Epoxy/amine‐functionalized short‐length vapor‐grown carbon nanofiber composites

Short length vapor‐grown carbon nanofibers (VGCNFs) were functionalized with 4‐aminobenzoic acid in polyphosphoric acid/phosphorous phentoxide medium via “direct” Friedel‐Crafts acylation reaction to afford aminobenzoyl‐functionalized VGCNFs (AF‐VGCNFs). The AF‐VGCNFs as a cocuring agent were mixed with epoxy resin by simple mechanical stirring in methanol which was added to help efficient mixing. After evaporation of methanol, 4,4′‐methylenedianiline as a curing agent was added to the mixture, which was then cured at elevated temperatures. The resultant composites displayed uniform dispersion of AF‐VGCNFs into cured epoxy matrix. During curing process, the amine functionalities on AF‐VGCNF together with 4,4′‐methylenedianiline were expected to be involved in covalent attachment to the epoxy resin. As a result, both tensile modulus and strength of the composites were improved when compared with those of pure epoxy resin. Thus, the AF‐VGCNFs play a role as an outstanding functional additive, which could resolve both dispersion and interfacial adhesion issues at the same time by functionalization of VGCNFs and covalent bonding between the additive and matrix, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7473–7482, 2008     

Development of an automatic phase-contrast microscopic system capable of determining the microbial density and distribution inside an immobilized carrier.

The cell-immobilization technique is used for the physical and chemical fixation of cells onto a solid support in order to increase their stability and capacity of substrate uptake. However, there is no apparatus to observe the microbial community's structure inside cell immobilizing polymeric carrier. In order to satisfy the demand of monitoring for the microbial distribution inside the carrier, we developed an automatic phase contrast microscopic monitoring system capable of determining the microbial density and distribution inside a cell-entrapped carrier automatically.     

Application of NAA to air particulate matter collected at thirteen sampling sites in eight Asian countries: A collaborative study

Air particulate matter (APM) samples (PM_2.5 and PM_10–2.5) were collected at 13 sampling points in 8 Asian countries and their chemical compositions were determined by using neutron activation analysis (NAA) with the k ₀-standardization method in addition to conventional comparative method of NAA. Analytical data showed that mass concentration and elemental composition of the APM collected are variable in terms of time and space, and are related to the characteristics of the sampling sites concerned. NAA was proved to be highly effective for the regional characterization of APM in chemical composition.     

Organic solvent dispersion of poly(3,4‐ethylenedioxythiophene) with the use of polymeric ionic liquid

A nonaqueous dispersion of poly(3,4‐ethylenedioxythiophene) (PEDOT) was prepared with the use of polymeric ionic liquid (PIL) as a polymerization template and phase transfer medium. A detailed investigation was performed to understand the role of PIL in the course of polymerization and phase transfer reaction. On the basis of our findings from X‐ray photoelectric spectroscopy (XPS), we propose a mechanism by which the PIL leads to the nanostructured PEDOT colloids in various organic solvents and thus facilitating smoother surface morphologies of the PEDOT‐PIL films. In addition, the enhancement of charge transport was observed for PEDOT‐PIL complex when compared with PEDOT without PIL. Raman spectroscopy indicates that there is a reduced interaction between the charge carriers on the PEDOT and the counter ions bound to PIL, thus promoting charge carrier hopping rates. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6872–6879, 2008     

Pressure dependence of the elastic moduli of glasses in the K2OSiO2 system

The elastic moduli and their variation with pressure have been determined for three glass compositions in the K₂OSiO₂ glass system. The results may be summarized:

     

986.

Effect of bulk resistivity,annealing temperature and illumination on oxygen sorption on CdSe surfaces     

M.F. Chung  H.E. Fransworth 《Surface science》1971

The bulk resistivity, annealing temperature and photo-illumination were found to have large effects on the oxygen sorption of the Cd (0001) surfaces of CdSe. For the higher resistivity surfaces, annealing at temperatures below ~ 400°C, no oxygen adsorption was detected. However, if the surfaces were annealed at temperatures above ~ 500°C, a significant amount of oxygen adsorption was subsequently detected at room temperature in darkness. This adsorbed oxygen could be partially desorbed by visible light and almost completely desorbed by UV light. On the other hand, surfaces of very low resistivities were so much more reactive to oxygen that appreciable oxygen adsorption in darkness was detected. This oxygen adsorption was always enhanced by illumination with UV or visible light. Annealing at ~ 550 °C had no significant effect on this photo-adsorptive behaviour. However, annealing at temperatures ~ 500–550°C decreased the diffraction intensity. Based on mass spectrometer analysis, the decrease in diffraction intensity was interpreted as due to diffusion of excess Cd to the surface. The oxygen sorption behaviours of all the surfaces investigated were adequately explained by the existing theories based on charge transfer between the surfaces and the adsorbed oxygen.     

