共查询到20条相似文献,搜索用时 78 毫秒
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应用直流电沉积法在多孔氧化铝模板中制备了高度有序的CdS纳米线阵列,并由XRD、Raman、SEM、TEM和HRTEM等进行物理化学表征,结果表明,沉积在多孔氧化铝模板中的CdS呈六角结构,c轴沿孔长度方向定向生长,紫外吸收光谱研究表明,随着纳米线尺寸的减小,纳米线阵列的吸收边向短波长方向移动,荧光光谱测量显示,CdS纳米线阵列的荧光强度高于氧化铝模板,而且在可见光区的荧光特性与激发波长无关。 相似文献
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利用牛血清蛋白合成CdS纳米棒和网状纳米线 总被引:1,自引:0,他引:1
采用简单易控、对环境友好的矿化方法, 利用牛血清蛋白(BSA)做模板, 通过Cd2+与硫代乙酰胺(TAA)反应制备了形貌均一的CdS纳米棒和网状纳米线. 分别采用透射电子显微镜(TEM)、X射线能谱(EDS)、X射线衍射(XRD)、荧光(PL)发射谱和导电原子力显微镜(C-AFM)等方法对不同实验温度下制备的CdS样品的结构形貌、成分组成和光学性质及微区电子传输行为进行了表征. 结果表明: 在实验反应温度为20 ℃时, 得到的产物为单分散性好的CdS 纳米棒, 长度为250 nm, 直径为30 nm; 在50 ℃时, 得到网状CdS纳米线, 其长度为2-3 μm; CdS纳米棒和网状纳米线均为立方相闪锌矿结构. 荧光性质的测试表明, CdS纳米棒和网状纳米线具有优良的荧光性能, 电流-电压(I-V)特性的表征表明CdS纳米线具有很好的电导特性. 相似文献
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为了研究非配位型溶剂对聚酰胺-胺(PAMAM)树形分子的模板法制备CdS量子点的影响, 分别以水、甲醇及二者的混合物( ∶ =2∶1)为溶剂, 以4.5代PAMAM树形分子为模板制备了CdS量子点. 结果表明, 相同条件下, 以甲醇为溶剂时制备的CdS量子点为单晶, 平均直径2.7 nm, 尺寸分布窄, 发光强度高; 以水为溶剂制备的CdS量子点为多晶, 平均直径为5.7 nm, 尺寸分布宽, 发光强度低; 在甲醇与水的混合溶剂中制备的CdS量子点为单晶和多晶共存, 平均直径为4.1 nm, 尺寸分布及发光强度都居中. 这主要是由于树形分子的模板作用不同造成的. 树形分子在甲醇中能充分伸展, 起到内模板作用; 树形分子与水之间由双氢键作用而产生交联, 不利于Cd2+与树形分子内部基团的配位, 主要起到外模板作用; 在甲醇与水的混合溶剂中, 树形分子则同时起到了内模板和外模板作用. 相似文献
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模板法制备枝状Pt纳米线 总被引:8,自引:2,他引:8
一维纳米材料的制备是近年来纳米材料的研究热点. 利用具有纳米尺度的孔洞阵列模板沉积各种材料构筑纳米线的方法具有制备简便和成本较低等优点[1,2]. 常用的模板有多孔阳极氧化铝(AAO)、多孔硅和聚合物等, 其中AAO模板具有耐高温, 绝缘性好, 孔洞分布均匀, 孔径、孔深大小可控等特点, 是模板法研究的热点. 通过模板法电化学沉积制备各种金属纳米线已有很多报道[3~8], 本研究小组也曾报道了模板法电化学沉积Au等纳米线的制备及性质[9~12], 但用该方法制备的金属纳米线都为单一的线状结构. 组成当代大规模集成电路的基本器件一般具有3个或3个以上的电极. 单一的线状结构纳米线, 不能满足纳米电子学对纳米材料和纳米器件性能研究的需要. 在纳米器件的特性研究和探索中, 枝状或Y形纳米结的制备有重要的意义, 它是纳米器件从理论到实用化的必备条件. Sui等[13]用模板法成功制备了枝状碳纳米管, 但用AAO模板制备枝状金属纳米线的研究至今还未见报道. 本文通过控制铝片的阳极氧化条件, 先制备出具有分枝状孔洞结构的AAO模板, 再用电化学法沉积金属Pt, 实现了枝状Pt纳米线的可控生长. 这对其它金属枝状纳米线的制备以及进一步掺杂、构筑纳米原型器件等具有显著的实用价值. 相似文献
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This study constructed new curcumin-loaded lyotropic liquid crystals containing pharmaceutically accepted oil, and ethyl oleate (EtOL). Three liquid crystalline phases including lamellar, hexagonal, and cubic phases were identified by means of the polarized optical microscopy and rheology method. By analyzing the shear viscosity (η0.1), the viscosity of curcumin-liquid crystals is smaller than those without curcumin. Dynamic rheological results show that: Dissolved curcumin in EtOL can make the elastic modulus of hexagonal and cubic phase increase compared with that without curcumin, while the elastic modulus of lamellar phase decreases. Dissolved curcumin in Brij 97 can lead to the decreasing of the elastic modulus for cubic and lamellar phases, whereas it has little influence on hexagonal phase. When the curcumin is solubilized in both EtOL and Brij 97, the elastic modus of hexagonal phase increase, the elastic modus of lamellar and cubic phases decrease compared with that without curcumin. Furthermore, three temperature turning points were identified by the change in the slope of tanδ (G″/G′) for curcumin-hexagonal liquid crystal. These studies might be a help to study the storage of drug carrier and in vitro release properties of lyotropic liquid crystals containing curcumin. 相似文献
