In the past,most hydrogel composites of bone repair derived from either natural or chemical synthesis were lack of mechanical strength.So we used high strengthened PAA-Ch-Si hydrogel compounds and it containing PRP(pl...In the past,most hydrogel composites of bone repair derived from either natural or chemical synthesis were lack of mechanical strength.So we used high strengthened PAA-Ch-Si hydrogel compounds and it containing PRP(platelet-rich-plasma)material.They were prepared by UV light or y-ray irradiation method for scaffold material application in this paper.We exploited nanosized silica solution,natural chitosan and acrylic acid(AAc)as starting material to synthesize chitosan/hydrogel biomedical products.This biocompatible osteoconductive scaffold mixed with platelet glue to perform the biocompatibility tests for a composite bone graft material and be ap-展开更多
This paper investigates the properties of displacement sensors based on polyaniline （PANI） films. About 1 wt% of PANI micropowder is mixed and stirred in a solution of 90 wt% water and 10 wt% alcohol at room tempera...This paper investigates the properties of displacement sensors based on polyaniline （PANI） films. About 1 wt% of PANI micropowder is mixed and stirred in a solution of 90 wt% water and 10 wt% alcohol at room temperature. The films of PANI axe deposited from solution by drop-casting on Ag electrodes, which are preliminary deposited on glass substrates. The thicknesses of the PANI films are in the range of 20 μm-80 μm. A displacement sensor with polyaniline film as an active material is designed and fabricated. The investigations showed that, on average, the AC resistance of the sensor decreases by 2 times and the capacitance accordingly increases by 1.6 times as the displacement changes in the range of 0 mm-0.5 mm. The polyaniline is the only active material of the displacement sensor. The resistance and capacitance of the PANI changes under the pressure of spring and elastic rubber, and this pressure is created by the downward movement of the micrometer.展开更多
A new technique-series electro-pulse discharg e (SEPD)-was developed as a kind of surface coating process. In this technique, both positive and negative poles of a pulse power were used as the depositing electrodes...A new technique-series electro-pulse discharg e (SEPD)-was developed as a kind of surface coating process. In this technique, both positive and negative poles of a pulse power were used as the depositing electrodes with the substrate allo y as an induction electrode. Micro-crystalline Co-Cr and Co-Cr dispersed wit h Y 2O 3 coatings were deposited on Fe-18Cr-8Ni stainless steel surface by using Co30Cr alloy as the depositing electrodes. Oxidation at 950 ℃ in ambie nt air shows that these coatings greatly improve the oxidation resistance of the steel. The addition of dispersed Y 2O 3 nano-particles into the alloy coati ngs was found to further reduce the scaling rate and enhance the adhesion of oxi de scales.展开更多
Polyaniline（PANI）/Ag nanocomposites, synthesized by incorporation of separately prepared silver nanoparticles in 1-methyl-2-pyrrolidinone（NMP） solution of PANI, have been aged at the accelerated temperature of 120...Polyaniline（PANI）/Ag nanocomposites, synthesized by incorporation of separately prepared silver nanoparticles in 1-methyl-2-pyrrolidinone（NMP） solution of PANI, have been aged at the accelerated temperature of 120℃ to simulate a storage period of 2 years at 25℃. The accelerated ageing of these materials is done by using the activation energy calculated from data collected using heat flow calorimetry （HFC）. The impedance spectroscopic studies of NMP plasticized aged nanocomposite films suggest a microphase separation into reduced and oxidized repeat units. There is crosslinking of the lPANI films during ageing thereby obstructing the charge transfer between PANI chains and silver nanoparticles. As a result, the resistivity is increased.展开更多
Three novel tri-dimensional phthalocyanine polymers, with lanthanum （LaPPc）, gadolinium （GdPPc） and ytterbium （YbPPc） as centric atoms, have been synthesized from a tetranuclear phthalonitrile. Third-order optic...Three novel tri-dimensional phthalocyanine polymers, with lanthanum （LaPPc）, gadolinium （GdPPc） and ytterbium （YbPPc） as centric atoms, have been synthesized from a tetranuclear phthalonitrile. Third-order optical nonlinearities of these compounds in DMF solution are measured by a picosecond Z-sacn technique at 532 nm. It is found that all the compounds show reverse saturation absorption and nonlinear self-focus refraction effect. The second-order molecular hyperpolarizabilities are calculated to be 1.82×10^-23, 1.48×10^-23 and 1.45×10^-23 esu for LaPPc, GdPPc and YbPPc, respectively. The differences among their nonlinear optical properties are attributed to the special tri-dimensional structure and the variation in rare earth atoms.展开更多
