A 60GHz Wireless Cooperative Communication System Based on Switching Beamforming

( Wei Shi ),( Jingjing Wang ),( Yun Liu ),( Qiuna Niu ),( Hao Zhang ),( Chunlei Wu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.4

The challenge of penetrating obstacles along with impact from weak multipath effects makes 60GHz signal very difficult to be transmitted in non-line of sight (NLOS) channel. So 60GHz system is vulnerable to obstructions and thus likely results in link interruption. While the application of cooperative technology to solve link blockage problemin 60GHz system should consider the characteristic of directional transmission for 60GHz signal. Therefore in this paper a system is proposed to solve the link blockage problem in 60GHz NLOS communication environment based on the concept of cooperation and also the beamforming technology, which is the basis of directional transmission for 60GHz communication system. The process of anti-blockage solution with cooperative communication is presented in detail, and the fast switching and recovery schemes are well designed. The theoretical values of symbol error rate (SER) using decode and forward (DF) cooperation and amplify and forward (AF) cooperation are presented respectively when the common channel interference exists. Simulation results demonstrate that the performance based on DF cooperation is better than the performance based on AF cooperation when directional transmission is used.

The Phylotype of Thermus from the Rehai Geothermal Area, Tengchong, China

Guo, Chunlei,Wang, Tao,Zhu, Wei,Zhang, Donghua,Cui, Xiaolong,Xu, Lihua,Peng, Qian The Microbiological Society of Korea 2003 The journal of microbiology Vol.41 No.2

Through enrichment on two nutrient agars, 57 Thermus isolates were recovered from 15 hot spring samples taken from the Rehai geothermal area, Tengchong, China. Unique growth characteristics were observed when the strains were transferred from YIM14 medium to Thermus medium. Phylogenetic analysis showed that the 16S rDNA sequences of the isolates and clones from the Rehai geothermal area farmed a monophyletic group on the phylogenetic tree. A secondary structure comparison showed that their 16S rRNAs have unique secondary structure characteristics.

Modeling and Analysis of a Novel Two-Axis Rotary Electromagnetic Actuator for Fast Steering Mirror

Yongjun Long,Chunlei Wang,Xin Dai,Xiaohui Wei,Shigang Wang 한국자기학회 2014 Journal of Magnetics Vol.19 No.2

This paper focuses on the modeling and analysis a novel two-axis rotary normal-stress electromagnetic actuator with compact structure for fast steering mirror (FSM). The actuator has high force density similar to a solenoid, but its torque output is nearly a linear function of both its driving current and rotation angle, showing that the actuator is ideal for FSM. In addition, the actuator is designed with a new cross topology armature and no additional axial force is generated when the actuator works. With flux leakage being involved in the actuator modeling properly, an accurate analytical model of the actuator, which shows the actuator’s linear characteristics, is obtained via the commonly used equivalent magnetic circuit method. Finally, numerical simulation is presented to validate the analytical actuator model. It is shown that the analytical results are in a good agreement with the simulation results.

Experimental Study on Cracking Behaviour of Intermittent Double S-shaped Fissures under Uniaxial Compression

Qianqian Dong,Chengwang Xiong,Chunlei Ma,Huajian Wei 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.6

Extensive efforts have been made in the understanding of the failure characteristics of straight fissure, but the failure patterns of rock mass with intermittent non-straight fissures have not been examined comprehensively. To address this problem, the present study investigated the cracking behaviors of natural marble specimens containing double S-shaped fissures under compression. Seven types of coalescence patterns for S-shaped fissures are classified, two of which are firstly reported and featured by the occurrence of the self-coalescence phenomenon. It is found that the decrease of strength is accompanied by the internal crack at the stage of crack growth and propagation, following the occurrence of the external crack, at relatively large flaw and ligament angle. The numerical simulations with the corresponding parameters were carried out for comparison. This research provides helpful information for understanding the failure modes induced by crack propagation of intermittent double S-shaped fissures.

