Analysis and Optimization of a Novel Dual PM Vernier Machine with Halbach Array

Li Yaokun,Jing Libing 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

In order to further improve the electromagnetic performance of permanent magnet vernier machine, a novel dual permanent magnet vernier machine (DPMVM) is proposed in this paper. The PMs with consequent-pole (CP) structure is embedded in the inner side of the rotor. The PMs are divided into blocks, and each PM is magnetized using the Halbach array. The arrangement has a more obvious magnetic concentration effect, which can significantly reduce the magnetic flux leakage to improve the air gap flux density. The stator side adopts a novel surface-mounted arrangement of permanent magnets for radial magnetization. This arrangement can improve average torque and power factor. The parametric model of the proposed DPMVM with 14 PM pole-pairs and 4 armature winding pole-pairs is established by finite element software. According to the sensitivity analysis of the parameters, the key parameters are optimized by single parameter scanning and response surface analysis, and the structural parameters of the machine are finally determined.

FDI and the Evolution of Directed Technological Progress Bias: New Evidence from Korean Outward Investment

Boye Li,Xiang Li,Yaokun Wu 한국무역학회 2023 Journal of Korea trade Vol.27 No.5

Purpose – Southeast Asia has been the focus of Korea's foreign investment. Korea has been helping developing countries in Southeast Asia achieve economic growth and win‒win cooperation through capital exports. FDI is an important channel for technology diffusion. However, the impact of FDI on the bias of technological progress in the host country is dependent on the host country's own endowment structure and capital–labor factor substitution elasticity. Therefore, the central issue of this paper is to accurately evaluate the impact of Korea's FDI to the four Southeast Asian countries in various industries on their bias of technological progress. Design/methodology – The paper uses macroeconomic data for Korea and four East Asian countries to estimate capital–labor factor elasticities of substitution using nonlinear, seemingly uncorrelated regressions (NLSUR). Then, the biased technological change index (BTCI) is calculated for each country. Finally, panel data analysis is used to explore the impact of Korean FDI in various industries in the four Southeast Asian countries on their own directed technological progress, and a robustness test is conducted. Findings – There is a substitution relationship between capital and labor factors based on their elasticity in Korea, Singapore and the Philippines. There is a complementary relationship between capital and labor factors in Indonesia and Malaysia. According to the BTCI, there is a trend toward labor-biased technological progress in all countries. Korean investments in manufacturing, wholesale and retail trade in the host country trigger capital-biased technological change in the host country; investments in the finance, insurance and information and communication sectors trigger labor- biased technological change. In addition, this paper also confirms that directed technological progress can enable cross-country transmission. Originality/value – The innovation of this paper lies in three aspects. First, we estimate the BTCI for five countries and explore the trend and situation of directed technological progress in each country from each country's own perspective. Second, we explore the impact of Korean FDI in the host country on the bias to its technological progress at the industry level. Second, we explore the impact of Korean FDI in various industries in the four Southeast Asian countries on the four countries' own directed technological progress from a national perspective. Finally, we propose corresponding countermea- sures for technological progress from the perspective of inverse factor endowment. These innovative points not only expand the understanding of technological progress and cross-country technology transfer in East Asia but also provide practical references for policy-makers and business operators.

Effects of a multi-strain probiotic on growth, health, and fecal bacterial flora of neonatal dairy calves

Guo Yongqing,Li Zheng,Deng Ming,Li Yaokun,Liu Guangbin,Liu Dewu,Liu Qihong,Liu Qingshen,Sun Baoli 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.2

