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<title cf:type="text"><![CDATA[Editorial department of the Journal of National University of Defense Technology -->航天工程·电子科学与技术]]></title>
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<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis and correction of BDS-3 MEO satellites pseudorange multipath error]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104001]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[From 2018 to 2019, the BDS-3(BeiDou navigation satellite system phase Ⅲ) has successively launched more than a dozen MEO(medium earth orbit) satellites, gradually completing global networking. The BDS-3 satellites simultaneously broadcast smooth transition signals B1I, B3I and new signals B1C, B2a.The analysis of actual data shows that the civil B1C frequency and B1I frequency of MEO satellites contains obvious pseudorange multipath errors. Due to the orbital characteristics of MEO satellites, this phenomenon is very significant at low altitude angles of satellites. Two algorithms of MHM(multipath hemispherical map) and CNMC(code noise and multipath correction ) were used to correct the pseudorange multipath error. The correction of the pseudorange multipath error by the MHM algorithm was not obvious. The CNMC algorithm can reduce the B1C frequency multipath error from 0.11 m to 0.03 m and reduce the B1I frequency multipath error from 0.074 m to 0.024 m when the altitude angle is greater than 30 degrees. The multipath error of the MEO satellite is reduced by about 60%.]]></description>
<pubDate>2021/7/20 0:00:00</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[LIU Jiulong, CAO Yueling, HU Xiaogong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LIU Jiulong, CAO Yueling, HU Xiaogong</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104001]]></guid><cfi:id>15</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Optimal design and performance analysis of satellite navigation system power-enhanced sub-constellation]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104002]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The power-enhancement technology of GNSS is one of the effective measures to improve the anti-jamming capability of regional satellite navigation signals. How to select power enhancement sub-constellation which has less satellite quantity and better service performance from global constellation is a problem in urgent need to be solved urgently in the construction of modern navigation system. An optimal design method of power-enhanced sub-constellation based on minimum number of satellites was proposed. The design process, mathematical model and optimal solution search strategy were introduced. Availability level, accuracy level and coverage area were defined to evaluate the performance of the power-enhanced sub-constellation. Taking GPS as an example, the optimal design and performance evaluation of power-enhanced sub-constellation was carried out for the application background of covering point target and regional target. The results of simulation show that power enhancement at any target point worldwide requires 12~17 satellites. 18 satellites are needed to achieve continuous coverage to the coastal area of China. And, covering the entire Asia-Pacific region requires full constellation satellite enhancements to meet continuity and accuracy requirements. In this case, the service range of optimal power enhanced sub-constellation can be extended to the whole world.]]></description>
<pubDate>2021/7/20 17:26:13</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[LYU Zhicheng, LI Zhengrong, MOU Weihua, HUANG Long, OU Gang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LYU Zhicheng, LI Zhengrong, MOU Weihua, HUANG Long, OU Gang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104002]]></guid><cfi:id>14</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[High-altitude balloon shape calculation and general algorithm design]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104003]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[High-altitude balloon provides a reliable low-cost platform for high altitude scientific experiments. The shape of the balloon is directly adopted as natural-shape or based on natural-shape； however, how to simply and quickly solve the natural-shape equation general-purpose is a difficult problem. The mature solution tool in the field of optimal control—gauss pseudospectral optimization software was used to solve the natural-shape balloon equation which is transformed into the optimal control description. Furthermore, a general algorithm was designed to solve the natural-shape balloon shape with any spherical control factor and any height by analyzing the shape data. Results show that this algorithm can calculate the required natural-shape without adjusting parameters, which is convenient for researchers to quickly obtain a large amount of required spherical data.]]></description>
<pubDate>2021/7/20 0:00:00</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[ZHOU Jianghua, JIN Weicheng, LI Zhibin]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHOU Jianghua, JIN Weicheng, LI Zhibin</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104003]]></guid><cfi:id>13</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Texture randomization in structure-dominant object detection]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104004]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Region-based detectors with convolutional neural networks tend to learn textural rather structural feature and thus face substantial difficulties in detecting objects with various textures. To tackle this problem, the texture randomization to augment the synthetic training image dataset was employed and a novel method for structure-aware object detection was proposed. The texture-randomized simulation data were generated by rendering 3D model with varied textures using Blender. Experiments on synthetic and real images indicate that the proposed method is capable of robustly detecting texture-varied objects based on structural information.]]></description>
