Li2O-Al2O3-SiO2 glass prepared from traditional melting and cooling process was investigated.The surface characteristic of LAS glass was studied by simulating tin bath with different temperature and time,and the effec...Li2O-Al2O3-SiO2 glass prepared from traditional melting and cooling process was investigated.The surface characteristic of LAS glass was studied by simulating tin bath with different temperature and time,and the effect of surface tension/viscosity ratio on flatting time was analyzed.The results demonstrated that LAS glass can polish effectively when polishing at 1 300 ℃ for 8 min,and the optimum flatting and polishing temperature was 1 250-1 300 ℃.展开更多
In order to improve the soil preparation quality,a wide puddling and flatting machine for paddy field was designed with the functionality of tillage,soil crushing,puddling,burying stubble and flatting in one-time oper...In order to improve the soil preparation quality,a wide puddling and flatting machine for paddy field was designed with the functionality of tillage,soil crushing,puddling,burying stubble and flatting in one-time operation,which can be equipped on tractors with high power.This study focused on the design and analysis of key components of the machine including puddling equipment,flat shovel and balance structure.Optimal results with field trials and response surface analysis showed that the machine can operate optimally when the working speed,puddling depth and angle of flat shovel were 1.05 km/h,16 cm and 31.30°,respectively.The surface flatness standard deviation was 3.7 cm,and slurry degree was 1.03 g/cm3.Field validation test results were consistent with the optimal parameters,which was able to meet agronomic requirements of mechanical planting in China.展开更多
The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behav...The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behavior of oxidation products in the alloy.It is found that within the experimental temperature range,the higher the deformation temperature,the better the plasticity of the oxidation products.It was observed that increasing the Mn content refines the grains,enhances the deformation ability of the oxidation products,and improves the flatness of the interfaces.Since(Fe,Mn)O has a similar crystal structure to FeO,the addition of Mn refines the grains of(Fe,Mn)O,causing the deformation to be distributed across more grains under the same deformation amount,and thereby improving its plasticity.At the interface between Fe-Mn alloy oxidation products and the matrix,there exists a spinel-phase solid solution,which can deform together with the oxidation products and the matrix at high temperatures.It was found that with increasing the Mn content,the size and number of pores between the spinel phases increased.First-principles simulation calculations were used to verify this,showing that Mn promotes the generation of vacancies.The greater number of pores in the spinel phase can effectively relieve the compressive stress caused by rolling deformation,thereby improving the deformation capability of the oxidation products at the interface.展开更多
Assessing the carbon sink potential of marine aquaculture is critical to fostering sustainable marine economic development and achieving carbon neutrality.This study evaluates the carbon sink potential of four nearsho...Assessing the carbon sink potential of marine aquaculture is critical to fostering sustainable marine economic development and achieving carbon neutrality.This study evaluates the carbon sink potential of four nearshore aquaculture systems in China:floating raft,net cage,pond,and tidal flat.China’s coastal aquaculture shows a dramatic potential range from−5401.28×10^(4)t to 84.65×10^(4)t,acting as both a carbon sink and a source.Floating raft(11.19×10^(4)t to 105.65×10^(4)t)and tidal flat(42.83×10^(4)t to 114.35×10^(4)t)are net carbon sinks.In contrast,net cage(−427.39×10^(4)t to−4.26×10^(4)t)and pond(−5027.91×10^(4)t to−131.09×10^(4)t)are significant net carbon sources.This heterogeneity is driven by differences in species,feed inputs,energy consumption,and management practices.The results highlight the need for targeted low-carbon technologies in high-emission systems to maximize carbon sequestration and mitigate their environmental impacts.This study provides a scientific basis for optimizing carbon management and offers insights for global sustainable aquaculture and carbon neutrality.展开更多
This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass ...This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass density of the FGM coating vary exponentially along the thickness direction.The FGM coating and the homogeneous half-plane possess viscoelastic properties,which are described by a linearly hysteretic damping model.By applying the asymptotic method and the Fourier integral transform technique,the contact problem is converted into a Cauchy singular integral equation.The effects of excitation frequency,gradient index,damping factor ratio,and punch width on the vertical impedance and dynamic contact stress are analyzed.The results indicate that adjusting the gradient index of the FGM coating can significantly affect the contact stress and vertical impedance.展开更多
