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1995 Volume 12 Issue 4
1995, 12(4): 1-6
Abstract:
The recent advances in developments and applications of laser-scanning photoelec-trochemical microscopy techniques have been reviewed,incltiding experimental methods and their uses in the studv of metal-oxide electrodes,surface lnodification of semiconductor elec-trode,photoelectrochemical corrosion and electrodeposition of photoelectrochemical-active materials.
The recent advances in developments and applications of laser-scanning photoelec-trochemical microscopy techniques have been reviewed,incltiding experimental methods and their uses in the studv of metal-oxide electrodes,surface lnodification of semiconductor elec-trode,photoelectrochemical corrosion and electrodeposition of photoelectrochemical-active materials.
1995, 12(4): 7-12
Abstract:
The synthesis of glycerin monoether of 4-[(p-nitrophenyl) azoxy] phenol which can form liquid crystalline phases is reported. The crosslinking reaction of glycerin mo-noether of 4-[(p-nitrophenyl) azoxy] phenol by biuret of hexamethylene diisocyanate has been studied by DSC and FTIR spectra. The orientation and stability of a poled and crosslinked polymer have been investigated by UV-Vis spectra. The orientation relaxation was not observed in 100 hours for the poled and crosslinked polymer after poling and crosslinking for 1h at 150℃.
The synthesis of glycerin monoether of 4-[(p-nitrophenyl) azoxy] phenol which can form liquid crystalline phases is reported. The crosslinking reaction of glycerin mo-noether of 4-[(p-nitrophenyl) azoxy] phenol by biuret of hexamethylene diisocyanate has been studied by DSC and FTIR spectra. The orientation and stability of a poled and crosslinked polymer have been investigated by UV-Vis spectra. The orientation relaxation was not observed in 100 hours for the poled and crosslinked polymer after poling and crosslinking for 1h at 150℃.
1995, 12(4): 13-17
Abstract:
The specific refractive index increments of a number of water soluble polymers in pure water were determined by quantitative size exclusion chromatography (SEC) equiped with a refractive index detector. The results obtained are identical with literature values de-termined by conventional static methods. For SEC with aqueous salt solution as eluent, whick is similar to a mixed solvei,system,the chromatographic separation process of the so-lute with surrounding solvent molecules is equivalent to dialysis process. Under the condi-tions of chromatographic apparatus equiped with and without SEC separation columns, from the measured refractive index response constants the refractive index increment under con-stant chemical potential νμ and under constant composition of the solvent νk of the polymers could be determined. For the neutral polymer,polyacrylamide in aqueous NaCl solution, νμ > νk, that indicates the preferential adsorption of salt molecules by polymer chain, while for the polyelectrolyte sodium polystyrene stilfonate, νμ < νk, i.e. the water molecules are prefer-entially adsorbed by polymer chain.
The specific refractive index increments of a number of water soluble polymers in pure water were determined by quantitative size exclusion chromatography (SEC) equiped with a refractive index detector. The results obtained are identical with literature values de-termined by conventional static methods. For SEC with aqueous salt solution as eluent, whick is similar to a mixed solvei,system,the chromatographic separation process of the so-lute with surrounding solvent molecules is equivalent to dialysis process. Under the condi-tions of chromatographic apparatus equiped with and without SEC separation columns, from the measured refractive index response constants the refractive index increment under con-stant chemical potential νμ and under constant composition of the solvent νk of the polymers could be determined. For the neutral polymer,polyacrylamide in aqueous NaCl solution, νμ > νk, that indicates the preferential adsorption of salt molecules by polymer chain, while for the polyelectrolyte sodium polystyrene stilfonate, νμ < νk, i.e. the water molecules are prefer-entially adsorbed by polymer chain.
