Ocean fronts play important roles in nutrient transport and in the shaping ecological patterns.Frontal zones in small bays are typically small in scale,have a complex structure,and they are spatially and temporally va...Ocean fronts play important roles in nutrient transport and in the shaping ecological patterns.Frontal zones in small bays are typically small in scale,have a complex structure,and they are spatially and temporally variable,but there are limited data on how biological communities respond to this variation.Hangzhou Bay,a mediumsized estuary in China,is an ideal place in which to study the response of plankton to small-scale ocean fronts,because three water masses(Qiantang River Diluted Water,Changjiang River Diluted Water,and the East China Sea current) converge here and form dynamic salinity fronts throughout the year.We investigate zooplankton communities,and temperature,salinity and chlorophyll a(Chl a) in Hangzhou Bay in June(wet perio d) and December(dry period) of 2022 and examine the dominant environmental factors that affect zooplankton community spatial variability.We then match the spatial distributions of zooplankton communities with those of salinity fronts.S alinity is the most important explanatory variable to affect zooplankton community spatial variability during both wet and dry periods,in that it contributes>60% of the variability in community structure.Furthermore,the spatial distributions of zooplankton match well with salinity fronts.During December,with weaker Qiantang River Diluted Water and a stronger secondary Changjiang River Plume,zooplankton communities occur in moderate salinity(MS,salinity range 15.6±2.2) and high salinity(HS,22.4±1.7) regions,and their ecological boundaries closely match the Qiantang River Diluted Water front.In June,different zooplankton communities occur in low salinity(LS,3.9±1.0),MS(11.7±3.6) and HS(21.3±1.9) regions.Although the LS region occurs abnormally in the central bay rather than its apex because of the anomalous influence of rising and falling tides during the sampling perio d,the ecological boundaries still match salinity interfaces.Low-salinity or brackish-water zooplankter taxa are relatively more abundant in LS or MS regions,and the biomass and abundance of zooplankton is higher in the MS region.展开更多
With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the pr...With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies.Taking the industrialintensive Jinsha River Basin as typical area,a two-dimensional hydrodynamic water quality model coupled with Soil andWater Assessment Tool(SWAT)model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution.The effects of hydro-climate change,hydropower station construction and non-point source emissions on Aswere quantified based on the coupled model.The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream.Due to the enhanced rainfall,the As concentration was significantly higher during the rainy season than the dry season.Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration,but also affected the adsorption and desorption of As in sediment.Furthermore,As concentration increased with the input of non-point source pollution,with the maximum increase about 30%,resulting that non-point sources contributed important pollutant impacts to waterways.The coupled model used in pollutant behavior analysis is generalwith high potential application to predict and mitigate water pollution.展开更多
Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubri...Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubricant additives,their macromolecular analogs have been rarely considered yet to develop environmentally friendly lubricant additives.In this work,a series of boron-containing copolymers have been synthesized by free-radical copolymerization of stearyl methacrylate and isopropenyl boronic acid pinacol ester with different feeding ratios(S_(n)-r-B_(m),n=1,m=1/3,1,2,3,5,9).The resulting copolymers of S_(n)-r-B_(m)(n=1,m=1/3,1,2,3,5)are readily dispersed in the PAO-10 base oil and form micelle-like aggregates with hydrodynamic diameters ranging from 9.7 to 52 nm.SRV-IV oscillating reciprocating tribological tests on ball-on-flat steel pairs show that compared with the base oil of PAO-10,the friction coefficients and wear volumes of the base oil solutions of S_(n)-r-B_(m)decrease considerably up to 62%and 97%,respectively.Moreover,the base oil solution of S_(1)-r-B_(1)exhibits an excellent load-bearing capacity of(850±100)N.These superior lubricating properties are due to the formation of protective tribofilms comprising S_(n)-r-B_(m),boron oxide,and iron oxide compounds on the lubricated steel surface.Therefore,the boron-containing copolymers can be regarded as a novel class of environmentally friendly lubricating oil macroadditives for efficient friction and wear reduction without sulfur and phosphorus elements.展开更多