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Jun Hyup Lee Hye Jin Lee Seung Jun Lee Jisun Jang Seung Hoo Yoo Jae Young Jho 《Liquid crystals》2013,40(1):112-119
New conjugated polymeric columns with a hexagonal symmetry were prepared via topochemical polymerisation of star-shaped supramolecular liquid crystals formed by hydrogen bonding between a phloroglucinol core and pyridine derivatives containing a diacetylenic group in the alkyl chain. The mesomorphic properties of the supramolecular monomer and its photopolymerisation behaviour were investigated. The supramolecular liquid crystal exhibited a rectangular columnar mesophase. Photopolymerisation of supramolecular monomer along the column axis in the liquid crystalline state provided well-ordered conjugated polydiacetylenic columns with a two-dimensional hexagonal symmetry. Fourier transform infrared and ultraviolet–visible spectroscopy affirmed that conjugated polydiacetylenes were produced by 1,4-polymerisation of the supramolecular monomer along the column axis. X-ray diffraction analysis showed that a two-dimensional columnar order in the supramolecular monomer was maintained after photopolymerisation, and that the resulting polydiacetylene had a hexagonal array of conjugated columns. Our controlled methodology provides a new route to conjugated polymeric columns with highly ordered structures by self-assembly and polymerisation of star-shaped supramolecular liquid crystals. 相似文献
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Yan LI Qing Min ZHANG FuZhi HUANG Zhen Nan GU 《中国化学快报》2000,41(5):int1-470
OrderednanostrUcturessuchasnanopaticlesuperlattices,nanowirearrays,andmesoporousmolecularsievesareexpectedtOexhibitextraordinaryproperties'-'.ThereforethepreparationofsuchSthecturesisattractinggreatattCntionl'3'4.Thetemplatedirectedsynthesisisparticularlyimportantbecauseitcanperformagoodguidancetothewholereactionprocedure".Lyotropichexagonalliquidcrystalshavebeenwidelyusedasthesynthesistemplatesformesoporousmaterials6sincetheMobilgroupreportedtheirworkin19927'8.Recently,thehexagonalliquidcry… 相似文献
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Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporated single-crystals are limited to insulating crystals. Here, we examine crystals of two typical semiconductors, lead sulfide (PbS) and lead iodide (PbI2), grown from both silica gels and agarose gels. In all the four crystal-gel pairs, single-crystals of the cubic phase of PbS and the hexagonal phase of PbI2 were obtained according to the X-ray diffraction analysis. Dissolution of the gel-grown crystals exposed insoluble materials with the shape similar to the original crystals, indicative of gelincorporation inside the crystals. As such, this work creates a facile strategy to construct 3D heterostructures inside semiconducting single-crystals without destroying their long-range order. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(8):2194-2197
