This study investigated the influence of the addition of Al to a Mg-7Bi(B7,wt%)alloy,particularly its recrystallization behavior during extrusion and its resulting mechanical properties.The addition of 2 wt%Al to the ...This study investigated the influence of the addition of Al to a Mg-7Bi(B7,wt%)alloy,particularly its recrystallization behavior during extrusion and its resulting mechanical properties.The addition of 2 wt%Al to the B7 alloy resulted in a lower grain size,a reduction in the number density of fine Mg3Bi2 particles,and a higher area fraction of relatively coarse Mg3Bi2 particles in the extrusion billet.These microstructural changes increased the nucleation sites for recrystallization,reduced the Zener pinning effect,and enhanced particle-stimulated nucleation,all of which promoted dynamic recrystallization behavior during extrusion.As a result,the area fraction of recrystallized grains in the extruded alloy increased from 77%to 94%.The extruded B7 alloy exhibited a strong<10-10>fiber texture,whereas the extruded Mg-7Bi-2Al(BA72)alloy had a weak<10-10>-<2-1-10>texture,which was attributed to the minimal presence of unrecrystallized grains and the dispersed orientation of the recrystallized grains.The tensile yield strength(TYS)of the extruded BA72 alloy was higher than that of the extruded B7 alloy(170 and 124 MPa,respectively),which resulted from the enhanced grain-boundary and solid-solution strengthening effects.The tensile elongation(EL)of the BA72 alloy also exceeded that of the B7 alloy(20.3%and 6.1%,respectively),the result of the uniform formation of fine twins under tension in the former and the formation of a few coarse twins among the unrecrystallized grains in the latter.Consequently,the addition of a small amount of Al to the B7 alloy significantly improved both the strength and ductility of the extruded alloy,resulting in a remarkable increase in the product of the TYS and EL from 756 to 3451 MPa%and expanding its potential range of applications as a lightweight extruded structural component.展开更多
This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn(AZ80)alloy.The alloy samples are compared after the application of 3.5%tension and 3.5%compr...This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn(AZ80)alloy.The alloy samples are compared after the application of 3.5%tension and 3.5%compression along the extrusion direction to induce slip-dominant and twinning-dominant deformation modes,respectively.The pre-compressed(PC)sample,which contained numerous{10-12}tension twins,has a reduced grain size and a higher internal strain than the pre-tensioned(PT)sample,which is attributed to the inherent internal strain that occurs during the formation and growth of the twins.As a result,the precipitation behavior of the PC sample is accelerated,leading to its short peak aging time of 32 h,which is lower than those of the PT and as-extruded samples(48 and 100 h,respectively).Furthermore,fine continuous precipitates(CPs)rapidly form within the{10-12}twins,contributing to the enhanced hardness.Discontinuous precipitates(DPs),which have a hardness comparable to the CP-containing twinned regions,in the PC sample experience less coarsening during aging than those in the PT sample due to growth inhibition by the{10-12}twins.Ultimately,the{10-12}twins generated under the twinning-dominant deformation condition lead to enhanced precipitation behaviors,including the preferential formation and refinement of CPs and the suppressed coarsening of DPs.Consequently,pre-deformation that occurs{10-12}twinning exhibits more pronounced effects on precipitation acceleration and microstructural modification than slip-inducing pre-deformation.展开更多
Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respective...Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.展开更多
Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst ...Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...展开更多
In this paper, we report the design and moleculardocking study of analogues of antimycin A3 as inhibitors of anti-apoptotic Bcl-2 of breast cancer. Twenty designed compounds and the original antimycin A3 were docked b...In this paper, we report the design and moleculardocking study of analogues of antimycin A3 as inhibitors of anti-apoptotic Bcl-2 of breast cancer. Twenty designed compounds and the original antimycin A3 were docked based on their interaction with breast tumor receptor binding target Bcl-2. The docking resulted in the five top-ranked compounds, namely, compounds 11, 14, 15, 16, and 20, which have a lower G binding energy, better affinity and stronger hydrogen bonding interactions to the active site of Bcl-2 than antimycin A3. Among those five top-ranked compounds, analogue compounds 11 and 14, which have an 18-membered tetralactone core and 18-membered tetraol core, respectively, exhibited the strongest hydrogen bond interaction, formed high stability conformation, and demonstrated the greatest inhibitory activity on the catalytic site of Bcl-2.展开更多
