The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on sn...The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on snake scales to avoid severe wear.Among them,the research towards the keeled structure on snake scales is missing.Therefore,in this research,the wear resistance improvement of the keeled structure on the snake scales and the overlapped distribution of snake scales are investigated.The keeled and smooth snake scales were 3D printed and they were distributed on the substrate in the overlapped or paralleled ways.Besides these four samples with keeled/smooth scales and overlapped/paralleled distributed,there is also a reference sample with the same thickness.Based on the tribology test,the number of grooves of samples with the keeled structures is higher than that of samples with smooth surfaces,which indicates that the keeled structure dramatically enhances the wear resistance of snake scales,especially during the wear in the vertical direction.The experiment on surface morphology greatly compromised the result of the tribology test.In addition,the bottom portion of the keeled snake scales can be protected by the keeled structure.Besides,the overlapped distribution can protect the central region of snake scales and provide double-layer protection of the snake body.Overall,the keeled structure and the overlapped distribution play a significant part in the improvement of wear resistance of the snake skin.These findings can enhance the knowledge of the reptiles-mimic surface structure and facilitate the application of military uniforms under high-wear conditions.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
Since the roll damping of ships has significant effects of viscosity, it is difficult to calculate it theoretically. Therefore, experimental results or some prediction methods are used to get the roll damping in desig...Since the roll damping of ships has significant effects of viscosity, it is difficult to calculate it theoretically. Therefore, experimental results or some prediction methods are used to get the roll damping in design stage of ships. Among some prediction methods, Ikeda＇s one is widely used in many ship motion computer programs. Using the method, the roll damping of various ship hulls with various bilge keels can be calculated to investigate its characteristics. To calculate the roll damping of each ship, detailed data of the ship are needed to input. Therefore, a simpler prediction method is expected in primary design stage. Such a simple method must be useful to validate the results obtained by a computer code to predict it on the basis of Ikeda＇s method, too. On the basis of the predicted roll damping by Ikeda＇s method for various ships, a very simple prediction formula of the roll damping of ships is deduced in the present paper. Ship hull forms are systematically changed by changing length, beam, draft, mid-ship sectional coefficient and prismatic coefficient. It is found, however, that this simple formula can not be used for ships that have high position of the center of gravity. A modified method to improve accuracy for such ships is proposed.展开更多
Is it coincidence that two of the largest outpourings of lava in Earth’s history,the Deccan Traps and Siberian Traps,occurred simultaneously with the Cretaceous-Tertiary(KT)and Permian-Triassic(PT)extinctions respect...Is it coincidence that two of the largest outpourings of lava in Earth’s history,the Deccan Traps and Siberian Traps,occurred simultaneously with the Cretaceous-Tertiary(KT)and Permian-Triassic(PT)extinctions respectively?Either the outpourings of lava caused the extinctions or what caused the extinctions caused the lava outpourings.It is proposed that the primary cause of both extinctions is a bolide impact and that the traps are the antipodal outpourings caused by the impacts.Is it coincidence that the Hawaiian Hotspot lies in the middle of the Pacific Basin?The formation of the hotspot must be related to the formation of the basin.It is proposed that a very large bolide impact created both the Hawaiian Hotspot and the Pacific Basin.These propositions infer several corollaries.The Earth first formed a global continental crust.This global crust lasted until a bolide impact destroyed 2/3 of it to form the Pacific Basin and Hawaiian Hotspot.The impact also caused the PT extinction and the eruption of the Siberian Traps.Subduction plate tectonics did not operate on Earth until the basin crust became negatively buoyant and began to subduct.The KT impact was a smaller version of the PT impact.It broke up crust off the west coast of North America and formed the Yellowstone Hotspot.It also caused the KT extinction and the eruption of the Deccan Traps.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
The article presents evidence regarding the origin of Spirula from spiral-shelled forms. The geological age of the species is revised from the Miocene to the Jurassic. The causes of the reorientation of the shell are ...The article presents evidence regarding the origin of Spirula from spiral-shelled forms. The geological age of the species is revised from the Miocene to the Jurassic. The causes of the reorientation of the shell are elucidated. The mode of life of the mollusk is specified. The influence of the theory on facts perception is shown.展开更多
Congenital laryngeal web is an otolaryngology rarity, which occurs due to incomplete recanalization of the larynx. We report a case of a 22 year-old patient who presented with a congenital anterior laryngeal web. We s...Congenital laryngeal web is an otolaryngology rarity, which occurs due to incomplete recanalization of the larynx. We report a case of a 22 year-old patient who presented with a congenital anterior laryngeal web. We shall discuss the presentation, diagnosis, management and postoperative follow up of the case.展开更多
Transoral microresection for treatment of vocal cord lesions involving the anterior commissure may result in anterior glottic webs. In this study, we retrospectively reviewed 54 patients who underwent microsurgery for...Transoral microresection for treatment of vocal cord lesions involving the anterior commissure may result in anterior glottic webs. In this study, we retrospectively reviewed 54 patients who underwent microsurgery for bilateral lesions involving the anterior commissure and categorized them into two groups. The keel placement and control groups received endoscopic keel placement and mitomycin C, respectively. During the follow-up of at least 1 year, the laryngeal web formation rate significantly decreased in the keel placement group compared with that in the control group （18.6% versus 54.5%, P 〈 0.05）. Furthermore, the voice handicap index-10 scores for patients without web formation decreased in both the keel placement and control groups （P 〈 0.0001 and P 〈 0.001, respectively）. A pseudomembrane covering the vocal cords was detected in 16.3% （7 of 43） cases after keel removal. A total of 100% （7 of 7） of these cases and 2.8% （1 of 36） of the other cases formed laryngeal webs （P 〈 0.0001）. Endoscopic keel placement could be an effective method for preventing anterior glottic webs after surgery for bilateral vocal cord diseases involving the anterior commissure. The pseudomembrane observed at the time of keel removal may imply a high risk of web formation.展开更多
基金funded By Key Scientific And Technological Program Of Ningbo City(No.2021Z108)Yongjiang Talent Introduction Programme(No.2021A-154-G).
