZnO films for photoelectrochemical（PEC） water-splitting applications was analyzed. ZnO and rGO-hybridized ZnO（rGO/ZnO） films were prepared via a two-step electrochemical deposition method followed by annealing at 300 °C under argon gas flow. The physical, optical and electrochemical properties of the films were characterized to identify the effect of rGO-hybridization on the applied bias photon-to-current efficiency（ABPE） of ZnO. Scanning electron microscopy and X-ray diffraction indicated the formation of verticallyaligned, wurtzite-phase ZnO nanorods. Diffuse-reflectance UV–visible spectroscopy indicated that rGO-hybridization was able to increase the light absorption range of the rGO/ZnO film. UPS analysis showed that hybridization with rGO increased the band gap of ZnO（3.56 eV） to 3.63 eV for rGO/ZnO sample,which may be attributed to the Burstein–Moss effect. Photoluminescence（PL） spectra disclosed that rGOhybridization suppressed electron-hole recombination due to crystal defects. Linear sweep voltammetry of the prepared thin films showed photocurrent density of 1.0 and 1.8 m A/cm;for ZnO and rGO/ZnO at+0.7 V, which corresponded to an ABPE of 0.55% and 0.95%, respectively. Thus, this report highlighted the multi-faceted role of rGO-hybridization in the enhancement of ZnO photo-conversion efficiency.

关键词： Zinc oxide Photoelectrochemical water-splitting Reduced graphene oxide Photo-conversion efficiency

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Novel layer-by-layer assembly of rGO-hybridised ZnO sandwich thin films for the improvement of photo-catalysed hydrogen production

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Journal of Energy Chemistry 2016年第2期25卷 334-342页

作者： Swe Jyan Teh chin Wei Lai Sharifah bee Abd.Hamid Nanotechnology & Catalysis Research Centre (NANOCAT) 3rd Floor Block A Institute of Postgraduate Studies (IPS) University of Malaya 50603 Kuala Lumpur Malaysia

Metal oxide semiconductor materials such as ZnO have tremendous potential as light absorbers for photocatalysed electrodes in the electrochemical reduction of water. Promoters such as rGO have been added to reduce the recombination losses of charge carriers and improve its photoelectrochemical activity. In this study, the effect of layer ordering on the charge transfer properties of rGO-hybridised ZnO sandwich thin films for the photo-catalysed electrochemical reduction of water was investigated. rGO-hybridised ZnO sandwich thin films were prepared via a facile electrode position technique using a layer-by-layer approach. The thin films were analysed using FESEM, XRD, Raman, PL, UV–vis, EIS and CV techniques to investigate its morphological, optical and electrochemical properties. The FESEM images show the formation of distinct layers of rGO and ZnO nanorods/flakes via the layer-by-layer method. XRD confirmed the wurtzite structure of ZnO. PL spectroscopy revealed a reduction of photoemission intensity in the visible region（580 nm） when rGO was incorporated into the ZnO thin film. Among the six thin films prepared, ZnO/rGO showed superior performance compared to the other thin films（0.964 m A/cm） due to the presence of graphene edges which participate as heterogenous electrocatalysts in the photocatalysed electrolysis of water. rGO also acts as electron acceptor, forming an n-p heterojunction which improves the activity of ZnO to oxidise water molecules to O2. EIS revealed that the application of rGO as back contact（rGO/ZnO, rGO/ZnO/rGO） reduces the charge transfer resistance of a semiconductor thin film. Alternatively, rGO as front contact（ZnO/rGO, rGO/ZnO/rGO） improves the photo-catalysed electrolysis of water through the participation of the rGO edges in the chemical activation of water. The findings from this study indicate that the layer ordering significantly affects the thin film＇s electrostatic properties and this understanding can be further advantageous fo

关键词： Heterojunction Layer-by-layer assembly ZnO thin film Photocatalysis

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高活性多壁碳纳米管/TiO_2纳米复合物光催化剂光催化降解活性黑5染料(英文)