A method is described for creating a measurable unbalanced gravitational acceleration using a gravitomagnetic field surrounding a superconducting toroid. A gravitomagnetic toroid for unbalanced force production has be...A method is described for creating a measurable unbalanced gravitational acceleration using a gravitomagnetic field surrounding a superconducting toroid. A gravitomagnetic toroid for unbalanced force production has been experimentally realized as quite impractical. However recent advances in nanorod superconducting wire technology has enabled a new class of SMES devices operating at current densities and magnetic field strengths sufficient to develop measurable gravitomagnetic fields, while still maintaining mechanical integrity. It is proposed that an experimental SMES toroid configuration uses an absolute quantum gravimeter to measure acceleration fields along the axis of symmetry of a toroidal coil, thus providing experimental confirmation of the additive nature of the gravitomagnetic fields, as well as the production of a linear component of the overall acceleration field. In the present paper relativistic enhancement of this effect is also explored, as well as alternating current (AC) operations of the superconducting toroid to create gravitational waves. Lorentz force concerns are also addressed in Appendix.展开更多
Several authors have shown the beneficial role to incorporate silicon into hydroxyapatite lattice, although, the mechanism behind the enhanced bioactivity of this Si-hydroxyapatite (Si-HA) is poorly understood. The in...Several authors have shown the beneficial role to incorporate silicon into hydroxyapatite lattice, although, the mechanism behind the enhanced bioactivity of this Si-hydroxyapatite (Si-HA) is poorly understood. The incorporation of Si into the HA lattice alters the surface charge of HA, leading to more negative values. Due to the importance of the surface properties on the interaction between biomaterials, physiological fluids, and the host tissue, it is important to further characterize the surface of Si-HA by determining its surface energy and wettability. Our results showed that the incorporation of Si increased the hydrophilicity of HA, leading to a higher interfacial tension. Another important property for osteointegration is the formation of an apatite layer. The dissolution of Si-HA in the presence of serum-free simulated body fluid (SBF) started at early time points and using atomic force microscopy (AFM) it was possible to observe the dissolution at the grain boundaries and grains, therefore an apatite layer was formed in a short period of time. As the dissolution-precipitation process is much more complex in vivo, we tried to mimic the initial stages of the in vivo reaction by incubating the Si-HA in serum-SBF. It was shown that the dissolution kinetics in serum-SBF was slower when compared to the dissolution in serum free-SBF. At the same time point, no significant dissolution features were observed or apatite layer was visualized. The phase imaging AFM indicated the presence of a layer on top of these materials that could be a proteinaceous layer, as XPS analysis detected an increase on the concentration of nitrogen on the surface of the samples incubated in the presence of proteins.展开更多
Owing to their attractive structure and mechanical properties,high-entropy alloys(HEAs) and mediumentropy alloys(MEAs) have attracted considerable research interest.The strength of HEAs/MEAs with a single face-centere...Owing to their attractive structure and mechanical properties,high-entropy alloys(HEAs) and mediumentropy alloys(MEAs) have attracted considerable research interest.The strength of HEAs/MEAs with a single face-centered cubic(FCC) phase,on the other hand,requires improvement.Therefore,in this study,we demonstrate a strategy for increasing the room-temperature strength of FCC-phase HEAs/MEAs by tuning cryo-pre-straining-induced crystal defects via the temperature-dependent stacking fault energyregulated plasticity mechanism.Through neutron diffraction line profile analysis and electron microscope observation,the effect of the tuned defects on the tensile strength was clarified.Due to the cryorolling-induced high dislocation density,mechanical twins,and stacking faults,the room-temperature yield strength of an equiatomic CoCrFeNi HEA was increased by ~290%,from 243 MPa(as-recrystallized)to 941.6 MPa(30% cryo-rolled),while maintaining a tensile elongation of 18%.After partial recovery via heat treatment,the yield strength and ultimate tensile strength decreased slightly to 869 and 936 MPa,respectively.Conversely,the elongation increased to 25.6%,The dislocation density and distribution of the dislocations were found to contribute to the strengthening caused by forest dislocations,which warrants further investigation.This study discussed the possibility of developing single-phase high-performance HEAs by tuning pre-straining-induced crystal defects.展开更多
