To enhance the Young’s modulus(E)and strength of titanium alloys,we designed titanium matrix composites with intercon-nected microstructure based on the Hashin-Shtrikman theory.According to the results,the in-situ re...To enhance the Young’s modulus(E)and strength of titanium alloys,we designed titanium matrix composites with intercon-nected microstructure based on the Hashin-Shtrikman theory.According to the results,the in-situ reaction yielded an interconnected microstructure composed of Ti_(2)C particles when the Ti_(2)C content reached 50vol%.With widths of 10 and 230 nm,the intraparticle Ti lamellae in the prepared composite exhibited a bimodal size distribution due to precipitation and the unreacted Ti phase within the grown Ti_(2)C particles.The composites with interconnected microstructure attained superior properties,including E of 174.3 GPa and ultimate flexural strength of 1014 GPa.Compared with that of pure Ti,the E of the composite was increased by 55% due to the high Ti_(2)C content and interconnected microstructure.The outstanding strength resulted from the strong interfacial bonding,load-bearing capacity of interconnected Ti_(2)C particles,and bimodal intraparticle Ti lamellae,which minimized the average crack driving force.Interrupted flexural tests revealed preferential crack initiation along the{001}cleavage plane and grain boundary of Ti_(2)C in the region with the highest tensile stress.In addition,the propagation can be efficiently inhibited by interparticle Ti grains,which prevented the brittle fracture of the composites.展开更多
This work aims at determining the overall response of a two-phase elastoplastic composite to isotropic loading. The composite under investigation consists of elastic particles embedded in an elastic perfectly plastic ...This work aims at determining the overall response of a two-phase elastoplastic composite to isotropic loading. The composite under investigation consists of elastic particles embedded in an elastic perfectly plastic matrix governed by the Mohr-Coulomb yield criterion and a non-associated plastic flow rule. The composite sphere assemblage model is adopted, and closed-form estimates are derived for the effective elastoplastic properties of the composite either under tensile or compressive isotropic loading. In the case when elastic particles reduce to voids, the composite in question degenerates into a porous elastoplastic material. The results obtained in the present work are of interest, in particular, for soil mechanics.展开更多
In recent years,environmental pollution and energy crisis have become increasingly serious issues owing to the burning of fossil fuels.Among the many technologies,decomposition of water to produce hydrogen has attract...In recent years,environmental pollution and energy crisis have become increasingly serious issues owing to the burning of fossil fuels.Among the many technologies,decomposition of water to produce hydrogen has attracted much attention because of its sustainability and non-polluting characteristic.However,highly efficient decomposition of water that is driven by visible light is still a challenge.Herein,we report the large-scale preparation of step-scheme porous graphite carbon nitride/Zn0.2Cd0.8S-diethylenetriamine(Pg-C3N4/Zn0.2Cd0.8S-DETA)composite by a facile solvothermal method.It was found by UV-vis spectroscopy that 15%Pg-C3N4/Zn0.2Cd0.8S-DETA exhibited suitable visible absorption edge and band gap for water decomposition.The hydrogen production rate of 15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite was 6.69 mmol g^-1 h^-1,which was 16.73,1.61,and 1.44 times greater than those of Pg-C3N4,CdS-DETA,and Zn0.2Cd0.8S-DETA,respectively.In addition,15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite displayed excellent photocatalytic stability,which was maintained for seven cycles of photocatalytic water splitting test.We believe that 15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite can be a valuable guide for the development of solar hydrogen production applications in the near future.展开更多
We have recently published a series of papers on a theory we call collision space-time, that seems to unify gravity and quantum mechanics. In this theory, mass and energy are redefined. We have not so far demonstrated...We have recently published a series of papers on a theory we call collision space-time, that seems to unify gravity and quantum mechanics. In this theory, mass and energy are redefined. We have not so far demonstrated how to make it compatible with electric properties such as charge and the Coulomb force. The aim of this paper is to show how electric properties can be reformulated to make it consistent with collision space-time. It is shown that we need to incorporate the Planck scale into the electric constants to do so. This is also fully possible from a practical point of view, as it has recently been shown how to measure the Planck length independent of other constants and without the need for dimensional analysis.展开更多
