| 1. |
|
|
| 2. |
- Tian, Yupeng, et al.
(författare)
-
Two novel two-photon polymerization initiators with extensive application prospects
- 2004
-
Ingår i: Chemical Physics Letters. - : Elsevier. - 0009-2614 .- 1873-4448. ; 388:4-6, s. 325-329
-
Tidskriftsartikel (refereegranskat)abstract
- Two novel two-photon polymerization initiators, 10-ethyl-3-E-(4-(N,N′-di-n-butylamino)styryl)phenothiazine 5 and 10-ethyl-3,7-E,E-bis(4-(N,N′-di-n-butyl amino)styryl)phenothiazine 6, have been efficiently synthesized with room temperature solid phase Wittig reaction. Two initiators were found to exhibit good single-photon fluorescence emission and their quantum yields, lifetimes and solvent effects have been studied in detail. Two-photon fluorescence spectra were investigated under 800 nm fs laser pulse and two-photon absorption (TPA) cross-sections of the initiators have been evaluated by theoretical calculation.Two-photon initiating polymerization microfabrication experiments have been carried out and artificial defects were made and polymerization mechanism was also discussed.
|
|
| 3. |
- Hu, Hanmei, et al.
(författare)
-
Solvothermal synthesis of Sb2S3 nanowires on a large scale
- 2003
-
Ingår i: Journal of Crystal Growth. - : Elsevier. - 0022-0248 .- 1873-5002. ; 258:1-2, s. 106-112
-
Tidskriftsartikel (refereegranskat)abstract
- Sb2S3 nanowires with high aspect ratios have been successfully prepared on a large scale using SbCl3 and Na2S as starting materials in ethylene glycol at 200°C for 10 h. Field emission scanning electron microscopy images and transmission electron microscopy images show that the nanowires have diameters in the range of 20–100 nm and lengths up to 50 μm. Diffuse reflection spectrum indicates that the as-prepared Sb2S3 nanowires have obvious quantum size effects. The effects of reaction parameters on the growth of nanowires were discussed. A possible mechanism on the formation of the Sb2S3 nanowires was proposed.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Toprak, Muhammet S., et al.
(författare)
-
The impact of nanostructuring on the thermal conductivity of thermoelectric CoSb3
- 2004
-
Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 14:12, s. 1189-1196
-
Tidskriftsartikel (refereegranskat)abstract
- The high concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric materials, which favors an increase in their thermoelectric figure-of-merit, ZT. A novel chemical alloying method has been used for the synthesis of nanoengineered-skutterudite CoSb3. The CoSb3 powders were annealed for different durations to obtain a set of samples with different particle sizes. The samples were then compacted into pellets by uniaxial pressing under various conditions and used for the thermoelectric characterization. The transport properties were investigated by measuring the Seebeck coefficient and the electrical and thermal conductivities in the temperature range 300 K to 650 K. A substantial reduction in the thermal conductivity of CoSb3 was observed with decreasing grain size in the nanometer region. For an average grain size of 140 nm, the thermal conductivity was reduced by almost an order of magnitude compared to that of a single crystalline or highly annealed polycrystalline material. The highest ZT value obtained was 0.17 at 611 K for a sample with an average grain size of 220 nm. The observed decrease in the thermal conductivity with decreasing grain size is quantified using a model that combines the macroscopic effective medium approaches with the concept of the Kapitza resistance. The compacted samples exhibit Kapitza resistances typical of semiconductors and comparable to those of Si-Ge alloys.
|
|
| 7. |
- Uheida, Abdusalam, et al.
(författare)
-
Extraction of platinum(IV) with nonylthiourea dissolved in chloroform from hydrochloric acid media
- 2003
-
Ingår i: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 21:6, s. 827-840
-
Tidskriftsartikel (refereegranskat)abstract
- The extractant nonylthiourea (NTH) in chloroform has been investigated for the extraction of Pt(IV) from chloride solutions at ionic strength of I = 4.0 M and at 22degreesC. It has been found that chloride concentration has a negative effect on the extraction equilibrium, while proton concentration has no effect. The numerical analysis of the equilibrium data has shown that the extraction of PtCl62- with NTH can be interpreted by the formation Of PtCl4(NTH) and PtCl4(NTH)(4) species with their respective equilibrium constants of log K-11 = 5.06 +/- 0.01 and log K-14 = 14.12 +/- 0.04 in 4 M HCl. FTIR spectra of the free NTH and the NTH-Pt(IV) complex were studied to obtain some information on the interaction between Pt(IV) ions and NTH molecules.
|
|
| 8. |
- Uheida, Abdusalam, et al.