The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based ca...The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based cathode La_(0.6)Sr_(0.4)CoO_(3)(LSC)offers excellent catalytic performance,its TEC is significantly larger than that of the electrolyte.In this study,we mechanically mix Sm_(0.2)Ce_(0.8)O_(2−δ)(SDC)with LSC to create a composite cathode.By incorporating 50wt%SDC,the TEC decreases significantly from 18.29×10^(−6) to 13.90×10^(−6) K^(−1).Under thermal-shock conditions ranging from room temperature to 800℃,the growth rate of polarization resistance is only 0.658%per cycle,i.e.,merely 49%that of pure LSC.The button cell comprising the LSC-SDC composite cathode operates stably for over 900 h without Sr segregation,with a voltage growth rate of 1.11%/kh.A commercial flat-tube cell(active area:70 cm^(2))compris-ing the LSC-SDC composite cathode delivers 54.8 W at 750℃.The distribution of relaxation-time shows that the non-electrode portion is the main rate-limiting step.This study demonstrates that the LSC-SDC mixture strategy effectively improves the compatibility with the electrolyte while maintaining a high output,thus rendering it a promising commercial cathode material.展开更多
Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-ze...Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-zero genus can generate ideal flat bands.However,experimental realization of such geometrically engineered systems is very difficult.In this work,we demonstrate that flat planes with strategically patterned hole defects can engineer ideal flat bands.We construct two families of models:singular flat band systems where degeneracy is stabilized by non-contractible loop excitations tied to hole defects and perfectly nested van Hove systems where degeneracy arises from line excitations in momentum space.These models circumvent the need for exotic manifolds while retaining the essential features of topological flat bands.By directly linking defect engineering to degeneracy mechanisms,our results establish a scalable framework for experimentally accessible flat band design.展开更多
With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Sa...With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.展开更多
In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were im...In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were impressed by sweet and juicy Jinshan flat peaches.Jinshan has a history of flat peach cultivation that spans hundreds of years dating back to the Yuan Dynasty(1271-1368).展开更多
Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,W...Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.展开更多
The Lieb lattice, characterized by its distinctive Dirac cone and flat-band electronic structures, hosts a variety of exotic physical phenomena. However, its realization remains largely confined to artificial lattices...The Lieb lattice, characterized by its distinctive Dirac cone and flat-band electronic structures, hosts a variety of exotic physical phenomena. However, its realization remains largely confined to artificial lattices. In this work, we propose the concept of a Lieb electride, where the non-bound electrons gather at the middle edges,behaving as the quasi-atoms of a Lieb lattice, enabling the emergence of flat bands. Using crystal structure prediction method MAGUS and first-principles calculations, we predict a stable candidate, Ca_(2)I, at ambient pressure. Distinct from conventional electrides with localized electrons at cavity centers, Ca_(2)I features interstitial electrons situated at cavity edges. The resultant flat bands lie close to the Fermi level, giving rise to a pronounced peak in the density of states and leading to Stoner-type ferromagnetism. With increasing pressures, we observe quantum phase transitions from ferromagnetic to non-magnetic and finally to antiferromagnetic orders in Ca_(2)I.Intriguingly, superconductivity emerges in the antiferromagnetic region, suggesting potential competition between these correlated states. Our study not only extends the concepts of electrides but also provides a novel strategy for realizing Lieb lattices through non-bound electrons. This work establishes Ca_(2)I as a promising platform for exploring flat-band physics and correlated electronic states, opening avenues for novel quantum phenomena in electride-based materials.展开更多