To prevent the thawing of ice-rich permafrost,it is suggested that gas should be transported in a chilled state(below the freezing temperature)in pipelines buried in permafrost.However,frost heave occurs when water mi...To prevent the thawing of ice-rich permafrost,it is suggested that gas should be transported in a chilled state(below the freezing temperature)in pipelines buried in permafrost.However,frost heave occurs when water migrates towards the chilled pipeline and ice lenses grow underneath the pipe.This might endanger the integrity of the pipeline and the environment as well.Therefore,innovative frost heave mitigation measures are required when designing the pipeline,especially those sections in discontinuous permafrost or near the compressor stations.The ground temperature field in response to the operation of a proposed chilled gas pipeline traversing permafrost regions in Alaska was simulated by a pipe-soil thermal interaction geothermal model.Frost heave mitigation measures,including insulation around the pipe,flat slab insulation under the pipe,and heating cables combined with slab insulation,were evaluated for chilled pipeline operation in seasonally varying ambient temperatures.The numerical results show that the minimum temperature of the observation point at 2.5 m below the pipe bottom increases by 17%,29%,and 48%when the thermal conductivity of the outer insulation layer is 0.1,0.05,and 0.02 W/(m K),respectively.For flat slab insulation,the thermal field is less sensitive to varying slab thicknesses than to varying thermal conductivity,implying the thermal conductivity,not the thickness,is the crucial factor.Additionally,the heat flow could be redirected from vertical to horizontal by flat slab insulation.The electrical heating cables could be regarded as a new heat source to balance the heat removal rate of the soil around the chilled pipe.The minimum temperature of the observation point at 1.1 m below the bottom of the pipe increases from-15.2℃to-3.0,1.5,and 7.5℃,corresponding to the heating cable power of 20,30,and 40 W,respectively,with the power of 30 W deemed appropriate for the study case.It is concluded that heating cables in combination with insulation slabs could be adopted to regulate the temperature field around the chilled pipeline efficiently and economically.The advantages of this combination include redirecting the heat flow and eliminating frost in the soil underlying the pipe.These approaches could be considered for applications in gas pipeline projects in arctic and alpine/high-plateau permafrost regions.展开更多
In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prom...In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.展开更多
In the present study, an enviro-friendly synthesis of silver nanoparticles from Berberis lycium Royle leaf extract and their antibacterial efficacy against five pathogenic bacteria were investigated. This biosynthesis...In the present study, an enviro-friendly synthesis of silver nanoparticles from Berberis lycium Royle leaf extract and their antibacterial efficacy against five pathogenic bacteria were investigated. This biosynthesis technique is proved to be advantageous over physical and chemical methods as no toxic chemicals are used. The structural and morphological characterization was made by UV-visible spectroscopy, scanning electron microscopy, and transmission electron microscopy. The synthesized nanoparticles were oval, rectangular, and spherical in shape, size ranges from 8 to 100 nm and exhibited an absorption peak at 458 nm. The biosynthesized silver nanoparticles have shown good antibacterial effect toward tested bacteria. It is believed that these biosynthesized silver nanoparticles can play a vital role in nano-based products in future.展开更多
We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide (TiO2) coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the so...We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide (TiO2) coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 (TiO2/cinder). Results show that the decolorization rate of Congo red solution was more than 98% after 2 h treatment when we used TiO2/cinder calcined at 500 °C for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.展开更多
Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature ph...Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature phase transformation. Electrochemical measurements showed that the nanohybrid anodes possessed enhanced reversible capacity and superior cycling stability compared to those of a pristine T-Nb205 nanowire electrode. Owing to the strong bonds between graphene nanosheets and T-Nb2O5 nanowires, the nanohybrids achieved an initial capacity of 227 mAh·g^-1. Additionally, non-aqueous asymmetric supercapacitors （ASCs） were fabricated with the synthesized nanohybrids as the anode and activated carbon as the cathode. The 3 V Li-ion ASC with a LiPF6-based organic electrolyte achieved an energy density of 45.1 Wh·kg^-1 at 715.2 W·kg^-1. The working potential could be further enhanced to 4 V when a polymer ionogel separator （PVDF-HFP/LiTFSI/EMIMBF4） and formulated ionic liquid electrolyte were employed. Such a quasi-solid state ASC could operate at 60℃ and delivered a maximum energy density of 70 Wh·kg^-1 at 1 kW·kg^-1.展开更多
