Search results

Preparation and Characterization of Dioxanone and Poly (dioxanone) Kuilin Deng*, Wenhui Jin, Fuchen Zhang, Chunxiu Li, Huijuan Shen, Xin Ma, Xueying Fan, Meng Wang College of Chemistry & Environmental Science, Hebei University, Baoding 071002, China Tel: +86-0312-5971137; Fax: +86-0312-5079525; dkl369@hbu.edu.cn Keywords: Dioxanone, Polydioxanone, Copper chromite, Medical polymer materials Abstract.
The integral area ratio of the three peaks is 1:1:1 and it coincides with PDO molecular structure.
PDO and its polymers PPDO structure were confirmed with IR spectroscopy, and NMR spectroscopy.

Recent research achievements and machining accuracy developed by several famous universities were introduced and the principle and structure of the machining device were explained, according to the new demands for the future, the tendency of ultra-smooth surface abrasive flow polishing technology was suggested, especial emphasis on the precise polishing tool and the technology of soft contact between abrasive and workpiece.
In the method the ultrasonic was used to make abrasive high-frequency vibration, and the relative movement between abrasive and workpiece caused the shock effect, the physics and chemistry action between the workpiece and abrasive flow were used to attained the ultra-smooth surface polishing effect[9], the polishing device was showed in Fig. 5.

Deposition rate, film structure, compositional analysis and optical properties are studied as a function of working pressure.
As increasing working pressure, the film structure changes from Zr-O solid solution, to monoclinic structure with preferred orientation and finally to randomly oriented nanocrystalline structure.
Moreover, under same deposition condition, the behavior of film structure on silicon is similar to that on quartz substrates, indicating that various substrate materials (e.g. silicon and quartz) might have little influence on the film structure.
Besides, the evolution of film structure in our work is also rather different from that of Koski et. al.
Richardson: Oxide Ceramic, Physical Chemistry and Technology (General Ceramics, Haskell, NJ, 1985)

The polarization properties of a new structure of high birefringence polarization maintaining photonic crystal fibers were explored, which were consisted of elliptical-holes and near elliptical core triangle lattice of hexangular structure based on polymer.
Because of the difficulty to fabricate the shape of elliptical holes, in this paper, we proposed a new structure high birefringence polarization maintaining PCF with near elliptical core design by three adjacent central holes missing and triangular lattice squeezed hexangular structure air holes cladding.
Design principle and theoretical model The cross-section of near elliptical core squeezed hexangular structure PCF is indicated in Fig. 1.
The structure parameters are characterized by holes diameter d and holes pitch Λ respectively.
[7] ZHANG Ya-ni, WANG Li-li, WANG Xue-zhong: Chemistry Fabrication of polymer Photonic Crystal Fibers with High Polarization Maintaining Properties.

When the process monitoring model based on PCA is established, outliers would destroy covariance structure of model, so monitoring model deviations will affect the monitoring results.
There are outliers in the original data, which damaged the covariance structure, and the robust scaling detection is not accurate enough for the initialization estimates of the mean and covariance of n samplings, which will lead to the result that a small fraction of outliers is still not detected and outlier detection performance be affected.
Analytical Chemistry,1998,70(11):2372-2379
[8] Helge H,Liang Y ,Kvalheim O M.Trimmed object projections:a nonparametric robust latent-structure decomposition method[J].Chemometrics and Intelligent Laboratory Systems, 1995(27):33-40

This reaction releases hydrogen which creates the porous structure.
Exiting gas leaves a porous structure in the material.
Samples with porous structure (AAC) were created in size of 100x100x100 mm cubes.
Structure and properties of aerated concrete: a review. 
The Chemistry of Al-Tobermorite and its Coexisting Phases AT 175 ℃.

Athos da Silveira Ramos, Rio de Janeiro, Brazil alais.alves@cefet-rj.br, barissa_sn@hotmail.com, celainevazquez@poli.ufrj.br, dsilvio.debarros@gmail.com Keywords: geopolymer, environment, sustainable development, composite structures Abstract.
Chronological survey of early publications AUTHOR YEAR TITLE DESCRIPTION Glukhovsky 1959 Soil Silicate Publication on alkaline cements in Gostroiizdat Publish (State Publishing Committee), USSR Glukhovsky 1965 Soil Silicate: Their properties, technology and manufacturing and fields of applications Doctoral thesis on alkaline cements, Institute of Civil Engineering, Kiev, USSR Davidovits 1972 Sintered composite panels First patent on polycondensation with kaolin and sodium hydroxide (SILIFACE®) Davidovits 1975 Agglomerating compressible mineral materials in the form of powder, particles or fibers First patent on sodium-based polyciliate Davidovits 1976 Solid phase synthesis of mineral block polymer by low temperature polycondensation of alumina-silicate polymers Article published in IUPAC Symposium, with proposal of terminology of silicosis chemistry and creation of the term "geopolymer" Davidovits e Sawyer 1985 Early high-strength mineral polymer Patent on sodium and potassium polyciliate
Lines of Research on Geopolymers Some other characteristics, that can be highlighted and turn it potentially usable in civil construction, are: resistance to degradation by chemical components of acid pH, with performance superior to Portland cement in some cases [12]; low permeability due to the low apparent porosity that results in an item capable of safely encapsulating substances can be used to eliminate toxic products; as well as a product resistant to freeze-thaw cycles, due to its two-dimensional lattice structure, which allows the water of its interior to evaporate without damage to the material.
Structure, Design and Applications of Geopolymeric Materials.
Proceedings of the 3rd International Conference on Deformation Processing and Structure of Materials.

Materials Used for the Test Specimens Concrete from an existing structure.
One of the tested materials was concrete taken from an existing monolithic structure (CN).
The diameter of the drilled cores taken from the structure was chosen to cause the smallest possible damage to the structure while respecting the recommendations in [1] and [2].
The alkaline activator was prepared from potassium water glass (Vodní sklo a. s. | Water-glass – Green chemistry for a sustainable future, Prague, Czech Republic) and potassium hydroxide in such an amount as to achieve the above-mentioned silicate modulus.
Patrik Bayer, both from the Institute of Chemistry at FAST BUT, for their support concerning the preparation and modification of the test specimens.

Electrocatalysis as a catalytic process involving oxidation or reduction through the direct transfer of electrons is of key importance subject in various fields of chemistry and associated sciences.
Fig. 2 shows a schematic illustration of the structure of the field of heterogeneous electrocatalysis [2].
As a result of the changes in the electrode potential, its morphology and surface structure may become subject to changes and therefore the electrocatalytic activity is a function of potential.
Therefore, one of the main goals of contemporary electrocatalysis is maximization of the surface accessibility by the use of the electrode materials characterized by the structures with meso- or macropores [32].
It was postulated that the surface structure strongly effects on the decomposition process of methanol.

A novel synthesis route for a MCM-41 structure with Y zeolite seeds colloidal has been developed.
The XRD pattern of dried YP is ploted in Fig. 2, showing no Bragg peaks, which means Y zeolite structure has been fully destroyed during the HCl dissolution.
No diffraction peak is observed in the region 2θ=10~50o, which indicates the absence of microporous crystal-structure.
The wall thickness (t) of the mesopore structure in the composite can be estimated from equation, here D refers to pore diameter, as 2.21 nm.
Zeolite chemistry and catalysis.