| 1. |
- Bo, Qi-Bing, et al.
(författare)
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Simple directed material design through in situ substitution of proton with Cu+ ions
- 2009
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Ingår i: Journal of Inorganic and Organometallic Polymers and Materials. - : Springer Science and Business Media LLC. - 1574-1443 .- 1574-1451. ; 19:4, s. 485-493
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Tidskriftsartikel (refereegranskat)abstract
- A new inorganic-organic hybrid material (C10H8N2H)2(Mo8O26) · 2NH4 (1) was prepared under solvothermal conditions (H2O/ethanol), which was then used as a starting material in the synthesis of another material, (C10H8N2Cu)2(Mo8O26) · 2NH4 (2). Each compound has been characterized by single-crystal X-ray diffraction, X-ray powder diffraction, elemental analysis, thermogravimetric analysis, fluorescence, FT-IR, and bond valence sum calculations. The comparative study focuses on the transformation and structural change between 1 and 2, which arises from the simple substitution of the proton in 1 with the Cu+ ions. The other surprising feature is that Cu+ ions can not only directly be used to substitute the proton of 1 but also ameliorate its photoluminescence property. It means that 1 appears to have recognizable functional protons in the solid-state structure and, hence, can very well be considered as an ideal precursor agent to design the functional materials with special architectures and photoactive properties.
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| 2. |
- Zhao, Guang-Jiu, et al.
(författare)
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Photoinduced intramolecular charge transfer and S-2 fluorescence in thiophene-pi-conjugated donor-acceptor systems : Experimental and TDDFT studies
- 2008
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 14:23, s. 6935-6947
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical methods were used to study newly synthesized thiophene-pi-cojugated donor-acceptor compounds, which were found to exhibit efficient intramolecular charge-transfer emission in polar solvents with relatively large Stokes shifts and strong solvatochromism. To gain insight into the solvatochromic behavior of these compounds, the dependence of the spectra on solvent polarity was studied on the basis of Lippert-Mataga models. We found that intramolecular charge transfer in these donor-acceptor systems is significantly dependent on the electron-with-drawing substituents at the thienyl 2-position. The dependence of the absorption and emission spectra of these compounds in methanol on the concentration of trifluoroacetic acid was used to confirm intramolecular charge-tranfer emission. Moreover, the calculated absorption and emission energies, which are in accordance with the experimental values, suggested that fluorescence can be emitted from different geometric confirmations. In addition, a novel S-2 fluorescence phenomenon for some of these compounds was also be observed. The fluorescence excitation spectra were used to confirm the S-2 fluorescence. We demonstrate that S-2 fluorescence can be explained by the calculated energy gap between the S-2 and S-1 states of these molecules. Furthermore, nonlinear optical behavior of the thiophene-pi-conjugated compound with diethylcyanomethylphosphonate substituents was predicted in theory.
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| 3. |
- Bo, Qi-Bing, et al.
(författare)
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A new family of 3D 3d-4f heterometallic frameworks comprising 1D inorganic lanthanide ladders and organic Cu-bipyridine chains
- 2008
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Ingår i: CrystEngComm. - : Royal Society of Chemistry (RSC). - 1466-8033. ; 10:2, s. 232-238
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Tidskriftsartikel (refereegranskat)abstract
- A new family of the 3D heterometallic coordination polymers [{Ln2(SO4)2(H2O)2(pydc)2Cu2 (bpy)2·2(H2O)}]n (Ln = Sm ( 1), Eu ( 2), Gd ( 3), Tb ( 4) and Dy ( 5); pydc = 2,6-pyridine-dicarboxylate anion; bpy= 4,4-bipyridine) have successfully been synthesized under solvothermal conditions (H2O/ethanol). All the coordination polymers obtained were characterized by elemental analysis, FT-IR analysis, differential thermal analysis/thermogravimetry (DTA/TG), fluorescent spectra and single crystal X-ray diffraction analysis. The most intriguing structural feature is that all the compounds exhibit 3D frameworks with 1D inorganic lanthanide ladders and organic CuI-bipyridine chains, which represent two types of 3d/4f coordination polymers (form I: Ln = Sm and Eu; form II: Ln = Gd, Tb and Dy) as the result of a so-called gadolinium break effect. Additionally, compounds 2 and 4 showed the characteristic emission spectra of the EuIII and TbIII ions, respectively, and appeared to have good fluorescence properties, while 1, 3 and 5 emitted fluorescence resembling CuI complexes. To our knowledge, the investigation of the
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| 4. |
- Chen, S., et al.
