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2018 Volume 35 Issue 10
2018, 35(10): 1155-1165
doi: 10.11944/j.issn.1000-0518.2018.10.170461
Abstract:
Fluorescent probes as a major discovery in the field of chemical sensing at the end of the 20th century have the advantages of simple synthesis, high sensitivity, good selectivity, short response time and high visualization. The combination of the fluorescent group with the aggregation-induced emission(AIE) characteristics and the biocompatible polymer makes the fluorescent materials have the characteristics of low toxicity, good light stability and good biocompatibility. In molecular, ion detection and cell imaging technology it has been widely studied and applied. This review summarizes the fluorescence probes for cytoplasmic imaging, cell membrane imaging, mitochondrial imaging, lysosomal imaging, lipid droplet imaging, nuclear imaging, nuclear and mitochondrial dual-targeting imaging and the prospects for their application.
Fluorescent probes as a major discovery in the field of chemical sensing at the end of the 20th century have the advantages of simple synthesis, high sensitivity, good selectivity, short response time and high visualization. The combination of the fluorescent group with the aggregation-induced emission(AIE) characteristics and the biocompatible polymer makes the fluorescent materials have the characteristics of low toxicity, good light stability and good biocompatibility. In molecular, ion detection and cell imaging technology it has been widely studied and applied. This review summarizes the fluorescence probes for cytoplasmic imaging, cell membrane imaging, mitochondrial imaging, lysosomal imaging, lipid droplet imaging, nuclear imaging, nuclear and mitochondrial dual-targeting imaging and the prospects for their application.
2018, 35(10): 1166-1173
doi: 10.11944/j.issn.1000-0518.2018.10.180123
Abstract:
Due to the novel structural and interfacial characteristics, two-dimensional(2D) layered are nanomaterials awarded unique properties in transdermal absorption, sunscreen, active targeting delivery, and stable nanocapsules with great advantage in cosmetics industry. According to different layered charges, the typical 2D layered nanomaterials involve cationic and anionic clays(such as hydratalcite). Based on recent development in this field, this article reviews the characteristics and performance of 2D nanomaterials, particularly on history, current situation and market prospect in cosmetics application.
Due to the novel structural and interfacial characteristics, two-dimensional(2D) layered are nanomaterials awarded unique properties in transdermal absorption, sunscreen, active targeting delivery, and stable nanocapsules with great advantage in cosmetics industry. According to different layered charges, the typical 2D layered nanomaterials involve cationic and anionic clays(such as hydratalcite). Based on recent development in this field, this article reviews the characteristics and performance of 2D nanomaterials, particularly on history, current situation and market prospect in cosmetics application.
2018, 35(10): 1174-1183
doi: 10.11944/j.issn.1000-0518.2018.10.170365
Abstract:
In order to explore the influence of methoxy substitution in benzene ring, methylation of tyramine hydroxyl and cinnamoyl-tyramine amines, on anti-platelet aggregation activities analogues, cinnamoyl-tyramine amide analogues were synthesized via condensation and methylation with eight benzaldehyde derivatives as raw materials. The structures of synthesized compounds were characterized by nuclear magnetic resonance spectroscopy(NMR), mass spectrometry(MS) and single crystal diffraction. Based on variable-temperature NMR, rotational isomerization based on amide C-N bond was studied for compounds 4a~4h. Their anti-platelet aggregation activities were tested in vitro and assayed by Born test. The results show that nine analogues are more active than podocarpamide. Specifically, compounds 2c, 4c and 4f show inhibition rates of 50.03%, 60.87% and 53.33%, respectively, at 200 μmol/L. The preliminary structure-activity relationship studies on these compounds indicate that 4-methoxy substituent is the most favorable for anti-ADP(adenosine-diphosphate) induced platelet aggregation, and methylated hydroxyl group on ring B and the amide nitrogen also increase the activities to some extent.