Modified Theories of Gravity include spin dependence in General Relativity, to account for additional sources of gravity instead of dark matter/energy approach. The spin-spin interaction is already included in the eff...Modified Theories of Gravity include spin dependence in General Relativity, to account for additional sources of gravity instead of dark matter/energy approach. The spin-spin interaction is already included in the effective nuclear force potential, and theoretical considerations and experimental evidence hint to the hypothesis that Gravity originates from such an interaction, under an averaging process over spin directions. This invites to continue the line of theory initiated by Einstein and Cartan, based on tetrads and spin effects modeled by connections with torsion. As a first step in this direction, the article considers a new modified Coulomb/Newton Law accounting for the spin-spin interaction. The physical potential is geometrized through specific affine connections and specific semi-Riemannian metrics, canonically associated to it, acting on a manifold or at the level of its tangent bundle. Freely falling particles in these “toy Universes” are determined, showing an interesting behavior and unexpected patterns.展开更多
Here,a new integrated machine learning and Chou’s pseudo amino acid composition method has been proposed for in silico epitope mapping of severe acute respiratorysyndrome-like coronavirus antigens.For this,a training...Here,a new integrated machine learning and Chou’s pseudo amino acid composition method has been proposed for in silico epitope mapping of severe acute respiratorysyndrome-like coronavirus antigens.For this,a training dataset including 266 linear B-cell epitopes,1,267 T-cell epitopes and 1,280 non-epitopes were prepared.The epitope sequences were then converted to numerical vectors using Chou’s pseudo amino acid composition method.The vectors were then introduced to the support vector machine,random forest,artificial neural network,and K-nearest neighbor algorithms for the classification process.The algorithm with the highest performance was selected for the epitope mapping procedure.Based on the obtained results,the random forest algorithm was the most accurate classifier with an accuracy of 0.934 followed by K-nearest neighbor,artificial neural network,and support vector machine respectively.Furthermore,the efficacies of predicted epitopes by the trained random forest algorithm were assessed through their antigenicity potential as well as affinity to human B cell receptor and MHC-I/II alleles using the VaxiJen score and molecular docking,respectively.It was also clear that the predicted epitopes especially the B-cell epitopes had high antigenicity potentials and good affinities to the protein targets.According to the results,the suggested method can be considered for developing specific epitope predictor software as well as an accelerator pipeline for designing serotype independent vaccine against the virus.展开更多
As we know, Coulomb’s law describes the interaction between static charges. In this paper, the modified formula of Coulomb’s law in the state of charge motion is given. Based on this formula, Ampere’s law and Lore...As we know, Coulomb’s law describes the interaction between static charges. In this paper, the modified formula of Coulomb’s law in the state of charge motion is given. Based on this formula, Ampere’s law and Lorentz’s law of force are derived by pure mathematics. According to the similarity between the formula of universal gravitation and Coulomb’s law, the correction of the formula of universal gravitation under the state of motion is assumed boldly, and some inferences are made on the motion law of celestial bodies.展开更多
The novel laminated Ti-TiBw/Ti composites composed of pure Ti layers and TiBw/Ti composite layers have been successfully fabricated by reactive hot pressing. Herein, two-scale structures formed： the pure Ti layer and...The novel laminated Ti-TiBw/Ti composites composed of pure Ti layers and TiBw/Ti composite layers have been successfully fabricated by reactive hot pressing. Herein, two-scale structures formed： the pure Ti layer and TiBw/Ti composite layer together constructed a laminated structure at a macro scale. Furthermore, TiBw reinforcement was distributed around Ti particles and then formed a network microstructure in TiBw/Ti composite layer at a micro scale. The laminated Ti-TiBw/Ti composites reveal a superior combination of high strength and high elongation due to two-scale structures compared with the pure Ti, and a further enhancement in ductility compared with the network structured composites. Moreover, the elastic modulus of the laminated composites can be predicted by H-S upper bound, which is consistent with the experimental values.展开更多
