Subjects: Physics >> Nuclear Physics Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-02-27
LUFenhua
TANG Shuwen
FU Shengwei
YAN Duo
MA Peng
YANG Haibo
YU Yuhong
ZHANG Xueheng
WANG Shitao
ZHANG Yongjie
FANG Fang
LIU Tuoqi
XU Yingfeng
LI Zhiyao
LIU Xiangman
WEI Xiaobao
SUN Zhiyu
Abstract： The high-intensity heavy-ion accelerator facility (HIAF) under construction is equipped with an advanced radioactive beam line HFRS, which will provide a new opportunity for the research of high-energy radionuclide beam physics in China.The characteristic of HFRS is high intensity, This puts forward very strict requirements for particle recognition energy loss detector.The traditional energy loss detector generally adopts the analog plug-in technology route of preamplifier, main amplifier and ADC for signal processing.This scheme has some problems, such as slow electronic response, poor flexibility and difficulty in dealing with serious pulse pile-up at high count rate. We propose a new applicable to high count rate energy loss detector scheme.The signal of the energy loss detector is initially amplified by the fast charge sensitive preamplifier, and Then the waveform is directly collected by waveform digitizer and then processed by digital algorithm.And use the Multiple Sampling Ionization Chamber (MUSIC) of secondary beam line of lanzhou RIBLL2 for the radioactive source and beam test.Using the 3 components 𝛼 source test, using digital shaping algorithm processing for acquisition of waveform, energy resolution (FWHM) of up to 1.31%.In RIBLL2 provide 300 MeV/u of 56Fe beam test, uses the time constant of 𝜏f = 2 𝜇𝑠 of fast charge sensitive preamplifier on the count rate is close to 1 MHz is still not occurred pulse pile-up obviously.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-06-21 Cooperative journals: 《应用力学学报》
Abstract：
The deterioration of lift-drag ratio of aerofoil surface caused by icing is a direct threat to flight safety and has always been a hot issue in the aviation field.In order to reproduce the icing process of the aerofoil surface and analyze the mechanism of aerofoil surface icing/anti-icing,it is necessary to carry out aerofoil surface icing test.In order to quantitatively characterize the thickness and shape of ice in aircraft icing tests,domestic and foreign researchers have carried out a large number of effective test methods.This paper systematically summarizes the measurement methods of aerofoil area ice thickness and ice shape and icing sensing devices proposed in recent years,and divides them into visual method,resonance method,optical method,electrical method,thermal method,waveguide method,hybrid method,and other measurement methods according to the physical principle.The working principle,advantages and disadvantages,and application scope of each method are briefly introduced.It is expected to provide useful reference for the technical development of aerofoil surface icing test and anti-icing system design.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： This paper studies the forward flight dynamic model of tilt rotor unbalanced load proposed byJohnson , and applies its blade analysis method to the modal analysis of helicopter rotor system.Under theassumption of rigidity , the flapping and shimmy motion equations of helicopter rotor blade under the com-bined action of elastic damping and inertial force are derived , and the corresponding motion equations infixed and rotating coordinate systems are given.By introducing the assumption of uniform inflow and lineartorsion , the theoretical analytical solution of the equation of motion is obtained.Then , using the superposi-tion principle , the axial motion equation of the hub is obtained; Newmark method is used to solve the vibration differential equation , and finally the axis motion trajectory of helicopter rotor is obtained.Taking a hel-icopter rotor system as an example , the accuracy of the rotor blade modal analysis method proposed in thispaper is verified , and the optimal solution step selection method considering both calculation accuracy andefficiency is given. 'The hub axis trajectory under typical flight state is predicted , which provides a basicmethod and technical reference for the design of helicopter rotor system.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： In the process of aircraft service , it will experience complex dynamic processes such as groundtaxiing and maneuver etc.'The aireraft structure and airborne equipment will bear the individual or jointeffect of various dynamic loads during these processes. The induced structural dynamic problems are di-rectly related to the aircraft service safety and passengers’ride comfort. This paper sorts out the require-ments of structural dynamics in the military airplane structural integrity program and strength specification,as well as the airworthiness regulation of civil aircraft. The relationship between the structural dynamicsand R&D of aviation equipment is presented.'The main issues of aircraft structural dynamics are classifiedfrom the aspects of loads , structure , response and control.At last , the prospect of aircraft structural dynam-ics is briefly concluded considering the needs in aircraft equipment research and the newly developed vi-bration techniques.
Subjects: Materials Science >> Materials Science (General) Subjects: Energy Science >> Energy Science （General） submitted time 2016-11-15 Cooperative journals: 《金属学报》
Abstract：基于同时满足连铸水模拟实验中Re和Fr相似要求，建立了一套可全尺度模拟连铸过程流动的实验平台。利用该平台的NI图像处理与PIV粒子测速技术，对特厚板连铸用中间包内速度场、涡量场、RTD等流动特征进行研究。结果表明，中间包内流动呈现湍流漩涡状，在注流区形成一个类似“漏斗”状的涡结构，由于中间包内通道的存在，在浇注区形成两个大的环流，并对侧墙有明显冲击，非接触测量获取的RTD与数值模拟结果吻合，长的停留时间和大的死区体积表明该中间包补热的必要性。
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