987.

Optimization of a peroxyoxalate chemiluminescence detection system for the liquid chromatographic determination of fluorescent compounds     

G. J. de Jong  N. Lammers  F. J. Spruit  U. A. Th. Brinkman  R. W. Frei 《Chromatographia》1984,18(3):129-133

Summary A peroxyoxalate chemiluminescence detection system for liquid chromatography is described. The excitation of fluorophores is generated by the reaction of bis-(2,4,6-trichlorophenyl)oxalate or bis(2,4-dinitrophenyl)oxalate and hydrogen peroxide, which are added to the column effluent. The influence of the solvents and the concentrations of the reagents have been investigated. The influence of the flow cell volume on sensitivity and on band broadening have also been studied and a chemical band narrowing effect has been observed. Different types of apparatus have been compared for detection of the emitted light. The system has been used for the detection of the dansyl derivative of a drug with a secondary amine functional group in serum samples. The detection limits are in the 1–10pg range.     

988.

Thermal degenerate rearramement of 1,2-dimethylenecyclobutane iron tricarbonyl     

Joseph J. Gajewski  Chung Nan Shih 《Tetrahedron letters》1973,14(40):3959-3962

Vapor phase pyrolysis of $\text{bis}$-1,2-(dideuteriomethylene) cyclobutane iron tricarbonyl at 170° resulted in hydrogen scrambling. Degradation of the rearrangement product indicated that either one exomethylene group was exchanging with one ring methylene or hydrogens were being reversibly transferred from the ring carbons to the exocyclic ones. Mechanisms that would explain either possibility involve the intermediacy of a sigma bonded iron with a π-allyl ligand.     

989.

A comparative study of two cavities for generating a microwave induced plasma in helium or argon as a detector in gas chromatography     

H.A. Dingjan  H.J. de Jong 《Spectrochimica Acta Part B: Atomic Spectroscopy》1981,36(4):325-331

In the microwave induced plasma (MIP) detector both $\text{1}\text{4}$λ-Evenson and Beenakker cavities are used. The last one also operates at atmospheric pressure. Both cavities are investigated with some simple alkanes. In the gas chromatographical system helium and argon are used as carrier gas. Measuring the C emission line, the Beenakker cavity with argon shows the greatest sensitivity, the best detection limit (0.2 ng C/s) and a good linear dynamic range (> 800). The best detection limit for H emission is found at use of the Beenakker cavity with helium (0.13 ng $\text{H}\text{s}$). The results of measuring the H emission line using the Beenakker cavity with argon are poor. It was further shown that, although it is in principle possible to determine a ratio formula or molecular formula with the aid of a reference compound, the results are inadequate for ‘unknown’ compounds.     

990.

The reactions ^50,52Cr(d, ⁶Li) ^46,48Ti at E_d = 651 MeV     

M.G. Betigeri  W. Chung  A. Djaloeis  W. Oelert  P. Turek 《Nuclear Physics A》1981,363(1):35-44

The ^50,52Cr(d, ⁶Li) ^46,48Ti reactions have been studied at E_d = 65 MeV bombarding energy. Angular distributions of outgoing Li particles were measured for final states in ^46,48Ti nuclei from 15° to 50° (lab). These were compared with zero-range and finite-range DWBA calculations in an α-cluster pick-up approximation to obtain relative α-spectroscopic factors.     

