We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. B...We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.展开更多
Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron ...Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.展开更多
The present article provides an overview of the chemical and physical features of haze in China, focusing on the relationship between haze and atmospheric fine particles, and the formation mechanism of haze. It also s...The present article provides an overview of the chemical and physical features of haze in China, focusing on the relationship between haze and atmospheric fine particles, and the formation mechanism of haze. It also summarizes several of control technologies and strategies to mitigate the occurrence of haze. The development of instruments and the analysis of measurements of ambient particles and precursor concentrations have provided important information about haze formation. Indeed, the use of new instruments has greatly facilitated current haze research in China. Examples of insightful results include the relationship between fine particles and haze, the chemical compositions and sources of particles, the impacts of the aging process on haze formation, and the application of technologies that control the formation of haze. Based on these results, two relevant issues need to be addressed： understanding the relationship between haze and fine particles and understanding how to control PM2.5.展开更多
Nano-calcium carbonate composite particles were synthesized by the soapless emulsion polymerization technique of double monomers. The composite particles formation mechanism was investigated. The effects of composite ...Nano-calcium carbonate composite particles were synthesized by the soapless emulsion polymerization technique of double monomers. The composite particles formation mechanism was investigated. The effects of composite particles on the mechanical properties of nano-CaCO3-ABS （acrylonitrile-butadiene-styrene copolymer） composite material were studied. It was validated that the composite particles are made up of the nano-calcium carbonate cores and the shells of alternating copolymers of butyl acrylate （BA） and styrene （St）. The shells are chemically grafted and physically wrapped on the surface of nano-calcium carbonate particles. When the composite particles were filled in ABS matrix, the CaCO3 particles are homogeneously dispersed in the composite material as nanoscales. The impact strength of the composite material is obviously enhanced after filling appropriate amounts of composite particles. It can be concluded that the soapless emulsion polymerization of double monomers is an effective method for nano-CaCO3 surface treatment. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
Polystyrene coated silica（SiO_2@PS） core-shell composite particles with averaged diameter of about 290 nm were prepared by in situ emulsion polymerization of styrene on the surface ofγ-methacryloxypropyltrimethoxys...Polystyrene coated silica（SiO_2@PS） core-shell composite particles with averaged diameter of about 290 nm were prepared by in situ emulsion polymerization of styrene on the surface ofγ-methacryloxypropyltrimethoxysilane grafted SiO_2 nanoparticles of 20-50 nm in diameter.Rheological behavior and dispersion stability of SiO_2@PS suspension in 10 wt%PS solution were compared with suspensions of untreated SiO_2 and silane modified SiO_2 nanoparticles.Suspensions of the untreated and the silane modified SiO_2 exhibited obvious shear thinning.The SiO-2@PS suspension exhibits shear viscosity considerably smaller than suspensions of untreated and silane modified SiO_2 at low shear rates.Transmission electron microscopy showed that the composite particles can uniformly and stably disperse in PS solution compared to other suspensions,implying that the PS shell can effectively enhance the particle compatibility with PS macromolecules in solution.展开更多
（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforc...（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.展开更多
Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic...Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.展开更多
Diamond particles reinforced aluminum–silicon matrix composites,abbreviated as Al（Si）/diamond composites,were fabricated by squeeze casting.The effect of Si content on the microstructure and mechanical properties o...Diamond particles reinforced aluminum–silicon matrix composites,abbreviated as Al（Si）/diamond composites,were fabricated by squeeze casting.The effect of Si content on the microstructure and mechanical properties of the composites were investigated.The mechanical properties are found to increase monotonically with Si content increasing up to 7.0 wt%.The Al-7.0 wt% Si/diamond composite exhibits tensile strength of 78 MPa,bending strength of 230 MPa,and compressive strength of426 MPa.Al–Si eutectic phases are shown to connect with Al matrix and diamond particles tightly,which is responsible for the enhancement of mechanical properties in the Al（Si）/diamond composites.展开更多
