Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calcu...Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.展开更多
The first-principles calculation of the disordered Ll0 phase boundary for the Fe-Pd system is attempted by combining the FLAPW electronic structure total energy calculations and the cluster variation method via the cl...The first-principles calculation of the disordered Ll0 phase boundary for the Fe-Pd system is attempted by combining the FLAPW electronic structure total energy calculations and the cluster variation method via the cluster expansion method. The lattice vibration effects are taken into account based on the Debye-Gruneisen model within quasi-harmonic approximation. The transition temperature is reproduced with very high accuracy. However, the experimental congruent composition of disordered L10 phase that significantly deviates from 1.＂ 1 stoichiometry is not reproduced. Fulther calculations are attempted based on the phenomenological Lennard-Jones type pair potential, which is capable of introducing both tetragonality of the Ll0 ordered phase and additional configurational freedom because of the magnetic spins. The prelimi- nary calculations indicate that the tetragonality enhances the stability of the L10 ordered phase and the magnetic contributions also change the transition temperature. Despite these findings, the shift of the congruent composition still remains as a subject that needs further research. The electronic origin of the shifting of the congruent composition is briefly discussed.展开更多
Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy...Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy （MeV） and / or low energy （500 eV） ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.展开更多
A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they...A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they deviate from Franck-Condon approximation especially for the non-diagonal transitions. We also calculated the complete sets of vibrationally resolved cross sections for electron impact d3Ⅱu-X3Σg transition based on the semi-classical Gryzinski theory. An example of experimental study confirms that current approach provides a tool for a better diagnostics of H2 rovibrational distribution in electronic ground state.展开更多
The track induced by heavy ion irradiation on graphite has been systematically investigated over years, mainly motivated by the usage of graphite as a moderating and shielding material for nuclear reactors, or as a ta...The track induced by heavy ion irradiation on graphite has been systematically investigated over years, mainly motivated by the usage of graphite as a moderating and shielding material for nuclear reactors, or as a target for fragment separator in future's high-energy high-intensity beam facilities. Therefore it is important to understand the behavior of the thermal properties of graphite under the irradiation of energetic ions at high temperature.展开更多
Over the past three decades,a variety of complex structures mimicking intermetallic compounds have been discovered in soft matter systems.However,a complete understanding of the mechanisms that govern the self-assembl...Over the past three decades,a variety of complex structures mimicking intermetallic compounds have been discovered in soft matter systems.However,a complete understanding of the mechanisms that govern the self-assembly of these complex structures in aqueous solution is still lacking.Herein,we investigate the formation of mesoscale complex crystal structures with micelle packing of nonionic amphiphilic molecules in aqueous solutions using small-angle X-ray scattering(SAXS).The SAXS measurements revealed both unary-micelle and binary-micelles liquid crystalline phases,including face-centered cubic(FCC),body-centered cubic(BCC),Frank-Kasper(FK)σ,and FK A15 and NaZn_(13),FK C14,and FK C15 phases,respectively,which arise from the interplay of composition,temperature,and time.Quantitative SAXS analyses with Le Bail refinements and electron density reconstruction indicated that EO hydration,the interfacial curvature of micelles,and micellar packing play important roles in the formation of mesoscale complex crystalline structures during the self-assembly process of the nonionic ternary system.This study is the first demonstration of binary mesoscale complex crystalline structures with quasispherical close packing in nonionic amphiphilic aqueous solution,offering broader insights for the self-assembly mechanism of the complex crystalline structures on soft materials.展开更多
Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections,thrombosis,and intimal lesions caused by surface friction.However,achieving effective prevention of both bloodstream-...Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections,thrombosis,and intimal lesions caused by surface friction.However,achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities,specifically regarding electrostatic interactions.This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan(ZW@CMC)with antibacterial and antithrombotic activities for use in catheters.The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties,which facilitate the formation of a stable hydration layer with low friction.The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group.This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer.This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation.Subsequently,the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity,hemolysis,and catheter friction.Furthermore,in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment.This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices.展开更多
We have developed a process for chemical purification of carbon nanotubes for solution-processable thin-film transistors （TFTs） having high mobility. Films of the purified carbon nanotubes fabricated by simple drop ...We have developed a process for chemical purification of carbon nanotubes for solution-processable thin-film transistors （TFTs） having high mobility. Films of the purified carbon nanotubes fabricated by simple drop coating showed carrier mobilities as high as 164 cm2V-1s -1 normalized transconductances of 0.78 Sm-1 and on/off current ratios of 10^6. Such high performance requires the preparation of a suspension of micrometer-long and highly purified semiconducting single-walled carbon nanotubes （SWCNTs）. Our purification process includes length and electronic-type selective trapping of SWCNTs using recycling gel filtration with a mixture of surfactants. The results provide an important milestone toward printed high-speed and large-area electronics with roll-to-roll and ink-jet device fabrication.展开更多
We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161...We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161 MHz high repetition rate fiber laser using a single wall carbon nanotube was fabricated. The output pulse was amplified in an Er-doped single mode fiber amplifier, and a 1.1–2.2 μm wideband supercontinuum(SC) with an average power of 205 m W was generated in highly nonlinear fiber. The spectrogram of the generated SC was examined both experimentally and numerically. The generated SC was focused into a nonlinear crystal, and stable generation of MIR comb around the 3 μm wavelength region was realized.展开更多
文摘Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.
