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Effect of Ta addition on the microstructures and mechanical properties of in situ bi-phase (TiB2-TiCxNy)/(Ni-Ta) cermets 期刊论文
Ceramics International, 2019, 卷号: 45, 期号: 4, 页码: 4408-4417
作者:  H.Y.Yang;  Z.Wang;  S.L.Shu;  J.B.Lu
收藏  |  浏览/下载：0/0  |  提交时间：2020/08/24
Microstructures and Compressive Properties of Al Matrix Composites Reinforced with Bimodal Hybrid In-Situ Nano-/Micro-Sized TiC Particles 期刊论文
Materials, 2018, 卷号: 11, 期号: 8, 页码: 13
作者:  Qiu, F.;  Tong, H. T.;  Gao, Y. Y.;  Zou, Q.;  Dong, B. X.
收藏  |  浏览/下载：0/0  |  提交时间：2019/09/17
Study on the difference between turfy soil and normal peat soil in China (EI CONFERENCE) 会议论文
2011 International Conference on Vibration, Structural Engineering and Measurement, ICVSEM2011, October 21, 2011 - October 23, 2011, Shanghai, China
Yan L.; Nie L.; Xu K.; Su Z. D.
收藏  |  浏览/下载：29/0  |  提交时间：2013/03/25
As the special soil  turfy soil and peat soil in China contained some similar properties with high void ratio  high water content  high organic content  etc. But turfy soil also had properties which difference from peat soil. In this paper  based on the formation of the cause and geological environment and geomorphologic characteristics of geological in the quaternary  took the typical and widespread turfy soil and peat soil regions for example  systematically discussed the material composition and macroscopic and microcosmic structural features  put further research on the physical chemistry mechanical characteristics. Then the come to the conclusion that the essential reason for difference between turfy soil and peat soil were decomposition degree and organic content. The result that worse engineering properties such as higher the moisture content  porosity  compressibility  internal cohesion and the lower specific weight  consolidation coefficient and permeability were due to the lower decomposition degree and higher organic content of turfy soil than peat soil. It can provide reference to the practical projects of turfy soil to distinguish peat soil according to this characteristic. (2012) Trans Tech Publications.  
Study of the neural network constitutive models for turfy soil with different decomposition degree (EI CONFERENCE) 会议论文
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
Lv Y.; Nie L.; Xu K.
收藏  |  浏览/下载：16/0  |  提交时间：2013/03/25
The turfy soil is of a special humus soil. The decomposition degree is the main factor on the physical and mechanical properties of turfy soil. To build the turfy soil constitutive model  there are a few shortages such as the calculation cumbersome and low accuracy for parameter value with the method of traditional models. Furthermore  those methods did not reflect the influence of strength that effected by decomposition degree of the turfy soil. In this paper  the relationship of stress-strain with different decomposition degrees of turfy soil was carried out through indoor tests. Based on above experimental results  an improved method  which divided into different zones according to different decomposition degrees of turfy soil and calculated combining with neural network constitutive model is put forward. The result shows that  the neural network of turfy soil has good fitting precision and good generalization ability. It can fully describe the influence of the turfy soil. 2011 IEEE.  
Research on servo controller for high speed tracking system (EI CONFERENCE) 会议论文
2011 International Conference on Mechatronic Systems and Automation Systems, MSAS 2011, July 23, 2011 - July 24, 2011, Xi'an, China
Li M.; Gao H.
收藏  |  浏览/下载：14/0  |  提交时间：2013/03/25
To meet requirement of swiftness and minimization for the tracking system as well as realize horizontal high accuracy tracking measurement  the automatic servo tracking measurement system has been designed. The two closed loop control  bisection method and compound control have been applied into the system. Experimental results show that the maximum tracking error can be limited to less than 0.5and the regulator time can be 0.04s. The control project resonance frequency should be more than 200Hz and the sample frequency should be more than 400Hz to meet the control accuracy requirement. And these specific mechanical properties indexes are useful to mechanical working to make sure the design can be realization. So the research in this paper has important value to the engineering practice. (2011) Trans Tech Publications.  
Dome design and coupled thermal-mechanical analysis of supersonic missile (EI CONFERENCE) 会议论文
2009 International Conference on Optical Instruments and Technology, OIT 2009, October 19, 2009 - October 22, 2009, Shanghai, China
Xing-qiao A.; Qun W.; Hong-guang J.
收藏  |  浏览/下载：39/0  |  提交时间：2013/03/25
A review of high-speed flow pressure and aerodynamic heating effect on Supersonic missile's dome is given. The dome should have excellent properties in optical  mechanical and chemical characteristics. A design of dome on supersonic mode is described according to tactical guide line of a missile. The dome made of quartz which is about 8mm thick and 141mm in window diameter. To check up the reliability of the dome  a reasonable finite element model (FEM) of dome is established  and a thermal-mechanical Analysis to the dome by finite element software NASTRAN has carried on  through these can obtained the distribution of temperature field and stress field when the speed is 2.3Ma. The results indicated that the stress was concentrated in the joint of the dome end and the Missile Section  and the maximum stress was 16.4Mpa. The stress of other nodes was smaller than the allowable stress of quartz glass. Reference to the results of the analysis  a lightweight revision to the dome structural dimension and a new method of dome fixing have put forward  which can reduce the stress concentration. 2009 SPIE.  
Fabrication technique of large-scale lightweight SiC space mirror (EI CONFERENCE) 会议论文
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Zhang G.; Zhao R.; Zhao W.