(författare)
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Coffin-Mansson equation of Sn-4.0Ag-0.5Cu solder joint
- 2009
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Ingår i: Soldering and Surface Mount Technology. - : Emerald. - 1758-6836 .- 0954-0911. ; 21:2, s. 48-54
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to fit Coffin-Manson equation of Sn-4.0Ag-0.5Cu lead free solder joint by using results of solders joint reliability test and finite element analysis. Also to present a novel device for solder joint reliability test. Design/methodology/approach: Two-points bending test of Sn-4.0Ag-0.5Cu lead free solder joint was carried out at three deflection levels by using a special bending tester that can control displacement exactly by a cam system. The failure criterion was defined as resistance of solder joint getting 10 percent increase. The X-section was done for all failure samples to observe crack initiation and propagation in solder joint. Finite element analysis was presented with ANSYS for obtaining shear strain range, analyzing distribution of stress and strain and supporting experimental results. Findings: The experimental results indicate that the fatigue life decreased obviously with the displacement increased. By using optical microscope and SEM photographs, two kinds of failure mode were found in solder joint. The majority failure mode took place at the bottom corner of solder joint under the termination of resistor initially, and propagated into the solder matrix. Another failure mode was delamination. It appeared at the interface between the termination of resistor and its ceramic body. The distribution status of stress and strain in solder joint and the calculation results of shear strain range at different deflection levels were obtained from simulation result. The Coffin-Manson equation of Sn-4.0Ag-0.5Cu lead free solder joint was fitted by combining experimental data with result of finite element analysis. Originality/value: This paper presents Coffin-Manson equation of Sn-4.0Ag-0.5Cu solder joint with two-points bending test. An effective and economical device was designed and applied.
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| 5. |
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| 6. |
- Sun, Peng, 1979, et al.
(författare)
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High temperature aging study of intermetallic compound formation of Sn-3,5Ag and Sn-4.0Ag-0,5Cu solders on electroless Ni(P) metallization
- 2006
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 425:1-2, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- The Sn-3.5Ag and Sn-4.0Ag-0.5Cu solders on Au/electroless Ni(P) metallization exhibited different interfacial morphologies after high temperature storage (HTS) at 150 °C. Ni 3 Sn 4 intermetallic compounds (IMCs) were found in the Sn-Ag system, while for the Sn-Ag-Cu system the IMCs consisted of two kinds of interfacial reactions. For the Sn-3.5Ag solder, the Ni 3 Sn 4 IMC particles lost adhesion/contact to the electroless Ni(P) layer and clear gap was observed in the samples after high temperature storage (HTS) aging for 1000 h. In the Sn-4.0Ag-0.5Cu solder joint, both (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 compounds were observed after HTS aging. Since the difference in nucleation site and growth rate for kinds of IMCs, (Cu,Ni) 6 Sn 5 was observed at top and (Ni,Cu) 3 Sn 4 at bottom when the interfacial compound layer became thicker as a function of thermal aging. Some voids were found between the electroless Ni(P) interface and the Sn-Ag solder after 168 and 500 h of thermal aging, while the clear gap between the solder and the Ni layer existed after 1000 h aging. The formation mechanism for this gap could be the interconnection and growth of the voids. In the Sn-Ag-Cu system, voids were found inside the Sn-Ni-Cu ternary interfacial compounds after 500 and 1000 h. The formation mechanism for these voids was thought to be Kirkendall effect or etching process. The interfacial layer of Sn-Ag-Cu solder on electroless Ni(P) coating showed the better thermal stable than eutectic Sn-Ag solder. © 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Sun, Zhong-Xi, et al.
(författare)
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Effects of calcination temperature on the pore size and wall crystalline structure of mesoporous alumina
- 2008
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Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 319:1, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, mesoporous alumina with different pore sizes and wall crystalline structures was synthesized at calcination temperatures over 550 °C. The characterization of the samples calcined at 550, 800, 1100, and 1300 °C, respectively, was performed using TEM, XRD, FTIR, TG/DTA, and N2 adsorption/desorption techniques. The correlation between pore size and wall crystalline structure on calcination temperature was systematically investigated.
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| 8. |
- Zhang, Wei, et al.
(författare)
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Synthesis and characterization of some new mononuclear ruthenium complexes containing 4-(un) substituted dipyridylpyrazole ligands
- 2008
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 27:4, s. 1168-1176
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Tidskriftsartikel (refereegranskat)abstract
- A mononuclear ruthenium complex [Ru(bpy)(2)(bpp)](PF6) (1) and its halogenated and nitro derivatives [Ru(bpy)(2)(Xbpp)](PF6) (bpy = 2,2'-bipyridine; bpp = 3,5-bis(2-pyridyl)pyrazole; X = Cl, 2; X = Br, 3; X = I, 4; X = NO2, 5) have been synthesized and characterized by H-1 NMR, C-13 NMR, HRMS, elemental analysis. Complexes 2-5 have been further confirmed by X-ray diffraction. Their UV-Vis and emission spectroscopies, electrochemical measurements and acid-base properties are described. The results presented here reveal that the introduction of Cl, Br, I and NO2 groups to the coordinated bpp(-) ligand makes the absorption and emission maxima of the parent complex 1 blue-shifted, the oxidation potential of the Ru-II/Ru-III couple increased and the pK(a) value decreased obviously. In addition, significant quenching of the emission by these groups is also observed.
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