20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model...20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model for flatness in a 20-high mill is proposed based on a model coupling method capable of forecasting the flatness of cold-rolled stainless steel thin strips under symmetric and asymmetric rolling conditions.The model integrates deformation coordination equations between rolls,force and moment balance equations,strip exit transverse displacement equations,and no-load roll gap equations into a unified set of linear equations.This solution process avoids repeated iterations between the elastic deformation model of the roll system and the plastic deformation model of the strip,which is a limitation of the traditional method and significantly improves the calculation speed and stability.The accuracy of the model was verified via a ZR22B-52 Sendzimir 20-high mill.The measured and calculated flatness values highly coincided,confirming the model’s accuracy.Rolling calculations of 304 stainless steel thin strips demonstrate that the new model results are consistent with those of the traditional method.The calculation time of the new model is only approximately 0.04%-0.35%that of the traditional method.On this basis,the impact of common flatness control methods on the flatness has been analyzed.展开更多
GERON Card Clothing(Jiangsu)Co.,Ltd.was founded in 1987 and is a professional textile carding equipment enterprise integrating research,production and sales.The production and sales of carding equipment have been lead...GERON Card Clothing(Jiangsu)Co.,Ltd.was founded in 1987 and is a professional textile carding equipment enterprise integrating research,production and sales.The production and sales of carding equipment have been leading the industry for many years.Our products include metallic card clothing,flat-top,stationary flat,circular comb and combing roller.Our brands include TYRION,Blue Diamond,Diamond,Pioneer and Lance.We provide customers with the most advanced carding solutions.展开更多
In this paper,the optical efficiency and output thermal power of the heliostat mirror field are analyzed and optimized by constructing a geometric model and an optimization algorithm for the optimal design of the heli...In this paper,the optical efficiency and output thermal power of the heliostat mirror field are analyzed and optimized by constructing a geometric model and an optimization algorithm for the optimal design of the heliostat mirror field of a tower-type solar photovoltaic power plant.First,based on the solar position model and the optical efficiency model of the heliostat mirror field,the annual average optical efficiency,the annual average output thermal power,and the annual average output thermal power per unit mirror area of the heliostat mirror field are calculated.Secondly,the EB layout was used to optimize the heliostat field,and the parameters of heliostat size and mounting height were optimized by genetic algorithm and particle swarm algorithm to maximize the annual average output thermal power per unit mirror surface area.The results show that the optimized heliostat mirror field significantly increases the annual average output thermal power per unit mirror area under the condition of achieving the rated power,which provides theoretical basis and technical support for the design and operation of the tower solar thermal power plant.展开更多
This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic...This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic numerical simulations conducted on two real buildings located near Florence,Italy,and modeled in 130 different European locations,with a particular focus on the Mediterranean climate,it was possible to quantify the energy benefits derived from the application of green roofs on existing structures.The results show that,while the effect on heating is limited,with an average reduction in energy demand of only a few percentage points,the impact on cooling is significantly more pronounced,with average savings of 20%in non-renewable primary energy,particularly in Mediterranean climates with high CDD(cooling degree days)values.The study confirms that green roofs can be an effective solution to improve the energy efficiency of existing buildings with flat roofs in the Mediterranean climate,in line with European goals for reducing CO_(2) emissions and promoting renewable energy.展开更多
This study delves into both experimental and analytical examinations of heat exchange in a straight channel, where Al_(2)O_(3)-water nanofluids are utilized, spanning the Reynolds number spectrum from 100 to 1800. Div...This study delves into both experimental and analytical examinations of heat exchange in a straight channel, where Al_(2)O_(3)-water nanofluids are utilized, spanning the Reynolds number spectrum from 100 to 1800. Diverse volume fractions(1%, 2%, and 3%) of Al_(2)O_(3)-water nanofluids are meticulously prepared and analyzed. The essential physical properties of these nanofluids, critical for evaluating their thermal and flow characteristics, have been comprehensively assessed. From a quantitative perspective, numerical simulations are employed to predict the Nusselt