In order to explore the influence of methoxy substitution in benzene ring, methylation of tyramine hydroxyl and cinnamoyl-tyramine amines, on anti-platelet aggregation activities analogues, cinnamoyl-tyramine amide analogues were synthesized via condensation and methylation with eight benzaldehyde derivatives as raw materials. The structures of synthesized compounds were characterized by nuclear magnetic resonance spectroscopy(NMR), mass spectrometry(MS) and single crystal diffraction. Based on variable-temperature NMR, rotational isomerization based on amide C-N bond was studied for compounds 4a~4h. Their anti-platelet aggregation activities were tested in vitro and assayed by Born test. The results show that nine analogues are more active than podocarpamide. Specifically, compounds 2c, 4c and 4f show inhibition rates of 50.03%, 60.87% and 53.33%, respectively, at 200 μmol/L. The preliminary structure-activity relationship studies on these compounds indicate that 4-methoxy substituent is the most favorable for anti-ADP(adenosine-diphosphate) induced platelet aggregation, and methylated hydroxyl group on ring B and the amide nitrogen also increase the activities to some extent.
2018, 35(10): 1184-1189
doi: 10.11944/j.issn.1000-0518.2018.10.170406
Abstract:
4-Hydroxylcoumarin and its analogs are one of the most active classes of heterocyclic compounds. Many of these compounds have been proved to have a wide range of biological and pharmacological activities, such as antibacterial, anti-tumor, anti-HIV. Herein, 3-arylthio-4-hydroxycoumarin and its analogs were synthesized from stable non-toxic 4-hydroxycoumarins, iodobenzenes and sulfur in a cheap and environmentally friendly fashion.
4-Hydroxylcoumarin and its analogs are one of the most active classes of heterocyclic compounds. Many of these compounds have been proved to have a wide range of biological and pharmacological activities, such as antibacterial, anti-tumor, anti-HIV. Herein, 3-arylthio-4-hydroxycoumarin and its analogs were synthesized from stable non-toxic 4-hydroxycoumarins, iodobenzenes and sulfur in a cheap and environmentally friendly fashion.
2018, 35(10): 1190-1200
doi: 10.11944/j.issn.1000-0518.2018.10.170352
Abstract:
Boron trifluoride diethyl etherate(BF3·OEt2)catalyzed reaction of 2-(N-substituted amino)benzyl alcohol with aldehyde was studied, and resulted a new method for the preparation of substituted 3, 1-benzoxazine. By this method, a series of novel 1-(carbamoylmethyl)-2-aryl/alkyl-3, 1-benzoxazines was prepared. It was found that BF3·OEt2 was a more general catalyst for these reactions than chlorotrimethylsilane and SnCl4 for the reaction and the reason causing this difference was discussed.
Boron trifluoride diethyl etherate(BF3·OEt2)catalyzed reaction of 2-(N-substituted amino)benzyl alcohol with aldehyde was studied, and resulted a new method for the preparation of substituted 3, 1-benzoxazine. By this method, a series of novel 1-(carbamoylmethyl)-2-aryl/alkyl-3, 1-benzoxazines was prepared. It was found that BF3·OEt2 was a more general catalyst for these reactions than chlorotrimethylsilane and SnCl4 for the reaction and the reason causing this difference was discussed.
2018, 35(10): 1201-1207
doi: 10.11944/j.issn.1000-0518.2018.10.170393
Abstract:
Catalytic one-pot four-component reaction is an ideal strategy for efficient and facile synthesis of pyrano[2, 3-c]pyrazoles. The efficacy of dipotassium hydrogenphosphate(K2HPO4·3H2O) as a cheap and readily accessible catalyst for the synthesis of 1, 4-dihydropyrano[2, 3-c]pyrazole-5-carbonitrile derivatives via one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, aryl aldehydes, and malononitrile was described in this paper. These multi-component condensations proceeded smoothly in aqueous polyethylene glycol(PEG-200) and the corresponding products were obtained in 88%~98% yields. This improved protocol eliminates the problems associated with expensive complex catalyst and tedious purification procedures.
