The pyrolytic carbon （PyC） coatings were fabricated on A1203 fiber fabrics by the method of chemical vapor deposition （CVD）. The microstructures of A1203 fibers with and without PyC coatings were characterized by ...The pyrolytic carbon （PyC） coatings were fabricated on A1203 fiber fabrics by the method of chemical vapor deposition （CVD）. The microstructures of A1203 fibers with and without PyC coatings were characterized by SEM and Raman spectroscopy. The influence of deposition time of PyC on the DC conductivity （ad） of A1203 filaments and complex permittivity of fabrics at X band （8.2-12.4 GHz） were investigated. The values of Crd and complex permittivity increase with increasing deposition time of PyC. The electron relaxation polarization and conductance loss were supposed to be contributed to the increase of ε＇ and ε＂, respectively. In addition, the reflection loss （RL） of fabrics was calculated. The results show that the microwave absorbing properties of Al2O3 fiber fabrics can be improved by PyC coatings. The best RL results are for 60 min-deposition sample, of which the minimum value is about -40.4 dB at about 9.5 GHz and the absorbing frequency band （AFB） is about 4 GHz.展开更多
It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium...It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium fire”which is easily happened.MTU Aero Engines GmbH has developed a complex functional coating which has great performance of burn resistant and sealing,the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance.In this study,the complex functional coating which is composed of an electro-spark deposited amorphous Ti40Zr25Ni3 burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface.Then the heat insulation ability,burn resistant performance and the bonding strength were investigated.The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded,and the average bonding strength was 36.335 MPa;when the temperature of the flame on the one side of the specimen reached 600℃,the average insulated temperature of the coating samples was 70.67℃;when the flame temperature was 350℃,the titanium samples without the complex functional coatings were burned,while the samples with the coating showed great performance of burn resistant even when the temperature was 750℃.This indicates that the new functional coating has good heat-insulating and burn-resistant performance.展开更多
The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. ...The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.展开更多
This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO proc...This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO process typically generates a porous oxide layer,which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate.To address this limitation,phenopyridine(PHEN)and 2-methylimidazole(2-IMD)were incorporated into the PEO surface to form a robust organic layer on the Mg alloy.Potassium hydroxide(KOH)was used to adjust the pH,improving the interaction and solubility between the organic molecules and the PEO coating.The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity.The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance,with the lowest corrosion current density(I_(corr))of 1.92×10^(-10) A/cm^(2),a high corrosion potential(E_(corr)),and the highest top layer resistance(R_(top))of 2.57×10^(6)Ω·cm^(2),indicating excellent barrier properties.Additionally,the coating achieved complete(100%)degradation of methylene blue(MB)within 30 min under visible light.Density Functional Theory(DFT)calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN,2-IMD,and the PEO layer on the Mg alloy and MB dye.These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.展开更多
Marine fouling is a worldwide challenge with huge damages on industrial structures,side effects on economics of industries,and environmental and safety-related hazards.Different approaches have been used for combating...Marine fouling is a worldwide challenge with huge damages on industrial structures,side effects on economics of industries,and environmental and safety-related hazards.Different approaches have been used for combating fouling in the marine environment.Meanwhile,nanocomposite polymer coatings are a novel generation of antifouling coatings with merits of toxin-free chemical composition and ease of large-scale application.Nanomaterials such as nano-metals,nano-metal oxides,metal-organic frameworks,carbon-based nanostructures,MXene,and nanoclays have antibacterial and antifouling properties in the polymer coatings.Besides,these nanomaterials can improve the corrosion resistance,mechanical strength,weathering stability,and thermal resistance of the polymer coatings.Therefore,in this review paper,the antifouling nanocomposite coatings are introduced and antifouling mechanisms are discussed.This review explicitly indicates that the antifouling efficiency of the nanocomposite coatings depends on the properties of the polymer matrix,the inherent properties of the nanomaterials,the weight percent and the dispersion method of the nanomaterials within the coating matrix,and the chemicals used for modifying the surface of the nanomaterials;meanwhile,the hybrids of different nanomaterials and appropriate chemical agents could be used to improve the antifouling behavior of the prepared nanocomposites.Moreover,the theoretical studies are introduced to pave the way of researchers working on theantifouling coatings,and the importance of the theoretical studies and computational modeling along with the experimental research is notified to develop antifouling coatings with high efficiency.展开更多
The ionic composition of an iminodiacetate electrolyte as a function of solution composition and pH has been deter-mined. The kinetic parameters (exchange currents and apparent transfer coefficients) of the electrored...The ionic composition of an iminodiacetate electrolyte as a function of solution composition and pH has been deter-mined. The kinetic parameters (exchange currents and apparent transfer coefficients) of the electroreduction of a palla-dium(II) bis-iminodiacetate complex from an electrolyte containing excess ligand have been calculated. It has been shown that the rate of the electrode process is controlled by the diffusion of reduced ions to the electrode surface and by the electron-transfer reaction. The possibility of using iminodiacetate electrolyte for palladium plating for the deposition of fine-crystalline adherent and ductile palladium coatings has been examined.展开更多
