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Seminal characteristics and sexual behavior in men of different age groups: is there an aging effect? 被引量:10
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作者 Panayiotis M. Zavos Khalied Kaskar +1 位作者 Juan R. Correa Suresh C. Sikka 《Asian Journal of Andrology》 SCIE CAS CSCD 2006年第3期337-341,共5页
Aim: To assess the seminal characteristics as well as the sexual behavior of men of various age groups to establish the presence of an aging effect on those characteristics. Methods: Semen samples were collected fro... Aim: To assess the seminal characteristics as well as the sexual behavior of men of various age groups to establish the presence of an aging effect on those characteristics. Methods: Semen samples were collected from men (n = 792) undergoing in vitro fertilization or intrauterine insemination in cases of female factor infertility only. Samples were collected using a seminal collection device at intercourse and evaluated manually according to World Health Organization (WHO) standards. Men were divided into four groups according to their ages: (i) 20-30, (ii) 31-40, (iii) 41-50 and (iv) 51-60 years, and their seminal characteristics and responses to a sexual behavior questionnaire were compared. Results: The data showed statistically significant differences in the seminal characteristics tested, most notably in the sperm concentration, motility, grade of motility, hypo-osmotic swelling and normal sperm morphology. Furthermore, the decline in normal sperm morphology with age was more pronounced when using strict criteria rather than WHO standards. There were also differences in total sperm count, total motile sperm and total functional sperm fraction (assessed by both WHO and strict criteria). Significant differences were also observed in the sexual behavior patterns in older men in terms of the number of years they have been trying to conceive, sexual frequency and sexual satisfaction. Conclusion: The data clearly illustrate an aging effect on semen characteristics and sexual behavior in men as they age. It is suggested that the aging effect be taken into consideration when proposing normal standard values for semen characteristics in routine semen analysis as outlined by WHO standards. 展开更多
关键词 seminal parameters MALE aging effect FERTILITY sexual behavior semen quality male factor infertility
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Aging effect on the mobility and bioavailability of copper in soil 被引量:3
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作者 LU Anxiang ZHANG Shuzhen +2 位作者 QIN Xiangyang WU Wenyong LIU Honglu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第2期173-178,共6页
Aging effect on the mobility and bioavallability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworms were cultured separately in the... Aging effect on the mobility and bioavallability of copper (Cu) was investigated using a spiked soil with different incubation periods from 3 to 56 d. Wheat was planted and earthworms were cultured separately in the incubated soils. The mobility of Cu in soil was evaluated by a chemical fractionation scheme and the toxicity and bioavailability were assessed by measuring the biomass and Cu concentration in tissues. Results showed that aging had a significant effect on Cu fraction distribution, of which Cu tended to incorporate from the exchangeable into more stable fractions such as the reducible and oxidisable fractions. However, aging had little effect on Cu bioavailability to wheat and earthworm. Comparing the soil being incubated for 3 d and 56 d, Cu concentration in wheat roots decreased from 14.5 to 12.8 mg/kg, and no significant changes in Cu concentration were observed in both wheat shoots and earthworms. The Cu concentration was around 2.0 and 50 mg/kg for wheat shoots and earthworms, respectively, irrespective of soil incubation time. The CaC12-extractable Cu had a linear relationship with Cu concentration in wheat roots (R2 = 0.65, P 〈 0.05), but no linear relationship can be found for wheat shoots and earthworms. Biological control may be more crucial for Cu accumulation in organism than the changes in soil Cu fraction caused by aging. 展开更多
关键词 aging effect COPPER MOBILITY BIOAVAILABILITY
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Martensite Aging Effect and Thermal Cyclic Characteristics in Ti-Pd and Ti-Pd-Ni High Temperature Shape Memory Alloys 被引量:2
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作者 Wei Cai School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 15000k, China Kazuhiro Otsuka Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan E-mail: weicai@hope.hit.edu.cn 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第3期359-362,共4页