In this paper, a facile synthesis of 100 nm commercial colloid silica coated with nano-ceria core-shell composite particles by the precipitation method using ammonium cerium nitrate and urea as a precipitator with pol...In this paper, a facile synthesis of 100 nm commercial colloid silica coated with nano-ceria core-shell composite particles by the precipitation method using ammonium cerium nitrate and urea as a precipitator with polyvinylpyrrolidone （PVP） as an assistant was briefly introduced. The results showed that the colloid silica was surrounded by nano-ceria uniformly forming the core-shell composite particles. The synthesis process was further discussed and optimized. It was found that the type and quantity of surfactant played a key role in the process. PVP connected the surface of colloid silica and that of the ceria precursor.展开更多
Polyaniline-barium titanate (PAn-Ba-TiO3) ultrafine composite particles were prepared by the oxidative polymerization of aniline with H2O2 while barium titanate nanoparticles were synthesized with a sol-gel method. Th...Polyaniline-barium titanate (PAn-Ba-TiO3) ultrafine composite particles were prepared by the oxidative polymerization of aniline with H2O2 while barium titanate nanoparticles were synthesized with a sol-gel method. The infrared spectrogram shows that the polymerization of PAn in the hybrid process of PAn-BaTiO3 is similar with the polymeric process of pure aniline, and there is interaction of PAn and BaTiO3 in the PAn-Ba-TiO3. SEM and TEM results show that the average diameter of the composite particles is 1.50μm and the diameters of BaTiO3 nanoparticles are 5 - 15 nm in the composite particle. The electrical conductivity of the ultrafine com-posite particles is transformable from 10°to 10-11S/cm by equilibrium doping or dedoping method using various concentration of HCl or NaOH solutions.展开更多
A model with three-layer structure is introduced to explore the acoustic radiation force(ARF)on composite particles with an elastic thin shell.Combing acoustic scattering of cylinder and the thin-shell theorem,the ARF...A model with three-layer structure is introduced to explore the acoustic radiation force(ARF)on composite particles with an elastic thin shell.Combing acoustic scattering of cylinder and the thin-shell theorem,the ARF expression was derived,and the longitudinal and transverse components of the force and axial torque for an eccentric liquid-filled composite particle was obtained.It was found that many factors,such as medium properties,acoustic parameters,eccentricity,and radius ratio of the inner liquid column,affect the acoustic scattering field of the particle,which in turn changes the forces and torque.The acoustic response varies with the particle structures,so the resonance peaks of the force function and torque shift with the eccentricity and radii ratio of particle.The acoustic response of the particle is enhanced and exhibits higher force values due to the presence of the elastic thin shell and the coupling effect with the eccentricity of the internal liquid column.The decrease of the inner liquid density may suppress the high-order resonance peaks,and internal fluid column has less effects on the change in force on composite particle at ka>3,while limited differences exist at ka<3.The axial torque on particles due to geometric asymmetry is closely related to ka and the eccentricity.The distribution of positive and negative force and torque along the axis ka exhibits that composite particle can be manipulated or separated by ultrasound.Our theoretical analysis can provide support for the acoustic manipulation,sorting,and targeting of inhomogeneous particles.展开更多
Al_(2)O_(3) particles reinforced hypereutectic Al-Si composites were prepared by in situ Fe_(2)O_(3)/Al reaction system.The thermodynamic analysis and microstructure evolution were investigated by differential scannin...Al_(2)O_(3) particles reinforced hypereutectic Al-Si composites were prepared by in situ Fe_(2)O_(3)/Al reaction system.The thermodynamic analysis and microstructure evolution were investigated by differential scanning calorimetry,optical microscope,scanning electronic microscopy and transmission electron microscope.Results show that the reaction between Fe_(2)O_(3) and Al is spontaneous which can be separated into two steps at different temperatures.The in situ Al_(2)O_(3) particles in nano size distribute on the Al matrix accompanied with long needle-shapedβFe-rich intermetallic phase.With different content of Mn addition,βphase can be modified toα-Al15(Mn,Fe)3Si2 andδ-Al4(Fe,Mn)Si2.Both tensile strength and elongation results at room temperature and 300℃reveal that the optimal Fe-rich intermetallic phase is finer Chinese-script and polyhedralαphase with a Mn/Fe mass ratio 0.5 for the composites.Both in situ Al_(2)O_(3) particles andα-Fe phases contribute to the properties improvement of the composites。展开更多
