Tạp chí của Viện Hàn lâm Khoa học và Công nghệ Việt Nam
Viện Khoa Học và Công Nghệ Việt Nam
Study of relationship between electronic structure and corrosion inhibitor efficency of some 2-hydroxy-4-methylacetophenone benzoyl hydrazone compounds
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Some 2-hydroxy-4-methylacetophenone benzoyl hydrazone compounds have been studied by the inhibition of copper corrosion in 3M nitric acid solution. The structure of some 2-hydroxy-4methylacetophenone benzoyl hydrazone compounds were caculated by using the AM1 method of the quantum chemical program HyperChem 7.0. Results of the above calculation are coordinated with inhibitor efficiency (P) that is determined by experiment and both are applied to Statgraphics 4.1 software to carry out linear regression.
Preparation some l-n-alkyl-3-metbylimidazolium tetrafluoroborate in green chemistry conditions.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> In this paper we described the preparation of some I -n-alkyl-3-smethylimidazoiium tetrofluoroborates ([Cnmim]BF4 with Cn is ethyl, n-butyl, n-hexyl, n-octyl respectively) in Green Chemistry conditions. All starting materials were used in stoichiometric quantities; the reactions were activated by microwave or ultrasound in solventless media. Firstly, alkylimidazolium bromides were prepared from the N-alkylation of N-methylimidazole with a n-alkyl bromide corresponding. After that, tetrafluoroborate furnished a metathesis with bromide to give the final products. Comparing with conventional heating, the obtained yield was higher and the reaction time was shorter under microwave irradiation.
Preparation of composite materials based on unsaturated polyester resin reinforced by Neuhoitzeuza fiber treated by plasma method.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> After extracting by mechanical (by hand) and machine methods, Neohouzeaua fiber was treated by air plasma at atmospheric pressure with conditions of power 100W, frequency of 17 kHz and different treatment times (from 1 min to 7 min). SE M analyses showed that the fiber surface become rougher after plasma treatment because of the effect ofplasma bombardment and etching. The testing on tensile strength and the interfacial shear strength (lFSS) showed that at the optimal treatment time of 4 minutes: the tensile strength of neohouzeaua fiber increased 15.5 percent after air plasma treatment and treated Jiber have cleaner surface. IFSS of the treated fiber at 4 minutes increased 51.7% compared with untreated fiber. Unsaturated polyester (USP) resin composites reinforced by neohouzeaua fiber submitted to air plasma treatment and untreated and USP composites reinforced by hybrid neohouzeaualglass fiber mat were fabricated using a vacuum infusion process (VIP). Mechanical test, SEM and water absorption measurements of the composites have been investigated. These results reveal that atmospheric pressure air plasma treatment is an effective method 10 improve not only the performance of neohouzeaua fiber but also of UPS-neohouzeaua composites. With hybrid composites with ply-byply structure and the content ratio of neohouzeaualglass of 40/60 (by weight) the received materials has optimal properties, such as tensile, flexural and impact strengths improve 38.9%, 15.5% and 217.5% compare to PC-Neohouzeaua mat, respectively.
Preparation of colloidal gold nanoparticles by γ-irradiation method
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Gold nanoparticles were prepared by r-irradiation of HauCl4 aqueous solution using chitosan as stabilizer. The particles have a Plasmon absorption band with maximum wavelength in the range of 520 - 534 nm. The average size of gold nanoparticles observed by transmission electron microscope (TEM) was of 25.3; 23.4 and 16.4 nm for 0.5; 1.0 and 2.0% chitosan respectively. The effect of Au3+ concentration on the particle size and the stability of gold colloidal nanoparticles with storage time were also studied.
Triterpenes oleanan from Lantana camara L.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Three pentacyclic triterpenoids, Lantaden B (3), Icterogenin (4) and 3-oxo-25-methylhydroxy22β-[(Z)-2'-butenoyloxyl-olean-12-ene-28-oic acid (5) and two common steroids, β-sitosterol (I) and β-sitosterol 3-0-β-D-glucopyranoside (2) were isolated from the aerial parts of Lantana camara L. Structures of the triterpenoids were elucidated by spectroscopic methods.
Synthesis of nanosized V2O5 by the gel combustion method.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Vanadium pentoxide powder has been synthesised at low temperature (550oC) by the combustion of gel prepared from polyvinyl alcohol (PVA) and vanadium chlorid. The characterization of V205 powder is examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET (Brunaure-Emmet-Teller) measurements. Further thermal treatment at 400 - 60CPC in 1.5h yields the single phase V205 with average size < 50 nm. Its specific surface area is 23.50 m2/g for V205.