number(Nu) and friction factor(f). The empirical findings reveal intriguing trends: the friction factor experiences an upward trend with diminishing velocity, attributed to heightened molecular cohesion. Conversely, the friction factor demonstrates a decline with diminishing volume fractions, a consequence of reduced particle size. Both the nanofluid's viscosity and heat transfer coefficient exhibit a rise in tandem with augmented volume flow rate and concentration gradient. Notably, the simulation results harmonize remarkably well with experimental data. Rigorous validation against prior studies underscores the robust consistency of these outcomes. In the pursuit of augmenting heat transfer, a volume fraction of 3% emerges as particularly influential, yielding an impressive 53.8% enhancement. Minor increments in the friction factor, while present, prove negligible and can be safely overlooked.展开更多
Understanding the characteristics of windsand flow field in the curve section of desert highway under different wind directions is helpful for reducing the wind-sand damage in the curve section.Therefore,taking the de...Understanding the characteristics of windsand flow field in the curve section of desert highway under different wind directions is helpful for reducing the wind-sand damage in the curve section.Therefore,taking the desert section of Wuma Expressway in Zhongwei city,Ningxia,China as the research background,the wind-sand flow field and sand accumulation phenomenon of concave surface plane curve embankment under different wind directions is calculated and analyzed by computational fluid dynamics(CFD)numerical simulation method.The results show that:(1)Under different wind directions,along the direction of the route,at the starting point of the route,the windward slope of the embankment is a circular arc section,which reduces the resistance of wind-sand flow and promotes the acceleration of sand particles.In the middle of the route,the low-speed area of the windward slope toe and the leeward slope toe is small;at the end of the route,the high-speed area on the shoulder side of the leeward road rises upward.(2)Under different wind directions,the smaller the angle between the wind direction and the route,the stronger the lateral transport effect on the wind-blown sand flow,and the more sand particles transported along the route direction.(3)Under different wind directions,in the concave windward horizontal curve,with the increase of the angle,the sand area on the top of the embankment shows an increasing trend.Whenα=30°,45°,60°,75°,the percentage of the sand area on the top of the embankment to the total embankment area is 0%,33.3%,64.4%,71.0%,respectively.(4)Under different wind directions,along the route direction,the sand transport efficiency of the concave surface upwind plane curve embankment shows a decreasing trend.In the case of a certain radius of the horizontal curve,the angle range between the wind direction and the concave horizontal curve route is recommended to be 30°-45°.展开更多
The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,tra...The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,traditional coolants are starting to fall short.Nanofluids,which involve tiny nanoparticles dispersed into standardcooling liquids,offer a new solution by significantly improving heat transfer capabilities.The article categorizesthe different types of nanofluids(ranging from those based on metals and metal oxides to carbon materials andhybrid combinations)and examines their effects on the improvement of radiator performance.General consensusexists in the literature that nanofluids can support better heat dissipation and enable accordingly the developmentof smaller and lighter radiators,which require less coolant and allow more compact vehicle designs.However,thisreview demonstrates that the use of nanofluids does not come without challenges.These include the long-termstability of these fluids and material compatibility issues.A critical discussion is therefore elaborated about thegaps to be filled and the steps to be undertaken to promote and standardize the use of these fluids in the industry.展开更多
基金Funded partly by the National Key Technology R&D Program in the 11th Five Year Plan of China(No. 2006BAJ02B00)Natural Science Foundation of Hubei Province (No.2008CDA037)
文摘Li2O-Al2O3-SiO2 glass prepared from traditional melting and cooling process was investigated.The surface characteristic of LAS glass was studied by simulating tin bath with different temperature and time,and the effect of surface tension/viscosity ratio on flatting time was analyzed.The results demonstrated that LAS glass can polish effectively when polishing at 1 300 ℃ for 8 min,and the optimum flatting and polishing temperature was 1 250-1 300 ℃.
基金the project funding of Science and Technology Bureau of Harbin(2010AA6AN016)the 59th Chinese Postdoctoral Science Foundation(2016M59068).