By using SrTiO 3/PANI as a dispersed phase and silicone oil as a dispersion medium, the rheological characteristic of the dispersion medium under an electric field and the ERF performances of the mixture of SrTiO 3/...By using SrTiO 3/PANI as a dispersed phase and silicone oil as a dispersion medium, the rheological characteristic of the dispersion medium under an electric field and the ERF performances of the mixture of SrTiO 3/PANI composite particles and silicone oil under different dispersed phase consistencies and different medium viscosities have been investigated. The measurements of the rheological characteristic, that is the shear stress of ERF, under shearing flow were performed with a Couette-type rheometer manufactured by HAAKE. It is proved that the rheological characteristic of the dispersion medium follows Newtonian fluid viscosity law and the ERF rheological characteristic of the mixture of the dispersion medium and dispersed phase obeys Bingham fluid model under electric field. The experimental result shows that the effects of different phase consistencies and different dispersion medium viscosities on ERF performances are great. The testing expressions of shear stress vs. electric field under different conditions have been obtained by polynomial fit, which is the theory foundation of application in engineering.展开更多
Multiresponsive magnetic microgels were synthesized using Fe3O4 nanomagnetic particles as seeds by precipitation polymerization. Thermogravimetric analysis (TGA) shows that the magnetic particles can be adequately enc...Multiresponsive magnetic microgels were synthesized using Fe3O4 nanomagnetic particles as seeds by precipitation polymerization. Thermogravimetric analysis (TGA) shows that the magnetic particles can be adequately encapsulated by resultant copolymer in reaction, and the amount of coating copolymer is about 78.9%. Magnetic measurement reveals that the composite particles have strong magnetic sensitivity and superparamagnetic property. The drug release as a function of temperature and pH shows that the release percentage at high temperature is significantly lower than low temperature, indicating a slow release behavior, and the release at various pH conditions does not carry out a prominent difference. This concerns the responsive degree of coating polymer on magnetic particles to pH solution.展开更多
In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As...In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel particles were obtained. The morphology and composition of the particles were analyzed with scanning electron microscopy(SEM), energy scattering x-ray spectroscopy(EDS), Fourier infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The analysis results confirmed that the particles were the expected ones. TiO2 was dispersed homogeneously within the spheroidal particles. Compared to the control gel, the composite gel particles not only contained Ti element but also showed higher thermal stability. In addition, the photo-catalytic behavior of the particles for the degradation of methyl orange contained in aqueous solution was examined. The particles exhibited photocatalytic characteristic for the degradation of the model dye, which could be modulated by simply varying the amount of cross-linking agent or TiO2. The photo-catalytic degradation percentage of methyl orange maintained at 91%-96% after using the particles three times, which indicated that TiO2 could played its role repeatedly via being fixated within polyvinyl alcohol-based gel.展开更多
Ensembles of freeze-dried self-rolled polymer micro-scrolls are explored as template media for produc- ing carbon-iron based composites with fibrous morphology. Polymer fibres impregnated with furfuryl alcohol and loa...Ensembles of freeze-dried self-rolled polymer micro-scrolls are explored as template media for produc- ing carbon-iron based composites with fibrous morphology. Polymer fibres impregnated with furfuryl alcohol and loaded with Fe2O3 particles, were thermally treated under inert atmosphere at 700 ℃ and subsequently analysed by scanning and transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and nitrogen adsorption. The resulting material has a micro-fibrous mor- phology and is basically composed of metallic Fe^0 and FeO particles, i.e., more than 98 wt% of the carbon/ iron-based composite mass. These particles are held together by amorphous porous carbon foam obtained by in-situ carbonization of the polymer/Fe2O3 composite with evacuation of carbon from the system via COx gases released by carbo-reduction of Fe2O3. The material has significant activity in the reaction of catalytic decomposition of hydrogen peroxide in water solutions.展开更多
This study aimed to compare and analyze the effects of different modifiers on the structure,free surface energy parameters,and direct compaction properties of composite particles(CPs)prepared by co-spray drying and to...This study aimed to compare and analyze the effects of different modifiers on the structure,free surface energy parameters,and direct compaction properties of composite particles(CPs)prepared by co-spray drying and to explore the correlation among structure,free surface energy parameters,and direct compaction properties of CPs.CPs with Puerariae lobatae radix were prepared by adding different modifiers.The structure,free surface energy parameters,and direct compaction properties of cPs were characterized.Furthermore,Pearson correlation analysis and artificial neural network methods were used to evaluate the correlation among structure,free surface energy parameters,and direct compaction properties of CPs.The results showed that different modifiers exhibited variegated effects on the structure,free surface energy parameters,and direct compaction properties of cPs.Pearson correlation analysis showed that the particle size distribution,uniformity,and brightness were positively correlated with polar components and polarity index,with statistical significance(P<0.01).The polar components and polarity index were positively correlated with flowability and disintegration time,and negatively correlated with compactibility,with statistical significance(P<0.o1).Overall,these findings contribute to better establishing a theoretical model among structure,free surface energy parameters,and direct compaction properties of Ps and provide a theoretical basis for predicting material properties.展开更多
