中国科学院机构知识库网格系统: 检索

The Devil is in Details: Delving Into Lite FFN Design for Vision Transformers 会议论文 OAI收割
Seoul, Korea, 2024-4-14
作者: Chen, Zhiyang; Zhu, Yousong; Li, Zhaowen; Yang, Fan; Zhao, Chaoyang

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收藏 | 浏览/下载：27/0 | 提交时间：2024/05/28

Vision Transformer Light-Weight Structure Feed-Forward Networks

Wear Mechanism of Iron-based Alloy Coating by Arc Spraying 期刊论文 OAI收割
JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL, 2016, 卷号: 23, 期号: 8, 页码: 834-841
作者: Li Zengrong; Li Deyuan; Zhang Nannan; Huang He; Wang Xin

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收藏 | 浏览/下载：21/0 | 提交时间：2021/02/02

CARBIDE-FORMING ELEMENTS CHROMIUM CAST-IRON STEEL BEHAVIOR GLASS iron-based coating pore structure wear resistance engine cylinder block light weight

Study on ultra-light secondary baffle for coaxial two-mirror telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Zhang L.

收藏 | 浏览/下载：68/0 | 提交时间：2013/03/25

The coaxial two-mirror telescope consists of two mirrors facing each other. Classical two-mirror arrangements are Gregorian and Cassegrain. These systems are usually applied to space telescopes and often have optical baffles to prevent stray light from entering the focal plane. The optical baffles consist of concentric rings suspended between the secondary and the primary mirror. The secondary baffle for a large two-mirror optical system is designed and analyzed in this paper. According to mission of a telescope the structure should have high stiffness and high reliability and light weight. Compared with invar aluminum alloy and titanium alloy carbon fiber composite is currently the best material in terms of weight-to-strength ratio. It also has advantages of high temperature tolerance and low thermal expansion. So carbon fiber composite is chosen as material to meet requirements of the coaxial telescope. In this paper optimization method based on finite element analysis (FEA) is used for design the secondary baffle. Minimum weight of the baffle is chosen as an objective function. Thicknesses of former tube and vanes are chosen as variables. Analysis results show that the designed secondary baffle has maximum diameter of 180mm total length of 120mm and weighs 142g. And its fundamental frequency reaches 651Hz. Therefore the baffle has many advantages such as ultra-light weight high stiffness and dimensional stability etc. The optimization method and the baffle design can be helpful to other coaxial telescopes such as Cassegrain Gregorian and their subdivisions. 2012 IEEE.

Application of carbon fibre reinforced plastic for optical camera structure (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
An Y.; Yao J.-S.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Optical camera is a high-precision optical instrument and the optical lens must be always stable under various environments so the structural materials of optical camera should have good stability and machining performance characteristics. Generally the weight of the camera increases with the increasing size of optical camera aperture. The application of carbon fibre reinforced plastic(CFRP) in optical camera can help to improve the situation and meet the requirements of large volume and light weight. In this paper the properties of several kind of materials used in camera structure were compared the advantages of CFRP used in optical camera were analyzed the CFRP application profiles of domestic and international were introduced and the reason of gap was pointed out. There is a conclusion that CFRP will be widely used in the optical camera in China. 2012 IEEE.

The structure design and analysis of predigest laser combine bind and extend bind flat roof (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Advanced Engineering Materials and Technology, AEMT 2011, July 29, 2011 - July 31, 2011, Sanya, China
作者: Wang B.; Wang H.; Wang H.; Wang H.; Wang H.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

This paper put forward a kind of predigest laser combine bind and extend bind flat roof structure which is founded as fission flat roof and can be built in an little room 1280mm990mm815mm. This flat roof space location can be adjusted. This kind of seat can ensure the system complete laser combine and close as high precision. In this paper we designed the laser combine and close whole structure and install design. At last we did some finite statics analysis to some important parts. This design can ensure every laser fire directional adjust mete lower 30' and the flat roof quality is 770kg. The transition benchmark flat roof system most meet and emergency is 0.005mm at the premise of bear the weight of turn flat laden. It can be seen that this structure can satisfy the request of many lasers small space laser extend bind and adjust. This kind can be extended to other light combine bind and extend bind structure design. (2011) Trans Tech Publications Switzerland.

Structure optimization of strap-down inertial navigation system support (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Wang J.; Sun H.; Sun H.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

In order to meet the requirement of inertial navigation components and minimizing the system's weight and topological optimization was conducted. Then topological optimization and size optimization were conducted under conditions of random vibration and impact. Firstly according to the dynamic characteristics of missile and requirement of inertial navigation system the structure of inertial navigation support was designed according to types of missile connection and space arrangement of electronic components the method of transforming multi-loading cases to multi-loading constraints was used to optimizing the size of the support under conditions of random vibration and impact. Comparing to the original support structures RMS accelerations in installed points reduced by 25.2% under random vibration the weight of optimal structures reduced by 28.1% the structures also met the requirement of inertial navigation system under condition of impact. The support structure shows improvements in both dynamic characteristic and light weight comparing with the original one. 2011 IEEE.

