Martensitic-based microstructures in low-density steels offer high strength and improved specific strength,combined with the lightweight effect of aluminum(Al).However,while Al effectively reduces density,it simultane...Martensitic-based microstructures in low-density steels offer high strength and improved specific strength,combined with the lightweight effect of aluminum(Al).However,while Al effectively reduces density,it simultaneously promotes the formation of coarse ferrite and expands the two-phase(α+γ)intercritical temperature range.Thus,increasing the Al content for higher weight reduction inevitably leads to ferrite formation and impedes further strengthening.To achieve both high strength and duc-tility while incorporating ferrite,it is crucial to elucidate the effects of ferrite fraction,size,and dis-tribution on mechanical properties and deformation behavior,particularly in relation to phase interac-tions.In this study,three model steels were developed through controlled annealing temperatures,pro-ducing distinct triplex microstructures comprising ferrite,martensite,and retained austenite(RA).The role of each phase in strain partitioning was investigated using ex-situ microscopic digital image cor-relation and electron back-scattered diffraction analysis.Key findings reveal that the martensitic matrix ensures an ultrahigh strength level(1758 MPa),while a moderate fraction(∼17%)and homogeneous dis-tribution of intercritical-ferrite(IC-ferrite)enable sustainable strain-hardening behavior by delaying the transformation-induced plasticity(TRIP)effect.Strain partitioning into IC-ferrite reduces local strains in the martensitic matrix,preventing early exhaustion of the TRIP effect and facilitating ductile fracture behavior.This strategy leverages the presence of ferrite,offering significant advantages for applications requiring both ultrahigh strength and ductility.展开更多
Aim: To evaluate the sperm motility stimulating activity of a sulfono glycolipid (S-ACT-1) isolated from Gelidiellaacerosa, a Sfi Lankan marine red algae. Methods: S-ACT-I, a white amorphous powder was separated from ...Aim: To evaluate the sperm motility stimulating activity of a sulfono glycolipid (S-ACT-1) isolated from Gelidiellaacerosa, a Sfi Lankan marine red algae. Methods: S-ACT-I, a white amorphous powder was separated from morepolar fractions of the hexane soluble of 1:1 CH_2Cl_2/MeOH extract and subjected to ~1H, ^(13)C NMR and IR Spectroscopyafter reverse phase HPLC for identification. Effects of S-ACT-1 on human sperm motility was assessed in vitro at 10,100 and 1000μg/mL concentrations at 37℃ for 0, 5, 15, 30 and 60 min. Results: S-ACT-1 was identified as aglycolipid sulfate. The lower dose increased the sperm motility slightly, whilst the medium dose significantly increasedthe motility (P < 0.05) from 5 min of incubation reaching a peak at 15 min and the stimulant effect was sustainedthroughout the experimental period. Furthermore, the medium dose rendered 80% of the immotile viable sperm motile.In contrast, the highest dose impaired the sperm motility. The sperm stimulating activity of S-ACT-1 was dose-depen-dent and had a bell-shaped dose response curve for all the 5 incubation periods. Conclusion: S-ACT-1 of Gelidiellaacerosa is a Sulfono glycolipid. S-ACT-1 has a potent sperm motility stimulating activity in vitro and has the potentialto be developed into a sperm stimulant. (Asian J Androl 2001 Mar; 3: 27-31)展开更多
A 16-bit 170 MS/s pipelined ADC implemented in 0.18 m CMOS process is presented in this paper. An improved digital calibration method and a linearized sampling front-end are employed to achieve a high SFDR. The enlarg...A 16-bit 170 MS/s pipelined ADC implemented in 0.18 m CMOS process is presented in this paper. An improved digital calibration method and a linearized sampling front-end are employed to achieve a high SFDR. The enlarged full scale range makes it possible to obtain a high SNR with smaller sampling capacitors, thus achieving higher speed and low power. This ADC attains an SNR of 77.2 d BFS, an SFDR of 97.6 d Bc for a 10 MHz input signal, while preserving an SFDR 〉 80 d Bc up to 300 MHz input frequency. The ADC consumes 430 mW from a1.8 V supply and occupies a 17 mm^2 active area.展开更多
基金financially supported by Korea Institute for Advancement of Technology(KIAT)grant funded by the Ko-rea Government(MOTIE)(HRD Program for Industrial Innova-tion)(P0023676)the National Research Foundation of Ko-rea(NRF)grant funded by the Korea government(MSIT)(NRF-2022R1A5A1030054,RS-2023-00281508,NRF-RS-2024-00345498).
