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.

Reestimation of The Renminbi

Guang-Dong Yu,Seung-Hun Yu 한국무역연구원 2014 貿易 硏究 Vol.10 No.3

In this paper, we analyze mainly the well-known relationship between deviation from absolute purchasing power parity and real per capita income by using panel regression models, and verify Balassa-Samuelson effects. We determine how much of the degree of misalignment of the renminbi (RMB) stands relative to the equilibrium real exchange rate using these methods. Although undervaluation or overvaluation of the RMB exists, most of the misalignments from the equilibrium exchange rate keep within two standard error bands. The Balassa-Samuelson effects are at work. Even considering the serial correlation and control variables (demographic variables, current account, M2/GDP, capital openness, corruption index, an interaction term), similar results can be obtained.

The Research of 3 D Point Cloud Registration Method Based On Regular Hexahedron Color Targets

Yu Guang,Shi Yunbo,Yu Boyang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.4

Coded structured light measurement is the important method of modern non-contact optical measurement, restricted by the camera field of view, the surfaces to be measured can complete a single perspective measurement, this is the 3 d point cloud registration, point cloud registration can reflect three-dimensional topography on the surface of the object, and it has reached the requirement of comprehensiveness.This paper has built coded structured light 3 d measurement system, to explore 3 d point cloud registration method based on regular hexahedron color targets with high accuracy, fast registration, which can be applied to industrial components comprehensive measuring characteristics.

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>

Correlation between Non-Alcoholic Fatty Liver Disease and Visceral Adipose Tissue in Non-Obese Chinese Adults: A CT Evaluation

Ai-Hong Yu,Yang-Yang Duan-Mu,Yong Zhang,Ling Wang,Zhe Guo,Yong-Qiang Yu,Yu-Sheng Wang,Xiao-Guang Cheng 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.5

Objective: To investigate the correlation between non-alcoholic fatty liver disease and visceral adipose tissue in non-obese Chinese adults using computed tomography (CT). Materials and Methods: The study included 454 subjects undergoing abdominal CT scan. Degree of CT attenuation in liver and spleen, and the degree of fat infiltration in liver were evaluated according to three indices: the attenuation value of liver parenchyma (CTLP), the attenuation ratio of liver and spleen (LSratio) and the attenuation difference between liver and spleen (LSdif). Visceral fat area (VFA) and total fat area (TFA) at L2/3 and L4/5 levels were measured, and the abdominal subcutaneous fat area (SFA) was calculated. Bivariate correlation analysis was carried out to determine the correlation among these factors. Results: In men, VFA, SFA and TFA at L2/3 and L4/5 levels showed significant differences in terms of the three indices to distinguish fatty liver from non-fatty liver (all, p < 0.001). In men, all the three indices showed negative correlation with TFA, SFA and VFA (all, p < 0.001). The negative correlation between the three indices and VFA at the L2/3 level was higher than at L4/5 level (r = -0.476 vs. r = -0.340 for CTLP, r = -0.502 vs. r = -0.413 for LSratio, r = -0.543 vs. r = -0.422 for LSdif, p < 0.001, respectively). The negative correlation between LSratio, LSdif and VFA at L2/3 and L4/5 levels was higher than SFA at the corresponding level. In women, all the three indices showed negative correlation with VFA and TFA at L2/3 and L4/5 levels, and the negative correlation between CTLP and VFA was higher at L2/3 level than at L4/5 level (r = -0.294 vs. r = -0.254, p < 0.001). Conclusion: In non-obese Chinese adults, the degree of hepatic fatty infiltration showed a strong correlation with abdominal fat on CT. VFA at L2/3 level was more closely related to fatty liver compared with VFA at L4/5 level.

Calculative and experimental study of the CFRP tape spring

Yu-di Zuo,Guang Jin,Peng Xie 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8

A tape spring is a thin-walled, straight strip of material with curved cross-section, and the current trend is towards tape springs made of carbon fibre reinforced plastic (CFRP). In this paper, performance of the CFRP tape spring was studied and its bending moment’s calculative formula during opposite-sense bending process was derivated, also, the theoretical formula’s accuracy was assessed by means of detailed, non-linear finite-element analysis. Subsequently, a CFRP tape spring was practical designed and manufactured through twiningmoulding workmanship, and some experiments were conducted to study its bending characters, verifying the validity of the theoretical analysis and finite element simulation perfectly.