High accuracy star image locating and imaging calibration for star sensor technology (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy light weight without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude star image locating star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors such as spherical aberration or coma aberration also have negative effect on the accuracy of star image locating of which the effect is necessarily reduced as well. At the beginning of this article the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically which are traditional centroid method Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second. 2010 SPIE.

Optimal design of strap-down inertial navigation support under random loads (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE International Conference on Information and Automation, ICIA 2010, June 20, 2010 - June 23, 2010, Harbin, Heilongjiang, China
作者: Li M.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

In order to realize miniaturization and light weight of the strap-down inertial navigation system and then to make sure that it works well under random loads optimal design is applied to the strap-down inertial navigation support with the methods of topology optimization and size optimization. Firstly based on the installation requirement of devices and connection requirement of the support and the carrier the initial structure of the support is designed. Topology optimization with FEA software ANSYS is adopted on the initial structure to get the basic one. Then 5 critical sizes are chosen as design variables and the support structure is optimized by means of size optimization to reach light weight with satisfying the requirement of dynamic stiffness. Finally random vibration analysis is applied to the initial structure. In the mean time random vibration test is carried out to qualify the analysis method. After the qualification a random vibration analysis is applied to the optimized support structure to get the rms of displacement response and acceleration response of the support to validate whether the optimized structure is appropriate. The results indicate that the dynamic stiffness of the optimized support structure satisfies the design requirements and its weight is lighter 49.38% than that of the initial one. This research can be a reference to the structure design of supports under random loads and the result has been applied to the development and manufacture of a prototype aerocraft. 2010 IEEE.

Reflective foveated optical imaging system based on liquid crystal spatial light modulator (EI CONFERENCE) 会议论文 OAI收割
Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China
Peng Q.-Q.; Chang J.; Feng S.-L.; Wang R.-R.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

Based on reflective liquid crystal spatial light modulator (SLM) a new foveated optical imaging system is proposed. High quality imaging can be realized at any region of interest (ROI) within the field-of-view (FOV) by utilizing the SLM to correct the aberration of different regions dynamically. A reflective cassegrain optical structure is proposed which is designed optimized and matched with the reflective SLM to construct a more practical foveated imaging system. This reflective imaging system has a large aperture so that enough light can reach the image plane. It also makes the total length of the system shorter and therefore more practical. We also simulate and analyze the system. This kind of foveated optical imaging system can be applied in wide FOV imaging aspects to reduce bandwidth and optics complexity and to achieve weight reduction and miniaturization. 2010 Copyright SPIE - The International Society for Optical Engineering.

Research on the support structure of the primary mirror of large-aperture telescope (EI CONFERENCE) 会议论文 OAI收割
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Yang W.; Jingxu Z.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

Large-aperture telescope can be used in surveying battlefield researching landform searching object real-time monitoring imaging detecting and identifying spatial targets and so on. A large-aperture telescope for achieving high resolution power is designed to monitor spatial target and image in real time. Real-time monitoring plays an important role in military conflicts. The orbit parameter of object quantity geometrical shape parameter and so on can be obtained by detect spatial target. With the development of optical technology people require larger aperture in optics-electronic (OE) system. By increasing optical aperture the ability of collecting light and resolution power in the system can be enhanced. But the support structure of the primary mirror of large-aperture telescope will be a very difficult problem. With the increase of primary mirror aperture the weight of the primary mirror will become larger than before. The root mean square (rms) of the primary mirror is affected by many factors such as deadweight deformation of heat environment and so on. Due to the primary mirror of telescope is an important component of telescope system. By reducing the weight of primary mirror precision of the system is ensured. During the designing phase one can consider the supporting project of the primary mirror synthetically and analyze it roundly according to technical requirement of optical system and the effect factors. The final structural design can be reasonable. In an astronomical telescope the surface of reflector is an important part for collecting dark radiation of celestial bodies. Its surface shape will have an effect on collecting efficiency of telescope radiant energy directly. So the rms must be very high. Optical system of large aperture small wavelength and small focus can receive maximal light intensity. For ground-based optical astronomical telescope the design proposed in the paper can satisfy the requirement of the possible minimum atmosphere seeing at astronomical observatory site and exert the use efficiency of the telescope adequately. So the accuracy of the traditional surface of reflector can assure that 90% of all the light energy can be focused on within the angle diameter range of the minimum atmosphere seeing then 100% of light energy should be focused on the angle diameter range of minimum atmosphere seeing. Because the rms of mirror is very high precise surface machining and accurate the support of mirror are very important tasks during designing and manufacturing the telescope. In the paper various support techniques of a large-aperture telescope primary mirror are discussed and a 3.5 meter telescope system at the Starfire Optical Range (SOR) overviewed simply which was operated by the Directed Energy Directorate of the Air Force Research Laboratory Kirtland AFB NM USA from the ground-based O-E system for the observations of spatial target. We also analyze Theoretical elastic deformation of the Steward Observatory 2.3 meter mirror is analyzed.