As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric material.Despite extensive research on the thermo...As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric material.Despite extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 Sci.China Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are studied.The results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁N-ASNSNR(N is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of L-SNSGNR are larger than those of L-SNS-Au.Further calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in L-SNS-GNR at room temperature,and over 4 in L-SNS-Au and 2.6 in L-SNS-GNR at 500 K.展开更多
Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experim...Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons. FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.展开更多
A set of stacked ribbons with the composition of Fe77Ga23 were prepared with different wheel velocities of 7 m/s, 12.5 m/s and 25 m/s（named as S7, S12.5 and S25, respectively）. High resolution X-ray diffraction patt...A set of stacked ribbons with the composition of Fe77Ga23 were prepared with different wheel velocities of 7 m/s, 12.5 m/s and 25 m/s（named as S7, S12.5 and S25, respectively）. High resolution X-ray diffraction patterns of these ribbons show that all the ribbons present the disordered A2 structure, whereas an additional modified-DO3 phase is detected in S12.5 and S25. S25 has stronger（100） texture than other two samples. Ga K-edge extended X-ray absorption fine structure results indicate that both bond distance and the number of Ga atoms in the second neighbor shell around Ga decrease with increasing wheel velocity. No Ga cluster is detected in the studied ribbons. A short-range ordering Ga-rich phase and large local strain have no obvious influence on magnetostriction of S7. It is believed that both the（100） texture and the additional modified-DO3 phase play a positive role in magnetostrictive properties of Fe77Ga23 ribbons.展开更多
The aim of this study is to analyze the ecological ideas of local habitat conservation,least intervention and concise ecological design in the design of Red Ribbon Park,and meanwhile put forward the suggestion that th...The aim of this study is to analyze the ecological ideas of local habitat conservation,least intervention and concise ecological design in the design of Red Ribbon Park,and meanwhile put forward the suggestion that the ecosystem health level of Tanghe River should be promoted as a whole.展开更多
Using the multiple reference frames （MRF） impeller method, the three-dimensional non-Newtonian flow field generated by a double helical ribbon （DHR） impeller has been simulated. The velocity field calculated by th...Using the multiple reference frames （MRF） impeller method, the three-dimensional non-Newtonian flow field generated by a double helical ribbon （DHR） impeller has been simulated. The velocity field calculated by the numerical simulation was similar to the previous studies and the power constant agreed well with the experimental data. Three computational fluid dynamic （CFD） methods, labeled Ⅰ, Ⅱ and Ⅲ, were used to compute the Metzuer constant k5. The results showed that the calculated value from the slop method （method Ⅰ） was consistent with the experimental data. Method Ⅱ, which took the maximal circumference-average shear rate around the impeller as the effective shear rate to compute ks, also showed good agreement with the experiment. However, both methods suffer from the complexity of calculation procedures. A new method （method Ⅲ） was devised in this paper to use the area-weighted average viscosity around the impeller as the effective viscosity for calculating k5. Method Ⅲ showed both good accuracy and ease of use.展开更多
To resolve the path tracking problem of autonomous ground vehicles,an analysis of existing path tracking methods was carried out and an important conclusion was got.The vehicle-road model is crucial for path following...To resolve the path tracking problem of autonomous ground vehicles,an analysis of existing path tracking methods was carried out and an important conclusion was got.The vehicle-road model is crucial for path following.Based on the conclusion,a new vehicle-road model named "ribbon model" was constructed with consideration of road width and vehicle geometry structure.A new vehicle-road evaluation algorithm was proposed based on this model,and a new path tracking controller including a steering controller and a speed controller was designed.The difficulties of preview distance selection and parameters tuning with speed in the pure following controller are avoided in this controller.To verify the performance of the novel method,simulation and real vehicle experiments were carried out.Experimental results show that the path tracking controller can keep the vehicle in the road running as fast as possible,so it can adjust the control strategy,such as safety,amenity,and rapidity criteria autonomously according to the road situation.This is important for the controller to adapt to different kinds of environments,and can improve the performance of autonomous ground vehicles significantly.展开更多
