Loss Analysis and Air-Cooled Design for a Cascaded Electrical Source Transmitter

Kai-chang Xue,Shuang Wang,Jun Lin,Gang Li,Feng-dao Zhou 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

Air-cooling method is adopted on the basis of the requirements for the thermal stability and convenient field use of an electrical source transmitter. The power losses of the transmitter are determined after calculating the losses of the alternating current (AC)?direct current (DC) power supply, the constant-current circuit, and the output circuit. According to the analysis of the characteristics of a heat sink with striped fins and a fan, the engineering calculation expression of the Nusselt number and the design process for air-cooled dissipation are proposed. Experimental results verify that the error between calculated and measured values of the transmitter losses is 12.2%, which meets the error design requirements of less than 25%. Steady-state average temperature rise of the heat sink of the AC?DC power supply is 22 °C, which meets the design requirements of a temperature rise between 20 °C and 40 °C. The transmitter has favorable thermal stability with 40 kW output power.

A study on a flutter wind energy harvesting system about the performance of different streamlined bodies

Kai Xue,Jong-won Seok 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

A study on a two-degree-of-freedom wind energy harvester based on flutter phenomenon

Kai Xue,Jong-won Seok 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.5

Loss Analysis and Air-Cooled Design for a Cascaded Electrical Source Transmitter

Xue, Kai-Chang,Wang, Shuang,Lin, Jun,Li, Gang,Zhou, Feng-Dao The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

Air-cooling method is adopted on the basis of the requirements for the thermal stability and convenient field use of an electrical source transmitter. The power losses of the transmitter are determined after calculating the losses of the alternating current (AC)-direct current (DC) power supply, the constant-current circuit, and the output circuit. According to the analysis of the characteristics of a heat sink with striped fins and a fan, the engineering calculation expression of the Nusselt number and the design process for air-cooled dissipation are proposed. Experimental results verify that the error between calculated and measured values of the transmitter losses is 12.2%, which meets the error design requirements of less than 25%. Steady-state average temperature rise of the heat sink of the AC-DC power supply is $22^{\circ}C$, which meets the design requirements of a temperature rise between $20^{\circ}C$ and $40^{\circ}C$. The transmitter has favorable thermal stability with 40 kW output power.

From Conflict Avoidance to Peaceful Path: The US-DPRK Denuclearization Interaction under the Frame of Incomplete Information Game

Xue Rui Kai,Xue Xin Guo 한국학술연구원 2022 Korea Observer Vol.53 No.1

The North Korean nuclear crisis is not only a major security issue but also a defense strategic issue as well. Whatever future U.S. policy toward North Korea, the game between the two countries will have to figure out what kind of Pyongyang Washington is dealing with. Starting from the extreme hypothesis that the United States may take a military strike against the DPRK, this article creatively constructs the game model of incomplete information between the U.S. and the DPRK, and establishes the payoff matrix for two types of the DPRK: tough and weak. Then, the article tries to answer why the United States does not have the conditions for military strikes against North Korea through the analysis of different payoffs of the United States towards the DPRK. Also, North Korea's tactics at the negotiating table, as well as the trends of US-DPRK relations, are important and will be analyzed in the article.

Experimental research on seismic behavior of SRC-RC transfer columns

Kai Wu,Jianyang Xue,Yang Nan,Hongtie Zhao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.1

It was found that the lateral stiffness changes obvious at the transfer position of the section configuration from SRC to RC. This particular behavior leads to that the transfer columns become as the important elements in SRC-RC hybrid structures. A comprehensive study was conducted to investigate the seismic behavior of SRC-RC transfer columns based on a low cyclic loading test of 16 transfer columns compared with 1 RC column. Test results shows three failure modes for transfer columns, which are shear failure, bond failure and bend failure. Its seismic behavior was completely analyzed about the failure mode, hysteretic and skeleton curves, bearing capacity deformation ability, stiffness degradation and energy dissipation. It is further determined that displacement ductility coefficient of transfer columns changes from 1.97 to 5.99. The stiffness of transfer columns are at the interval of SRC and RC, and hence transfer columns can play the role of transition from SRC to RC. All specimens show similar discipline of stiffness degradation and the process can be divided into three parts. Some specimens of transfer column lose bearing capacity swiftly after shear cracking and showed weak energy dissipation ability, but the others show better ability of energy dissipation than RC column.

PARALLEL IMAGE RECONSTRUCTION FOR NEW VACUUM SOLAR TELESCOPE

Xue-Bao Li,Feng Wang,Yong Yuan Xiang,Yan-Fang Zheng,Ying Bo Liu,Hui Deng,Kai-fan Ji 한국천문학회 2014 Journal of The Korean Astronomical Society Vol.47 No.2

Many advanced ground-based solar telescopes improve the spatial resolution of observation images using an adaptive optics (AO) system. As any AO correction remains only partial, it is necessary to use post-processing image reconstruction techniques such as speckle masking or shift-and-add (SAA) to reconstruct a high-spatial-resolution image from atmospherically degraded solar images. In the New Vacuum Solar Telescope (NVST), the spatial resolution in solar images is improved by frame selection and SAA. In order to overcome the burden of massive speckle data processing, we investigate the possibility of using the speckle reconstruction program in a real-time application at the telescope site. The code has been written in the C programming language and optimized for parallel processing in a multi-processor environment. We analyze the scalability of the code to identify possible bottlenecks, and we conclude that the presented code is capable of being run in real-time reconstruction applications at NVST and future large aperture solar telescopes if care is taken that the multi-processor environment has low latencies between the computation nodes.