The suspensions of the powder mixture of yttria and alumina were prepared by the aqueous tape casting method. Rodia DP270, Dolapix CE64, citric acid and Dammonium 3008 were used as dispersing agents. The morphologies ...The suspensions of the powder mixture of yttria and alumina were prepared by the aqueous tape casting method. Rodia DP270, Dolapix CE64, citric acid and Dammonium 3008 were used as dispersing agents. The morphologies of the powders and the fracture surface of the green body were observed by scanning electron microscopy （SEM）. The zeta potential test was employed to characterize the surface charge states of different suspensions. The dispersion of the suspensions was analyzed by the rheological tests and the sedimentation experiments. The results indicated that the yttria and alumina powder mixtures were well dispersed by the dis- persing agents. The rheological curves showed shear thinning behavior. The most efficient dispersing agent was Dammonium 3008. The optimum usage of Dammonium 3008 was 1.0 wt.%. The green body was dense and no interface between the adjacent layers was found. The in-line transmittance of the as-sintered YAG ceramic was higher than 80% between 400 and 1100 urn.展开更多
Nd-doped SrA1204 （Nd：SrA1204） crystals were prepared by a floating zone （FZ） method with different dopant concentra- tions. The photoluminescence （PL） measurements under visible light excitations confirmed stro...Nd-doped SrA1204 （Nd：SrA1204） crystals were prepared by a floating zone （FZ） method with different dopant concentra- tions. The photoluminescence （PL） measurements under visible light excitations confirmed strong near infrared （NIR） emissions around 890 nm, which is due to the 4f-4f transitions of Nd3＋, and the decay time constants were 300-400 μs. Furthermore, VUV ex- citations revealed two broad emissions around 250450 and 500-700 run, which were attributed to self-trapped excitons （STEs） perturbed by Nd3＋. Moreover, the X-ray induced scintillation spectra showed some small peaks at around 380 nm in addition to NIR emissions at 1064 nm similarly seen in PL. The former scintillation decay time constants were 30-40 Its. In the undoped sample, these emissions mentioned above were not present but a weak broad emission around 450 nm appeared. In thermally stimulated lu- minescence （TSL） after X-ray irradiation, strong TSL glow peaks were observed in the Nd-doped samples at around 100 and 250 ℃.展开更多
The luminescence properties of Ce- or Ce and La-doped gadolinium pyrosilicate （Gd2Si2OT, GPS） were characterized using vacuum ultraviolet （VUV） excitation light. A prominent emission band was observed in the lumin...The luminescence properties of Ce- or Ce and La-doped gadolinium pyrosilicate （Gd2Si2OT, GPS） were characterized using vacuum ultraviolet （VUV） excitation light. A prominent emission band was observed in the luminescence spectra with excitation at 60 nm and ascribed to 5d-4f transition of Ce3＋. Because the excitation wavelength of 60 nm corresponded to the excitation in the host matrix, this result indicated that the excitation energy transfer occurred from the host matrix to Ce3＋ ions. On the basis of the rise in the luminescence time profiles with excitation at 60 nm, the energy transfer occurred within 2 ns, which was much shorter than that of Ce-doped Gd2SiO2. For Ce-doped GPS, the decay rate was slower for the host excitation than that for direct excitation of Ce3＋. In contrast, for Ce and La-doped GPS, no significant difference was observed for the host excitation and direct excitation of Ce3＋. This result indicated that the energy transfer from the host to Ce3＋ ions led to a different radiative decay process, and that La doping had an effect on the energy transfer and decay process.展开更多
Tb-doped 12CaO·7Al_2O_3（Tb：C12A7） crystals were synthesized by the floating zone（FZ） method and the photoluminescence（PL）, scintillation and thermally-stimulated luminescence（TSL） properties were investi...Tb-doped 12CaO·7Al_2O_3（Tb：C12A7） crystals were synthesized by the floating zone（FZ） method and the photoluminescence（PL）, scintillation and thermally-stimulated luminescence（TSL） properties were investigated. The photoluminescence（PL） emission spectra and PL decay time profiles were investigated by using Quantaurus-tau（Hamamatsu）. The scintillation spectra and decay time profiles were measured by using our laboratory-constructed set-up under X-ray irradiation. Finally, TSL glow curve was measured by using Nanogray TL-2000 with the heating rate of 1 °C/s. In PL and scintillation, emission peaks were observed at 493, 543, 587 and 620 nm due to the 4f-4f transitions of Tb3~＋. Decay time constants of the emission by PL and scintillation appeared to be different, and the measured values were approximately 2.4 and 1.9 ms, respectively. After X-ray irradiations, the 0.5%（all Tb contents in this paper are in mole fraction） and 1.0% Tb-doped samples showed a single intense and broad glow peak around 100 oC while 1.2%–1.5% Tb-doped samples showed notable additional peak around 250 oC.展开更多