Room-temperature phosphorescence(RTP)materials play a vital role in security domain due to their unique optical properties.However,most average lifetimes of available RTP materials remain less than 1 s in aqueous-phas...Room-temperature phosphorescence(RTP)materials play a vital role in security domain due to their unique optical properties.However,most average lifetimes of available RTP materials remain less than 1 s in aqueous-phase media,which is unfavorable to practical applications.Herein,an ex-situ covalent coupling strategy is proposed to fabricate liquid-phase long-lived RTP materials by combining SiO_(2)microspheres with the feather-derived carbon dots(CDs).Astonishingly,the aqueous dispersion of the resulting CDs@SiO_(2)microspheres exhibits a lifetime of up to 2.38 s with an absolute quantum yield of 22%.Moreover,the average lifetime of the solid CDs@SiO_(2)is as long as 3.04 s,which is superior to that of existing RTP carbon-based materials.The striking enhancements in the RTP of the CDs@SiO_(2)composites are mainly attributed to the immobilization of the formed Si–O–C covalent bonds and Si–O–Si rigid networks.The CDs@SiO_(2)composites were subsequently applied in the fields of information encryption and anti-fake.Interestingly,the CDs@SiO_(2)composites possess intriguing,reversible and stable optical properties,including water-responsive structural colors,blue fluorescence and cyan RTP,exhibiting excellent covert performance in applications of information encryption and decryption,and high-level anticounterfeiting.These findings provide not only a straightforward strategy for developing multiresponsive optical materials but also a more secure anticounterfeiting technology.展开更多
TiO2@ZrO2@Y2O3 ：Eu3＋ composite particles with a core-multishell structure were synthesized through the combination of a layer-by-layer （LBL） self-assembly method and a sol-gel process. The obtained sam- ples were ...TiO2@ZrO2@Y2O3 ：Eu3＋ composite particles with a core-multishell structure were synthesized through the combination of a layer-by-layer （LBL） self-assembly method and a sol-gel process. The obtained sam- ples were characterized with scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and fluorescence spectropho- tometry. The results showed that the composite particles had a core-multishell structure, spherical morphology, and a narrow size distribution. The presence of a ZrO2 layer on the TiO2 core can effec- tively prevent the reaction between the TiO2 core and a Y203 shell; the temperature for the reaction between the TiO2 core and the Y203 shell in the TiO2@ZrO2@Y2O3 ：Eu core-multishell phosphor can be elevated by 300 ℃ compared to that for TiO2@ZrO2：Eu. Upon excitation of the core-multishell particles in the ultraviolet （254 nm）, the Eu3＋ ion in the Y2O3 ：Eu3＋ shell shows its characteristic red emission （611 nm, 5D0→7F2）, and the photoluminescence （PL） intensity of the phosphor with the core-multishell structure was obviously greater than that of the core-shell TiO2@Y2O3 ：Eu phosphor.展开更多
文摘We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.
基金Funded by the National Key Technology R&D Program of China(No.2008BAE60B06)Beijing Municipal Science&Technology Commission (No.Z080003032208015)
文摘Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.
基金supported by the National Nature Science Foundation of China(No.D010504)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB05000000)
文摘The present article provides an overview of the chemical and physical features of haze in China, focusing on the relationship between haze and atmospheric fine particles, and the formation mechanism of haze. It also summarizes several of control technologies and strategies to mitigate the occurrence of haze. The development of instruments and the analysis of measurements of ambient particles and precursor concentrations have provided important information about haze formation. Indeed, the use of new instruments has greatly facilitated current haze research in China. Examples of insightful results include the relationship between fine particles and haze, the chemical compositions and sources of particles, the impacts of the aging process on haze formation, and the application of technologies that control the formation of haze. Based on these results, two relevant issues need to be addressed： understanding the relationship between haze and fine particles and understanding how to control PM2.5.
