To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The p...To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.展开更多
Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ens...Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these.In this work,the galloping time history of a wire with distorted(fixed in time)shape due to the formation of ice is analyzed numerically in the frame of afluid-solid coupling method for different wind speeds and levels of turbulence.The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift and drag coefficients due to ice accretion;nevertheless,the corresponding changes in the torsion coefficient are very significant and complicated.A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor.Through comparison of the galloping phenomena for different wind velocities,it is found that the related amplitude grows significantly with an increase of the wind speed.For a relatively large wind speed,the galloping amplitude is more sensitive to the turbulence intensity.Moreover,the larger the turbulence intensity,the larger the conductor’s vertical and horizontal galloping amplitudes after icing.The torsion angle also increases with an increase in the wind speed and turbulence intensity.展开更多
High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alterna...High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alternation of lift force and drag force.In this paper,the nonlinear dynamics and internal resonance of an iced cable under wind excitation are investigated.Considering the excitation caused by pulsed wind and the movement of the support,the nonlinear governing equations of motion of the iced cable are established using a three-degree-of-freedom model based on Hamilton's principle.By the Galerkin method,the partial differential equations are then discretized into ordinary differential equations.The method of multiple scales is then used to obtain the averaged equations of the iced cable,and the principal parametric resonance-1/2 subharmonic resonance and the 2:1 internal resonance are considered.The numerical simulations are performed to investigate the dynamic response of the iced cable.It is found that there exist periodic,multi-periodic,and chaotic motions of the iced cable subjected to wind excitation.展开更多
Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed....Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed. In numerical simulation, a three-node isoparametric cable element with three translational and one torsional degrees-of-freedom at each node is used to discretize the transmission line. The nonlinear dynamic system equation is solved with the Newmark time integration method and the Newton-Raphson nonlinear iteration. Numerical examples demonstrate the efficiency of the presented method and the developed finite element program. A new possible galloping mode, which may reflect the saturation phenomenon of a nonlinear dynamic system, is discovered under the condition that the lowest order of vertical natural frequency of the transmission line is approximately two times of the horizontal one.展开更多
Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On ...Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.展开更多
Whipped cream is a delicious topping.You can make it at home or buy it in a can.People often put it on desserts such as cakes and pies.Whipped cream is great on ice cream and fruit,too.Do you like cream puffs?Some hav...Whipped cream is a delicious topping.You can make it at home or buy it in a can.People often put it on desserts such as cakes and pies.Whipped cream is great on ice cream and fruit,too.Do you like cream puffs?Some have whipped cream in them.Whipped cream is also good on hot chocolate and coffee.So,enjoy whipped cream on desserts and hot drinks today.It's National Whipped Cream Day!展开更多
Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and...Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.展开更多
Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dime...Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process.展开更多
The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee...The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.展开更多
An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion pr...An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion process over aircraft wing surfaces.The multiphase flow simulation results of the wind-driven water runback(WDWR)flow are compared quantitatively with the experimental results in terms of the time-dependent variations of the water film thickness profiles and evolution of the front contact point of the runback water film flow.The underlying mechanism of the intermittent water runback behavior is elucidated by analyzing the time evolution of the airflow velocity and vorticity fields above the runback water film flow over the solid surface.To the best knowledge of the authors,the work presented here is the first successful attempt to numerically examine the transient runback characteristics of WDWR flows.It serves as an excellent benchmark case for the development of best practices to model the important micro-physical processes responsible for the transient water transport over aircraft wing surfaces.展开更多
The incorporation of SAEW and SI can effectively maintain the characteristics of texture in marine fish.This study aimed to investigate the relevance of cathepsin activity for texture and the establishment of a shelf-...The incorporation of SAEW and SI can effectively maintain the characteristics of texture in marine fish.This study aimed to investigate the relevance of cathepsin activity for texture and the establishment of a shelf-life model of mackerel(Pneumatophorus japonicus)stored at 4◦C.Before the cold storage,mackerel samples were exposed to flake ice(Control),slurry ice(SI),and slightly acidic electrolyzed water-slurry ice(SAEW-SI),respectively.Then the TVC,K-value,cathepsin activity,texture,and sensory attributes were investigated.The results showed that the TVC and K-value of samples in SAEW-SI group was significantly lower by approximately 1 log CFU/g and 17%than those in Control group(P<0.05).Meanwhile,there was a tendency to first increase and then decrease on the activities of cathepsin B,D and L.Results of texture profile analysis(TPA)clarified that SAEW-SI can markedly suppress the decrease of hardness,springiness and chewiness(P<0.05).During the experimental period,the highest sensory scores were obtained in SAEW-SI group.In addition,the heat map of correlation analysis suggested that texture attributes(hardness)were negatively correlated with cathepsin B(r=-0.66),cathepsin D(r=-0.49),and cathepsin L(r=-0.69),respectively.According to the principal component analysis(PCA)and analysis of linear regression,SAEW-SI treatment could effectively maintain mackerel quality and extend the estimated shelf-life of mackerel by at least 5 days compared to Control group.Therefore,SAEW-SI could be suggested as a novel strategy for cold-chain transportation in seafood industry.展开更多