This paper constructs and studies a nonlinear multivariate regression-tensor model for substantiation of necessary/sufficient conditions of optimization of technological calculation of multifactor physical and chemica...This paper constructs and studies a nonlinear multivariate regression-tensor model for substantiation of necessary/sufficient conditions of optimization of technological calculation of multifactor physical and chemical process of hardening of complex composite media for metal coatings. An adaptive a posteriori procedure for parametric formation of the target quality functional of integrative physical and mechanical properties of the designed metal coating has been proposed. The results of the research may serve as elements of a mathematical language when creating automated design of precision nanotechnologies for surface hardening of complex composite metal coatings on the basis of complex tribological and anticorrosive tests.展开更多
Adsorption and desorption mechanisms of methylene blue (MB) removal with iron-oxide coated porous ce-ramics filter (IOCPCF) were investigated in batch and column mode. The results revealed that MB removal mechanisms i...Adsorption and desorption mechanisms of methylene blue (MB) removal with iron-oxide coated porous ce-ramics filter (IOCPCF) were investigated in batch and column mode. The results revealed that MB removal mechanisms included physical adsorption and chemical adsorption, of which chemical adsorption by surface ligand complex reaction played a dominant role after infrared spectrum analysis. Recycling agents were se-lected from dilute nitric acid (pH=3), sodium hydroxide solution (pH=12) and distilled water. Among three agents, dilute metric acid (pH=3) was the best recycling agent. Regeneration rate of IOCPCF arrived at 82.56% at batch adsorption and regeneration was finished in 75min at column adsorption. Adsorp-tion-desorption cycles of IOCPCF after batch and column adsorption were four and three times, respectively. Further, compared with fresh IOCPCF, MB removal rate with these desorbed IOCPCF adsorption only slightly decreased, which suggested that IOCPCF should be used repeatedly.展开更多
The preparation process of the Cr（III） bath was studied based on a perspective of accelerating the formation of active Cr（III） complexes. The results of ultraviolet-visible absorption spectroscopy （UV-Vis） and e...The preparation process of the Cr（III） bath was studied based on a perspective of accelerating the formation of active Cr（III） complexes. The results of ultraviolet-visible absorption spectroscopy （UV-Vis） and electrodeposition showed that active Cr（III） complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr（III） complexes. The chromium deposition rate increased with the concentration of active Cr（III） complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr（III） complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr（H20）4（OH）L2＋ （L is an organic ligand, and its valence is omitted） is a primary active Cr（III） complex.展开更多
The electromagnetic scattering computation has developed rapidly for many years; some computing problems for complex and coated targets cannot be solved by using the existing theory and computing models. A computing m...The electromagnetic scattering computation has developed rapidly for many years; some computing problems for complex and coated targets cannot be solved by using the existing theory and computing models. A computing model based on data is established for making up the insufficiency of theoretic models. Based on the ＂support vector regression method＂, which is formulated on the principle of minimizing a structural risk, a data model to predicate the unknown radar cross section of some appointed targets is given. Comparison between the actual data and the results of this predicting model based on support vector regression method proved that the support vector regression method is workable and with a comparative precision.展开更多
A three-phase composite cylinder model is utilized to study the interaction of a wedge disclination dipole with a coated cylindrical inhomogeneity. The explicit expression of the force acting on the wedge disclination...A three-phase composite cylinder model is utilized to study the interaction of a wedge disclination dipole with a coated cylindrical inhomogeneity. The explicit expression of the force acting on the wedge disclination dipole is calculated. The motilities and the equilibrium po- sitions of the disclination dipole near the coated inhomogeneity are discussed for various material combinations, relative thicknesses of the coating layer and the features of the disclination dipole. The results show that the material properties of the coating layer have a major part to play in alteringi the strengthening effect or toughening effect produced by the coated inhomogeneity.展开更多
Antibiotic resistance is one of the major issues in the medical field and a potential threat to human health.However,newly emerging antimicrobial compounds failed to combat antimicrobial resistance developed by bacter...Antibiotic resistance is one of the major issues in the medical field and a potential threat to human health.However,newly emerging antimicrobial compounds failed to combat antimicrobial resistance developed by bacterial pathogens.Recently,a bismuth-based complex has been developed to eradicate antimicrobial-resistant microorganism infections.The complex is known as organobismuth(III)phosphinate,which is said to be a potential broad-spectrum antimicrobial agent.This complex has been incorporated into the nanocellulose suspension to fabricate a biomedical composite for various applications.The composite can be fabricated by two methods namely vacuum filtration and spray coating.In this paper,the surface and topography of the composite are investigated and discussed in terms of SEM micrographs and their antimicrobial potential.This review focuses on the organo-bismuth nanocellulose composite and its biomedical application in the future.展开更多