文摘In the past,most hydrogel composites of bone repair derived from either natural or chemical synthesis were lack of mechanical strength.So we used high strengthened PAA-Ch-Si hydrogel compounds and it containing PRP(platelet-rich-plasma)material.They were prepared by UV light or y-ray irradiation method for scaffold material application in this paper.We exploited nanosized silica solution,natural chitosan and acrylic acid(AAc)as starting material to synthesize chitosan/hydrogel biomedical products.This biocompatible osteoconductive scaffold mixed with platelet glue to perform the biocompatibility tests for a composite bone graft material and be ap-
文摘This paper investigates the properties of displacement sensors based on polyaniline （PANI） films. About 1 wt% of PANI micropowder is mixed and stirred in a solution of 90 wt% water and 10 wt% alcohol at room temperature. The films of PANI axe deposited from solution by drop-casting on Ag electrodes, which are preliminary deposited on glass substrates. The thicknesses of the PANI films are in the range of 20 μm-80 μm. A displacement sensor with polyaniline film as an active material is designed and fabricated. The investigations showed that, on average, the AC resistance of the sensor decreases by 2 times and the capacitance accordingly increases by 1.6 times as the displacement changes in the range of 0 mm-0.5 mm. The polyaniline is the only active material of the displacement sensor. The resistance and capacitance of the PANI changes under the pressure of spring and elastic rubber, and this pressure is created by the downward movement of the micrometer.
基金financially supported by the National Natural Science Foundation of China(Nos.50472038 and 90606011)Program for New Century Excellent Talents in University(NCET-04-0588)the Excellent Youth Fund of Anhui Province(No.04044060).
文摘一篇小说(甲基 methacrylate-co-polyhedral oligomeric silsesquioxane ) poly，混合 nanocomposite 被自由基聚合综合并且描绘了由(1 ) H NMR，(29 ) Si NMR，和 TGA 技术。与 PMMA 人聚合物相比， nanocomposite 有更好的热稳定性。
文摘A new technique-series electro-pulse discharg e (SEPD)-was developed as a kind of surface coating process. In this technique, both positive and negative poles of a pulse power were used as the depositing electrodes with the substrate allo y as an induction electrode. Micro-crystalline Co-Cr and Co-Cr dispersed wit h Y 2O 3 coatings were deposited on Fe-18Cr-8Ni stainless steel surface by using Co30Cr alloy as the depositing electrodes. Oxidation at 950 ℃ in ambie nt air shows that these coatings greatly improve the oxidation resistance of the steel. The addition of dispersed Y 2O 3 nano-particles into the alloy coati ngs was found to further reduce the scaling rate and enhance the adhesion of oxi de scales.
文摘Polyaniline（PANI）/Ag nanocomposites, synthesized by incorporation of separately prepared silver nanoparticles in 1-methyl-2-pyrrolidinone（NMP） solution of PANI, have been aged at the accelerated temperature of 120℃ to simulate a storage period of 2 years at 25℃. The accelerated ageing of these materials is done by using the activation energy calculated from data collected using heat flow calorimetry （HFC）. The impedance spectroscopic studies of NMP plasticized aged nanocomposite films suggest a microphase separation into reduced and oxidized repeat units. There is crosslinking of the lPANI films during ageing thereby obstructing the charge transfer between PANI chains and silver nanoparticles. As a result, the resistivity is increased.
基金Supported by the National Natural Science General Foundation of China under Grant Nos 20773077, 20572059 and 20502013, the National Key Fundamental Research Programme of China under Grant No 2007CB808000, and the Postdoctoral Science Foundation of China under Grant No 20060390056.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20773077, 20572059 and 20502013, the National Key Fundamental Research Programme of China under Grant No 2007CB808000, and the Postdoctoral Science Foundation of China under Grant No 20060390056.
文摘Three novel tri-dimensional phthalocyanine polymers, with lanthanum （LaPPc）, gadolinium （GdPPc） and ytterbium （YbPPc） as centric atoms, have been synthesized from a tetranuclear phthalonitrile. Third-order optical nonlinearities of these compounds in DMF solution are measured by a picosecond Z-sacn technique at 532 nm. It is found that all the compounds show reverse saturation absorption and nonlinear self-focus refraction effect. The second-order molecular hyperpolarizabilities are calculated to be 1.82×10^-23, 1.48×10^-23 and 1.45×10^-23 esu for LaPPc, GdPPc and YbPPc, respectively. The differences among their nonlinear optical properties are attributed to the special tri-dimensional structure and the variation in rare earth atoms.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20100103).