The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti5... The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti50Pd50-xNix (x=10, 20, 30) alloys, but no obvious thermal cycling effect was observed in Ti50Pd50Pd40Ni10 alloys and the aging effect shows a curious feature, i.e., the Af temperature does not saturate even after relatively long time aging, which is considered to be due to the occurrence of recovery recrystallization during aging. 展开更多
关键词 Ti Martensite aging effect and Thermal Cyclic Characteristics in Ti-Pd and Ti-Pd-Ni High Temperature Shape Memory Alloys PD Ni
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Vertical and horizontal displacements of a reservoir slope due to slope aging effect,rainfall,and reservoir water 被引量:1
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作者 Dongzhen Jia Ye Zhou +3 位作者 Xiufeng He Nan Xu Zhixiang Yang Minfeng Song 《Geodesy and Geodynamics》 CSCD 2021年第4期266-278,共13页
Landslides are common hazards in reservoir areas and significantly affect dam operation and human lives.For the prevention and management of landslides,accurate assessment of the factors influencing their generation i... Landslides are common hazards in reservoir areas and significantly affect dam operation and human lives.For the prevention and management of landslides,accurate assessment of the factors influencing their generation is essential.This study evaluated the key external factors influencing horizontal and vertical displacements of Luobogang Reservoir Slope in Hanyuan County,China.Displacements had been monitored by a surface-displacement-monitoring system consisting of 118 GPS stations during 2012-2015.To identify the external driving factors,their influence zones,and slope responses,we analyzed 32 months of displacement measurements and other multi-source datasets using the empirical orthogonal function.Overall,the results show that slope aging effect,rainfall,and reservoir water levels are three main driving factors.For horizontal displacement,aging effect is the most critical factor and predominantly affects the edges of landslides,the gob cave,and the public building zones.The secondary factor is the reservoir water level,which mainly acts on the boundary between the slope and reservoir water surface.The closer the slope zone is to the reservoir water,the more significant the impact is.Regarding vertical displacement,the most important factor is rainfall.The vertical displacement caused by rainfall accounts for 56.76% of the total vertical displacements.However,rainfall induces elastic displacements that generally cause less damage to the slope.The secondary factor is aging effect,and the vertical displacement caused by aging effect accounts for 9.42%.However,seven individual zones are highly affected by slope aging effect,which is consistent with the distribution of public buildings. 展开更多
关键词 Reservoir slope Horizontal and vertical displacements Influencing factors aging effect Reservoir water level
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Aging Effect on Lanthanum Doped Ferroelectric Lead Titanate Ceramics
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作者 孙大志 金雪琴 +1 位作者 朱杰 朱玉丹 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第z2期228-230,共3页
Ferroelectric devices are widely applied in many fields, such as energy conversion and communication. The aging effect in ferroelectric materials plays a central role in the reliability of the related equipments. But ... Ferroelectric devices are widely applied in many fields, such as energy conversion and communication. The aging effect in ferroelectric materials plays a central role in the reliability of the related equipments. But it is very difficult to understand the origin of aging effect in ferroelectrics because these materials possess different defects and exhibit various aging behavior. The reverse transition temperature in lead titanate doped with lanthanum increases during aging at ferroelectric phase was reported. It is well known that lattice defects, such as vacancies and solute atoms, are ubiquitous in crystalline solids. These point defects affect physical properties in ferroelectrics significantly. The abnormal increase of the reverse transition temperature was discussed in terms of diffusion of point defects during aging. Dielectric performance in the material after aging was measured and discussed as well. 展开更多
关键词 aging effect FERROELECTRIC reverse transformation temperature (Pb La)TiO3 rare earths
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Seminal characteristics and sexual behavior in men of different age groups:is there an aging effect?
