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2006 Volume 23 Issue 12
2006, 23(12): 1309-1312
Abstract:
Al and Co co-doped α-Ni(OH)2 sample was prepared by a solid state reaction at a relatively low temperature.Its structure and electrochemical behaviors were investigated.The results of X-ray diffraction(XRD) show that Al and Co co-doped α-Ni(OH)2 maintains the structure of α-Ni(OH)2 in 6 mol/L KOH solution for 6 months and keeps the structure of α-Ni(OH)2 after 30 cycles of charge/discharge.The results of the electrochemical experiments show that Al and Co co-doped α-Ni(OH)2 exhibits a larger discharge capacity and a higher discharge potential and a high current density property than Al doped α-Ni(OH)2 and spherical β-Ni(OH)2.
Al and Co co-doped α-Ni(OH)2 sample was prepared by a solid state reaction at a relatively low temperature.Its structure and electrochemical behaviors were investigated.The results of X-ray diffraction(XRD) show that Al and Co co-doped α-Ni(OH)2 maintains the structure of α-Ni(OH)2 in 6 mol/L KOH solution for 6 months and keeps the structure of α-Ni(OH)2 after 30 cycles of charge/discharge.The results of the electrochemical experiments show that Al and Co co-doped α-Ni(OH)2 exhibits a larger discharge capacity and a higher discharge potential and a high current density property than Al doped α-Ni(OH)2 and spherical β-Ni(OH)2.
2006, 23(12): 1313-1316
Abstract:
This paper reports the application of fluorescence anisotropy technique to the assay of proteases via a protein substrate labeled with tetramethyl isothiocyanate rhodmine(TMRITC).The linear ranges for the assay of pepsin,bromelain and trypsin are 5.0×10-8~3.0×10-6,5.0×10-8~3.0×10-6,and 3.3×10-6~3.0×10-6 g/mL,respectively.The detection limits of the three proteases mentioned above are 26.1×10-9,14.7×10-9,5.4×10-8 g/mL,respectively.The method is suitable for the real-time quantitative and homogeneous determination of a variety of proteases,because the fluorescence behavior of TMRITC is hardly affected in a wide range of pH.The substrate can be prepared easily and is stable under conventional conditions.On the other hand,the emission-wavelength of TMRITC is longer than that of fluorescein isothiocyanate(FITC),a conventional fluorescence probe for tagging proteins,thus it improves the detection of fluorescence anisotropy.In addition,this method is suitable for the determination of protease inhibitors,such as aprotinin,an inhibitor of trypsin.
This paper reports the application of fluorescence anisotropy technique to the assay of proteases via a protein substrate labeled with tetramethyl isothiocyanate rhodmine(TMRITC).The linear ranges for the assay of pepsin,bromelain and trypsin are 5.0×10-8~3.0×10-6,5.0×10-8~3.0×10-6,and 3.3×10-6~3.0×10-6 g/mL,respectively.The detection limits of the three proteases mentioned above are 26.1×10-9,14.7×10-9,5.4×10-8 g/mL,respectively.The method is suitable for the real-time quantitative and homogeneous determination of a variety of proteases,because the fluorescence behavior of TMRITC is hardly affected in a wide range of pH.The substrate can be prepared easily and is stable under conventional conditions.On the other hand,the emission-wavelength of TMRITC is longer than that of fluorescein isothiocyanate(FITC),a conventional fluorescence probe for tagging proteins,thus it improves the detection of fluorescence anisotropy.In addition,this method is suitable for the determination of protease inhibitors,such as aprotinin,an inhibitor of trypsin.
2006, 23(12): 1317-1322
Abstract:
A method for the determination of miconazole nitrate in two different medicines by capillary electrophoresis with high frequency conductivity detection(contactless conductivity detection) was established.The electrophoretic parameters, such as the variety and concentration of buffer solution,separation voltage etc,were researched.Miconazole nitrate was separated and detected in a buffer(3.0 mmol/L lactic acid+10% ethanol(pH=4.0)) at 20.0 kV constant voltage.The linear dependence of the concentrations of miconazole nitrate ranged from 20.0 to 900 mg/L(r=0.999 4),and the limit of detection(LOD) reached 1.0 mg/L (S/N=)3.The RSDs for both intra-day and inter-day were less than 3% and the recoveries were 94.9%~101% and 95.3%~99.1% for Miconazole-nitrate-cream and Miconazole-nitrate-vaginal-suppositories suppository respectively at various spiked levels.This method may be useful for the determination of miconazole nitrate in compound preparations.It could be used for quality control of products due to its simplicity,rapidity and sensitivity.