文摘Martensitic-based microstructures in low-density steels offer high strength and improved specific strength,combined with the lightweight effect of aluminum(Al).However,while Al effectively reduces density,it simultaneously promotes the formation of coarse ferrite and expands the two-phase(α+γ)intercritical temperature range.Thus,increasing the Al content for higher weight reduction inevitably leads to ferrite formation and impedes further strengthening.To achieve both high strength and duc-tility while incorporating ferrite,it is crucial to elucidate the effects of ferrite fraction,size,and dis-tribution on mechanical properties and deformation behavior,particularly in relation to phase interac-tions.In this study,three model steels were developed through controlled annealing temperatures,pro-ducing distinct triplex microstructures comprising ferrite,martensite,and retained austenite(RA).The role of each phase in strain partitioning was investigated using ex-situ microscopic digital image cor-relation and electron back-scattered diffraction analysis.Key findings reveal that the martensitic matrix ensures an ultrahigh strength level(1758 MPa),while a moderate fraction(∼17%)and homogeneous dis-tribution of intercritical-ferrite(IC-ferrite)enable sustainable strain-hardening behavior by delaying the transformation-induced plasticity(TRIP)effect.Strain partitioning into IC-ferrite reduces local strains in the martensitic matrix,preventing early exhaustion of the TRIP effect and facilitating ductile fracture behavior.This strategy leverages the presence of ferrite,offering significant advantages for applications requiring both ultrahigh strength and ductility.
文摘Aim: To evaluate the sperm motility stimulating activity of a sulfono glycolipid (S-ACT-1) isolated from Gelidiellaacerosa, a Sfi Lankan marine red algae. Methods: S-ACT-I, a white amorphous powder was separated from morepolar fractions of the hexane soluble of 1:1 CH_2Cl_2/MeOH extract and subjected to ~1H, ^(13)C NMR and IR Spectroscopyafter reverse phase HPLC for identification. Effects of S-ACT-1 on human sperm motility was assessed in vitro at 10,100 and 1000μg/mL concentrations at 37℃ for 0, 5, 15, 30 and 60 min. Results: S-ACT-1 was identified as aglycolipid sulfate. The lower dose increased the sperm motility slightly, whilst the medium dose significantly increasedthe motility (P < 0.05) from 5 min of incubation reaching a peak at 15 min and the stimulant effect was sustainedthroughout the experimental period. Furthermore, the medium dose rendered 80% of the immotile viable sperm motile.In contrast, the highest dose impaired the sperm motility. The sperm stimulating activity of S-ACT-1 was dose-depen-dent and had a bell-shaped dose response curve for all the 5 incubation periods. Conclusion: S-ACT-1 of Gelidiellaacerosa is a Sulfono glycolipid. S-ACT-1 has a potent sperm motility stimulating activity in vitro and has the potentialto be developed into a sperm stimulant. (Asian J Androl 2001 Mar; 3: 27-31)
基金Project supported by the National Science and Technology Major Project(No.2009ZX01034-002-001-016)
文摘A 16-bit 170 MS/s pipelined ADC implemented in 0.18 m CMOS process is presented in this paper. An improved digital calibration method and a linearized sampling front-end are employed to achieve a high SFDR. The enlarged full scale range makes it possible to obtain a high SNR with smaller sampling capacitors, thus achieving higher speed and low power. This ADC attains an SNR of 77.2 d BFS, an SFDR of 97.6 d Bc for a 10 MHz input signal, while preserving an SFDR 〉 80 d Bc up to 300 MHz input frequency. The ADC consumes 430 mW from a1.8 V supply and occupies a 17 mm^2 active area.
