Dissertation > Excellent graduate degree dissertation topics show

Different morphology of nano - materials synthesis and optical , magnetic properties of

Author: WangGuangLi
Tutor: TangBo
School: Shandong Normal University
Course: Analytical Chemistry
Keywords: hydrothermal technology morphology control formation mechanism preparation characterization
CLC: TB383.1
Type: Master's thesis
Year: 2006
Downloads: 205
Quote: 0
Read: Download Dissertation

Abstract


Nanomaterials have become the focus of considerable interest because they canshow novel properties which are superior to or different from the corresponding bulkmaterials. Research shows that the properties of nanomaterials depend on theirmorphology. So the development of reproducible and reliable methods to produceuniform and stable nanomaterials with different morphology is of significance forexploring their novel physical and chemical properties as well as the potentialapplications. In this thesis, the hydrothermal technique was developed. A series ofnanomaterials with different morphology were synthesized with simple new methods.Compared to conventional organic dyes, sufficiently passivated QDs appear to beless susceptible to photobleaching with much narrower emission spectra, which havebeen successfully used as fluorescent probes in imaging of biological samples andcells. Nanostructured semiconductor materials with unique optical properties havegenerated great research interest in the past two decades. Most attention has been paidto quantum dots (QDs). Owing to the quite different quantum confinement energies,one-dimensional (1D) nanostructures present some novel optical properties differentfrom zero-dimensional nanostructures. However, exploration of water soluble 1Dsemiconductor materials as fluorescent sensors for biological samples and cellsremains at a very early stage. This is partially due to the difficulties with thedispersion of these nanomaterials in water.There are five charpters in this dissertation:Charpter one: A review on the property and application of nanomaterials withdifferent morphology. The hydrothermal technology was described . Additionally, thesynthesis, property and application of one-dimensional semiconductor nanomaterialswere briefly discussed.Charpter two: Ddandelion-like three-dimensional β-MnO2 microstructures weresynthesized through the direct hydrothermal reaction between manganese nitrate andhydrogen peroxide. The formation mechanism of the dandelion-like microstructureswas investigated and discussed based on the experimental results. Magneticmeasurements showed that the Néel temperature of the as-obtained product was 100K,which was about 6K higher than that of the corresponding bulk β-MnO2 crystals.Charpter three: β-MnO2 single crystalline nanorods were synthesized employinga simple in-situ redox precipitation hydrothermal process. This was a good method forthe selected-control synthesis of β-MnO2. The effects of various experimentalconditions on the morphology of the products were investigated. The formationmechanism of the nanorods was investigated and discussed based on the experimentalresults. The magnetic measurement of the nanorods indicated that the Néel magnetictransition temperature was about 4K higher than that of the bulk β-MnO2 crystal.Charpter four: α-FeOOH nanorods were synthesized via a low-temperaturehydrothermal method. Transmission electron microscopy images taken at differenthydrothermal reaction times showed that the formation of the nanorods follows the“rolling-broken-growth” process. After calcined the as-synthesized α-FeOOH at250oC for 2h, α-Fe2O3 nanorods could be obtained. Very interestingly, the as-obtainedα-Fe2O3 nanorods exhibited interesting magnetic properties which were anomalouscompared to the corresponding bulk α-Fe2O3 material.Charpter five: The synthesis of water-soluble one-dimensional CdSenanomaterials was tentatively explored by using L-cystein and polyphosphate sodiumas capping agents.

Related Dissertations

  1. Phosphorus pentoxide composite ammoniated condensing agent preparation of ammonium polyphosphate,TQ314.248
  2. Studies on Synthesis, Characterization and Properties of Fe-V Co-doped TiO2 Catalyst,O614.411
  3. Preparation and Properties of Highly Active Dietary Fiber and Carboxymethylcellulose from Gracilaria Residue,TS254.9
  4. Improvement of Preparation Technology for Chitin and Chitosan from By-product of Litopenaeus Vannamei,TS254.9
  5. Cloning and Expression of Xylanase Gene from Thermobifida Halotolerans YIM 90462~T,Q78
  6. The Research of the Sludge Characteristics in the Cephalosporin Intermediate Pharmaceutical Wastewater by the Treatment of the NMBR,X787
  7. Synthesis and Quality Control Research of ATPR,TQ463
  8. Preparation and Evaluation on the Toxicological Safety and Stability of Deer Blood Wine,TS262.91
  9. The Research of Supramolecular Complexes of Edaravone and Cyclodextrins,R943
  10. The Comparative Study of the Reading Part of the Two Editions from Beijing University Press and People Education Press for Junior Chinese,G633.3
  11. Study on the Preparation Technology and Quality Standard of Danggui Dropping Pills,TQ461
  12. Experiment Study on the Effect of Hybrid Coat in Closing of Dentinal Tubules,R781.2
  13. Preparation of Casein Phosphopeptides and Studies on Its Calcium－holding Ability,TQ936.16
  14. Study on Preparation and Physicochemical Properties of Grass Carp Collagen Peptides,TS254.9
  15. Exploratory Studies on the Effective Fractions of Tianshu Capsule,R283
  16. To Study the Techniques for Purification of Nature Products by High-speed Counter-current Chromatography(Ⅱ),R284
  17. Preparation and Antioxidant Activity of Phenylethanoid Glycosides from Cistanche Salsa,R284.2
  18. Studies on Preparation Technology, Quality Standard and Preliminary Pharmacodynamic of Qixian Granules,R285
  19. Preparing for CET: An Investigation into CET Preparation Courses,H319
  20. Study on the Formation Mechanism and Value-added of Real Estate Value Chain,F293.3
  21. Formation Mechanism and Prevention Countermeasures of Karst Ground Collapse in Linyi Urban District,P642.26

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net  Mobile