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Online since: July 2018
Authors: Dong Yeop X. Oh
During the drying process to form a film, the capillary force leads to a porous structure.
(A) Parylene C (PC) coating process on a CNF film, and the chemical structure of PC.
The SEM image of the pristine CNF shows a fibrillary structure.
As the PC thickness increases, the nanofibril structure gradually disappears and the globular shape of the structure gradually appears.
The globular-shaped structure is the intrinsic surface texture of the PC coating.
(A) Parylene C (PC) coating process on a CNF film, and the chemical structure of PC.
The SEM image of the pristine CNF shows a fibrillary structure.
As the PC thickness increases, the nanofibril structure gradually disappears and the globular shape of the structure gradually appears.
The globular-shaped structure is the intrinsic surface texture of the PC coating.
Online since: May 2006
Authors: Cristina Martín, Margarita del Arco, Amalia M. Pérez Grueso, Daniel Carriazo, Vicente Rives
A collapse in the layered structure is observed when the sample is calcined at 400 ºC,
giving rise to an almost amorphous phase in which MgO starts to crystallize.
In this case a collapse of the lamellar structure is observed when the sample is calcined above 200 ºC.
The first one is due to a loss of interlayer water and the second one to layer dehydroxilation and structure collapse; a lost of 35% in weight is measured.
Conclusions This study has shown three interesting aspects about the interlayer chemistry of chromate ions in layered double hydroxides: (a) Chromate intercalated in MgAl and ZnAl LDHs has a strong interaction with brucite-like layers giving rise to a grafting process when calcined in the temperature range 100-300 ºC.
A B 0 0,2 0,4 0,6 0,8 1 p/pº Vads (ml/g) b a 10(b) Sample MgAl-CrO42 keeps its layered structure until 400 ºC, a larger temperature than that in which MgAl-Cl LDH collapses; however, in the ZnAl-CrO42 case the lamellar structure does not survive above 300 ºC.
In this case a collapse of the lamellar structure is observed when the sample is calcined above 200 ºC.
The first one is due to a loss of interlayer water and the second one to layer dehydroxilation and structure collapse; a lost of 35% in weight is measured.
Conclusions This study has shown three interesting aspects about the interlayer chemistry of chromate ions in layered double hydroxides: (a) Chromate intercalated in MgAl and ZnAl LDHs has a strong interaction with brucite-like layers giving rise to a grafting process when calcined in the temperature range 100-300 ºC.
A B 0 0,2 0,4 0,6 0,8 1 p/pº Vads (ml/g) b a 10(b) Sample MgAl-CrO42 keeps its layered structure until 400 ºC, a larger temperature than that in which MgAl-Cl LDH collapses; however, in the ZnAl-CrO42 case the lamellar structure does not survive above 300 ºC.
Online since: October 2012
Authors: Zhen Guo, Shuang Ling Wu, Xiao Qing Qu, Li Hua Cui, Jun Yan Huang
Because of a special conjugated triene structure, tung oil has high reactivity and can be polymerized to dioxane-unit macromolecule, and the existence of the olefinic bonds made intermolecular crosslinking occur.
As a result, polymer membrane of network structure was formed [2-4].
As the adding amount of tung oil was increased, the activation energy of molecules of tung oil was increscent, the polymerization reaction between monomers became strong,molecular weight got bigger, and network structure formed by the intermolecular interaction.
Because of the existence of chip hydration in the structural unit of bentonite, the edge of flake with weak positive charge was attracted to the surface of flake with negative charge, and the 3d structure was set up quickly.
Tang: Chemistry and Industry of Forest Products, Vol. 30 (2010) No.3, pp.49-52 (in Chinese)
As a result, polymer membrane of network structure was formed [2-4].
As the adding amount of tung oil was increased, the activation energy of molecules of tung oil was increscent, the polymerization reaction between monomers became strong,molecular weight got bigger, and network structure formed by the intermolecular interaction.
Because of the existence of chip hydration in the structural unit of bentonite, the edge of flake with weak positive charge was attracted to the surface of flake with negative charge, and the 3d structure was set up quickly.