文摘In order to improve the soil preparation quality,a wide puddling and flatting machine for paddy field was designed with the functionality of tillage,soil crushing,puddling,burying stubble and flatting in one-time operation,which can be equipped on tractors with high power.This study focused on the design and analysis of key components of the machine including puddling equipment,flat shovel and balance structure.Optimal results with field trials and response surface analysis showed that the machine can operate optimally when the working speed,puddling depth and angle of flat shovel were 1.05 km/h,16 cm and 31.30°,respectively.The surface flatness standard deviation was 3.7 cm,and slurry degree was 1.03 g/cm3.Field validation test results were consistent with the optimal parameters,which was able to meet agronomic requirements of mechanical planting in China.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB3304800)the Reviving-Liaoning Excellence Plan(XLYC2203186).
文摘The high-temperature compressive deformation behavior of medium manganese steel using a four-roll reversible rolling mill is investigated,revealing the effects of different Mn contents on the thermal deformation behavior of oxidation products in the alloy.It is found that within the experimental temperature range,the higher the deformation temperature,the better the plasticity of the oxidation products.It was observed that increasing the Mn content refines the grains,enhances the deformation ability of the oxidation products,and improves the flatness of the interfaces.Since(Fe,Mn)O has a similar crystal structure to FeO,the addition of Mn refines the grains of(Fe,Mn)O,causing the deformation to be distributed across more grains under the same deformation amount,and thereby improving its plasticity.At the interface between Fe-Mn alloy oxidation products and the matrix,there exists a spinel-phase solid solution,which can deform together with the oxidation products and the matrix at high temperatures.It was found that with increasing the Mn content,the size and number of pores between the spinel phases increased.First-principles simulation calculations were used to verify this,showing that Mn promotes the generation of vacancies.The greater number of pores in the spinel phase can effectively relieve the compressive stress caused by rolling deformation,thereby improving the deformation capability of the oxidation products at the interface.
基金National Natural Science Foundation of China,No.42276231,No.41871112The Open Research Fund of the State Key Laboratory of Coastal and Marine Engineering,No.LP2518。
文摘Assessing the carbon sink potential of marine aquaculture is critical to fostering sustainable marine economic development and achieving carbon neutrality.This study evaluates the carbon sink potential of four nearshore aquaculture systems in China:floating raft,net cage,pond,and tidal flat.China’s coastal aquaculture shows a dramatic potential range from−5401.28×10^(4)t to 84.65×10^(4)t,acting as both a carbon sink and a source.Floating raft(11.19×10^(4)t to 105.65×10^(4)t)and tidal flat(42.83×10^(4)t to 114.35×10^(4)t)are net carbon sinks.In contrast,net cage(−427.39×10^(4)t to−4.26×10^(4)t)and pond(−5027.91×10^(4)t to−131.09×10^(4)t)are significant net carbon sources.This heterogeneity is driven by differences in species,feed inputs,energy consumption,and management practices.The results highlight the need for targeted low-carbon technologies in high-emission systems to maximize carbon sequestration and mitigate their environmental impacts.This study provides a scientific basis for optimizing carbon management and offers insights for global sustainable aquaculture and carbon neutrality.
基金Project supported by the National Natural Science Foundation of China(Nos.12021002,12192212,and 12462007)。
文摘This study explores the dynamic contact response of a viscoelastic functionally graded material(FGM)-coated half-plane under a rigid flat punch subjected to a time-harmonic vertical force.The elastic modulus and mass density of the FGM coating vary exponentially along the thickness direction.The FGM coating and the homogeneous half-plane possess viscoelastic properties,which are described by a linearly hysteretic damping model.By applying the asymptotic method and the Fourier integral transform technique,the contact problem is converted into a Cauchy singular integral equation.The effects of excitation frequency,gradient index,damping factor ratio,and punch width on the vertical impedance and dynamic contact stress are analyzed.The results indicate that adjusting the gradient index of the FGM coating can significantly affect the contact stress and vertical impedance.
基金the financial support from the National Natural Science Foundation of China(No.22209191)Ningbo Key R&D Project(No.2023Z155).