基金the National Natural Science Foundation of China(No.20236020,20325621)the National R & D Program of China(No.2001BA310A01).
文摘Nano-calcium carbonate composite particles were synthesized by the soapless emulsion polymerization technique of double monomers. The composite particles formation mechanism was investigated. The effects of composite particles on the mechanical properties of nano-CaCO3-ABS （acrylonitrile-butadiene-styrene copolymer） composite material were studied. It was validated that the composite particles are made up of the nano-calcium carbonate cores and the shells of alternating copolymers of butyl acrylate （BA） and styrene （St）. The shells are chemically grafted and physically wrapped on the surface of nano-calcium carbonate particles. When the composite particles were filled in ABS matrix, the CaCO3 particles are homogeneously dispersed in the composite material as nanoscales. The impact strength of the composite material is obviously enhanced after filling appropriate amounts of composite particles. It can be concluded that the soapless emulsion polymerization of double monomers is an effective method for nano-CaCO3 surface treatment. 2008 University of Science and Technology Beijing. All rights reserved.
基金supported by the National Natural Science Foundation of China(No.51073136)the Fundamental Research Funds for the Central Universities of China(No.2010QNA4011)
文摘Polystyrene coated silica（SiO_2@PS） core-shell composite particles with averaged diameter of about 290 nm were prepared by in situ emulsion polymerization of styrene on the surface ofγ-methacryloxypropyltrimethoxysilane grafted SiO_2 nanoparticles of 20-50 nm in diameter.Rheological behavior and dispersion stability of SiO_2@PS suspension in 10 wt%PS solution were compared with suspensions of untreated SiO_2 and silane modified SiO_2 nanoparticles.Suspensions of the untreated and the silane modified SiO_2 exhibited obvious shear thinning.The SiO-2@PS suspension exhibits shear viscosity considerably smaller than suspensions of untreated and silane modified SiO_2 at low shear rates.Transmission electron microscopy showed that the composite particles can uniformly and stably disperse in PS solution compared to other suspensions,implying that the PS shell can effectively enhance the particle compatibility with PS macromolecules in solution.
基金co-supported by the National Natural Science Foundation of China (Nos. 51235004, 51375235)the Fundamental Research Funds for the Central Universities (No. NE2014103) of ChinaPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) of China
文摘（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.
基金Supported by the National High Technology Research and Development Program of China (2006AA020705)
文摘Objective： To establish a method of genomic DNA extraction from whole blood using Fe3O4/Au composite particles as a carrier. Methods： Two crucial conditions （sodium chloride concentration and amount of the magnetic particles） were optimized and 8 different human whole blood samples were used to purify genomic DNA under the optimal condition. Then agarose gel electrophoresis and polymerase cbain reaction （PCR） were performed. Results： The optimal binding condition was 1.5 mol/L NaC1/10% PEG, and the optimal amount of Fe3O4/Au composite particles was 600μg. The yields of the genomic DNA from 100μl of different whole blood samples were 2-5 μg, and the ratio of A260/A280 was in the range of 1.70-1.90. The size of genomic DNA was about 23 kb and the PCR was valid. Conclusion： The purification system using Fe3O4/Au composite microparticles has advantages in high yield, high purity, ease of operating, time saving and avoiding centrifugation. The purified sample was found to function satisfactorily in PCR amplification.
基金financially supported by the National Natural Science Foundation of China (No.51271017)the Fundamental Research Funds for the Central Universities (No.FRFTP-13-033A)the Program for New Century Excellent Talents in University (No.NCET-10-0227)
文摘Diamond particles reinforced aluminum–silicon matrix composites,abbreviated as Al（Si）/diamond composites,were fabricated by squeeze casting.The effect of Si content on the microstructure and mechanical properties of the composites were investigated.The mechanical properties are found to increase monotonically with Si content increasing up to 7.0 wt%.The Al-7.0 wt% Si/diamond composite exhibits tensile strength of 78 MPa,bending strength of 230 MPa,and compressive strength of426 MPa.Al–Si eutectic phases are shown to connect with Al matrix and diamond particles tightly,which is responsible for the enhancement of mechanical properties in the Al（Si）/diamond composites.
