Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of mate...Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of materials.A smart use of materials leads to reduced fuel consumption and lower operating costs,making them highly desirable for aircraft manufacturers.Furthermore,the customizable properties of lattice structures allow for tailoring to specific design requirements,leading to improved performance and safety for aircraft.These advantages make lattice structures an important focus for research and development in the aviation industry.This paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V,designed for use in an anti-ice system.The truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical properties.Results showed that lattice trusses exhibited high levels of compressive strength,making them suitable for use in applications where mechanical resistance and durability are critical,such as in anti-ice systems.We also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical properties.The study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems,as well as other areas where high strength-to-weight ratios are required.The results of this research contribute to the development of lightweight,efficient,and durable anti-ice systems for use in aviation and other industries.展开更多
In the present work,the hydrodynamic performance of the double deflector rectangular cambered otter board was studied using wind tunnel experiment,flume tank experiment and numerical simulation.Results showed that the...In the present work,the hydrodynamic performance of the double deflector rectangular cambered otter board was studied using wind tunnel experiment,flume tank experiment and numerical simulation.Results showed that the otter board had a good hydrodynamic performance with the maximum lift-to-drag ratio(K_(MAX) = 3.70).The flow separation occurred when the angle of attack(AOA) was at 45?,which revealed that the double deflector structure of the otter board can delay the flow separation.Numerical simulation results showed a good agreement with experiment ones,and could predict the critical AOA,which showed that it can be used to study the hydrodynamic performance of the otter board with the advantage of flow visualization.However,the drag coefficient in flume tank was much higher than that in wind tunnel,which resulted in a lower lift-to-drag ratio.These may be due to different fluid media between flume tank and wind tunnel,which result in the big difference of the vortexes around the otter board.Given the otter boards are operated in water,it was suggested to apply both flume tank experiment and numerical simulation to study the hydrodynamic performance of otter board.展开更多
In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulatin...In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio(AR) of 0.85 and a horizontal planform area( S) of 0.09 m^2. The results indicated that the critical angle( α_(cr)) of the model was 44°, whereas the maximum lift coefficient( C_(Lmax)) was up to 1.715, and the door efficiency( K) was 1.122. The attack angle( α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient( C_L) and door efficiency( K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle( α_(cr)) and maximum of lift coefficient( C_(Lmax)) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.展开更多
An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapt...An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapter board technology.Four layers of high-resistance silicon substrate stack packaging are implemented based on the wafer-level gold-gold bonding process.Each layer adopts though silicon via(TSV)technology to realize signal interconnection.A core monolithic integrated microwave chip(MMIC)is embedded in the silicon cavity,and the silicon-based filter is integrated with the high-resistance silicon substrate.The interconnect line,cavity and filter of the silicon-based adapter board are designed with AutoCAD,and HFSS is adopted for 3D electromagnetic field simulation.According to the measured results,the radio frequency(RF)of the mixing multi-function chip is 40-44 GHz and its intermediate frequency(IF)can cover the Ku band with a chip size of 10 mm×11 mm×1 mm.The multiplier multi-function chip operates at 16-20 GHz.The fundamental suppression is greater than 50 dB and the second harmonic suppression is better than 40 dB with a chip size of 8 mm×8 mm×1 mm.The cascaded fully assembled mixing component achieves a spur of better than-50 dBc and a gain of better than 15 dB.展开更多
At the background of the experience economy becoming major economic form in place of the service economy,forest experience develops vigorously and becomes a new approach for people alleviating pressure,acquiring knowl...At the background of the experience economy becoming major economic form in place of the service economy,forest experience develops vigorously and becomes a new approach for people alleviating pressure,acquiring knowledge,and relaxation. On the basis of analyzing concept and characteristics of the forest experience,this paper analyzed current situation of forest experience by taking Kunming West Mountain Forest Park as an example. It found there are existing problems in subject image,development methods and degree,professional personnel and concept. In view of these problems,it came up with recommendations including determining subject image,designing special products,accelerating cultivation of professional personnel,and strengthening training of forest experience concept. It is expected to provide reference for multi-functional use theory of China and provide ideas for developing forest experience projects.展开更多
文摘Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of materials.A smart use of materials leads to reduced fuel consumption and lower operating costs,making them highly desirable for aircraft manufacturers.Furthermore,the customizable properties of lattice structures allow for tailoring to specific design requirements,leading to improved performance and safety for aircraft.These advantages make lattice structures an important focus for research and development in the aviation industry.This paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V,designed for use in an anti-ice system.The truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical properties.Results showed that lattice trusses exhibited high levels of compressive strength,making them suitable for use in applications where mechanical resistance and durability are critical,such as in anti-ice systems.We also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical properties.The study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems,as well as other areas where high strength-to-weight ratios are required.The results of this research contribute to the development of lightweight,efficient,and durable anti-ice systems for use in aviation and other industries.