We study the thermoelectric field for an electrically and thermally insulated coated hole of arbitrary shape embedded in an infinite nonlinearly coupled thermoelectric material subject to uniform remote electric curre...We study the thermoelectric field for an electrically and thermally insulated coated hole of arbitrary shape embedded in an infinite nonlinearly coupled thermoelectric material subject to uniform remote electric current density and uniform remote energy flux.A conformal mapping function for the coating and matrix is introduced,which simultaneously maps the hole boundary and the coating-matrix interface onto two concentric circles in the image plane.Using analytic continuation,we derive a general solution in terms of two auxiliary functions.The general solution satisfies the insulating conditions along the hole boundary and all of the continuity conditions across the perfect coating-matrix interface.Once the two auxiliary functions have been obtained in the elementary-form,the four original analytic functions in the coating and matrix characterizing the thermoelectric fields are completely and explicitly determined.The design of a neutral coated circular hole that does not disturb the prescribed thermoelectric field in the thermoelectric matrix is achieved when the relative thickness parameter and the two mismatch parameters satisfy a simple condition.Finally,the neutrality of a coated circular thermoelectric inhomogeneity is also accomplished.展开更多
The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （...The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （DAC） and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10：1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37℃.展开更多
基金Project (51072165) supported by the National Natural Science Foundation of ChinaProject (KP200901) supported by the Fund of the State Key Laboratory of Solidification Processing,China
文摘The pyrolytic carbon （PyC） coatings were fabricated on A1203 fiber fabrics by the method of chemical vapor deposition （CVD）. The microstructures of A1203 fibers with and without PyC coatings were characterized by SEM and Raman spectroscopy. The influence of deposition time of PyC on the DC conductivity （ad） of A1203 filaments and complex permittivity of fabrics at X band （8.2-12.4 GHz） were investigated. The values of Crd and complex permittivity increase with increasing deposition time of PyC. The electron relaxation polarization and conductance loss were supposed to be contributed to the increase of ε＇ and ε＂, respectively. In addition, the reflection loss （RL） of fabrics was calculated. The results show that the microwave absorbing properties of Al2O3 fiber fabrics can be improved by PyC coatings. The best RL results are for 60 min-deposition sample, of which the minimum value is about -40.4 dB at about 9.5 GHz and the absorbing frequency band （AFB） is about 4 GHz.
文摘It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium fire”which is easily happened.MTU Aero Engines GmbH has developed a complex functional coating which has great performance of burn resistant and sealing,the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance.In this study,the complex functional coating which is composed of an electro-spark deposited amorphous Ti40Zr25Ni3 burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface.Then the heat insulation ability,burn resistant performance and the bonding strength were investigated.The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded,and the average bonding strength was 36.335 MPa;when the temperature of the flame on the one side of the specimen reached 600℃,the average insulated temperature of the coating samples was 70.67℃;when the flame temperature was 350℃,the titanium samples without the complex functional coatings were burned,while the samples with the coating showed great performance of burn resistant even when the temperature was 750℃.This indicates that the new functional coating has good heat-insulating and burn-resistant performance.
文摘The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘This study explores the development of an organic-inorganic hybrid coating to enhance the corrosion resistance and photocatalytic properties of AZ31 Mg alloy modified by plasma electrolytic oxidation(PEO).The PEO process typically generates a porous oxide layer,which can reduce corrosion protection by allowing corrosive agents to penetrate the substrate.To address this limitation,phenopyridine(PHEN)and 2-methylimidazole(2-IMD)were incorporated into the PEO surface to form a robust organic layer on the Mg alloy.Potassium hydroxide(KOH)was used to adjust the pH,improving the interaction and solubility between the organic molecules and the PEO coating.The hybrid coating exhibited unique twig-like surface structures that contributed to forming a multifunctional coating with high corrosion resistance and superior photocatalytic activity.The PEO-PHEN-2IMD sample on the Mg alloy demonstrated exceptional corrosion resistance,with the lowest corrosion current density(I_(corr))of 1.92×10^(-10) A/cm^(2),a high corrosion potential(E_(corr)),and the highest top layer resistance(R_(top))of 2.57×10^(6)Ω·cm^(2),indicating excellent barrier properties.Additionally,the coating achieved complete(100%)degradation of methylene blue(MB)within 30 min under visible light.Density Functional Theory(DFT)calculations provide deeper insights into the bonding mechanisms and interaction stability between PHEN,2-IMD,and the PEO layer on the Mg alloy and MB dye.These findings confirmed the enhanced performance of the hybrid coating in both corrosion resistance and photocatalytic applications.