1995, 12(4): 18-22
Abstract:
The surface properties of a series of segmented and graft copolymers and blends containing polydimethylsiloxane(PDMS) have been investigated by XPS. It is shown that enrichment of PDMS soft segments or molecules occurs on the surface of the segmented copolymers as well as on that of graft copolymers and blends. The order of degree of enrich-ment is as follows: blends > graft copolymers > segmented copolymerss, which is explained as a resuIt of the easiness of movement of the PDMS segments or molecules. Meanwhile, compatibility between the different components (or phases) of the copolymers or blends is of disadvantage to enrichment of PDMS on the surface.
The surface properties of a series of segmented and graft copolymers and blends containing polydimethylsiloxane(PDMS) have been investigated by XPS. It is shown that enrichment of PDMS soft segments or molecules occurs on the surface of the segmented copolymers as well as on that of graft copolymers and blends. The order of degree of enrich-ment is as follows: blends > graft copolymers > segmented copolymerss, which is explained as a resuIt of the easiness of movement of the PDMS segments or molecules. Meanwhile, compatibility between the different components (or phases) of the copolymers or blends is of disadvantage to enrichment of PDMS on the surface.
1995, 12(4): 23-26
Abstract:
The reductive stripping potentiometric analysis of lead in the presence of potassi-um ferrocyanide as reducing agent on platinum electrode has been investigated. The pretreat-ment of the electrode, processes of anodic preconcentration and subsquent analysis,and the interference of foreign ions were discussed. The linear range was 1×10-7 to 5×10-6 mol/L for lead.
The reductive stripping potentiometric analysis of lead in the presence of potassi-um ferrocyanide as reducing agent on platinum electrode has been investigated. The pretreat-ment of the electrode, processes of anodic preconcentration and subsquent analysis,and the interference of foreign ions were discussed. The linear range was 1×10-7 to 5×10-6 mol/L for lead.
1995, 12(4): 27-31
Abstract:
Blends of two liquid crystalline copolyesters (LCP:for LCP1 PET/PHB=40/60, for LCP2 PET/PHB=30/70) and its ternary blends containing nylon1010 as the matrix were studied by using DSC,POM,SEM and mechanical tests. The results indicated that the me-chanical properties of LCP blends were improved substantially and their melt viscosity and flow temperature could be modified by changing the composition of individual LCP so as to rnatch the "processing window" of the matrix in making in-situ composites. Neither a signifi-cant improvement in mechanical properties nor the melting and crystallization behavior of ny-lon1010 was observed after blending, which was explained in terms of poor miscibility and orientational deformation of LCP.
Blends of two liquid crystalline copolyesters (LCP:for LCP1 PET/PHB=40/60, for LCP2 PET/PHB=30/70) and its ternary blends containing nylon1010 as the matrix were studied by using DSC,POM,SEM and mechanical tests. The results indicated that the me-chanical properties of LCP blends were improved substantially and their melt viscosity and flow temperature could be modified by changing the composition of individual LCP so as to rnatch the "processing window" of the matrix in making in-situ composites. Neither a signifi-cant improvement in mechanical properties nor the melting and crystallization behavior of ny-lon1010 was observed after blending, which was explained in terms of poor miscibility and orientational deformation of LCP.
1995, 12(4): 32-35
Abstract:
The amorphous Fe-W deposit is passivated chemically and electrochemically in chromate solutions in order to form a passive film. Anodic polarization curves show that the pitting potential of passivation moves about 1.68V toward noble. Amorphous Fe-W deposits were corroded severelv within one hour in NaCl solution, but the passivated deposit exhibit-ed no change and maintained metal luster on the surface after one month of immersion.
The amorphous Fe-W deposit is passivated chemically and electrochemically in chromate solutions in order to form a passive film. Anodic polarization curves show that the pitting potential of passivation moves about 1.68V toward noble. Amorphous Fe-W deposits were corroded severelv within one hour in NaCl solution, but the passivated deposit exhibit-ed no change and maintained metal luster on the surface after one month of immersion.