Tang: Chemistry and Industry of Forest Products, Vol. 30 (2010) No.3, pp.49-52 (in Chinese)
Online since: April 2004
Authors: Hyun Chul Park, Kwang Joon Yoon, Nam Seo Goo, J.R. Haw, Kyu Young Kim
Haw
2
1Active Structure and Material Laboratory, Dept. of Aerospace Engineering
2Dept. of Material Chemistry and Engineering
Konkuk University, Kwangjin-gu, Seoul 143-701, Korea
ABSTRACT
This paper is concerned with the fatigue characteristics of LIPCA (LIghtweight Piezo-Composite Actuator) device
system.
INTRODUCTION Smart actuators can be used to control the surfaces of aircrafts and missiles, the vibration of large space structures, or as actuators for robots, etc.
Fig. 1 shows the stacking structure, materials, and neutral axis.
Goo, Design and manufacture of a lightweight piezo-composite curved actuator, Smart Materials and Structures, Vol. 11, pp. 163-168, 2002. 6.
Yoon, Behaviors and Performance Evaluation and Optimal Design of LIghtweight Piezo-composite Curved Actuator, Journal of Intelligent Material System and Structures, Vol. 12, No. 9, pp. 639-646, 2001. 7.
INTRODUCTION Smart actuators can be used to control the surfaces of aircrafts and missiles, the vibration of large space structures, or as actuators for robots, etc.
Fig. 1 shows the stacking structure, materials, and neutral axis.
Goo, Design and manufacture of a lightweight piezo-composite curved actuator, Smart Materials and Structures, Vol. 11, pp. 163-168, 2002. 6.
Yoon, Behaviors and Performance Evaluation and Optimal Design of LIghtweight Piezo-composite Curved Actuator, Journal of Intelligent Material System and Structures, Vol. 12, No. 9, pp. 639-646, 2001. 7.
Online since: April 2015
Authors: Si Qin Dalai, Bao Agula
Mesoporous CexZr1-xO2 Mixed Oxides Supported Cr-V-O Nanocatalysts for Dehydrogenation of Propane to Propene
Bao Agula1,a* and Siqin Dalai1,b
1College of Chemistry and Environmental Science, Inner Mongolia Normal University, Huhhot,010022 , P.R.
However, little attention has been paid to the formation of mesoporous structure of Ce-Zr-O catalyst supports, though the mesoporous structure would give rise to well-dispersed and stable metal catalyst particles on the surface upon calcinations and reduction because of its abundant pores and large surface, exhibiting a great potential in further improving the catalytic performance [8].
The main reflections at 28.6, 33.3, 47.5 and 56.8° of 2θ in the XRD patterns of all the samples correspond to the cubic, fluorite structure typical of CeO2, and there is no indication of the presence of other phases.
The hysteresis loop is of type H2, typical for wormhole-like mesoporous structures formed by nanoparticle assembly [10,11].
N2 adsorption analysis revealed that the surfactant-assisted method prepared Cr-V-O/ CexZr1-xO2 catalysts have wormhole-like mesoporous structure with uniform pore size distribution.
However, little attention has been paid to the formation of mesoporous structure of Ce-Zr-O catalyst supports, though the mesoporous structure would give rise to well-dispersed and stable metal catalyst particles on the surface upon calcinations and reduction because of its abundant pores and large surface, exhibiting a great potential in further improving the catalytic performance [8].
The main reflections at 28.6, 33.3, 47.5 and 56.8° of 2θ in the XRD patterns of all the samples correspond to the cubic, fluorite structure typical of CeO2, and there is no indication of the presence of other phases.
The hysteresis loop is of type H2, typical for wormhole-like mesoporous structures formed by nanoparticle assembly [10,11].
N2 adsorption analysis revealed that the surfactant-assisted method prepared Cr-V-O/ CexZr1-xO2 catalysts have wormhole-like mesoporous structure with uniform pore size distribution.
Online since: December 2013
Authors: Xiu Xia Zhang, Zhi Jun Zhou, Jun Hu Zhou, Ke Fa Cen
The first attempt to analyse chemisorption processes of NO on different carbon models employing quantum chemistry calculations was made by Kyotani and Tomita [5].
An intermediate structure M2 including a ketone and a (-NN) group is produced with an endothermicity of 128.3 kJ·mol-1.
