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Online since: August 2016
Authors: Toemsak Srikirin, Tanakorn Osotchan, Santi Pumkrachang, Syahril bin Zainudin, Juthaporn Tangkijpaisarn
This epoxide is the most widely used for structure adhesive.
Quantum chemistry calculation program offers many types of molecular and quantum mechanics calculations [4].
Molecular structure of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate for a) close and b) open epoxide ring models and simulated vibrational spectra of c) close and d) open epoxide ring structures.
Ganguly, A semi-empirical and density functional study on the origin of regioselective epoxy-ring opening of 2’3’-lyxoanhydrothymidine, Journal of Molecular Structure (Theochem). 673 (2004) 127–132
Online since: January 2017
Authors: Gen Liang Hou, Bi Song, Chao Hui Liu, Jian Jian Wang, Xun Jia Su, Si Ran Li
It has the advantages of compact structure, uniform thickness, high hardness, good corrosion resistance and wear resistance [1].
Phosphorus content in electroless nickel phosphorus plating has a direct impact on deposition of nickel and phosphorus in coating which determines its organizational structure.
With the increase of phosphorus content, the state of the electroless nickel phosphorus alloy coating structure is changing from crystal (with phosphorus mass fraction: 1%~6%) to mixed state (with phosphorus mass fraction:6%~9%)and then to amorphous state(with phosphorus mass fraction:9%~15%).
In view of the different environment chemistry nickel plating, the plating solution formula is also adjusted.
[9] Jiang Jianpeng, Yu Hongying etc.The mass fraction of phosphorus of electroless nickel plating on magnesium alloy surface structure and properties of the Influence[J], Plating and Surface finishing, 27 (4),:20~22
Online since: June 2015
Authors: Romualdo Rodrigues Menezes, Danubia Lisbôa da Costa, Rosiane Maria da Costa Farias, Aluska Nascimento Simões Braga, Gelmires de Araujo Neves
Observing the results, it is possible to notice that the addition of alumina favored the formation of a more resistant structure, especially when the use of fine alumina, because the smaller particle size probably favored a better dissolution of the alumina.
Probably, the reduction of the particle size of the incorporated alumina, in the fine alumina case, probably contributed to a better dissolution of the added alumina favoring the formation of more aluminate species (Al(OH)4-) available in the dissolution reaction necessary for the condensation of the structure and formation of the gel phase and promoting the obtainment of a more resistant microstructure.
The water has an important role in the final structure of the geopolymer participating of its structure (Mn((SiO2)z–AlO2)n_wH2O).
Davidovits: Geopolymer Chemistry and Applications. (2nd edition Geopolymer Institute Saint-Quentin, France. 2008)
Online since: March 2012
Authors: M.U. Sharma, Vinay Gupta, V Bhasker Raj, Harpreet Singh, A. Theodore Nimal, Monika Tomar
Introduction Physics, chemistry, and technology of sensors require a better understanding of both the bulk and surface properties of the sensing materials.
The crystallographic structure of the as grown oxide films have been investigated using X ray diffractometer.
Target Zn metal Sn metal Te Ti metal Pressure (mT) 20 12 10 10 Gas composition 70% Ar + 30% O2 100% O2 50% Ar + 50% O2 50% Ar + 50% O2 Power (W) 300 150 50 150 Results and Discussions Films Characterizations The XRD pattern of ZnO thin film shows only reflection corresponding to (002) plane of wurtzite ZnO structure, indicating growth of highly oriented films with c axis normal to the surface of quartz substrate.
The surface free energy of (002) plane in wurtzite ZnO structure is reported to be minimum as compared to other planes [11].
XRD spectra of SnO2 films show that films are polycrystalline with at 2q = 26.50, 33.89 and 51.79 corresponding to (1 1 0), (1 0 1) and (2 1 1) planes, which are in good agreement to the reported values for rutile structure [8].
Online since: March 2008
Authors: Jorma Hölsä, Mika Lastusaari, Dariusz Hreniak, Wiesław Stręk, Robert Fedyk, Witold Łojkowski, Mikko Tenho, Vesa Pekka Lehto
Sokolowska 29/37, PL-01142 Warsaw, Poland, 2 University of Turku, Department of Chemistry, FI-20014 Turku, Finland, 3 Polish Academy of Sciences, Institute of Low Temperature and Structure Research, P.O.
The X-ray diffraction patterns of the Y3Al5O12:Nd 3+ ceramic samples confirmed their structural purity, since only reflections resulting from the cubic Y3Al5O12 structure (space group d3Ia , No. 230, Z = 8 [16]) were observed (Fig. 1).
No structure was observed in the texture pole figures (Fig. 4), which indicates a random orientation for the crystallites on the surface of the Y3Al5O12:Nd3+ nanoceramics.
This is a result of good stress distribution during the compaction, the nanoscale crystallite sizes favoring a random orientation and the cubic crystal structure of Y3Al5O12, which should not result in plate- or needlelike crystallites with a tendency for texture.