Lead ion detection using glutathione-functionalized aluminum gallium nitride/gallium nitride high-electron-mobility transistors

Dong Xiaohu,Jiang Xuecheng,Gu Yan,Wei Chunlei,Xie Zhijian,Zhang Qi,Qian Weiying,Zhang Xiangyang,Zhu Chun,Lu Naiyan,Chen Guoqing,Yang Guofeng 한국물리학회 2023 Current Applied Physics Vol.50 No.-

This work presents a new approach for lead ion detection (Pb2+) using an aluminum gallium nitride/gallium nitride (AlGaN/GaN) high-electron-mobility transistor (HEMT) sensor. The AlGaN/GaN HEMT structure of the sensor was realized by functionalizing the gate area with glutathione (GSH). The crystalline and surface qualities of the AlGaN film were measured through X-ray diffraction and atomic force microscopy. The response of the sensor was measured in terms of the source–drain current with varying concentrations of Pb2+ ions at a fixed drain-to-source voltage. The sensitivity of the sensor was 29.3 μA/(mg/L), and it exhibited high selectivity toward Pb2+. The results show that using the GSH-functionalized AlGaN/GaN HEMT sensor is a promising strategy for Pb2+ ion detection.

The Synthesis of Eu³⁺ Doped with TiO₂ Nano-Powder and Application as a Pesticide Sensor

Yao, Fei,Sun, Yang,Tan, Chunlei,Wei, Song,Zhang, Xiaojuan,Hu, Xiaoyun,Fan, Jun Korean Chemical Society 2011 대한화학회지 Vol.55 No.6

Using tetrabutyl titanate as precursor, $Eu^{3+}$ doped $TiO_2$ nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with $Eu^{3+}$ doped $TiO_2$ was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was quenched by chlorpyrifos and the quenching rate constant ($k_q$) was $1.24{\times}10^{11}\;L/mol{\cdot}s$ according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of $TiO_2$ nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (${\Delta}G_{et}$) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of $Eu^{3+}$ doped $TiO_2$ was proportional to chlorpyrifos concentration. The range of detection was $5.0{\times}10^{-10}-2.5{\times}10^{-7}mol/L$ and the election limit ($3{\sigma}$) was $3.2{\times}10^{-11}$ mol/L.

Hydrogen Peroxide is Involved in Salicylic Acid-Induced Adventitious Rooting in Cucumber Under Cadmium Stress

Gong Wenting,Niu Lijuan,Wang Chunlei,Wei Lijuan,Pan Ying,Liao Weibiao 한국식물학회 2022 Journal of Plant Biology Vol.65 No.1

Cadmium (Cd) stress can cause system disorders in plants, affect the absorption of some nutrients. The roles and their relationship of salicylic acid (SA) and hydrogen peroxide (H2O2) in adventitious root formation (ARF) of cucumber (Cucumis sativus L.) under Cd stress were studied. The results showed that the exogenous SA and H2O2 in enhancing ARF in cucumber explants under Cd stress was concentration-dependent, with an optimal biological effect at 0.1 µM SA or 50 µM H2O2. Under Cd stress, SA-induced ARF was significantly reversed by H2O2 scavenger and inhibitor, indicating that endogenous H2O2 may be involved in SA-induced ARF under Cd stress. In addition, endogenous H2O2 levels were also promoted by SA in cucumber explants. The application of SA promoted pectin content and decreased pectin methylesterification degree under Cd stress. Moreover, we founded that SA and SA + H2O2 up-regulated the expression level of CsQUA and CsPME under Cd stress, respectively. However, the application of H2O2 scavenger and inhibitor could significantly reverse the effects of SA on the expression of the above genes. These results suggested that SA might play an important role in ARF in cucumber under Cd stress via enhancing endogenous H2O2 levels.

Design of a Moving-magnet Electromagnetic Actuator for Fast Steering Mirror through Finite Element Simulation Method

Yongjun Long,Jinqiu Mo,Xiaohui Wei,Chunlei Wang,Shigang Wang 한국자기학회 2014 Journal of Magnetics Vol.19 No.3

This paper develops a moving-magnet electromagnetic actuator for fast steering mirror (FSM). The actuator achieves a reasonable compromise between voice coil actuator and piezoelectric actuator. The stroke of the actuator is between the strokes of a piezoelectric actuator and a voice coil actuator, and its force output is a linear function of air gap and excitation current within our FSM travel range. Additionally, the actuator is more reliable than voice coil actuator as the electrical connection in the actuator is static. Analytically modeling the actuator is difficult and time-consuming. Alternatively, numerous finite element simulations are carried out for the actuator analysis and design. According to the design results, a real prototype of the actuator is fabricated. An experimental test system is then built. Using the test system, the force output of the fabricated actuator is evaluated. The test results validate the actuator analysis and design.