基金supported by National Integrate Circuit Research Program of China (Nos.2011ZX02704-002,2009ZX02030-001)National Natural Science Foundation of China (No.51205387)Science and Technology Council of Shanghai (Nos.11nm0500300,10QB1403600)
文摘In this paper, a facile synthesis of 100 nm commercial colloid silica coated with nano-ceria core-shell composite particles by the precipitation method using ammonium cerium nitrate and urea as a precipitator with polyvinylpyrrolidone （PVP） as an assistant was briefly introduced. The results showed that the colloid silica was surrounded by nano-ceria uniformly forming the core-shell composite particles. The synthesis process was further discussed and optimized. It was found that the type and quantity of surfactant played a key role in the process. PVP connected the surface of colloid silica and that of the ceria precursor.
基金Funded by Chinese National Natural Science Foundation (No.29674021) and Key Foundation (No. 59832090). and Open Foundation from State Key Lab. of Advanced Technology for Materials Synthesis and Processing.
文摘Polyaniline-barium titanate (PAn-Ba-TiO3) ultrafine composite particles were prepared by the oxidative polymerization of aniline with H2O2 while barium titanate nanoparticles were synthesized with a sol-gel method. The infrared spectrogram shows that the polymerization of PAn in the hybrid process of PAn-BaTiO3 is similar with the polymeric process of pure aniline, and there is interaction of PAn and BaTiO3 in the PAn-Ba-TiO3. SEM and TEM results show that the average diameter of the composite particles is 1.50μm and the diameters of BaTiO3 nanoparticles are 5 - 15 nm in the composite particle. The electrical conductivity of the ultrafine com-posite particles is transformable from 10°to 10-11S/cm by equilibrium doping or dedoping method using various concentration of HCl or NaOH solutions.
基金the National Natural Science Foundation of China(Grant Nos.12374441 and 11974232)the Fund from Yulin Science and Technology Bureau(Grant No.CXY-2022-178).
文摘A model with three-layer structure is introduced to explore the acoustic radiation force(ARF)on composite particles with an elastic thin shell.Combing acoustic scattering of cylinder and the thin-shell theorem,the ARF expression was derived,and the longitudinal and transverse components of the force and axial torque for an eccentric liquid-filled composite particle was obtained.It was found that many factors,such as medium properties,acoustic parameters,eccentricity,and radius ratio of the inner liquid column,affect the acoustic scattering field of the particle,which in turn changes the forces and torque.The acoustic response varies with the particle structures,so the resonance peaks of the force function and torque shift with the eccentricity and radii ratio of particle.The acoustic response of the particle is enhanced and exhibits higher force values due to the presence of the elastic thin shell and the coupling effect with the eccentricity of the internal liquid column.The decrease of the inner liquid density may suppress the high-order resonance peaks,and internal fluid column has less effects on the change in force on composite particle at ka>3,while limited differences exist at ka<3.The axial torque on particles due to geometric asymmetry is closely related to ka and the eccentricity.The distribution of positive and negative force and torque along the axis ka exhibits that composite particle can be manipulated or separated by ultrasound.Our theoretical analysis can provide support for the acoustic manipulation,sorting,and targeting of inhomogeneous particles.
