P.S. 콘크리트 보의 비선형 최적설계

정철원,최규문,손용우 圓光大學校 1994 論文集 Vol.28 No.2

비선형 최적설계법을 개발하였다. 이 방법의 목적은 PC구조물의 극한에서 나타나는 거동을 예측하는 것이다. 그에 따른 주요결과를 제시하였고 콘크리트와 강의 실제 거동의 실험 과정에서 겪는 난점을 거론하였다. 특히 PC강선에서 이용가능한 다양한 응력-변형 관계를 비교하고 실제 특성에서 나타난 차이점을 관찰하였다. 그 관계들에 관하여 추천된 식들의 해당계수를 제시하였다. 그 결과는 PC강선의 종류와 양, 비 프리스트레스 인장과 압축철근의 양, 극한 콘크리트압축변형 등과 같은 주요 변수들의 극한 거동에서 영향이 나타난다는 것이다. 그 영향과 결과를 유도한 규준을 비교하는 데에 중점을 두었다. 이 연구에서 얻은 결과들로써 만약 추천된 규준을 사용하는 경우에 그 규준이 불안정한 설계를 유도할 가능성이 있는 부분과 또 관찰된 경향에 알맞게 규준을 수정하기 위하여 필요한 점을 지적할 수 있게 되었다. An approximate nonlinear design procedure is development. It is the aim of the procedure to predict the behavior at ultimate of prestressed and partially prestressed concrete members. We showed the main results and discussed some difficulties which we come (on in) simulating the actual behavior of concrete and steel. Especially the various available stress-strain relationships for prestressing steels are compared and variability in their actual properties is observed. Corresponding coefficients of recommended equations are given. It is the result that the influence on ultimate behavior of major variables such as type and amount of prestressing steel, the amount of nonprestressed tensile, compressive reinforcement, and the ultimate concrete compressive strain exists. Then we put an empasis on comparing the influence with code derived results. By results of this study, we could point out that if used. where the recommended code may lead to an unsafe design and what modifications may be needed to make the code suitable to the observed trends.

鐵筋콘크리트 構造物의 最適設計

鄭哲源,朴熙淳,孫鎔雨,崔圭文 圓光大學校 1989 論文集 Vol.23 No.2

이 論文에서는 最適化問題를 해결한다 : 彈牲設計에 비해 最大效率로 주어진 形態의 構造를 設計하여 모든 可能한 荷重組合下에서 그 構造의 崩壞와 그것의 臨界斷面의 first yield에 대한 어떤 지정된 最小荷重係數를 측정한다. 目的函數를 線形化하고, 모든 limit equilibrium constraint를 算出해 내는 方法을 개발하여 線形計劃法과 콤퓨터技法의 도움으로 그 問題를 해결한다. 관계되는 원리와 대응되는 最適解는 鐵筋콘크리트 連續보와 뼈대 構造를 例로서 설명되어 있다. The following optimization problem is solved in the paper : design a structure of given geometry for maximum efficiency vs. elastic design, so that under any possible load combination certain specified minimum load factors be guaranteed against both the collapse of the structure and the first yield of its critical sections. By linearizing the objective function and developing a method to generate all limit equilibrium constraints the problem is solved with the help of linear programming and computer techniques. The principles involved and corresponding optimal solutions are illustrated by the examples of a reinforced concrete continuous beam and frame.

Study on the Establishment of Free Trade Zone Agricultural Tariffs in China, Japan and South Korea Based on the GTAP Model

Kou Zheng,Kou Lianxiang,Yang Honghong 한중경제문화학회 2019 한중경제문화연구 Vol.12 No.-

Tariff Policy and Environmental Qualities of Imported Goods

Kou, Horn-In,Hu, Jin-Li,Hwang, Hong 세종대학교 국제경제연구소 2001 Journal of Economic Integration Vol.16 No.3

Tariff is a trade measure with both of the trade and environmental effects. This article analyzes the interaction between the tariff rate and the short and long run environmental qualities of imperfectly substitutive imported goods. In the first part, we analyze the effect of changing the tariff rate on the environmental qualities of imported goods. That is, the import country government sets up the tariff rate before the foreign exporters choose their environmental qualities. If improving environmental qualities reduces the rate of decrease of consumers' marginal utilities, then a reduction in the tariff rate results in higher environ-mental qualities; moreover, the long run environ-mental qualities of imported goods will be higher. In the second part, we discuss the effect of environmental quality improvement on the optimal tariff. That is, the foreign exporters choose their environmental qualities before the home country government sets up the tariff rate. When the consumers are not environmentally conscious, whether the importance of environmental qualities is emphasized or not, it is optimal for the government to impose a lower (higher) tariff rate on the high low) environmental quality imported goods. If the environmental quality improvement cost is sufficiently higher than the marginal pollution abatement and/or marginal environmental damage, or if the import country government emphasizes environmental qualities, then the long run tariff rate on high environmental quality imported goods should be lower than that of the short run tariff.