A method for the determination of miconazole nitrate in two different medicines by capillary electrophoresis with high frequency conductivity detection(contactless conductivity detection) was established.The electrophoretic parameters, such as the variety and concentration of buffer solution,separation voltage etc,were researched.Miconazole nitrate was separated and detected in a buffer(3.0 mmol/L lactic acid+10% ethanol(pH=4.0)) at 20.0 kV constant voltage.The linear dependence of the concentrations of miconazole nitrate ranged from 20.0 to 900 mg/L(r=0.999 4),and the limit of detection(LOD) reached 1.0 mg/L (S/N=)3.The RSDs for both intra-day and inter-day were less than 3% and the recoveries were 94.9%~101% and 95.3%~99.1% for Miconazole-nitrate-cream and Miconazole-nitrate-vaginal-suppositories suppository respectively at various spiked levels.This method may be useful for the determination of miconazole nitrate in compound preparations.It could be used for quality control of products due to its simplicity,rapidity and sensitivity.
2006, 23(12): 1323-1326
Abstract:
A series of supported NiB and NiCoB amorphous alloy catalysts was prepared by means of the metal inducing electroless plating and their catalytic activities were measured by hydrogenation of dimethyl aminoureazinic acid.The results show that the supported amorphous alloy catalysts show a high activity in the hydrogenation reaction.The NiCoB/SiO2 showed the same catalytic activity as Raney Ni.The best reaction conditions over NiCoB/SiO2 are as follows: Ni and Co loadings of NiCoB/SiO2 are 4% and 3% respectively;catalyst is stored after drying;the reaction temperature should be controlled around 60℃.
A series of supported NiB and NiCoB amorphous alloy catalysts was prepared by means of the metal inducing electroless plating and their catalytic activities were measured by hydrogenation of dimethyl aminoureazinic acid.The results show that the supported amorphous alloy catalysts show a high activity in the hydrogenation reaction.The NiCoB/SiO2 showed the same catalytic activity as Raney Ni.The best reaction conditions over NiCoB/SiO2 are as follows: Ni and Co loadings of NiCoB/SiO2 are 4% and 3% respectively;catalyst is stored after drying;the reaction temperature should be controlled around 60℃.
2006, 23(12): 1327-1331
Abstract:
Nano-SiO2/acrylic resin composite latex was synthesized in the presence of nano-SiO2,which was modified by silane coupling agent.The FT-IR analysis showed that the spectrum of the composite latex had all the characteristic bands of nano-silica and pure polyacrylate latex.The thermal analysis showed that the addition of nano-SiO2 raised the rigidity of acrylic molecules,generated cross linkage and induced the free radical from the thermal degradation,which improved the thermal stability of the composite latex.The thermal degradation activation energy of 3% ω(SiO2) is 298.40 kJ/mol,which quantitatively explains the improvement of the thermal stability after the addition of nano-SiO2.
Nano-SiO2/acrylic resin composite latex was synthesized in the presence of nano-SiO2,which was modified by silane coupling agent.The FT-IR analysis showed that the spectrum of the composite latex had all the characteristic bands of nano-silica and pure polyacrylate latex.The thermal analysis showed that the addition of nano-SiO2 raised the rigidity of acrylic molecules,generated cross linkage and induced the free radical from the thermal degradation,which improved the thermal stability of the composite latex.The thermal degradation activation energy of 3% ω(SiO2) is 298.40 kJ/mol,which quantitatively explains the improvement of the thermal stability after the addition of nano-SiO2.
2006, 23(12): 1332-1335
Abstract:
Preparation of biodiesel from rapeseed via extraction and in-situ transesterification in supercritical methanol was discussed.The main components of the biodiesel were methyl linoleate,methyl oleate,methyl palmitate,methyl stearate and methyl linolenate.Reaction temperature, reaction pressure and mass ratio of rapeseed to methanol had an important effect on the conversion of the rapeseed oil.The 94.3% oil conversion can be achieved at 280℃ and 14 MPa within 10 min at the mass ratio of rapeseed to methanol of 1:4.
Preparation of biodiesel from rapeseed via extraction and in-situ transesterification in supercritical methanol was discussed.The main components of the biodiesel were methyl linoleate,methyl oleate,methyl palmitate,methyl stearate and methyl linolenate.Reaction temperature, reaction pressure and mass ratio of rapeseed to methanol had an important effect on the conversion of the rapeseed oil.The 94.3% oil conversion can be achieved at 280℃ and 14 MPa within 10 min at the mass ratio of rapeseed to methanol of 1:4.
2006, 23(12): 1336-1341
Abstract:
With chitosan as the functional matrix(FMx) and L-Proline(L-Pro) as the template molecule, molecularly imprinting polymer with both the spatial configuration and bonding sites matching to L-Proline was synthesised by means of the molecularly imprinting technology in water.The polymer product was characterized by IR,SEM and TG.Furthermore,the mechanism was explored preliminarily.The effects of pH,the amount of cross-linking agent and reaction time were studied.The optimum conditions were: pH=10.7,composite 1.0 g,cross-linking agent 8 mL,18 h at ambient temperature.The experimental results show that L-Pro-MIP has a superior selective adsorption capacity and efficient chiral separation of L-Proline in water phase,the resolution factor is 4.67.