Catalytic one-pot four-component reaction is an ideal strategy for efficient and facile synthesis of pyrano[2, 3-c]pyrazoles. The efficacy of dipotassium hydrogenphosphate(K2HPO4·3H2O) as a cheap and readily accessible catalyst for the synthesis of 1, 4-dihydropyrano[2, 3-c]pyrazole-5-carbonitrile derivatives via one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, aryl aldehydes, and malononitrile was described in this paper. These multi-component condensations proceeded smoothly in aqueous polyethylene glycol(PEG-200) and the corresponding products were obtained in 88%~98% yields. This improved protocol eliminates the problems associated with expensive complex catalyst and tedious purification procedures.
2018, 35(10): 1208-1214
doi: 10.11944/j.issn.1000-0518.2018.10.170370
Abstract:
Glucose responsive gel fibers have potential application prospects in the development of glucose sensors for monitoring blood glucose levels. In this work, poly(N-ispropylacrylamide/3-acrylamidophenylboronic acid)(P(NIPAM-co-AAPBA)) glucose sensitive hydrogel fibers were fabricated via microfluidic spinning and off-chip free radical polymerization reaction. The structure and morphology, mechanical properties, swelling kinetics and glucose responsiveness of the gel fibers were characterized by Fourier transform infrared spectrometer(FTIR), scanning electron microscopy(SEM) and mechanical test. The results show that the gel fibers have porous microstructures, and their diameters could be controlled by changing the flow rates of the core and sheath layer solution. With the increase of AAPBA mass fraction, the swelling rate and equilibrium swelling degree of the gel fibers are decreased, but the glucose response performance is improved. Compared with the chemically cross-linked gel fibers, the physically cross-linked gel fibers have good mechanical properties.
Glucose responsive gel fibers have potential application prospects in the development of glucose sensors for monitoring blood glucose levels. In this work, poly(N-ispropylacrylamide/3-acrylamidophenylboronic acid)(P(NIPAM-co-AAPBA)) glucose sensitive hydrogel fibers were fabricated via microfluidic spinning and off-chip free radical polymerization reaction. The structure and morphology, mechanical properties, swelling kinetics and glucose responsiveness of the gel fibers were characterized by Fourier transform infrared spectrometer(FTIR), scanning electron microscopy(SEM) and mechanical test. The results show that the gel fibers have porous microstructures, and their diameters could be controlled by changing the flow rates of the core and sheath layer solution. With the increase of AAPBA mass fraction, the swelling rate and equilibrium swelling degree of the gel fibers are decreased, but the glucose response performance is improved. Compared with the chemically cross-linked gel fibers, the physically cross-linked gel fibers have good mechanical properties.
2018, 35(10): 1215-1221
doi: 10.11944/j.issn.1000-0518.2018.10.170354
Abstract:
In order to reduce the vibration and air noise of ship deck, damping polyurethane was prepared from branched and linear polyols and low viscosity polymethylene polyphrnyl polyisocyanate(PMDI), and laid between steel deck and floating deck. The effects of matrix structure and damping filler on the curing time, leveling, damping and mechanical properties of damping layer were studied. The sound insulation performance of decks before and after laying damping layer was discussed. The results show that adjusting the mass ratio of branched and linear polyols can change the degree of crosslinking and the structure of the matrix. Branched polyols improve the cure rate, hardness, and mechanical properties. Linear polyols reduce the glass transition temperature of the system. The damping temperature range appears at high temperature and the loss factor peak value increases. A two-milimeter-thick polyurethane damping layer under an existing floating deck structure effectively increases the average sound insulation by 3 dB, and the effect is greater in the low frequency range. The polyurethane damping layer has excellent fluidity, controllable curing time and convenient self-leveling construction, which is of practical significance for improving the sound reduction performance of the existing floating deck.