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催化学报 2014年第12期35卷 2014-2019页

作者： Sharifah bee Abd Hamid Tong Ling Tan chin Wei Lai Emy Marlina Samsudin Nanotechnology & Catalysis Research Centre(NANOCAT) Institute of Graduate Studies Building University of Malaya 50603 Kuala Lumpur Malaysia

A nanocomposite UV-visible light-responsive multiwalled carbon nanotube (MWCNT)/titanium dioxide(TiO2) nanophotocatalyst was successfully synthesized by a modified sol-gel method using titanium isopropoxide and functionalized MWCNTs as the starting precursors. The photocatalytic activity of the TiO2 and the nanohybrid material was investigated through the photodegradation of Reactive Black 5 dye under ultraviolet light irradiation. X-ray diffraction analysis indicated that anatase phase was obtained for both the pure TiO2 and the MWCNT/TiO2 composite, while Raman spectroscopy confirmed the presence of MWCNTs in the composite. Field emission scanning elec-tron microscopy revealed that TiO2 nanoparticles with an individual diameter of about 10–20 nm were coated on the surface of the MWCNTs. The specific surface areas of the samples were found to be 80 and 181 m2/g for the pure TiO2 and MWCNT/TiO2, respectively. As a result, MWCNT/TiO2 showed better photocatalytic performance than pure TiO2 because the high surface area of MWCNTs enabled them to function as good electron acceptors for the retardation of electron-hole pair recombination.

关键词：多壁碳纳米管纳米复合材料 TiO2 光催化剂光降解活性黑二氧化钛纳米颗粒染料

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Protocol for a randomized controlled trial of electroacupuncture in the management of patients with axial spondyloarthritis in Singapore(E-AcuSpA)

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Rheumatology & Autoimmunity 2021年第2期1卷 104-114页

作者： Warren Fong Yu Heng Kwan Su-An Quek Ader Lim Chiah Yuen Wong Shin Yoong Chua Hui chin Tan Clara Eng Choy Tip Tan Bao Qiang Dong Youyi Huang Chuen Seng Tan bee Choo Tai Ting Hui Woon Jie Kie Phang Hwee Ling Koh Ying Ying Leung Julian Thumboo TrulsØstbye Department of Rheumatology and Immunology Singapore General HospitalSingaporeSingapore Duke-NUS Medical School SingaporeSingapore Department of Medicine Yong Loo Lin School of MedicineNational University of SingaporeSingaporeSingapore Internal Medicine Residency SingHealthSingaporeSingapore Programme in Health Services and Systems Research Duke-NUS Medical SchoolSingaporeSingapore Department of Pharmacy National University of SingaporeSingaporeSingapore Singapore Thong Chai Medical Institution SingaporeSingapore Acupuncture and Tuina College Liaoning University of Traditional Chinese MedicineShenyangLiaoningP.R.China Saw Swee Hock School of Public Health National University of SingaporeSingaporeSingapore

Background:Despite therapeutic advances,treatment of patients with axial spondyloarthritis(axSpA)continue to pose as a challenge as many do not respond well to conventional Western medications,such as nonsteroidal anti-inflammatory drugs(NSAIDs)and biologic diseasemodifying antirheumatic drugs(bDMARDs).Hence,acupuncture is a possible *** studies found electroacupuncture to be better than manual acupuncture,though no trials have been conducted in patients with *** clinical trial aims to evaluate the clinical efficacy,safety,and cost-effectiveness of electroacupuncture compared to manual acupuncture for patients with ***/Design:This randomized controlled trial will recruit 100 patients diagnosed with axSpA,who have active disease despite NSAIDs and *** patients will be randomized to receive either electroacupuncture or manual acupuncture in a 1:1 *** participants will receive standard rheumatologic care in addition to 20 acupuncture *** mean difference in Bath Ankylosing Spondylitis Disease Activity Index score between the 2 groups over 12 weeks will serve as the primary *** outcomes include improvements in other clinical,quality of life,and economic outcomes over 24 *** adverse events will be ***:Results from this trial may provide evidence regarding the clinical effectiveness,safety,and cost-effectiveness of electroacupuncture compared to manual acupuncture for patients with axSpA,and guide implementation into clinical *** of this trial include the lack of patient blinding,use of a repeated measures design,and possible variation in acupuncture technique amongst the various Traditional chinese Medicine practitioners.