With chitosan as the functional matrix(FMx) and L-Proline(L-Pro) as the template molecule, molecularly imprinting polymer with both the spatial configuration and bonding sites matching to L-Proline was synthesised by means of the molecularly imprinting technology in water.The polymer product was characterized by IR,SEM and TG.Furthermore,the mechanism was explored preliminarily.The effects of pH,the amount of cross-linking agent and reaction time were studied.The optimum conditions were: pH=10.7,composite 1.0 g,cross-linking agent 8 mL,18 h at ambient temperature.The experimental results show that L-Pro-MIP has a superior selective adsorption capacity and efficient chiral separation of L-Proline in water phase,the resolution factor is 4.67.
2006, 23(12): 1342-1345
Abstract:
Cu(IO3)2 was prepared by solution reaction and solid phase reaction, respectively.The different morphologies and electrochemical properties of the as-prepared materials were studied by means of SEM,X-ray diffraction(XRD),AC impedance,line sweep voltammetry and galvanostatic discharge experiments.The results show that the Cu(IO3)2 prepared by the solid-state reaction method shows better electrochemical properties,and the actual discharge capacity reaches to 891.5 mA·h/g close to the theoretical capacity,900 mA·h/g of Cu(IO3)2.
Cu(IO3)2 was prepared by solution reaction and solid phase reaction, respectively.The different morphologies and electrochemical properties of the as-prepared materials were studied by means of SEM,X-ray diffraction(XRD),AC impedance,line sweep voltammetry and galvanostatic discharge experiments.The results show that the Cu(IO3)2 prepared by the solid-state reaction method shows better electrochemical properties,and the actual discharge capacity reaches to 891.5 mA·h/g close to the theoretical capacity,900 mA·h/g of Cu(IO3)2.
2006, 23(12): 1346-1349
Abstract:
Nanocrystalline NiO was synthesized by pyrolysis of Ni(OH)2 precursor at 300℃,and alkaline solid polymer electrolyte,PVA-KOH(5 mol/L)-H2O,was prepared via solution-casting technique,and alkaline NiO-based allsolid-state supercapacitor was fabricated with the nanocrystalline NiO as electroactive material and the alkaline solid polymer electrolyte as electrolyte and spacer.XRD and HRTEM demonstrated that the size of the nanocrystalline NiO with good dispersion was ca.5 nm.Cyclic voltammgoram,galvanostatic charge-discharge,A.C.impedance,leakage current,self-discharge and cycle life tests indicated that all the alkaline all-solid-state supercapacitor exhibited good electrochemical capacitance performance.The specific capacitance and energy density of the supercapacitor were 103.2 F/g and 11.6 kW/kg,respectively,at a current density of 0.2 A/g.Also,the all-solid-state supercapacitor exhibited a good electrochemical stability with a capacitance degradation of 10% over 1 500 cycles.
Nanocrystalline NiO was synthesized by pyrolysis of Ni(OH)2 precursor at 300℃,and alkaline solid polymer electrolyte,PVA-KOH(5 mol/L)-H2O,was prepared via solution-casting technique,and alkaline NiO-based allsolid-state supercapacitor was fabricated with the nanocrystalline NiO as electroactive material and the alkaline solid polymer electrolyte as electrolyte and spacer.XRD and HRTEM demonstrated that the size of the nanocrystalline NiO with good dispersion was ca.5 nm.Cyclic voltammgoram,galvanostatic charge-discharge,A.C.impedance,leakage current,self-discharge and cycle life tests indicated that all the alkaline all-solid-state supercapacitor exhibited good electrochemical capacitance performance.The specific capacitance and energy density of the supercapacitor were 103.2 F/g and 11.6 kW/kg,respectively,at a current density of 0.2 A/g.Also,the all-solid-state supercapacitor exhibited a good electrochemical stability with a capacitance degradation of 10% over 1 500 cycles.
2006, 23(12): 1350-1354
Abstract:
Solid superacid catalyst SO42-/TiO2-Ce4+ was prepared by two-phase precipitation,and preparation conditions for the catalyst suitable for the synthesis of poly(lactic acid) through condesation of lactic acid monomer were studied.The optimum preparation conditions for the catalyst were 1.0 mol/L of H2SO4,0.08 mol/L of Ce4+,immersion time 10 h,and 3 h calcination at 500℃.The above catalyst was used in the synthesis of poly(lactic acid) through condesation.The effect of reaction temperature,reaction time,reaction pressure and catalyst amount on the condesation of lactic acid was studied.The optimum reaction conditions were obtained,which were the amount of catalyst 0.174% vs lactic acid,prepolymerization for 5 h at 120℃ and 2 000 Pa,then polymerization for 15 h at 180℃ and 1 000 Pa,and last polymerization for 20 h at 120℃ and 500 Pa.The viscosity average molecular weight of the poly(lactic acid) was 1.39×104.
Solid superacid catalyst SO42-/TiO2-Ce4+ was prepared by two-phase precipitation,and preparation conditions for the catalyst suitable for the synthesis of poly(lactic acid) through condesation of lactic acid monomer were studied.The optimum preparation conditions for the catalyst were 1.0 mol/L of H2SO4,0.08 mol/L of Ce4+,immersion time 10 h,and 3 h calcination at 500℃.The above catalyst was used in the synthesis of poly(lactic acid) through condesation.The effect of reaction temperature,reaction time,reaction pressure and catalyst amount on the condesation of lactic acid was studied.The optimum reaction conditions were obtained,which were the amount of catalyst 0.174% vs lactic acid,prepolymerization for 5 h at 120℃ and 2 000 Pa,then polymerization for 15 h at 180℃ and 1 000 Pa,and last polymerization for 20 h at 120℃ and 500 Pa.The viscosity average molecular weight of the poly(lactic acid) was 1.39×104.