文摘The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based cathode La_(0.6)Sr_(0.4)CoO_(3)(LSC)offers excellent catalytic performance,its TEC is significantly larger than that of the electrolyte.In this study,we mechanically mix Sm_(0.2)Ce_(0.8)O_(2−δ)(SDC)with LSC to create a composite cathode.By incorporating 50wt%SDC,the TEC decreases significantly from 18.29×10^(−6) to 13.90×10^(−6) K^(−1).Under thermal-shock conditions ranging from room temperature to 800℃,the growth rate of polarization resistance is only 0.658%per cycle,i.e.,merely 49%that of pure LSC.The button cell comprising the LSC-SDC composite cathode operates stably for over 900 h without Sr segregation,with a voltage growth rate of 1.11%/kh.A commercial flat-tube cell(active area:70 cm^(2))compris-ing the LSC-SDC composite cathode delivers 54.8 W at 750℃.The distribution of relaxation-time shows that the non-electrode portion is the main rate-limiting step.This study demonstrates that the LSC-SDC mixture strategy effectively improves the compatibility with the electrolyte while maintaining a high output,thus rendering it a promising commercial cathode material.
基金supported by the Ministry of Science and Technology(Grant No.2022YFA1403901)the National Natural Science Foundation of China(Grant Nos.12494594,11888101,12174428,and 12504192)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)the New Cornerstone Investigator Program,the Chinese Academy of Sciences through the Youth Innovation Promotion Association(Grant No.2022YSBR-048)the Shanghai Science and Technology Innovation Action Plan(Grant No.24LZ1400800).
文摘Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-zero genus can generate ideal flat bands.However,experimental realization of such geometrically engineered systems is very difficult.In this work,we demonstrate that flat planes with strategically patterned hole defects can engineer ideal flat bands.We construct two families of models:singular flat band systems where degeneracy is stabilized by non-contractible loop excitations tied to hole defects and perfectly nested van Hove systems where degeneracy arises from line excitations in momentum space.These models circumvent the need for exotic manifolds while retaining the essential features of topological flat bands.By directly linking defect engineering to degeneracy mechanisms,our results establish a scalable framework for experimentally accessible flat band design.
文摘With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.
文摘In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were impressed by sweet and juicy Jinshan flat peaches.Jinshan has a history of flat peach cultivation that spans hundreds of years dating back to the Yuan Dynasty(1271-1368).
文摘Shaoxing Shuifu Reeds is professional on producing all kinds of Air Jet Reeds and Flat Reeds,which has an annual output of 90,000 meters air-jet reeds,300,000,000 pcs of profile dents and 60,000 meters of Flat Reeds,Which has been honored with China Air Jet Profile Reeds Research Center by China Textile Machinery Association in 2015.In order to reach the demands of high quality fabric and industrial textile products,the yarn is developing to high count,multicolor,various fibers,and the fabric is developing to high count,high density,environment protection.So we have researched out high density,multicolor,multinozzle,double energy saving type profile reeds to let you choose.
基金supported by the National Natural Science Foundation of China(Grant Nos.12125404,T2495231,123B2049,and 12204138)the National Key R&D Program of China(Grant No.2022YFA1403201)+7 种基金the Advanced MaterialsNational Science and Technology Major Project (Grant No.2024ZD0607000)the Basic Research Program of Jiangsu (Grant Nos.BK20233001 and BK20241253)the Jiangsu Funding Program for Excellent Postdoctoral Talent (Grant Nos.2024ZB002,2024ZB075,2025ZB440 and2025ZB852)the China Postdoctoral Science Foundation (Grant No.2025M773331)the Postdoctoral Fellowship Program of CPSF (Grant No.GZC20240695 and GZC20252202)the AI&AI for Science Program of Nanjing UniversityArtificial Intelligence and Quantum physics (AIQ) program of Nanjing Universitythe Fundamental Research Funds for the Central Universities。
文摘The Lieb lattice, characterized by its distinctive Dirac cone and flat-band electronic structures, hosts a variety of exotic physical phenomena. However, its realization remains largely confined to artificial lattices. In this work, we propose the concept of a Lieb electride, where the non-bound electrons gather at the middle edges,behaving as the quasi-atoms of a Lieb lattice, enabling the emergence of flat bands. Using crystal structure prediction method MAGUS and first-principles calculations, we predict a stable candidate, Ca_(2)I, at ambient pressure. Distinct from conventional electrides with localized electrons at cavity centers, Ca_(2)I features interstitial electrons situated at cavity edges. The resultant flat bands lie close to the Fermi level, giving rise to a pronounced peak in the density of states and leading to Stoner-type ferromagnetism. With increasing pressures, we observe quantum phase transitions from ferromagnetic to non-magnetic and finally to antiferromagnetic orders in Ca_(2)I.Intriguingly, superconductivity emerges in the antiferromagnetic region, suggesting potential competition between these correlated states. Our study not only extends the concepts of electrides but also provides a novel strategy for realizing Lieb lattices through non-bound electrons. This work establishes Ca_(2)I as a promising platform for exploring flat-band physics and correlated electronic states, opening avenues for novel quantum phenomena in electride-based materials.
