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为搭建我校博士后学术交流平台，促进学术水平提升，学校博士后管理办公室组织开展博士后学术沙龙活动。本次沙龙由我校博士后李小龙、Muhammad Ammar Khan、王振宇、李轩、张铁笛、魏猛和雷世文分享其研究成果，诚挚邀请感兴趣的师生参加。
一、时 间：2018年3月28日（周三）14：30
二、地 点：清水河校区经管楼宾诺咖啡
三、主办单位：电子科技大学博士后管理办公室
四、承办单位：电子科学与工程学院
电子科技大学博士后联谊会
五、活动安排：
报告一：
（1）主 题：Long Time Coherent Integration Detection Technique for Radar High-Speed Maneuvering Target
（2）主讲人：李小龙 信息与通信工程学院博士后
（3）交流内容：
With the development of science technology, especially the highly maneuvering target and stealth technique, there is a growing need for robust and effective detection of maneuvering target with high speed, which is very meaningful for modern radars to improve their detection performance. Long-time coherent integration (LTCI) technique is one of the most important methods for the improvement of radar detection ability of a weak maneuvering target, whereas the integration performance may be greatly influenced by the range migration (RM) and Doppler frequency migration (DFM) effects induced by target’s high speed and complex motions. In this talk, we briefly discuss the LTCI detection problem for radar high-speed maneuvering target. First, we will introduce the background of the LTCI detection for radar maneuveing target. Then, some new researches about LTCI method of our group will be presented, including LTCI algorithm with parameter searching process, LTCI algorithm without parameter searching, and LTCI algorithm for multi-target scene. Detailed comparisons of different kinds of LTCI methods are also given, including detection ability and computational complexity. Finally, some discussions and future work are presented.
（4）主讲人简介：
Xiaolong Li received the B.S. and the Ph.D. degrees in 2011 and 2017, respectively, both in University of Electronic Science and Technology of China (UESTC), Chengdu. He currently works as a Postdoctoral Fellow in the School of information and communication engineering. His research interests include radar signal detection and parameter estimation, with an emphasis on coherent integration technique for radar maneuvering target detection.
报告二：
（1）主 题：Transport Mechanism and mobility in Electrons only and Holes only Devices.
（2）主讲人：Muhammad Ammar Khan 电子科学与工程学院博士后
（3）交流内容：
The main objective of this work is to study the charge transport phenomenon and mobility behavior in different polymers diodes at different temperature by applying the mobility models
At first our topic will be focus on basic of molecular structure, transport mechanism, and charge carrier mobility. Then we discuss on transport model with double density of state one DOS for free carriers and one for trapped carriers and analyze their results. Next we discuss mobility edge model with new density of state introducing with exponential tail and applied to typical organic diodes and see the J-V results variation. The free holes are treated as non-degenerate, and the trapped holes are treated as degenerate. Further, we introduce the neutral condition (plays an important role in charge transport) with transport model with new density of state and apply to organic diodes and see the results that new DOS is far better than Gaussian DOS. Finally we discuss the modified J-V formula and apply to many MIMs diodes and check its validity. The results calculated from the improved analytic formula are in good agreement with the complete numerical solutions.
主讲人简介：
Muhammad Ammar Khan received Master degree from Gomal University, Pakistan, and Doctor Degree from School of Physical Electronics, UESTC China in 2015.
He currently working as a Postdoctoral Fellow in the School of Electronic Science and Engineering, UESTC. Dr. Ammar Khan is working in the field of Micro Electro Mechanical System resonators and phononic crystals. His main research interests include Organic Semiconductors Polymers, Atomic structures Diodes, Density of States, Transport properties Electrical properties of Materials, Computational Techniques, and Polymers based MEMS & NEMS.