A new perylene bisimide (PBI) dye self‐assembles through hydrogen bonds and π–π interactions into J‐aggregates that in turn self‐organize into liquid‐crystalline (LC) columnar hexagonal domains. The PBI cores are organized with the transition dipole moments parallel to the columnar axis, which is an unprecedented structural organization in π‐conjugated columnar liquid crystals. Middle and wide‐angle X‐ray analyses reveal a helical structure consisting of three self‐assembled hydrogen‐bonded PBI strands that constitute a single column of the columnar hexagonal phase. This remarkable assembly mode for columnar liquid crystals may afford new anisotropic LC materials for applications in photonics. 相似文献
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不同晶型纳米CdS的合成及其光催化活性 总被引:1,自引:0,他引:1
以醋酸镉为镉源,硫脲为硫源,采用配合物热分解法,通过改变硫脲/醋酸镉的摩尔配比,合成了具有不同晶型的纳米CdS.当n(S)/n(Cd)=0.5—3时,合成的CdS相分别为立方相(n(S)/n(Cd)=0.5),立方相和六方相的混相(n(S)/n(Cd)=1.0~1.5),六方相(n(S)/n(Cd)≥2).通过XRD,TEM,UV—Vis光谱,IR光谱等对CdS的相组成,形貌,粒径,吸光性能,表面结构等进行了表征.光催化降解罗丹明B的活性结果表明,不同CdS相组成的活性顺序为立方相〉六方相〉混相(立方+六方),其中立方CdS相由于有较强的吸附作用、光吸收性能和较小的粒径(10~13nm),对罗丹明B具有最好的光催化降解活性. 相似文献
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Pena dos Santos E Tokumoto MS Surendran G Remita H Bourgaux C Dieudonné P Prouzet E Ramos L 《Langmuir : the ACS journal of surfaces and colloids》2005,21(10):4362-4369
We report the preparation of direct hexagonal liquid crystals, constituted of oil-swollen cylinders arranged on a triangular lattice in water. The volume ratio of oil over water, rho can be as large as 3.8. From the lattice parameter measured by small-angle X-ray scattering, we show that all the oil is indeed incorporated into the cylinders, thus allowing the diameter of the cylinders to be controlled over one decade range, provided that the ionic strength of the aqueous medium and rho are varied concomitantly. These hexagonal swollen liquid crystals (SLCs) have been first reported with sodium dodecyl sulfate as anionic surfactant, cyclohexane as solvent, 1-pentanol as co-surfactant, and sodium chloride as salt (Ramos, L.; Fabre, P. Langmuir 1997, 13, 13). The stability of these liquid crystals is investigated when the pH of the aqueous medium or the chemical nature of the components (salt and surfactant) is changed. We demonstrate that the range of stability is quite extended, rendering swollen hexagonal phases potentially useful for the fabrication of nanomaterials. As illustrations, we finally show that gelation of inorganic particles in the continuous aqueous medium of a SLC and polymerization within the oil-swollen cylinders of a SLC can be conducted without disrupting the hexagonal order of the system. 相似文献
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Jun Hyup Lee Sook Hee Hwang Seung Jun Lee Jae Young Jho Soo-Young Park 《Tetrahedron letters》2005,46(42):7143-7146
A series of discotic liquid crystals formed by simple hydrogen bonding between phloroglucinol core and alkoxystilbazole peripheral units was prepared. Nematic columnar and hexagonal columnar mesophases were observed depending on the length of alkyl chains around the aromatic core. 相似文献
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选取3种不同结构的苄醚型树枝状分子为分枝,以N-乙酰氨基葡萄糖为内核,合成出一类树枝化碳水化物;利用DSC、热台偏光显微镜、XRD和CD/UV光谱等手段研究该类化合物的液晶性,并命名为树状碳水化合物液晶。研究表明,连接有楔形树枝状单元的化合物形成手性柱状六方相或者向列相,连接有锥形树枝状单元的化合物未能如预期形成立方相,而仍然形成手性柱状六方相.超分子手性很可能源于树枝状单元与糖内核的协同自组装,使得树状分子沿着柱轴螺旋式堆砌;而糖环内核则对超分子柱的手性起调控作用,从而避免了外消旋的发生.该类化合物为研究碳水化合物诱导手性超分子聚集体提供了新的思路. 相似文献