Objective: The aim of this study was to investigate the effects of dietary supplementation with a multi-strain probiotic (MSP) product containing of Bifidobacterium animalis, Lactobacillus casei, Streptococcus faecalis, and Bacillus cerevisiae on growth, health, and fecal bacterial composition of dairy calves during the first month of life. Methods: Forty Holstein calves (24 female and 16 male) at 2 d of age were grouped by sex and date of birth then randomly assigned to 1 of 4 treatments: milk replacer supplementation with 0 g (0MSP), 2 g (2MSP), 4 g (4MSP), and 6 g (6MSP) MSP per calf per day. Results: Supplementation of MSP did not result in any significant differences in parameters of body measurements of calves during the 30 d period. As the dosage of MSP increased, the average daily gain (p = 0.025) and total dry matter intake (p = 0.020) of calves showed a linear increase. The fecal consistency index of the 2MSP, 4MSP, and 6MSP group calves were lower than that of the 0MSP group calves (p = 0.003). As the dosage of MSP increased, the concentrations of lactate dehydrogenase (p = 0.068) and aspartate aminotransferase (p = 0.081) in serum tended to decrease, whereas the concentration of total cholesterol increased quadratically (p = 0.021). The relative abundance of Dorea in feces was lower (p = 0.011) in the 2MSP, 4MSP, and 6MSP group calves than that in the 0MSP group calves. The relative abundance of Dorea (p = 0.001), Faecalibacterium (p = 0.050), and Mitsuokella (p = 0.030) decreased linearly, whereas the relative abundance of Prevotella tended to increase linearly as the dosage of MSP increased (p = 0.058). Conclusion: The MSP product can be used to reduce the diarrhea, improve the performance, and alter the composition of the fecal bacteria in neonatal dairy calves under the commercial conditions. Objective: The aim of this study was to investigate the effects of dietary supplementation with a multi-strain probiotic (MSP) product containing of Bifidobacterium animalis, Lactobacillus casei, Streptococcus faecalis, and Bacillus cerevisiae on growth, health, and fecal bacterial composition of dairy calves during the first month of life.Methods: Forty Holstein calves (24 female and 16 male) at 2 d of age were grouped by sex and date of birth then randomly assigned to 1 of 4 treatments: milk replacer supplementation with 0 g (0MSP), 2 g (2MSP), 4 g (4MSP), and 6 g (6MSP) MSP per calf per day.Results: Supplementation of MSP did not result in any significant differences in parameters of body measurements of calves during the 30 d period. As the dosage of MSP increased, the average daily gain (p = 0.025) and total dry matter intake (p = 0.020) of calves showed a linear increase. The fecal consistency index of the 2MSP, 4MSP, and 6MSP group calves were lower than that of the 0MSP group calves (p = 0.003). As the dosage of MSP increased, the concentrations of lactate dehydrogenase (p = 0.068) and aspartate aminotransferase (p = 0.081) in serum tended to decrease, whereas the concentration of total cholesterol increased quadratically (p = 0.021). The relative abundance of Dorea in feces was lower (p = 0.011) in the 2MSP, 4MSP, and 6MSP group calves than that in the 0MSP group calves. The relative abundance of Dorea (p = 0.001), Faecalibacterium (p = 0.050), and Mitsuokella (p = 0.030) decreased linearly, whereas the relative abundance of Prevotella tended to increase linearly as the dosage of MSP increased (p = 0.058).Conclusion: The MSP product can be used to reduce the diarrhea, improve the performance, and alter the composition of the fecal bacteria in neonatal dairy calves under the commercial conditions.

Quantitatively Decoupling the Impact of Preload and Internal Mechanism Motion on Pyrotechnic Separation Shock

Shihui Xiong,Yanhua Li,Yaokun Ye,Jingcheng Wang,Huina Mu,Yuquan Wen 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.5

Pyrotechnic separation devices are widely used in space separation systems. However, these devices produce high-frequency, high-amplitude shock responses during operation, which endangers the safety of space systems. Hence, it is imperative to study the shock mechanism and characteristics during the unlocking process of a pyrotechnic separation device. This paper uses LS-DYNA finite element software and experiments to analyze the separation characteristics of the separation nut and predict its shock response, quantitatively decoupling the impact of preload and internal mechanism motion on separation shock. The results indicate that the shock response caused by the impact on the inner sleeve is the primary contributor to the total shock response of the separation nut (approximately 55% of the total response). The shock response caused by the release of the strain energy is very small, accounting for less than 5% of the total shock response. Adjusting the preload force without changing the charge and structure of the separation device did not have a clear impact on reducing the shock. This study shows that the shock of the separation device can be decreased by reducing the impact on the inner sleeve.