2006, 23(12): 1355-1358
Abstract:
4-(2-Hydroxy-phenyl)-but-3-en-2-one was prepared via condensation of salicylaldehyde with acetone,and then cyclization of the α,β-unsaturated ketones with thiosemicarbzide.Seven new 5-(2-hydroxyphenyl)-3-methyl-4,5-dihydropyrazole-1-carbothioamide derivatives were synthesized and characterized by means of elemental analysis,IR and 1H NMR.The compounds 3c,3d,3g showed certain bactericidal activity against E. coli;compound 3g show certain bactericidal activity against P.vulgaris.
4-(2-Hydroxy-phenyl)-but-3-en-2-one was prepared via condensation of salicylaldehyde with acetone,and then cyclization of the α,β-unsaturated ketones with thiosemicarbzide.Seven new 5-(2-hydroxyphenyl)-3-methyl-4,5-dihydropyrazole-1-carbothioamide derivatives were synthesized and characterized by means of elemental analysis,IR and 1H NMR.The compounds 3c,3d,3g showed certain bactericidal activity against E. coli;compound 3g show certain bactericidal activity against P.vulgaris.
2006, 23(12): 1359-1363
Abstract:
The catalytic hydrogen wave of nimesulide was measured at ca. -1.20 V(vs.SCE) in 0.10 mol/L KH2PO4-Na2HPO4(pH=6.24±0.1) aqueous solution.When 1.0×10-2 mol/L K2S2O8 is present,the current increases by 20 times,and the peak potential is unchanged,producing a more sensitive parallel catalytic hydrogen wave.The peak current of the parallel catalytic hydrogen wave is proportional to the nimesulide concentration in the range 2.0×10-7~80×10-6 mol/L(r=0.988 6,n=9).The detection limit is 2.0×10-7 mol/L.The proposed method can be applied to the determination of nimesulide in pharmaceuticals without preliminary separation.
The catalytic hydrogen wave of nimesulide was measured at ca. -1.20 V(vs.SCE) in 0.10 mol/L KH2PO4-Na2HPO4(pH=6.24±0.1) aqueous solution.When 1.0×10-2 mol/L K2S2O8 is present,the current increases by 20 times,and the peak potential is unchanged,producing a more sensitive parallel catalytic hydrogen wave.The peak current of the parallel catalytic hydrogen wave is proportional to the nimesulide concentration in the range 2.0×10-7~80×10-6 mol/L(r=0.988 6,n=9).The detection limit is 2.0×10-7 mol/L.The proposed method can be applied to the determination of nimesulide in pharmaceuticals without preliminary separation.
2006, 23(12): 1364-1367
Abstract:
With α-napthaleneacetic acid as precursor,three thiourea derivatives and three carboxamides derivatives were synthesized by solid-liquid phase transfer catalytic reaction.Compounds 3a,3b,3d,3e,3f are new compounds.The structures were confirmed by means of IR,1H NMR,MS and elemental analysis.The results of biological test show that all of these compounds have good antifungicidal activities.The anti-fungal activities to Fusarium moniliforme could reach 70% when their centrations is around 50 mg/L.
With α-napthaleneacetic acid as precursor,three thiourea derivatives and three carboxamides derivatives were synthesized by solid-liquid phase transfer catalytic reaction.Compounds 3a,3b,3d,3e,3f are new compounds.The structures were confirmed by means of IR,1H NMR,MS and elemental analysis.The results of biological test show that all of these compounds have good antifungicidal activities.The anti-fungal activities to Fusarium moniliforme could reach 70% when their centrations is around 50 mg/L.
2006, 23(12): 1368-1372
Abstract:
The sodium thioglycollate modified ZnS with an average particle size of 2~4 nm was synthesized via the solid phase reaction method at room temperature using zinc acetate,Na2S and thioglycollic acid as raw materials.Its composition and structure were characterized by several spectroscopic techniques.It was found that the aggregation of ZnS is prevented because of the presence of sodium thioglycollate,while ensure its uniform dispersion in aqueous solution.The sodium thioglycollate modified ZnS shows high photocatalytic activity for the degredation of methyl orage,which is affected by the pH value of the solution.When the pH of the solution is 3.5,the photocatlytic activity of sodium thioglycollate modified ZnS for the photodegradation of methyl orange can reach as high as 99.4%.