Let G be a discrete group with a neutral element and H be a quasitriangular Hopf G-coalgebra over a field k. Then the relationship between G-grouplike elements and ribbon elements of H is considered. First, a list of ...Let G be a discrete group with a neutral element and H be a quasitriangular Hopf G-coalgebra over a field k. Then the relationship between G-grouplike elements and ribbon elements of H is considered. First, a list of useful properties of a quasitriangular Hopf G-coalgebra and its Drinfeld elements are proved. Secondly, motivated by the relationship between the grouplike and ribbon elements of a quasitriangular Hopf algebra, a special kind of G-grouplike elements of H is defined. Finally, using the Drinfeld elements, a one-to-one correspondence between the special G-grouplike elements defined above and ribbon elements is obtained.展开更多
The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties...The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties and cryogenic magneto-caloric performances of the Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons.It is found that the ribbons reveal a second-order phase transition and are accompanied by a table-shaped magneto-caloric effect.The calculated magneticentropy-change maximum |ΔSM|,temperature averaged entropy change(i.e.,TEC(10)),and refrigerant capacity reach 13.9 J/kg·K,13.84 J/kg-K and 740 J/kg with magnetic field change of 0-7 T,respectively,indicating that the present Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons are good candidates for magnetic cooling.展开更多
2D carbon ribbon/Al_(2)O_(3) was synthesized with two-dimensional metal organic frameworks 2D-MOFs as precursors using the solvothermal and calcination methods.Batch experiments of adsorption parameters such as pH,liq...2D carbon ribbon/Al_(2)O_(3) was synthesized with two-dimensional metal organic frameworks 2D-MOFs as precursors using the solvothermal and calcination methods.Batch experiments of adsorption parameters such as pH,liquid/solid ratio,adsorption kinetics,adsorption thermodynamics,and anions competitions were investigated to understand the adsorptive behavior of fluoride on carbon ribbon/Al_(2)O_(3) and nitrogen-doped carbon ribbon/Al_(2)O_(3).The adsorption of fluoride on carbon ribbon/Al_(2)O_(3) could be described as the chemical and multilayer adsorption,while the adsorption of fluoride on nitrogen-doped carbon ribbon/Al_(2)O_(3) followed the chemical and monolayer adsorption phenomenon.The fluoride on nitrogen-doped carbon ribbon/Al_(2)O_(3) had a much faster adsorption rate of 3.1×10^(−7) m/s than carbon ribbon/Al_(2)O_(3),which was 1.2×10^(−7) m/s.The nitrogen-doping on carbon ribbon enhances structural defects and improves the adsorption performance of fluoride.Also,the diacetylene linkages(—C≡C—)and pyridinic-N were studied to understand their influences on removing fluoride.The result indicates that carbon ribbon and nitrogen-doped ribbon could serve as good adsorbents for removing fluoride.展开更多
A mathematical model of a ribbon pontoon bridge subjected to moving loads was formulated using the theory of simply supported beams.Two types of moving load models were used, the first a moving-constant-force model an...A mathematical model of a ribbon pontoon bridge subjected to moving loads was formulated using the theory of simply supported beams.Two types of moving load models were used, the first a moving-constant-force model and the second a moving-mass model.Using both types of loads, the dynamic behavior of a ribbon pontoon bridge was simulated while subjected to a single moving load and then multiple moving loads.Modeling was done with the Simulink package in MATLAB software.Results indicated that the model is correct.The two types of moving load models made little difference to the response ranges when loads moved on the bridge, but made some difference to the response phases.When loads left, the amplitude of the dynamic responses induced by the moving-constant-force model load were larger than those induced by the moving-mass model.There was a great deal more difference when there were more loads.展开更多
Amorphous （Nd,Pr）13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isoth...Amorphous （Nd,Pr）13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.展开更多
基金supported by the key projects of Hunan Provincial Department of Education(Grant No.21A0167)the Hunan Provincial Natural Science Foundation of China(Grant No.2019JJ40532)+1 种基金the National Natural Science Foundation of China(Grant Nos.11704417,11974106,and 11247030)the Talent Introducing Foundation of Central South University of Forestry and Technology(Grant No.104-0160)。
文摘As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric material.Despite extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 Sci.China Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are studied.The results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁N-ASNSNR(N is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of L-SNSGNR are larger than those of L-SNS-Au.Further calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in L-SNS-GNR at room temperature,and over 4 in L-SNS-Au and 2.6 in L-SNS-GNR at 500 K.
