Effect of Shifting the Pole-shoe and Damper-bar Centerlines on the No-load Voltage Waveform of a Tubular Hydro-generator

Fan, Zhen-nan,Han, Li,Liao, Yong,Xie, Li-dan,Wen, Kun,Wang, Jun,Dong, Xiu-cheng,Yao, Bing The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This study optimises the no-load voltage waveform of tubular hydro-generators by a simple design scheme. For different centerlines of the pole shoe and damper bar, the optimisation effects on the no-load voltage waveform are investigated in two tubular hydro-generators with different weighted powers (34 MW and 18 MW). The results are compared with those of the traditional stator-slots skewed design. The quality of the no-load voltage waveform was related to the shifting degree, and the different optimisation effects between the integer slot generator (q = 2) and the fractional slot generator (q = 11/2) were analysed. This research can improve the quality of the power output and no-load voltage waveform, and provide an effective reference for improving the industrial design and manufacture level of tubular hydro-generators.

Identification of mountain-cultivated ginseng and cultivated ginseng using UPLC/oa-TOF MSE with a multivariate statistical sample-profiling strategy

Xu, Xin-fang,Cheng, Xian-long,Lin, Qing-hua,Li, Sha-sha,Jia, Zhe,Han, Ting,Lin, Rui-chao,Wang, Dan,Wei, Feng,Li, Xiang-ri The Korean Society of Ginseng 2016 Journal of Ginseng Research Vol.40 No.4

Background: Mountain-cultivated ginseng (MCG) and cultivated ginseng (CG) both belong to Panax ginseng and have similar ingredients. However, their pharmacological activities are different due to their significantly different growth environments. Methods: An ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS)-based approach was developed to distinguish MCG and CG. Multivariate statistical methods, such as principal component analysis and supervised orthogonal partial-least-squares discrimination analysis were used to select the influential components. Results: Under optimized UPLC-QTOF-MS/MS conditions, 40 ginsenosides in both MCG and CG were unambiguously identified and tentatively assigned. The results showed that the characteristic components of CG and MCG included ginsenoside Ra3/isomer, gypenoside XVII, quinquenoside R1, ginsenoside Ra7, notoginsenoside Fe, ginsenoside Ra2, ginsenoside Rs6/Rs7, malonyl ginsenoside Rc, malonyl ginsenoside Rb1, malonyl ginsenoside Rb2, palmitoleic acid, and ethyl linoleate. The malony ginsenosides are abundant in CG, but higher levels of the minor ginsenosides were detected in MCG. Conclusion: This is the first time that the differences between CG and MCG have been observed systematically at the chemical level. Our results suggested that using the identified characteristic components as chemical markers to identify different ginseng products is effective and viable.

Effect of Shifting the Pole-shoe and Damper-bar Centerlines on the No-load Voltage Waveform of a Tubular Hydro-generator

Zhen-nan Fan,Li Han,Yong Liao,Li-dan Xie,Kun Wen,Jun Wang,Xiu-cheng Dong,Bing Yao 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This study optimises the no-load voltage waveform of tubular hydro-generators by a simple design scheme. For different centerlines of the pole shoe and damper bar, the optimisation effects on the no-load voltage waveform are investigated in two tubular hydro-generators with different weighted powers (34 MW and 18 MW). The results are compared with those of the traditional stator-slots skewed design. The quality of the no-load voltage waveform was related to the shifting degree, and the different optimisation effects between the integer slot generator (q = 2) and the fractional slot generator (q = 11/2) were analysed. This research can improve the quality of the power output and no-load voltage waveform, and provide an effective reference for improving the industrial design and manufacture level of tubular hydro-generators.

