Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual 'W'-shaped galvanic cell whose cathode is the grain boundary oxide film (G...Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual 'W'-shaped galvanic cell whose cathode is the grain boundary oxide film (G.B.0. film) and surface film and the anode is fresh metal at the cracked tip on both sides of the G.B.0. film. Redox reactions involved in the cell have been proposed here. According to this mdel, initidtion of ISCC is caused by the rupturing of surface film along grain boundaries, thus forming a galvanic cell. Propagation of ISCC resulted from alternate advances of G.B.0. film and dissolution on both sides of G.B.0. film caused by the effect of electrochemical reaction. This work developed an effective approach to investigate the embrittlement process at the tip of the crack, by increasing the length of the embrittlement region through constant strain test and distinguishing the morphology and the nature of the corrosion products by optical microscopy and scanning electron microscopy (SEH).展开更多
This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied an...This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied and it was acceptable. The spatial resolution of the z-direction has much room for improvement by increasing the number of cameras. When applied to the velocity distribution measurement of a thermal vertical buoyant plume, the proposed 3D PIV method is found to be very effective for studying thermal structures and well suited for measuring the airflow velocity field.展开更多
When an oceanographic vessel is sailing, the currents near the surface of ship hull are rapid, making it hard to meet the environmental requirements of scientific observation equipment. To guarantee the installation s...When an oceanographic vessel is sailing, the currents near the surface of ship hull are rapid, making it hard to meet the environmental requirements of scientific observation equipment. To guarantee the installation space and environmental requirements of the observation equipment, the drop keel system was proposed for the first time for ocean-graphic ships at China, to avoid the traditional ＂rudder-shaft＂ type fin keel＇s disadvantage. The research study will examine the operational mechanism and functions of the drop keel system, the operating conditions of the fin keel to determine the driver method and its arrangement, and the locking method of the fin keel underwater. The research wilI also provide some general designs for analyzing the best plan for the drop keel system.展开更多
With the diminishing Arctic sea ice,the dynamic energy-exchange process between sea ice and ocean gains in importance.Concerning how the ice bottom topography affects the drift of sea ice,it is unclear how the ridge k...With the diminishing Arctic sea ice,the dynamic energy-exchange process between sea ice and ocean gains in importance.Concerning how the ice bottom topography affects the drift of sea ice,it is unclear how the ridge keel-drag force exerted by seawater changes the momentum balance of sea ice.We thus conducted laboratory experiments to investigate how the local drag coefficient of the ridge keel depends on keel shape and on the relative velocity of ice with respect to seawater.A dimensional analysis is used to obtain the relationship between the local drag coefficient Cr,the Reynolds number Re,the dimensionless keel depth h0,and the keel slope angleφ.The results indicate that the local drag coefficient Cr is only relevant to Re when Re<4000 and the flow is in the laminar regime.With increasing Re,Cr depends on h0 andφ,which are independent variables,as the flow transitions to the turbulent regime.The parameterization formulas for Cr are also provided.展开更多
A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an i...A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an ice keel in the Arctic Ocean.During the interaction process,the internal surge was generated at first,and then the wave gradually steepened due to non-linearity during its propagation away from the ice keel.The internal surge eventually disintegrated into multi-modal and rank-ordered ISW packets with the largest having an amplitude of O(10)m.Sensitivity experiments demonstrated that the ISWs’amplitudes and energy were proportional to the varying ice keel depths and barotropic tidal fl ow amplitudes,but were insensitive to the changing ice keel widths.Typical ISWs can enhance the turbulent dissipation rate of O(10^(-6))W/kg along their propagation path.Further,heat entrainment induced by the wave-ice interaction can reach O(10)MJ/m per tidal cycle.This study reveals a particular ISW generation mechanism and process in the polar ice environment,which could be important in impacting the energy transfer and heat balance in the Arctic Ocean.展开更多