文摘Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons. FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.
基金Projects(11079022,51271093,10904071,U1332106)supported by the National Natural Science Foundation of China
文摘A set of stacked ribbons with the composition of Fe77Ga23 were prepared with different wheel velocities of 7 m/s, 12.5 m/s and 25 m/s（named as S7, S12.5 and S25, respectively）. High resolution X-ray diffraction patterns of these ribbons show that all the ribbons present the disordered A2 structure, whereas an additional modified-DO3 phase is detected in S12.5 and S25. S25 has stronger（100） texture than other two samples. Ga K-edge extended X-ray absorption fine structure results indicate that both bond distance and the number of Ga atoms in the second neighbor shell around Ga decrease with increasing wheel velocity. No Ga cluster is detected in the studied ribbons. A short-range ordering Ga-rich phase and large local strain have no obvious influence on magnetostriction of S7. It is believed that both the（100） texture and the additional modified-DO3 phase play a positive role in magnetostrictive properties of Fe77Ga23 ribbons.
文摘The aim of this study is to analyze the ecological ideas of local habitat conservation,least intervention and concise ecological design in the design of Red Ribbon Park,and meanwhile put forward the suggestion that the ecosystem health level of Tanghe River should be promoted as a whole.
基金Supported by the Natural Science Foundation of Tianjin （07JCZDJC02600）.
文摘Using the multiple reference frames （MRF） impeller method, the three-dimensional non-Newtonian flow field generated by a double helical ribbon （DHR） impeller has been simulated. The velocity field calculated by the numerical simulation was similar to the previous studies and the power constant agreed well with the experimental data. Three computational fluid dynamic （CFD） methods, labeled Ⅰ, Ⅱ and Ⅲ, were used to compute the Metzuer constant k5. The results showed that the calculated value from the slop method （method Ⅰ） was consistent with the experimental data. Method Ⅱ, which took the maximal circumference-average shear rate around the impeller as the effective shear rate to compute ks, also showed good agreement with the experiment. However, both methods suffer from the complexity of calculation procedures. A new method （method Ⅲ） was devised in this paper to use the area-weighted average viscosity around the impeller as the effective viscosity for calculating k5. Method Ⅲ showed both good accuracy and ease of use.
基金Project(90820302)supported by the National Natural Science Foundation of China
文摘To resolve the path tracking problem of autonomous ground vehicles,an analysis of existing path tracking methods was carried out and an important conclusion was got.The vehicle-road model is crucial for path following.Based on the conclusion,a new vehicle-road model named "ribbon model" was constructed with consideration of road width and vehicle geometry structure.A new vehicle-road evaluation algorithm was proposed based on this model,and a new path tracking controller including a steering controller and a speed controller was designed.The difficulties of preview distance selection and parameters tuning with speed in the pure following controller are avoided in this controller.To verify the performance of the novel method,simulation and real vehicle experiments were carried out.Experimental results show that the path tracking controller can keep the vehicle in the road running as fast as possible,so it can adjust the control strategy,such as safety,amenity,and rapidity criteria autonomously according to the road situation.This is important for the controller to adapt to different kinds of environments,and can improve the performance of autonomous ground vehicles significantly.
