수축저감제와 혼화재를 병용한 콘크리트의 공학적 특성

金光華,김종,한민철,정평유,한천구 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)

The objective of this paper is to investigate the physical and mechanical properties of concrete incorporating shrinkage reducing admixture(SRA) and mineral admixture(MA) such as fly ash and blast furnace slag powder. According to results, for fresh concrete properties, increase of SRA content leaded to reduce the fluidity and air content sharply. For setting time, use of SRA caused concrete to accelerate setting time, and compared with plain concrete it retarded by incorporating MA. Compressive strength decreased with an increase in SRA content, and when incorporating MA, compared with plain concrete, it shows lower compressive strength in early age but similar or increase by the elapse of age due to the pozzolanic and latent hydration reaction. For drying shrinkage, concrete shows decline tendency with an increase in SRA content due to the relaxation effect at the capillary tension in concrete by SRA. In the scope of this paper, it is found that the use of SRA with 1.0% has optimum effects on the various properties of concrete, and the combinations of SRA and fly ash will ensure the stability for drying shrinkage.

수축저감제 혼입률 변화에 따른 콘크리트의 공학적 특성에 관한 연구

한민철,金光華,정규문,정평유,윤성노,한천구 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

In this paper, tests are carried out using concrete incorporating shrinkage reducing agent(SR) in order to investigate the engineering properties of concrete. The contents of SR and W/C are varied. According to test results, as for fresh concrete, as SR content increases, slump and air content shows decline tendency, and setting time is accelerated with increase of SR content and decrease of W/C. As for compressive strength, as SR contents increases compressive strength shows to be decreased. As for the effect of SR on drying shrinkage, it shows to be reduced with increase of SR content. This is due to the reduced surface tensile strength of water and tensile strength of capillary pore in concrete.

Isoindolin-1-ones from the stems of Nicotiana tabacum and their antiviral activities

Guang-Yu Yang,Jia-Meng Dai,Zhen-Jie Li,Jin Wang,Feng-Xian Yang,Xin Liu,Jing Li,Qian Gao,Xue-Mei Li,Yin-Ke Li,Wei-Guang Wang,Min Zhou,Qiu-Fen Hu 대한약학회 2022 Archives of Pharmacal Research Vol.45 No.8

In previous studies, several isoindolin-1-oneanalogs that exhibited signifi cant anti-tobacco mosaic virus(anti-TMV) activities were isolated from Nicotiana tabacum . Since gene-editing mutants provide a new sample for thediscovery of active metabolites, we focused on the stems ofYN-18–23 (a mutant N. tabacum for gene editing with thealkaloid metabolic pathway cultivated by Yunnan TobaccoCompany), which led to the isolation of four new ( 1–4 )and four known ( 5–8 ) isoindolin-1-ones. To the best of ourknowledge, nicindole C ( 3 ) is the fi rst subclass of isoindolin-1-one bearing a pentacyclic ketone, while nicindole D ( 4 )is the fi rst example of isoindolin-1-one bearing a methylpyridin-2-(1 H )-one moiety. Compounds 1–4 were testedfor their anti-TMV activities, and the results revealed thatcompounds 1 , 3 , and 4 exhibited high anti-TMV activities atconcentrations of 20 μM with inhibition rates of 48.6, 42.8,and 71.5%, respectively. These rates are higher than the inhibitionrate of the positive control (33.2%). The mechanisticstudy of compound 4 , which had the highest anti-TMV activityrevealed that increased potentiation of defense-related enzyme activities and downregulation of expression of theNtHsp70 protein may induce resistance in tobacco againstthe viral pathogen TMV. Molecular docking studies alsorevealed that the isoindolin-1-one substructure is fundamentalfor anti-TMV activity. The methyl-pyridin-2-(1 H )-onemoiety in compound 4 and the 2-oxopropyl groups in compounds1 and 3 at the N -2 position may increase inhibitoryactivities. This study of the structure–activity relationshipis helpful for fi nding new anti-TMV activity inhibitors. Tostudy whether the isoindolin-1-ones have broader antiviralactivities, compounds 1–4 were also tested for their antirotavirusactivities. Compound 4 exhibited high anti-rotavirusactivity with a therapeutic index (TI) value of 20.7. This TI value is close to that of the positive control (20.2).