1995, 12(4): 36-39
Abstract:
The enthalpy changes on mixing and reaction between synthetical MgO-27.56% MgCl2-H2O solution and azeotropic hydrochloric acid have been studied with a precise calorimeter. It is shown that the active magnesium oxide has different thermochemical be-havior in 27.56%MsCl2-H2O solution. When the concentration of MgO is ≤0.8914mmol (50mL solution) the molar enthalpy of MgO is almost identical small than when the concen-tration is higher. A mechanism for the reaction has been proposed in combination the results with that obtained in azeotropic hydrochloric acid-pH titration.
The enthalpy changes on mixing and reaction between synthetical MgO-27.56% MgCl2-H2O solution and azeotropic hydrochloric acid have been studied with a precise calorimeter. It is shown that the active magnesium oxide has different thermochemical be-havior in 27.56%MsCl2-H2O solution. When the concentration of MgO is ≤0.8914mmol (50mL solution) the molar enthalpy of MgO is almost identical small than when the concen-tration is higher. A mechanism for the reaction has been proposed in combination the results with that obtained in azeotropic hydrochloric acid-pH titration.
1995, 12(4): 40-42
Abstract:
The Modified NaZSM-5 zeolite: Fe-ZSM-5,MgZSM-5,and Fe-Mg-ZSM-5 zeo-lites have been tested as eatalyst in mononitration of toluene by mixed acid. The para substi-tuted nitrotoluene was found to be considerably increased. Some factors affecting o/p ratio have been investigated.
The Modified NaZSM-5 zeolite: Fe-ZSM-5,MgZSM-5,and Fe-Mg-ZSM-5 zeo-lites have been tested as eatalyst in mononitration of toluene by mixed acid. The para substi-tuted nitrotoluene was found to be considerably increased. Some factors affecting o/p ratio have been investigated.
1995, 12(4): 43-47
Abstract:
Eighteen title compounds were synthesized by phase transfer catalysis. The aver-age yields are over 90%. For the obtained flame retardants,their structures were identified by IR,NMR and elemental analysis,and their properties of the flame retardation and plasti-cization have also been investigated.
Eighteen title compounds were synthesized by phase transfer catalysis. The aver-age yields are over 90%. For the obtained flame retardants,their structures were identified by IR,NMR and elemental analysis,and their properties of the flame retardation and plasti-cization have also been investigated.
1995, 12(4): 48-51
Abstract:
The effect of polyacrylamide on rheology of petroleum stilfonate-butanol mixed micelle system has been studied. The results showed that the mixed micelle svstem was pseudoplastic fluid with a yield point,and had a shear thinning property in the presence of 7000ppm mineralized water. When polyacrylamide was added,the apparent viscosity of mixed system further increased, without change of flow pattem. These systems were ana-lyzed by using the power-law and Casson models. This particular behavior is attributed to the formation of polymer-micelle aggregates in the presence of mineralized water.
The effect of polyacrylamide on rheology of petroleum stilfonate-butanol mixed micelle system has been studied. The results showed that the mixed micelle svstem was pseudoplastic fluid with a yield point,and had a shear thinning property in the presence of 7000ppm mineralized water. When polyacrylamide was added,the apparent viscosity of mixed system further increased, without change of flow pattem. These systems were ana-lyzed by using the power-law and Casson models. This particular behavior is attributed to the formation of polymer-micelle aggregates in the presence of mineralized water.
1995, 12(4): 52-57
Abstract:
A nonuniform space-volume-grid system is generated by repeatedly dividing the solution layer next to the electrode surface. For outer limit of the ith grid it is simply ex-pressed as Xio=△Xβi-1. With a dividing factor β≥2 the generated space-volume grid is ex-panded by the factor of β for i > 2,however the volume ratio for the second and the first grid is only (β-1). The simulation accuracy and stability of the grid system for explicit-finite-difference algorithm are characterized by experiments of chronoamperometry and cyclic voltammetry experiments. The results demonstrate that the simulation is relatively stable and accurate enough for theoretical comparison at β=2. This system can even be operated for time-saving qualitative test at β values as large as 16.