<pubDate>2021/7/20 17:26:13</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[WANG Zi, BI Daoming, ZHOU Jiexin, SUN Xiaoliang, YU Qifeng]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WANG Zi, BI Daoming, ZHOU Jiexin, SUN Xiaoliang, YU Qifeng</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104004]]></guid><cfi:id>12</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Transient current calculation of rectifier generator under converter short circuit fault]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104005]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Considering the short circuit fault at DC(direct-current) converter side, the rectifier generator with DC converter can be equivalent to the rectifier generator suddenly applied with RLC(resistance inductance capacitance) load, and its transient current calculation is directly related to DC fault diagnosis and protection. When the RLC load was equivalent from the DC side to the AC(alternating-current) side, the transient current was equivalent to the three-phase short circuit current under the condition of the synchronous generator in series of RLC. Through the expression of the transient current, the analytical expression of the transient current was obtained by calculating the initial value, final value and time constant with the method of analogizing the three-phase short-circuit current′s calculating process of the synchronous generator, and the peak value and peak time of the current were given. Finally, the validity of the analytical expression is verified by simulation,which can be used for the improvement of the diagnosis and the determination of the protection way of DC faults.]]></description>
<pubDate>2021/7/20 17:26:14</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[HOU Changwu, ZHANG Xiaofeng, HUANG Jing, WU Benxiang]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HOU Changwu, ZHANG Xiaofeng, HUANG Jing, WU Benxiang</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104005]]></guid><cfi:id>11</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Improved random sampling consensus algorithm using local pixel matching]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104006]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to improve the registration precision and robustness of image splicing, an improved random sampling consensus algorithm based on local pixel matching was proposed. After completing image feature extracting and feature matching with the scale invariant feature transform operator or other operator, using the local pixels that are independent of feature matching points, then the optimal configuration of the four pairs of feature matching points, and the best homography matrix were determined by matching the local pixel of the reference image with the mapped local pixel of the image to be stitched. The experimental results show that, compared with the classical random sampling consensus algorithm, the computation time is close, the homography matrix is more accurate, and the image mosaic is more robust.]]></description>
<pubDate>2021/7/20 17:26:14</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[DAI Weihua, LIU Shengchun, ZHAO Shen, PENG Hua, ZHANG Hao, HUANG Zhigang, LI Xiaolin]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>DAI Weihua, LIU Shengchun, ZHAO Shen, PENG Hua, ZHANG Hao, HUANG Zhigang, LI Xiaolin</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104006]]></guid><cfi:id>10</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Stray inductance extraction method for battery pack in electromagnetic launch]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104007]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In a lithium-ion battery energy storage system for electromagnetic launch, the accurate extraction of the battery pack stray inductance is significant for designing a reasonable system solution. To meet this demand, the process of battery pack pulse discharge was modeled and analyzed, and the discharge stage suitable for stray inductance extraction was obtained. The method of solving the numerical differentiation by discrete Fourier transform was changed to the sliding-window recursive form, which was combined with multi-innovation least square algorithm, so a novel stray inductance extraction method was proposed, which can make full use of waveform data. Experimental results show that this method can extract stray inductance more accurately and reliably than the traditional method, and the calculation results are consistent under different discharge currents.]]></description>
<pubDate>2021/7/20 17:26:14</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[LONG Xinlin, YAN Kangwei, LU Junyong, LIU Yingquan, ZHOU Ren]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>LONG Xinlin, YAN Kangwei, LU Junyong, LIU Yingquan, ZHOU Ren</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202104007]]></guid><cfi:id>9</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Investigation on the aging mechanism of HTPB propellant in SRM long-term storage]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301010]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In order to reveal the aging mechanism of solid propellant grain during the long-term storage, a HTPB (hydroxyl-terminated polybutadiene) propellant rocket motor which was moulded by casting and stored naturally for 19 years was dissected. Samples were taken along the radial position of the propellant grains, and were tested and analyzed by means of SEM(scanning electron microscope), EDX(energy dispersive X-ray spectrometer), infrared absorption spectroscopy and cross-linking density. Results show that the aging degree of propellant is not the same at different positions of grain. The closer the position is to the non-metallic case, the more serious the aging degree of propellant is. Further analysis shows that, in addition to the effects of CC double bond oxidation chain breaking and condensation of —OH on propellant aging, Al<sup>3+</sup> ions produced by the oxidation of Al powder catalyzes the addition reaction of HTPB′s CC double bond with Cl<sub>2</sub> or water to form CCl double bond and secondary alcohol, and the uneven migration and distribution of aluminum ions will cause the uneven aging of grain. The research results are of great significance to the improvement of propellant aging performance and the research of anti-aging measures.