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Effects of Momentum Ratio and Weber Number on Spray Half Angles of Liquid Controlled Pintle Injector

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Journal of Thermal Science 2015年第1期24卷 37-43页

作者： Min Son Kijeong Yu Jaye Koo Oh chae kwon Jeong soo Kim Korea Aerospace University School of Aerospace and Mechanical Engineering Korea Aerospace University School of Mechanical Engineering Sungkyunkwan University Department of Mechanical Engineering Pukyong National University

A pintle injector is advantageous for throttling a liquid rocket engine and reducing engine weight. This study ex- plores the effects of momentum ratio and Weber number at various injection conditions on spray characteristics of the pintle injector for liquid-gas propellants. A liquid sheet is injected from a center pintle nozzle and it is broken by a gas jet from an annular gap. The pressure drops of propellants, and the pintle opening distance were consi- dered as control variables; using 0.1 -1.0 as a bar for the pressure drop of the liquid injection, a 0.01-4）.2 bar for the pressure drop of gas jet and a 0.2 - 1.0 mm for the pintle opening distance. The discharge coefficient was de- creased linearly before the pintle opening distance of 0.75 mm and then, the coefficient was slightly increased. Spray images were captured by a CMOS camera with high resolution. Then, the shadow and reflected images were analyzed. Spray distributions were measured by a pattemator with an axial distance of 50 mm from a pintle tip. Finally, the spray half angles had an exponentially decreasing correlation as a momentum ratio divided by the Weber number. Also, the spray half angles from the spray distribution were underestimated compared to those measured from the captured images.

关键词： Pintle Injector Spray Half Angle Spray Distribution Visualization

Design and optimization of a cavity-backed spiral antenna for use in 6-12 GHz band

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Journal of Central South University 2013年第7期20卷 1838-1843页

作者： Gyoo-soo chae Joong-soo Lim Division of Information & Communication Engineering Baekseok University

The design and optimization of a self-complementary two-arm Archimedean spiral antenna backed by an absorptive cavity were presented. Parametric studies on the proposed antenna structure were carried out by using CST MWS. Simulation results show that the proper choice of spiral turns and cavity depth can miniaturize the dimensions of the cavity-backed spiral antenna presented here. According to simulation results, prototype antennas operating in the 6 12 GHz band are fabricated and the dimension of the proposed cavity-backed spiral antenna is 22 mm (diameter)×15 mm (height). The performance of the proposed antenna was measured and compared with the simulation results. It is shown that the experimental results are consistent with the theoretical predictions and the suggested antenna is good enough to adapt for various wideband applications.

关键词： cavity-backed spiral antenna miniaturization balanced structure wideband balun

Biological therapy for ulcerative colitis:An update

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World Journal of Gastroenterology 2014年第37期20卷 13234-13238页

作者： Geom Seog Seo soo-Cheon chae Department of Gastroenterology Wonkwang University School of MedicineDigestive Disease Research Institute Department of Pathology Wonkwang University School of MedicineDigestive Disease Research Insti-tute

Of the diverse biological agents used for patients with ulcerative colitis, the anti-tumor necrosis factor-α agents infliximab and adalimumab have been used in large-scale clinical trials and are currently widely used in the treatment of inflammatory bowel disease patients. Recent studies have indicated that golimumab, oral tofacitinib and vedolizumab reportedly achieved good clinical response and remission rates in ulcerative colitis patients. Thus, we believe that the detailed investigation of various studies on clinical trials may provide important information for the selection of appropriate biological agents, and therefore, we have extensively reviewed such trials in the present study.

关键词： Ulcerative colitis Immune dysfunction Biological therapy Remission Clinical trial Inflammatory bowel disease

Interaction of Streamwise and Wall-Normal Velocities in Combined Wave-Current Motion

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China Ocean Engineering 2005年第4期19卷 557-570页

作者： In-soo KIM Daniel S.KOH Young-chae SONG Division of Construction and Environmental Engineering College of EngineeringKorea Maritime University Busan606791Korea

The aim of this paper is to present an analytical expression for the streamwise velocity distribution in a non-uniform flow in the presence of waves; the correlation between the horizontal and vertical velocity components has been compreheusively examined. Different from previous researches which attributed the deviation of velocity from the classical log-law to the wave Reynolds stress, i.e. - ρ uv^- only, this study demonstrates that the momentum flux caused by mean velocities, i.e., u^- and v^-, is also responsible for the velocity deviation, and it is found that the streamwise velocity for a flow in the presence of non-zero wall-normal velocity does not follow the classical log-law, but the modified log-law proposed in this study based on simplified mixing-length theorem. The validity of the modified log-law has been verified by use of available experimental data from published sources for combined wave-current flows, and good agreement between the predicted and observed velocity profiles has been achieved.