Experimental Study of Composite Steel Plate Shear Wall with Flush End-Plate Connection

Jin-Guang Yu,Xiao-Tian Feng,Ji-Ping Hao,Xi Gao 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.1

This paper presents an investigation on the structural performance of steel plate shear wall (SPSW) with fl ush end-plate beam–column connections and infi ll precast reinforced concrete (precast RC) panels. Two single-span two-story SPSW specimens, including unstiff ened SPSW (NBRP) and precast RC panel restrained SPSW (Con-BRP), are fi rst tested, followed with a parametric study by fi nite element method. Precast RC cover panels are installed on both sides of the infi ll steel plate and are disconnected from steel frame. Test results indicate that the use of precast RC cover panels increases the load carrying and energy dissipation capacities of the SPSW structure, but decreases its ductility. It is also eff ective in reducing the inward fl exural deformation of columns. Moreover, the stiff ening eff ect of the infi ll steel plate on the beam–column connections remains, which is a result of the precast RC cover panel’s resistance to the local buckling and the tears of the infi ll steel plates. The infl uence of the gap size between the precast RC cover plate and frame members on the failure mode of the specimen Con-BRP is also investigated, based on which a maximum gap size is recommended. Conclusions are drawn that SPSW structure with fl ush end-plate beam–column connections and precast RC cover panels fully exploits the strength of infi ll steel plates and exhibits excellent structural performance.

Anatomical variations of the origin of the segment 4 hepatic artery and their clinical implications

Jin, Guang Yu,Yu, Hee Chul,Lim, Hyung-Sun,Moon, Jang Il,Lee, Jeong Hun,Chung, Jin Wook,Cho, Baik Hwan Wiley Subscription Services, Inc., A Wiley Company 2008 Liver transplantation Vol.14 No.8

<P>The threat of ischemic complications following massive resection, especially in living donor hepatectomy or split liver transplantation, has been haunting surgeons for many years. Postmortem dissections of 62 livers were performed to investigate anatomical variations of the principal artery for segment 4 (A4). The origin of A4 was examined separately in the liver with (n = 46) or without (n = 16) an aberrant left hepatic artery (abLHA). A4s were found to be extrahepatic or intrahepatic branches of the right hepatic artery (RHA), left hepatic artery, or proper hepatic artery and were categorized into 4 different types according to their origins. The RHA type, originating from the RHA or right anterior hepatic artery (RAHA), was the most common pattern in our series. The A4 roots had a strong tendency of stemming from the RHA (n = 12) even in the livers with abLHA (n = 16). Among the RHA-type A4s, the A4 arising from RAHA (n = 2) is supposed to be the most dangerous variant because it can cause an ischemic change in the remaining part of the liver after right hepatectomy. In conclusion, in the era of living donor liver transplantation, paying particular attention to the point of origin of A4 is a prerequisite, especially when the lateral section is relatively small. Arterial injuries to A4 during split liver transplantation may also increase the risk of hepatic artery thrombosis and ischemic cholangiopathy. Liver Transpl 14:1180–1184, 2008. © 2008 AASLD.</P>

Generation of Neuronal-Like Cells from Umbilical Cord Blood-Derived Mesenchymal Stem Cells of a RFP-Transgenic Cloned Cat

JIN, Guang-Zhen,YIN, Xi-Jun,YU, Xian-Feng,CHO, Su-Jin,CHOI, Eu-Gene,LEE, Young-S,JEON, Jin-Tae,YEE, Sung-Tae,KONG, Il-Keun Japanese Society of Veterinary Science 2008 The Journal of veterinary medical science Vol.70 No.7

<P>Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) are multipotent adult stem cells, which can differentiation into cells of connective tissue and neural lineages. This study investigated the potential for neuronal differentiation of red fluorescent protein (RFP)-transgenic cat UCB-derived MSCs. The cells were cultured in pre-induction medium for 24 hr and in neuronal-induction medium for 72 hr. Immunofluorescent staining showed that 6.85% of the total cells were β III-tubulin-positive, 3.37% were neurofilament light (NF-L)-positive and 7.04% were neurofilament medium (NF-M)-positive. A β III-tubulin band was detected by western blot analysis. Our results demonstrate that RFP-transgenic UCB-derived MSCs can be differentiated into neuronal cells <I>in vitro</I>. Thus, RFP-transgenic MSCs could provide alternative tracing material for stem cell transplantation.</P>

The Three-wavelength PR<SUP>3+</SUP>:YLF Laser at 604 nm 607 nm and 640 nm with Fabry-Perot Etalon

Long Jin,Yu-Shi Jin,Yuan Dong,Qing-Song Li,Yong-Ji Yu,Shu-Tao Li,Guang-Yong Jin 한국광학회 2018 Current Optics and Photonics Vol.2 No.5

A three-wavelength Pr<SUP>3+</SUP>:YLF laser at 604 nm, 607 nm and 640 nm simultaneously output by Fabry-Perot (F-P) etalon has been obtained. A 444 nm blue laser diode is used for pumping the Pr<SUP>3+</SUP>:YLF crystal, and a 0.1 mm F-P etalon is inserted in the resonator to select wavelength. The theoretical model of three-wavelength Pr<SUP>3+</SUP>:YLF laser is established, by adjusting the tilt angle of the etalon, the transmittances of the different wavelengths can be controlled, and the threshold values can be made to equalize by controlling the loss among different wavelengths. In the experiment, when the tilt angle of etalon is 9° and the optimized length of resonator is 48 mm, the total output power of 25 mW at the three-wavelength is achieved at incident pump power of 7.5 W.