A nonuniform space-volume-grid system is generated by repeatedly dividing the solution layer next to the electrode surface. For outer limit of the ith grid it is simply ex-pressed as Xio=△Xβi-1. With a dividing factor β≥2 the generated space-volume grid is ex-panded by the factor of β for i > 2,however the volume ratio for the second and the first grid is only (β-1). The simulation accuracy and stability of the grid system for explicit-finite-difference algorithm are characterized by experiments of chronoamperometry and cyclic voltammetry experiments. The results demonstrate that the simulation is relatively stable and accurate enough for theoretical comparison at β=2. This system can even be operated for time-saving qualitative test at β values as large as 16.
1995, 12(4): 58-61
Abstract:
The extraction mechanism of Th(Ⅳ) with bis(2,4,4-trimethylpentyl)phosphinic acid (HA) in n-octane from HCl medium with different ionic strength is studied. When the ionic strength of the aqueous phase is not controlled,the extraction equilibrium is Th4++Cl+3(HA)2(о)⇄ThClA3·(HA)3(о)+3H+. And when the ionic strength is 1.0mol/L, the extraction equilibrium is Th4++2Cl-+3(HA)2(о)⇄ThCl2A2·(HA)4(о)+2H+. The composition of the extracted complex determined by the saturation method is ThClA3. The effect of temperature on the extraction of Th(Ⅳ) indicates that it is an endothermal re-action. The stability constants and thermal mechanical functions of the extraction reaction are calculated. The IR and NMR spectra of the saturated complex are studied.
The extraction mechanism of Th(Ⅳ) with bis(2,4,4-trimethylpentyl)phosphinic acid (HA) in n-octane from HCl medium with different ionic strength is studied. When the ionic strength of the aqueous phase is not controlled,the extraction equilibrium is Th4++Cl+3(HA)2(о)⇄ThClA3·(HA)3(о)+3H+. And when the ionic strength is 1.0mol/L, the extraction equilibrium is Th4++2Cl-+3(HA)2(о)⇄ThCl2A2·(HA)4(о)+2H+. The composition of the extracted complex determined by the saturation method is ThClA3. The effect of temperature on the extraction of Th(Ⅳ) indicates that it is an endothermal re-action. The stability constants and thermal mechanical functions of the extraction reaction are calculated. The IR and NMR spectra of the saturated complex are studied.
1995, 12(4): 62-65
Abstract:
In this paper,ten new 1-substituted phenyl-4-hydrocarbyl thiosemicarbazides were perpared. Their strticture was identified by elemental analysis,IR,1H NMR and MS spectra. The preliminary biological activity studies indicate that all the compounds possess strong bactericidal action and bacteriostasis against Escherichia coli and Staphylococcus au-reus.
In this paper,ten new 1-substituted phenyl-4-hydrocarbyl thiosemicarbazides were perpared. Their strticture was identified by elemental analysis,IR,1H NMR and MS spectra. The preliminary biological activity studies indicate that all the compounds possess strong bactericidal action and bacteriostasis against Escherichia coli and Staphylococcus au-reus.
1995, 12(4): 66-69
Abstract:
Five series of polyepichlorohydrin-based polyLirethane/poly(methyl methacrylate) interpenetrating polymer networks (PU(PECH)/PMMA IPNs) were synthesized by adjust-ing composition,molecular weight of PECH,R vahe (isocyanate/hydroxyl ratio),iso-cyanate and crosslinking reagent contents of PU and PMMA,respectively. The tensile strength,elongation at break and modulus of IPNs were measured,and they varied with the synthetic condition greatly. DSC,TEM,dynamic mechanical spectroscopy were employed to explain the changes of mechanical properties. Changes in structure,such as crosslink, inter-penetration and entanglement result in the changes of mechanical properties.
Five series of polyepichlorohydrin-based polyLirethane/poly(methyl methacrylate) interpenetrating polymer networks (PU(PECH)/PMMA IPNs) were synthesized by adjust-ing composition,molecular weight of PECH,R vahe (isocyanate/hydroxyl ratio),iso-cyanate and crosslinking reagent contents of PU and PMMA,respectively. The tensile strength,elongation at break and modulus of IPNs were measured,and they varied with the synthetic condition greatly. DSC,TEM,dynamic mechanical spectroscopy were employed to explain the changes of mechanical properties. Changes in structure,such as crosslink, inter-penetration and entanglement result in the changes of mechanical properties.