This study describes the development of a one-pot strategy to produce spherical alloy microparticles for advanced near-net-shape manufacturing processes, including additive manufacturing and powder injection molding. ...This study describes the development of a one-pot strategy to produce spherical alloy microparticles for advanced near-net-shape manufacturing processes, including additive manufacturing and powder injection molding. The Al Si12 eutectic alloy(ca. 12 wt% Si) system was chosen as the model with which the main experiments were carried out. The proposed process synergistically integrates a few common,low-cost processing techniques including the mixing of Al micrometer size particles with silicon and sodium chloride, heat-treating the mixture at temperatures of 650–810°C, and the dissolution of salt in water to produce spherical Al Si12 alloy particles without the need to rely on costly melting and atomizing techniques. This new process can use laow-cost source Al and Si powders as the raw materials to produce10–200 um-sized spherical particles of Al Si12. The Ansys-CFX computational fluid dynamics software was used to analyze the flow behavior of Al Si12 liquid droplets and particle size refinement in the narrow voids of the sample.展开更多
(GdCa)(SiO)Oapatite crystals doped with different concentrations of Ce were synthesized by the Floating Zone(FZ) method, and we have evaluated the photoluminescence(PL) and radio luminescence(RL) properties. In PL, an...(GdCa)(SiO)Oapatite crystals doped with different concentrations of Ce were synthesized by the Floating Zone(FZ) method, and we have evaluated the photoluminescence(PL) and radio luminescence(RL) properties. In PL, an emission band appeared around 400 nm under excitation at 300 nm due to the5 d-4 f transitions of Ce3+. The PL decay curves were approximated by a second-order exponential decay function, and the derived decay time constants ranged around 20-25 ns and 40-480 ns. Similar emission was observed in RL, but the decay time constants were much longer than those in PL. The RL afterglow was the lowest in the 1.0% Ce-doped sample. The 1.0% and 2.0% Ce-doped samples showed a full-energy peak in the pulse height spectrum measured underAm 5.5 MeV α-ray irradiation, and the absolute scintillation light yields were estimated to be around 55 and 36 ph/5.5 MeV-a, respectively.展开更多
1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability...1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability constants reached a range of 1011 to 1012 M-1 in nonpolar solvents,it allowed construction of stable structures such as special pair of photosynthetic reaction center and light-harvesting antenna complex of photosynthetic bacteria.Here,we report one-dimensional array of porphyrin for the d...展开更多
To gain an understanding of the toxicity of antimicrobial polymers to human cells, their hemolytic action was investigated using human red blood cells （RBCs）. We examined the hemolysis induced by cationic amphiphili...To gain an understanding of the toxicity of antimicrobial polymers to human cells, their hemolytic action was investigated using human red blood cells （RBCs）. We examined the hemolysis induced by cationic amphiphilic methacrylate random copolymers, which have amino ethyl sidechains as cationic units and either butyl or methyl methacpjlate as hydrophobic units. The polymer with 30 tool% butyl sidechains （B3o） displayed higher hemolytic toxicity than the polymer with 59 tool% methyl sidechains （Ms9）. B3o also induced faster release of hemoglobin from RBCs than lVlsg. A new theoretical model is proposed based on two consecutive steps to form active polymer species on the RBC membranes, which are associated to RBC lysis. This model takes the all-or-none release of hemoglobin by the rupture of RBCs into account, providing new insight into the polymer-induced hemolysis regarding how individual or collective ceils respond to the polymers.展开更多
Radio-photoluminescence （RPL） is a phenomenon seen in luminescent materials in which the appearance of new photolu- minescence （PL） emission is induced by an incident ionizing radiation such as X-rays; and the sig...Radio-photoluminescence （RPL） is a phenomenon seen in luminescent materials in which the appearance of new photolu- minescence （PL） emission is induced by an incident ionizing radiation such as X-rays; and the signal is stable even after the irradia- tion and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in ra- diation measurements. The distinct advantage of RPL over the conventional thermally- or photo-stimulated luminescence （abbrevi- ated as TSL or PSL） dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple time without signal fading. In this work, we discovered that CsBr：Sm showed an RPL phenomenon by X-ray irradiation, and we characterized this new material as an RPL detector. While the sample showed PL emissions mainly in the visible range, after an X-ray irradiation additional emissions could be observed in the red to near-infrared range around 650-850 nm and 900-1000 nm and longer. The RPL response was fairly stable overall, but very interestingly the 650-850 nm signal slightly increased while the 900-1000 nm decreased during PL readout. The dynamic range was confirmed over 1-104 mGy with linear response.展开更多
基金supported by the Materials and Components Technology Development Program(No.20024843)funded by the Ministry of Trade,Industry,and Energy(MOTIE,South Korea)+1 种基金the National Research Foundation of Korea(NRF)grant(No.RS-2023-00244478)funded by the Ministry of Science,ICT,and Future Planning(MSIP,South Korea).