基金supported by the National Natural Science Foundation of China(No.U21A20118)the Natural Science Foundation of Hebei Province(No.E2023203065)the National Key Laboratory of Metal Forming Technology and Heavy Equipment,China National Heavy Machinery Research Institute Co.,Ltd.(No.S2208100.W04).Author infor。
文摘20-high mills often face various flatness problems in the production of cold-rolled stainless steel thin strips.The flatness prediction model is essential for flatness control techniques.A novel rapid prediction model for flatness in a 20-high mill is proposed based on a model coupling method capable of forecasting the flatness of cold-rolled stainless steel thin strips under symmetric and asymmetric rolling conditions.The model integrates deformation coordination equations between rolls,force and moment balance equations,strip exit transverse displacement equations,and no-load roll gap equations into a unified set of linear equations.This solution process avoids repeated iterations between the elastic deformation model of the roll system and the plastic deformation model of the strip,which is a limitation of the traditional method and significantly improves the calculation speed and stability.The accuracy of the model was verified via a ZR22B-52 Sendzimir 20-high mill.The measured and calculated flatness values highly coincided,confirming the model’s accuracy.Rolling calculations of 304 stainless steel thin strips demonstrate that the new model results are consistent with those of the traditional method.The calculation time of the new model is only approximately 0.04%-0.35%that of the traditional method.On this basis,the impact of common flatness control methods on the flatness has been analyzed.
文摘GERON Card Clothing(Jiangsu)Co.,Ltd.was founded in 1987 and is a professional textile carding equipment enterprise integrating research,production and sales.The production and sales of carding equipment have been leading the industry for many years.Our products include metallic card clothing,flat-top,stationary flat,circular comb and combing roller.Our brands include TYRION,Blue Diamond,Diamond,Pioneer and Lance.We provide customers with the most advanced carding solutions.
基金supported in part by the University-Industry Collaborative Education Program under Grant 241006627080140.
文摘In this paper,the optical efficiency and output thermal power of the heliostat mirror field are analyzed and optimized by constructing a geometric model and an optimization algorithm for the optimal design of the heliostat mirror field of a tower-type solar photovoltaic power plant.First,based on the solar position model and the optical efficiency model of the heliostat mirror field,the annual average optical efficiency,the annual average output thermal power,and the annual average output thermal power per unit mirror area of the heliostat mirror field are calculated.Secondly,the EB layout was used to optimize the heliostat field,and the parameters of heliostat size and mounting height were optimized by genetic algorithm and particle swarm algorithm to maximize the annual average output thermal power per unit mirror surface area.The results show that the optimized heliostat mirror field significantly increases the annual average output thermal power per unit mirror area under the condition of achieving the rated power,which provides theoretical basis and technical support for the design and operation of the tower solar thermal power plant.
文摘This study analyzes the energy impact of applying green roofs on flat roofs of existing buildings,assessing their potential to reduce the demand for non-renewable primary energy for heating and cooling.Through dynamic numerical simulations conducted on two real buildings located near Florence,Italy,and modeled in 130 different European locations,with a particular focus on the Mediterranean climate,it was possible to quantify the energy benefits derived from the application of green roofs on existing structures.The results show that,while the effect on heating is limited,with an average reduction in energy demand of only a few percentage points,the impact on cooling is significantly more pronounced,with average savings of 20%in non-renewable primary energy,particularly in Mediterranean climates with high CDD(cooling degree days)values.The study confirms that green roofs can be an effective solution to improve the energy efficiency of existing buildings with flat roofs in the Mediterranean climate,in line with European goals for reducing CO_(2) emissions and promoting renewable energy.