In order to reduce the vibration and air noise of ship deck, damping polyurethane was prepared from branched and linear polyols and low viscosity polymethylene polyphrnyl polyisocyanate(PMDI), and laid between steel deck and floating deck. The effects of matrix structure and damping filler on the curing time, leveling, damping and mechanical properties of damping layer were studied. The sound insulation performance of decks before and after laying damping layer was discussed. The results show that adjusting the mass ratio of branched and linear polyols can change the degree of crosslinking and the structure of the matrix. Branched polyols improve the cure rate, hardness, and mechanical properties. Linear polyols reduce the glass transition temperature of the system. The damping temperature range appears at high temperature and the loss factor peak value increases. A two-milimeter-thick polyurethane damping layer under an existing floating deck structure effectively increases the average sound insulation by 3 dB, and the effect is greater in the low frequency range. The polyurethane damping layer has excellent fluidity, controllable curing time and convenient self-leveling construction, which is of practical significance for improving the sound reduction performance of the existing floating deck.
2018, 35(10): 1222-1226
doi: 10.11944/j.issn.1000-0518.2018.10.170355
Abstract:
The unsaturated polyester resin sheet molding compound(UP-SMC) products were prepared by compression molding. The mechanical properties, thermal stability and flame retardant performance of UP-SMC products were characterized by the universal testing machine, thermogravimetric analysis, dynamic mechanical analysis, limiting oxygen index and nanoindentation technology. The results show that the bending strength and impact strength of UP-SMC products are up to 203.4 and 94.2 MPa, respectively, and the micromechanical properties are different from resin to fiber phases. The glass transition temperature is 169.4℃, the temperature at 5% mass loss(Td5) and maximum mass loss rate(Tdmax) are 333.5 and 389.7℃, respectively. The residue at 600℃ is up to 75%, but the limiting oxygen index is only 25.7%, indicting that the prepared UP-SMC products have excellent mechanical and thermal stability properties.
The unsaturated polyester resin sheet molding compound(UP-SMC) products were prepared by compression molding. The mechanical properties, thermal stability and flame retardant performance of UP-SMC products were characterized by the universal testing machine, thermogravimetric analysis, dynamic mechanical analysis, limiting oxygen index and nanoindentation technology. The results show that the bending strength and impact strength of UP-SMC products are up to 203.4 and 94.2 MPa, respectively, and the micromechanical properties are different from resin to fiber phases. The glass transition temperature is 169.4℃, the temperature at 5% mass loss(Td5) and maximum mass loss rate(Tdmax) are 333.5 and 389.7℃, respectively. The residue at 600℃ is up to 75%, but the limiting oxygen index is only 25.7%, indicting that the prepared UP-SMC products have excellent mechanical and thermal stability properties.
2018, 35(10): 1227-1233
doi: 10.11944/j.issn.1000-0518.2018.10.170333
Abstract:
A kind of liquid crystal emulsion was prepared with lecithin as the main emulsifier. The emulsion has good stability on the skin. The whole liquid crystal structure can be maintained for 6 hours on the surface of skin. It overcomes the problem that liquid crystal texture cannot stay on the skin for a long time in general liquid crystal emulsion. Liquid crystal structure has a high stability near skin temperature. It can provide conditions for other performances of liquid crystal emulsion. The water locking properties of different emulsions are measured by in vitro weighing method and the water locking property of liquid crystal emulsion is better than that of traditional emulsion. There are still fifty percent of the total water contents after 7 h. The results of dialysis experiments in vitro confirm that the liquid crystal emulsion has a remarkable slow-release property and can be released completely. The release ratio of target molecule is up to 96% after 7 h. It also shows that liquid crystal emulsion has excellent temperature resistance and low temperature freeze-thaw properties. The effect of temperature on the lamellar liquid crystals in emulsion is recoverable. The storage and transportation stability of emulsion is studied by the centrifugal method, high and low temperature cycle and placement under high and low temperature for 3 months. It shows that liquid crystal emulsion products have excellent storage and transportation stability. It is convenient for practical application and storage and transportation. The study not only provides necessary information and reference data for the development of multi-effect upmarket cosmetics, but also expands the application category of lecithin liquid crystal emulsifier system.
