Search

Your search keyword '"Wang, Yonglong"' showing total 224 results
Start Over Author "Wang, Yonglong"
224 results on '"Wang, Yonglong"'

1. Mechanism and application of drill pipe bending induced borehole collapse in soft coal seam drilling

Author

Wang Yonglong, Yu Zaijiang, Guo Jiakuan, Du Kang, Ma Denghui, and Zhao Aoqi

Subjects
borehole collapse, drill pipe stress, gas extraction, notched drill pipe in four wings, soft coal seam, Technology, Science
Abstract

Abstract Gas extraction drilling is a necessary measure for managing gas hazards. For soft coal seams where gas extraction drilling holes are prone to collapse, it is believed that drill rod disturbance is the main cause of hole collapse. This study proposes a research approach to reduce wall stress by optimizing the drill rod structure. Through theoretical analysis, numerical simulation, and industrial tests, a stress model for the drill rod inside the hole was established, and a wall stress equation was derived. The effects of various parameters on wall stress were analyzed. The study suggests optimizing the drill rod structure to reduce the disturbance‐induced wall stress. SolidWorks was used for drilling stress simulation, and a four‐winged concave groove drill rod was developed. After strength verification, comparative industrial tests were conducted. The research results show that as the line density increases, the wall stress of the drilling hole increases. As the length of the suspended section increases, the wall stress initially decreases and then increases. With increasing drilling thrust, wall stress increases linearly, and the growth rate is greater with a larger diameter difference between the drill hole and the drill rod. Numerical simulation results indicate that the critical point maximum stress at the hole entrance, the critical point maximum stress at the hole bottom, and the average stress at the bottom section of the four‐winged concave groove drill rod with a concavity of 5 are significantly reduced compared to those of circular and grooved drill rods. Industrial test results show that using the four‐winged concave groove drill rod significantly reduces the extent of hole collapse. This study provides a reference for addressing the issue of hole collapse in gas extraction drilling for soft coal seams.

Published
2024
Full Text
View/download PDF

2. Transverse spin-orbit interaction of light

Author

Fu, Tong, Lin, Jiaxin, Xu, Yuhao, Jia, Junji, Wang, Yonglong, Zhang, Shunping, and Xu, Hongxing

Subjects
Physics - Optics
Abstract

Light carries both longitudinal and transverse spin angular momentum. The spin can couple with its orbital counterpart via the Berry phase, known as the spin-orbit interaction (SOI) of light. The SOI of light discovered previously belongs to the longitudinal one, which relies on the Berry phase in momentum space, such as the optical Magnus effect and the spin Hall effect. Here, we show that transverse SOI, relying on the Berry phase in real space, is inherent in the Helmholtz equation when transverse spinning light propagates in curved paths. The transverse SOI lifts the degeneracy of dispersion relations of light for opposite transverse spin states, analogous to the Dresselhaus effect. Transverse SOI is ubiquitous in nanophotonic systems where transverse spin and optical path bending are inevitable. It can also explain anomalous effects like the dispersion relation of surface plasmon polariton on curved paths and the energy level of whispering gallery modes. Our results reveal the analogies of spin photonics and spintronics and offer a new degree of freedom for integrated photonics, spin photonics, and astrophysics.

Published
2023

23. Two dimensional MRT LB model for compressible and incompressible flows

Author

Chen, Feng, Xu, Aiguo, Zhang, Guangcai, and Wang, Yonglong

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Fluid Dynamics
Abstract

In the paper we extend the Multiple-Relaxation-Time (MRT) Lattice Boltzmann (LB) model proposed in [Europhys. Lett. \textbf{90}, 54003 (2010)] so that it is suitable also for incompressible flows. To decrease the artificial oscillations, the convection term is discretized by the flux limiter scheme with splitting technique. New model is validated by some well-known benchmark tests, including Riemann problem and Couette flow, and satisfying agreements are obtained between the simulation results and analytical ones. In order to show the merit of LB model over traditional methods, the non-equilibrium characteristics of system are solved. The simulation results are consistent with physical analysis.

Published
2013

31. Hexagonal Defect‐Rich MnOx/RuO2 with Abundant Heterointerface to Modulate Electronic Structure for Acidic Oxygen Evolution Reaction.

Author

Wu, Zexing, Wang, Yonglong, Liu, Dongzheng, Zhou, Bowen, Yang, Pengfei, Liu, Runze, Xiao, Weiping, Ma, Tianyi, Wang, Jinsong, and Wang, Lei

Subjects
*OXYGEN evolution reactions, *HYDROGEN as fuel, *DENSITY functional theory, *CLEAN energy, *CHARGE exchange
Abstract

Developing green hydrogen energy to power future societies has driven the progress of proton‐exchange membrane water electrolyzers (PEMWE). However, due to the complex anode oxygen evolution reaction (OER) electron transfer process and the strong acidic environment, the most effective catalysts are still Ir‐based nanomaterials. Therefore, exploiting low cost acidic OER catalysts to meet the needs of PEMWE remains a challenging and rewarding task. Herein, hexagonal‐shaped and defect‐rich MnOx/RuO2 heterojunction nanosheets (H/d‐MnOx/RuO2) is designed. The oxygen vacancies and heterogeneous structure enable the H/d‐MnOx/RuO2 catalyst to reach 10 mA cm−2 with only overpotential 178 mV in 0.5 m H2SO4. Density functional theory shows that the oxygen vacancies and heterogeneous interface facilitates the reduction of the adsorption energy of *OOH and the reduction of the energy level of Ru‐Oads, thus suppressing the involvement of lattice oxygen and enhancing the durability. This study provides an effective way to design efficient catalysts for hydrogen production in PEMWE. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

32. Active learning based on a hybrid neural network modeller

Author

Wang, Yonglong

Subjects
621.3, Bionics
Abstract

Various methods are investigated for selecting training data for the purpose of training neural networks. A new method called MIQR (Maximum Inter-Quartile Range) is proposed for effectively selecting a concise set of training data. In addition, the ensemble concept is introduced in this new method. Data selection is not unduly influenced by “outliers”, rather, it is principally dependent upon the “mainstream ” output of the ensemble networks. Encompassed in the new method is a very simple ancient Chinese philosophical idea, i.e. “the minority obeys the majority”. These techniques are nonparametric in the sense that several different neural networks comprise an ensemble or committee and co-operatively work together with each other to achieve a common goal. Because these are different neural networks (hybrid model), they can be complementary in the entire learning system, and therefore effectively enhance the entire learning system’s efficiency and accuracy. For learning, the neural networks attempt to actively select the most informative and important training data. The methods described in this thesis pleasingly satisfy this need, and compare favourably with contending methods. Many experiments have been done to corroborate theoretical and empirical conjectures. The results are quite pleasing in that this new method is not only as “active learning” much better than “passive learning” both in data selection and in generalisation performance, but also outperforms other existing contending active learning methods. In particular, the results are very satisfying and interesting when the method is applied to discontinuous functions. Although the experiments are conducted with clean data selection, it should be easy to extend them to noisy data selection since the method developed is validated using unlabelled data. The algorithm developed for these methods has been rigorously tested, and proves to be highly autonomous and robust. The methods developed here are not restricted to use on neural networks. More generally, they can be applied to other scientific research and economic fields, even educational and sociological behaviour.

Published
1998

Catalog

Books, media, physical & digital resources
See catalog results