계란껍질 분말을 혼입한 시멘트 페이스트의 역학 특석 및 CO₂ 배출량 연구

진옥곤 ( Chen¸ Yukun ),이한승 ( Lee¸ Hanseung ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.2

This study investigated the use of different amounts of eggshell powder (ESP), namely 5%, 10%, and 15% by weight, as a substitute for Ordinary Portland Cement. The results show that its flowability and 28-day compressive strength. Meanwhile the carbon dioxide emission was though sustainable assessment analyzed It was concluded that ESP replacement level of around 5% provides the best performance to reduces environmental pollution.

Vitamin D Receptor BsmI Polymorphism and Colorectal Cancer Risk: an Updated Analysis

Yu, Kun,Yang, Jing,Jiang, Yan,Song, Run,Lu, Qing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

Background: Previous studies have investigated the association between the vitamin D receptor (VDR) BsmI polymorphism and colorectal cancer (CRC) susceptibility, but the results were conflicting. The aim of this study is to quantitatively summarize the relationship between this polymorphism and CRC risk. Materials and Methods: Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure (CNKI) and Chinese Biomedicine databases for studies published before November 2013. Summary odds ratios (ORs) and 95% confidence intervals (95%CIs) for VDR BsmI polymorphism and CRC were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate. Results: This meta-analysis included 14 case-control studies, which included 10,822 CRC cases and 11,779 controls. Overall, the variant genotype (BB) of the BsmI was associated with a lower CRC risk when compared with the wild-type bb homozygote (OR=0.66, 95%CI: 0.49-0.88). Similarly, a decreased CRC risk was also found in the dominant and recessive models. When stratifying for ethnicity, source of controls, and study sample size, associations were observed among Caucasians, population-based studies and studies with large study sample size (>1000 subjects). Limiting the analysis to the studies within Hardy-Weinberg equilibrium, the results were persistent and robust. No publication bias was found in the present study. Conclusions: This updated meta-analysis suggests that the VDR BsmI polymorphism may be associated with a moderate protective effect against CRC.

The Impression of the Imperial Palace

YuKun Li 한국콘텐츠학회 2013 ICCC International Digital Design Invitation Exhib Vol.2013 No.-

Virtual Flux and Positive-Sequence Power Based Control of Grid-Interfaced Converters Against Unbalanced and Distorted Grid Conditions

Yukun Tao,Wenhu Tang 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3

This paper proposes a virtual flux (VF) and positive-sequence power based control strategy to improve the performance of grid-interfaced three-phase voltage source converters against unbalanced and distorted grid conditions. By using a second-order generalized integrator (SOGI) based VF observer, the proposed strategy achieves an AC voltage sensorless and grid frequency adaptive control. Aiming to realize a balanced sinusoidal line current operation, the fundamental positive-sequence component based instantaneous power is utilized as the control variable. Moreover, the fundamental negative-sequence VF feedforward and the harmonic attenuation ability of a sequence component generator are employed to further enhance the unbalance regulation ability and the harmonic tolerance of line currents, respectively. Finally, the proposed scheme is completed by combining the foregoing two elements with a predictive direct power control (PDPC). In order to verify the feasibility and validity of the proposed SOGI-VFPDPC, the scenarios of unbalanced voltage dip, higher harmonic distortion and grid frequency deviation are investigated in simulation and experimental studies. The corresponding results demonstrate that the proposed strategy ensures a balanced sinusoidal line current operation with excellent steady-state and transient behaviors under general grid conditions.

Crystallization kinetics and magnetic properties of spinel transition metal ferrite nanoparticles

Yukun Sun,Dongyun Li,Pengzhao Gao,Zhouli Lu,Hongliang Ge 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.5

Spinel transition metal ferrite TMFe2O4 (TM = Co2+, Ni2+, Cu2+, and Zn2+) nanoparticles were prepared via a template-assistedsol-gel method followed by a calcining process, using metal nitrate precursors as raw materials. The prepared specimens werecharacterized using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). Their structures, magneticproperties, crystallization kinetics, and the influence of crystal size (D) on the magnetic properties were investigated. It wasfound that the crystal sizes of TMFe2O4 were positively proportional to the calcined temperature and time, and thecrystallization growth activation energy (Ea) increased with the increase of metal ionic radius. The optimum calcinationparameters were obtained to form a crystal closest to the standard crystal. Additionally, the saturation magnetization ofinverse spinel structure specimens was enhanced monotonously and their coercivity showed a potential decrease trend, whilethere was an opposite change trend for normal spinel structure specimens.

