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1.
用V_2O_5和草酸作为初始原料,在水热条件下合成了VO_2(A)纳米杆.通过改变初始的V_2O_5与草酸摩尔比以及反应时间制备纯相VO_2(A).样品的元素组成、微结构及光学性能分别被X射线光电子能谱(XPS)、X射线衍射(XRD)、扫描电镜(SEM)、差示扫描量热法(DSC)和傅里叶变换红外光谱(FT-IR)表征.实验结果表明合成VO_2(A)的最佳条件为:反应温度230℃、保温24h以及V_2O_5对草酸摩尔比为1∶1.5.结合XRD数据与SEM图像,提出一个转变、自组装和重结晶过程解释了VO_2(A)纳米棒的形成过程.  相似文献   

2.
在VO2-草酸体系中,利用一步水热合成法制备结晶良好的VO2(A)纳米杆.成品的结构和尺寸分别通过X射线衍射(XRD)、扫描电镜(SEM)和透射电子显微镜(TEM)表征.差示扫描量热(DSC)曲线显示在加热过程中VO2的相转变温度为167.8 ℃.变温X射线衍射(XRD)图谱显示加热时VO2(A)在160~180 ℃发生相变.温度升高到450 K时,磁化率突然增加.使用4探针法测量VO2(A)样品的电阻率,滞后现象显示VO2(A)的相变为1级相变.根据阿仑尼乌斯曲线,得出低温VO2(AL)和高温VO2(AH)的活化能分别为0.39 eV和0.37 eV.变温红外光谱显示VO2(A)纳米杆在红外区域具有良好的光学转换特性,此特性与VO2(A)的可逆结构转变有关.研究结果表明VO2 (A)纳米材料可应用于红外开关装置.  相似文献   

3.
以V2O5和草酸为原料,水热合成了VO2(B)带状结构.采用XRD,SEM,TEM和HRTEM等技术对不同水热条件下所得产物进行了表征,根据不同反应条件下产物的结构和形貌推断了VO2(B)带状结构的生长机理.结果表明:在水热反应过程中,V2O5首先和草酸反应生成V6O13,随着水热反应时间的延长,V6O13继续和草酸反应生成VO2(B),且最初生成的VO2(B)为杂乱无章的片状堆积结构,随着水热反应时间的延长,片状结构逐渐转化为长度约为1μm,宽度约为100~200 nm的带状结构,其晶格条纹间距约为0.51 nm.  相似文献   

4.
以V2O5和草酸的黄褐色悬浊液为前驱物水热合成VO2(B)纳米带,采用XRD技术研究水热条件对VO2(B)纳米带结构的影响。结果表明,在水热温度为180~190℃、水热时间为20~24h时,可以制备结晶良好的VO2(B)纳米带;随着水热温度的升高,VO2(B)纳米带的平均晶粒尺寸逐渐增大,晶格畸变度逐渐减小,且产物的择优生长趋势逐渐明显;水热反应初期,VO2(B)纳米带的平均晶粒尺寸增长较快,随着水热时间的延长,VO2(B)纳米带的晶粒生长趋于平衡,晶格畸变度逐渐减小并趋于平缓,且产物逐渐形成了一定的结晶取向。  相似文献   

5.
以LiOH·H2O和V2O5为原料,采用溶胶-凝胶法制备层状锂离子电池正极材料LiV3O8.经X射线衍射(XRD)和扫描电子显微镜(SEM)分析表征其结构形貌,充放电测试其电化学性能,比较研究柠檬酸、草酸、酒石酸和双氧水4种配体,及金属元素与配体的物质的量比和煅烧温度等对材料性能的影响.结果表明:溶胶-凝胶法可制得晶形...  相似文献   

6.
利用模板法合成介孔纳米γ-Al2O3,用透射电镜(TEM)、X射线衍射(XRD)、比表面测定(BET)等手段对所得的介孔纳米γ-Al2O3进行了表征.考察了介孔纳米γ-Al2O3在静态条件下对硫酸根离子的吸附性能.探讨了溶液的初始浓度、pH值、时间和温度对吸附性能的影响,结果表明:介孔纳米γ-Al2O3对硫酸根离子有较好的吸附性能,其吸附行为符合Freundlich等温式.  相似文献   

7.
利用模板法合成介孔纳米γ=Al2O3,,用透射电镜(TEM)、X射线衍射(XRD)、比表面测定(BET)等手段对所得的介孔纳米γ-Al2O3进行了表征.考察了介孔纳米γ-Al2O3在静态条件下对硫酸根离子的吸附性能.探讨了溶液的初始浓度、pH值、时间和温度对吸附性能的影响,结果表明:介孔纳米γ-Al2O3对硫酸根离子有较好的吸附性能,其吸附行为符合Freundlich等温式.  相似文献   

8.
在VO_2-草酸体系中,利用一步水热合成法制备结晶良好的VO_2(A)纳米杆.成品的结构和尺寸分别通过X射线衍射(XRD)、扫描电镜(SEM)和透射电子显微镜(TEM)表征.差示扫描量热(DSC)曲线显示在加热过程中VO_2的相转变温度为167.8℃.变温X射线衍射(XRD)图谱显示加热时VO_2(A)在160~180℃发生相变.温度升高到450K时,磁化率突然增加.使用4探针法测量VO_2(A)样品的电阻率,滞后现象显示VO_2(A)的相变为1级相变.根据阿仑尼乌斯曲线,得出低温VO_2(AL)和高温VO_2(AH)的活化能分别为0.39eV和0.37eV.变温红外光谱显示VO_2(A)纳米杆在红外区域具有良好的光学转换特性,此特性与VO_2(A)的可逆结构转变有关.研究结果表明VO_2(A)纳米材料可应用于红外开关装置.  相似文献   

9.
在水泥生料中分别掺入质量分数为0.5%、1.0%、1.5%、2.0%和3.0%的V2O5和Cr2O3,煅烧至1550℃,研究V5+和Cr3+掺杂对C2S多晶型形成过程的影响.经化学分析、X射线衍射(XRD)、扫描电镜(SEM)和红外光谱(ET -IR)等方法分析,结果表明:当V2O5和Cr2O3质量分数分别大于0.5%...  相似文献   

10.
水热法制备CdSe纳米晶   总被引:1,自引:0,他引:1  
用合成的Na2SeSO3和Cd(NO3)2.4H2O在水溶液中180℃下反应12h,合成了直径为100 nm的CdSe纳米球,利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对其结构进行了表征,并探讨了其生长机理.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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