Ginsenoside Rh2 reduces depression in offspring of mice with maternal toxoplasma infection during pregnancy by inhibiting microglial activation via the HMGB1/TLR4/NF-kB signaling pathway

Xiang Xu,Yu-Nan Lu,Jia-Hui Cheng,Hui-Wen Lan,Jing-Mei Lu,Guang-Nan Jin,Guang-Hua Xu,Cheng-Hua Jin,Juan Ma,Hu-Nan Piao,Xuejun Jin,Lian-Xun Piao 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.1

Background: Maternal Toxoplasma gondii (T. gondii) infection during pregnancy has been associated with various mental illnesses in the offspring. Ginsenoside Rh2 (GRh2) is a major bioactive compound obtained from ginseng that has an anti-T. gondii effect and attenuates microglial activation through toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-kB) signaling pathway. GRh2 also alleviated tumor-associated or lipopolysaccharide-induced depression. However, the effects and potential mechanisms of GRh2 on depression-like behavior in mouse offspring caused by maternal T. gondii infection during pregnancy have not been investigated. Methods: We examined GRh2 effects on the depression-like behavior in mouse offspring, caused by maternal T. gondii infection during pregnancy, by measuring depression-like behaviors and assaying parameters at the neuronal and molecular level. Results: We showed that GRh2 significantly improved behavioral measures: sucrose consumption, forced swim time and tail suspended immobility time of their offspring. These corresponded with increased tissue concentrations of 5-hydroxytryptamine and dopamine, and attenuated indoleamine 2,3-dioxygenase or enhanced tyrosine hydroxylase expression in the prefrontal cortex. GRh2 ameliorated neuronal damage in the prefrontal cortex. Molecular docking results revealed that GRh2 binds strongly to both TLR4 and high mobility group box 1 (HMGB1). Conclusion: This study demonstrated that GRh2 ameliorated the depression-like behavior in mouse offspring of maternal T. gondii infection during pregnancy by attenuating the excessive activation of microglia and neuroinflammation through the HMGB1/TLR4/NF-kB signaling pathway. It suggests that GRh2 could be considered a potential therapy in preventing and treating psychiatric disorders in the offspring mice of mothers with prenatal exposure to T. gondii infection.

Effect of Sub-Structure and Precipitation Behavior on Mechanical Properties of Al–xCu–Li Alloys

Yu‑zhuo Li,Guang‑jun Zeng,Ding‑ding Lu,Zhen‑zhen Liu,San‑xi Deng,Peng‑cheng Ma,Yong‑lai Chen,Rui‑feng Zhang,Jin‑feng Li 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

The tensile properties and microstructure of extruded and cold rolled 2A55 Al–Li alloys with different Cu content werestudied. After solution treatment, the strength of extruded sheets is slightly higher than that of cold rolled sheets due to strongdeformation texture and high density of substructure. However, the strength change order is different with the increase of Cucontent with T6-24 h. The extruded sample with higher Cu content have higher strength due to many dense T1precipitates. The δ′/θ′/δ′ composite precipitates and θ′ precipitates suppress the formation of T1precipitates, which cause cold rolled samplewith higher Cu content shows lower strength. Additionally, many fine T1precipitates nucleate at the sub-grain boundariesformed in the extrusion process, which have a significant effect on the mechanical property.

The Impact Force of Large Boulders with Irregular Shape in Flash Flood and Debris Flow

Guang-Wu Si,Xiao-Qing Chen,Jian-Gang Chen,Jin-Bo Tang,Wan-Yu Zhao,Ke Jin 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.10

The impact force of large boulders carried by flash floods and debris flows is one of the main causes of structural damage. The elastoplastic modification model of the impact force was derived, and it was found that the impact force was significantly affected by large boulders with irregular shapes. However, a large boulder with an irregular shape is often simplified as an isovolumetric sphere or ellipsoid, which may lead to inaccurate calculation of the impact force. In this paper, a method to obtain the irregular shape of a large boulder in the field is proposed by combining field investigation, image processing, and graphic analysis. The irregular shape is described by a nonuniform rational B-spline (NURBS) curve. The curvature radii corresponding to the potential impact contact points on the surface of a large boulder, which can reflect the influence of the irregular shape, are extracted according to the concavity and convexity analysis. The results demonstrate that NURBS curves can describe irregular shapes both conveniently and accurately. The impact force was corrected by the elastic–plastic model, the impact force increased with increasing curvature radius, and the increase ratio of the impact force gradually decreased with increasing velocity. Compared with the isovolumetric sphere model and ellipsoid model, the impact force calculated by the ellipsoid model is closer to the results obtained in this paper. The reduction factor of the impact force is 0.03 − 0.16, which first increases significantly and then linearly increases with increasing curvature radius. In addition, the reduction factor of the impact force initially exhibits a significant decline with increasing velocity and then gradually stabilises. To simplify parameter selection, we suggest using the maximum curvature radius in the ellipsoid model as the calculation parameter in calculating the impact force of large boulders.