The sodium thioglycollate modified ZnS with an average particle size of 2~4 nm was synthesized via the solid phase reaction method at room temperature using zinc acetate,Na2S and thioglycollic acid as raw materials.Its composition and structure were characterized by several spectroscopic techniques.It was found that the aggregation of ZnS is prevented because of the presence of sodium thioglycollate,while ensure its uniform dispersion in aqueous solution.The sodium thioglycollate modified ZnS shows high photocatalytic activity for the degredation of methyl orage,which is affected by the pH value of the solution.When the pH of the solution is 3.5,the photocatlytic activity of sodium thioglycollate modified ZnS for the photodegradation of methyl orange can reach as high as 99.4%.
2006, 23(12): 1373-1376
Abstract:
Kevlar fiber was modified by means of the anionic graft of nylon 6 oligomer.Nylon 6/modified Kevlar fiber(PA6/KF1) composites were prepared by extrusion and injection process.Both ESEM and XPS measurements proved that the nylon 6 oligomer was grafted onto the surface of Kevlar fiber.The mechanical properties,fracture morphologies and fracture mechanism of PA6/KF0 and PA6/KF1 composites were compared and studied.After being treated,the composites' tensile strength,flexural strength and flexural modulus were increased by 20.69%,12.26% and 14.23% respectively,however,the impact strength declined by 8.2%.The adhesive nylon 6 on the PA6/KF1 composites was more than that on the PA6/KF0 composites when the composites were destroyed,and the failure morphology of PA6/KF1 composites was non-interfacial destruction.
Kevlar fiber was modified by means of the anionic graft of nylon 6 oligomer.Nylon 6/modified Kevlar fiber(PA6/KF1) composites were prepared by extrusion and injection process.Both ESEM and XPS measurements proved that the nylon 6 oligomer was grafted onto the surface of Kevlar fiber.The mechanical properties,fracture morphologies and fracture mechanism of PA6/KF0 and PA6/KF1 composites were compared and studied.After being treated,the composites' tensile strength,flexural strength and flexural modulus were increased by 20.69%,12.26% and 14.23% respectively,however,the impact strength declined by 8.2%.The adhesive nylon 6 on the PA6/KF1 composites was more than that on the PA6/KF0 composites when the composites were destroyed,and the failure morphology of PA6/KF1 composites was non-interfacial destruction.
2006, 23(12): 1377-1380
Abstract:
Under microwave irradiation,N-phenacylpyridinium chloride 1 reacted with chalcone 2 in the presence of ammonium acetate to afford 2,4,6-triarylpyrididnes 5a~5h in high yields.2,4,6-Triarylpyridines 5a~5h can also be prepared from the one-pot reaction of N-phenacylpyridinium chloride with each of aromatic aldehydes 3 and each of substituted acetophenones 4.The products were identified by 1H NMR and IR spectroscopy.
Under microwave irradiation,N-phenacylpyridinium chloride 1 reacted with chalcone 2 in the presence of ammonium acetate to afford 2,4,6-triarylpyrididnes 5a~5h in high yields.2,4,6-Triarylpyridines 5a~5h can also be prepared from the one-pot reaction of N-phenacylpyridinium chloride with each of aromatic aldehydes 3 and each of substituted acetophenones 4.The products were identified by 1H NMR and IR spectroscopy.
2006, 23(12): 1381-1384
Abstract:
Ultrasonic waves have been utilized in organic synthesis for their low reaction temperature and simple operation as compared with the conventional heating method.The use of ultrasonic irradiation in the presence of PTC for organic synthesis is well documented.Nine new N'-(4,6-disubstituted pyrimidin-2-yl)-N-cinnamoyl thioureas(4a~4i) were synthesized under ultrasonic irradiation in the presence of PTC.The structures of all the novel target compounds were confirmed by means of IR,1H NMR and elemental analysis.The ultrasonic-irradiation and phase-transfer catalyst reduced the reaction temperature from 90℃ to 60℃,and the reaction time was shortened by 3 h,while,the reaction yield improved from 49% to 70%.The preliminary biological activity of the target compounds have been tested.
Ultrasonic waves have been utilized in organic synthesis for their low reaction temperature and simple operation as compared with the conventional heating method.The use of ultrasonic irradiation in the presence of PTC for organic synthesis is well documented.Nine new N'-(4,6-disubstituted pyrimidin-2-yl)-N-cinnamoyl thioureas(4a~4i) were synthesized under ultrasonic irradiation in the presence of PTC.The structures of all the novel target compounds were confirmed by means of IR,1H NMR and elemental analysis.The ultrasonic-irradiation and phase-transfer catalyst reduced the reaction temperature from 90℃ to 60℃,and the reaction time was shortened by 3 h,while,the reaction yield improved from 49% to 70%.The preliminary biological activity of the target compounds have been tested.
2006, 23(12): 1385-1390
Abstract:
After comparing the effects of three kinds of nano-carbon materials,namely,carbon nanotubes(CNTs),carbon black and chemical vapor deposit carbon fibers on the LiCoO2 cathode,the results indicate that the kind of nano-carbon conductive additives plays an important role in the electrochemical behavior of the cathode.Spherical carbon black prevent the formation of conductive network and therefore leads to a serious polarization.In contrast,wire-like conductive additives,especially CNTs,exhibit better electrontransfer ability,forms better conductive network in the cathode and hence alleviate the degree of cathode polarization owing to their high crystallinity,well ordered one-dimensional and cylindrical structure.Much amount of conductive additives and binder could be saved by utilizing CNTs, and the cathode with only 3% of conductive additive CNTs shows excellent rate capacity.At the discharge rate of 2.0C,the LiCoO2 cathode with CNTs still holds 95% of the discharge capacity shown at the discharge rate of 0.5C.