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作者 PanayiotisM.Zavos KhaliedKaskar +1 位作者 Juan R.Correa Suresh C.Sikka 《Asian Journal of Andrology》 SCIE CAS CSCD 2006年第A03期337-341,388,共5页
Aim:To assess the seminal characteristics as well as the sexual behavior of men of various age groups to establish the presence of an aging effect on those characteristics.Methods:Semen samples were collected from men... Aim:To assess the seminal characteristics as well as the sexual behavior of men of various age groups to establish the presence of an aging effect on those characteristics.Methods:Semen samples were collected from men(n=792) undergoing in vitro fertilization or intrauterine insemination in cases of female factor infertility only.Samples were collected using a seminal collection device at intercourse and evaluated manually according to World Health Organiza- tion(WHO)standards.Men were divided into four groups according to their ages:(i)20-30,(ii)31-40,(iii)41-50 and(iv)51-60 years,and their seminal characteristics and responses to a sexual behavior questionnaire were compared. Results:The data showed statistically significant differences in the seminal characteristics tested,most notably in the sperm concentration,motility,grade of motility,hypo-osmotic swelling and normal sperm morphology.Furthermore, the decline in normal sperm morphology with age was more pronounced when rising strict criteria rather than WHO standards.There were also differences in total sperm count,total motile sperm and total functional sperm fiaction (assessed by both WHO and strict criteria).Significant differences were also observed in the sexual behavior patterns in older men in terms of the number of years they have been trying to conceive,sexual flequency and sexual satisfaction. Conclusion:The data clearly illustrate an aging effect on semen characteristics and sexual behavior in men as they age.It is suggested that the aging effect be taken into consideration when proposing normal standard values for semen characteristics in routine semen analysis as outlined by WHO standards. 展开更多
关键词 seminal parameters MALE aging effect FERTILITY sexual behavior semen quality male factor infertility
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Effects of aging treatment on the microstructure and superelasticity of columnar-grained Cu71Al18Mn11 shape memory alloy 被引量:3
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作者 Ji-li Liu Hai-you Huang Jian-xin Xie 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第10期1157-1166,共10页
The effect of aging treatment on the superelasticity and martensitic transformation critical stress in columnar-grained Cu_(71)Al_(18)Mn_(11) shape memory alloy(SMA) at the temperature ranging from 250°C ... The effect of aging treatment on the superelasticity and martensitic transformation critical stress in columnar-grained Cu_(71)Al_(18)Mn_(11) shape memory alloy(SMA) at the temperature ranging from 250°C to 400°C was investigated. The microstructure evolution during the aging treatment was characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results show that the plate-like bainite precipitates distribute homogeneously within austenitic grains and at grain boundaries. The volume fraction of bainite increases with the increase in aging temperature and aging time, which substantially improves the martensitic transformation critical stress of the alloy, whereas the bainite only slightly affects the superelasticity. This behavior is attributed to a coherent relationship between the bainite and the austenite, as well as to the bainite and the martensite exhibiting the same crystal structure. The variations of the martensitic transformation critical stress and the superelasticity of columnar-grained Cu_(71)Al_(18)Mn_(11) SMA with aging-temperature and aging time are described by the Austin-Rickett equation, where the activation energy of bainite precipitation is 77.2 kJ ·mol1. Finally, a columnar-grained Cu_(71)Al_(18)Mn_(11) SMA with both excellent superelasticity(5%-9%) and high martensitic transformation critical stress(443-677 MPa) is obtained through the application of the appropriate aging treatments. 展开更多
关键词 copper aluminum manganese alloys shape memory effect columnar grains aging bainite superelasticity
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The Effects of Dietary Restriction and Aging on in Vivo and in Vitro Binding of Aflatoxin B_1 to Cellular DNA
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作者 MING W.CHOU REX A.PEGRAM +3 位作者 PU GAO S.R.HANSARD J.G.SHADDOCK D.A.CASCIANO 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1991年第1期134-143,共10页
Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum- fed counterparts... Laboratory animals maintained on a reduced calorie but nutritionally adequate diet have extended life spans and lowered incidences of spontaneous and chemically induced cancers compared to ad libitum- fed counterparts. Many of the effects of dietary restriction on laboratory animals have been suggested to be related to a deceleration of the aging process. The inhibition of age-related changes in xenobiotic metabolizing enzyme activities by dietary restriction has previously been reported. Alterations of these enzyme activities may cause changes in metabolic activation of carcinogens and, therefore, carcinogen-DNA binding. DNA-repair capability has also been reported to be enhanced in diet-restricted rats. Using AFB1 as a model carcinogen, we have studied in vivo and in vitro hepatic AFB1 -DNA binding, demonstrating that dietary restriction (60% of ad libitum consumption) may decrease the metabolic activation of AFB1, and subsequently reduce AFB 1-DNA binding. Our preliminary results obtained from the AFB 1-DNA binding experiments in isolated hepatocytes suggest that the observed age-dependent reduction in AFB 1-DNA binding which may be attributed to a loss of metabolic activating capability was delayed in the diet-restricted rats. 展开更多
关键词 The effects of Dietary Restriction and aging on in Vivo and in Vitro Binding of Aflatoxin B1 to Cellular DNA AFB
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Long-Term Animal Feeding Trial of the Refined Konjac Meal Ⅱ. Effects of the Refined Konjac Meal on the Aging of the Brain, Liver, and Cardiovascular Tissue Cells in Rats
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作者 PENG SHU-SHENG ZHANG MAO-YU +1 位作者 ZHANG YIN-ZU AND WU ZI-HUA(School of Public Health, West China University of Medical Sciences,Chengdu 610041, China) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1995年第1期80-87,共8页
Rats of both sexes were fed on a basal feed containing 1% refined konjac meal (RKM) for 18 months and the effects of RKM on the cell aging were observed. A comparable group fed on the basic feed was used as the contro... Rats of both sexes were fed on a basal feed containing 1% refined konjac meal (RKM) for 18 months and the effects of RKM on the cell aging were observed. A comparable group fed on the basic feed was used as the control. Results obtained demonstrate that the long-term feeding of RKM to rats can delay the course of cell aging of the gliocyte, cadiomyocyte, and the endothelial cell of the large and medium arteriases, hence it is likely to delay the occurrence of arteriosclerosis and improve the functions of the brain, heart and vascular system. 展开更多
关键词 and Cardiovascular Tissue Cells in Rats Liver effects of the Refined Konjac Meal on the aging of the Brain Long-Term Animal Feeding Trial of the Refined Konjac Meal
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Research progress on aging of organic pollutants in geosorbents:a review 被引量:2
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作者 Xianjin An Baohua xiao +2 位作者 Xinyue Di Hui Dong Haiming Tang 《Acta Geochimica》 EI CAS CSCD 2017年第1期27-43,共17页
Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natu... Geosorbents are the main host of anthropogenic organic pollutants and play a vital role in their fate and transport in the natural environment.Soil and sediment are the most common and abundant geosorbents in the natural environment;their interactions with organic pollutants,especially sorption and desorption processes,have been extensively studied from the perspectives of thermodynamics and kinetics.Recently,the aging of organic pollutants in geosorbents has drawn increased attention,leading to an improved understanding of interactions between organic pollutants and geosorbents and informing remediation criteria.Aging has been deemed important in accurately assessing ecologic and health risks of organic pollutants,and both positive and negative impacts have been reported in studies of natural and artificial sorbents.This paper summarizes recent research progress on organic pollutant aging in geosorbents,including related mechanism research,influence factors,bioavailability assessments,and biological and physicochemical remediation of aged organic pollutants.We also discuss issues in the current research and bring forward suggestions for future study. 展开更多
关键词 Geosorbent aging effects BIOAVAILABILITY Organic pollutants Supergene processes
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Stress-state dependence of dynamic strain aging:Thermal hardening and blue brittleness 被引量:1