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[GUO Yu, SHEN Zhibin, LI Haiyang, ZHANG Xuan, LI Zhijie]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>GUO Yu, SHEN Zhibin, LI Haiyang, ZHANG Xuan, LI Zhijie</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301010]]></guid><cfi:id>8</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Blast resistant and shock absorption design for missile-canister system in silo]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301011]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[To improve the survival ability of cold launch missile in silo, the research on blast resistant and shock absorption design had been performed. Finite element models were established for missile-canister system in different shock absorption ways. The dynamic responses under blast-induced ground shock were calculated. The vibration reducing performances of several shock absorption systems were compared, including vertical suspension mode, lower supporting mode and slant suspension mode. Meanwhile, the influences of stiffness and damping on the shock absorbing performance were investigated. The results show that the vibration reducing performance of vertical suspension mode is slightly better than that of lower supporting mode, and that of slant suspension mode is worst. The vibration reducing performance of vertical suspension shock absorption system can be significantly improved by properly decreasing its stiffness and damping.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[ZHOU Anfeng, GUO Zhen, LI Daokui, ZHOU Shiming, JIANG Renwei]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHOU Anfeng, GUO Zhen, LI Daokui, ZHOU Shiming, JIANG Renwei</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301011]]></guid><cfi:id>7</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Real-gas effects research associated with cryogenic transonic wind tunnel]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301012]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The thermodynamic and calorific of the gas in wind tunnel will be imperfect when the wind tunnel operates under cryogenic temperature. In this case, the real gas effects should be considered for calculating flow parameters. The change laws of the compressibility factor and specific heart ratio for nitrogen gas under the ranges of pressures(100～450 kPa)and temperatures(100～323 K) were presented. By introducing the isentropic expansion coefficient into one-dimensional perfect gas flow equations, the computational analysis model for cryogenic wind tunnel flow parameters was developed, and the operating envelope of transonic wind tunnel considering the gas liquefaction temperature and pressure under high speed was obtained. The analysis results show that for the ranges of pressures (115～450 kPa) and temperatures (110～323 K) that cover the range of operation of transonic cryogenic wind tunnel, the maximum deviation of the various isentropic parameters from the ideal values is about 1% or less, and this deviation would be insignificant for the aerodynamic designing of the cryogenic transonic wind tunnel.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[HUANG Zhilong, WANG Ning, SHI Zhiwei, LIAO Daxiong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HUANG Zhilong, WANG Ning, SHI Zhiwei, LIAO Daxiong</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301012]]></guid><cfi:id>6</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Co-simulation of reliability optimization design for turbine disk′s fatigue life with its core optimization strategy]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301013]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[Turbine disk is one of the main components of aero-engine. Once a critical failure occurs, it will lead to serious consequences. On the basis of fully considering the uncertain factors affecting high-low cycle complex fatigue life of turbine disks, co-simulation platform of reliability optimization with high-low cycle compound fatigue life for turbine disk was designed by MATLAB. The uncertain factors affecting high-low cycle complex fatigue life of turbine disks are full considered in the platform. Based on the common requirements of lifetime function and lifetime reliability analysis limit state function, a strategy of sharing training sample points in adaptive construction of lifetime function Kriging model and lifetime reliability limit state surface Kriging model in the process of optimization iteration was proposed. Meanwhile, a learning function for constructing Kriging model of lifetime function was proposed. The high-low cycle complex fatigue life reliability optimization of turbine disk center and mortise were completed using the co-simulation platform. The results show that the local maximum stress of the optimal result is significantly reduced, the average life-cycle is increased, and the reliability constraints are satisfied.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[ZHANG Wenxin, LYU Zhenzhou]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>ZHANG Wenxin, LYU Zhenzhou</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301013]]></guid><cfi:id>5</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Influence of rain attenuation on the I/N distribution of Q-band geostationary satellite orbit downlink]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301014]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[In view of the propagation characteristics of Q-band communication links that were severely affected by conditions such as rainfall, fog and atmospheric absorption, based on the analysis of the propagation loss of the Q-band geostationary satellite orbit downlink, the influence of rainfall attenuation on the I/N distribution under the interference scenario of the earth station co-location was studied. A method to calculate the propagation loss of Q-band downlink combined with rainfall distribution was proposed, and a functional model for I/N combined p% that the percentage of time when rainfall attenuation exceeds a threshold value was established. The influence of p% on the distribution of I/N was analyzed, and the average annual interference distribution was forecast. This method was used to analyze the influence of the CHINASAT-G-115.5E satellite network which was registered by the ITU, and the results show that the lower the p%, the more obvious the influence of rain attenuation on the communication link. When p＜0.5, the attenuation threshold changes faster. When the location of earth station and the orbit longitude of the interfering satellite are fixed, the smaller the p%, the smaller the minimum value of I/N in the annual average 1-p% time. This method can be applied to study the interference distribution of other orbital satellites, and provide a reference for interference avoidance.