Search results

This is most noticeable for tmр with a separate anomaly for methane and ethane (increased tmр), and it is taken into account by the cyclic hexameric structure for methane, trimer structure for ethane, dimer structure for following alkanes [12].
These structures have higher melting and boiling points.
Lievens, Unraveling the atomic structure, ripening behavior, and electronic structure of supported Au20 clusters, Sci.
House, Inorganic Chemistry, California, Elsevier (2010)
[18] Search for Species Data by Chemical Name, NIST Chemistry WebBook, U.S.

Fig.1 Structure of one tetramer unit of the AlPO4 precursor, ACPE.
The thicker white bonds outline the central cage of the structure.
It should be noted that the volume yield of ACPE is much greater than the 5% that might have been expected simply from the difference in crystal structures between ACPE and the tridymite crystal form of AlPO4.
Experiments show that the AlPO4 formed is porous, typically 30%, in line with structures formed in SiC and Si3N4 precursors [5].
However despite the differences in chemistry and volume yield the behaviour on heating was very similar for all of the precursors.

Introduction The olivine structure of lithium iron phosphate (LiFePO4) as a kind of cathode materials in lithium-ion battery was found by J B Goodenough’s group [1].
The structure, morphology and electrochemical properties of prepared materials were characterized by different analyses.
The structure of synthesized materials was derived from X-ray diffraction (XRD: D/max-3B, Rigaku) data by using CuKa radiation.
The ratio of the two carbon sources will change the structure, morphology and electrochemical performance of LiFePO4/C composite materials.
Ahn, et al: Journal of Physics and Chemistry of Solids Vol.69 (2008),p. 1257 [5] Y.D.

The structure of Mg3Si2O5(OH)4 consists of Si-centered tetrahedrons joined to layers of octahedral Mg hydroxides, as shown in Fig.1.
The ionic radius of Fe3+ is smaller than that of Mg2+ and the valence bond of Fe3+ is different from that of Mg2+, so the structure of Mg3Si2O5(OH)4 can be rearranged to form a nanotube structure in the Fe3+ doped reaction system.
Fig.1 The structure of Mg3Si2O5(OH)4 In the present work, nanometer Fe2O3，MgO and SiO2 prepared by special liquid-phase precipitation method were chosen as precursors and Fe2O3 and MgO were co-precipitated, all precursors were treated under under alkaline hydrothermal condition in order to synthesize lizardite.
As shown in Fig.3, all samples show layered structures and serious agglomerations.
[3] XU Bin-Shi, Nano Surface Engineering, Beijing Chemistry Industry Press;2004

The micro-assemblies with average size of 1~2 μm are consisted of several uniform nanoplates and show face centered cubic structure.
Five diffraction peaks are observed at 38.1 °, 44.4 °, 64.5 °, 77.5 ° and 81.6 ° respectively, which agree well with the (111), (200), (220), (311) and (222) reflections of the face centered cubic structure for metallic silver (JCPDS File NO. 04-0783 from ASTM).
But the consisted particles in the micro-assemblies exhibited nanoplate-like structure, and the small nanoparticles disappeared (seen in Fig. 1b and 2b).
This novel silver structure is expected to behave fascinating properties of chemistry, physics and electronics.

The structure of piezoelectric ceramics is perovskite and crystalline grain shows a block shape.
Compared with other non-conventional processes of soft chemistry, such as sol-gel and coprecipitation, the hydrothermal crystallization reaction has a good ability in control of the crystallization, crystal size, and morphology of the products in a shorter time. [5] The objective of this paper was to prepare lead-free piezoelectric ceramic K1-xNaxNb1-ySbyO3 powders by hydrothermal routes.
The morphology, crystallite size and phase structure of the samples were characterize by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM).
Then, we observed and measured its structure and performance.
As shown in Fig. 2, the K1-xNaxNb1-ySbyO3 ceramics possess a pure perovskite structure.