Mineralization; Electrochemical Fenton; Oxidation; Methyl red
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> To promote treatment efficiency, an efficient undivided electrochemical system using a Ppy (Cu1,5Mn1,504) composite film on graphite cathode with high production rate of hydrogen peroxide was applied to the electro-Fenton oxidation of a model azo dye, methyl red (MR). The influences of operating parameters including cathodic potential, Fe2+ concentration, and oxygen gas flow and initial methyl red concentration was investigated. At the conditions of cathode potential of -0.6 V versus SCE, Fe2+ concentration of 0.1 mM, a solution of methyl red of 1.85 mM could become transparent totally in 24 hours with a high current yield (200% for first one hour).
The nutrient release from mineral organic fertilizers on peat-based substrate. Part I - Single mineral nutrition
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> The adsorptions of nutrient N, P, K on the Ca Mau peat and Tay Ninh peat have been studied. The Ca Mau peat absorption capacities of nutrient cations (NH4+ and K+) are higher than Tay Ninh peat, but the adsorption of phosphate anions is less. The releases of N, P, and K nutrient from mineral organic fertilizers contented single mineral nutrition with different compositions have been investigated. The single mineral fertilizers composted with 8% mineral nutrient have higher slow-release effect. The colloidal humic system plays main part in phosphorus slow-release.
Selective oxidation of benzyl alcohol over perovskite catalyst containing - chromium supported on the mesoporous material.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]-->A perovskite containing-chromium supported on the mesoporous material was synthesized by hydrothermal method using hexadexyl trimethyl ammonium bromide. The solid was characterized by several techniques including X-ray diffraction, SEM, TEM. and Raman spectrocopy. The obtained material has been tested for the liquid oxidation of benzyl alcohol under milder conditions. A rather high selectivity to benzaldehyde is formed
Synthesize of lignosulfonate from recovery lignin of soda pulping mill
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if !mso]> <![endif]--><!--[if gte mso 10]> <![endif]--> In the black liquor of Pulp and Paper Mills, that produces pulp by soda method, contain a large amount of organic compound, especially high content of lignin. Lignin has a lot of important applications in Industry. Lignosulfonate, which is a important deriver of lignin. has many advantages as a surfactant in many fields, for example, in pharmaceutics and pesticide Technology; Petroleum Industry; Printing Industry; Construction; Agriculture... In Vietnam, every year some Pulp and Paper Mills eliminate a large amount of black liquor but they haven't lignin recovery line. This causes the pollution of environment seriously. Therefore, these black liquor are the available resources to produce lignosulfonate. Finding out the process to separate lignin from black liquor and processing it become trade products such as lignosulfonate not only brings the effect economy but also reduces the influence ofpolluted black liquor on environment.
Grafting acrylic acid onto chitin by irradiadon technology for adsorption of Zn2+ and Cu2+ ions
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Partially deacetylated chitin (PD/chitin) was modified by irradiation grafting with acrylic acid (AAc) for various concentrations of 5,10,15,20% at dose up to16 kGy and dose rate of 1.6 kGy/h. The dependence of the grafting rate (Vg) onto monomer concentration (M) was determined to be Vg = k[M]1.09. Equilibrium isotherms for the adsorption of heavy metal ions (Zn2+, Cu2+) onto grafted PD/chitin have been also investigated
Synthesis of anodic electrodeposition coating based on polyester resin modified by Vietnam’s tung oil and soyabean oil
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if !mso]> <![endif]--><!--[if gte mso 10]> <![endif]--> The results of the synthesis of hydrosoluble polyester used for anodic electrodeposition coating from Viet Nams tung and soybean oils are represented in this article. The oil fatty acids characteristic indexes were determined by gas chromatography method with the use of mass spectrophotometer as detector. The molecular weights of polyester were determined by gel permiation chromatography method. The formation process of polyester was studied by infrared spectrum. The changes in viscosity and conductivity of polyester solution in water with change in pH value were studied. The distribution of colloid particles size in solution of pH = 8.2 was determined.
Molecular dynamics calculation of the E226Q mutant effect on the properties of CADPR-CD38 complexes
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Using GROMACS software a molecular dynamics simulation of the cADPR-CD38 (A) and cADPR-E226Q mutant (B) complexes has been implemented. The calculation results shown that there are no obvious differences between thermodynamic properties of these complexes. However, the variations of the molecular structure and kinetic properties as well could explain the essential elimination of catalytic activities by Glu226 's mutation. In A the cADPR could embed deep toward the bottom of the active site pocket making salt bridge with a catalytic residue Glu146, while there is no such a saltbridge in B. The averaged hydrogen bond number between cADPR and protein in B is higher than in A and on the contrary, the self-diffusion coefficient of cADPR in B is about two times smaller than in A.