基金Funded by the National Natural Science Foundation of China(No.51201071)the National Natural Science Foundation of Jiangsu Province(No.BK20161270)Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents(2018)。
文摘Al_(2)O_(3) particles reinforced hypereutectic Al-Si composites were prepared by in situ Fe_(2)O_(3)/Al reaction system.The thermodynamic analysis and microstructure evolution were investigated by differential scanning calorimetry,optical microscope,scanning electronic microscopy and transmission electron microscope.Results show that the reaction between Fe_(2)O_(3) and Al is spontaneous which can be separated into two steps at different temperatures.The in situ Al_(2)O_(3) particles in nano size distribute on the Al matrix accompanied with long needle-shapedβFe-rich intermetallic phase.With different content of Mn addition,βphase can be modified toα-Al15(Mn,Fe)3Si2 andδ-Al4(Fe,Mn)Si2.Both tensile strength and elongation results at room temperature and 300℃reveal that the optimal Fe-rich intermetallic phase is finer Chinese-script and polyhedralαphase with a Mn/Fe mass ratio 0.5 for the composites.Both in situ Al_(2)O_(3) particles andα-Fe phases contribute to the properties improvement of the composites。
文摘By using SrTiO 3/PANI as a dispersed phase and silicone oil as a dispersion medium, the rheological characteristic of the dispersion medium under an electric field and the ERF performances of the mixture of SrTiO 3/PANI composite particles and silicone oil under different dispersed phase consistencies and different medium viscosities have been investigated. The measurements of the rheological characteristic, that is the shear stress of ERF, under shearing flow were performed with a Couette-type rheometer manufactured by HAAKE. It is proved that the rheological characteristic of the dispersion medium follows Newtonian fluid viscosity law and the ERF rheological characteristic of the mixture of the dispersion medium and dispersed phase obeys Bingham fluid model under electric field. The experimental result shows that the effects of different phase consistencies and different dispersion medium viscosities on ERF performances are great. The testing expressions of shear stress vs. electric field under different conditions have been obtained by polynomial fit, which is the theory foundation of application in engineering.
基金Development Funds of Shanghai Science and Technology, China (No. KJ2008-09)
文摘Multiresponsive magnetic microgels were synthesized using Fe3O4 nanomagnetic particles as seeds by precipitation polymerization. Thermogravimetric analysis (TGA) shows that the magnetic particles can be adequately encapsulated by resultant copolymer in reaction, and the amount of coating copolymer is about 78.9%. Magnetic measurement reveals that the composite particles have strong magnetic sensitivity and superparamagnetic property. The drug release as a function of temperature and pH shows that the release percentage at high temperature is significantly lower than low temperature, indicating a slow release behavior, and the release at various pH conditions does not carry out a prominent difference. This concerns the responsive degree of coating polymer on magnetic particles to pH solution.
基金Funded by the Science&Technology Program of Fujian Province(No.2017H0018)
文摘In the presence of titanium dioxide powder, cross-linking reaction between commercial polyvinyl alcohol(PVA)-based macromonomer and acrylic acid(AA) was initiated with potassium persulfate in an emulsifying system. As a result, PVA-AA/TiO2 composite gel particles were obtained. The morphology and composition of the particles were analyzed with scanning electron microscopy(SEM), energy scattering x-ray spectroscopy(EDS), Fourier infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The analysis results confirmed that the particles were the expected ones. TiO2 was dispersed homogeneously within the spheroidal particles. Compared to the control gel, the composite gel particles not only contained Ti element but also showed higher thermal stability. In addition, the photo-catalytic behavior of the particles for the degradation of methyl orange contained in aqueous solution was examined. The particles exhibited photocatalytic characteristic for the degradation of the model dye, which could be modulated by simply varying the amount of cross-linking agent or TiO2. The photo-catalytic degradation percentage of methyl orange maintained at 91%-96% after using the particles three times, which indicated that TiO2 could played its role repeatedly via being fixated within polyvinyl alcohol-based gel.
基金supported by the French National Research Agency (No. ANR-13-IS09-0002-01)
文摘Ensembles of freeze-dried self-rolled polymer micro-scrolls are explored as template media for produc- ing carbon-iron based composites with fibrous morphology. Polymer fibres impregnated with furfuryl alcohol and loaded with Fe2O3 particles, were thermally treated under inert atmosphere at 700 ℃ and subsequently analysed by scanning and transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and nitrogen adsorption. The resulting material has a micro-fibrous mor- phology and is basically composed of metallic Fe^0 and FeO particles, i.e., more than 98 wt% of the carbon/ iron-based composite mass. These particles are held together by amorphous porous carbon foam obtained by in-situ carbonization of the polymer/Fe2O3 composite with evacuation of carbon from the system via COx gases released by carbo-reduction of Fe2O3. The material has significant activity in the reaction of catalytic decomposition of hydrogen peroxide in water solutions.