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Property/Composition	0.15K2O–0.85SiO2	0.25K2O–0.75SiO2	0.33K2O–0.67SiO2
Shear modulus $\text{G(}\text{kb}\text{)}$	266	241	231
Bulk modulus $\text{K}{}_{\mathrm{<mtext>s</mtext>}}\text{(}\text{kb}\text{)}$	310	283	273
Young's modulus $\text{E(}\text{kb}\text{)}$	620	564	540
($\text{?K}{}_{\mathrm{<mtext>s</mtext>}}\text{/?P)}{}_{\mathrm{<mtext>500\; </mtext><mtext>K</mtext>}}$	?5.1	?4.4	?3.9
($\text{?G/?P)}{}_{\mathrm{<mtext>500\; </mtext><mtext>K</mtext>}}$	?2.8	?2.6	?2.5
Poisson's ratio σ	0.167	0.168	0.170
($\text{?σ/?P) (}\text{x}\text{10}{}^{\mathrm{?3}}$)
(kb?1)	?1.5	?1.2	?0.95

Effect of bulk resistivity,annealing temperature and illumination on oxygen sorption on CdSe surfaces

The bulk resistivity, annealing temperature and photo-illumination were found to have large effects on the oxygen sorption of the Cd (0001) surfaces of CdSe. For the higher resistivity surfaces, annealing at temperatures below ~ 400°C, no oxygen adsorption was detected. However, if the surfaces were annealed at temperatures above ~ 500°C, a significant amount of oxygen adsorption was subsequently detected at room temperature in darkness. This adsorbed oxygen could be partially desorbed by visible light and almost completely desorbed by UV light. On the other hand, surfaces of very low resistivities were so much more reactive to oxygen that appreciable oxygen adsorption in darkness was detected. This oxygen adsorption was always enhanced by illumination with UV or visible light. Annealing at ~ 550 °C had no significant effect on this photo-adsorptive behaviour. However, annealing at temperatures ~ 500–550°C decreased the diffraction intensity. Based on mass spectrometer analysis, the decrease in diffraction intensity was interpreted as due to diffusion of excess Cd to the surface. The oxygen sorption behaviours of all the surfaces investigated were adequately explained by the existing theories based on charge transfer between the surfaces and the adsorbed oxygen.     

Optimization of a peroxyoxalate chemiluminescence detection system for the liquid chromatographic determination of fluorescent compounds

Summary A peroxyoxalate chemiluminescence detection system for liquid chromatography is described. The excitation of fluorophores is generated by the reaction of bis-(2,4,6-trichlorophenyl)oxalate or bis(2,4-dinitrophenyl)oxalate and hydrogen peroxide, which are added to the column effluent. The influence of the solvents and the concentrations of the reagents have been investigated. The influence of the flow cell volume on sensitivity and on band broadening have also been studied and a chemical band narrowing effect has been observed. Different types of apparatus have been compared for detection of the emitted light. The system has been used for the detection of the dansyl derivative of a drug with a secondary amine functional group in serum samples. The detection limits are in the 1–10pg range.     

Thermal degenerate rearramement of 1,2-dimethylenecyclobutane iron tricarbonyl

Vapor phase pyrolysis of $\text{bis}$-1,2-(dideuteriomethylene) cyclobutane iron tricarbonyl at 170° resulted in hydrogen scrambling. Degradation of the rearrangement product indicated that either one exomethylene group was exchanging with one ring methylene or hydrogens were being reversibly transferred from the ring carbons to the exocyclic ones. Mechanisms that would explain either possibility involve the intermediacy of a sigma bonded iron with a π-allyl ligand.     

A comparative study of two cavities for generating a microwave induced plasma in helium or argon as a detector in gas chromatography

In the microwave induced plasma (MIP) detector both $\text{1}\text{4}$λ-Evenson and Beenakker cavities are used. The last one also operates at atmospheric pressure. Both cavities are investigated with some simple alkanes. In the gas chromatographical system helium and argon are used as carrier gas. Measuring the C emission line, the Beenakker cavity with argon shows the greatest sensitivity, the best detection limit (0.2 ng C/s) and a good linear dynamic range (> 800). The best detection limit for H emission is found at use of the Beenakker cavity with helium (0.13 ng $\text{H}\text{s}$). The results of measuring the H emission line using the Beenakker cavity with argon are poor. It was further shown that, although it is in principle possible to determine a ratio formula or molecular formula with the aid of a reference compound, the results are inadequate for ‘unknown’ compounds.     

The reactions 50,52Cr(d, 6Li) 46,48Ti at Ed = 651 MeV

The ^50,52Cr(d, ⁶Li) ^46,48Ti reactions have been studied at E_d = 65 MeV bombarding energy. Angular distributions of outgoing Li particles were measured for final states in ^46,48Ti nuclei from 15° to 50° (lab). These were compared with zero-range and finite-range DWBA calculations in an α-cluster pick-up approximation to obtain relative α-spectroscopic factors.