To get a dielectric material with a high dielectric permittivity and suppressed dielectric loss,nano-Ag with a particle size of 20 nm and Ag@TiO_(2)core-shell particles with diameters of approximately 70-120 nm were e...To get a dielectric material with a high dielectric permittivity and suppressed dielectric loss,nano-Ag with a particle size of 20 nm and Ag@TiO_(2)core-shell particles with diameters of approximately 70-120 nm were embedded in polyvinylidene fluoride(PVDF)to fabricate nano-Ag/Ag@TiO_(2)/PVDF composites.After being modified by nano-Ag with 3 vol%optimal amount,the relative permittivity(ε_r)at 100 Hz of 50 vol%Ag@TiO_(2)/PVDF composites was 61,and the dielectric loss can be suppressed to 0.04,almost 96.4%lower than that of unmodified composites,and a higher frequency stability of bothε_r and loss has also been found.The underlying mechanism of the reduced loss was attributed to Maxwell-Wagner polarization and the Coulomb blockade effect caused by the introduction of a small amount of nano-Ag,which will block the movement of electrons between metal nanoparticles and composites.The space charge polarization and conductance loss are weakened at lower and higher Ag@TiO_(2)filling ratios,respectively,thus leading to a very low loss of the composites.展开更多
The sawdust reinforced Acrylonitrile Butadiene Styrene (ABS) composites were prepared by using hot press molding machine for five different wt% (0%, 5%, 10%, 15% and 20%) at 180<span style="white-space:nowrap;...The sawdust reinforced Acrylonitrile Butadiene Styrene (ABS) composites were prepared by using hot press molding machine for five different wt% (0%, 5%, 10%, 15% and 20%) at 180<span style="white-space:nowrap;">°</span>C temperature and 50 KN load. Sawdust was collected from local saw mill of Savar, Dhaka, Bangladesh and ABS polymer was collected from local market of Dhaka, Bangladesh. In this study, different properties of composites like physical (bulk density and water absorption), mechanical (tensile properties and hardness) and structural (Fourier Transform Infrared Spectroscopy) properties were studied. The bulk density of composites was not altered consistently and it gave greater value for 5% and 20% composites. The water absorption enhanced for all composites with the accumulation of fiber content and soaking time. The reduction of tensile strength and Leeb’s rebound hardness of the composites were observed with the increase of the fiber content in all compositions. Maximum (%) of elongation was found for 5% composite, and then it gradually decreased;however, elastic modulus increased with the increased of fiber content in composites. Fourier Transform Infrared (FTIR) spectroscopy study was done for structural characterization. It was found that there was a new bond (C≡C) stretching formed for 20% composite;moreover, C-H rocking for 0% composite was broken for all other composites after the addition of sawdust in ABS polymer matrix.展开更多
The purpose of this study was to measure the amount of adsorption of various salivary proteins to a resin composite having various amounts of surface pre-reacted glass-ionomer (S-PRG) fillers, and to make a comparativ...The purpose of this study was to measure the amount of adsorption of various salivary proteins to a resin composite having various amounts of surface pre-reacted glass-ionomer (S-PRG) fillers, and to make a comparative study of the adherence of S. mutans to the resin composite covered by various salivary proteins. We experimentally produced resin composites (S-PRG resin) having the basic composition of Bis-GMA/TEGDMA and various amount of the S-PRG fillers ranging between 0 - 60 wt%. Each S-PRG resin block was soaked in 5 kinds of components found in salivary fluid (Mucin 1, Lactoferrin, IgA, Cystatin C, and Lysozyme), and the amount of adsorption was measured by use of a spectrophotometer. The amount of the adsorption of salivary Mucin 1 was higher than that of any other salivary component tested regardless of the percentage of the S-PRG filler. In the case of salivary Lysoxyme used for coating, the amount of its adsorption increased with an increase in the percentage of the S-PRG filler. In addition, resin blocks coated with various salivary proteins were incubated at 37℃ for 2 hours with radio-labeled S. mutans for a quantitative adherence test. Labeled bacteria that adhered to the resin blocks were collected by using an automatic sample combustion system and a liquid scintillation counter. The absorbed salivary components, especially Mucin 1 and Lysozyme, inhibited the adhesion of S. mutans to the S-PRG resin;however, these changes were generally directional rather than statistically significant.展开更多
基金financially supported by the National Key R&D Program of China(No.2021YFB3701203)the National Natural Science Foundation of China(Nos.U22A20113,52201116,52071116,and 52261135543)+1 种基金Heilongjiang Touyan Team ProgramChina Postdoctoral Science Foundation(No.2022M710939).