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作者 Wen-qi Liu Jun-he Lian 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第5期854-866,共13页
This study aims to discover the stress-state dependence of the dynamic strain aging(DSA)effect on the deformation and fracture behavior of high-strength dual-phase(DP)steel at different deformation temperatures(25-400... This study aims to discover the stress-state dependence of the dynamic strain aging(DSA)effect on the deformation and fracture behavior of high-strength dual-phase(DP)steel at different deformation temperatures(25-400°C)and reveal the damage mechanisms under these various configurations.To achieve different stress states,predesigned specimens with different geometric features were used.Scanning electron microscopy was applied to analyze the fracture modes(e.g.,dimple or shear mode)and underlying damage mechanism of the investigated material.DSA is present in this DP steel,showing the Portevin-Le Chatelier(PLC)effect with serrated flow behavior,thermal hardening,and blue brittleness phenomena.Results show that the stress state contributes distinctly to the DSA effect in terms of the magnitude of thermal hardening and the pattern of blue brittleness.Either low stress triaxiality or Lode angle parameter promotes DSA-induced blue brittleness.Accordingly,the damage mechanisms also show dependence on the stress states in conjunction with the DSA effect. 展开更多
关键词 dynamic strain aging effect Portevin-Le Chatelier effect damage mechanism dimple fracture shear fracture dual-phase steel
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Hygrothermal effect on high-velocity impact resistance of woven composites 被引量:1
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作者 Xiao-chen Yang Nan Jia 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第5期823-833,共11页
The woven glass fiber reinforced composites(GFRP)subjected to high-speed impact is investigated to identify the hygrothermal aging effect on the impact resistance.Both the hygrothermal aged and unaged glass/epoxy lami... The woven glass fiber reinforced composites(GFRP)subjected to high-speed impact is investigated to identify the hygrothermal aging effect on the impact resistance.Both the hygrothermal aged and unaged glass/epoxy laminates are subjected to different impact velocities,which is confirmed as a sensitive factor for the failure modes and mechanisms.The results show the hygrothermal aging effect decreases the ballistic limit by 14.9%,but the influence on ballistic performance is limited within the impact velocity closed to the ballistic limit.The failure modes and energy dissipation mechanisms are confirmed to be slightly influenced by the hygrothermal aging effect.The hygrothermal aging effect induced localization of structural deformation and degradation of mechanical properties are the main reasons for the composite undergoing the same failure modes at smaller impact velocities.Based on the energy absorption mechanisms,analytical expressions predict the ballistic limit and energy absorption to reasonable accuracy,the underestimated total energy absorption results in a relatively poor agreement between the measured and predicted energy absorption efficiency. 展开更多
关键词 Hygrothermal aging effect Woven glass/epoxy composite Impact resistance Dynamic failure Energy absorption
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Ageing Effect on Hardness and Microstructure of Al-Zn-Mg Alloys 被引量:5
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作者 M.Iqbal, M.A.Shaikh, M.Ahmad and K.A.Shoaib (Nuclear Physics Division, Pakistan Institute of Nuclear Science and Technology P.O.Nilore, Islamabad, Pakistan) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第3期319-322,共4页
Experimental results of the investigation on the hardness of two Al-Zn-Mg alloys [Al-10.0 Zn-4.0 Mg and Al-8.5 Zn-3.0 Mg (wt pct)] aged in the temperature range 60~310℃ for different intervals of time from 1/4 h to ... Experimental results of the investigation on the hardness of two Al-Zn-Mg alloys [Al-10.0 Zn-4.0 Mg and Al-8.5 Zn-3.0 Mg (wt pct)] aged in the temperature range 60~310℃ for different intervals of time from 1/4 h to 168 h are presented. Both the alloys were found to show identical behaviour of hardness with ageing time. Alloy with higher Zn and Mg content had higher hardness than the alloy with lower solute content. There were three ranges of temperature in which different types of precipitates formed and affected the hardness. Some of the grain boundaries were found to migrate and precipitate free zone has been observed. 展开更多
关键词 ZN Ageing effect on Hardness and Microstructure of Al-Zn-Mg Alloys AL