报告三：
（1）主 题：Study of spin wave propagation in heterogeneous magnetic films
（2）主讲人：王振宇 电子科学与工程学院博士后
（3）交流内容：
As collective excitations of the magnetic order in magnetic materials, spin waves can be used to carry, transport, and process information without the physical motion of electrons. As a new information carrier, spin wave needs to have the capabilities of transmitting information from one medium to another. Thus, it is important to study their reflection and refraction at the interface between two magnetic media. Recent studies found that Dzyaloshinskii-Moriya interaction (DMI), an asymmetric exchange interaction, is widely existed in chiral magnets and symmetry-breaking magnetic films. DMI has a significant influence on spin wave propagation, such as the nonreciprocity of spin wave. In this talk, we briefly discuss the spin wave propagation through the interface between two magnetic films with different DMIs. Firstly, we derive the effect of DMI on the spin-wave dispersion relations based on Landau-Lifshitz-Gilbert (LLG) equation and give the generalized Snell’s law, which is used to describe the refraction of spin wave at the DMI interface. Then, micromagnetic simulations are performed to verify our theoretical predictions. We found that some intriguing phenomena, such as negative refraction and total refraction, would occur at the DMI interface when the incident angle of spin wave satisfies some certain conditions. Our finding can offer a new method to measure the strength of DMI and would be helpful for designing the magnonic devices.
（4）主讲人简介：
Zhenyu Wang received the Bachelor degree from Anhui university and Ph.D. degree from Xiamen university. He currently works as a Postdoctoral Fellow in the School of Electronic Science and Engineering. His main research interest include magnetization dynamics, spintronics and magnonics.
报告四：
（1）主 题：Wideband Gap Semiconductor Silicon Carbide Based Power Electronics
（2）主讲人：李轩 电子科学与工程学院博士后
（3）交流内容：
In this talk, the pros and cons of commercially available SiC power devices will be discussed along with a comparison to their Si counterparts. Furthermore, the advantage of SiC power device will be delivered and the reason how the SiC power device can improve the power system will be explained. Part of what I did research is in this talk to promote the development of this area and help related researchers like power supply designers learn more about this new technology and select the right SiC devices suitable for their applications.
（4）主讲人简介：
He received the Bachelor degree of microelectronics from UESTC and Ph.D. degree of Microelectronics and solid Electronics from the same university, in 2011 and 2017, respectively. He has been to North Carolina State University NSF Future Renewable Electric Energy Delivery and Management (FREEDM) center as a research assistant under word renowned experts of power device& power electronics: Alex Huang from 2013~2015.
He currently works as a postdoctoral fellow in the School of Electronic Science and Engineering of UESTC. Dr. Li is working in the field of SiC power device and its suitable package. His research includes wideband gap power semiconductor devices and their emerging energy efficiency package and applications.
报告五：
（1）主 题：Research on Key Technology of Terminal RF Chips and Negative Group Delay Circuits
（2）主讲人：张铁笛 电子科学与工程学院博士后
（3）交流内容：
With the development of communication technology, the requirement of terminal RF circuit integration degree in communication equipment is becoming stricter. The traditional hybrid integration circuit is difficult to meet the needs of miniaturization in modern systems. Under this background, the monolithic integrated circuit has already become a hot spot in recent years because of its high circuit density, stable performance, large-scale production applicability and other advantages. Achieving comprehensive independent intellectual property rights of the terminal RF chip is very important, which not only helps to accelerate the development of Chinese communication field but also enhances the innovation capability and international competitiveness of integrated circuit. In addition, in the field of communication, it has already been known that for the RF signal with bandwidth, the dispersion effect will be produced due to the positive group delay. The negative group delay (NGD) circuits can eliminate this effect and help to optimize the signal integrity, reduce the bit error rate and improve the communication quality. In the academic field, an NGD circuit can be considered to have a characteristic that the group velocity transcends the speed of light, which greatly deepens the understanding of the group velocity. Accordingly, the research of NGD circuit is very important in both theoretical and practical fields. This paper studies the new design methods of terminal RF chip and NGD circuit deeply and systematically. According to the specific needs of circuits, the specific manufacturing processes are used to verify the relevant technology.