A three-axis robotic arm system for workpiece positioning and grasping based on monocular vision

Yukun Shi,Bingfeng Ju 한국생산제조학회 2018 한국생산제조시스템학회 학술발표대회 논문집 Vol.2018 No.10

Gender-Specific Differences in Gut Microbiota Composition Associated with Microbial Metabolites for Patients with Acne Vulgaris

( Yukun Huang ),( Lu Liu ),( Linna Chen ),( Lin Zhou ),( Xia Xiong ),( Yongqiong Deng ) 대한피부과학회 2021 Annals of Dermatology Vol.33 No.6

Background: The gut microbial dysbiosis and gender differences in the pathogenesis of acne vulgaris have long been postulated respectively. However, there was no data about a genderrelated discrepancy in gut microbiota and microbial metabolism in acne. Objective: This study aimed at identifying the underlying gender-related difference in gut microbiota and metabolism in acne vulgaris. Methods: Fecal samples were collected from 43 acne patients and 43 age and gender-matched controls. Gut microbiota was analyzed by sequencing the V3-V4 region of 16SrDNA gene and microbial metabolites were quantitatively detected using gas chromatography time-of-flight mass spectrometry. Results: Compared with healthy controls, the men had a lower abundance of 18 microbes such as Butyricicoccus , Clostridium sensu stricto, Faecalibaculum, Bacillus , Lactococcus , Blautia, Clostridiales, Lachnospiracea incertae sedis, Ruminococcus at genus level. However, the female patients only showed increased Clostridium sensu stricto and declined Oscillibacter and Odoribacterin. Additionally, the disordered metabolism of fatty acids was identified in male patients, while the dysbiosis of amino acids metabolism in female ones. Conclusion: The disorder of gut microbiota and metabolism in acne vulgaris was genderspecific, which supported the potential role of gender difference in the pathogenesis of this disease.

An Experimental and Numerical Study of Corona in a Cage with Sandy and Dusty Flow in High Altitude Area

Yukun Lv,Zekun Ge,Yunpeng Liu,Lei Zhu,Shaoke Wei 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

In order to study the effect of the high-altitude and dusty weather in northwest of China on the corona characteristics of transmission lines, a corona caged based experimental system with sandy and dusty flow condition is numerically investigated and designed. This system overcomes the difficulties caused by harsh environment and offers easy usage for off-site tests. The design parameters are mainly determined by the characteristics of strong sandstorm in northwest region and test requirements. By the comparison of numerical simulation of the particle diffusion in four programs with rectangular or circular air-duct, a practical technology, which introduces swirl to control the particle diffusion length, is obtained. Accordingly, the structure of round air-duct with swirl elbow in inlet and outlet of high level segment is selected as final program. Systems of control and measurement are designed at the same time. Field tuning results show that the test system could ensure the range of sandy and dusty coverage. The wind speed, sandy and dusty concentration could be controlled and meet the requirements of accuracy. The experimental system has many features, such as simple structure, easy to be assembled, disassembled, transported and operated, small space occupied.

Distributed Adaptive Neural Consensus Control for Stochastic Nonlinear Multiagent Systems with Whole State Delays and Multiple Constraints

Yukun Tao,Feifei Yang,Ping He,Congshan Li,Yuqi Ji 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.9

This paper presents a distributed adaptive neural tracking consensus control strategy for a class of stochastic nonlinear multiagent systems with whole state time delays, input and output constrains. The considered systems are involved in the existence of whole state delays and stochastic disturbances, which makes the controller design more difficult and complex. Firstly, time delays are related to unknown dynamic interactions with the whole states of the agent systems, and novel Lyapunov-Krasovskii functionals are constructed. Secondly, the smooth asymmetric saturation nonlinearity is given based on Gaussian error function, output constraints are achieved via barrier Lyapunov functions, and neural networks are utilized to deal with the completely unknown nonlinearities and stochastic disturbances. Then, based on Lyapunov stability theory, a delay-independent adaptive controller is developed via Lyapunov-Krasovskii functionals and backstepping technique, and it reduces the complexity of learning parameters. It is proved that the proposed approximation-based controller can guarantee that all closed-loop signals are cooperatively semi-globally uniformly ultimately bounded (CSGUUB), and the tracking errors between the followers and the leaders eventually converge to a small neighbourhood around the origin. Finally, simulation studies are carried out, and the simulation results verify the correctness and effectiveness of the proposed Strategy.

Thermal-Hydraulic-Mechanical Coupling Research on Overburden Pressure Mitigated Ice Lens Growth in the Freezing Soil

Yukun Ji,Guoqing Zhou,Matthew R. Hall,Veerle Vandeginste,Xiaodong Zhao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4

Frost heave induced ground surface uplift can have a destructive impact on infrastructures when freezing methods are used for underground construction. The complexity of overburden pressure and the coupled heat and mass transport interaction and their relation to different water flow rates make frost heave modelling an interesting but challenging task. A frost heave model describing phase transition and multiphase interactions (liquid-crystal-soil matrix) is presented in this paper and used to investigate the kinetic growth of the ice lens. By introducing water activity determined growth rate of ice crystals, the micro- and meso-physical mechanisms underlying ice lens growth involve ice crystal nucleation, crystallization, phase transition, and water migration in the frozen fringe are explored. This work indicates that the frozen fringe thickness, the ice crystals growth and the cryogenic-suction in the frozen fringe are particularly significant in determining the ice lens growth kinetics (frost heave) under different overburden pressures. The variation in ice lens growth under various overburden pressures appears to be controlled by the water flow path, cryogenic-suction, and permeability of the frozen fringe. This research reveals the kinetic growth of the ice lens, and helps to evaluate and mitigate geological hazards when artificial ground freezing is applied.