The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific ...The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific configuration of applied magnetics fields and current and can persist up to 20 K,much higher than the Ne'el temperature(T_(N)≈1.9 K).Experiments and first-principles calculations suggest that the observed large negative MR is derived from a magnetic field that reconstructs the band structure and induces a Weyl point,which changes the carrier concentration.展开更多
Nature evolves soft but structural architectures with typical wet/lubricous/adhesive behavior,as well as tunable interface functionalities,such as superhydrophilicity,superhydrophobic,superlubricity,high adhesion,etc....Nature evolves soft but structural architectures with typical wet/lubricous/adhesive behavior,as well as tunable interface functionalities,such as superhydrophilicity,superhydrophobic,superlubricity,high adhesion,etc.In order to simulate this,new chemistry modification methods,novel polymers materials and advanced manufacture techniques are developed for engineering diverse bioinspired wet/lubricous/adhesive soft matter systems.This review focuses on two typical interface functionalities of soft architectures in nature:wet lubrication and wet adhesion.Correspondingly,systematic summaries of recent progress for constructing bioinspired wet/lubricious/adhesive soft matter systems are proposed,including the surface grafting methods to construct hydrophilic wet lubrication surfaces,the bionic design of mechanically robust and structured soft matter lubrication materials,the novel preparation of high-performance biomimetic wet adhesion materials,and the advanced manufacture of 3D soft matter-based wet/lubricious devices.Subsequently,the current strategies relying on diverse regulation factors including surface hydration/roughness,surface intrinsic states,bulk mechanics,as well as multi-factors synergy,are introduced and discussed for achieving dynamic friction or adhesion control of bioinspired soft matter lubrication/adhesion systems.Finally,the existing problems,challenges and future development directions of bioinspired wet/lubricious/adhesive soft matter materials and devices are discussed.This review provides clear guidance for designing bioinspired soft matter-based lubrication,adhesion,or adhesion-lubrication switchable systems,and would act as a necessary research handbook in the field of surface/interface wettability engineering,bioengineering,medical devices,soft robotics,etc.展开更多
Considering the difficulty of integrating the depth points of nautical charts of the East China Sea into a global high-precision Grid Digital Elevation Model(Grid-DEM),we proposed a“Fusion based on Image Recognition(...Considering the difficulty of integrating the depth points of nautical charts of the East China Sea into a global high-precision Grid Digital Elevation Model(Grid-DEM),we proposed a“Fusion based on Image Recognition(FIR)”method for multi-sourced depth data fusion,and used it to merge the electronic nautical chart dataset(referred to as Chart2014 in this paper)with the global digital elevation dataset(referred to as Globalbath2002 in this paper).Compared to the traditional fusion of two datasets by direct combination and interpolation,the new Grid-DEM formed by FIR can better represent the data characteristics of Chart2014,reduce the calculation difficulty,and be more intuitive,and,the choice of different interpolation methods in FIR and the influence of the“exclusion radius R”parameter were discussed.FIR avoids complex calculations of spatial distances among points from different sources,and instead uses spatial exclusion map to perform one-step screening based on the exclusion radius R,which greatly improved the fusion status of a reliable dataset.The fusion results of different experiments were analyzed statistically with root mean square error and mean relative error,showing that the interpolation methods based on Delaunay triangulation are more suitable for the fusion of nautical chart depth of China,and factors such as the point density distribution of multiple source data,accuracy,interpolation method,and various terrain conditions should be fully considered when selecting the exclusion radius R.展开更多
