http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Lifeng Cheng (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
Shuting Wan,Lifeng Cheng,Xiaoling Sheng 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2
The effects of wind shear and the tower shadow contribute to periodic fluctuations in the wind speed and aerodynamic torque, which cause several problems. This study develops an equivalent wind speed model for large-scale, n-bladed wind turbines that includes the wind shear and the tower shadow effects. The comprehensive model is used to derive the disturbance components of wind speed caused by wind shear, the tower shadow, their synthesis, and the equivalent wind speed and to delineate their spatial distributions in the rotor disk area. Simulation results reveal that the effects of wind shear, the tower shadow, and the equivalent wind speed on the disturbance components fluctuate periodically and are closely related to the wind turbine correlation parameters, such as the rotor radius, hub center height, tower radius, distance from the tower midline to the blade, wind shear exponent, and blade number.
-
Xiaoling Sheng,Shuting Wan,Lifeng Cheng,Yonggang Li 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10
The blade aerodynamic asymmetry fault must be detected early due to its important effect on wind turbines. This paper develops a fault diagnosis approach based on the current and power characteristics of a Doubly fed induction generator (DFIG). First, the blade aerodynamic characteristics and the influence on the nacelle and tower vibration under an aerodynamic asymmetry fault are analysed and an improved Blade element moment (BEM) method considering the blade, nacelle and tower vibration is proposed to calculate the aerodynamic torque. Then, the electrical characteristics of the DFIG are analysed. The output power is shown to decrease with oscillation when aerodynamic asymmetry occurs. In addition, the same modulation harmonic frequency as the blade rotating frequency exists in the stator and the rotor current. Finally, simulations under constant and stochastic wind conditions via MATLAB/Simulink show the effectiveness of the proposed method in this paper.
-
Engineering of a Bacillus subtilis Strain Deficient in Cellulase: Application in Degumming of Ramie
Qi Yang,Shengwen Duan,Lifeng Cheng,Xiangyuan Feng,Ke Zheng,Chunliang Xie,Zhiyuan Liu,Yuande Peng 한국섬유공학회 2019 Fibers and polymers Vol.20 No.1
Degumming is the most important step before ramie fibers are used in textile industry. Conventional chemical degumming technology with alkaline treatment at high temperature causes critical problems in environment. In addition to multiple degumming enzymes (e.g. pectinases and xylanases), Bacillus subtilis strain 168 can also produce cellulase which brings irreversible damage to ramie fibers. In this study, a strain deficient in cellulase was constructed by insertional inactivation of gene eglS to make it suitable for microbial degumming. Results showed that the cellulase activity was not detected in strain ΔeglS, after 25 h of incubation with strain ΔeglS, the weight loss of the ramie fibers was 20.20 %. Though the residual gum content of ramie fibers obtained in microbial degumming process was 19.67 %, microbial intervention followed by diluted alkaline solution treatment showed lower residual gum content (2.73 %) than chemical degumming (2.96 %). The single fiber breaking strength value of ramie fibers from bio-chemical degumming process reached 27.19 cN, which was the highest of three samples. Moreover, bio-chemical degumming process resulted in a 75 % decrease of alkali dosage as compared with chemical degumming process. This study provides a suggestion to genetically modify wild-type strain in order to protect ramie fibers from cellulase damage, and indicates a sustainable alternative for the traditional chemical degumming in the textile industry.
-
Sphingobacterium bambusae sp. nov., Isolated from Soil of Bamboo Plantation
Shengwen Duan,Zhengchu Liu,Xiangyuan Feng,Ke Zheng,Lifeng Cheng 한국미생물학회 2009 The journal of microbiology Vol.47 No.6
A Gram-negative, non-motile, non-spore-forming bacterial strain designated IBFC2009T was isolated from soil of a bamboo plantation. The strain could grow at 11°C~39°C, pH 6.0~9.0, and in the presence of 0~5% NaCl. Based on 16S rRNA gene sequence analysis, Strain IBFC2009T belonged to the genus Sphingobacterium and showed the highest sequence similarity of 94.6% (S. composti T5-12T) with the type strains within the genus. The major fatty acids were summed feature 3 (iso-C15:0 2-OH and/or C16:1 ω7c, 34.4%), iso-C15:0 (22.4%), C16:0 3-OH (15.2%), and iso-C17:0 3-OH (12.8%). The G+C content of the genomic DNA was 41.0 mol%. According to the phenotypic and genotypic characteristics, Strain IBFC2009T should represent a novel species of the genus Sphingobacterium, for which the name Sphingobacterium bambusae sp. nov. is proposed. The type strain is IBFC2009T (=CCTCC AB 209162T =KCTC 22814T).
-
Tunable random lasing behavior in plasmonic nanostructures
Yadav Ashish,Zhong Liubiao,Sun Jun,Jiang Lin,Cheng Gary J.,Chi Lifeng 나노기술연구협의회 2017 Nano Convergence Vol.4 No.1
Random lasing is desired in plasmonics nanostructures through surface plasmon amplification. In this study, tunable random lasing behavior was observed in dye molecules attached with Au nanorods (NRs), Au nanoparticles (NPs) and Au@Ag nanorods (NRs) respectively. Our experimental investigations showed that all nanostructures i.e., Au@AgNRs, AuNRs & AuNPs have intensive tunable spectral effects. The random lasing has been observed at excitation wavelength 532 nm and varying pump powers. The best random lasing properties were noticed in Au@AgNRs structure, which exhibits broad absorption spectrum, sufficiently overlapping with that of dye Rhodamine B (RhB). Au@AgNRs significantly enhance the tunable spectral behavior through localized electromagnetic field and scattering. The random lasing in Au@AgNRs provides an efficient coherent feedback for random lasers.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
