The multidirectional vibration and coupling dynamics of drill string and its influence on the wellbore trajectory

Lin Yang,Jia-lin Tian,Qingyou Liu,Liming Dai,Zhichao Hu,Jurui Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

For improving the accuracy of wellbore trajectory prediction in complex wellbore structures, especially in the kick-off section, a longitudinal, torsional and radial coupled drill string dynamics model is proposed. At the same time, the coupling dynamics model is solved based on the energy method, and the torque, weight on bit (WOB), the longitudinal displacement and velocity, the torsional angular displacement and angular velocity of the drill bit are obtained during the normal drilling and the stick-slip vibration phase. Combining the numerical example and experimental test, the differences between different models and actual drilling trajectories are compared and analyzed. The research results indicate that the torsional vibration and the longitudinal vibration have a great influence on each other in the coupling model, and the longitudinal vibration displacement increases, which can effectively reduce the torque variation range of the torsional vibration. The operation of the bit stagnation is weakened, maintaining a relatively stable rotational angular velocity of rotation. The calculation results of the wellbore trajectory are more consistent with the experimental results, and can accurately reflect the real situation of the drilling process. The theoretical model has an important reference for predicting the new well structure, especially the judgment of wellbore trajectory of complex wellbore structures such as extended reach wells, horizontal wells, deep wells and high deep wells of coalbed methane, and the prediction of downhole dynamics results.

Study on the Improvement of Paying Taxes in China proposed by the Analysis of Paying Taxes in Korea and Japan

Dai-Jia LIN,Hyung-Ho KIM 동아시아경상학회 2021 The East Asian Journal of Business Economics Vol.9 No.3

Purpose - The purpose of this study is to analyze the root causes of changes in the rankings of paying taxes in Japan and Korea from 2019 to 2020, and put forward relevant policy recommendations for China from the perspective of enterprise tax burden and tax compliance costs. Research design, data, and methodology - This paper analyzes the data information of four indicators of Japan and Korea in paying taxes from 2009 to 2019, excel tool was used to summarize the essential reasons for the changes. Result - The results showed that, through the reform of tax system, especially the application of electronic tax system for tax declaration, and this is the fundamental reason why Korea has surpassed Japan in the ranking of Paying Taxes in recent five years. Conclusion - Drawing lessons from the reforms in South Korea and Japan, it is concluded that China should improve its tax ranking through two ways. First, deepen the reform of the main tax and fee system and reduce the burden of enterprise taxes and fees. Second, further simplify the tax procedures. Return rights and responsibilities to the enterprise.

Comparing eight types of ginsenosides in ginseng of different plant ages and regions using RRLC-Q-TOF MS/MS

Dai, Yu-Lin,Qiao, Meng-Dan,Yu, Peng,Zheng, Fei,Yue, Hao,Liu, Shu-Ying The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.2

Background: This article aims to compare and analyze the contents of ginsenosides in ginseng of different plant ages from different localities in China. Methods: In this study, 77 fresh ginseng samples aged 2-4 years were collected from 13 different cultivation regions in China. The content of eight ginsenosides (Rg₃, Rc, Rg₁, Rf, Rb₂, Rb₁, Re, and Rd) was determined using rapid resolution liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry (RRLC-Q-TOF MS/MS) to comparatively evaluate the influences of cultivation region and age. Results: Ginsenoside contents differed significantly depending on age and cultivation region. The contents of ginsenosides Re, Rc, Rg₁, Rg₃, and Rf increased with cultivation age, whereas that of ginsenoside Rb₁ peaked in the third year of cultivation. Moreover, the highest ginsenoside content was obtained from Changbai (19.36 mg/g) whereas the lowest content was obtained from Jidong (12.05 mg/g). Ginseng from Jilin Province contained greater total ginsenosides and was richer in ginsenoside Re than ginseng of the same age group in Heilongjiang and Liaoning provinces, where Rb₁ and Rg₁ contents were relatively high. Conclusion: In this study, RRLC-Q-TOF MS/MS was used to analyze ginsenoside contents in 77 ginseng samples aged 2-4 years from different cultivation regions. These patterns of variation in ginsenoside content, which depend on harvesting location and age, could be useful for interested parties to choose ginseng products according to their needs.

Fragmentation to a jet in the large z limit

Dai, Lin,Kim, Chul,Leibovich, Adam K. American Physical Society 2017 Physical Review D Vol.95 No.7

<P>We consider the fragmentation of a parton into a jet with small radius R in the large z limit, where z is the ratio of the jet energy to the mother parton energy. In this region of phase space, large logarithms of both R and 1 - z can appear, requiring resummation in order to have a well-defined perturbative expansion. Using the soft-collinear effective theory, we study the fragmentation function to a jet in this end-point region. We derive a factorization theorem for this object, separating collinear and collinear-soft modes. This allows for the resummation using renormalization group evolution of the logarithms ln R and ln(1-z) simultaneously. We show results valid to next-to-leading logarithmic order for the global Sudakov logarithms. We also discuss the possibility of nonglobal logarithms that should appear at two loops and give an estimate of their size.</P>

Fragmentation of a jet with small radius

Dai, Lin,Kim, Chul,Leibovich, Adam K. American Physical Society 2016 Physical Review D Vol.94 No.11