Comparative transcriptome analysis of Sweetpotato (Ipomoea batatas L.) and discovery of genes involved in starch biosynthesis

Kou Meng,Su Zai-Xing,Zhang Yun-Gang,Li Qiang 한국식물생명공학회 2020 Plant biotechnology reports Vol.14 No.6

Sweetpotato, Ipomoea batatas L., Convolvulaceae, rich in starch, is a major staple economically important root crop world wide. Limited functional genomics resources and whole genome studies could be improved through the development of next-generation sequencing technologies. Illumina sequencing of three sweetpotato varieties, Xushu 18, Xu 781 and Xushu 25, including de novo transcriptome assembly, functional annotation, and diferential expression of potential starch biosyn thesis-related genes are described. A total of 2508, 1807 and 3169 Mb clean reads were generated for Xushu 18, Xu 781 and Xushu 25, and were assembled into 32,112, 35,788 and 36,955 unigenes with an average length of 787, 802 and 824 bp, respectively. BLAST against the NCBI non-redundant protein, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the Gene Ontology (GO) databases have classifed these unigenes into functional categories for understanding gene functions and regulation pathways. The proportion of up-regulated DEGs was lower than that of the down-regulated DEGs among three sweetpotato cultivars. The similar proportion of the up/down-regulated gene number was presented between Xushu 25 and one of its parents (Xushu18 and Xu 781). Moreover, 14 unigenes related to starch biosynthesis in Xushu 18 and Xu 781were searched out from the transcriptome sequencing data. Furthermore, gene expression of these genes in storage root during diferent developing stages was also investigated, 6 types of gene expression patterns were summarized. The novel sequence dataset developed in this study will be helpful for the further genetic characterization and studies of starch biosynthesis in sweetpotato.

Rapid Detection of Noroviruses in Fecal Samples and Shellfish by Nucleic Acid Sequence-based Amplification

Kou Xiaoxia,Wu Qingping,Zhang Jumei,Fan Hongying The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.4

The purpose of this study was to determine the efficacy of a nucleic acid sequence-based amplification (NASBA) method of detecting noroviruses in artificially and naturally contaminated shellfish. We used 58 fecal samples that tested positive for noroviruses with electron microscopy (EM) to develop an NASBA assay for these viruses. Oligonucleotide primers targeting the polymerase coding region were used to amplify the viral RNA in an isothermal process that resulted in the accumulation of RNA amplicons. These amplicons were detected by hybridization with digoxigenin-labeled oligonucleotide probes that were highly specific for genogroup I (GI) and genogroup II (GII) of noroviruses. The expected band of 327bp appeared in denaturing agarose gel without any nonspecific band. The specific signal for each amplicon was obtained through Northern blotting in many repeats. All fecal samples of which 46(79.3%) belonged to GII and 12(20.6%) belonged to GI were positive for noroviruses by EM and by NASBA. Target RNA concentrations as low as 5pg/ml were detected in fecal specimens using NASBA. When the assay was applied to artificially contaminated shellfish, the sensitivity to nucleic acid was 100pg/1.5g shellfish tissue. The potential use of this assay was also confirmed in naturally contaminated shellfish collected from different ponds in Guangzhou city of China, of which 24 (18.76%) out of 128 samples were positive for noroviruses; of these, 19 (79.6%) belonged to GII and 5 (20.4%) belonged to GI. The NASBA assay provided a more rapid and efficient way of detecting noroviruses in fecal samples and demonstrated its potential for detecting noroviruses in food and environmental samples with high specificity and sensitivity.

