Results 81 to 90 of about 14,048 (222)

Customized Design and Application of High ROP Bit for Deep Shale Gas

Shiyou jixie
As the development scale of shale gas expands， improving the rate of penetration （ROP） of deep shale gas has become the key to improving development efficiency， and designing more targeted bit based on formation characteristics is an effective means to ...
Zhu Xiaohua, Deng Kaichuang, Liu Weiji, Li Ke, Li Yuanjun, Chen Wei, Yan Juntao   +6 more
doaj   +3 more sources

Study on the Wear Law of PDC Bits in Conglomerate

Shiyou jixie, 2020
A simplified model of dual-cutter PDC bits was established to model how the PDC bit is being worn when drilling into dense conglomerate. Then the rock breaking process was investigated using an Archard wear model and finite element software, and how the ...
Huang Peng, Guan Feng, Zheng Liwei, Wang Lili, Yang Minghe   +4 more
doaj  

One-step error correction for multipartite polarization entanglement

, 2011
We present two economical one-step error-correction protocols for multipartite polarization-entangled systems in a Greenberger-Horne-Zeilinger state. One uses spatial entanglement to correct errors in the polarization entanglement of an N-photon system ...
Fu-Guo Deng, M. A. Nielsen
core   +1 more source

Optimization Design Method of PDC Bit Based on Impact Failure Mechanism

Shiyou jixie
To enhance the anti-failure capability of PDC bits and extend bit service life， the main impact characteristics of PDC cutters in different regions of the bit were investigated.
Shi Jiangang Liu Yingbiao Xi Chuanming Guo Yong Wu Desheng
doaj  

Study on Mechanism of Stick–Slip Vibration Based on Torque Characteristics of PDC Bit

Applied Sciences
Stick–slip vibration (SV) of drill string systems is the main cause of fatigue failure of PDC bits under complex drilling conditions. Exploring its mechanism is helpful for identifying the causes of bit failure and developing preventive measures to ...
Lijun Li, Chunliang Zhang, Aixuan Wu
doaj   +1 more source

Implementation of the Sun Position Calculation in the PDC-1 Control Microprocessor [PDF]

, 1984
The several computational approaches to providing the local azimuth and elevation angles of the Sun as a function of local time and then the utilization of the most appropriate method in the PDC-1 microprocessor are presented.
Stallkamp, J. A.
core   +1 more source

GHz QKD at telecom wavelengths using up-conversion detectors

, 2005
We have developed a hybrid single photon detection scheme for telecom wavelengths based on nonlinear sum-frequency generation and silicon single-photon avalanche diodes (SPADs).
, A Rochas, Bennett C H, Bennett C H Brassard G, De Micheli M P, Ghioni M, H Zbinden, I Rech, Keller U, L Krainer, Lacaita A, N Gisin, R T Thew, S C Zeller, S Cova, S Tanzilli, Sutherland R L, Takesue H, Temporão G, Townsend P D   +19 more
core   +2 more sources

Research and Application of Ridged Diamond Element Bit

Shiyou jixie, 2018
To address the problems of cylindrical PDC cutters like thermal wear, impact damage and balling and the required high WOB for conical cutters, the ridged diamond element drill bit technology is studied.
Feng Songlin, Fan Song, Bao Lijun, Hou Baodong   +3 more
doaj  

Elaboration de gradients de composition continue dans des taillants PDC

, 2006
International audienceCemented carbides are composites which possess an excellent compromise between hardness and toughness. For years, to improve one property without decreasing the other one, the concept of graduated structure was widely studied.
Colin, Christophe, Dourfaye, Alfazazi, Sellami, Hedi, Sorlier, Elodie   +3 more
core   +1 more source

Discretion, Due Process, and the Prison Discipline Committee [PDF]

, 1985
A revised version of this paper was published as: Schafer, N.E. (1986). "Discretion, Due Process and the Prison Discipline Committee." Criminal Justice Review 11(2): 37–46 (Fall 1986).
Schafer, N. E.
core