An experimental and finite element simulation investigation are conducted to study the deformation patterns of steel targets during the penetration process of tungsten alloy long rods,as well as the influence of stren...An experimental and finite element simulation investigation are conducted to study the deformation patterns of steel targets during the penetration process of tungsten alloy long rods,as well as the influence of strength of the target on the deformation patterns.The experimental results revealed slight mass loss in the first layer of the steel target during the transient entrance phase,with an extremely negligible loss in target mass during the quasi-steady penetration phase.The results of macro-analysis,micro-analysis and simulation show that the eroded target material migrated towards the periphery of the crater,causing an increase in the target's thickness,remained within the target,instead of flowing out of the crater.Therefore,the process of long rods penetrating the metal target is considered as a process of backward extrusion.By combining the backward extrusion theory with energy conservation,a penetration depth model for long rods penetrating a metal target,taking into account both the diameter of the crater and the friction coefficient between the rod and the target,has been established.Although the model is not yet perfect,it innovatively applies the principles of solid mechanics to the study of long rod penetration.Additionally,it takes into account the friction coefficient between the rod and the target during the penetration process.Therefore,this model provides a new research direction for future studies on long rod penetration.展开更多
Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase tra...Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase transition have rarely been reported yet.Herein,we discovered ferroelasticity in a pair of organic enantiomers,(1S and/or 1R)-2,10-camphorsultam(S-and R-CPS),which undergoes a high-T_(c)plastic phase transition.Both large entropies change of∼45 J mol^(-1)K^(-1)and evidently ductile deformation process confirm the plastic phase feature.Strip-like ferroelastic domain patterns and bidirectional domain movements have been observed via polarized light microscopy and nanoindentation technique,respectively.This work highlights the discovery of organic ferroelastic combining the features of enantiomers and plastic phase transition,which contributes insights into exploration of organic multifunctional materials.展开更多
Five meroterpenoids,rhodonoids K-M(1-2),daurichromene E(3),and grifolins A-B(4-5),together with seven known compounds(6-12),were isolated from Rhododendron anthopogonoides.The chemical structures of these compounds we...Five meroterpenoids,rhodonoids K-M(1-2),daurichromene E(3),and grifolins A-B(4-5),together with seven known compounds(6-12),were isolated from Rhododendron anthopogonoides.The chemical structures of these compounds were elucidated through comprehensive analysis of high-resolution electrospray ionization mass spectrometry(HR-ESI-MS),ultraviolet(UV),infrared spectroscopy(IR),and nuclear magnetic resonance(NMR)data.Their absolute configurations were determined by comparing experimental electronic circular dichroism(ECD)spectra with computed values.Notably,compounds 1 and 3 demonstrated significant inhibitory effects on lipopolysaccharide(LPS)-induced inflammation in RAW264.7 cells.These compounds markedly suppressed the mRNA expressions of inflammatory factors,including interleukin(IL)-1β,IL-6,and tumor necrosis factor-α(TNF-α)while also down-regulating the protein expressions of inducible nitric oxide synthase(iNOS)and cyclooxygenase-2(COX-2).展开更多
A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the ph...A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the phase mask scanning technique, serving as the mirrors in an all-fiber laser linear resonator. Leveraging the polarization dependence of the RCFBG through side exposure, we can readily achieve switchable single-wavelength, dual-wavelength, or triple-wavelength laser outputs by adjusting the polarization controller(PC) inside the resonator. Additionally, three distinct modes, namely, cylindrical vector beam(CVB), fundamental and mixed modes, are successfully obtained in single-wavelength laser operation.Azimuthally or radially polarized lasers can be realized by tuning two PCs inside and outside the resonator while operating in CVB mode. This innovative multi-wavelength and transversely mode-switchable fiber laser based on RCFBGs holds significant potential for applications in wavelength division multiplexing and mode division multiplexing systems.展开更多