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Coercivity Ageing Effect on FePt Nanoparticles in Mesoporous Silica via Stepwise Synthesis Strategy
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作者 Tian-Le Wang Zhi-Gang Li +3 位作者 Li Zhang Wei-Ping Chen Shang-Shen Feng Wen-Wu Zhong 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期94-97,共4页
FePt nanoparticles in mesoporous silica are fabricated by a simple stepwise synthesis strategy.A pre-annealing temperature-dependent coercivity-ageing effect in FePt nanoparticles is observed at room temperature.For f... FePt nanoparticles in mesoporous silica are fabricated by a simple stepwise synthesis strategy.A pre-annealing temperature-dependent coercivity-ageing effect in FePt nanoparticles is observed at room temperature.For facecentered cubic(fcc)structured FePt nanoparticles,the ageing effect is sensitive to the pre-annealing temperature,especially when the temperature is close to the phase-transition.The special magnetic behavior of FePt nanoparticles reveals that the physical properties gradually change between fee and face-centered tetragonal structures,and will deepen our understanding of the mechanism of such magnetism in FePt nanoparticles. 展开更多
关键词 Coercivity Ageing effect on FePt Nanoparticles in Mesoporous Silica via Stepwise Synthesis Strategy
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Suppressing Effects of Ag Wetting Layer on Surface Conduction of Er Silicide/Si(001) Nanocontacts
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作者 Qing Han Qun Cai 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第8期74-78,共5页
Current-voltage electrical characteristics of Er silicide/Si(001) nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on... Current-voltage electrical characteristics of Er silicide/Si(001) nanocontacts are measured in situ in a scanning tunneling microscopy system. Introduced as a new technique to suppress surface leakage conduction on Si(001),a silver wetting layer is evaporated onto the substrate surface kept at room temperature with Er Si2 nanoislands already existing. The effects of the silver layer on the current-voltage characteristics of nanocontacts are discussed.Our experimental results reveal that the silver layer at coverage of 0.4–0.7 monolayer can suppress effectively the current contribution from the surface conduction path. After the surface leakage path of nanocontacts is obstructed, the ideality factor and the Schottky barrier height are determined using the thermionic emission theory, about 2 and 0.5 eV, respectively. The approach adopted here could shed light on the intrinsic transport properties of metal-semiconductor nanocontacts. 展开更多
关键词 AG Suppressing effects of Ag Wetting Layer on Surface Conduction of Er Silicide/Si NANOCONTACTS
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Doping Effect of Co at Ag Sites in Antiperovskite Mn3AgN Compounds
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作者 褚立华 王聪 +5 位作者 孙莹 李美成 万子裴 王宇 窦尚轶 楚月 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第4期126-129,共4页
Antiperovskite compounds Mn3Ag1-xCoxN (x =0.2, 0.5 and 0.8) are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction o... Antiperovskite compounds Mn3Ag1-xCoxN (x =0.2, 0.5 and 0.8) are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction of Co. However, with the increase of the content of Co, the spin reorientation gradually disappears and the antiferromagnetic transition changes to the ferromagnetic transition at the elevated temperature when x = 0.8. In addition, all of the magnetic phase transitions at the elevated temperature are always accompanied by the abnormal thermal expansion behaviors and an entropy change. Moreover, when x = 0.8, the coefficient of linear expansion is -1.89 × 10^-6 K^-1 (290-310K, △T =20 K), which is generally considered as the low thermal expansion. 展开更多
关键词 AG CO Doping effect of Co at Ag Sites in Antiperovskite Mn3AgN Compounds MN
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Effect of Accelerated Ageing on the Dielectric Behaviour of Some Varnish Dry Films
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作者 S.A.El-Henawii(Faculty of Science, Helwan University, Cairo, Egypt) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1995年第5期323-328,共6页