Identification of putative carboxylesterase and aldehyde oxidase genes from the antennae of the rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

Yu-Xing Zhang,Wen-Long Wang,Mao-Ye Li,Shi-Guang Li,Su Liu 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.3

In insects, odorant-degrading enzymes (ODEs) play essential roles in the degradation of volatile odorants and maintenance of olfactory sensitivity. ODEs include several enzyme families with detoxification functions, such as carboxylesterases (CXEs) and aldehyde oxidases (AOXs). The rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), is a serious rice insect pest in Asia. In this study, 18 putative CXE genes and four AOX genes were identified from the antennae of C. medinalis by retrieving a previously released transcriptome dataset. BLASTX searching and phylogenetic analyses showed that these genes are closely related to their respective orthologs in other lepidopteran species. Expression patterns of these genes were determined by reverse transcription- quantitative PCR (RT-qPCR). Four candidate genes, including three CmedCXEs (CmedCXE17, CmedCXE20 and CmedCXE24) and one CmedAOX (CmedAOX2) were antenna-enriched and considered potentially involved in odorant degradation. Our findings provide a comprehensive sequence resource and expression profiles of CXE and AOX genes in C. medinalis antennae, which may facilitate further studies of the odorant degradation mechanisms in this insect species.

Effect of the opening of a butterfly valve on the dynamic evolution of cavitation

Guang Zhang,Ze Yong Wu,Ke Xin Wu,Yu Qiong Ou,Heuy Dong Kim,Zhe Lin 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

As the key control equipment for the transmission of fluid medium, processing valves are widely used in the transmission systems of fluid medium in energy, chemical industry, metallurgy and other fields, which play important roles in the stability and reliability of the system operation. When the flow cross-section is operated in a sudden change, the pressure decreases rapidly at the downstream, which leads to the cavitation in the processing valves. Cavitation makes serious erosion and damage on the valve core and pipeline surface, which makes the leakage and noise problems in processing valves. This seriously affects the regulation performance and lifetime of processing valves. In this article, numerical simulations were carried out to investigate the transient cavitation in a model butterfly valve. By considering effects of local pressure on formation of cavitation, a modified model for calculating the diameter of cavitation bubbles was derived. Effects of valve opening degree were investigated on the dynamic evolution of cavitation by analyzing formation, development and collapse of cavitation. The generation, development and collapse of single cavitation bubble was obtained and discussed in details to state the interaction between vortices and cavitation. Attached and quasiperiodic cavitation were observed and analyzed at different valve opening degrees in detail as well.

Modeling of time-varying stress in concrete under axial loading and sulfate attack

Guang-Ji Yin,Xiao-Bao Zuo,Yu-Juan Tang,Olawale Ayinde,Dong-Nan Ding 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.2

This paper has numerically investigated the changes of loading-induced stress in concrete with the corrosion time in the sulfate-containing environment. Firstly, based on Fick’s law and reaction kinetics, a diffusion-reaction equation of sulfate ion in concrete is proposed, and it is numerically solved to obtain the spatial and temporal distribution of sulfate ion concentration in concrete by the finite difference method. Secondly, by fitting the existed experimental data of concrete in sodium sulfate solutions, the chemical damage of concrete associated with sulfate ion concentration and corrosion time is quantitatively presented. Thirdly, depending on the plastic-damage mechanics, while considering the influence of sulfate attack on concrete properties, a simplified chemo-mechanical damage model, with stress-based plasticity and strain-driven damage, for concrete under axial loading and sulfate attack is determined by introducing the chemical damage degree. Finally, an axially compressed concrete prism immersed into the sodium sulfate solution is regarded as an object to investigate the time-varying stress in concrete subjected to the couplings of axial loading and sulfate attack.