文摘This study delves into both experimental and analytical examinations of heat exchange in a straight channel, where Al_(2)O_(3)-water nanofluids are utilized, spanning the Reynolds number spectrum from 100 to 1800. Diverse volume fractions(1%, 2%, and 3%) of Al_(2)O_(3)-water nanofluids are meticulously prepared and analyzed. The essential physical properties of these nanofluids, critical for evaluating their thermal and flow characteristics, have been comprehensively assessed. From a quantitative perspective, numerical simulations are employed to predict the Nusselt number(Nu) and friction factor(f). The empirical findings reveal intriguing trends: the friction factor experiences an upward trend with diminishing velocity, attributed to heightened molecular cohesion. Conversely, the friction factor demonstrates a decline with diminishing volume fractions, a consequence of reduced particle size. Both the nanofluid's viscosity and heat transfer coefficient exhibit a rise in tandem with augmented volume flow rate and concentration gradient. Notably, the simulation results harmonize remarkably well with experimental data. Rigorous validation against prior studies underscores the robust consistency of these outcomes. In the pursuit of augmenting heat transfer, a volume fraction of 3% emerges as particularly influential, yielding an impressive 53.8% enhancement. Minor increments in the friction factor, while present, prove negligible and can be safely overlooked.
基金supported by the National Natural Science Foundation of China“Study on the failure mechanism and evaluation method of sand control measures for railway machinery in sandy areas”(12302511)。
文摘Understanding the characteristics of windsand flow field in the curve section of desert highway under different wind directions is helpful for reducing the wind-sand damage in the curve section.Therefore,taking the desert section of Wuma Expressway in Zhongwei city,Ningxia,China as the research background,the wind-sand flow field and sand accumulation phenomenon of concave surface plane curve embankment under different wind directions is calculated and analyzed by computational fluid dynamics(CFD)numerical simulation method.The results show that:(1)Under different wind directions,along the direction of the route,at the starting point of the route,the windward slope of the embankment is a circular arc section,which reduces the resistance of wind-sand flow and promotes the acceleration of sand particles.In the middle of the route,the low-speed area of the windward slope toe and the leeward slope toe is small;at the end of the route,the high-speed area on the shoulder side of the leeward road rises upward.(2)Under different wind directions,the smaller the angle between the wind direction and the route,the stronger the lateral transport effect on the wind-blown sand flow,and the more sand particles transported along the route direction.(3)Under different wind directions,in the concave windward horizontal curve,with the increase of the angle,the sand area on the top of the embankment shows an increasing trend.Whenα=30°,45°,60°,75°,the percentage of the sand area on the top of the embankment to the total embankment area is 0%,33.3%,64.4%,71.0%,respectively.(4)Under different wind directions,along the route direction,the sand transport efficiency of the concave surface upwind plane curve embankment shows a decreasing trend.In the case of a certain radius of the horizontal curve,the angle range between the wind direction and the concave horizontal curve route is recommended to be 30°-45°.
文摘The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,traditional coolants are starting to fall short.Nanofluids,which involve tiny nanoparticles dispersed into standardcooling liquids,offer a new solution by significantly improving heat transfer capabilities.The article categorizesthe different types of nanofluids(ranging from those based on metals and metal oxides to carbon materials andhybrid combinations)and examines their effects on the improvement of radiator performance.General consensusexists in the literature that nanofluids can support better heat dissipation and enable accordingly the developmentof smaller and lighter radiators,which require less coolant and allow more compact vehicle designs.However,thisreview demonstrates that the use of nanofluids does not come without challenges.These include the long-termstability of these fluids and material compatibility issues.A critical discussion is therefore elaborated about thegaps to be filled and the steps to be undertaken to promote and standardize the use of these fluids in the industry.