1995, 12(4): 70-73
Abstract:
In this paper,the morphologies of polymer particles in polyether polyol (POP) have been observed,which was prepared from styrene and acrylonitrile by using dispersion polymerization in polyether polyol under various conditions. It has been found that techno-logical conditions can change the morphologies of the particles and then affect the properties of POP. Aggregation of the particles is a main factor that influences the stability and viscosi-ty of the dispersion. Separate spheres with smooth surface can be obtained under suitable conditions and the corresponding POP is of lower viscosity.
In this paper,the morphologies of polymer particles in polyether polyol (POP) have been observed,which was prepared from styrene and acrylonitrile by using dispersion polymerization in polyether polyol under various conditions. It has been found that techno-logical conditions can change the morphologies of the particles and then affect the properties of POP. Aggregation of the particles is a main factor that influences the stability and viscosi-ty of the dispersion. Separate spheres with smooth surface can be obtained under suitable conditions and the corresponding POP is of lower viscosity.
1995, 12(4): 74-79
Abstract:
Thirteen trialkyltin oximes were synthesized and the NMR(1H,13C,119Sn),MS and elemental analysis were determined. The results showed that this kind of compounds might be four-coordinated organotin compounds. The preliminary bioassay tests show that these compounds have good acaricidal and fungicidal activities.
Thirteen trialkyltin oximes were synthesized and the NMR(1H,13C,119Sn),MS and elemental analysis were determined. The results showed that this kind of compounds might be four-coordinated organotin compounds. The preliminary bioassay tests show that these compounds have good acaricidal and fungicidal activities.
1995, 12(4): 80-83
Abstract:
Thirty stibstituted amides have been synthesized with their structures being con-firmed by 1H NMR, IR and elemental analysis. Most of the compounds showed an inhibition effect on rice growth.
Thirty stibstituted amides have been synthesized with their structures being con-firmed by 1H NMR, IR and elemental analysis. Most of the compounds showed an inhibition effect on rice growth.
1995, 12(4): 84-86
Abstract:
The silane coupling agents were found to be effective to improve the mechanical properties of wollastonite-filled nylon 66(W-PA66). Results showed that with the increase of the filler content,the tensile and flextiral properties of the composites were improved and the best machanical properties were observed when the wollastonite content was 40%.
The silane coupling agents were found to be effective to improve the mechanical properties of wollastonite-filled nylon 66(W-PA66). Results showed that with the increase of the filler content,the tensile and flextiral properties of the composites were improved and the best machanical properties were observed when the wollastonite content was 40%.
1995, 12(4): 87-89
Abstract:
Formation of nitrogen oxides in the oxidation of pyridine over different γ-Al2O3 supported oxide catalysts has been studied in the temperature range of 200~700℃. The oxi-dation activity and the ability to control NOx formation were found to be decreased in the or-der: Ag-O > Cu-O > Mn-O > Cr-O > Fe-O > Co-O > Ni-O > V-O > Ce-O. NOx formation con-trol ability appeared in relation to the basicity of the catalyst surface.
Formation of nitrogen oxides in the oxidation of pyridine over different γ-Al2O3 supported oxide catalysts has been studied in the temperature range of 200~700℃. The oxi-dation activity and the ability to control NOx formation were found to be decreased in the or-der: Ag-O > Cu-O > Mn-O > Cr-O > Fe-O > Co-O > Ni-O > V-O > Ce-O. NOx formation con-trol ability appeared in relation to the basicity of the catalyst surface.
1995, 12(4): 90-92
Abstract:
Three chiral liquid crystals with Schiff base group have been prepared. The struc-tures of the liquid crystals were confirmed by elemental analysis and 1H NMR. The phase transition was investigated by the methods of polarized microscopy,DSC and WAXD. The results show that two of the liquid crystals are ferroelectric.