基金The National Natural Science Foundation of China(No.11371088)the Natural Science Foundation of Jiangsu Province(No.BK2012736)the Fundamental Research Funds for the Central Universities(No.KYZZ0060)
文摘Let G be a discrete group with a neutral element and H be a quasitriangular Hopf G-coalgebra over a field k. Then the relationship between G-grouplike elements and ribbon elements of H is considered. First, a list of useful properties of a quasitriangular Hopf G-coalgebra and its Drinfeld elements are proved. Secondly, motivated by the relationship between the grouplike and ribbon elements of a quasitriangular Hopf algebra, a special kind of G-grouplike elements of H is defined. Finally, using the Drinfeld elements, a one-to-one correspondence between the special G-grouplike elements defined above and ribbon elements is obtained.
基金Project supported by the National Natural Science Foundation of China(Grant No.52071197)the Science and Technology Committee of Shanghai(Grant No.19ZR1418300)+2 种基金the Independent Research and Development Project of State Key Laboratory of Advanced Special SteelShanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(Grant No.SKLASS 2019-Z003)the Science and Technology Commission of Shanghai Municipality(Grant No.19DZ2270200)。
文摘The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties and cryogenic magneto-caloric performances of the Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons.It is found that the ribbons reveal a second-order phase transition and are accompanied by a table-shaped magneto-caloric effect.The calculated magneticentropy-change maximum |ΔSM|,temperature averaged entropy change(i.e.,TEC(10)),and refrigerant capacity reach 13.9 J/kg·K,13.84 J/kg-K and 740 J/kg with magnetic field change of 0-7 T,respectively,indicating that the present Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons are good candidates for magnetic cooling.
基金the financial supports from the Key R&D Program of Hunan Province,China(No.2018SK2026)the National Key R&D Program of China(No.2018YFC1802204)the National Natural Science Foundation of China(No.51634010).
文摘2D carbon ribbon/Al_(2)O_(3) was synthesized with two-dimensional metal organic frameworks 2D-MOFs as precursors using the solvothermal and calcination methods.Batch experiments of adsorption parameters such as pH,liquid/solid ratio,adsorption kinetics,adsorption thermodynamics,and anions competitions were investigated to understand the adsorptive behavior of fluoride on carbon ribbon/Al_(2)O_(3) and nitrogen-doped carbon ribbon/Al_(2)O_(3).The adsorption of fluoride on carbon ribbon/Al_(2)O_(3) could be described as the chemical and multilayer adsorption,while the adsorption of fluoride on nitrogen-doped carbon ribbon/Al_(2)O_(3) followed the chemical and monolayer adsorption phenomenon.The fluoride on nitrogen-doped carbon ribbon/Al_(2)O_(3) had a much faster adsorption rate of 3.1×10^(−7) m/s than carbon ribbon/Al_(2)O_(3),which was 1.2×10^(−7) m/s.The nitrogen-doping on carbon ribbon enhances structural defects and improves the adsorption performance of fluoride.Also,the diacetylene linkages(—C≡C—)and pyridinic-N were studied to understand their influences on removing fluoride.The result indicates that carbon ribbon and nitrogen-doped ribbon could serve as good adsorbents for removing fluoride.
文摘A mathematical model of a ribbon pontoon bridge subjected to moving loads was formulated using the theory of simply supported beams.Two types of moving load models were used, the first a moving-constant-force model and the second a moving-mass model.Using both types of loads, the dynamic behavior of a ribbon pontoon bridge was simulated while subjected to a single moving load and then multiple moving loads.Modeling was done with the Simulink package in MATLAB software.Results indicated that the model is correct.The two types of moving load models made little difference to the response ranges when loads moved on the bridge, but made some difference to the response phases.When loads left, the amplitude of the dynamic responses induced by the moving-constant-force model load were larger than those induced by the moving-mass model.There was a great deal more difference when there were more loads.
基金supported by the National Natural Science Foundation of China (No. 50744014)the National Basic Research Foundation (No. 2004CCA04000)+3 种基金Science and Technology Department of Zhejiang Province (Nos. 2008C21046 and 2008C11086-1)the Natural Science Foundation of Zhejiang Province,China (No. Y406389)the Research and Development Program of Ningbo Bureau of Science and Technology (No. 2006B100054)K.C.Wong Magna Found in Ningbo University
文摘Amorphous （Nd,Pr）13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.