文摘To enhance the Young’s modulus(E)and strength of titanium alloys,we designed titanium matrix composites with intercon-nected microstructure based on the Hashin-Shtrikman theory.According to the results,the in-situ reaction yielded an interconnected microstructure composed of Ti_(2)C particles when the Ti_(2)C content reached 50vol%.With widths of 10 and 230 nm,the intraparticle Ti lamellae in the prepared composite exhibited a bimodal size distribution due to precipitation and the unreacted Ti phase within the grown Ti_(2)C particles.The composites with interconnected microstructure attained superior properties,including E of 174.3 GPa and ultimate flexural strength of 1014 GPa.Compared with that of pure Ti,the E of the composite was increased by 55% due to the high Ti_(2)C content and interconnected microstructure.The outstanding strength resulted from the strong interfacial bonding,load-bearing capacity of interconnected Ti_(2)C particles,and bimodal intraparticle Ti lamellae,which minimized the average crack driving force.Interrupted flexural tests revealed preferential crack initiation along the{001}cleavage plane and grain boundary of Ti_(2)C in the region with the highest tensile stress.In addition,the propagation can be efficiently inhibited by interparticle Ti grains,which prevented the brittle fracture of the composites.
文摘This work aims at determining the overall response of a two-phase elastoplastic composite to isotropic loading. The composite under investigation consists of elastic particles embedded in an elastic perfectly plastic matrix governed by the Mohr-Coulomb yield criterion and a non-associated plastic flow rule. The composite sphere assemblage model is adopted, and closed-form estimates are derived for the effective elastoplastic properties of the composite either under tensile or compressive isotropic loading. In the case when elastic particles reduce to voids, the composite in question degenerates into a porous elastoplastic material. The results obtained in the present work are of interest, in particular, for soil mechanics.
基金supported by the National Natural Science Foundation of China(51572103,51502106)the Distinguished Young Scholar of Anhui Province(1808085J14)+2 种基金the Foundation for Young Talents in College of Anhui Province(gxyqZD2017051)the Key Foundation of Educational Commission of Anhui Province(KJ2016SD53)Innovation Team of Design and Application of Advanced Energetic Materials(KJ2015TD003)~~
文摘In recent years,environmental pollution and energy crisis have become increasingly serious issues owing to the burning of fossil fuels.Among the many technologies,decomposition of water to produce hydrogen has attracted much attention because of its sustainability and non-polluting characteristic.However,highly efficient decomposition of water that is driven by visible light is still a challenge.Herein,we report the large-scale preparation of step-scheme porous graphite carbon nitride/Zn0.2Cd0.8S-diethylenetriamine(Pg-C3N4/Zn0.2Cd0.8S-DETA)composite by a facile solvothermal method.It was found by UV-vis spectroscopy that 15%Pg-C3N4/Zn0.2Cd0.8S-DETA exhibited suitable visible absorption edge and band gap for water decomposition.The hydrogen production rate of 15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite was 6.69 mmol g^-1 h^-1,which was 16.73,1.61,and 1.44 times greater than those of Pg-C3N4,CdS-DETA,and Zn0.2Cd0.8S-DETA,respectively.In addition,15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite displayed excellent photocatalytic stability,which was maintained for seven cycles of photocatalytic water splitting test.We believe that 15%Pg-C3N4/Zn0.2Cd0.8S-DETA composite can be a valuable guide for the development of solar hydrogen production applications in the near future.