I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade ...I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade is delicious.Iced tea is another popular summer drink.You can drink it with or without sugar.Many people also like iced coffee or cold brew coffee.Or you can just have a tall glass of cool water!展开更多
High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual s...High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual satellite sensors provide periodic sea ice obser-vations with spatial resolutions of tens of meters,information regarding changes that occur over short time intervals of minutes or hours is limited.In this study,a gridded ice-water classification dataset with a high temporal resolution was developed based on observations acquired by multiple satellite sensors in the Marginal Ice Zone(MIZ).This dataset-DynIceData-which combines Sentinel-1 Synthetic Aperture Radar(SAR)data with Gaofen-3(GF-3)SAR and SDGSAT-1 thermal infrared imagery was used to obtain observations of the MIZ with a range of temporal resolutions ran-ging from minutes to tens of hours.The areas of the Arctic covered include the Kara Sea,Beaufort Sea,and Greenland Sea during the period from August 2021 to August 2022.Object-oriented segmen-tation and thresholding were used to obtain the ice-water classifi-cation map from Sentinel-1 and GF-3 SAR image pairs and Sentinel-1 SAR and SDGSAT-1 thermal image pairs.The time interval between the images in each pair ranged from 1 minute to 68 hours.Ten-kilometer grid sample granules with a spatial resolution of 25 m for the GF-3 SAR data and 30 m for the SDGSAT-1 thermal data were used.The classification was verified as having an overall accuracy of at least 95.58%.The DynIceData dataset consists of 7338 samples,which could be used as reference data for further research on rapid changes in sea ice patterns at different short time scales and provide support for research on thermodynamic and dynamic models of sea ice in combination with other environmen-tal data,thus potentially improving the accuracy of sea ice forecast-ing using Artificial Intelligence.The dataset can be accessed at https://doi.org/10.57760/sciencedb.j00001.00784.展开更多
At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In th...At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In the bag is a cleanse set-six bottles of cold-pressed juices to be sipped as food substitutes for a day.They are for Guo Ling,a 24-year-old ad executive who has been“really getting into cleanses recently.”展开更多
At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In th...At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In the bag is a cleanse set-six bottles of cold-pressed juices to be sipped as food substitutes for a day.They are for Guo Ling,a 24-year-old ad executive who has been"really getting into cleanses recently."展开更多
近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、...近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51507106)China Postdoctoral Science Foundation(Grant No.2021M702371)。
文摘To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.
基金This work was supported in part by the National Natural Science Foundation of China[Grant No.51867013].
文摘Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these.In this work,the galloping time history of a wire with distorted(fixed in time)shape due to the formation of ice is analyzed numerically in the frame of afluid-solid coupling method for different wind speeds and levels of turbulence.The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift and drag coefficients due to ice accretion;nevertheless,the corresponding changes in the torsion coefficient are very significant and complicated.A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor.Through comparison of the galloping phenomena for different wind velocities,it is found that the related amplitude grows significantly with an increase of the wind speed.For a relatively large wind speed,the galloping amplitude is more sensitive to the turbulence intensity.Moreover,the larger the turbulence intensity,the larger the conductor’s vertical and horizontal galloping amplitudes after icing.The torsion angle also increases with an increase in the wind speed and turbulence intensity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11290152,11427801,and 11902220)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality,China(PHRIHLB).
文摘High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alternation of lift force and drag force.In this paper,the nonlinear dynamics and internal resonance of an iced cable under wind excitation are investigated.Considering the excitation caused by pulsed wind and the movement of the support,the nonlinear governing equations of motion of the iced cable are established using a three-degree-of-freedom model based on Hamilton's principle.By the Galerkin method,the partial differential equations are then discretized into ordinary differential equations.The method of multiple scales is then used to obtain the averaged equations of the iced cable,and the principal parametric resonance-1/2 subharmonic resonance and the 2:1 internal resonance are considered.The numerical simulations are performed to investigate the dynamic response of the iced cable.It is found that there exist periodic,multi-periodic,and chaotic motions of the iced cable subjected to wind excitation.