关键词： axial spondyloarthritis complementary and alternative medicine electroacupuncture randomized controlled trial Traditional chinese Medicine

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论印度茶的崛起对晚清汉口茶叶市场的冲击

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武汉大学学报（人文科学版） 2001年第4期54卷 461-465页

作者：任放武汉大学人文科学学院湖北武汉430072

进入 1 9世纪 80年代后 ,由于印度茶的崛起 ,汉口茶市受到来自国际市场的猛烈冲击 ,茶农、茶商均苦不堪言。究其原因 ,在于印度茶园采取的是在英国资本控制下的资本主义大生产 ,其规模经济产生的高效率 ,实非传统手工、分散经营、资金... 详细信息

进入 1 9世纪 80年代后 ,由于印度茶的崛起 ,汉口茶市受到来自国际市场的猛烈冲击 ,茶农、茶商均苦不堪言。究其原因 ,在于印度茶园采取的是在英国资本控制下的资本主义大生产 ,其规模经济产生的高效率 ,实非传统手工、分散经营、资金匮乏、厘税苛繁、信息不灵的中国个体茶农可比。这意味着 ,中国茶的成本必然高于印度茶 ,在价格竞争上没有多少优势可言。晚清汉口茶叶市场虽然受到印度茶不同程度的挑战而时有剧烈波动 ,但整体贸易状况仍属繁盛。个中原因 ,概有如下三点 :一是俄国市场需求旺盛 ,常年刺激着砖茶的巨额出口。二是欧美市场仍看好华茶。三是国内需求大。

关键词：印度茶晚清汉口地区茶叶市场欧洲美国俄国

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CARSICK CARS ROAR BACK A GEAR SHIFT FOR MAINLAND INDIE GIANTS

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城市漫步（上海版、英文） 2014年第3期 52-52页

作者： ANDREW chin 不详

It's bee n n early five years since pion eeri ng in die-rock trio Carsick Cars ruled as kings of the Beijing under-ground *** lineup changes slowed their mercurial rise around 2009,singer/gui-tarist Zhang Shouwang Is ... 详细信息

关键词： band. CARS rule

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三十烷醇促进作物生长的效应

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华南农业大学学报 1981年第3期9卷 58-67页

作者：黄自然毛瑞昌李宝庆花廷钊钟九烈李艳芬黄金如卓铁汉陈裕成陆卫国华南农学院华南农学院华南农学院暨南大学广东省测试分析研究所广东省顺德县化学生物研究所

从蜂腊及蚕粪中提取高纯度的三十烷醇,是一种新的植物生长刺激剂,能促进水稻秧苗、白菜、黄瓜及马铃薯芽体组织培养的植株生长,增加鲜重及干物重。同时,促进水稻秧苗及黄瓜幼苗对氮、磷肥料的吸收。用^(32)P-同位素示踪表明,积累在黄瓜... 详细信息

从蜂腊及蚕粪中提取高纯度的三十烷醇,是一种新的植物生长刺激剂,能促进水稻秧苗、白菜、黄瓜及马铃薯芽体组织培养的植株生长,增加鲜重及干物重。同时,促进水稻秧苗及黄瓜幼苗对氮、磷肥料的吸收。用^(32)P-同位素示踪表明,积累在黄瓜苗根部的放射性强度较对照区增加12.36—16.19％。在盆栽条件下以淋灌10ppm三十烷醇稀释液的效果较好,马铃薯芽体组织培养基中含2ppm为佳。

关键词：三十烷醇马铃薯 ppm 植物生长促进剂土豆茄属放射性强度放射性活度水稻秧苗作物生长

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