By examining a specific case of compensating for nighttime construction noise in Beijing’s construction projects,we explored how the costs of mitigating construction noise disturbance could be fairly distributed amon...By examining a specific case of compensating for nighttime construction noise in Beijing’s construction projects,we explored how the costs of mitigating construction noise disturbance could be fairly distributed among multiple construction projects near residential areas.In this process,the local government played a crucial coordinating role.According to regulations,construction units must include the costs of preventing and controlling construction noise pollution in the project cost.The construction contract should clearly specify the construction unit’s responsibility for noise pollution prevention and control.After signing the contract,the construction unit should promptly undertake relevant measures to minimize disturbances caused by nighttime construction,aiming to reduce the adverse impacts on the community and ensure the smooth progress of the construction project.展开更多
Acoustic reflection imaging logging technology can detect and evaluate the development of reflection anomalies,such as fractures,caves and faults,within a range of tens of meters from the wellbore,greatly expanding th...Acoustic reflection imaging logging technology can detect and evaluate the development of reflection anomalies,such as fractures,caves and faults,within a range of tens of meters from the wellbore,greatly expanding the application scope of well logging technology.This article reviews the development history of the technology and focuses on introducing key methods,software,and on-site applications of acoustic reflection imaging logging technology.Based on the analyses of major challenges faced by existing technologies,and in conjunction with the practical production requirements of oilfields,the further development directions of acoustic reflection imaging logging are proposed.Following the current approach that utilizes the reflection coefficients,derived from the computation of acoustic slowness and density,to perform seismic inversion constrained by well logging,the next frontier is to directly establish the forward and inverse relationships between the downhole measured reflection waves and the surface seismic reflection waves.It is essential to advance research in imaging of fractures within shale reservoirs,the assessment of hydraulic fracturing effectiveness,the study of geosteering while drilling,and the innovation in instruments of acoustic reflection imaging logging technology.展开更多
基金The National Key Research and Development Program of China under contact No.2021YFC3101702the Natural Science Foundation of Zhejiang Province under contact Nos LY22D060006 and LY14D060007+1 种基金the Key R&D Program of Zhejiang under contact No.2022C03044the Project of Long-term Observation and Research Plan in the Changjiang Estuary and Adjacent East China Sea (LORCE) under contact No.SZ2001。
文摘Ocean fronts play important roles in nutrient transport and in the shaping ecological patterns.Frontal zones in small bays are typically small in scale,have a complex structure,and they are spatially and temporally variable,but there are limited data on how biological communities respond to this variation.Hangzhou Bay,a mediumsized estuary in China,is an ideal place in which to study the response of plankton to small-scale ocean fronts,because three water masses(Qiantang River Diluted Water,Changjiang River Diluted Water,and the East China Sea current) converge here and form dynamic salinity fronts throughout the year.We investigate zooplankton communities,and temperature,salinity and chlorophyll a(Chl a) in Hangzhou Bay in June(wet perio d) and December(dry period) of 2022 and examine the dominant environmental factors that affect zooplankton community spatial variability.We then match the spatial distributions of zooplankton communities with those of salinity fronts.S alinity is the most important explanatory variable to affect zooplankton community spatial variability during both wet and dry periods,in that it contributes>60% of the variability in community structure.Furthermore,the spatial distributions of zooplankton match well with salinity fronts.During December,with weaker Qiantang River Diluted Water and a stronger secondary Changjiang River Plume,zooplankton communities occur in moderate salinity(MS,salinity range 15.6±2.2) and high salinity(HS,22.4±1.7) regions,and their ecological boundaries closely match the Qiantang River Diluted Water front.In June,different zooplankton communities occur in low salinity(LS,3.9±1.0),MS(11.7±3.6) and HS(21.3±1.9) regions.Although the LS region occurs abnormally in the central bay rather than its apex because of the anomalous influence of rising and falling tides during the sampling perio d,the ecological boundaries still match salinity interfaces.Low-salinity or brackish-water zooplankter taxa are relatively more abundant in LS or MS regions,and the biomass and abundance of zooplankton is higher in the MS region.
基金supported by the National Key Research and Development Program of China(No.2017YFC1502504)the National Natural Science Foundation of China(No.41877531).
