Synthesis and Characterization of Co-Doped Brookite Titania Photocatalysts with High Photocatalytic Activity     

Xin Tan  Xianshou Huang  Yunling Zou  Tao Yu  Yang Zhao  Xiang Huang 《天津大学学报(英文版)》2018,(2)

Transition metal-doping could effectively extend the light response range of TiO _2 photocatalysts from the ultraviolet(UV)to the visible region.Co-doped brookite titanium dioxide(Co–TiO_2)photocatalysts were synthesized via the hydrothermal method with titanium tetrachloride as the raw material and cobalt chloride hexahydrate as the dopant.The prepared Co–TiO_2 photocatalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS)and UV–Vis diffuse reflectance spectroscopy(UV–Vis DRS).The photocatalytic activities of Co–TiO _2 photocatalysts were evaluated by photocatalytic degradation of isopropanol alcohol(IPA),a typical volatile organic compound(VOC),under visible light.The influences ofdifferent Co doping rates,initial concentrations of IPA gas and the amounts of photocatalyst addition were also studied.At the same time,the enhancement mechanism ofcobalt ions as a trap for photogenerated holes was discussed.Thus,we found the optimum doping rate,initial concentration of IPA gas and amount of photocatalyst to add.The results show that the mesoporous Co–TiO _2 photocatalysts possess smaller size particles,larger specific surface area,lower forbidden bandgap energy(Eg)and better photocatalytic activity than pure brookite TiO _2.When the doping of Co was 7% by mass,the initial concentration ofIPA gas was 1.0×10~(-6 )mol/L and the addition of Co–TiO_2 photocatalysts was 50 mg,the best photocatalytic activity was achieved.Furthermore,the degradation rate ofIPA was up to 91%,which shows great potential for waste water treatment.  相似文献   

远程课程的质量保证与效果评价   总被引：13，自引：5，他引：13  

谭尚渭 《中国远程教育(综合版)》2002,(12):6-8

香港公开大学是一所开放和远程大学,非常注意资讯技术在教育中的有效运用。然而,大学的理念是:资讯技术能使远程教学的传递多元化,但远程教育的成功依赖于优质的课程和良好的学生学习支援。本文着重介绍香港公开大学远程课程的开发、质量保证以及效果评价。作者认为,无论是采用印刷媒体,还是电子教学,都需要依据有关的教学和学习理论,根据学生的学习方式,进行良好的教材设计和编写。然而,现代技术的运用有助于大中华的远程教育学者们进行合作和联合,共建和共享优质课程,从而服务于人类与社会。  相似文献   

装饰中的秩序感     

An Limei) Hou Yongrui ) Tan Haonan) 《石家庄铁路工程职业技术学院学报》2006,(1)

无论变化与统一、对比与调和、节奏与韵律、放射与回旋,都表现了一种秩序性,秩序是装饰之美的尺度。秩序是装饰之美的内在尺度。秩序代表着和谐,代表着变化以及变化后的统一,它始终与稳定和永恒性相联系。  相似文献   

苏轼谐谑诗探源     

和谈 《新疆教育学院学报》2006,22(1):98-101

诗本正体,自古皆以“温柔敦厚”为准绳和规矩。然东坡诗中有大量的戏谑调侃之作。诗作如此谐谑,颇值人们注意和研究。在界定了谐谑诗的内涵外延并探明谐谑诗源流后,本文着重分析苏轼谐谑诗之源:性格和经历是影响苏轼创作谐谑诗重要的内、外因素,对前贤的学习和继承是影响其创作的重要条件,而创作思想则影响了他谐谑诗创作的内容、技巧、风格等。  相似文献   

建构主义学习理论的认识论特征分析   总被引：1，自引：0，他引：1  

谭敬德  陈清 《现代教育技术》2005,15(6):10-13

文章从激进建构主义和温和建构主义维度分析建构主义在认识论上的特征,接着分析了几种主要学习理论的认识论特点,指出从认识论角度看,建构主义是一种既不同于主观主义也不同于客观主义的第三种认识论,是一种介于主观主义和客观主义之间的认识论。最后分析建构主义学习理论作为教育技术学理论基础时应注意的问题。  相似文献   

Characterization and photocatalytic activity of mixed nanocrystalline TiO<Subscript>2</Subscript> powders prepared by xerogel-hydrothermal method in different acid solutions     