(författare)
-
Selective extraction of palladium(II) from chloride solutions with nonylthiourea dissolved in chloroform
- 2002
-
Ingår i: Solvent extraction and ion exchange. - : Informa UK Limited. - 0736-6299 .- 1532-2262. ; 20:6, s. 717-733
-
Tidskriftsartikel (refereegranskat)abstract
- The extraction of Palladium(II) [Pd(II)] from hydrochloric acid solutions with nonylthiourea (NTH) dissolved in chloroform at a constant ionic strength of LOM has been studied. The extraction of Pd(II) has been investigated as a function of the concentration of the extractant, chloride ion, and proton concentrations as well as extraction temperature. The distribution data have been treated graphically and numerically. The analysis of the experimental data has shown that Pd(II) is extracted as PdCl2 . (NTH) and PdCl2 . (NTH)(2) species with the respective extraction constants of log K-11 = 5.0 +/- 0.1 and log K-12 = 9.1 +/- 0.1. The back-extraction of Pd(II) from the organic phase using different stripping reagents has been examined. The selectivity of NTH for Pd(II) against Pt(IV), Rb(III), Cu(II), Fe(III), and Zn(II) has also been investigated.
|
|
| 9. |
- Uheida, Abdusalam, et al.
(författare)
-
Thermodynamic modeling of extraction equilibria of platinum and palladium with nonylthiourea from hydrochloric acid media
- 2004
-
Ingår i: Separation science and technology (Print). - : Informa UK Limited. - 0149-6395 .- 1520-5754. ; 39:15, s. 3665-3677
-
Tidskriftsartikel (refereegranskat)abstract
- Models of extraction equilibria of Pt(IV) and Pd(II) with Nonylthiourea (NTH) from HCl media have been studied. The conditional equilibrium constants and the stoichiometry of the extracted species of Pt(IV) with NTH at different ionic strengths obtained by numerical analysis using the LETAGROP-DISTR program are reported. The dependence of the extraction constant values on the ionic strength has been analysed using the Specific Interaction Theory (SIT), from which the respective thermodynamic equilibrium constants of the extraction of Pt(IV) and Pd(II) with NTH have been determined. The thermodynamic equilibrium constants determined for Pt(IV) are log K-11o=5+/-1 and log K-14(o)=14.6+/-0.2, while for Pd(II) log K-11(o)=4.9+/-0.1 and log K-12(o)=9.17+/-0.08. The interaction coefficients, epsilon, for the pairs (H+, PtCl62-) and (H+, PdCl42-) have also been estimated to be 0.30+/-0.08 and 0.41+/-0.02, respectively.
|
|
| 10. |
- Uheida, Abdusalam, et al.
(författare)
-
Transport of palladium(II) through hollow fiber supported liquid membrane facilitated by nonylthiourea
- 2004
-
Ingår i: Journal of Membrane Science. - : Elsevier BV. - 0376-7388 .- 1873-3123. ; 241:2, s. 289-295
-
Tidskriftsartikel (refereegranskat)abstract
- The facilitated transport of Pd(II) from chloride media has been investigated through a hollow-fiber supported liquid membrane using nonylthiourea (NTH) as a carrier. The influence of the chemical conditions on the permeability of Pd(II) is reported. A model is presented that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of carrier and its metal complex through the organic membrane. The diffusion resistances through organic membrane (Delta(org)) and through aqueous layer (Delta(aq)), respectively, have been calculated from the proposed model. The permeability of Pd(II) seems to be governed by the diffusion of Pd(II) species through the hollow fiber supported liquid membrane with PdCl2(NTH)(2) as a predominant carrier and PdCl2(NTH)to a lesser extent, though both have similar diffusion coefficients.
|
|