文摘To prevent the thawing of ice-rich permafrost,it is suggested that gas should be transported in a chilled state(below the freezing temperature)in pipelines buried in permafrost.However,frost heave occurs when water migrates towards the chilled pipeline and ice lenses grow underneath the pipe.This might endanger the integrity of the pipeline and the environment as well.Therefore,innovative frost heave mitigation measures are required when designing the pipeline,especially those sections in discontinuous permafrost or near the compressor stations.The ground temperature field in response to the operation of a proposed chilled gas pipeline traversing permafrost regions in Alaska was simulated by a pipe-soil thermal interaction geothermal model.Frost heave mitigation measures,including insulation around the pipe,flat slab insulation under the pipe,and heating cables combined with slab insulation,were evaluated for chilled pipeline operation in seasonally varying ambient temperatures.The numerical results show that the minimum temperature of the observation point at 2.5 m below the pipe bottom increases by 17%,29%,and 48%when the thermal conductivity of the outer insulation layer is 0.1,0.05,and 0.02 W/(m K),respectively.For flat slab insulation,the thermal field is less sensitive to varying slab thicknesses than to varying thermal conductivity,implying the thermal conductivity,not the thickness,is the crucial factor.Additionally,the heat flow could be redirected from vertical to horizontal by flat slab insulation.The electrical heating cables could be regarded as a new heat source to balance the heat removal rate of the soil around the chilled pipe.The minimum temperature of the observation point at 1.1 m below the bottom of the pipe increases from-15.2℃to-3.0,1.5,and 7.5℃,corresponding to the heating cable power of 20,30,and 40 W,respectively,with the power of 30 W deemed appropriate for the study case.It is concluded that heating cables in combination with insulation slabs could be adopted to regulate the temperature field around the chilled pipeline efficiently and economically.The advantages of this combination include redirecting the heat flow and eliminating frost in the soil underlying the pipe.These approaches could be considered for applications in gas pipeline projects in arctic and alpine/high-plateau permafrost regions.
基金the National Natural Science Foundation of China(No.21776319 and No.21476269).
文摘In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.
文摘In the present study, an enviro-friendly synthesis of silver nanoparticles from Berberis lycium Royle leaf extract and their antibacterial efficacy against five pathogenic bacteria were investigated. This biosynthesis technique is proved to be advantageous over physical and chemical methods as no toxic chemicals are used. The structural and morphological characterization was made by UV-visible spectroscopy, scanning electron microscopy, and transmission electron microscopy. The synthesized nanoparticles were oval, rectangular, and spherical in shape, size ranges from 8 to 100 nm and exhibited an absorption peak at 458 nm. The biosynthesized silver nanoparticles have shown good antibacterial effect toward tested bacteria. It is believed that these biosynthesized silver nanoparticles can play a vital role in nano-based products in future.
基金Funded by the Youth Fund Project of Yibin University (No. QJ05-28)
文摘We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide (TiO2) coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 (TiO2/cinder). Results show that the decolorization rate of Congo red solution was more than 98% after 2 h treatment when we used TiO2/cinder calcined at 500 °C for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.
文摘Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature phase transformation. Electrochemical measurements showed that the nanohybrid anodes possessed enhanced reversible capacity and superior cycling stability compared to those of a pristine T-Nb205 nanowire electrode. Owing to the strong bonds between graphene nanosheets and T-Nb2O5 nanowires, the nanohybrids achieved an initial capacity of 227 mAh·g^-1. Additionally, non-aqueous asymmetric supercapacitors （ASCs） were fabricated with the synthesized nanohybrids as the anode and activated carbon as the cathode. The 3 V Li-ion ASC with a LiPF6-based organic electrolyte achieved an energy density of 45.1 Wh·kg^-1 at 715.2 W·kg^-1. The working potential could be further enhanced to 4 V when a polymer ionogel separator （PVDF-HFP/LiTFSI/EMIMBF4） and formulated ionic liquid electrolyte were employed. Such a quasi-solid state ASC could operate at 60℃ and delivered a maximum energy density of 70 Wh·kg^-1 at 1 kW·kg^-1.