基金supported by the Science Foundation of the State Grid Corporation of China (No. 2007-1-77)the Natural Science Foundation Project of CQ CSTC of China (No. 2006BB6149)
文摘Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed. In numerical simulation, a three-node isoparametric cable element with three translational and one torsional degrees-of-freedom at each node is used to discretize the transmission line. The nonlinear dynamic system equation is solved with the Newmark time integration method and the Newton-Raphson nonlinear iteration. Numerical examples demonstrate the efficiency of the presented method and the developed finite element program. A new possible galloping mode, which may reflect the saturation phenomenon of a nonlinear dynamic system, is discovered under the condition that the lowest order of vertical natural frequency of the transmission line is approximately two times of the horizontal one.
文摘Ice crystal icing is an important cause of accidents in aircraft engines.Ice formation in aircraft engines can cause internal blades to freeze,affecting the quality of the air flow field and blocking the flow path.On the other hand,the entry of ice crystal particles into the combustion chamber can cause a decrease in temperature or even flameout,leading to engine surge or shutdown.Therefore,it is necessary to conduct multiphase flow tests on ice crystals for aircraft components such as aircraft engines.Conducting ice crystal multiphase flow tests on aircraft is an effective research method,but it requires the construction of an ice crystal multiphase flow test platform that meets relevant technical requirements.The paper focuses on the relevant experimental requirements and combines wind tunnel test structures to conduct multiphase flow numerical simulations on various forms of jet pipelines,obtaining particle motion distribution results.After comparison,the optimal form of jet structure is obtained,providing the best selection scheme for the design of relevant wind tunnel structures.
文摘Whipped cream is a delicious topping.You can make it at home or buy it in a can.People often put it on desserts such as cakes and pies.Whipped cream is great on ice cream and fruit,too.Do you like cream puffs?Some have whipped cream in them.Whipped cream is also good on hot chocolate and coffee.So,enjoy whipped cream on desserts and hot drinks today.It's National Whipped Cream Day!
文摘Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.
基金supported by the National Natural Science Foundation of China(Grant No.52178376)National Key R&D Program of China(Grant No.2022YFB2603301)Science and Technology Research and Development Program of China Railway Group Limited(Grant No.2022-ZD-13).
文摘Ice lens initiation is the core issue in understanding the dynamic process of frost heave.However,there are still limitations to find an adequate criterion for describing the formation of ice lens.A series of one-dimensional freezing tests is designed using the particle image velocimetry(PIV)method to monitor the frost heave and ice lens formation.The results show that the conventional parameters,such as displacement and velocity,cannot be used to track the ice lens formation,while the strain can be employed to detect the ice lens formation and investigate the freezing change patterns.This study proposes strain as a new criterion for assessing ice lens initiation,applicable across various soil types and freezing conditions(constant freezing and ramped freezing).The strain change in the region where the ice lens forms is the largest during the freezing process.Additionally,strain curves at the top of the soil samples can reveal different freezing patterns and distinguish the first and second frost heave stages.This newly developed technology enables continuous,non-destructive monitoring of ice lens initiation across diverse conditions and soil types,enhancing data visualization and three-dimensional modeling of freezing parameters while improving traditional methods by directly measuring velocity and strain in frost heave investigations.The study is expected to enhance the research of ice lens criterion and provide a new perspective for monitoring the freezing process.
基金supported by the National Natural Science Foundation of China(Grant Nos.12534013,12047561,and 12104507)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the National University of Defense Technology Research Fund Project.
文摘The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.
基金supported by the National Science Foundation(NSF)of the USA(Grant Nos.TIP-2140489,CBET-2313310,and CBET-2415347).
文摘An unsteady numerical simulation is conducted to examine the dynamic runback characteristics of a water film flow driven by a boundary layer airflow over a solid surface pertinent to the dynamic glaze ice accretion process over aircraft wing surfaces.The multiphase flow simulation results of the wind-driven water runback(WDWR)flow are compared quantitatively with the experimental results in terms of the time-dependent variations of the water film thickness profiles and evolution of the front contact point of the runback water film flow.The underlying mechanism of the intermittent water runback behavior is elucidated by analyzing the time evolution of the airflow velocity and vorticity fields above the runback water film flow over the solid surface.To the best knowledge of the authors,the work presented here is the first successful attempt to numerically examine the transient runback characteristics of WDWR flows.It serves as an excellent benchmark case for the development of best practices to model the important micro-physical processes responsible for the transient water transport over aircraft wing surfaces.