文摘With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies.Taking the industrialintensive Jinsha River Basin as typical area,a two-dimensional hydrodynamic water quality model coupled with Soil andWater Assessment Tool(SWAT)model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution.The effects of hydro-climate change,hydropower station construction and non-point source emissions on Aswere quantified based on the coupled model.The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream.Due to the enhanced rainfall,the As concentration was significantly higher during the rainy season than the dry season.Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration,but also affected the adsorption and desorption of As in sediment.Furthermore,As concentration increased with the input of non-point source pollution,with the maximum increase about 30%,resulting that non-point sources contributed important pollutant impacts to waterways.The coupled model used in pollutant behavior analysis is generalwith high potential application to predict and mitigate water pollution.
文摘Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubricant additives,their macromolecular analogs have been rarely considered yet to develop environmentally friendly lubricant additives.In this work,a series of boron-containing copolymers have been synthesized by free-radical copolymerization of stearyl methacrylate and isopropenyl boronic acid pinacol ester with different feeding ratios(S_(n)-r-B_(m),n=1,m=1/3,1,2,3,5,9).The resulting copolymers of S_(n)-r-B_(m)(n=1,m=1/3,1,2,3,5)are readily dispersed in the PAO-10 base oil and form micelle-like aggregates with hydrodynamic diameters ranging from 9.7 to 52 nm.SRV-IV oscillating reciprocating tribological tests on ball-on-flat steel pairs show that compared with the base oil of PAO-10,the friction coefficients and wear volumes of the base oil solutions of S_(n)-r-B_(m)decrease considerably up to 62%and 97%,respectively.Moreover,the base oil solution of S_(1)-r-B_(1)exhibits an excellent load-bearing capacity of(850±100)N.These superior lubricating properties are due to the formation of protective tribofilms comprising S_(n)-r-B_(m),boron oxide,and iron oxide compounds on the lubricated steel surface.Therefore,the boron-containing copolymers can be regarded as a novel class of environmentally friendly lubricating oil macroadditives for efficient friction and wear reduction without sulfur and phosphorus elements.
基金financially supported by the National Key R&D Program of China(No.2022YFA1402600)the National Natural Science Foundation of China(Nos.12304150 and 52161135108)support by the National Science Centre(Poland)(No.2021/40/Q/ST5/00066)。
文摘The angular dependence of magnetoresistance(MR)in antiferromagnetic half-Heusler HoAuSn single crystals has been systematically studied.Negative MR,as large as~99%,is observed at 9 T,is not restricted to the specific configuration of applied magnetics fields and current and can persist up to 20 K,much higher than the Ne'el temperature(T_(N)≈1.9 K).Experiments and first-principles calculations suggest that the observed large negative MR is derived from a magnetic field that reconstructs the band structure and induces a Weyl point,which changes the carrier concentration.
基金supported by the National Natural Science Foundation of China(22032006,52075522,52322506)West Light Foundation of The Chinese Academy of Sciences(xbzg-zdsys-202211)+2 种基金Major Science and Technology Project of Gansu Province(No.23ZDGA011)the Youth Innovation Promotion Association of The Chinese Academy of Sciences(Y2023114)Key Research Project of Shandong Provincial Natural Science Foundation(ZR2021ZD27).
文摘Nature evolves soft but structural architectures with typical wet/lubricous/adhesive behavior,as well as tunable interface functionalities,such as superhydrophilicity,superhydrophobic,superlubricity,high adhesion,etc.In order to simulate this,new chemistry modification methods,novel polymers materials and advanced manufacture techniques are developed for engineering diverse bioinspired wet/lubricous/adhesive soft matter systems.This review focuses on two typical interface functionalities of soft architectures in nature:wet lubrication and wet adhesion.Correspondingly,systematic summaries of recent progress for constructing bioinspired wet/lubricious/adhesive soft matter systems are proposed,including the surface grafting methods to construct hydrophilic wet lubrication surfaces,the bionic design of mechanically robust and structured soft matter lubrication materials,the novel preparation of high-performance biomimetic wet adhesion materials,and the advanced manufacture of 3D soft matter-based wet/lubricious devices.Subsequently,the current strategies relying on diverse regulation factors including surface hydration/roughness,surface intrinsic states,bulk mechanics,as well as multi-factors synergy,are introduced and discussed for achieving dynamic friction or adhesion control of bioinspired soft matter lubrication/adhesion systems.Finally,the existing problems,challenges and future development directions of bioinspired wet/lubricious/adhesive soft matter materials and devices are discussed.This review provides clear guidance for designing bioinspired soft matter-based lubrication,adhesion,or adhesion-lubrication switchable systems,and would act as a necessary research handbook in the field of surface/interface wettability engineering,bioengineering,medical devices,soft robotics,etc.