A kind of liquid crystal emulsion was prepared with lecithin as the main emulsifier. The emulsion has good stability on the skin. The whole liquid crystal structure can be maintained for 6 hours on the surface of skin. It overcomes the problem that liquid crystal texture cannot stay on the skin for a long time in general liquid crystal emulsion. Liquid crystal structure has a high stability near skin temperature. It can provide conditions for other performances of liquid crystal emulsion. The water locking properties of different emulsions are measured by in vitro weighing method and the water locking property of liquid crystal emulsion is better than that of traditional emulsion. There are still fifty percent of the total water contents after 7 h. The results of dialysis experiments in vitro confirm that the liquid crystal emulsion has a remarkable slow-release property and can be released completely. The release ratio of target molecule is up to 96% after 7 h. It also shows that liquid crystal emulsion has excellent temperature resistance and low temperature freeze-thaw properties. The effect of temperature on the lamellar liquid crystals in emulsion is recoverable. The storage and transportation stability of emulsion is studied by the centrifugal method, high and low temperature cycle and placement under high and low temperature for 3 months. It shows that liquid crystal emulsion products have excellent storage and transportation stability. It is convenient for practical application and storage and transportation. The study not only provides necessary information and reference data for the development of multi-effect upmarket cosmetics, but also expands the application category of lecithin liquid crystal emulsifier system.
2018, 35(10): 1234-1242
doi: 10.11944/j.issn.1000-0518.2018.10.170349
Abstract:
Polyethyleneimine(PEI) and its emulsions have been widely used in enzyme immobilization, gene therapy and waste water treatment, etc. In this work, a partial factorial test was employed to study the main factors and the interaction effect between various factors influencing the stability of water-in-oil(W/O) type PEI solution-in-paraffin emulsion. The results show that the amount of emulsifier and the mass fraction of PEI in aqueous phase are the main factors that influence the stability of the emulsion. The most significant factor is the interaction between the mass fraction of PEI in aqueous phase and the volume ratio of water/oil. The optimum conditions of the emulsion are:20% PEI in the aqueous phase, 0.07 g/mL of the emulsifier, 6:4 volume ratio of water/oil, 3 min of homogenization time and 6000 r/min of the homogenization velocity. The emulsion prepared under the optimal conditions has shown no significant changes of emulsification in a week, indicating its excellent stability.
Polyethyleneimine(PEI) and its emulsions have been widely used in enzyme immobilization, gene therapy and waste water treatment, etc. In this work, a partial factorial test was employed to study the main factors and the interaction effect between various factors influencing the stability of water-in-oil(W/O) type PEI solution-in-paraffin emulsion. The results show that the amount of emulsifier and the mass fraction of PEI in aqueous phase are the main factors that influence the stability of the emulsion. The most significant factor is the interaction between the mass fraction of PEI in aqueous phase and the volume ratio of water/oil. The optimum conditions of the emulsion are:20% PEI in the aqueous phase, 0.07 g/mL of the emulsifier, 6:4 volume ratio of water/oil, 3 min of homogenization time and 6000 r/min of the homogenization velocity. The emulsion prepared under the optimal conditions has shown no significant changes of emulsification in a week, indicating its excellent stability.
2018, 35(10): 1243-1248
doi: 10.11944/j.issn.1000-0518.2018.10.170342
Abstract:
Extensive molecular dynamics simulations were performed to study the distribution and dynamics of water and urea in the hydration shell of ribonuclease Sa(RNase Sa) under different urea concentrations. It is found that urea molecules have stronger interactions with protein than water molecules and are enriched on the surface of RNase Sa by displacing water molecules. Urea molecules prefer to interact with hydrophobic residues and form hydrogen bonds with the backbone of RNase Sa. The transitional and rotational dynamics of urea molecules are much slower than those of water molecules. Besides, the increased urea concentrations can slow down the transitional and rotational dynamics of water molecules, but have no regular influences on the dynamics of urea molecules. Our results can help understanding the different influences of urea and water molecules on the stability of proteins.
Extensive molecular dynamics simulations were performed to study the distribution and dynamics of water and urea in the hydration shell of ribonuclease Sa(RNase Sa) under different urea concentrations. It is found that urea molecules have stronger interactions with protein than water molecules and are enriched on the surface of RNase Sa by displacing water molecules. Urea molecules prefer to interact with hydrophobic residues and form hydrogen bonds with the backbone of RNase Sa. The transitional and rotational dynamics of urea molecules are much slower than those of water molecules. Besides, the increased urea concentrations can slow down the transitional and rotational dynamics of water molecules, but have no regular influences on the dynamics of urea molecules. Our results can help understanding the different influences of urea and water molecules on the stability of proteins.