文摘The first-principles calculation of the disordered Ll0 phase boundary for the Fe-Pd system is attempted by combining the FLAPW electronic structure total energy calculations and the cluster variation method via the cluster expansion method. The lattice vibration effects are taken into account based on the Debye-Gruneisen model within quasi-harmonic approximation. The transition temperature is reproduced with very high accuracy. However, the experimental congruent composition of disordered L10 phase that significantly deviates from 1.＂ 1 stoichiometry is not reproduced. Fulther calculations are attempted based on the phenomenological Lennard-Jones type pair potential, which is capable of introducing both tetragonality of the Ll0 ordered phase and additional configurational freedom because of the magnetic spins. The prelimi- nary calculations indicate that the tetragonality enhances the stability of the L10 ordered phase and the magnetic contributions also change the transition temperature. Despite these findings, the shift of the congruent composition still remains as a subject that needs further research. The electronic origin of the shifting of the congruent composition is briefly discussed.
文摘Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of Kelvin probe （KP）, under He ion irradiation in high energy （MeV） and / or low energy （500 eV） ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.
基金The project supported by the University of Tokyo and partial supported by National Science Foundation of China (grants No.10135020 and 10275067)
文摘A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they deviate from Franck-Condon approximation especially for the non-diagonal transitions. We also calculated the complete sets of vibrationally resolved cross sections for electron impact d3Ⅱu-X3Σg transition based on the semi-classical Gryzinski theory. An example of experimental study confirms that current approach provides a tool for a better diagnostics of H2 rovibrational distribution in electronic ground state.
文摘The track induced by heavy ion irradiation on graphite has been systematically investigated over years, mainly motivated by the usage of graphite as a moderating and shielding material for nuclear reactors, or as a target for fragment separator in future's high-energy high-intensity beam facilities. Therefore it is important to understand the behavior of the thermal properties of graphite under the irradiation of energetic ions at high temperature.
基金supported by the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Educationthe National Research Foundation of Korea(NRF)+1 种基金the Commercialization Promotion Agency for R&D Outcomes(COMPA)grants funded by the Korean government(NRF-2020M2D6A1044636,NRF-2020R1I1A3A04036603,NRF-2021R1A6C101B383,RS-2023-00304743)supported by the BK21 FOUR Program by Jeonbuk National University Research Grant.
文摘Over the past three decades,a variety of complex structures mimicking intermetallic compounds have been discovered in soft matter systems.However,a complete understanding of the mechanisms that govern the self-assembly of these complex structures in aqueous solution is still lacking.Herein,we investigate the formation of mesoscale complex crystal structures with micelle packing of nonionic amphiphilic molecules in aqueous solutions using small-angle X-ray scattering(SAXS).The SAXS measurements revealed both unary-micelle and binary-micelles liquid crystalline phases,including face-centered cubic(FCC),body-centered cubic(BCC),Frank-Kasper(FK)σ,and FK A15 and NaZn_(13),FK C14,and FK C15 phases,respectively,which arise from the interplay of composition,temperature,and time.Quantitative SAXS analyses with Le Bail refinements and electron density reconstruction indicated that EO hydration,the interfacial curvature of micelles,and micellar packing play important roles in the formation of mesoscale complex crystalline structures during the self-assembly process of the nonionic ternary system.This study is the first demonstration of binary mesoscale complex crystalline structures with quasispherical close packing in nonionic amphiphilic aqueous solution,offering broader insights for the self-assembly mechanism of the complex crystalline structures on soft materials.
基金supported by the Korea Evaluation Institute of Industrial Technology(KEIT)grant funded by the South Korea government(MOTIE)(No.1415187426,RS-2023-00238181)supported by the institutional program funded by the Korea Institute of Industrial Technology(JA230007)the National Research Foundation of Korea(NRF)grant funded by the South Korea government(MSIT)(No.2022R1F1A1074255,No.RS-2022-00144435).
文摘Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections,thrombosis,and intimal lesions caused by surface friction.However,achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities,specifically regarding electrostatic interactions.This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan(ZW@CMC)with antibacterial and antithrombotic activities for use in catheters.The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties,which facilitate the formation of a stable hydration layer with low friction.The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group.This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer.This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation.Subsequently,the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity,hemolysis,and catheter friction.Furthermore,in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment.This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices.
文摘We have developed a process for chemical purification of carbon nanotubes for solution-processable thin-film transistors （TFTs） having high mobility. Films of the purified carbon nanotubes fabricated by simple drop coating showed carrier mobilities as high as 164 cm2V-1s -1 normalized transconductances of 0.78 Sm-1 and on/off current ratios of 10^6. Such high performance requires the preparation of a suspension of micrometer-long and highly purified semiconducting single-walled carbon nanotubes （SWCNTs）. Our purification process includes length and electronic-type selective trapping of SWCNTs using recycling gel filtration with a mixture of surfactants. The results provide an important milestone toward printed high-speed and large-area electronics with roll-to-roll and ink-jet device fabrication.
基金Japan Science and Technology Agency(JST)Japan Agency for Medical Research and Development(AMED)
文摘We demonstrated stable midinfrared(MIR) optical frequency comb at the 3.0 μm region with difference frequency generation pumped by a high power, Er-doped, ultrashort pulse fiber laser system. A soliton mode-locked161 MHz high repetition rate fiber laser using a single wall carbon nanotube was fabricated. The output pulse was amplified in an Er-doped single mode fiber amplifier, and a 1.1–2.2 μm wideband supercontinuum(SC) with an average power of 205 m W was generated in highly nonlinear fiber. The spectrogram of the generated SC was examined both experimentally and numerically. The generated SC was focused into a nonlinear crystal, and stable generation of MIR comb around the 3 μm wavelength region was realized.