基金Supported by the National Key R&D Program of China (No.2023YFC3008100)the National Natural Science Foundation of China (No.U23A2033)
文摘Considering the difficulty of integrating the depth points of nautical charts of the East China Sea into a global high-precision Grid Digital Elevation Model(Grid-DEM),we proposed a“Fusion based on Image Recognition(FIR)”method for multi-sourced depth data fusion,and used it to merge the electronic nautical chart dataset(referred to as Chart2014 in this paper)with the global digital elevation dataset(referred to as Globalbath2002 in this paper).Compared to the traditional fusion of two datasets by direct combination and interpolation,the new Grid-DEM formed by FIR can better represent the data characteristics of Chart2014,reduce the calculation difficulty,and be more intuitive,and,the choice of different interpolation methods in FIR and the influence of the“exclusion radius R”parameter were discussed.FIR avoids complex calculations of spatial distances among points from different sources,and instead uses spatial exclusion map to perform one-step screening based on the exclusion radius R,which greatly improved the fusion status of a reliable dataset.The fusion results of different experiments were analyzed statistically with root mean square error and mean relative error,showing that the interpolation methods based on Delaunay triangulation are more suitable for the fusion of nautical chart depth of China,and factors such as the point density distribution of multiple source data,accuracy,interpolation method,and various terrain conditions should be fully considered when selecting the exclusion radius R.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102201,U2341244).
文摘An experimental and finite element simulation investigation are conducted to study the deformation patterns of steel targets during the penetration process of tungsten alloy long rods,as well as the influence of strength of the target on the deformation patterns.The experimental results revealed slight mass loss in the first layer of the steel target during the transient entrance phase,with an extremely negligible loss in target mass during the quasi-steady penetration phase.The results of macro-analysis,micro-analysis and simulation show that the eroded target material migrated towards the periphery of the crater,causing an increase in the target's thickness,remained within the target,instead of flowing out of the crater.Therefore,the process of long rods penetrating the metal target is considered as a process of backward extrusion.By combining the backward extrusion theory with energy conservation,a penetration depth model for long rods penetrating a metal target,taking into account both the diameter of the crater and the friction coefficient between the rod and the target,has been established.Although the model is not yet perfect,it innovatively applies the principles of solid mechanics to the study of long rod penetration.Additionally,it takes into account the friction coefficient between the rod and the target during the penetration process.Therefore,this model provides a new research direction for future studies on long rod penetration.
基金supported by the National Natural Science Foundation of China(No.22271131)the Department of Science and Technology in Jiangxi Province(No.20225BCJ23029).
文摘Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase transition have rarely been reported yet.Herein,we discovered ferroelasticity in a pair of organic enantiomers,(1S and/or 1R)-2,10-camphorsultam(S-and R-CPS),which undergoes a high-T_(c)plastic phase transition.Both large entropies change of∼45 J mol^(-1)K^(-1)and evidently ductile deformation process confirm the plastic phase feature.Strip-like ferroelastic domain patterns and bidirectional domain movements have been observed via polarized light microscopy and nanoindentation technique,respectively.This work highlights the discovery of organic ferroelastic combining the features of enantiomers and plastic phase transition,which contributes insights into exploration of organic multifunctional materials.