基金the National Natural Science Foundation of China(grant Nos.82360777 and 82003953)National Natural Science Foundation of Jiangxi Province(grant No.20232ACB216015)+3 种基金GanPo Yang Talent Support Plan(grant No.2025QT07)Jiangxi University of Chinese Medicine Science and Technology Innovation Team Development Program(grant No.CXTD-22004)Doctoral Research start-up Fund Project of Jiangxi University of Chinese Medicine(grant Nos.2021BSZR015 and2022BSzR003)Open fund project of Key Laboratory of Modern Preparation of TCM,Ministry of Education,Jiangxi University of Chinese Medicine(grant No.Zdsys-202302).
文摘This study aimed to compare and analyze the effects of different modifiers on the structure,free surface energy parameters,and direct compaction properties of composite particles(CPs)prepared by co-spray drying and to explore the correlation among structure,free surface energy parameters,and direct compaction properties of CPs.CPs with Puerariae lobatae radix were prepared by adding different modifiers.The structure,free surface energy parameters,and direct compaction properties of cPs were characterized.Furthermore,Pearson correlation analysis and artificial neural network methods were used to evaluate the correlation among structure,free surface energy parameters,and direct compaction properties of CPs.The results showed that different modifiers exhibited variegated effects on the structure,free surface energy parameters,and direct compaction properties of cPs.Pearson correlation analysis showed that the particle size distribution,uniformity,and brightness were positively correlated with polar components and polarity index,with statistical significance(P<0.01).The polar components and polarity index were positively correlated with flowability and disintegration time,and negatively correlated with compactibility,with statistical significance(P<0.o1).Overall,these findings contribute to better establishing a theoretical model among structure,free surface energy parameters,and direct compaction properties of Ps and provide a theoretical basis for predicting material properties.
基金the National Natural Science Foundation of China(52173206)the Applied Foundation Frontier Project from Wuhan Science and Technology Bureau(2022013988065202)。
文摘Room-temperature phosphorescence(RTP)materials play a vital role in security domain due to their unique optical properties.However,most average lifetimes of available RTP materials remain less than 1 s in aqueous-phase media,which is unfavorable to practical applications.Herein,an ex-situ covalent coupling strategy is proposed to fabricate liquid-phase long-lived RTP materials by combining SiO_(2)microspheres with the feather-derived carbon dots(CDs).Astonishingly,the aqueous dispersion of the resulting CDs@SiO_(2)microspheres exhibits a lifetime of up to 2.38 s with an absolute quantum yield of 22%.Moreover,the average lifetime of the solid CDs@SiO_(2)is as long as 3.04 s,which is superior to that of existing RTP carbon-based materials.The striking enhancements in the RTP of the CDs@SiO_(2)composites are mainly attributed to the immobilization of the formed Si–O–C covalent bonds and Si–O–Si rigid networks.The CDs@SiO_(2)composites were subsequently applied in the fields of information encryption and anti-fake.Interestingly,the CDs@SiO_(2)composites possess intriguing,reversible and stable optical properties,including water-responsive structural colors,blue fluorescence and cyan RTP,exhibiting excellent covert performance in applications of information encryption and decryption,and high-level anticounterfeiting.These findings provide not only a straightforward strategy for developing multiresponsive optical materials but also a more secure anticounterfeiting technology.
基金supported by the National Natural Science Foundations of China(21141001,51272151)by the Fundamental Research Funds for the Central Universities(GK20111004)
文摘TiO2@ZrO2@Y2O3 ：Eu3＋ composite particles with a core-multishell structure were synthesized through the combination of a layer-by-layer （LBL） self-assembly method and a sol-gel process. The obtained sam- ples were characterized with scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and fluorescence spectropho- tometry. The results showed that the composite particles had a core-multishell structure, spherical morphology, and a narrow size distribution. The presence of a ZrO2 layer on the TiO2 core can effec- tively prevent the reaction between the TiO2 core and a Y203 shell; the temperature for the reaction between the TiO2 core and the Y203 shell in the TiO2@ZrO2@Y2O3 ：Eu core-multishell phosphor can be elevated by 300 ℃ compared to that for TiO2@ZrO2：Eu. Upon excitation of the core-multishell particles in the ultraviolet （254 nm）, the Eu3＋ ion in the Y2O3 ：Eu3＋ shell shows its characteristic red emission （611 nm, 5D0→7F2）, and the photoluminescence （PL） intensity of the phosphor with the core-multishell structure was obviously greater than that of the core-shell TiO2@Y2O3 ：Eu phosphor.