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[WANG Jing, YAO Xiujuan, GAO Xiang, ZHI Jia, CHEN Tuo, DONG Suhui, SUN Yunlong]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>WANG Jing, YAO Xiujuan, GAO Xiang, ZHI Jia, CHEN Tuo, DONG Suhui, SUN Yunlong</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301014]]></guid><cfi:id>4</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Influence of electrochemistry polarization state on electric field model of submarine propeller disturbance]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301015]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The electric field distribution of submarine is affected by the degradation of coating properties during service. With material polarization as boundary condition, three electrostatic field models were established by using boundary element method,including submarine coating performance deterioration, coating penetration corrosion and coating local damage polarization. The propeller disturbance electric field model was analyzed from time domain and frequency domain characteristics. The results show that electrochemical polarization state has a significant effect on the potential and harmonic of propeller disturbance electric field. Under the three boundary conditions of constant potential, linear polarization and nonlinear polarization, when the propeller rotates at the same frequency to disturb the electrostatic field, the proportion of frequency components of each model is significantly different. Under the nonlinear boundary condition, the difference between the disturbance frequency and the ratio of twice disturbance frequency is the largest. Under the linear boundary condition, the difference between the disturbance frequency and the ratio of twice disturbance frequency is the smallest. Under three kinds of boundary conditions, the harmonic range of the electric field model above three times of the disturbance frequency will change. The harmonic range of the electric field model is the smallest under the constant potential boundary condition, and the harmonic range is the largest under the nonlinear boundary condition.]]></description>
<pubDate>2023/1/16 9:46:30</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[HE Fang, WANG Xiangjun]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>HE Fang, WANG Xiangjun</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301015]]></guid><cfi:id>3</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Analysis of the thermal effect of electromagnetic pulse on high frequency structure]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301016]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[For Cerenkov-type devices, the thermal desorption caused by the temperature rise of the high-frequency structure can cause radio frequency breakdown, which in turn leads to a decrease in output power and a shortened pulse. Based on this, the heating temperature rise effect of electromagnetic pulses on the high-frequency structure was studied, the temperature rise formula of the high-frequency structure was deduced, the scope of application of the theoretical formula was pointed out, and a numerical method to solve the temperature rise of the specimen was given. Taking the two-period 1 MV·cm-1 high-frequency structure as an example, the numerical calculation and simulation study of temperature rise were carried out. Results show that the temperature rise effect of a single pulse with a pulse width of 100 ns on the stainless steel specimen is significantly higher than that of other materials. When the system is working at a high repetition frequency, the temperature rise of electromagnetic pulses may cause the metal material to reach the threshold of gas desorption and cause the gas to desorb to form a local high pressure. The research in the thesis can provide reference for the research of gas desorption and radio frequency breakdown in high power microwave sources.]]></description>
<pubDate>2023/1/16 0:00:00</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[YUAN Yuzhang, MENG Jin, ZHU Danni, WANG Haitao, CUI Yancheng]]></author>
<atom:author xmlns:atom="http://www.w3.org/2005/Atom">
<atom:name>YUAN Yuzhang, MENG Jin, ZHU Danni, WANG Haitao, CUI Yancheng</atom:name>
</atom:author>
<guid><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301016]]></guid><cfi:id>2</cfi:id><cfi:read>true</cfi:read></item>
<item>
<title xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="text"><![CDATA[Binocular vision measurement of sabot discard of shell piercing projectile]]></title>
<link><![CDATA[http://journal.nudt.edu.cn/gfkjdxxben/article/abstract/202301017]]></link>
<description xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" cf:type="html"><![CDATA[The sabot discard process of shell piercing projectile has significance on the flight stability and strike efficiency of it. Aiming at the six degrees of freedom movement process of shell piercing projectile after leaving the chamber, a measurement method of sabot discard angle based on the principle of binocular vision was proposed. By setting some markers on the surface of projectile and sabot, the recognition and tracking of the markers were realized with the image processing and tracking algorithms. The spatial locations of these marker were calculated by combining with the binocular calibrated space parameters, and the discard angle of sabot relative to the projectile was obtained. Meanwhile, the accuracy of the method above was validated by experiment which was proved to be 2%. Taking the shell piercing projectile launching at initial velocities of 1 550 m/s and 1 750 m/s conducted in the laboratory as an example, the discard trajectories under different muzzle velocity were measured and analyzed. The results show that the faster the discard initial velocity is, the closer the discard trajectory is to the projectile.]]></description>
<pubDate>2023/1/16 9:46:31</pubDate>
<category><![CDATA[航天工程·电子科学与技术]]></category>
<author><![CDATA[LI Xiangping, LU Junyong, ZHANG Xiao, CHENG Long, LI Songcheng]]></author>
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<atom:name>LI Xiangping, LU Junyong, ZHANG Xiao, CHENG Long, LI Songcheng</atom:name>
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