Bioactive compounds in Scorpion venom Heterometrus laoticus
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> The scorpion Heterometrus laoticus, family Scorpionidae, are wide distributed in the west of the South of Vietnam. In the traditional medicine the alcohol extract of these scorpions is used as analgesic for muscle and bone pain. However, the venom of Vietnamese H. laoticus has not been studied untill now, so we carried out this work. Venom was collected from H. laoticus scorpions distribuding in the An Giang province. The crude venom of H. laoticus scorpions was separated into ten fractions by column chromatogaphy on Bio-Gel P 10. These fractions have different physic-chemical and biological properties. Tests on mice showed that six of these fractions are toxic. The most toxic fractions have molecular weight in range of 3-5 kDa and 6-8 kDa, that similar to neurotoxins isolated from scorpions,family Buthudae. Beside of the neurotoxins, in the H. laoticus venom there is toxins causing bleeding when inject them into mice. The crude venom of H. laoticus scorpion has activities against various kinds of microorganisms such as Staphylococcus aureus, Bacillus subtilus and Escherichia coli. This venom can be used in further to isolate the toxins and anti-bacterium compounds
The research on synthesis of the semiconductive polymer base on ferrocene
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> The semiconducting polymer based on ferrocene has been synthesized by the poly-condensational reaction of ferrocene with benzaldehyde. The conditions of the reaction include the molar ratio of ferrocene:benzaldehyde as 1:1.3 and the catalytic p-toluene sulfonic acid make linear- soluble polymer. The external conditional reaction as duration of reaction: 60 minutes, temperature: 106±2°C make polymer has Mw: 900 - 1000 dvC and electric conductivity of polymer is σ: 10-7S/m
Synthesis of lignosulfonate surfactants from waste water of kraft pulping process, used in the pesticide formulation
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Lignosulfonates have been used as surfactants in many field of industry. Based on the survey of several main lignosulfonate synthesis methods, the ethylsulfonation of lignin, obtained from black liquor, a waste water from kraft pulping proces was investigated. The mixture offormalin and sodium sulfite was selected and used as methylsulfonation agent. The suitable conditions for this reaction were examined and optimized (molar ratio of reactants, time of reaction, amount of sulfonation agent...). The products were identified and characterized by Infrared Spectroscopy and sulfonation degree measuring (through sulphur element determination in the product). The products are successfully used as multifunctional surfactants in the formulation of two commercialfungicides: Copper oxychloride 30WP and Sulphur 80 WDG.
Synthesis of l%Ti02-x%NiO (x = 1, 3, 5, 7, 10) catalysts used for hydrocarbon Oxidation
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Large-pore three-dimensional (3D) mesoporous silicas are among the most interesting mesoporous materials discovered in recent years, and they have attracted much attention for potential applications to make the supports for polyfunctional catalysts. In this report, the synthesis of the mesoporous silica with a bicontinuous cubic structure of la3d symmetry by using a commercially available triblock copolymer (EO20P070EO20)-butanol mixture for the structure direction in aqueous solution was investigated. Then, cubic la3d mesoporous silica molecular sieves were modified with Ni-Ti mixed oxide and their structural characteristics were determined by X-ray diffraction, nitrogen physical sorption, TEM and their catalytic activity in gas phase oxidation reaction of LPG was studied.
Some results of waterborne paint for protection of steel reinforced concrete in marine and maritime environment
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> This article is about our research on two different kinds of waterborne paint: acrylic and epoxy paints ideally for making anticorrosive coatings of steel reinforced concrete in marine and maritime environment. Using water as the main solvent, these paints with low organic solvent are normally non odor. Our empirical tests show that they fulfilled all requirements of 22TCN 235-97 and TCVN 6934:2001, the Vietnamese technical standards governing building materials for protection of concrete or steel reinforced concrete in the maritime climate area.