Three chiral liquid crystals with Schiff base group have been prepared. The struc-tures of the liquid crystals were confirmed by elemental analysis and 1H NMR. The phase transition was investigated by the methods of polarized microscopy,DSC and WAXD. The results show that two of the liquid crystals are ferroelectric.
1995, 12(4): 93-95
Abstract:
When Mckillop's method was used,oxidation of cyano-containing organic sulfides to the corresponding stilfones with sodium perborate tetrahydrate (NaBO3·4H2O) caused the hydrolysis of cyano group. However,with our modified procedure in which the reagent sodium perborate was added in small portions at 55~65℃,sulfones and sulfoxides could be selectively obtained and the cyano group was not touched.
When Mckillop's method was used,oxidation of cyano-containing organic sulfides to the corresponding stilfones with sodium perborate tetrahydrate (NaBO3·4H2O) caused the hydrolysis of cyano group. However,with our modified procedure in which the reagent sodium perborate was added in small portions at 55~65℃,sulfones and sulfoxides could be selectively obtained and the cyano group was not touched.
1995, 12(4): 96-98
Abstract:
The comblike polymer based on methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene chains (BM350) dissolved NaClO4,forming a homogeneous amor-phous polymer electrolyte. The Tg of the polymer were found to be increased with salt addi-tion. The BM350/NaClO4 complex at a [Na]/[EO] ratio of 0.25 exhibited ionic conductivityof 1.03 × 10-4S/cm at 25℃. The conductivity of the polymer electrolytes obeys the VTF e-quation and has been discussed in terms of the changes in confugurations.
The comblike polymer based on methyl vinyl ether/maleic anhydride copolymer with oligo-oxyethylene chains (BM350) dissolved NaClO4,forming a homogeneous amor-phous polymer electrolyte. The Tg of the polymer were found to be increased with salt addi-tion. The BM350/NaClO4 complex at a [Na]/[EO] ratio of 0.25 exhibited ionic conductivityof 1.03 × 10-4S/cm at 25℃. The conductivity of the polymer electrolytes obeys the VTF e-quation and has been discussed in terms of the changes in confugurations.
1995, 12(4): 99-101
Abstract:
Addition of aroyl hydrazines(Ⅰ) with thiophosphoryl isothiocyanates(Ⅱ) gives 14 title aminothiotireas(Ⅲ). Their structures were characterized by 1H NMR,IR and ele-mentary analysis. Some compounds showed fungicidal and plant-growth regulator activities.
Addition of aroyl hydrazines(Ⅰ) with thiophosphoryl isothiocyanates(Ⅱ) gives 14 title aminothiotireas(Ⅲ). Their structures were characterized by 1H NMR,IR and ele-mentary analysis. Some compounds showed fungicidal and plant-growth regulator activities.
1995, 12(4): 102-104
Abstract:
The structtiral unit of network and chemical state of constituent elements for the oxysulfide glasses in the system Li2S-B2O3-LiBr were studied by using X-ray photoelectron spectroscopy. The results indicate that sulfur in the form of S2- participates in network for-mation of glasses as coordinated ion and the glasses with R < 0.4 have no nonbridging sulfur ions. So,the binding energies(BE) of S2p do not show appreciable change with the variation of modifier Li2S content. However, when R≥0.4,BE of S2p significantly decreases with the addition of Li2S that is caused by the existence of the nonbridging sulfur ions. The binding energy of Li1s in the glasses is found to increase gradually with the increase of LiBr dopant content. This implies that LiBr is only dissolved in glass matrix entering the network inter-stitially as dissociated ions,and the Li- ions surrounded by Br- ions mainly take part in con-duction.