文摘The movement mode of snakes is crawling,and the living environment of snakes with numerous branches and stones will cause plenty of wear for the snake scales.There are plenty of surface structures and morphology on snake scales to avoid severe wear.Among them,the research towards the keeled structure on snake scales is missing.Therefore,in this research,the wear resistance improvement of the keeled structure on the snake scales and the overlapped distribution of snake scales are investigated.The keeled and smooth snake scales were 3D printed and they were distributed on the substrate in the overlapped or paralleled ways.Besides these four samples with keeled/smooth scales and overlapped/paralleled distributed,there is also a reference sample with the same thickness.Based on the tribology test,the number of grooves of samples with the keeled structures is higher than that of samples with smooth surfaces,which indicates that the keeled structure dramatically enhances the wear resistance of snake scales,especially during the wear in the vertical direction.The experiment on surface morphology greatly compromised the result of the tribology test.In addition,the bottom portion of the keeled snake scales can be protected by the keeled structure.Besides,the overlapped distribution can protect the central region of snake scales and provide double-layer protection of the snake body.Overall,the keeled structure and the overlapped distribution play a significant part in the improvement of wear resistance of the snake skin.These findings can enhance the knowledge of the reptiles-mimic surface structure and facilitate the application of military uniforms under high-wear conditions.
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Since the roll damping of ships has significant effects of viscosity, it is difficult to calculate it theoretically. Therefore, experimental results or some prediction methods are used to get the roll damping in design stage of ships. Among some prediction methods, Ikeda＇s one is widely used in many ship motion computer programs. Using the method, the roll damping of various ship hulls with various bilge keels can be calculated to investigate its characteristics. To calculate the roll damping of each ship, detailed data of the ship are needed to input. Therefore, a simpler prediction method is expected in primary design stage. Such a simple method must be useful to validate the results obtained by a computer code to predict it on the basis of Ikeda＇s method, too. On the basis of the predicted roll damping by Ikeda＇s method for various ships, a very simple prediction formula of the roll damping of ships is deduced in the present paper. Ship hull forms are systematically changed by changing length, beam, draft, mid-ship sectional coefficient and prismatic coefficient. It is found, however, that this simple formula can not be used for ships that have high position of the center of gravity. A modified method to improve accuracy for such ships is proposed.
文摘Is it coincidence that two of the largest outpourings of lava in Earth’s history,the Deccan Traps and Siberian Traps,occurred simultaneously with the Cretaceous-Tertiary(KT)and Permian-Triassic(PT)extinctions respectively?Either the outpourings of lava caused the extinctions or what caused the extinctions caused the lava outpourings.It is proposed that the primary cause of both extinctions is a bolide impact and that the traps are the antipodal outpourings caused by the impacts.Is it coincidence that the Hawaiian Hotspot lies in the middle of the Pacific Basin?The formation of the hotspot must be related to the formation of the basin.It is proposed that a very large bolide impact created both the Hawaiian Hotspot and the Pacific Basin.These propositions infer several corollaries.The Earth first formed a global continental crust.This global crust lasted until a bolide impact destroyed 2/3 of it to form the Pacific Basin and Hawaiian Hotspot.The impact also caused the PT extinction and the eruption of the Siberian Traps.Subduction plate tectonics did not operate on Earth until the basin crust became negatively buoyant and began to subduct.The KT impact was a smaller version of the PT impact.It broke up crust off the west coast of North America and formed the Yellowstone Hotspot.It also caused the KT extinction and the eruption of the Deccan Traps.
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The article presents evidence regarding the origin of Spirula from spiral-shelled forms. The geological age of the species is revised from the Miocene to the Jurassic. The causes of the reorientation of the shell are elucidated. The mode of life of the mollusk is specified. The influence of the theory on facts perception is shown.
文摘Congenital laryngeal web is an otolaryngology rarity, which occurs due to incomplete recanalization of the larynx. We report a case of a 22 year-old patient who presented with a congenital anterior laryngeal web. We shall discuss the presentation, diagnosis, management and postoperative follow up of the case.
文摘Transoral microresection for treatment of vocal cord lesions involving the anterior commissure may result in anterior glottic webs. In this study, we retrospectively reviewed 54 patients who underwent microsurgery for bilateral lesions involving the anterior commissure and categorized them into two groups. The keel placement and control groups received endoscopic keel placement and mitomycin C, respectively. During the follow-up of at least 1 year, the laryngeal web formation rate significantly decreased in the keel placement group compared with that in the control group （18.6% versus 54.5%, P 〈 0.05）. Furthermore, the voice handicap index-10 scores for patients without web formation decreased in both the keel placement and control groups （P 〈 0.0001 and P 〈 0.001, respectively）. A pseudomembrane covering the vocal cords was detected in 16.3% （7 of 43） cases after keel removal. A total of 100% （7 of 7） of these cases and 2.8% （1 of 36） of the other cases formed laryngeal webs （P 〈 0.0001）. Endoscopic keel placement could be an effective method for preventing anterior glottic webs after surgery for bilateral vocal cord diseases involving the anterior commissure. The pseudomembrane observed at the time of keel removal may imply a high risk of web formation.