This paper outlines a curriculum model for contemporary programme design for the purpose of embedding educational innovation and technology within an inter-professional nursing curriculum. It has been developed from w...This paper outlines a curriculum model for contemporary programme design for the purpose of embedding educational innovation and technology within an inter-professional nursing curriculum. It has been developed from work within the School of Nursing and Midwifery at Keele University during the re-write of both the nursing and midwifery curriculum. The Nursing and Midwifery Council (NMC) require approval of all recordable programmes every five years and as such the school took this review as an opportunity to explore the curriculum model currently in use and develop an approach that would facilitate the professional requirements of the programme alongside the embedding of innovative learning and teaching methodologies. The model springs from extensive application of contemporary pedagogy underpinning adult learning, and forces consideration of cognitive alignment within a multi-modal delivery framework [1]. The model builds upon the early work of Fowler and Mayes [2] and later work of Bird [3] who explored the antecedents and underpinning theory for success within online learning experiences. This model has greater reach;having strategic fit for acontemporary “technology enhanced learning” application within further and higher education [4], whilst ensuring the achievement of given professional standards [5].展开更多
【目的】龙骨骨折(keel bone fracture, KBF)已成为影响蛋鸡健康和生产的重要福利问题。试验旨在评估产蛋期龙骨骨折的发生与否对产蛋后期的蛋鸡恐惧行为、生产性能和蛋品质的影响。【方法】选取60周龄的海兰褐蛋鸡和林甸鸡各100只,单...【目的】龙骨骨折(keel bone fracture, KBF)已成为影响蛋鸡健康和生产的重要福利问题。试验旨在评估产蛋期龙骨骨折的发生与否对产蛋后期的蛋鸡恐惧行为、生产性能和蛋品质的影响。【方法】选取60周龄的海兰褐蛋鸡和林甸鸡各100只,单笼饲养于传统叠层式鸡笼。利用触诊和便携式X光仪区分龙骨骨折蛋鸡和未骨折蛋鸡,通过紧张不动性测试(TI)、旷场试验(OFT)和惊吓反射试验(SRT)依次测量恐惧行为反应,并测定68周龄时蛋鸡的生产性能和蛋品质。【结果】在TI试验中,2个品种龙骨骨折蛋鸡的紧张不动时长显著高于正常蛋鸡(P<0.05)。在OFT试验中,龙骨骨折的海兰褐蛋鸡和林甸鸡在穿过的格子数、步数和在外圈停留的时间均显著低于正常蛋鸡(P<0.05),在内圈停留的时间显著高于正常蛋鸡(P<0.05),且骨折的海兰褐蛋鸡的运动潜伏期显著高于正常蛋鸡(P<0.05)。在SRT试验中,龙骨骨折蛋鸡惊吓反射总得分显著低于正常蛋鸡(P<0.05)。因此,龙骨骨折蛋鸡的恐惧行为反应较强烈。2个品种龙骨骨折蛋鸡的产蛋率显著低于正常蛋鸡(P<0.05),且骨折的海兰褐蛋鸡蛋形指数低于正常蛋鸡(P<0.05),其余蛋品质参数在骨折蛋鸡和正常蛋鸡中无显著性差异(P>0.05)。【结论】龙骨骨折加剧了蛋鸡的恐惧行为反应,降低了产蛋后期蛋鸡的福利水平和生产性能。展开更多
文摘Intergranular stress corrosion cracking (ISCC) of α-brass in neutral Mattsson's solution was found to be controlled by an unusual 'W'-shaped galvanic cell whose cathode is the grain boundary oxide film (G.B.0. film) and surface film and the anode is fresh metal at the cracked tip on both sides of the G.B.0. film. Redox reactions involved in the cell have been proposed here. According to this mdel, initidtion of ISCC is caused by the rupturing of surface film along grain boundaries, thus forming a galvanic cell. Propagation of ISCC resulted from alternate advances of G.B.0. film and dissolution on both sides of G.B.0. film caused by the effect of electrochemical reaction. This work developed an effective approach to investigate the embrittlement process at the tip of the crack, by increasing the length of the embrittlement region through constant strain test and distinguishing the morphology and the nature of the corrosion products by optical microscopy and scanning electron microscopy (SEH).
文摘This study proposes a three-dimensional (3D) particle image velocimetry (PIV) method using W- shaped light sheet and color PIV with a digital SLR camera. The uncertainty of the velocity measurement was also studied and it was acceptable. The spatial resolution of the z-direction has much room for improvement by increasing the number of cameras. When applied to the velocity distribution measurement of a thermal vertical buoyant plume, the proposed 3D PIV method is found to be very effective for studying thermal structures and well suited for measuring the airflow velocity field.
文摘When an oceanographic vessel is sailing, the currents near the surface of ship hull are rapid, making it hard to meet the environmental requirements of scientific observation equipment. To guarantee the installation space and environmental requirements of the observation equipment, the drop keel system was proposed for the first time for ocean-graphic ships at China, to avoid the traditional ＂rudder-shaft＂ type fin keel＇s disadvantage. The research study will examine the operational mechanism and functions of the drop keel system, the operating conditions of the fin keel to determine the driver method and its arrangement, and the locking method of the fin keel underwater. The research wilI also provide some general designs for analyzing the best plan for the drop keel system.
基金This research was supported by the National Key R&D Program of China(Grant no.2017YFE0111400)National Natural Science Foundation of China(Grant nos.41922045 and 41876213)the Fundamental Research Funds for the Central Universities.