文摘This study investigated the influence of the addition of Al to a Mg-7Bi(B7,wt%)alloy,particularly its recrystallization behavior during extrusion and its resulting mechanical properties.The addition of 2 wt%Al to the B7 alloy resulted in a lower grain size,a reduction in the number density of fine Mg3Bi2 particles,and a higher area fraction of relatively coarse Mg3Bi2 particles in the extrusion billet.These microstructural changes increased the nucleation sites for recrystallization,reduced the Zener pinning effect,and enhanced particle-stimulated nucleation,all of which promoted dynamic recrystallization behavior during extrusion.As a result,the area fraction of recrystallized grains in the extruded alloy increased from 77%to 94%.The extruded B7 alloy exhibited a strong<10-10>fiber texture,whereas the extruded Mg-7Bi-2Al(BA72)alloy had a weak<10-10>-<2-1-10>texture,which was attributed to the minimal presence of unrecrystallized grains and the dispersed orientation of the recrystallized grains.The tensile yield strength(TYS)of the extruded BA72 alloy was higher than that of the extruded B7 alloy(170 and 124 MPa,respectively),which resulted from the enhanced grain-boundary and solid-solution strengthening effects.The tensile elongation(EL)of the BA72 alloy also exceeded that of the B7 alloy(20.3%and 6.1%,respectively),the result of the uniform formation of fine twins under tension in the former and the formation of a few coarse twins among the unrecrystallized grains in the latter.Consequently,the addition of a small amount of Al to the B7 alloy significantly improved both the strength and ductility of the extruded alloy,resulting in a remarkable increase in the product of the TYS and EL from 756 to 3451 MPa%and expanding its potential range of applications as a lightweight extruded structural component.
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(Nos.RS-2024-00351052 and RS-2024-00450561).
文摘This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn(AZ80)alloy.The alloy samples are compared after the application of 3.5%tension and 3.5%compression along the extrusion direction to induce slip-dominant and twinning-dominant deformation modes,respectively.The pre-compressed(PC)sample,which contained numerous{10-12}tension twins,has a reduced grain size and a higher internal strain than the pre-tensioned(PT)sample,which is attributed to the inherent internal strain that occurs during the formation and growth of the twins.As a result,the precipitation behavior of the PC sample is accelerated,leading to its short peak aging time of 32 h,which is lower than those of the PT and as-extruded samples(48 and 100 h,respectively).Furthermore,fine continuous precipitates(CPs)rapidly form within the{10-12}twins,contributing to the enhanced hardness.Discontinuous precipitates(DPs),which have a hardness comparable to the CP-containing twinned regions,in the PC sample experience less coarsening during aging than those in the PT sample due to growth inhibition by the{10-12}twins.Ultimately,the{10-12}twins generated under the twinning-dominant deformation condition lead to enhanced precipitation behaviors,including the preferential formation and refinement of CPs and the suppressed coarsening of DPs.Consequently,pre-deformation that occurs{10-12}twinning exhibits more pronounced effects on precipitation acceleration and microstructural modification than slip-inducing pre-deformation.
文摘Improved photovoltaic performance of perovskite solar cells is demonstrated through the synergistic effect of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as electron and hole-transporting layers,respectively. Highly crystalline ZnO nanorods were obtained by electrochemical deposition in a chloride medium. Additionally, rubrene interlayer was able to passivate or cover the grain boundaries of perovskite film effectively that led to reduced leakage current. A perovskite solar cell optimized with ZnO nanorods and rubrene：P3HT bilayer achieved a maximum efficiency of 4.9% showing reduced hysteresis behavior compared with the device having P3HT as the only hole-transporting layer. The application of longer nanorods led to better perovskite infiltration and shorter charge carrier path length. These results highlight the potential of electrodeposited ZnO nanorods and rubrene：P3HT bilayer as charge selective layers for efficient perovskite solar cells.
基金Grant-in-Aid for Scientific Research(B)from the Japan Society for the Promotion of Science(JSPS,No.18350055).
文摘Precise,efficient copolymerizations of ethylene with cyclic olefins[norbornene(NBE),cyclopentene(CPE)]using nonbridged half-titanocenes of type,Cp TiCl_2(L)(Cp =cyclopentadienyl group,L=aryloxo,ketimide)-MAO catalyst systems have been summarized.CpTiCl_2(N=C Bu_2)exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization:the NBE incorporation by Cp TiCl_2(X)(X=N=C Bu_2,O-2,6- Pr_2C_6H_3; Cp =Cp,C_5Me_5,indenyl)was related to the calculated coordination ene...
文摘In this paper, we report the design and moleculardocking study of analogues of antimycin A3 as inhibitors of anti-apoptotic Bcl-2 of breast cancer. Twenty designed compounds and the original antimycin A3 were docked based on their interaction with breast tumor receptor binding target Bcl-2. The docking resulted in the five top-ranked compounds, namely, compounds 11, 14, 15, 16, and 20, which have a lower G binding energy, better affinity and stronger hydrogen bonding interactions to the active site of Bcl-2 than antimycin A3. Among those five top-ranked compounds, analogue compounds 11 and 14, which have an 18-membered tetralactone core and 18-membered tetraol core, respectively, exhibited the strongest hydrogen bond interaction, formed high stability conformation, and demonstrated the greatest inhibitory activity on the catalytic site of Bcl-2.