After comparing the effects of three kinds of nano-carbon materials,namely,carbon nanotubes(CNTs),carbon black and chemical vapor deposit carbon fibers on the LiCoO2 cathode,the results indicate that the kind of nano-carbon conductive additives plays an important role in the electrochemical behavior of the cathode.Spherical carbon black prevent the formation of conductive network and therefore leads to a serious polarization.In contrast,wire-like conductive additives,especially CNTs,exhibit better electrontransfer ability,forms better conductive network in the cathode and hence alleviate the degree of cathode polarization owing to their high crystallinity,well ordered one-dimensional and cylindrical structure.Much amount of conductive additives and binder could be saved by utilizing CNTs, and the cathode with only 3% of conductive additive CNTs shows excellent rate capacity.At the discharge rate of 2.0C,the LiCoO2 cathode with CNTs still holds 95% of the discharge capacity shown at the discharge rate of 0.5C.
2006, 23(12): 1391-1395
Abstract:
Modified poly-acrylate esters(PADE) and 3,6-endooxo-bridge-1,2,3,6-tetrahydrobenzene-1,2-difomicanhydride(EBTD) as a new dispersant of paraffin crystals were synthesized and evaluated in laboratory as cold flow improver for 0# diesels.It was shown that PADE had the ability of dispersion of wax crystals.It is superior to some other pour point depressants in improving low temperature performance of yanshan 0#,dalian 0# and liaohe 0# diesels,while the cold filter plugging point is reduced from 7℃ to 10℃.Its sensitivity to Daqing 0# diesel is also effective.There is a synergistic effect between the PADE and EBTD.The synergism could improve low temperature performance of Daqing 0# diesel and could reduce the cold filter plugging point of Daqing 0# diesel by 7~8℃.
Modified poly-acrylate esters(PADE) and 3,6-endooxo-bridge-1,2,3,6-tetrahydrobenzene-1,2-difomicanhydride(EBTD) as a new dispersant of paraffin crystals were synthesized and evaluated in laboratory as cold flow improver for 0# diesels.It was shown that PADE had the ability of dispersion of wax crystals.It is superior to some other pour point depressants in improving low temperature performance of yanshan 0#,dalian 0# and liaohe 0# diesels,while the cold filter plugging point is reduced from 7℃ to 10℃.Its sensitivity to Daqing 0# diesel is also effective.There is a synergistic effect between the PADE and EBTD.The synergism could improve low temperature performance of Daqing 0# diesel and could reduce the cold filter plugging point of Daqing 0# diesel by 7~8℃.
2006, 23(12): 1396-1400
Abstract:
Nanosized gas sensing material SnO2 was synthesized through pyrolysis of an oxalate precursor at different temperatures.The SnO2 samples were characterized by means of XRD,IR and gas sensing testing.The results reveal that at different pyrolysis temperatures,the SnO2 particles obtained show different grain sizes.The results indicate that the mechanism for SnO2 crystal growth was different when the pyrolysis temperature was below or above 650℃.The grain size of SnO2 increased slowly with pyrolysis temperature up to 650℃,where surface diffusion was dominant,while at above 650℃,grains began to grow via crystal boundary migration,and grew rapidly.Sensitivity of nanosized gas sensing material SnO2 is greatly affected by pyrolyzing temperature,while response and recovery time is relatively stable.SnO2 obtained at 650℃ exhibits the best sensitive properties.
Nanosized gas sensing material SnO2 was synthesized through pyrolysis of an oxalate precursor at different temperatures.The SnO2 samples were characterized by means of XRD,IR and gas sensing testing.The results reveal that at different pyrolysis temperatures,the SnO2 particles obtained show different grain sizes.The results indicate that the mechanism for SnO2 crystal growth was different when the pyrolysis temperature was below or above 650℃.The grain size of SnO2 increased slowly with pyrolysis temperature up to 650℃,where surface diffusion was dominant,while at above 650℃,grains began to grow via crystal boundary migration,and grew rapidly.Sensitivity of nanosized gas sensing material SnO2 is greatly affected by pyrolyzing temperature,while response and recovery time is relatively stable.SnO2 obtained at 650℃ exhibits the best sensitive properties.
2006, 23(12): 1401-1403
Abstract:
5-chloromethyl-2-oxazolidinone was prepared in a yield of 75.2% by the reaction of epichlorohydrin,sodium cyanate and magnesium sulfate(molar ratio,1:2:2) in water(10 mL/g epichlorohydrin) at 90~95℃ for 1.5 h.The phenols were first converted to sodium phenolate by the reaction of phenol and sodium hydroxide in methanol,then 5-(aryloxymethyl)-2-oxazolidinones were synthesized in 65%~80% yields by the reaction of sodium phenolate and 5-chloromethyl-2-oxazolidinone(molar ratio,1:1) in DMSO at 150℃ for 3 h.Title compounds were characterized by means of 1H NMR,IR and elemental analysis.