关键词： streamwise velocity distribution wave-current flow Reynolds shear stress non-zero wall-normal velocity

SEDIMENT TRANSPORT CAPACITY-AN IMPROVED BAGNOLD FORMULA

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International Journal of Sediment Research 2007年第1期22卷 27-38页

作者： Sung-Cheol KOH In-soo KIM Young-chae SONG

This paper re-examines Bagnold’s theorem of sediment transport. Different from the stream power defined by Bagnold, i.e., τoV, this study shows that the total load of sediment-laden flow, gt, is related to near bed energy dissipation rate, i.e., τou*’. An attempt is made to explain the empirical relation. The ratio (=k) of measured total load, gt, to the product of near bed velocity, u*’, and energy dissipation rate, τou*’, is analyzed. It is found that k is independent of the Rouse number, Z, if Z is greater than 2.6, but the coefficient k decreases with the increase of Z when Z < 2.6. An empirical relation between k and Z is developed. A systematic and thorough analysis of 1,458 sets of data collected from 16 rivers and canals confirms that the proposed formula can be used to compute the total load with accuracy.

关键词： Sediment transport River flow Total sediment discharge Stream power

Energy-Efficient Clustering Using Optimization with Locust Game Theory

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Intelligent Automation & Soft Computing 2023年第6期36卷 2591-2605页

作者： P.Kavitha Rani Hee-kwon chae Yunyoung Nam Mohamed Abouhawwash Department of Computer Science and Engineering Sri Krishna College of Engineering and TechnologyCoimbatore641008India Department of ICT Convergence Soonchunhyang UniversityAsan31538Korea Department of Mathematics Faculty of ScienceMansoura UniversityMansoura35516Egypt Department of Computational Mathematics Scienceand Engineering(CMSE)Michigan State UniversityEast LansingMI48824USA

Wireless sensor networks(WSNs)are made up of several sensors located in a specific area and powered by a finite amount of energy to gather environmental *** use sensor nodes(SNs)to collect and transmit ***,the power supplied by the sensor network is ***,SNs must store energy as often as to extend the lifespan of the *** the proposed study,effective clustering and longer network lifetimes are achieved using mul-ti-swarm optimization(MSO)and game theory based on locust search(LS-II).In this research,MSO is used to improve the optimum routing,while the LS-II approach is employed to specify the number of cluster heads(CHs)and select the best *** the CHs are identified,the other sensor components are allo-cated to the closest CHs to them.A game theory-based energy-efficient clustering approach is applied to *** each SN is considered a player in the *** SN can implement beneficial methods for itself depending on the length of the idle listening time in the active phase and then determine to choose whether or not to *** proposed multi-swarm with energy-efficient game theory on locust search(MSGE-LS)efficiently selects CHs,minimizes energy consumption,and improves the lifetime of *** findings of this study indicate that the proposed MSGE-LS is an effective method because its result proves that it increases the number of clusters,average energy consumption,lifespan extension,reduction in average packet loss,and end-to-end delay.

关键词： Wireless sensor network clustering routing cluster head energy consumption network’s lifetime multi swarm optimization game theory

Effects of core/shell volumetric ratio on the dielectric-temperature behavior of BaTiO_(3)

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Journal of Advanced Ceramics 2014年第1期3卷 76-82页

作者： Sang-chae JEON Byung-kwon YOON Kwan-Hyeong KIM Suk-Joong L.KANG Materials Interface Laboratory Department of Materials Science and EngineeringKorea Advanced Institute of Science and Technology291 Daehak-roYuseong-gu Daejeon 305-701Korea LCR Division Samsung Electro-MechanicsSuwon 443-743Korea

Two sets of(Mg,Y)-doped BaTiO_(3)samples were prepared to investigate the effects of the core/shell volumetric ratio on the dielectric-temperature behavior of BaTiO3:one set with samples of the same grain size but different core sizes and the other with samples of the same core size but different shell *** microstructural variation of the samples was characterized and their dielectric properties were *** both sets of samples,the temperature stability of the dielectric properties was generally improved with a reduction of the volumetric shell ratio regardless of the grain and core *** existed,however,a limit of the reduction;for the studied range,shell thickness of one third of the core radius appeared to be an optimum thickness for the given amounts of *** was concluded that the volumetric shell ratio should be optimized so as not to exceed a specific limit,for our case two thirds of the grain volume,to secure temperature stability of the dielectric properties of BaTiO_(3).