基金supported financially by the CAS President’s International Fellowship Initiative 2019(PIFI,No.2019PE0059)CAS-VPST Silk Road Science Fund 2021(133137KYSB20200034)INSF’s Project No.99010368。
文摘Marine fouling is a worldwide challenge with huge damages on industrial structures,side effects on economics of industries,and environmental and safety-related hazards.Different approaches have been used for combating fouling in the marine environment.Meanwhile,nanocomposite polymer coatings are a novel generation of antifouling coatings with merits of toxin-free chemical composition and ease of large-scale application.Nanomaterials such as nano-metals,nano-metal oxides,metal-organic frameworks,carbon-based nanostructures,MXene,and nanoclays have antibacterial and antifouling properties in the polymer coatings.Besides,these nanomaterials can improve the corrosion resistance,mechanical strength,weathering stability,and thermal resistance of the polymer coatings.Therefore,in this review paper,the antifouling nanocomposite coatings are introduced and antifouling mechanisms are discussed.This review explicitly indicates that the antifouling efficiency of the nanocomposite coatings depends on the properties of the polymer matrix,the inherent properties of the nanomaterials,the weight percent and the dispersion method of the nanomaterials within the coating matrix,and the chemicals used for modifying the surface of the nanomaterials;meanwhile,the hybrids of different nanomaterials and appropriate chemical agents could be used to improve the antifouling behavior of the prepared nanocomposites.Moreover,the theoretical studies are introduced to pave the way of researchers working on theantifouling coatings,and the importance of the theoretical studies and computational modeling along with the experimental research is notified to develop antifouling coatings with high efficiency.
文摘The ionic composition of an iminodiacetate electrolyte as a function of solution composition and pH has been deter-mined. The kinetic parameters (exchange currents and apparent transfer coefficients) of the electroreduction of a palla-dium(II) bis-iminodiacetate complex from an electrolyte containing excess ligand have been calculated. It has been shown that the rate of the electrode process is controlled by the diffusion of reduced ions to the electrode surface and by the electron-transfer reaction. The possibility of using iminodiacetate electrolyte for palladium plating for the deposition of fine-crystalline adherent and ductile palladium coatings has been examined.
文摘This paper constructs and studies a nonlinear multivariate regression-tensor model for substantiation of necessary/sufficient conditions of optimization of technological calculation of multifactor physical and chemical process of hardening of complex composite media for metal coatings. An adaptive a posteriori procedure for parametric formation of the target quality functional of integrative physical and mechanical properties of the designed metal coating has been proposed. The results of the research may serve as elements of a mathematical language when creating automated design of precision nanotechnologies for surface hardening of complex composite metal coatings on the basis of complex tribological and anticorrosive tests.
文摘Adsorption and desorption mechanisms of methylene blue (MB) removal with iron-oxide coated porous ce-ramics filter (IOCPCF) were investigated in batch and column mode. The results revealed that MB removal mechanisms included physical adsorption and chemical adsorption, of which chemical adsorption by surface ligand complex reaction played a dominant role after infrared spectrum analysis. Recycling agents were se-lected from dilute nitric acid (pH=3), sodium hydroxide solution (pH=12) and distilled water. Among three agents, dilute metric acid (pH=3) was the best recycling agent. Regeneration rate of IOCPCF arrived at 82.56% at batch adsorption and regeneration was finished in 75min at column adsorption. Adsorp-tion-desorption cycles of IOCPCF after batch and column adsorption were four and three times, respectively. Further, compared with fresh IOCPCF, MB removal rate with these desorbed IOCPCF adsorption only slightly decreased, which suggested that IOCPCF should be used repeatedly.
基金financially supported by the National Basic Research and Development Program of China(No.2013CB632606)the National Natural Science Foundation of China(No.51274180)
文摘The preparation process of the Cr（III） bath was studied based on a perspective of accelerating the formation of active Cr（III） complexes. The results of ultraviolet-visible absorption spectroscopy （UV-Vis） and electrodeposition showed that active Cr（III） complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr（III） complexes. The chromium deposition rate increased with the concentration of active Cr（III） complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr（III） complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr（H20）4（OH）L2＋ （L is an organic ligand, and its valence is omitted） is a primary active Cr（III） complex.