Mechanical properties of sisal/glass fiber mat reinforced epoxy der-331 resin hybrid composites
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Sisal fiber is an effective reinforcement for epoxy resin. Mechanical properties of a sisal fiber mat reinforced epoxy resin composite are higher in comparison with those of epoxy resin, especially in impact strength, which is 369% higher. The effect of alkali treatment of sisal fiber on the interfacial shear strength (IFSS) and mechanical properties of sisal fiber mat reinforced epoxy DER-331 resin composites were studied. It has shown that average IFSS is 94% higher, tensile strength and flexural strength of composite are 72% and 31% higher respectively in comparison with those of untreated fibers. In order to improve mechanical properties of composite material, sisal fiber mat was replaced partly by glass fiber mat. Owing to the superior properties of glass fibers, the mechanical properties of the hybrid composites increase with the increasing of weight fraction of glass fibers. The observation has shown that optimum glass fiber mat loadings for the hybrid composite was 50 wt.%. Water absorption of the hybrid composite was reduced from 8.5 to 2.4%) in comparison with non-hybridized sisal fiber mat reinforced epoxy resin composite. Scanning electron microscopic studies were carried out to study the fiber-matrix adhesion.
Preparation, structure and properties of silane modified silica/natural rubber nanocomposite. Part I - Forming mechanism of nanocomposite.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Natural rubber/silica nanocomposite were prepared by mixing aqueous suspension of bis(3-triethoxysilylpropyl) tetrasunfit silane (TESPT) modified silica with Hevea Brasilienis latex using a pulverisette type mixer. Dispersion of the modified silica was characterized by laser scattering particle size distribution analyzer and SEM. The results showed that silica in suspension with statistical parameters: median 3.5 (µm); mean 3.8 (µm); variance 4 (µm2); standard deviation 2 (µm) is necessary to make nanocomposite with size distribution in range of 30 -100
Degradation of 2,4,6-trinitrotoluene in solid waste using microorganisms in two stages
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> A method for biodegrading 2,4,6-trinitrotoliiene (TNT) as contaminant in solid waste by treatment of the contaminated waste under anaerobic using natural microorganisms is disclosed. Dry solid waste was first converted into a fluid medium by addition of water with a source of carbohydrate such as starch, potato processing waste, sewage sludge... The mixture was maintained in anaerobic condition and natural microorganisms fermented the carbohydrate and exhausted the oxygen in the fluid medium thereby rendering the slurry anaerobic which lowered the redox potential of the environment and promoted degradation of TNT in the followed stage. Anaerobic conditions were preferably determined via a potentiometric measurement, where a redox potential of -200 mV or less indicated strict anaerobic conditions. In the subsequent anaerobic stage, an inoculum of a mixed population of anaerobic microorganisms completed the mineralization of TNT, using the remaining carbohydrate as a carbon and energy source. Microbial activity can assist degradation of organic contaminants either directly by enzyme production, or indirectly, by maintaining the reduction conditions of the environment and thereby enhancing the inorganic and biochemical mechanisms. Bench scale experiment was conducted to assess the rate and extent of TNT biodegradation. Results indicated that after 6 to 7 weeks incubation the concentration of TNT reduced greater than 95% fiom 277 mg.kg-1 at the initial to below 13 mg.kg-1.
Characterization and phenomena happened during the synthesis of AuY catalyst and its activity in the complete oxidation of toluene
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Gold catalysts supported on zeolite Y were prepared by ion-exchange. The catalysts were characterized by XRD, TGA/DTA, IR, SEM and TEM. It is shown that gold crystallites are deposited on framework of zeolit and zeolit structure is not deformed afier being dried at 110oC and calcined at 400oC. The average size of the gold particles depends on the gold content of the support. The complete oxidation of toluen in air was carried out over AiiY. Catalytic activity was tested at temperature of 250 to 400oC. Toluene was converted completely to COx. No organic byproducts were detected. Catalytic activity depends on temperature, gold content and time on stream.
The examination of factors affecting on the particle size nickel oxide synthesized by auto gel combustion process
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Nickel oxide with tiny particle sizes is formed by auto combustion process of nickel nitrates and polyvinyl alcohol (PVA) gel. Factors affecting on particle sizes of nickel oxide including pH and temperature of gel formation, mole ratio of concentration of nickel and the concentration of polyvinyl alcohol used to produce gel were examined. The particle size distribution of nickel oxide was measured by particles analyzer. The powders morphology was observed by Transmission Electron Microscopy (TEM).
Characterization of Fe-doped TiO2 photocatalysts, prepared by sol-gel method
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Thin layers of pure TiO2 and TiO2 doped by different amounts of Fe203 liave been prepared by sol-gel metliod with tetraisopropyl ortliotitanate and Fe(NO3)3. Physicochemical properties of the catalysts were studied by the metliods of BET Adsorption, X-ray Diffraction (XRD), FE-SEM, as well as Raman, IR and UV-Vis spectroscopies. Photocatalytic activity of the obtained materials was investigated in tlie reaction of complete oxidation of p-xylene in gas phase under the radiation of UV (l = 365 nm) and Blue LED (l = 470 nm) lamps. It has been found that particle's size of all the samples is distributed in the range of 20-30 nm. The content of rutile phase in Fe-doped TiO2 samples varied from 6.8 to 41.8% depending on the Fe content. Iron oxide doped into Ti02 enables to move tlie photon absorbing zone of TiO2 from UV toward visible wave lengths as well as to reduce its band gap energy from 3.2 eV to 2.67 eV. Photocatalytic activities of tlie TiO2 samples promoted by Fe3+ have been found to be higher than those of pure TiO2.