文摘A method is described for creating a measurable unbalanced gravitational acceleration using a gravitomagnetic field surrounding a superconducting toroid. A gravitomagnetic toroid for unbalanced force production has been experimentally realized as quite impractical. However recent advances in nanorod superconducting wire technology has enabled a new class of SMES devices operating at current densities and magnetic field strengths sufficient to develop measurable gravitomagnetic fields, while still maintaining mechanical integrity. It is proposed that an experimental SMES toroid configuration uses an absolute quantum gravimeter to measure acceleration fields along the axis of symmetry of a toroidal coil, thus providing experimental confirmation of the additive nature of the gravitomagnetic fields, as well as the production of a linear component of the overall acceleration field. In the present paper relativistic enhancement of this effect is also explored, as well as alternating current (AC) operations of the superconducting toroid to create gravitational waves. Lorentz force concerns are also addressed in Appendix.
基金The authors acknowledge Fundacao para a Ciencia e Tecnologia,Portugal,for supporting Claudia Botelho grant(SFRHBPD/20987/2004).
文摘Several authors have shown the beneficial role to incorporate silicon into hydroxyapatite lattice, although, the mechanism behind the enhanced bioactivity of this Si-hydroxyapatite (Si-HA) is poorly understood. The incorporation of Si into the HA lattice alters the surface charge of HA, leading to more negative values. Due to the importance of the surface properties on the interaction between biomaterials, physiological fluids, and the host tissue, it is important to further characterize the surface of Si-HA by determining its surface energy and wettability. Our results showed that the incorporation of Si increased the hydrophilicity of HA, leading to a higher interfacial tension. Another important property for osteointegration is the formation of an apatite layer. The dissolution of Si-HA in the presence of serum-free simulated body fluid (SBF) started at early time points and using atomic force microscopy (AFM) it was possible to observe the dissolution at the grain boundaries and grains, therefore an apatite layer was formed in a short period of time. As the dissolution-precipitation process is much more complex in vivo, we tried to mimic the initial stages of the in vivo reaction by incubating the Si-HA in serum-SBF. It was shown that the dissolution kinetics in serum-SBF was slower when compared to the dissolution in serum free-SBF. At the same time point, no significant dissolution features were observed or apatite layer was visualized. The phase imaging AFM indicated the presence of a layer on top of these materials that could be a proteinaceous layer, as XPS analysis detected an increase on the concentration of nitrogen on the surface of the samples incubated in the presence of proteins.
基金supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science(JSPS)KAKENHI(Nos.19K14838 and 21K03766)the“Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development”project。
文摘Owing to their attractive structure and mechanical properties,high-entropy alloys(HEAs) and mediumentropy alloys(MEAs) have attracted considerable research interest.The strength of HEAs/MEAs with a single face-centered cubic(FCC) phase,on the other hand,requires improvement.Therefore,in this study,we demonstrate a strategy for increasing the room-temperature strength of FCC-phase HEAs/MEAs by tuning cryo-pre-straining-induced crystal defects via the temperature-dependent stacking fault energyregulated plasticity mechanism.Through neutron diffraction line profile analysis and electron microscope observation,the effect of the tuned defects on the tensile strength was clarified.Due to the cryorolling-induced high dislocation density,mechanical twins,and stacking faults,the room-temperature yield strength of an equiatomic CoCrFeNi HEA was increased by ~290%,from 243 MPa(as-recrystallized)to 941.6 MPa(30% cryo-rolled),while maintaining a tensile elongation of 18%.After partial recovery via heat treatment,the yield strength and ultimate tensile strength decreased slightly to 869 and 936 MPa,respectively.Conversely,the elongation increased to 25.6%,The dislocation density and distribution of the dislocations were found to contribute to the strengthening caused by forest dislocations,which warrants further investigation.This study discussed the possibility of developing single-phase high-performance HEAs by tuning pre-straining-induced crystal defects.
基金supported by National Natural Science Foundation of China(51002172,90122035)the Development Program of China(2010AA03015887003)
文摘The suspensions of the powder mixture of yttria and alumina were prepared by the aqueous tape casting method. Rodia DP270, Dolapix CE64, citric acid and Dammonium 3008 were used as dispersing agents. The morphologies of the powders and the fracture surface of the green body were observed by scanning electron microscopy （SEM）. The zeta potential test was employed to characterize the surface charge states of different suspensions. The dispersion of the suspensions was analyzed by the rheological tests and the sedimentation experiments. The results indicated that the yttria and alumina powder mixtures were well dispersed by the dis- persing agents. The rheological curves showed shear thinning behavior. The most efficient dispersing agent was Dammonium 3008. The optimum usage of Dammonium 3008 was 1.0 wt.%. The green body was dense and no interface between the adjacent layers was found. The in-line transmittance of the as-sintered YAG ceramic was higher than 80% between 400 and 1100 urn.