<P>In this paper, we consider the fragmentation of a parton into a jet with small jet radius R. Perturbatively, logarithms of R can appear, which for narrow jets can lead to large corrections. Using soft-collinear effective theory, we introduce the fragmentation function to a jet (FFJ), which describes the fragmentation of a parton into a jet. We discuss how these objects are related to the standard jet functions. Calculating the FFJ to next-to-leading order, we show that these objects satisfy the standard Dokshitzer-Gribov-LipatovAltarelli- Parisi evolution equations, with a natural scale that depends upon R. By using the standard renormalization group evolution, we can therefore resum logarithms of R. We further use the soft-collinear effective theory to prove a factorization theorem where the FFJs naturally appear, for the fragmentation of a hadron within a jet with small R. Finally, we also show how this formalism can be used to resum the ratio of jet radii for a subjet to be emitted from within a fat jet.</P>

Heavy quark jet fragmentation

Dai, Lin,Kim, Chul,Leibovich, Adam K. Institute of Physics Pub 2018 The journal of high energy physics Vol.2018 No.9

Humidity and Temperature Response Characteristics of Optical Fiber Dislocation Fusion Sensor Coated with Graphene Quantum Dots

Dai Lin Li,Xiao Dan Yu,Ning Wang,Wenting Liu,Shiqi Liu,Liang Xu,Dong Fang,Huapeng Yu 한국광학회 2023 Current Optics and Photonics Vol.7 No.5

An optical fiber dislocation fusion humidity sensor coated with graphene quantum dots is investigated. A Mach-Zehnder interferometer is fabricated with three dislocated single-mode fibers with graphene quantum dots coating humidity-sensitive materials. Humidity response experiments showed a good linear response and high sensitivity with easy fabrication and low-cost materials. From 22% to 98% RH, the humidity response sensitivity of the sensor is 0.24 dB/% RH, with 0.9825 linearity. To investigate the cross-response of humidity and temperature, temperature response experiments are conducted. From30 ℃ to 70 ℃, the results showed 0.02 dB/℃ sensitivity and 0.9824 linearity. The humidity responseexperimental curve is compared with the temperature experimental curve. The big difference between humidity sensitivity and temperature sensitivity is very helpful to solve the cross-response of humidity and temperature. The influence of temperature fluctuations in humidity measurements is not obvious.

Characterization and screening of anti-tumor activity of fucoidan from acid-processed hijiki (<i>Hizikia fusiforme</i>)

Dai, Yu-Lin,Jiang, Yun-Fei,Lee, Hyo Geun,Jeon, You-Jin,Kang, Min-Cheol Elsevier 2019 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.139 No.-

<P><B>Abstract</B></P> <P>The aim of this study was to investigate the antiproliferative effects of fucoidan from three regional hijiki (<I>Hizikia fusiforme</I>) samples (Zhejiang-China, Jeju-Korea [JH], and Wando-Korea) in East Asia. Hijiki was processed using 1% citric acid to decrease heavy metal content. The JH sample was separated using diethylaminoethyl-cellulose-ion exchange chromatography to obtain four active fractions (JHCF1-JHCF4) and their monosaccharide composition was detected using high-performance liquid chromatography. The structure of the crude polysaccharides and four fucoidan fractions was analyzed using Fourier-transform infrared spectroscopy. JHCF4 showed the highest fucose and sulfate content and decreased Hep3B cell growth in 48 h with a half-maximal inhibitory concentration of 33.53 ± 2.50 μg/ml, which represented the strongest anticancer activity. Further, nuclear staining with Hoechst 33342 and acridine orange-ethidium bromide staining demonstrated that the anticancer activity of JHCF4 was mediated by apoptosis. Moreover, JHCF4 down-regulated B-cell lymphoma extra-large, while up-regulating Bcl-2-associated X protein, caspase-3, and apoptotic bodies to different degrees in Hep3B cells. JHCF4 induced apoptosis via the generation of reactive oxygen species along with the concurrent loss of mitochondrial membrane potential, indicating the potential role of the mitochondria-mediated pathway. Therefore, these results indicate that JHCF4 exhibited antiproliferative effects on the investigated cancer cell lines.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three regional <I>Hizikia fusiforme</I> samples were processed using 1% citric acid to decrease the heavy metal content. </LI> <LI> Fraction 4 showed the highest fucose and sulfate content and represented the strongest anticancer activity. </LI> <LI> Evidence that fraction 4 induced apoptosis via the mitochondria-mediated pathway was found in Hep3B cells. </LI> </UL> </P>

Protective effects of extracts from six local strains of Pyropia yezoensis against oxidative damage in vitro and in zebrafish model

Dai, Yu-Lin,Kim, Gwang Hoon,Kang, Min-Cheol,Jeon, You-Jin The Korean Society of Phycology 2020 ALGAE Vol.35 No.2

Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC₅₀ scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo.

The Synthesis of Cellulose-graft-poly (L-lactide) by Ring-opening Polymerization and the Study of Its Degradability

Lin Dai,Shu Xiao,Yue Shen,Baichuan Qinshu,Jing He 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

Cellulose-graft-poly (L-lactide) (cellulose-g-PLLA) was successfully prepared via ring-opening polymerization (ROP) by using 4-dimethylaminopyridine (DMAP) as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The structure and morphology of the polymer was characterized by nuclear magnetic resonance (NMR) and transmission electron microscope (TEM). From wide-angle X-ray powder diffraction (WAXD) and degradation test (by acid, alkaline, PBS and enzyme solution), changes in the crystalline structure as a result of degradation was also investigated. The results indicated that materials which have low degree of crystallinity showing higher degradability, however, in acid liquor, enzyme solution, alkaline liquor and PBS system, the degradation rate of the polymer decreased by the above sequence. Moreover, with the further increase of graft degree of this material, its degradation degree decreased.