The variation of the dielectric constant e' and the dielectric loss e' of polyesteramide, alkyd polyesteramide and alkyd varnish dry films were measured within the frequency range from 105 to 107 Hz and the te... The variation of the dielectric constant e' and the dielectric loss e' of polyesteramide, alkyd polyesteramide and alkyd varnish dry films were measured within the frequency range from 105 to 107 Hz and the temperature range from 20 to 50℃. The varnish films were subjected to accelerated ageing by heating at 110℃ for diferent durations. The efect of the accelerated ageing on e' and e' were measured. The activation energy and the entropy change of dielectric relaxation for the dry films before and after ageing were also calculated. All the results obtained were recorded and discussed in correlation with the molecular structure of the investigated varnishes. 展开更多
关键词 effect of Accelerated Ageing on the Dielectric Behaviour of Some Varnish Dry Films
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基于介质阻挡大气压空气均匀放电的聚丙稀薄等离子体表面处理(英文) 被引量:6
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作者 方志 蔡玲玲 +2 位作者 雷枭 邱毓昌 Kuffel Edmund 《高电压技术》 EI CAS CSCD 北大核心 2011年第11期2746-2751,共6页
The homogeneous dielectric barrier discharge(DBD) in atmospheric air is most favorable for polymer surface modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing... The homogeneous dielectric barrier discharge(DBD) in atmospheric air is most favorable for polymer surface modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing.In this paper,polypropylene(PP) films are treated using a homogeneous DBD plasma in atmospheric air.The surface properties of PP films are studied using contact angle and surface energy measurement,scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy(FTIR),and the aging effect after treatment when the treated materials are exposed to open air is also studied,with the modification mechanism being discussed.It is demonstrated that non-thermal plasmas generated by homogeneous DBD in atmospheric air is an effective way to enhance the surface properties of PP films.After the plasma treatment,the surface of PP film is etched,and oxygen-containing polar groups are introduced into the surface.These two processes can induce a remarkable decrease in water contact angle and a remarkable increase in surface energy,and the surface properties of PP films are improved accordingly. 展开更多
关键词 dielectric barrier discharge(DBD) homogeneous discharge surface modification polypropylene(PP)films HYDROPHILICITY aging effect
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Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation 被引量:7
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作者 Zhou Yanguo Sun Zhengbo +2 位作者 Chen Jie Chen Yunmin Chen Renpeng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2017年第2期247-261,共15页
The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the w... The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity (V)-void ratio (e) of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V of soil is raised high enough (i.e., no less than the critical velocity) to resist the given earthquake loading according to the CRR-V relationship, and then this requirement is transferred to the control of target void ratio (i.e., the critical e) according to the V-e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes. 展开更多
关键词 Liquefaction mitigation Stone column Shear wave velocity Void ratio DENSIFICATION Ageing effect
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Surface modification of polytetrafluoroethylene film using single liquid electrode atmospheric-pressure glow discharge 被引量:1
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作者 周澜 吕国华 +3 位作者 陈维 庞华 张谷令 杨思泽 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第6期329-335,共7页
Polytetrafluoroethylene films are treated by room temperature helium atmospheric pressure plasma plumes, which are generated with a home-made single liquid electrode plasma device. After plasma treatment, the water co... Polytetrafluoroethylene films are treated by room temperature helium atmospheric pressure plasma plumes, which are generated with a home-made single liquid electrode plasma device. After plasma treatment, the water contact angle of polytetrafiuoroethylene fihn drops from 114° to 46° and the surface free energy increases from 22.0 mJ/m2 to 59.1 mJ/m2. The optical emission spectrum indicates that there are reactive species such as O2+, O and He in the plasma plume. After plasma treatment, a highly crosslinking structure is formed on the fihn surface and the oxygen element is incorporated into the film surface in the forms of C O-C-, -C=O, and O C=O groups. Over a period of 10 days, the contact angle of the treated film is recovered by only about 10°, which indicates that the plasma surface modification is stable with time. 展开更多
关键词 single liquid electrode atmospheric pressure glow discharge WETTABILITY ageing effect
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