基金Project supported by the Aid for Scientific Research((A)-26249147)from the Ministry of Education,Culture,Sports,Science and Technology of the Japanese government(MEXT)JST A-step,Green Photonics Research from MEXT+2 种基金the Adaptable and Seamless Technology Transfer Program(A-STEP)by the Japan Science and Technology(JST)Agencythe Murata Science Foundationa cooperative research project of the Research Institute of Electronics,Shizuoka University
文摘Nd-doped SrA1204 （Nd：SrA1204） crystals were prepared by a floating zone （FZ） method with different dopant concentra- tions. The photoluminescence （PL） measurements under visible light excitations confirmed strong near infrared （NIR） emissions around 890 nm, which is due to the 4f-4f transitions of Nd3＋, and the decay time constants were 300-400 μs. Furthermore, VUV ex- citations revealed two broad emissions around 250450 and 500-700 run, which were attributed to self-trapped excitons （STEs） perturbed by Nd3＋. Moreover, the X-ray induced scintillation spectra showed some small peaks at around 380 nm in addition to NIR emissions at 1064 nm similarly seen in PL. The former scintillation decay time constants were 30-40 Its. In the undoped sample, these emissions mentioned above were not present but a weak broad emission around 450 nm appeared. In thermally stimulated lu- minescence （TSL） after X-ray irradiation, strong TSL glow peaks were observed in the Nd-doped samples at around 100 and 250 ℃.
基金supported by the Joint Studies Program (2014, No. 26–546) of the Institute for Molecular Sciencesupported by the SPRITS program, Kyoto Universitythe Cooperative Research Project of Research Institute of Electronics, Shizuoka University
文摘The luminescence properties of Ce- or Ce and La-doped gadolinium pyrosilicate （Gd2Si2OT, GPS） were characterized using vacuum ultraviolet （VUV） excitation light. A prominent emission band was observed in the luminescence spectra with excitation at 60 nm and ascribed to 5d-4f transition of Ce3＋. Because the excitation wavelength of 60 nm corresponded to the excitation in the host matrix, this result indicated that the excitation energy transfer occurred from the host matrix to Ce3＋ ions. On the basis of the rise in the luminescence time profiles with excitation at 60 nm, the energy transfer occurred within 2 ns, which was much shorter than that of Ce-doped Gd2SiO2. For Ce-doped GPS, the decay rate was slower for the host excitation than that for direct excitation of Ce3＋. In contrast, for Ce and La-doped GPS, no significant difference was observed for the host excitation and direct excitation of Ce3＋. This result indicated that the energy transfer from the host to Ce3＋ ions led to a different radiative decay process, and that La doping had an effect on the energy transfer and decay process.
基金supported by a Grant-in-Aid for Scientific Research(A)26249147 from the Ministry of Education,Culture,Sports,Science and Technology of Japan(MEXT),JST A-step,Cooperative Research Project of Research Institute of Electronics,Shizuoka University,Inamori foundation,KRF foundation
文摘Tb-doped 12CaO·7Al_2O_3（Tb：C12A7） crystals were synthesized by the floating zone（FZ） method and the photoluminescence（PL）, scintillation and thermally-stimulated luminescence（TSL） properties were investigated. The photoluminescence（PL） emission spectra and PL decay time profiles were investigated by using Quantaurus-tau（Hamamatsu）. The scintillation spectra and decay time profiles were measured by using our laboratory-constructed set-up under X-ray irradiation. Finally, TSL glow curve was measured by using Nanogray TL-2000 with the heating rate of 1 °C/s. In PL and scintillation, emission peaks were observed at 493, 543, 587 and 620 nm due to the 4f-4f transitions of Tb3~＋. Decay time constants of the emission by PL and scintillation appeared to be different, and the measured values were approximately 2.4 and 1.9 ms, respectively. After X-ray irradiations, the 0.5%（all Tb contents in this paper are in mole fraction） and 1.0% Tb-doped samples showed a single intense and broad glow peak around 100 oC while 1.2%–1.5% Tb-doped samples showed notable additional peak around 250 oC.
基金supported by the Technology Innovation Program(10063427,development of eco-friendly smelting technology for the production of rare metal production for lowering manufacturing costs using solid oxide membrane)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)the Competency Development Program for Industry Specialists of the Korean Ministry of Trade,Industry and Energy(MOTIE),operated by Korea Institute for Advancement of Technology(KIAT).(No.P0002019,HRD Program for High Value-Added Metallic Material Expert)supported by the Basic Research Laboratory Program through the Ministry of Education of the Republic of Korea(2019R1A4A1026125)。
文摘This study describes the development of a one-pot strategy to produce spherical alloy microparticles for advanced near-net-shape manufacturing processes, including additive manufacturing and powder injection molding. The Al Si12 eutectic alloy(ca. 12 wt% Si) system was chosen as the model with which the main experiments were carried out. The proposed process synergistically integrates a few common,low-cost processing techniques including the mixing of Al micrometer size particles with silicon and sodium chloride, heat-treating the mixture at temperatures of 650–810°C, and the dissolution of salt in water to produce spherical Al Si12 alloy particles without the need to rely on costly melting and atomizing techniques. This new process can use laow-cost source Al and Si powders as the raw materials to produce10–200 um-sized spherical particles of Al Si12. The Ansys-CFX computational fluid dynamics software was used to analyze the flow behavior of Al Si12 liquid droplets and particle size refinement in the narrow voids of the sample.