文摘We have recently published a series of papers on a theory we call collision space-time, that seems to unify gravity and quantum mechanics. In this theory, mass and energy are redefined. We have not so far demonstrated how to make it compatible with electric properties such as charge and the Coulomb force. The aim of this paper is to show how electric properties can be reformulated to make it consistent with collision space-time. It is shown that we need to incorporate the Planck scale into the electric constants to do so. This is also fully possible from a practical point of view, as it has recently been shown how to measure the Planck length independent of other constants and without the need for dimensional analysis.
文摘Modified Theories of Gravity include spin dependence in General Relativity, to account for additional sources of gravity instead of dark matter/energy approach. The spin-spin interaction is already included in the effective nuclear force potential, and theoretical considerations and experimental evidence hint to the hypothesis that Gravity originates from such an interaction, under an averaging process over spin directions. This invites to continue the line of theory initiated by Einstein and Cartan, based on tetrads and spin effects modeled by connections with torsion. As a first step in this direction, the article considers a new modified Coulomb/Newton Law accounting for the spin-spin interaction. The physical potential is geometrized through specific affine connections and specific semi-Riemannian metrics, canonically associated to it, acting on a manifold or at the level of its tangent bundle. Freely falling particles in these “toy Universes” are determined, showing an interesting behavior and unexpected patterns.
文摘Here,a new integrated machine learning and Chou’s pseudo amino acid composition method has been proposed for in silico epitope mapping of severe acute respiratorysyndrome-like coronavirus antigens.For this,a training dataset including 266 linear B-cell epitopes,1,267 T-cell epitopes and 1,280 non-epitopes were prepared.The epitope sequences were then converted to numerical vectors using Chou’s pseudo amino acid composition method.The vectors were then introduced to the support vector machine,random forest,artificial neural network,and K-nearest neighbor algorithms for the classification process.The algorithm with the highest performance was selected for the epitope mapping procedure.Based on the obtained results,the random forest algorithm was the most accurate classifier with an accuracy of 0.934 followed by K-nearest neighbor,artificial neural network,and support vector machine respectively.Furthermore,the efficacies of predicted epitopes by the trained random forest algorithm were assessed through their antigenicity potential as well as affinity to human B cell receptor and MHC-I/II alleles using the VaxiJen score and molecular docking,respectively.It was also clear that the predicted epitopes especially the B-cell epitopes had high antigenicity potentials and good affinities to the protein targets.According to the results,the suggested method can be considered for developing specific epitope predictor software as well as an accelerator pipeline for designing serotype independent vaccine against the virus.
文摘As we know, Coulomb’s law describes the interaction between static charges. In this paper, the modified formula of Coulomb’s law in the state of charge motion is given. Based on this formula, Ampere’s law and Lorentz’s law of force are derived by pure mathematics. According to the similarity between the formula of universal gravitation and Coulomb’s law, the correction of the formula of universal gravitation under the state of motion is assumed boldly, and some inferences are made on the motion law of celestial bodies.
基金Funded by the National Natural Science Foundation of China(Nos.51101042,51271064 and 51228102)
文摘The novel laminated Ti-TiBw/Ti composites composed of pure Ti layers and TiBw/Ti composite layers have been successfully fabricated by reactive hot pressing. Herein, two-scale structures formed： the pure Ti layer and TiBw/Ti composite layer together constructed a laminated structure at a macro scale. Furthermore, TiBw reinforcement was distributed around Ti particles and then formed a network microstructure in TiBw/Ti composite layer at a micro scale. The laminated Ti-TiBw/Ti composites reveal a superior combination of high strength and high elongation due to two-scale structures compared with the pure Ti, and a further enhancement in ductility compared with the network structured composites. Moreover, the elastic modulus of the laminated composites can be predicted by H-S upper bound, which is consistent with the experimental values.