（4）主讲人简介：
Tiedi Zhang received the Bachelor degree and Ph.D. degree from University of Electronic Science and Technology of China, in 2010 and 2017, respectively. He currently works as a Postdoctoral Fellow in the School of School of Electronic Science and Engineering. His research interests include RF chips and negative group delay circuits.
报告六：
（1）主 题：Key Techniques of Energy Storage Dielectrics for “Triple Highs” Pulse Capacitor
（2）主讲人：魏猛 电子科学与工程学院博士后
（3）交流内容：
The "Triple Highs" pulse capacitor is a disruptive energy storage capacitor, which combines high power the HIGH output power of traditional electrostatic capacitance with the HIGH energy storage density of electrochemical super-capacitors, and with HIGH temperature/voltage/frequency stability. In this talk, we briefly discuss the problem of triple highs dielectric materials. There are three issues: (1) the sintering theory of full density, (2) the grain with nano-size, (3) balance the defects.
First, we introduce a new sintering kinetic force: phase transition, which provides less energy than solid-state reaction, but more than surface energy. Moreover, optimize the sintering condition for green ceramic with higher density. Then, we discuss the second densification with two-step sintering, which could suppress the grain grow effectively. Finally, we explore how to balance the defect of the ceramic. Actually, the purity of raw materials is not 100%, which containing donor impurity generally. We introduce acceptor to compensate the defect for keeping balance.
（4）主讲人简介：
M. Wei received the Bachelor degree from Jilin University and Ph.D. degree from the University of Electronics Science and Technology of China (UESTC), in 2010 and 2017, respectively. He currently works as a Postdoctoral Fellow in the School of Electronic Science and Engineering of UESTC. Dr. Wei is working in the field of electric information materials and device. His main research interests include sintering theory; high voltage properties; photostructurable glass; electric ceramics; integrate technology and thin film.
报告七：
（1）主 题：Power Gain Optimization Method for Wide-Beam Array Antenna
（2）主讲人：雷世文 电子科学与工程学院博士后
（3）交流内容：
This talk focuses on the problem of maximizing the minimum power gain in a wide mainlobe for array antenna. To obtain the desired power gain pattern, current literatures solve the problem known as shaped-beam pattern synthesis (SBPS) by setting the beam pattern expression as the cost function. The power gain in a certain direction of an antenna is comprehensively decided by the array radiated power density and the total radiated power. Both these two parameters are affected by the selection of the weights of array elements. However, the SBPS-methods don’t take the total radiated power into account. Therefore the SBPS-methods cannot obtain the power gain pattern directly and the optimal power gain pattern, consequently, cannot be ensured. To overcome this deficiency, the power gain expression has been directly used as the cost function in this talk to maximize the minimum power gain in the desired wide-beam mainlobe. Aiming at optimizing the cost function, the paper firstly sets up a power gain optimization problem which has concave form. Termed this optimization problem as the Power Gain Pattern Synthesis (PGPS) problem. The PGPS problem is then converted to be a series of convex sub-problems and an iterative algorithm is proposed to solve it efficiently. Solution to the PGPS problem is proved to be able to achieve higher minimum power gain in a desired wide mainlobe than the results from the SBPS-methods. Comparisons with the existed SBPS-methods validate the effectiveness and advantages of the PGPS-method. Furthermore, the improvement on further suppressing of the sidelobe level for the PGPS problem is discussed.
（4）主讲人简介：
Shiwen Lei received the Bachelor degree from UESTC in 2007, the Master degree from Nanjing Research Institute of Electronic Technology (NRIET) in 2010, and the Ph.D degree from UESTC in 2015. He currently works as a Postdoctoral in the School of Electronic Science and Engineering of UESTC. His major research interests include array antenna design, array antenna synthesis, adaptive signal processing, sparse signal recovery, etc.
电子科技大学博士后管理办公室
2018年3月26日
编辑：林坤 / 审核：罗莎 / 发布：陈伟