The bond between C5 and N in intermediate M2 is ruptured via TS2 to form an open-ring structure M3.
Structure P1, which contains a ketone and a five-membered ring, is left on char and may participate in further reactions.
The bond between C2 and C3 is subsequently split off and CO molecule is released from M6 via TS7, leaving the (-NN) group on the edge of the model structure of char.
An intermediate structure M2 including a ketone and a (-NN) group is produced with an endothermicity of 128.3 kJ·mol-1.
The bond between C5 and N in intermediate M2 is ruptured via TS2 to form an open-ring structure M3.
Structure P1, which contains a ketone and a five-membered ring, is left on char and may participate in further reactions.
The bond between C2 and C3 is subsequently split off and CO molecule is released from M6 via TS7, leaving the (-NN) group on the edge of the model structure of char.
Online since: September 2013
Authors: Jiti Nukeaw, Supanit Porntheeraphat, Win Bunjongpru, Charndet Hruanun, Apirak Pankiew, Amporn Poyai, Yossawat Rayanasukha, Narathon Khemasiri, Wutthinan Jeamsaksiri, Awirut Srisuwan, Woraphan Chaisriratanakul
Introduction
The pH value is the significant parameter in wide applications for example chemistry, biochemistry, waste water, environmental and so on.
Chuo et al. [10]had introduced to ruthenium nitride sensing membrane for pH-EGFET and reviewed to other metal nitride used to sensing membrane of this structure.
The D.C. input power supplied to the system was set to 6 kW. 2.2 TiN Thin Film Characterization Crystalline structure, surface morphology and surface roughness of sputteredTiN grown at RT, 250, 350 and 450°C were obtained byGlancing Angle X-ray Diffraction (GAXRD) (model TTRAX 111 from Riagku).
At the high substrate temperature in the TiN deposition process, the oxygen atom can compoundwith Ti to form TiO2 with anatase structure (004) at 38° [11].
The sheet resistivity measurement has shown that the TiN thin film grown with the substrate heating temperature of 350°C by D.C. magnetron sputtering has the lowest sheet resistivity so this condition isoptimized for pH-EGFET structure [9].
Chuo et al. [10]had introduced to ruthenium nitride sensing membrane for pH-EGFET and reviewed to other metal nitride used to sensing membrane of this structure.
The D.C. input power supplied to the system was set to 6 kW. 2.2 TiN Thin Film Characterization Crystalline structure, surface morphology and surface roughness of sputteredTiN grown at RT, 250, 350 and 450°C were obtained byGlancing Angle X-ray Diffraction (GAXRD) (model TTRAX 111 from Riagku).
At the high substrate temperature in the TiN deposition process, the oxygen atom can compoundwith Ti to form TiO2 with anatase structure (004) at 38° [11].
The sheet resistivity measurement has shown that the TiN thin film grown with the substrate heating temperature of 350°C by D.C. magnetron sputtering has the lowest sheet resistivity so this condition isoptimized for pH-EGFET structure [9].
Online since: February 2017
Authors: Xin Sun, Xiao Jing Liu, Jing Hua Guo
Recently, crystal structure of a new material glycine-phthalic acid (GPA) crystal has been synthesized.
The density functional theory (DFT) is a popular method for the calculation of molecular structures, vibrational frequencies and energies of molecules.
The FMOs play an important role in the optical and electric properties, as well as in quantum chemistry and UV-Vis spectrum [14].
Bigdeli, Identification of the Response of a Controlled Building Structure Subjected to Seismic Load by Using Nonlinear System Models.
Trommsdorff, Molecular deformations of halogeno-mesitylenes in the crystal: structure, methyl group rotational tunneling, and numerical modeling, Chem.
The density functional theory (DFT) is a popular method for the calculation of molecular structures, vibrational frequencies and energies of molecules.
The FMOs play an important role in the optical and electric properties, as well as in quantum chemistry and UV-Vis spectrum [14].
Bigdeli, Identification of the Response of a Controlled Building Structure Subjected to Seismic Load by Using Nonlinear System Models.
Trommsdorff, Molecular deformations of halogeno-mesitylenes in the crystal: structure, methyl group rotational tunneling, and numerical modeling, Chem.