Bioactivity of essential oil of Litsea cubeba from China and its main compounds against two stored product insects

Kai Yang,Cheng FangWang,Chun Xue You,Zhu Feng Geng,Rui Qi Sun,Shan Shan Guo,Shu Shan Du,Zhi Long Liu,Zhi Wei Deng 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

During our screening program for agrochemicals from Chinese medicinal herbs and wild plants, the essential oilof Litsea cubeba fruits was found to possess strong contact toxicity against the cigarette beetle Lasiodermaserricorne adults and the booklouse Liposcelis bostrychophila, with LD50 values of 27.33 μg/adult and71.56 μg/cm2, respectively, and also showed strong fumigant toxicity against the two stored product insectswith LC50 values of 22.97 and 0.73 mg/L, respectively. The essential oil obtained by hydrodistillation wasinvestigated by GC MS. The main components of the essential oil were identified to be E-citral (geranial)(27.49%), Z-citral (neral) (23.57%) and D-limonene (18.82%) followed by β-thujene (3.34%), β-pinene (2.85%), α-pinene (2.57%), 6-methyl-5-hepten-2-one (2.40%) and linalool (2.36%). Citral (Z/E-citral), D-limonene, β-pinene,α-pinene and linalool were separated and purified by silica gel column chromatography and preparative thinlayer chromatography, and further identified by means of physicochemical and spectrometric analysis. Citral andlinalool showed strong contact toxicity against L. serricorne and L. bostrychophila (LD50 = 11.76, 12.74 μg/adultand 20.15, 99.97 μg/cm2, respectively) and fumigant toxicity against L. serricorne and L. bostrychophila (16.54,18.04 mg/L air and 0.14, 0.71 mg/L air, respectively). Otherwise, citral, D-limonene and linalool were strongly repellentagainst the cigarette beetle L. serricorne as the essential oil whereas β-pinene and α-pinene exhibited weakerrepellency against the cigarette beetle compared with the positive control, DEET. Moreover, except α-pinene andlinalool, the other three compounds as well as the essential oil exhibited comparable repellency against thebooklouse relative to DEET.

Experimental study on shear damage and lateral stiffness of transfer column in SRC-RC hybrid structure

Kai Wu,Jiangpeng Zhai,Jianyang Xue,Fangyuan Xu,Hongtie Zhao 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.23 No.5

A low-cycle loading experiment of 16 transfer column specimens was conducted to study the influence of parameters, likes the extension length of shape steel, the ratio of shape steel, the axial compression ratio and the volumetric ratio of stirrups, on the shear distribution between steel and concrete, the concrete damage state and the degradation of lateral stiffness. Shear force of shape steel reacted at the core area of concrete section and led to tension effect which accelerated the damage of concrete. At the same time, the damage of concrete diminished its shear capacity and resulted in the shear enlargement of shape steel. The interplay between concrete damage and shear force of shape steel ultimately made for the failures of transfer columns. With the increase of extension length, the lateral stiffness first increases and then decreases, but the stiffness degradation gets faster; With the increase of steel ratio, the lateral stiffness remains the same, but the degradation gets faster; With the increase of the axial compression ratio, the lateral stiffness increases, and the degradation is more significant. Using more stirrups can effectively restrain the development of cracks and increase the lateral stiffness at the yielding point. Also, a formula for calculating the yielding lateral stiffness is obtained by a regression analysis of the test data.

The Effect of Transformation on the Virulence of Streptococcus pneumoniae

Xue-Mei Zhang,Yi-Bing Yin,Dan Zhu,Bao-De Chen,Jin-Yong Luo,Yi-Ping Deng,Ming-Fang Liu,Shu-Hui Chen,Jiang-Ping Meng,Kai Lan,Yuan-Shuai Huang,Ge-Fei Kang 한국미생물학회 2005 The journal of microbiology Vol.43 No.4

Although pneumococcus is one of the most frequently encountered opportunistic pathogen in the world, the mechanisms responsible for its infectiveness have not yet been fully understood. In this paper, we have attempted to characterize the effects of pneumococcal transformation on the pathogenesis of the organism. We constructed three transformation-deficient pneumococcal strains, which were designated as Nos. 1d, 2d, and 22d. The construction of these altered strains was achieved via the insertion of the inactivated gene, comE, to strains 1, 2 and 22. We then conducted a comparison between the virulence of the transformation-deficient strains and that of the wild-type strains, via an evaluation of the ability of each strain to adhere to endothelial cells, and also assessed psaA mRNA expression, and the survival of hosts after bacterial challenge. Compared to what was observed with the wild-type strains, our results indicated that the ability of all of the transformation-deficient strains to adhere to the ECV304 cells had been significantly reduced (p < 0.05), the expression of psaA mRNA was reduced significantly (p < 0.05) in strains 2d and 22d, and the median survival time of mice infected with strains 1d and 2d was increased significantly after intraperitoneal bacterial challenge (p < 0.05). The results of our study also clearly indicated that transformation exerts significant effects on the virulence characteristics of S. pneumoniae, although the degree to which this effect is noted appears to depend primarily on the genetic background of the bacteria.