基金supported by the National Key Technology R&D Program(No.2013BAD13B03)the Key R&D Project from Science and Technology Department of Zhejiang Province(Nos.2018C02026,2018C02040)+1 种基金the National Natural Science Foundation of China(No.31072246)the Fundamental Research Funds for the Central Universities(No.201564020)
文摘In the present work,the hydrodynamic performance of the double deflector rectangular cambered otter board was studied using wind tunnel experiment,flume tank experiment and numerical simulation.Results showed that the otter board had a good hydrodynamic performance with the maximum lift-to-drag ratio(K_(MAX) = 3.70).The flow separation occurred when the angle of attack(AOA) was at 45?,which revealed that the double deflector structure of the otter board can delay the flow separation.Numerical simulation results showed a good agreement with experiment ones,and could predict the critical AOA,which showed that it can be used to study the hydrodynamic performance of the otter board with the advantage of flow visualization.However,the drag coefficient in flume tank was much higher than that in wind tunnel,which resulted in a lower lift-to-drag ratio.These may be due to different fluid media between flume tank and wind tunnel,which result in the big difference of the vortexes around the otter board.Given the otter boards are operated in water,it was suggested to apply both flume tank experiment and numerical simulation to study the hydrodynamic performance of otter board.
基金Supported by the Technological Research on Reforming Otter Boards of Bottom Trawl in Mauretania and Guinea(China National Fisheries Corporation,CNFC)Technological Research on Transformation and Upgrading of Shrimp Trawl in Sierra Leone(CNFC)Far Sea Fisheries Resources Monitoring and Assessment of South China Sea(No.2013050212)
文摘In this paper, we tested the hydrodynamic characteristics of a new, double-winged otter board that consists of a forewing, a leading edge slat and a trailing edge flap. Flume experiments were conducted in a circulating flume tank by using a model with an aspect ratio(AR) of 0.85 and a horizontal planform area( S) of 0.09 m^2. The results indicated that the critical angle( α_(cr)) of the model was 44°, whereas the maximum lift coefficient( C_(Lmax)) was up to 1.715, and the door efficiency( K) was 1.122. The attack angle( α) ranged from 30° to 48° and from 10° to 46° when the lift coefficient( C_L) and door efficiency( K) were greater than 1.2 and 1.0, respectively. To compare the difference between double-winged otter board and traditional Morgere Polyvalent Ovale, same model of Morgere Polyvalent Ovale was also tested under the same experimental conditions. The critical angle( α_(cr)) and maximum of lift coefficient( C_(Lmax)) of the doublewinged otter board were 37.5% and 14.6% larger than those of the Morgere Polyvalent Ovale. Therefore, we concluded that the novel, double-winged otter board was more suitable for bottom trawling fisheries in the deep water of the Mauretania Sea due to its better hydrodynamic characteristics and stability.
文摘An ultra-wideband mixing component cascaded by a mixing multi-function chip and a frequency multiplier multi-function chip was demonstrated and implemented using 3D heterogeneous integration based on the silicon adapter board technology.Four layers of high-resistance silicon substrate stack packaging are implemented based on the wafer-level gold-gold bonding process.Each layer adopts though silicon via(TSV)technology to realize signal interconnection.A core monolithic integrated microwave chip(MMIC)is embedded in the silicon cavity,and the silicon-based filter is integrated with the high-resistance silicon substrate.The interconnect line,cavity and filter of the silicon-based adapter board are designed with AutoCAD,and HFSS is adopted for 3D electromagnetic field simulation.According to the measured results,the radio frequency(RF)of the mixing multi-function chip is 40-44 GHz and its intermediate frequency(IF)can cover the Ku band with a chip size of 10 mm×11 mm×1 mm.The multiplier multi-function chip operates at 16-20 GHz.The fundamental suppression is greater than 50 dB and the second harmonic suppression is better than 40 dB with a chip size of 8 mm×8 mm×1 mm.The cascaded fully assembled mixing component achieves a spur of better than-50 dBc and a gain of better than 15 dB.
基金Supported by Scientific Research Foundation of Southwest Forestry University(C15025)
文摘At the background of the experience economy becoming major economic form in place of the service economy,forest experience develops vigorously and becomes a new approach for people alleviating pressure,acquiring knowledge,and relaxation. On the basis of analyzing concept and characteristics of the forest experience,this paper analyzed current situation of forest experience by taking Kunming West Mountain Forest Park as an example. It found there are existing problems in subject image,development methods and degree,professional personnel and concept. In view of these problems,it came up with recommendations including determining subject image,designing special products,accelerating cultivation of professional personnel,and strengthening training of forest experience concept. It is expected to provide reference for multi-functional use theory of China and provide ideas for developing forest experience projects.