Online since: June 2012
Authors: Xing Guo Yu, Zai Yong Zhang, Xiao Feng Yang, Qun Hu Xue
Introduction
The lignin sulphonate is sulfonation product of lignin, and its molecule has various functional groups like methoxy group, hydroxyl groups (phenol hydroxyl and alcohol hydroxyl), double bond, sulfonic acid group, and ether bond, which have modified reactions with many substances, mainly oxidation of the oxidant, complexation of the metallic ions, the sulfonation of sulfonating agent, and condensation or graft copolymerization of formaldenyde[1].The lignin sulphonate is sub-global three-dimensional network structure body composed of about 50 phenylepropane units.The central part is unsulfonated original lignin three-dimensional network molecular structure.
In recent years, R.J.A.Gosselink, et al.[2,3] further researched the connection modes of lignin sulphonate molecules, and considered that its structure in solution was based on topological structure and conformation of its polymer chain, and there existed ruleless branched chains and the characteristics of branched macromolecule electrolyte decided that its thermodynamics flexibility belonged to medium degree rigidity bond polymer.
However the reports on the preparation of high water absorption and retention material with lignin sulphonate are few because of complex molecular structure, difficult purification, and hard control on reaction process[5].
When the addition of initiator K2S2O8 is low, the active center of polymer reaction is small, the polymerization speed is low, the polymer does not form three-dimensional network structure and shows water solubility in macrocosm, so the liquid absorption rate is low.
Chemistry. 2001,(8):470-477 [4] Jiang Tingda.Lignin[M].BeiJing: Chemical Industry Press.2001:117-155 [5]Chen R L, Kokta B V, Daneault C,et al.
In recent years, R.J.A.Gosselink, et al.[2,3] further researched the connection modes of lignin sulphonate molecules, and considered that its structure in solution was based on topological structure and conformation of its polymer chain, and there existed ruleless branched chains and the characteristics of branched macromolecule electrolyte decided that its thermodynamics flexibility belonged to medium degree rigidity bond polymer.
However the reports on the preparation of high water absorption and retention material with lignin sulphonate are few because of complex molecular structure, difficult purification, and hard control on reaction process[5].
When the addition of initiator K2S2O8 is low, the active center of polymer reaction is small, the polymerization speed is low, the polymer does not form three-dimensional network structure and shows water solubility in macrocosm, so the liquid absorption rate is low.
Chemistry. 2001,(8):470-477 [4] Jiang Tingda.Lignin[M].BeiJing: Chemical Industry Press.2001:117-155 [5]Chen R L, Kokta B V, Daneault C,et al.
Online since: July 2015
Authors: Mohd Zainizan Sahdan, Che Ani Norhidayah, Siti Nooraya Mohd Tawil, Nurul Fadzilah Ab Rasid
The FESEM studies show that when the Gd concentration was increased, the structures of the films are porous and the size of nanoparticles eventually became smaller cluster grains.
The AFM result revealed that Gd concentration which is 1% and 8% has a quite smooth with fine structure and uniform grains.
Bahadur, et al., "Nano-structured ZnO films by sol-gel process," Indian Journal of Pure and Applied Physics, vol. 45, p. 395, 2007
Wang, et al., "Effect of preheating and annealing temperatures on quality characteristics of ZnO thin film prepared by sol–gel method," Materials Chemistry and Physics, vol. 97, pp. 219-225, 2006
Volmer, "The Influence of Doping with Transition Metal Ions on the Structure and Magnetic Properties of Zinc Oxide Thin Films," The Scientific World Journal, vol. 2014, 2014
The AFM result revealed that Gd concentration which is 1% and 8% has a quite smooth with fine structure and uniform grains.
Bahadur, et al., "Nano-structured ZnO films by sol-gel process," Indian Journal of Pure and Applied Physics, vol. 45, p. 395, 2007
Wang, et al., "Effect of preheating and annealing temperatures on quality characteristics of ZnO thin film prepared by sol–gel method," Materials Chemistry and Physics, vol. 97, pp. 219-225, 2006
Volmer, "The Influence of Doping with Transition Metal Ions on the Structure and Magnetic Properties of Zinc Oxide Thin Films," The Scientific World Journal, vol. 2014, 2014