Online since: April 2015
Authors: Ewa Rudnik
Electrochemical codeposition of nickel and tin from gluconate solutions Ewa Rudnik AGH University of Science and Technology, Faculty of Non – Ferrous Metals Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals Al.
Structure of the deposits was analyzed by X-ray diffractometry (Rikagu diffractometer, CuKα radiation).
It was found that decrease in the deposition potentials was accompanied by the gradual change in the morphology of the alloys from separate crystals via columnar structures to the cauliflower-like deposits.
Phase analysis of the Ni-Sn deposits (Fig. 8) has shown modification of the deposits structure with increased nickel percentage in the alloys.
Acknowledgement Author thanks Grzegorz Włoch, Ph.D. from Department of Structure and Mechanics of Solids at the Faculty of Non-Ferrous Metals of AGH University of Science and Technology for his help during SEM observations.
Online since: January 2010
Authors: Byung Nam Kim, Keijiro Hiraga, Koji Morita, Hidehiro Yoshida
The present paper aims to briefly summarize our recent data on the superplastic flow and creep in oxide ceramics and to describe how an atomistic or electronic structure can effectively improve the high temperature tensile ductility or creep resistance.
The result in Fig. 1 suggests that the grain boundary chemistry significantly influences the grain boundary sliding and/or grain boundary diffusion in the TZP.
HRTEM observation and atomistic analysis techniques such as EDS, electron energy-loss spectroscopy (EELS) [13] and X-ray absorption fine structure (XAFS) [6] are Fig. 6.
In contrast, the controlling of the grain boundary nanostructure means the designing of atomic structure and interatomic interaction of grain boundary.
The designing of grain boundary nanostructure will be of importance for fabricating high-performance ceramics in the near future, because the grain boundary structure often influences not only the superplasticity but also other matter transport phenomena such as sintering and ionic conduction [14].
Online since: February 2011
Authors: Konstantin Borodianskiy, Michael Zinigrad, Aharon Gedanken
Aluminum A356 Reinforcement by Carbide Nanoparticles Konstantin Borodianskiy1,2,a, Michael Zinigrad1,b, Aharon Gedanken2,c 1 Advanced Materials Laboratory, Materials Research Center, Ariel University Center of Samaria, Ariel 40700, Israel 2 Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel akonstantinb@ariel.ac.il, bzinigrad@ariel.ac.il, cgedanken@mail.biu.ac.il Keywords: Aluminum A356, carbide nanoparticles, mechanochemical activation, grain-size aluminum strengthening mechanism.
It is evident that the average grain size of the alloy decreases, and the structure of the material becomes finer.
These particles function as crystallization centers in the liquid aluminum and will cause the formation of fine-structured aluminum because of their great amount.
As a result of aluminum fine structure formation, the mechanical properties of the alloy increase.
According to this process, grain size reduction and formation of fine aluminum structures improves mechanical properties.
Online since: September 2007
Authors: Rositza Yakimova, Anita Lloyd Spetz, Mikael Syväjärvi, Gholam Reza Yazdi, R.M. Petoral Jr., C. Vahlberg, K. Uvdal
Yakimovag Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden a rodpe@ifm.liu.se, byzdi@ifm.liu.se, ccecva@ifm.liu.se, dmsy@ifm.liu.se, espetz@ifm.liu.se, f kaj@ifm.liu.se, groy@ifm.liu.se Keywords: Biosensors, Surface functionalization, SAM, Organosilanes, XPS, Contact angle Abstract.
The structure of the molecules is shown in Fig, 1.
Structure of MPTMS molecules.
The structure and the morphology of the SAM are confirmed by using contact angle measurement, XPS and AFM.
In terms of surface structure, MPTMS molecules form well-ordered layers with thiol headgroups uniformly distributed on the uppermost surface, as shown by angle dependent XPS analysis.
Online since: May 2012
Authors: Mikael Syväjärvi, Rositza Yakimova, Valdas Jokubavicius, Jean Camassel, J.W. Sun, T. Robert, Sandrine Juillaguet
Camassel3,g 1 Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden 2 Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France 3 CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France a jiasu@ifm.liu.se, b robertt@univ-montp2.fr, c valjo@ifm.liu.se, d sandrine.juillaguet@univ-montp2.fr, e roy@ifm.liu.se, f misyv@ifm.liu.se g jean.camassel@univ-montp2.fr, Keywords: Stacking faults, low temperature photoluminescence Abstract.
Four series of quantum-well like structures appearing in between the 6H-SiC excitonic emissions (around ~ 2.99 eV) and the bulk-like 3C-SiC excitonic lines (at ~ 2.39 eV) are the specific signatures of stacking faults.
The second series of features are made of (large) structures, qualitatively similar to the 3C matrix signal but appearing in between the bulk 6H and 3C-SiC NBE emission lines.
In between, four series of large, broad structures manifest with fourfold component structures.