2018, 35(10): 1249-1255
doi: 10.11944/j.issn.1000-0518.2018.10.170356
Abstract:
A novel complex, [Mn(C7H5N4)·(SO4)·2H2O](1), was synthesized by hydrothermal reaction of organic ligand 2-(1H-1, 2, 4-triazol-3-yl)pyridine(2-HTP) with MnSO4·H2O in ethanol aqueous solution. The analysis and characterization of complex 1 were obtained via elemental analysis, infrared(IR), X-ray single-crystal diffraction, solid fluorescence analysis, and thermogravimetric analysis(TGA). Crystal data of complex 1 at 297 K are:monoclinic, P21/n, a=1.16373(12) nm, b=0.79324(9) nm, c=1.40241(15) nm, V=1.1996(2) nm3, Z=4. Crystal structure analysis indicates that 2-HTPs, as bidentate ligands, coordinate to Mn2+ that links to two water molecules and SO42- by bridge connection into one-dimensional chain complex. In addition, there are π-π stacking between the aromatic-ring of 2-HTPs. Solid fluorescence analysis reveals that complex 1 shows blue fluorescence property with a strong emission at 477 nm.
A novel complex, [Mn(C7H5N4)·(SO4)·2H2O](1), was synthesized by hydrothermal reaction of organic ligand 2-(1H-1, 2, 4-triazol-3-yl)pyridine(2-HTP) with MnSO4·H2O in ethanol aqueous solution. The analysis and characterization of complex 1 were obtained via elemental analysis, infrared(IR), X-ray single-crystal diffraction, solid fluorescence analysis, and thermogravimetric analysis(TGA). Crystal data of complex 1 at 297 K are:monoclinic, P21/n, a=1.16373(12) nm, b=0.79324(9) nm, c=1.40241(15) nm, V=1.1996(2) nm3, Z=4. Crystal structure analysis indicates that 2-HTPs, as bidentate ligands, coordinate to Mn2+ that links to two water molecules and SO42- by bridge connection into one-dimensional chain complex. In addition, there are π-π stacking between the aromatic-ring of 2-HTPs. Solid fluorescence analysis reveals that complex 1 shows blue fluorescence property with a strong emission at 477 nm.
2018, 35(10): 1256-1263
doi: 10.11944/j.issn.1000-0518.2018.10.170360
Abstract:
A new complex Eu(L)(MeOH)(NO3)3 was designed and synthesized under the hydrothermal reaction condition using Eu(NO3)3·6H2O as the metal source and 2, 6-bis(5-phenyl-1H-pyrazol-3-yl) pyridine (L) as the ligand, and characterized by elemental analysis, infrared spectra, thermogravimetric analysis, X-ray powder diffraction and X-ray single crystal diffraction. The structural analysis shows that the central metal of complex is nine-coordinated and each of the central metal europium atoms is coordinated with three nitrogen atoms from L, six oxygen atoms from NO3- ions and MeOH to form a slightly distorted three-cap triangular prismatic spatial configuration. It is found that the complex has a strong fluorescence quenching effect on copper and nickel ions. The presence of other competing metal ions does not interfere with selective detection of Cu2+ by the complex, but has certain effect on the selective detection of Ni2+.
A new complex Eu(L)(MeOH)(NO3)3 was designed and synthesized under the hydrothermal reaction condition using Eu(NO3)3·6H2O as the metal source and 2, 6-bis(5-phenyl-1H-pyrazol-3-yl) pyridine (L) as the ligand, and characterized by elemental analysis, infrared spectra, thermogravimetric analysis, X-ray powder diffraction and X-ray single crystal diffraction. The structural analysis shows that the central metal of complex is nine-coordinated and each of the central metal europium atoms is coordinated with three nitrogen atoms from L, six oxygen atoms from NO3- ions and MeOH to form a slightly distorted three-cap triangular prismatic spatial configuration. It is found that the complex has a strong fluorescence quenching effect on copper and nickel ions. The presence of other competing metal ions does not interfere with selective detection of Cu2+ by the complex, but has certain effect on the selective detection of Ni2+.