收藏  |  浏览/下载：13/0  |  提交时间：2013/03/25
Silicon carbide (SiC) is a new type candidate material for large-scale lightweight space mirror. Its low thermal distortion  high stiffness  high optical quality  and its dimensional stability are better than other traditional optical substrate materials such as ULE  Zerodure  Beryllium (Be) and so on. In this paper  the lightweight silicon carbide space mirror blank was fabricated by reaction sintering. As a space born mirror material  silicon carbide must be an optical grade ceramic. So we prepared the silicon carbide green body with gel-casting method. Then some carbon materials were supplemented into the green body which will bring reaction-sintering with silicon in a vacuum furnace during 1500-1600C  ultimately the reaction bonded silicon carbide was made. The diameter of SiC space mirror blank we have made is 680mm. If expanding the size of the vacuum furnace  bigger mirror blank can be obtained. The test results show that the mechanical and thermal properties of RB-SiC are excellent with bending strength of 350MPa  fracture toughness of 4.1 MPa·m1/2 and coefficient of thermal expansion(CET) of 2.6710-6/K. The surface roughness(RMS) could be better than 3nm.  
Design of dual-FOV refractive/diffractive LWIR optical system (EI CONFERENCE) 会议论文
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Advanced Optical Manufacturing Technologies, July 8, 2007 - July 12, 2007, Chengdu, China
Zhang J.-P.; Wang L.-J.; Zhang X.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
An infrared-optical zoom system using binary element is proposed in this paper. The two main advantages of the zoom system introducing here are: bigger F-number and lower cost. The primary optical properties are: F/#=1  Second  Others  zoom ratio =1:4  binary element is used to correct the chromatical aberration by taking the advantage of negative dispersion characteristics and the cost of the system is lower than that of conventional ones with Zinc Selenide (Znse) material at the same level. In the binary element is rotational symmetric with one step which is easy to fabricate  in order to balance 5th spherical aberration  and dual field are 26.6 and 5.6respectively. Wider field of view is used for search and the smaller one is used for imaging details. This system uses un-cooled infrared detector with 320240 pixels and 45m pixel size. The F-number matches the sensitivity range of the detector array. Three aspects are considered during design process to make the system more satisfactory and more achievable. First  5th coma aberration and 5th astigmatic aberration  the manner of zoom is accomplished by exchanging tow lenses into the smaller field of view system layout. The lens exchange manner faces the requirement of simple system structure and good image quality in both focal points. It can also make the system more feasible in the alignment process than mechanical-zooming manner and optical-zooming manner  high-order asphere surfaces with 2th order to 10 th order are also hired in the system. Asphere surface is useful in compressing the system and improving optical system transmittance. This kind asphere surface is on industrial level featuring low cost and easy to fabricate. It is shown that good image quality can achieved by implementing five Germanium lenses and the transmittance of system is 72%. All aberrations are diffraction-limited  both spherical aberration and astigmatic aberration are corrected. When the field of view(FOV) is 26.6 and the focal length is 152mm  MTF at Nyquist frequency(11lp/mm) is great than 0.7. The spherical aberration is -0.0073. The coma aberration is 0.0978 and the astigmatic aberration is -0.013. When the field of view(FOV) is 5.6 and the focal length is 38mm  MTF at Nyquist frequency is great than 0.8 with spherical aberration -0.0046  the coma aberration 0.055 and astigmatic aberration 0.034.  
Fabrication and electron emission of carbon microtubes (EI CONFERENCE) 会议论文
Technical Digest of the 18th International Vacuum Nanoelectronics Conference, IVNC 2005, July 10, 2005 - July 14, 2005, Oxford, United kingdom
Wang W.; Xia Y.; Lei D.; Chen S.; Liu L.; Chen M.; Liang J.
收藏  |  浏览/下载：29/0  |  提交时间：2013/03/25
Carbon nanotubes have been attracting attention because of their unique physical properties and their application potential for field emission cathode. Carbon nanotubes possess the following properties favorable for field emission material  such as a high aspect ratio and sharp tip  high chemical stability  high mechanical strength  stable at high temperature. Some research works on carbon nanotubes field emitter and field emission display have been reported. Here  a kind of carbon microtubes and its field emission properties are introduced. They have some different properties with carbon nanotubes  and the density is lower than carbon nanotubes bundles. These carbon microtubes are directly synthesized by liquidoid epitaxy method on silicon substrates at low temperature. The field emission properties of carbon microtubes are reported too. Carbon microtubes film is synthesized in liquid by electrolysis. The graphite plate is as anode  and n-silicon substrate with resistivity of 4-8 cm is as cathode. The electrolysis current is about 5-8mA/cm2  and applied voltage is 800-1500V. Temperatures of the methanol base solution is maintained at 60C in process of deposition of carbon microtubes. Carbon microtubes film is observed by scanning electron microscopy(SEM)  as shown in fig.1(a  b). The wall's thickness of carbon microtube is about 60nm. The diameter of carbon microtube is about 0.8 m. Raman spectrum of carbon microtubes film shows the two peaks at 1342and 1560cm-1. The field emission properties of carbon microtubes are measured in high vacuum chamber(10-5Pa). The emission area of carbon microtubes is 0.5cm 0.5cm. The threshold of field emission of the carbon microtubes film is about 3.6V/ m. Field emission property of carbon microtubes film is shown in fig.2. Another  when the electric field between anode and cathode is 10V/ m  the electric field distribution on single carbon microtube is also given after calculation according to electric field theory. Fig 3 shows that electric field distribution vertical section on the of single carbon microtube top with 2 m of highness. These results may help us to understand field emission properties of carbon microtubes. According to research results  it is found that liquidoid synthesis is simple method to produce carbon microtubes cold cathode material  and the carbon microtubes have better field emission properties. 2005 IEEE.  

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