Study on the structure of a cytotoxic fucoidan from brown seaweed sargassum swartzii by tandem mass spectrometry
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> We reported a study of the structure of cytotoxic fucoidan fraction extracted from brown seaweed Sargassum swartzii by using NMR and tandem mass spectrometry in combination with a Pascal software program. Fucoidan F-20 is composed mainly of fucose, accompanied by other monosaccharids (mostly Gal, but also Glc, Rha and Xyl), and significant amount of uronic acids and sulfate. MSIMS analysis showed the cytotoxic fucoidan F-20 has linear sequences of hexose-disulfated fucose-sulfated fucose-hexose. The fucoidan structure is chracterized by the branch of two glucuronic acid units linked to the hexose unit and fucose to the sulfated fucose.
Unimolecular rate theory test in thermal systems.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if !mso]> <![endif]--><!--[if gte mso 10]> <![endif]--> The limiting high-pressure unimolecular rate constant k∞ in thermal systems can be considered as the Laplace transform of the detailed rate constant, or specific dissociation probability, k(E) (E = internal energy). If k∞ is known from experiment as a function of temperature in the form k∞=A∞exp(-E∞/kT), k(E) can be obtained by inversion. Using one actual examples, the inversion procedure is exploited to show that k∞ contains sufficient information for a test of unimolecular rate theory that requires only the knowledge of the molecular properties of the reactant but not those of the transition state. Since there are no parameters to adjust, this test, in a thermal system, is therefore more significant than the more usual speculative curve-fitting.
Synthesis and active catalyst of colbatetrasulfophtaloeyanine supported on Ti02 carrier
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]-->Cobalt-tetrasulfophthalocyanine supported on TiO2 carrier has been synthesized. Investigate of oxidising sulfide by using the supported catalyst was carried out as well. The result shows that the activity of the catalyst is highest under visible light irradiation and is carried out at the pH of 10
Synthesis of nickel aluminates spinel on silica oxide
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Nickel aluminates spinel NiAl204 in the silica glassy matrix was prepared through insitu sol-gel reaction. The influence of temperature and the molar ratio of metals to Si on the formation of the spinel were investigated. The DTA, TGA and XRD analyses showed that NiAl204/Si02 was completely produced at 800oC. The surface properties of the synthesized spinel were identified by nitrogen adsorption-desorption method
Preparation, characteristics of structure and properties of the ethylene-vinyl-aeetate copolymer/organic montmoriilonite composites
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> Ethylene-vinyl acetate copolymer (EVA)/organic montmorillonite (O-MMT) composites were prepared via direct melt mixing EVA containing vinyl acetate (VA) of 9% with 0-MMT in an intermixed Haake at 160oC. The relative melt viscosity of EVA and EVA/O-MMT composites were evaluated according to changing of torque of the materials during melt mixing process. Their structures were investigated with X-ray diffiaction (XRD) and scanning electron microscopy (SEM). The electrical parameters of composites were measured by the dielectric loss measuring set. The results showed that the torques of EVA/O-MMT composites increase with rising O-MMT content. The XRD patterns indicated that E\'A chains could be intercalated into the mterlayer gallery of O-MMT and interacted with O-MMT, leading to expansion of the interlayer space, but not yet destroyed their layered struclnres. The SEM photographs proved the existence of both nanostructure and microstructure in the EVA/O-MMT composites.
Preparation of barium titanate nanosized by hydrothermal synthesis method.
<!--[if gte mso 9]><xml> Normal 0 false false false MicrosoftInternetExplorer4 </xml><![endif]--><!--[if gte mso 9]><xml> </xml><![endif]--><!--[if gte mso 10]> <![endif]--> The BaTiO3 powders were synthetized by the hydrothermal method in the alkaline solution using the TiCl3 and BaCl2 like precursors. The Ba/Ti initial ratios effect on the formation of BaTiO3 phase was investigeted versus time (at 150°C). The results showed that BaTiO3 powders have right stoichiometric (approximate 1), homogeneous morphology and grain sizes are in the range of 80 - 100 nm