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 : Gensheng (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Simulation of the hydraulic isolation efficiency during multistage hydrajet fracturing
Xin Fan,Gensheng Li,Zhongwei Huang,Shouceng Tian,Xianzhi Song,Chen Yang 한국자원공학회 2015 Geosystem engineering Vol.18 No.5
Effective isolation between target zones is critical to multistage fracturing. Low pressure zone caused by the hydrajet is used to isolate stages in the multistage hydrajet fracturing technology. However, there are few researches available in the literature that investigates the hydraulic isolation efficiency considering the existence of multiple fractures. This paper builds a three-dimensional computational-fluid-dynamics model with FLUENT software to study the flow field along annular sections under different conditions. It is verified that the results obtained from the model are consistent with experimental data along the perforation tunnel. The mass flow rate ratio between two outlets is proposed to analyze the hydraulic isolation efficiency in hydrajet multistage fracturing. The results show that annular fluid converges into the perforation tunnel due to the high-speed hydrajet even though there is a pre-existing fracture behind. Effective hydraulic isolation can be generated by reducing the pressure differences between target zones and the annular injection velocity as well as by enlarging the jet velocity and the area ratio. It is found that there exists an optimum area ratio to get the maximum isolation efficiency. Sensitivity analysis indicates the pressure difference is the dominant factor affecting the hydraulic isolation efficiency. A fully quadratic model derived from the response surface method is presented to predict the hydraulic isolation efficiency for real fracturing. This study will be able to provide practical guidance for the optimization of hydrajet multistage fracturing.
-
Dual-side Event-triggered Output Feedback H∞ Control for NCS with Communication Delays
Fuqiang Li,Lisai Gao,Gensheng Dou,Baozhou Zheng 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.1
This paper studies the dual-side event-triggered output feedback H∞ control for networked control systemwith network-induced delays. Unlike continuous-time event-triggered mechanism (ETM) or state-dependent ETM,the discrete dual-side ETMs are firstly proposed by using plant output and controller output, respectively, whicheffectively reduce transmission rate of sampled data in both sensor-to-controller and controller-to-actuator channels. Then, the closed-loop system is modelled as a time-delay system, which characterizes effects of the dual-sideETMs and networked-induced delays in a unified framework. Based on the system model, asymptotic stabilitycriterion satisfying H∞ performance is derived, and conservatism is reduced by the delay decomposition methodand reciprocally convex approach. Moreover, a co-design scheme is presented to design the dual-side ETMs andcontroller simultaneously, which is more convenient than two-step design method requiring controllers to be givena priori. Finally, examples confirm effectiveness of the proposed method.
-
Zhimin Ou,Qingmei Chen,Gensheng Yang,Li Xu 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2
Ethyl (S)-3-hydroxy-3-phenylpropionate was synthesized by asymmetric reduction of 3-oxo-3-phenylpropionic acid ethyl ester with undifferentiated cells of white turnip in phosphate buffer/organic solvent. The conversion increased with the LogP_oct of organic solvent increase. The phosphate buffer (0.2 mol/L, pH 7.0)/dodecane was selected as optimum medium for reduction. The optimal content of dodecane in medium is 10% (v). The conversion decreased with initial substrate concentration increase. Addition of more biomass of plant cells and 10% ethanol as co-substrate can improve conversion. The plant cells can be reused well for three times. The enantiomeric excess of ethyl (S)-3-hydroxy-3-phenylpropionate reached 100% with 1% allyl bromide as inhibitor.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