355nm 펄스 레이저를 이용한 구리 표면의 소수성 개질에 관한 연구

윤단희,강보석,박준한,곽청렬,신보성,Yun, Dan Hee,Kang, Bo Seok,Park, Jun Han,Gwak, Cheng Yeol,Shin, Bo Sung 한국마이크로전자및패키징학회 2016 마이크로전자 및 패키징학회지 Vol.23 No.4

최근 자연모방을 이용한 소수성 표면 가공이 많은 관심을 끌고 있다. 대표적인 가공 방법으로 기계적 가공, 포토리소그래피 가공, 레이저를 이용한 공정이 있다. 본 논문에서는 구리필름에 UV 펄스 레이저를 직접 조사해 마이크로 그루브를 형성하고 상온에서의 산화를 통해 표면의 거칠기를 증가시켜 소수성 표면을 제작하였다. 패턴 생성 뒤 일정 시간 산화를 시킨 후에 측정된 접촉각은 산화를 시키기 전보다 약 $30{\sim}70^{\circ}$까지 증가함을 보인다. 본 연구 결과를 통해서 화학적인 처리과정 없이 보다 안정한 소수성 표면을 제조할 수 있음을 확인하였다. Recently, the hydrophobic surface has been attracted because of the excellent opto-physical properties. Various processing methods such as chemical, mechanical, photolithographic and laser processing are competitively introduced for fabrication of hydrophobic surface of polymer, metal and ceramics. In this paper, we fabricated the hydrophobic surface of copper metal by simple method which irradiated 355 nm UV-pulsed laser in order to shape microgrooves and increased surface roughness through oxidation process at room temperature. Finally the contact angle is dramatically increased by maximum $45^{\circ}$, as a result of oxidation which simply created nanostructures on the microstructures without expensive chemical process.

Theoretical solutions for displacement and stress of a circular opening reinforced by grouted rock bolt

Zou, Jin-Feng,Xia, Zhang-Qi,Dan, Han-Cheng Techno-Press 2016 Geomechanics & engineering Vol.11 No.3

This paper presented solutions of displacement and stress for a circular opening which is reinforced with grouted rock bolt. It satisfies the Mohr-Coulomb (M-C) or generalized Hoek-Brown (H-B) failure criterion, and exhibits elastic-brittle-plastic or strain-softening behavior. The numerical stepwise produce for strain-softening rock mass reinforced with grouted rock bolt was developed with non-associative flow rules and two segments piecewise linear functions related to a principle strain-dependent plastic parameter, to model the transition from peak to residual strength. Three models of the interaction mechanism between grouted rock bolt and surrounding rock proposed by Fahimifar and Soroush (2005) were adopted. Based on the axial symmetrical plane strain assumption, the theoretical solution of the displacement and stress were proposed for a circular tunnel excavated in elastic-brittle-plastic and strain-softening rock mass compatible with M-C or generalized H-B failure criterion, which is reinforced with grouted rock bolt. It showed that Fahimifar and Soroush's (2005) solution is a special case of the proposed solution for n = 0.5. Further, the proposed method is validated through example comparison calculated by MATLAB programming. Meanwhile, some particular examples for M-C or generalized H-B failure criterion have been conducted, and parametric studies were carried out to highlight the influence of different parameters (e.g., the very good, average and very poor rock mass). The results showed that, stress field in plastic region of surrounding rock with considering the supporting effectiveness of the grouted rock bolt is more than that without considering the effectiveness of the grouted rock bolt, and the convergence and plastic radius are reduced.

Theoretical Solutions for a Circular Opening in an Elastic–brittle–plastic Rock Mass Incorporating the Out-of-plane Stress and Seepage Force

Zou Jin-feng,Li Shuai-shuai,Xu Yuan,Dan Han-cheng,Zhao Lian-heng 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.2

Seepage force is simplified as seepage volumetric force in the stress field along the radial direction. Out-of-plane stress and seepage force are incorporated, and the theoretical solutions for stress, displacement, and plastic radius of a circular opening for the elastic-brittle-plastic and elastic-plastic rock mass are proposed based on the Mohr–Coulomb (MC) and generalized Hoek-Brown (HB) failure criteria. The presented solution and Wang’s solution (2012) are compared, and the corrected version of the proposed method is validated. Numerical examples of the proposed method based on the MC and generalized HB failure criteria reveal that the distributions of stress and displacement in the surrounding rock of the tunnel are significantly influenced by seepage force and out-ofplane stress. Displacement and plastic radius when seepage force and out-of-plane stress are considered are larger than those when the seepage force is not considered; the regulations of stress, however, run opposite. The results of displacement and plastic radius based on the generalized HB failure criterion are larger than those based on the MC failure criterion.