The structtiral unit of network and chemical state of constituent elements for the oxysulfide glasses in the system Li2S-B2O3-LiBr were studied by using X-ray photoelectron spectroscopy. The results indicate that sulfur in the form of S2- participates in network for-mation of glasses as coordinated ion and the glasses with R < 0.4 have no nonbridging sulfur ions. So,the binding energies(BE) of S2p do not show appreciable change with the variation of modifier Li2S content. However, when R≥0.4,BE of S2p significantly decreases with the addition of Li2S that is caused by the existence of the nonbridging sulfur ions. The binding energy of Li1s in the glasses is found to increase gradually with the increase of LiBr dopant content. This implies that LiBr is only dissolved in glass matrix entering the network inter-stitially as dissociated ions,and the Li- ions surrounded by Br- ions mainly take part in con-duction.
1995, 12(4): 105-107
Abstract:
This paper reports the N-alkylation of α-pyrrolidone or ε-caprolactam with alkyl halide under microwave irradiation by using solid reagents as a supporter. Ten lactam deriva-tives were obtained. The effects of basic supporter,reaction time and microwave power on the alkvlation were discussed.
This paper reports the N-alkylation of α-pyrrolidone or ε-caprolactam with alkyl halide under microwave irradiation by using solid reagents as a supporter. Ten lactam deriva-tives were obtained. The effects of basic supporter,reaction time and microwave power on the alkvlation were discussed.
1995, 12(4): 108-110
Abstract:
The ashing temperature could be increased and some interferences from hy-drochloric acid,molybdenum and boron could be eliminated in title method by using Pd and Ni as a matrix modifier. The method can be used directly for lead and antimony analys is inhigh temperature nickel-alloy without preseparation of the matrix. The characteristic mass is 28pg and 26pg, the detection limit is 0.13μg/g and 0.23μg/g,the recovery is 94%~103% and 95%~110%,the relative standard deviation is 6.4%~7.6% and 4.7%~7.5% for lead and antimony,respectively.
The ashing temperature could be increased and some interferences from hy-drochloric acid,molybdenum and boron could be eliminated in title method by using Pd and Ni as a matrix modifier. The method can be used directly for lead and antimony analys is inhigh temperature nickel-alloy without preseparation of the matrix. The characteristic mass is 28pg and 26pg, the detection limit is 0.13μg/g and 0.23μg/g,the recovery is 94%~103% and 95%~110%,the relative standard deviation is 6.4%~7.6% and 4.7%~7.5% for lead and antimony,respectively.
1995, 12(4): 111-113
Abstract:
The photochemical reaction of dichromated gelatin was studied by laser photoa-coustic spectroscopy. Results show that the solid-state reaction of the dichromate with gelatin obeys Watanabe-Westheimer reaction scheme. The photosensitivity of dichromated gelatin is dependent on pH and concentration of dichromate solution.
The photochemical reaction of dichromated gelatin was studied by laser photoa-coustic spectroscopy. Results show that the solid-state reaction of the dichromate with gelatin obeys Watanabe-Westheimer reaction scheme. The photosensitivity of dichromated gelatin is dependent on pH and concentration of dichromate solution.
1995, 12(4): 114-115
Abstract:
The reactivation of the waste commercial Ni/Al2O3 catalyst used in reforming of methane or natural gas by carbon dioxide has been studied on a fixed-bed flow apparatus by using XRD and TPR techniques. It is found that if the waste catalyst is first reduced at 1193K,then treated with 20% aqueous hydrogen peroxide solution(disperser),the activity could be renewed to that of the fresh one.
The reactivation of the waste commercial Ni/Al2O3 catalyst used in reforming of methane or natural gas by carbon dioxide has been studied on a fixed-bed flow apparatus by using XRD and TPR techniques. It is found that if the waste catalyst is first reduced at 1193K,then treated with 20% aqueous hydrogen peroxide solution(disperser),the activity could be renewed to that of the fresh one.
1995, 12(4): 116-117
Abstract:
Seven derivatives of 2-heterobenzopyrone have been synthesised and characterized by elemental analysis and spectral data. Some derivatives showed good bacteriostatic activi-ty.
Seven derivatives of 2-heterobenzopyrone have been synthesised and characterized by elemental analysis and spectral data. Some derivatives showed good bacteriostatic activi-ty.