文摘The electromagnetic scattering computation has developed rapidly for many years; some computing problems for complex and coated targets cannot be solved by using the existing theory and computing models. A computing model based on data is established for making up the insufficiency of theoretic models. Based on the ＂support vector regression method＂, which is formulated on the principle of minimizing a structural risk, a data model to predicate the unknown radar cross section of some appointed targets is given. Comparison between the actual data and the results of this predicting model based on support vector regression method proved that the support vector regression method is workable and with a comparative precision.
基金Project supported by the National Natural Science Foundation of China(Nos.11172094 and 11172095)the New Century Excellent Talents in University(NCET-11-0122)Hunan Provincial Natural Science Foundation for Creative Research Groups of China(No.12JJ7001)
文摘A three-phase composite cylinder model is utilized to study the interaction of a wedge disclination dipole with a coated cylindrical inhomogeneity. The explicit expression of the force acting on the wedge disclination dipole is calculated. The motilities and the equilibrium po- sitions of the disclination dipole near the coated inhomogeneity are discussed for various material combinations, relative thicknesses of the coating layer and the features of the disclination dipole. The results show that the material properties of the coating layer have a major part to play in alteringi the strengthening effect or toughening effect produced by the coated inhomogeneity.
文摘Antibiotic resistance is one of the major issues in the medical field and a potential threat to human health.However,newly emerging antimicrobial compounds failed to combat antimicrobial resistance developed by bacterial pathogens.Recently,a bismuth-based complex has been developed to eradicate antimicrobial-resistant microorganism infections.The complex is known as organobismuth(III)phosphinate,which is said to be a potential broad-spectrum antimicrobial agent.This complex has been incorporated into the nanocellulose suspension to fabricate a biomedical composite for various applications.The composite can be fabricated by two methods namely vacuum filtration and spray coating.In this paper,the surface and topography of the composite are investigated and discussed in terms of SEM micrographs and their antimicrobial potential.This review focuses on the organo-bismuth nanocellulose composite and its biomedical application in the future.
基金supported by the Discovery Grant from the Natural Sciences and Engineering Research Council of Canada(No.RGPIN-2017-03716115112)。
文摘We study the thermoelectric field for an electrically and thermally insulated coated hole of arbitrary shape embedded in an infinite nonlinearly coupled thermoelectric material subject to uniform remote electric current density and uniform remote energy flux.A conformal mapping function for the coating and matrix is introduced,which simultaneously maps the hole boundary and the coating-matrix interface onto two concentric circles in the image plane.Using analytic continuation,we derive a general solution in terms of two auxiliary functions.The general solution satisfies the insulating conditions along the hole boundary and all of the continuity conditions across the perfect coating-matrix interface.Once the two auxiliary functions have been obtained in the elementary-form,the four original analytic functions in the coating and matrix characterizing the thermoelectric fields are completely and explicitly determined.The design of a neutral coated circular hole that does not disturb the prescribed thermoelectric field in the thermoelectric matrix is achieved when the relative thickness parameter and the two mismatch parameters satisfy a simple condition.Finally,the neutrality of a coated circular thermoelectric inhomogeneity is also accomplished.
基金SUPPORTED BY NATURAL SCIENCE FOUNDATION OF TIANJIN ( NO. 033802011).
文摘The urea nitrogen adsorbent of complex type, which consists of chitosan coated dialdehyde cellulose （CDAC） and immobilized urease in gelatin membrane （IE）, was prepared. The cellulose, the dialdehyde cellulose （DAC） and the CDAC were characterized by scanning electronic microscope. The results indicate that the cellulose C2-C3 bond was broken under the oxidation of periodate and it was oxidated to DAC. The DAC was coated with chitosan and the CDAC was obtained. The adsorption of urea nitrogen onto the adsorbent in Na2HPO4-NaH2PO4 buffer solution was studied in batch system. The effects of the experiment parameters, including degree of oxidation of CDAC, initial urea nitrogen concentration, pH and temperature, on the adsorption capacity of urea nitrogen onto the adsorbent at CDAC/IE weight ratio 10：1 were investigated. The results indicate that these parameters affected significantly the adsorption capacity. The adsorption capacity of urea nitrogen onto the adsorbent was 36.7 mg/g at the degree of oxidation of CDAC 88%, initial urea nitrogen concentration 600 mg/L, pH 7.4 and temperature 37℃.