文摘With the diminishing Arctic sea ice,the dynamic energy-exchange process between sea ice and ocean gains in importance.Concerning how the ice bottom topography affects the drift of sea ice,it is unclear how the ridge keel-drag force exerted by seawater changes the momentum balance of sea ice.We thus conducted laboratory experiments to investigate how the local drag coefficient of the ridge keel depends on keel shape and on the relative velocity of ice with respect to seawater.A dimensional analysis is used to obtain the relationship between the local drag coefficient Cr,the Reynolds number Re,the dimensionless keel depth h0,and the keel slope angleφ.The results indicate that the local drag coefficient Cr is only relevant to Re when Re<4000 and the flow is in the laminar regime.With increasing Re,Cr depends on h0 andφ,which are independent variables,as the flow transitions to the turbulent regime.The parameterization formulas for Cr are also provided.
基金Supported by the National Key Research and Development Program of China and National Natural Science Foundation of China(Nos.2019YFE0105700,2016YFC1402705,2017YFA0604102,92058202,91858103,42176244,2016YFC1401404)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA22050202,XDB42000000)+1 种基金the CAS Key Research Program of Frontier Sciences and Key Deployment Project of Centre for Ocean Mega-Research of Science(Nos.QYZDB-SSW-DQC024,COMS2020Q07)the project jointly funded by the CAS and CSIRO(No.133244KYSB20190031)。
文摘A series of non-hydrostatic,non-linear numerical simulations were carried out to investigate the generation and evolution of internal solitary waves(ISWs)through the interaction of a barotropic tidal current with an ice keel in the Arctic Ocean.During the interaction process,the internal surge was generated at first,and then the wave gradually steepened due to non-linearity during its propagation away from the ice keel.The internal surge eventually disintegrated into multi-modal and rank-ordered ISW packets with the largest having an amplitude of O(10)m.Sensitivity experiments demonstrated that the ISWs’amplitudes and energy were proportional to the varying ice keel depths and barotropic tidal fl ow amplitudes,but were insensitive to the changing ice keel widths.Typical ISWs can enhance the turbulent dissipation rate of O(10^(-6))W/kg along their propagation path.Further,heat entrainment induced by the wave-ice interaction can reach O(10)MJ/m per tidal cycle.This study reveals a particular ISW generation mechanism and process in the polar ice environment,which could be important in impacting the energy transfer and heat balance in the Arctic Ocean.
文摘This paper outlines a curriculum model for contemporary programme design for the purpose of embedding educational innovation and technology within an inter-professional nursing curriculum. It has been developed from work within the School of Nursing and Midwifery at Keele University during the re-write of both the nursing and midwifery curriculum. The Nursing and Midwifery Council (NMC) require approval of all recordable programmes every five years and as such the school took this review as an opportunity to explore the curriculum model currently in use and develop an approach that would facilitate the professional requirements of the programme alongside the embedding of innovative learning and teaching methodologies. The model springs from extensive application of contemporary pedagogy underpinning adult learning, and forces consideration of cognitive alignment within a multi-modal delivery framework [1]. The model builds upon the early work of Fowler and Mayes [2] and later work of Bird [3] who explored the antecedents and underpinning theory for success within online learning experiences. This model has greater reach;having strategic fit for acontemporary “technology enhanced learning” application within further and higher education [4], whilst ensuring the achievement of given professional standards [5].
文摘【目的】龙骨骨折(keel bone fracture, KBF)已成为影响蛋鸡健康和生产的重要福利问题。试验旨在评估产蛋期龙骨骨折的发生与否对产蛋后期的蛋鸡恐惧行为、生产性能和蛋品质的影响。【方法】选取60周龄的海兰褐蛋鸡和林甸鸡各100只,单笼饲养于传统叠层式鸡笼。利用触诊和便携式X光仪区分龙骨骨折蛋鸡和未骨折蛋鸡,通过紧张不动性测试(TI)、旷场试验(OFT)和惊吓反射试验(SRT)依次测量恐惧行为反应,并测定68周龄时蛋鸡的生产性能和蛋品质。【结果】在TI试验中,2个品种龙骨骨折蛋鸡的紧张不动时长显著高于正常蛋鸡(P<0.05)。在OFT试验中,龙骨骨折的海兰褐蛋鸡和林甸鸡在穿过的格子数、步数和在外圈停留的时间均显著低于正常蛋鸡(P<0.05),在内圈停留的时间显著高于正常蛋鸡(P<0.05),且骨折的海兰褐蛋鸡的运动潜伏期显著高于正常蛋鸡(P<0.05)。在SRT试验中,龙骨骨折蛋鸡惊吓反射总得分显著低于正常蛋鸡(P<0.05)。因此,龙骨骨折蛋鸡的恐惧行为反应较强烈。2个品种龙骨骨折蛋鸡的产蛋率显著低于正常蛋鸡(P<0.05),且骨折的海兰褐蛋鸡蛋形指数低于正常蛋鸡(P<0.05),其余蛋品质参数在骨折蛋鸡和正常蛋鸡中无显著性差异(P>0.05)。【结论】龙骨骨折加剧了蛋鸡的恐惧行为反应,降低了产蛋后期蛋鸡的福利水平和生产性能。