基金supported by China Agriculture Research System of MOF and MARA(CARS-47)the National Key R&D Program of China(2019YFD0901602)Ability promotion project of Shanghai Municipal Science and Technology Commission Engineering Center(19DZ2284000).
文摘The incorporation of SAEW and SI can effectively maintain the characteristics of texture in marine fish.This study aimed to investigate the relevance of cathepsin activity for texture and the establishment of a shelf-life model of mackerel(Pneumatophorus japonicus)stored at 4◦C.Before the cold storage,mackerel samples were exposed to flake ice(Control),slurry ice(SI),and slightly acidic electrolyzed water-slurry ice(SAEW-SI),respectively.Then the TVC,K-value,cathepsin activity,texture,and sensory attributes were investigated.The results showed that the TVC and K-value of samples in SAEW-SI group was significantly lower by approximately 1 log CFU/g and 17%than those in Control group(P<0.05).Meanwhile,there was a tendency to first increase and then decrease on the activities of cathepsin B,D and L.Results of texture profile analysis(TPA)clarified that SAEW-SI can markedly suppress the decrease of hardness,springiness and chewiness(P<0.05).During the experimental period,the highest sensory scores were obtained in SAEW-SI group.In addition,the heat map of correlation analysis suggested that texture attributes(hardness)were negatively correlated with cathepsin B(r=-0.66),cathepsin D(r=-0.49),and cathepsin L(r=-0.69),respectively.According to the principal component analysis(PCA)and analysis of linear regression,SAEW-SI treatment could effectively maintain mackerel quality and extend the estimated shelf-life of mackerel by at least 5 days compared to Control group.Therefore,SAEW-SI could be suggested as a novel strategy for cold-chain transportation in seafood industry.
文摘I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade is delicious.Iced tea is another popular summer drink.You can drink it with or without sugar.Many people also like iced coffee or cold brew coffee.Or you can just have a tall glass of cool water!
基金funded by the National Key Research and Development Program of China(No.2019YFE0105700 and No.2017YFE0111700)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA19070201 and No.XDA19070102)+1 种基金the Innovative Research Program of the International Research Center of Big Data for Sustainable Development Goals(No.CBAS2022IRP08)the International Partnership Program of the Chinese Academy of Sciences“Remote Sensing and Modeling of the Snow and Ice Physical Process”(RSMSIP No.313GJHZ2022054MI).
文摘High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual satellite sensors provide periodic sea ice obser-vations with spatial resolutions of tens of meters,information regarding changes that occur over short time intervals of minutes or hours is limited.In this study,a gridded ice-water classification dataset with a high temporal resolution was developed based on observations acquired by multiple satellite sensors in the Marginal Ice Zone(MIZ).This dataset-DynIceData-which combines Sentinel-1 Synthetic Aperture Radar(SAR)data with Gaofen-3(GF-3)SAR and SDGSAT-1 thermal infrared imagery was used to obtain observations of the MIZ with a range of temporal resolutions ran-ging from minutes to tens of hours.The areas of the Arctic covered include the Kara Sea,Beaufort Sea,and Greenland Sea during the period from August 2021 to August 2022.Object-oriented segmen-tation and thresholding were used to obtain the ice-water classifi-cation map from Sentinel-1 and GF-3 SAR image pairs and Sentinel-1 SAR and SDGSAT-1 thermal image pairs.The time interval between the images in each pair ranged from 1 minute to 68 hours.Ten-kilometer grid sample granules with a spatial resolution of 25 m for the GF-3 SAR data and 30 m for the SDGSAT-1 thermal data were used.The classification was verified as having an overall accuracy of at least 95.58%.The DynIceData dataset consists of 7338 samples,which could be used as reference data for further research on rapid changes in sea ice patterns at different short time scales and provide support for research on thermodynamic and dynamic models of sea ice in combination with other environmen-tal data,thus potentially improving the accuracy of sea ice forecast-ing using Artificial Intelligence.The dataset can be accessed at https://doi.org/10.57760/sciencedb.j00001.00784.
文摘At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In the bag is a cleanse set-six bottles of cold-pressed juices to be sipped as food substitutes for a day.They are for Guo Ling,a 24-year-old ad executive who has been“really getting into cleanses recently.”
文摘At 9am on a rainy Wednesday in Shanghai,a delivery guy carrying a small bag squeezes past white-collar workers in a crammed elevator of a Xintiandi office building and emerges into the lobby of a local ad agency.In the bag is a cleanse set-six bottles of cold-pressed juices to be sipped as food substitutes for a day.They are for Guo Ling,a 24-year-old ad executive who has been"really getting into cleanses recently."
文摘近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。