关键词： barium titanate core/shell structure dielectric properties temperature stability

Effects of acupuncture stimulation on brain activation induced by cue-elicited alcohol craving

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Neural Regeneration Research 2022年第5期17卷 1059-1064页

作者： Hyeok Gyu kwon Seong Hun Choi Joon Ho Seo chae Ha Yang Mi Young Lee Department of Physical Therapy College of Health ScienceEulji UniversityGyeonggiRepublic of Korea Department of Anatomy and Histology College of Oriental MedicineDaegu Haany UniversityGyeongsanRepublic of Korea Department of Rehabilitation Gyeongbuk Regional Rehabilitation HospitalGyeongsanRepublic of Korea Department of Physiology College of Korean MedicineDaegu Haany UniversityDaeguRepublic of Korea Department of Physical Therapy College of Biomedical ScienceDaegu Haany UniversityGyeongsanRepublic of Korea

Acupuncture has been shown to be effective on alcohol use ***,the underlying mechanism remains poorly *** investigate the effects of Shenmen(HT7)acupoint on brain activation induced by cue-elicited alcohol craving,30 right-handed healthy light to moderate alcohol drinkers were recruited from the *** were randomly assigned to undergo acupuncture either at HT7(experimental acupoint,n=15)or Jingqu(LU8,control acupoint,n=15)*** randomized controlled study was performed in Daegu Haany University and Daegu-Gyeongbuk Medical Innovation Foundation,Republic of *** and data collection were conducted from December 2018 to May *** results showed that after acupuncture at HT7 acupoint,the activation of orbitofrontal cortex and dorsolateral prefrontal cortex was greatly increased,while the activation of dorsolateral prefrontal cortex was obviously reduced,and subject's craving for alcohol was reduced when he/she seeing alcohol-related video clips involving various alcohols(beer,wine,or soju)or drinking *** at HT7 more greatly reduced subject's alcohol cravings than acupuncture at LU8 *** findings suggest that acupuncture can improve the self-control of mild to moderate social drinkers through the activation of the orbitofrontal cortex and dorsolateral prefrontal cortex,thereby reducing the craving for *** study protocol was approved by the Institutional Review Board of Daegu Haany University Korean Medicine Hospital,Republic of Korea(approval ***-D-18026-PRO-02)on November 30,2018.

关键词： acupuncture addiction alcohol brain activation craving cue functional MRI Shenmen(HT7)acupoint

Reduced micro RNA 375 in colorectal cancer upregulates metadherin-mediated signaling

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World Journal of Gastroenterology 2019年第44期25卷 6495-6507页

作者： Seol-Hee Han Ji-Su Mo Won-Cheol Park soo-Cheon chae Department of Pathology School of MedicineWonkwang UniversityIksanChonbuk 54538South Korea Digestive Disease Research Institute Wonkwang UniversityIksanChonbuk 54538South Korea

BACKGROUND The human microRNA 375(MIR375)is significantly downregulated in human colorectal cancer(CRC)and we have previously shown that MIR375 is a CRCassociated *** metadherin(MTDH)is a candidate target gene of *** To investigate the interaction and function between MIR375 and MTDH in human *** A luciferase reporter system was used to confirm the effect of MIR375 on MTDH *** expression levels of MIR375 and the target genes were evaluated by quantitative RT-PCR(qRT-PCR),western blotting,or *** MTDH expression was found to be upregulated in human CRC tissues compared to that in healthy *** show that MIR375 regulates the expression of many genes involved in the MTDH-mediated signal transduction pathways[BRAF-MAPK and phosphatidylinositol-4,5-biphosphate-3-kinase catalytic subunit alpha(PIK3CA)-AKT]in CRC *** MTDH expression levels were found to inhibit NF-κB inhibitor alpha,which further upregulated NFKB1 and RELA expression in CRC *** Our findings suggest that suppressing MIR375 expression in CRC regulates cell proliferation and angiogenesis by increasing MTDH ***,MIR375 may be of therapeutic value in treating human CRC.

关键词： MicroRNA 375 Metadherin Mitogen-activated protein kinase Angiogenesis Cell proliferation Colorectal cancer