The structure of the product was confirmed by FTIR, 1HNMR and ESI-MS.
The water solubility of MCT-β-CD is 0.40 g/mL at room temperature. 1 Introduction Cyclodextrins (CDs) can be easily obtained by enzymatic degradation of starch, the cyclic glucopyranose structure provides the cyclodextrin with the promising application as oil encapsulation [1].
Then the chemical structures of the acquired product were investigated. 2 Experimental 2.1 Materials β-CD was bought from Kelong chemical Co.
The chemical structures were confirmed by FTIR, 1H-NMR and ESI-MS.
Acknowledgements This research was funded by Science and Technology Department of Zhejiang Province (Xinmiao Talent plan), Zhejiang Provincial Top Key Academic Discipline of Applied Chemistry and Eco-Dyeing & Finishing Engineering and Zhejiang Provincial Key Innovation Team (No.2010R50038).

The structure, morphology and luminescent property of the resultant powders were characterized by X-ray diffraction (XRD), transmission electron microcopy (TEM), scanning electron microcopy (SEM), and photoluminescence (PL), respectively.
Introduction The control of the morphology and architecture of inorganic materials at all dimensions from the nanoscale to microscale have rapidly developed into a promising field in materials chemistry, due to their unique size and shape-dependent properties [1-5].
Cadmium molybdate (CdMoO4) is an interesting material owning to its excellent optical, chemical properties and electronic structure [9–11].
They have scheelite structure with tetragonal crystal system and have I41/a space group symmetry [15-18], which well consistent with the reported date (JCPDS: 85-0888).
Changes of microstructure and size would modify the electronic structures of MMoO4, influencing the carries excited from the valence band to the conduction band, which then relax their energy on the product surface, leading to variations in luminescence.

We came to the conc- lusions that crystallization properties of PPS are changed under the influence of magnetic field; magnetic field promotes the perfection of the crystalline structure but inhibits the crystallinity.
Introduction The properties of polymeric materials depend deeply on aggregated structure primarily resting with cryst- allization and orientation [1].
Polyphenylene sulfide(PPS), as a typical crystalline polymer with the features of soft matter[11], ha- ve symmetrical structure, the molecular main chain is alternated by benzene and sulfur atoms, the glass transition temperature is only 85˚C, and its melting point(Tm) reaches up to 280˚C, therefore, the performance of PPS, particularly its resistance to high temperature largely depends on its degree of crystallization[12].
Fig. 4 tells us pulsed magnetic field encourage polymer’s oriented crystalliza- tion resulting in a more orderly polymer structure.
Vol. 4 (2001), p. 50 [10] Levin M N, Postnikov V V, Matveev N N: Effect of the pulsed magnetic field on the crystallization and melting of poly(ethylene oxide) [J].Russian Journal of Physical Chemistry.

Well-ordered 2-dimensional (2D) hexagonal and 3-dimensional (3D) cubic mesoporous silicon oxide thin films prepared using triblock Poly(ethylene oxide)-Poly(Propylene oxide)-Poly(ethylene oxide) copolymer species (P123, F127) as the structure-directing agents, are studied by positron beam analysis in parallel with X-ray reflection measurements.
Introduction Surfactant-templated silicon oxide films with tailored mesoporous structures and high surface area have attracted great interest in recent years, as favoring industrial application in the fields of ultra-large scale integrated circuits, sensors, etc.
Positron annihilation lifetime and Doppler broadening as well as positronium time-of-flight (Ps-TOF) measurements based on a positron beam have been frequently utilized to characterize the pore size, pore interconnectivity, porosity, pore inner-surface chemistry as well as pore tortuosity for films with random pore orientation [1].
In the current experiment, well-ordered cubic and hexagonal mesoporous silica thin films prepared using triblock Poly(ethylene oxide)-Poly(Propylene oxide)-Poly(ethylene oxide) copolymer species (Pluronic P123, F127) as structure-directing agents, are presented as specimens for positron beam analysis in parallel with synchrotron radiation X-ray reflection measurements.
To clarify that such discrepancy is not originated from big differences between chemical structures of the two films, IR measurements were carried out.