基金Project supported by a Grant-in-Aid for Scientific Research(A) 26249147 from the Ministry of Education,Culture,Sports,Science and Technology of Japan(MEXT)JST A-step,Cooperative Research Project of Research Institute of Electronics,Shizuoka University+1 种基金Inamori FoundationKRF Foundation
文摘(GdCa)(SiO)Oapatite crystals doped with different concentrations of Ce were synthesized by the Floating Zone(FZ) method, and we have evaluated the photoluminescence(PL) and radio luminescence(RL) properties. In PL, an emission band appeared around 400 nm under excitation at 300 nm due to the5 d-4 f transitions of Ce3+. The PL decay curves were approximated by a second-order exponential decay function, and the derived decay time constants ranged around 20-25 ns and 40-480 ns. Similar emission was observed in RL, but the decay time constants were much longer than those in PL. The RL afterglow was the lowest in the 1.0% Ce-doped sample. The 1.0% and 2.0% Ce-doped samples showed a full-energy peak in the pulse height spectrum measured underAm 5.5 MeV α-ray irradiation, and the absolute scintillation light yields were estimated to be around 55 and 36 ph/5.5 MeV-a, respectively.
文摘1 Results We have already established a methodology of supramolecular organization of porphyrin and phthalocyanine by complementary coordination of the imidazolyl substituent to their metal centers.Since the stability constants reached a range of 1011 to 1012 M-1 in nonpolar solvents,it allowed construction of stable structures such as special pair of photosynthetic reaction center and light-harvesting antenna complex of photosynthetic bacteria.Here,we report one-dimensional array of porphyrin for the d...
基金supported by the Department of Biologic and Materials Sciences,University of Michigan School of Dentistry,NSF CAREER Award (No.DMR-0845592 to KK)JSPS KAKENHI,Grant-in-Aids for Challenging Exploratory Research (No.25650053)Young Scientists (Nos.24681028 and 22700494 to KY)
文摘To gain an understanding of the toxicity of antimicrobial polymers to human cells, their hemolytic action was investigated using human red blood cells （RBCs）. We examined the hemolysis induced by cationic amphiphilic methacrylate random copolymers, which have amino ethyl sidechains as cationic units and either butyl or methyl methacpjlate as hydrophobic units. The polymer with 30 tool% butyl sidechains （B3o） displayed higher hemolytic toxicity than the polymer with 59 tool% methyl sidechains （Ms9）. B3o also induced faster release of hemoglobin from RBCs than lVlsg. A new theoretical model is proposed based on two consecutive steps to form active polymer species on the RBC membranes, which are associated to RBC lysis. This model takes the all-or-none release of hemoglobin by the rupture of RBCs into account, providing new insight into the polymer-induced hemolysis regarding how individual or collective ceils respond to the polymers.
基金Project supported by a Grant-in-Aid for Scientific Research(A)(26249147)Grant-in-Aid for Research Activity Start-up(15H06409)+3 种基金Green Photonics Research from the Ministry of Education,Culture,Sports,Science and Technology of the Japanese Government(MEXT)the Adaptable and Seamless Technology Transfer Program(A-STEP)by the Japan Science and Technology(JST)Agencythe Murata Science Foundationa Cooperative Research Project of the Research Institute of Electronics,Shizuoka University
文摘Radio-photoluminescence （RPL） is a phenomenon seen in luminescent materials in which the appearance of new photolu- minescence （PL） emission is induced by an incident ionizing radiation such as X-rays; and the signal is stable even after the irradia- tion and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in ra- diation measurements. The distinct advantage of RPL over the conventional thermally- or photo-stimulated luminescence （abbrevi- ated as TSL or PSL） dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple time without signal fading. In this work, we discovered that CsBr：Sm showed an RPL phenomenon by X-ray irradiation, and we characterized this new material as an RPL detector. While the sample showed PL emissions mainly in the visible range, after an X-ray irradiation additional emissions could be observed in the red to near-infrared range around 650-850 nm and 900-1000 nm and longer. The RPL response was fairly stable overall, but very interestingly the 650-850 nm signal slightly increased while the 900-1000 nm decreased during PL readout. The dynamic range was confirmed over 1-104 mGy with linear response.
