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Dynamic response of curvilinearly stiffened plates under thermal environment
Jingze Liu,Qingguo Fei,Shaoqing Wu,Dahai Zhang,Dong Jiang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6
An improved finite element modeling method is developed for isotropic curvilinearly stiffened plates under a thermal environment. The existing modeling method for curvilinearly stiffened plates avoids the difficulty of node overlap, which is suitable for plates with different thicknesses. By introducing the influence of temperature on material parameters and thermal stress on additional stiffness, the existing method is improved and extended to the study of thermodynamics. The proposed method is verified by modal test at normal temperature and commercial finite element software at the thermal environment. The variation of dynamic characteristics with temperature under different boundary conditions was studied. Results show that when the boundary conditions are asymmetric, the influence of temperature on the thermal mode shape is more significant than the case of symmetrical.
Single-stage LLC AC/DC converter with wide input range and low bus voltage
Gao, Jingxiang,Zhang, Junhong,Zhu, Zhongni,Song, Qingguo The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.1
The traditional single-stage boost LLC resonant AC/DC converter has been widely studied due to advantages such as few power stages, high power factor, and soft switching. However, it also has several disadvantages, such as a low and narrow input voltage, a DC bus voltage that is much higher than the input voltage, and high stress of the switching devices. Therefore, it is generally used in power grids under 110 V. In order to overcome the above problems, this paper proposed a buck-boost LLC resonant AC/DC converter for both 110 V and 220 V power grids. In addition to its traditional structure, the proposed converter has the advantages of a wide input voltage range and a low bus voltage. The proposed converter adopts the PFM-PWM hybrid control strategy. In this paper, the working principle of the proposed converter is analyzed in detail, the realization of the power factor correction mechanism and the soft switching are described, and the design methods of the key parameters are given. Finally, an experimental prototype with a 110 V-250 V input and a 48 V/100 W output is built. Experimental results verify the correctness of the theoretical analysis of the converter and its applicability to power grids.
Solar Plasma Diagnostic for O III Spectral Lines by using the Collision Excitation Model
Jian He,Qingguo Zhang 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.10
In this paper, using the collisions between ions and free electrons, we discuss the conditions for electron collision equilibrium. Using collision excitation and de-excitation, we discuss a method for a solar temperature diagnostic for three-level ions. Taking the O III ion as an example, for the intensity ratio of the (2-1) transition to the (3-2) transition, we calculate the temperature when the intensity ratio varies from 10 to 200, and we obtain some useful conclusions. This discussion is important for solar plasma diagnostic under the conditions of electron collision equilibrium.
Jian He,Qingguo Zhang 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.9
Non-Maxwellian distributions are found in the laboratory and space plasmas. For an accurate study of plasmas, the Kappa-averaged collision strengths of silicon VIII ion for 40S3=2-20D3=2, 40S3=2-20D5=2 and 20D3=2-20D5=2 transitions are calculated for Kappa distributions with = 2, 3 and 5 and for temperatures from 104:5 K to 106:5 K. Results indicate that significant differences occur between the averaged collision strengths for the Maxwellian and the Kappa distributions. Fuythermore, and for each value, the Kappa-averaged collision strengths vary in a complicated way with temperature for the 40S3=2-20D3=2 and 40S3=2-20D5=2 transitions while they decrease with increasing temperature for the 20D3=2-20D5=2 transition. The calculation is significant if plasmas are to be studied for a non-Maxwellian distribution.
Spectral Diagnostic for the Soft X-ray Fe XVII Spectral Line in the Solar Corona
Jian He,Qingguo Zhang,Qiuze Li 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.8
In this paper, taking the soft X-ray Fe XVII 1.501-nm spectral line in the solar corona as an example, we analyze the effect of opacity on the 1.501-nm spectral line, and we discuss the diagnostic principle for the plasma temperature and the electron density. Results show that the plasma temperature in the solar coronal has an order of magnitude of 106 K and that the electron density has an order of magnitude of 1010 cm−3, which are in good agreement with the reported values. Through analysis, we show that the opacity has a great effect on the 1.501-nm spectral line and that the electron density is connected with the temperature. The results of this study are significant and valuable in solar coronal plasma diagnostics.
Temperature Diagnostics for Carbon IV Ion by using a Collision Model in the Solar Transition Region
Lamei Liao,Jian He,Qingguo Zhang 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.5
For spectral diagnostics of temperature in the solar transition region, by using a semi-classical method, we calculate the collision strengths for the dipole transition of carbon IV 2S1/2-2P1/2 and 2S1/2-2P3/2, and we discuss the Maxwellian-averaged collision strengths for a wide temperature region. Then, based on the Maxwellian-averaged collision strengths, we discuss the spectral diagnostic of temperature in the solar transition region and obtain the temperature T = 1.7 × 105 K for the carbon IV ion in that region, which is in good agreement with the predicted temperature range of 1.0 × 105 K to 2.0 × 105 K. This calculation will be significant for spectral diagnostics in the solar transition region.
Jun Liao,Fan Yang,Lei Zhang,Xiaoyun Chai,Qing-Jie Zhao,Shichong Yu,Yan Zou,Qingguo Meng,Qiuye Wu 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.4
A novel series of fluconazole based mimicsincorporating 1,3,4-oxadiazole moiety were designed andsynthesized. All the title compounds were characterized by1H-NMR, 13C-NMR, and Q-TOF-MS. Preliminary resultsrevealed that most of analogues exhibited significant antifungalactivity against seven pathogenic fungi. Compounds9g and 9k (MIC80 B 0.125 lg/mL, respectively) werefound more potent than the positive controls itraconazoleand fluconazole as broad-spectrum antifungal agents. Theobserved docking results showed that the 1,3,4-oxadiazolemoiety enhanced the affinity binding to the cytochromeP450 14a-demethylase (CYP51).
Nonlinear response analysis of variable speed rotor system under maneuvering flight
Xueyang Miao,Junzeng He,Dahai Zhang,Dong Jiang,Jian Li,Xing Ai,Qingguo Fei 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10
Maneuverability is one of the important tactical and technical indexes of fighter aircraft. In this paper, the finite element method is used to establish a dynamic model of the rotor system that can consider arbitrary maneuvering flight form and rotor speed variation during the flight, and the vibration characteristic of the dynamic model is investigated in detail. In addition, the nonlinear forces caused by bearings and oil film are also considered. The Newmark-β method combined with Newton-Raphson method is adopted to solve the dynamic equations. The influences of speed variation, rolling, pitching, and yawing maneuver loads on the vibration responses of the rotor system are also evaluated.
Discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins
Juan Liu,Yangrong Xu,Jingjing Yang,Wenzhi Wang,Jianqiang Zhang,Renmei Zhang,Qingguo Meng 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3
Ocotillol-type saponins are one kind of tetracyclic triterpenoids, sharing a tetrahydrofuran ring. Natural ocotillol-type saponins have been discovered in Panax quinquefolius L., Panax japonicus, Hana mina, and Vietnamese ginseng. In recent years, the semisynthesis of 20(S/R)-ocotillol-type saponins has been reported. The biological activities of ocotillol-type saponins include neuroprotective effect, antimyocardial ischemia, antiinflammatory, antibacterial, and antitumor activities. Owing to their chemical structure, pharmacological actions, and the stereoselective activity on antimyocardial ischemia, ocotillol-type saponins are subjected to extensive consideration. In this review, we sum up the discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins.