http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
가스터빈엔진 기반 하이브리드 전기동력 추진 시스템 연구개발 동향
임병준(Byeung Jun Lim),전상욱(Sangook Jun),박부민(Pu min Park),김재환(Jae-Hwan Kim) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
배기가스 규제와 배터리, 모터와 같은 전기 관련 기술의 발달로 항공기도 전기 추진 기술이 적용되고 있다. 하지만 승객을 태우고 도시 간 이동이 가능한 비행을 하기에는 순수 전기만으로 아직 어려움이 있어 기존의 가스터빈엔진과 함께 사용하는 추진 시스템이 그 대안으로 떠오르고 있다. 이들 시스템을 하이브리드 혹은 터보일렉트릭 추진 시스템이라고 부르며, 본 논문에서는 이들 동향에 대해 기술하고자 한다. Electric propulsion system has also been applied to aircraft due to exhaust gas regulation and the development of electric technology such as batteries, motors and so on. However, it is still difficult to fly with passengers between cities using all electric propulsion, and so an electric propulsion system with gas turbine engine is emerging an alternative. These systems are called hybrid or turboelectric propulsion system, and this paper describes a review of research and development trends about them.
Jun-Yao He,Pu Wang,Yu-Fen Yang,Song-Lin Xie 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.5
A hydrophilic ionic liquid, 1-butyl-3-methylimidazolium (L)-lactate ([bmim][lactate]), was successfully employed as a co-solvent to improve the biodehydrogenation of steroid 11β-hydroxyl medroxyprogesterone (HMP)to pregna-1,4-diene-6α-methyl-3,20-dione-11β,17α-dihydroxy (PDMDD) in an aqueous-organic biphasic system using Arthrobacter simplex UR106 cells. First, a suitable biphasic system was constituted, composed of toluene and Tris-HCl buffer (0.05 mol/L, pH 7.6) at a 0.4 (V_(org)/V_(aq))volumetric phase ratio. Investigation of biodehydrogenation with the addition of [bmim][lactate] to the aqueous phase was then performed. The results demonstrate that biodehydrogenation is more efficient in a biphasic system containing 2% [bmim][lactate] as a co-solvent compared to an aqueous-toluene two-phase system. Higher bioconversion (83.2% versus 56.4%) was observed after 16 h at a substrate concentration of 80 mg HMP in 8 mL of toluene.
Jun-Gi Jo,Jong-Ho Lee,Dojin Park,Young Gun Pu,Sung-Cheol Shin,Kang-Yoon Lee,Sung-Eon Park,Suk-Joong Lee,Changsik Yoo IEEE 2009 IEEE transactions on microwave theory and techniqu Vol.57 No.4
<P>A dual-mode RF receiver with low-IF architecture has been developed for <I>L</I>1-band Global Positioning System (GPS) and Galileo system in a 0.18- mum CMOS process. The channel-selecting bandpass filter centered at 4.092 MHz has programmable bandwidth (2.046 MHz, 4.092 MHz), which allows the reception of GPS and Galileo signals. A fractional-N phase-locked loop generates the local oscillator signals, which allows multiple reference clock frequencies, and in turn, share of a reference oscillator with other systems. The noise figure of the receiver is 4.5 dB, while consuming 41.4 mW from a 1.8-V supply. The image signal is rejected by more than 34 dB.</P>
Pu Bo Li,Ti Jun Chen,Su Qing Zhang 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.1
The present investigation addresses a new technology, named powder thixoforming, used to fabricate SiCp/ 2024 Al-based composites. The effects of reheating time on microstructure and mechanical properties have been studied. The results indicated that the quantity of liquid, the coarsening behavior of the primary particles, the subsequent plastic deformation occurring during thixoforging, and thus the resulting microstructural compactness and mechanical properties changed as a function of reheating time. The best comprehensive tensile properties of the composite, that is an ultimate tensile strength of 370 MPa and an elongation of 4.4%, were obtained after reheating for 80 min at 625 °C, which was an increase of 23.3% and a decrease of 57.7%, respectively, compared to the 2024 alloy thixoforged under the same conditions as the composite. The fracturing in the composites occurred through interconnecting cracked SiCp and debonded SiC/Al interfaces caused by a higher concentration of stress and a coalescence of microvoids.
Full speed range position‑sensorless compound control scheme for PMSMs
Pu Liu,Di Liu,Yongpeng Shen,Ankang Liu,Xiaoliang Yang,Jun Zhao 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8
At low speeds, a high frequency signal injection method for the position-sensorless control of permanent magnet synchronous motors (PMSMs) produces additional power loss and position estimation delay. Meanwhile, at high speeds, the sliding mode observer (SMO) method has a chattering problem. With a focus on these problems, a full speed range position-sensorless compound control approach is proposed in this paper. First, the phase relationship between the different coordinate systems of the I/F control, and the mechanism of the chattering phenomenon of a sliding mode observer are analyzed. Then the full speed range position-sensorless control approach based on a combination of I/F control and an extended sliding mode observer is constructed. Through feeding back the estimated back electromotive force to the calculation of the stator current observer and using the rotated influence immune phase-locked loop, the innovative extended-SMO effectively improves the chattering phenomenon. Furthermore, the smooth transition between the two control schemes is achieved by a current slope decrement switching controller. Finally, the effectiveness of the proposed full speed range position-sensorless compound control approach for PMSMs is validated on a surface PMSM experimental bench.
Mao-pu Xia,Hai-bo Li,Nan Jiang,Jun-lin Chen,Jia-wen Zhou 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1
Rockfall is a major geological disaster that frequently occurs on rock slopes in alpine and gorge regions and poses a significant threat to life and property in areas exposed to rockfall hazards. In this study, a methodology is presented for comprehensive rockfall hazard analysis, including data acquisition, source identification, numerical simulation, quantitative assessment and mitigation evaluation. A high-precision and high-resolution digital terrain model (DTM) is generated based on the point cloud data obtained by terrestrial laser scanning (TLS) and is utilized for rockfall simulation and automatic identification of structural planes. The model parameters are calibrated by three-dimensional (3D) back analysis, and the rockfall motion is simulated based on a probabilistic model and an energy dissipation model. Rockfall mitigation under passive protection is evaluated according to the rockfall interception ratio (RIR), hazard reduction rate (HRR) and statistics of the rockfall characteristics and hazards within the rockfall threat area. Under the influence of construction excavation, the diversion tunnel inlet slope of Jinchuan Hydropower Station has suffered from a series of rockfall events and potential overall instability, which has become a great threat to the construction personnel, equipment and vehicles below the slope. Thus, the presented methodology is applied to thoroughly study the example case of the rockfall events at the inlet slope of the diversion tunnel of Jinchuan Hydropower Station. The advantages, limitations and notes of each link of the presented methodology are discussed, and the suggestion of strengthening the cracked area with integral active support is proposed.
The Analysis of Golf Participation Behavior based on the Influence of Reference Group in China
Zhou, Pu,Cho, Sang-Woo,Song, Hui-Min,Kim, Sung-Jun 한국골프학회 2017 골프연구 Vol.11 No.2
[목적] 본 연구는 중국인들의 골프참여 행동에 관한 구조관계를 분석하여 중국의 골프 참여인구증진에 필요한 기 초자료를 제공하고자 하였다. [방법] 본 연구대상자는 중국의 심천, 광저우, 하먼시에 소재하는 12개의 골프장과 연습장 이용객 570명을 대상으로 2014년 10월부터 12월까지 설문조사를 실시하여 유효표본 519명을 본 연구자료 로 사용하였다. 자료처리방법으로는 적합성 분석, 공분산분석, 그리고 AMOS(구조 방정식 모형) 통계방법을 이용 하여 골프참여 행동에 대한 영향력을 규명하였다. [결과] 준거집단은 사회적 요인의 영향을 받아 골프참여 행동의 결정에 영향을 주는 것으로, 준거집단의 정보 및 실용적인 측면 또한 중국인들의 골프참여 행동에 유의한 영향을 미치는 것으로 나타났다, 그러나 표현가치 행동 측면은 중국인들의 골프참여 행동에 영향을 미치지 않는 것으로 나타났다. [결론] 골프 참여 행동은 사회적 요인에 영향을 받으며, 긍정적인 정보는 참여에 대한 열정을 높이는데 도움이 된다. [Purpose] The article used literature analysis and structural equation model to build the hypothesis structure about reference group and the golf participation behavior in China. [Method] A total of 570 questionnaires were released in 12 golf courses and driving ranges in Shenzhen, Guangzhou and Xiamen From October to December in 2014, and 519 valid questionnaires were returned. Questionnaires were used to obtain first-hand data, while Good-Of-Fit Analysis, Covariance Analysis and AMOS were used to analysis the influence degree among various dimensions of the reference group to golf participation behavior. [Result] The results showed that reference group affected the decisions of golf participation behavior in China, and the information and utilitarian aspects in reference groups significantly affected the golf participation behavior in China, while the expression value act had no effect on Chinese golf participation behavior. [Conclusion] In conclusion, golf participation behavior influenced by social factors, and positive information offered also helps to increase the enthusiasm of participation.