刘翠萍  于涛  谭欣 《天津大学学报(英文版)》2016,22(5):473-479

TiO₂ nanoparticles(NPs)were prepared via the hydrothermal route of TiO₂ xerogel in nitric acid, hydrochloric acid and acetic acid. The physico-chemical properties of the powders were characterized by X-ray diffraction(XRD)and N₂ adsorption desorption techniques. The effects of the different acids on the structure(crystal phase)and texture(primary particle size and porosity)of the TiO₂ powders were explored. Results indicated that acetic acid facilitated the formation and stability of pure anatase phase. On the other hand, nitric acid and hydrochloric acid led to the transformation from anatase to rutile. The catalyst synthesized via the hydrothermal route of TiO₂ xerogel in the low concentration hydrochloric acid solution(Ti-HCl-0.15)had the highest photocatalytic activity than the catalysts obtained in the other two acid solutions. The effects of the different acids were discussed in terms of acid strength, chelating effect and the thermal stability of the adsorbed acidic anions.  相似文献   

经济管理类课程开展案例教学的探索     

谭琳 《职业技术教育》2006,27(29):56-58

在职业院校经济管理类课程中开展案例教学,可以形象地传授管理知识,将学习者置于复杂的经济管理现实环境中,更好地理解经济管理理论和知识.在具体的案例教学中,要提出一个没有明显正确答案的问题,引起学习者的争论,并运用案例中的信息思考问题.教师在案例教学中作为组织者、引导者应做到使讨论井然有序,协助学生理清思路,监督学生学习进展情况.  相似文献   

某些4-氨基-1-氮杂-1,3-丁二烯(Ⅱ)新化合物及其3-氯(Ⅲ)和3-溴(Ⅳ)衍生物的合成     

谭成权  Pedro J.Campos  Miguel A.Rodriguez 《大连大学学报》1996,(2)

用希夫碱(Ⅰ)在无水三氯化铝(AlCl_3)或二异丙胺锂(LDA)与氯化锌乙醚溶液(ZnCl_2·OEt_2)存在下加成于腈类化合物,制备了一些新的4-氨基-1-氮杂-1,3-丁二烯(Ⅱ)。用N-氯琥珀酰亚胺(NCS)和N-溴琥珀酰亚胺(NBS)与带有3-位烯胺氢原子的化合物Ⅱ合成了3-氯(Ⅲ)和3-溴(Ⅳ)衍生物。全部化合物Ⅱ、Ⅲ和Ⅳ都经MS、~1H和~(13)C NMR定性,文中给出了其MS、~1H和~(13)C NMR数据。  相似文献   

Practicum teachers’ use of mobile technology as measured by the technology acceptance model     

Zachary Walker  Hui Han Kho  Desiree Tan  Nathaniel Lim 《Asia Pacific Journal of Education》2020,40(2):230-246

ABSTRACT

This study utilized the Technology Acceptance Model (TAM) to examine practicum teachers’ current use of mobile technology and their intentions of use in the future. A survey was conducted to better understand the relationship between practicum teachers and their potential assimilation of technology into classroom practice. The survey questionnaire was administered to 100 undergraduate students at [institute withheld], [country withheld]’s teacher preparatory university. The following four key constructs of the TAM were assessed: perceived ease of use (PEU), perceived usefulness (PU), subjective norm (SN), and behavioural intention to use (BIU). The impact of practicum teachers’ gender and academic subjects on their acceptance of technology were also investigated. The present study found strong links between PEU and PU. While practicum teachers perceived mobile technology as being useful and intended to use it in their classrooms, BIU was not significantly impacted by PEU, PU, or SN. The data also suggested that gender did not affect BIU while practicum teachers’ academic subjects might be an indicator of their future intentions to use mobile technology. With these findings, recommendations are made to further improve the integration of mobile technology in classroom practice.  相似文献   

服务语言的使用原则   总被引：1，自引：0，他引：1  

谭永康 《重庆广播电视大学学报》2005,17(1):43-45

作为工作用语的服务语言,在客我交往活动中,必须表现出明确的服务目的性,因而有别于人们日常的交际语言.从业人员使用服务语言,符合规范性,保持文明礼貌,并与语境相适应,必须进行严格的自我调整和控制.  相似文献