5-chloromethyl-2-oxazolidinone was prepared in a yield of 75.2% by the reaction of epichlorohydrin,sodium cyanate and magnesium sulfate(molar ratio,1:2:2) in water(10 mL/g epichlorohydrin) at 90~95℃ for 1.5 h.The phenols were first converted to sodium phenolate by the reaction of phenol and sodium hydroxide in methanol,then 5-(aryloxymethyl)-2-oxazolidinones were synthesized in 65%~80% yields by the reaction of sodium phenolate and 5-chloromethyl-2-oxazolidinone(molar ratio,1:1) in DMSO at 150℃ for 3 h.Title compounds were characterized by means of 1H NMR,IR and elemental analysis.
2006, 23(12): 1404-1406
Abstract:
Small molecule coralyne was found to bind preferentially and strongly to RNA in triple helical state.The binding was characterized by means of circular dichroism,fluorescence spectroscopy,thermal denaturation and competition dialysis assay.The binding constant(Kapp) is (2.0±0.4)×106(mol/L)-1,and the melting temperature of polyA(polyU)2 can be increased by coralyne for about 11℃.
Small molecule coralyne was found to bind preferentially and strongly to RNA in triple helical state.The binding was characterized by means of circular dichroism,fluorescence spectroscopy,thermal denaturation and competition dialysis assay.The binding constant(Kapp) is (2.0±0.4)×106(mol/L)-1,and the melting temperature of polyA(polyU)2 can be increased by coralyne for about 11℃.
2006, 23(12): 1407-1409
Abstract:
The [Dy(4-FBA)3·2,2'-bpy]2 complex was synthesized from 4-fluorobenzoic acid(4-HFBA),2,2'-bipyridine(2,2'-bpy) and DyCl3·6H2O.The crystal structure of the complex was determined by means of X-ray diffraction method.The complex crystallized into triclinic crystals with P1 symmetry and the unit cell parameters are a=1.041 75(15) nm,b=1.067 30(15) nm,c=1.361 57(19) nm,α=106.030(2)°,β=99.256(2)°,γ=95.949(2)°.M=735.99,V=1.418 5(3) nm3,Z=2,Dcalc=1.723 mg/m3,F(000)=722.The two Dy3+ ions are bonded to four oxygen atoms from 4-fluorobenzoic acid,forming a binuclear molecule.The coordination number of the metal ion is eight.The complex exhibits photoluminescent emission peaks at 481 nm and 575 nm,corresponding to the transitions of the Dy3+ ion:4F9/2→6H15/2 and 4F9/2→6H13/2.
The [Dy(4-FBA)3·2,2'-bpy]2 complex was synthesized from 4-fluorobenzoic acid(4-HFBA),2,2'-bipyridine(2,2'-bpy) and DyCl3·6H2O.The crystal structure of the complex was determined by means of X-ray diffraction method.The complex crystallized into triclinic crystals with P1 symmetry and the unit cell parameters are a=1.041 75(15) nm,b=1.067 30(15) nm,c=1.361 57(19) nm,α=106.030(2)°,β=99.256(2)°,γ=95.949(2)°.M=735.99,V=1.418 5(3) nm3,Z=2,Dcalc=1.723 mg/m3,F(000)=722.The two Dy3+ ions are bonded to four oxygen atoms from 4-fluorobenzoic acid,forming a binuclear molecule.The coordination number of the metal ion is eight.The complex exhibits photoluminescent emission peaks at 481 nm and 575 nm,corresponding to the transitions of the Dy3+ ion:4F9/2→6H15/2 and 4F9/2→6H13/2.
2006, 23(12): 1410-1412
Abstract:
Support vector machine(SVM) was employed in quantitative structure-property relationship(QSPR) study for analyzing the refractive indices(n) of 95 high molecular weight polymers.Comparisons was systematically made based on the results obtained with different methods of multiple linear regression(MLR),artificial neural network(ANN) and ones reported in literatures.It is suggested that SVM possesses both high modeling stability and good generalization ability,especially when applied to investigating both nonlinear systems and small samplings,yielding superior modeling results.The cumulative multiple correlation coefficient r2,cumulative cross-validated q2 and external qext2 are 0.943,0.938 and 0.919, respectively.Therefore it is believed that SVM has broad prospects and wide applications for the evaluation of polymer properties.
Support vector machine(SVM) was employed in quantitative structure-property relationship(QSPR) study for analyzing the refractive indices(n) of 95 high molecular weight polymers.Comparisons was systematically made based on the results obtained with different methods of multiple linear regression(MLR),artificial neural network(ANN) and ones reported in literatures.It is suggested that SVM possesses both high modeling stability and good generalization ability,especially when applied to investigating both nonlinear systems and small samplings,yielding superior modeling results.The cumulative multiple correlation coefficient r2,cumulative cross-validated q2 and external qext2 are 0.943,0.938 and 0.919, respectively.Therefore it is believed that SVM has broad prospects and wide applications for the evaluation of polymer properties.