2018, 35(10): 1264-1270
doi: 10.11944/j.issn.1000-0518.2018.10.170454
Abstract:
Sodium titanate nanotube-carbon(STN-C) composites were prepared by a hydrothermal method using TiO2, NaOH solution and glucose as starting materials. X-ray diffraction(XRD) and transmission electron microscopy(TEM) were employed to characterize its crystal morphology. N2 adsorption-desorption and thermogravimetry(TG) methods were applied to confirm its pore structure and mass ratio of carbon. STN-C was adopted as negative electrode materials for the asymmetric electrochemical supercapatteries of STN-C/graphite using Na+-based organic electrolytes. This type of supercapatteries possess the working voltage as high as 3.5 V. The charge storage mechanism at the negative electrode was studied and the effect of mass ratio of graphite/STN-C was investigated. The electrochemical performance tests reveal that the supercapatteries have relatively high energy density and power density, i.e., 72 Wh/Kg and 1256 W/Kg, respectively. The supercapatteries also show high cycle stability, displaying a 100% capacity retention after 1000 cycles at a current density of 0.17 A/g.
Sodium titanate nanotube-carbon(STN-C) composites were prepared by a hydrothermal method using TiO2, NaOH solution and glucose as starting materials. X-ray diffraction(XRD) and transmission electron microscopy(TEM) were employed to characterize its crystal morphology. N2 adsorption-desorption and thermogravimetry(TG) methods were applied to confirm its pore structure and mass ratio of carbon. STN-C was adopted as negative electrode materials for the asymmetric electrochemical supercapatteries of STN-C/graphite using Na+-based organic electrolytes. This type of supercapatteries possess the working voltage as high as 3.5 V. The charge storage mechanism at the negative electrode was studied and the effect of mass ratio of graphite/STN-C was investigated. The electrochemical performance tests reveal that the supercapatteries have relatively high energy density and power density, i.e., 72 Wh/Kg and 1256 W/Kg, respectively. The supercapatteries also show high cycle stability, displaying a 100% capacity retention after 1000 cycles at a current density of 0.17 A/g.
2018, 35(10): 1271-1276
doi: 10.11944/j.issn.1000-0518.2018.10.170386
Abstract:
For the sake of convenient and quick detection of aluminum ion, an aluminum ion fluorescent chemosensor was synthesized from 7-hydroxyl coumarin. Its structure was verified by mass spectrometry and nuclear magnetic resonance spectrum. The properties and structure of fluorescence chemosensor were characterized by mass spectrometry(MS), nuclear magnetic resonance spectroscopy(NMR), UV-vsisible absorption spectrum(UV-Vis). The results reveal that the sensor has good selectivity toward aluminum ion. The limit of detection is 8.5×10-8 mol/L, and the identification process is reversible. The Job's plot indicates that the sensor and aluminum ion forms stable complex in 1:1 ratio. Therefore, this fluorescent chemosensor has potential in real time monitoring aluminum ion in biological and environmental applications.
For the sake of convenient and quick detection of aluminum ion, an aluminum ion fluorescent chemosensor was synthesized from 7-hydroxyl coumarin. Its structure was verified by mass spectrometry and nuclear magnetic resonance spectrum. The properties and structure of fluorescence chemosensor were characterized by mass spectrometry(MS), nuclear magnetic resonance spectroscopy(NMR), UV-vsisible absorption spectrum(UV-Vis). The results reveal that the sensor has good selectivity toward aluminum ion. The limit of detection is 8.5×10-8 mol/L, and the identification process is reversible. The Job's plot indicates that the sensor and aluminum ion forms stable complex in 1:1 ratio. Therefore, this fluorescent chemosensor has potential in real time monitoring aluminum ion in biological and environmental applications.