基金supported by the second batch of Bureaulevel Projects of the Xizang Medicine Administration of the Xizang Autonomous Region in 2020(No.JJKT20200024).
文摘Five meroterpenoids,rhodonoids K-M(1-2),daurichromene E(3),and grifolins A-B(4-5),together with seven known compounds(6-12),were isolated from Rhododendron anthopogonoides.The chemical structures of these compounds were elucidated through comprehensive analysis of high-resolution electrospray ionization mass spectrometry(HR-ESI-MS),ultraviolet(UV),infrared spectroscopy(IR),and nuclear magnetic resonance(NMR)data.Their absolute configurations were determined by comparing experimental electronic circular dichroism(ECD)spectra with computed values.Notably,compounds 1 and 3 demonstrated significant inhibitory effects on lipopolysaccharide(LPS)-induced inflammation in RAW264.7 cells.These compounds markedly suppressed the mRNA expressions of inflammatory factors,including interleukin(IL)-1β,IL-6,and tumor necrosis factor-α(TNF-α)while also down-regulating the protein expressions of inducible nitric oxide synthase(iNOS)and cyclooxygenase-2(COX-2).
基金Project supported by the National Natural Science Foundation of China (Grant No. 62075182)the National Key Research and Development Program of China (Grant No. 2022YFB3207502)。
文摘A multi-wavelength and transversely mode-switchable fiber laser based on a ring-core fiber Bragg grating(RCFBG) is proposed. Two RCFBGs with high and low reflectivity are inscribed using a femtosecond laser and the phase mask scanning technique, serving as the mirrors in an all-fiber laser linear resonator. Leveraging the polarization dependence of the RCFBG through side exposure, we can readily achieve switchable single-wavelength, dual-wavelength, or triple-wavelength laser outputs by adjusting the polarization controller(PC) inside the resonator. Additionally, three distinct modes, namely, cylindrical vector beam(CVB), fundamental and mixed modes, are successfully obtained in single-wavelength laser operation.Azimuthally or radially polarized lasers can be realized by tuning two PCs inside and outside the resonator while operating in CVB mode. This innovative multi-wavelength and transversely mode-switchable fiber laser based on RCFBGs holds significant potential for applications in wavelength division multiplexing and mode division multiplexing systems.
文摘By examining a specific case of compensating for nighttime construction noise in Beijing’s construction projects,we explored how the costs of mitigating construction noise disturbance could be fairly distributed among multiple construction projects near residential areas.In this process,the local government played a crucial coordinating role.According to regulations,construction units must include the costs of preventing and controlling construction noise pollution in the project cost.The construction contract should clearly specify the construction unit’s responsibility for noise pollution prevention and control.After signing the contract,the construction unit should promptly undertake relevant measures to minimize disturbances caused by nighttime construction,aiming to reduce the adverse impacts on the community and ensure the smooth progress of the construction project.
基金Supported by the PetroChina Science and Technology Project(2021DJ4002,2022DJ3908)。
文摘Acoustic reflection imaging logging technology can detect and evaluate the development of reflection anomalies,such as fractures,caves and faults,within a range of tens of meters from the wellbore,greatly expanding the application scope of well logging technology.This article reviews the development history of the technology and focuses on introducing key methods,software,and on-site applications of acoustic reflection imaging logging technology.Based on the analyses of major challenges faced by existing technologies,and in conjunction with the practical production requirements of oilfields,the further development directions of acoustic reflection imaging logging are proposed.Following the current approach that utilizes the reflection coefficients,derived from the computation of acoustic slowness and density,to perform seismic inversion constrained by well logging,the next frontier is to directly establish the forward and inverse relationships between the downhole measured reflection waves and the surface seismic reflection waves.It is essential to advance research in imaging of fractures within shale reservoirs,the assessment of hydraulic fracturing effectiveness,the study of geosteering while drilling,and the innovation in instruments of acoustic reflection imaging logging technology.