2006, 23(12): 1413-1415
Abstract:
Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride in the presence of a biomolecule(HPMC) as the template.The products were characterized by SEM,FT-IR and XRD,respectively.The results show that calcite formed in the absence of HPMC and vaterite formed in the presence of HPMC.The effect of HPMC on the crystal form and morphology of the as-prepared CaCO3 was investigated.It was found that the shape of the produced calcium carbonate crystallites could be well controlled by adjusting the HPMC concentration.Vaterite spheres were induced when the ω(HPMC) reached 1.0%.
Spherical calcium carbonate was prepared by the reaction of sodium carbonate with calcium chloride in the presence of a biomolecule(HPMC) as the template.The products were characterized by SEM,FT-IR and XRD,respectively.The results show that calcite formed in the absence of HPMC and vaterite formed in the presence of HPMC.The effect of HPMC on the crystal form and morphology of the as-prepared CaCO3 was investigated.It was found that the shape of the produced calcium carbonate crystallites could be well controlled by adjusting the HPMC concentration.Vaterite spheres were induced when the ω(HPMC) reached 1.0%.
2006, 23(12): 1416-1418
Abstract:
Two cyclopropyl spiro thiobarbiturs with rigid configurations were designed,synthesized and characterized by IR and NMR.The difference in the chemical shift of N-H between compounds 1a and 1b was observed.The rigid structure was also proved by the relation between the proton (-CH2-) in the cyclopropane ring and the nearest proton (N-H) in the bartitur ring on 1H-1H COSY map due to the shielding effect of the two rings.The anticonvulsion activities of the two novel compounds 1a and 1b were also tested and the restrain ratio was 50% and 70% respectively.
Two cyclopropyl spiro thiobarbiturs with rigid configurations were designed,synthesized and characterized by IR and NMR.The difference in the chemical shift of N-H between compounds 1a and 1b was observed.The rigid structure was also proved by the relation between the proton (-CH2-) in the cyclopropane ring and the nearest proton (N-H) in the bartitur ring on 1H-1H COSY map due to the shielding effect of the two rings.The anticonvulsion activities of the two novel compounds 1a and 1b were also tested and the restrain ratio was 50% and 70% respectively.
2006, 23(12): 1419-1421
Abstract:
Two key intermediates toward tylophorine,2,3,6,7-tetramethoxyphenanthrene-9carboxylic acid(6a) and 2,3,6,7-tetramethoxy-9-cyanophenanthrene(6b),were prepared from(E)-2,3-bis(3,4-dimethoxyphenyl)acrylic acid(5a) and (Z)-2,3-bis(3,4-dimethoxyphenyl) acrylonitrile(5b),under the catalysis of(phenyliodine) diacetate(PIDA,2).Their yields were 65.83% and 64.76% respectively.Their structures were characterized by means of 1H NMR.
Two key intermediates toward tylophorine,2,3,6,7-tetramethoxyphenanthrene-9carboxylic acid(6a) and 2,3,6,7-tetramethoxy-9-cyanophenanthrene(6b),were prepared from(E)-2,3-bis(3,4-dimethoxyphenyl)acrylic acid(5a) and (Z)-2,3-bis(3,4-dimethoxyphenyl) acrylonitrile(5b),under the catalysis of(phenyliodine) diacetate(PIDA,2).Their yields were 65.83% and 64.76% respectively.Their structures were characterized by means of 1H NMR.
2006, 23(12): 1422-1424
Abstract:
3β-Hydroxyandrost-4-en-6,17-dione(3-OHAT),a non-androgenic aromatase inhibitor,was synthesized via a new process.With dehydroepiandrosterone acetate as starting material,the synthetic procedure included five steps: epoxidation of C=C bond with performic acid,ring opening of the epoxide with periodic acid,oxidation of 6-hydroxy by IBX,elimination of H2O and hydrolysis of the ester.The total yield was up to 55%.The use of performic acid,an affordable and easily prepared reagent,in epoxidation led to quantitatively the target epoxide.The oxidation of the 1,2-diol by IBX provided the oxidative product with a high yield of 98.5%,moreover,the introduction of IBX avoided the use of chromic reagent,which leads to the tedious work-up for the product purification and environmental pollution.
3β-Hydroxyandrost-4-en-6,17-dione(3-OHAT),a non-androgenic aromatase inhibitor,was synthesized via a new process.With dehydroepiandrosterone acetate as starting material,the synthetic procedure included five steps: epoxidation of C=C bond with performic acid,ring opening of the epoxide with periodic acid,oxidation of 6-hydroxy by IBX,elimination of H2O and hydrolysis of the ester.The total yield was up to 55%.The use of performic acid,an affordable and easily prepared reagent,in epoxidation led to quantitatively the target epoxide.The oxidation of the 1,2-diol by IBX provided the oxidative product with a high yield of 98.5%,moreover,the introduction of IBX avoided the use of chromic reagent,which leads to the tedious work-up for the product purification and environmental pollution.