基金Funded by the National Natural Science Foundation of China(No.51772107)the Fundamental Research Funds for the Central Universities(No.2017KFYXJJ022)。
文摘To get a dielectric material with a high dielectric permittivity and suppressed dielectric loss,nano-Ag with a particle size of 20 nm and Ag@TiO_(2)core-shell particles with diameters of approximately 70-120 nm were embedded in polyvinylidene fluoride(PVDF)to fabricate nano-Ag/Ag@TiO_(2)/PVDF composites.After being modified by nano-Ag with 3 vol%optimal amount,the relative permittivity(ε_r)at 100 Hz of 50 vol%Ag@TiO_(2)/PVDF composites was 61,and the dielectric loss can be suppressed to 0.04,almost 96.4%lower than that of unmodified composites,and a higher frequency stability of bothε_r and loss has also been found.The underlying mechanism of the reduced loss was attributed to Maxwell-Wagner polarization and the Coulomb blockade effect caused by the introduction of a small amount of nano-Ag,which will block the movement of electrons between metal nanoparticles and composites.The space charge polarization and conductance loss are weakened at lower and higher Ag@TiO_(2)filling ratios,respectively,thus leading to a very low loss of the composites.
文摘The sawdust reinforced Acrylonitrile Butadiene Styrene (ABS) composites were prepared by using hot press molding machine for five different wt% (0%, 5%, 10%, 15% and 20%) at 180<span style="white-space:nowrap;">°</span>C temperature and 50 KN load. Sawdust was collected from local saw mill of Savar, Dhaka, Bangladesh and ABS polymer was collected from local market of Dhaka, Bangladesh. In this study, different properties of composites like physical (bulk density and water absorption), mechanical (tensile properties and hardness) and structural (Fourier Transform Infrared Spectroscopy) properties were studied. The bulk density of composites was not altered consistently and it gave greater value for 5% and 20% composites. The water absorption enhanced for all composites with the accumulation of fiber content and soaking time. The reduction of tensile strength and Leeb’s rebound hardness of the composites were observed with the increase of the fiber content in all compositions. Maximum (%) of elongation was found for 5% composite, and then it gradually decreased;however, elastic modulus increased with the increased of fiber content in composites. Fourier Transform Infrared (FTIR) spectroscopy study was done for structural characterization. It was found that there was a new bond (C≡C) stretching formed for 20% composite;moreover, C-H rocking for 0% composite was broken for all other composites after the addition of sawdust in ABS polymer matrix.
文摘The purpose of this study was to measure the amount of adsorption of various salivary proteins to a resin composite having various amounts of surface pre-reacted glass-ionomer (S-PRG) fillers, and to make a comparative study of the adherence of S. mutans to the resin composite covered by various salivary proteins. We experimentally produced resin composites (S-PRG resin) having the basic composition of Bis-GMA/TEGDMA and various amount of the S-PRG fillers ranging between 0 - 60 wt%. Each S-PRG resin block was soaked in 5 kinds of components found in salivary fluid (Mucin 1, Lactoferrin, IgA, Cystatin C, and Lysozyme), and the amount of adsorption was measured by use of a spectrophotometer. The amount of the adsorption of salivary Mucin 1 was higher than that of any other salivary component tested regardless of the percentage of the S-PRG filler. In the case of salivary Lysoxyme used for coating, the amount of its adsorption increased with an increase in the percentage of the S-PRG filler. In addition, resin blocks coated with various salivary proteins were incubated at 37℃ for 2 hours with radio-labeled S. mutans for a quantitative adherence test. Labeled bacteria that adhered to the resin blocks were collected by using an automatic sample combustion system and a liquid scintillation counter. The absorbed salivary components, especially Mucin 1 and Lysozyme, inhibited the adhesion of S. mutans to the S-PRG resin;however, these changes were generally directional rather than statistically significant.