Community fitness circle in China

( Kou Lei ) 대한운동사협회 2017 대한운동사협회 운동사대회자료집 Vol.2017 No.-

Shear mechanism of steel fiber reinforced concrete deep coupling beams

Kou Li,Jun Zhao,Wenbo Ren 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.2

Deep coupling beams are more prone to suffer brittle shear failure. The addition of steel fibers to seismic members such as coupling beams can improve their shear performance and ductility. Based on the test results of steel fiber reinforced concrete(SFRC) coupling beams with span-to-depth ratio between 1.5 and 2.5 under lateral reverse cyclic load, the shear mechanism were analyzed by using strut-and-tie model theory, and the effects of the span-to-depth ratio, compressive strength and volume fraction of steel fiber on shear strengths were also discussed. A simplified calculation method to predict the shear capacity of SFRC deep coupling beams was proposed. The results show that the shear force is mainly transmitted by a strut-and-tie mechanism composed of three types of inclined concrete struts, vertical reinforcement ties and nodes. The influence of span-to-depth ratio on shear capacity is mainly due to the change of inclination angle of main inclined struts. The increasing of concrete compressive strength or volume fraction of steel fiber can improve the shear capacity of SFRC deep coupling beams mainly by enhancing the bearing capacity of compressive struts or tensile strength of the vertical tie. The proposed calculation method is verified using experimental data, and comparative results show that the prediction values agree well with the test ones.

Facile synthesis of nitrogen-doped carbon dots (N-CDs) and N-CDs/NiO composite as an efficient electrocatalyst for oxygen evolution reaction

Kou Xiaoli,Xin Xin,Zhang Yan,Meng Long-Yue 한국탄소학회 2021 Carbon Letters Vol.31 No.4

Nitrogen-doped carbon dots (N-CDs), derived from the biomass (anthocyanin), are the novel additive to the nanocarbon materials, which is expected to bring a wide spectrum of novel applications. Moreover, metallic oxides are emerging for their unique potential for electrocatalysis. Herein, we report the synthesis of N-CDs for the selective detection of Fe3+ with a limit of detection of 2.57 μM in the range of 5–60 μM using ethylenediamine and H2O2 by a hydrothermal method. The obtained N-CDs displayed a spherical morphology with a particle size range of 2–7 nm and emitted blue luminescence at 394 nm under excitation at 319 nm. Meanwhile, we have demonstrated the fabrication of cost-efcient electrocatalysts for oxygen evolution reaction (OER) in an alkaline medium, employing N-CDs. Owing to the successful incorporation of N-CDs into NiO nanospheres, the resulting N-CDs/NiO with large surface areas, fast charge transfer, and increased conductivity vastly improved the catalytic activity. Remarkably, the optimal of N-CDs/NiO composite requires the overpotential of only 380 mV at a current density of 10 mA cm−2 and a relatively low Tafel slope of 57.96 mV dec−1 compared with pure NiO. These results open up a facile route for the application of N-CDs and ofer prospects for CD-metal hybrids as high OER catalysts in electrochemical energy devices.

Finite Element Analysis of Stresses and Movements at the Interface of the Embankment of Taechong Dam

Kou,Seok-Ku,Lim,Heui-Dae 忠南大學校 産業技術硏究所 1987 산업기술연구논문집 Vol.2 No.1

대청댐은 콘크리트댐과 휠댐으로 결합된 복합형댐으로서 1980년에 완공되었으나 건설기간은 물론 완공 후 현재까지 댐의 거동에 대한 이론적 해석이 미흡한 실정이며 특히 결합부의 interface는 제체의 가장 취약한 지점으로서 댐의 안정에 많은 영향을 주고 있다. 그러므로 본 연구에서는 interface의 응력과 변형을 해석하고자 하였으며 해석적 방법으로 hyperbolic모델을 적용한 비선형증가 유한요소해석방법을 이용하였다. 유한요소해석에 의한 예측치와 댐 건설시 설치한 측정계기에 의한 실측치를 비교 분석한 결과 만족할 만한 결론을 얻을 수 있었으며 결합부의 응력과 변형은 interface의 기울기와 상대적으로 단단한 콘크리트에 의한 응력전이의 영향을 가장 많이 받고 있는 것으로 나타났다. Taechong dam is a composite dam at which a junction was formed partly by butting the core against the end face of the concrete gravity section and partly by the core overlapping the face of the concrete. The concrete interface was instrumented with earth pressure cells and piezometers. This study intended to analyze stresses and movements of the interface which has been subjected to the weight of the construction materials. The constitutive law used in this study is the hyperbolic model and a nonlinear incremental finite element analysis simulating its construction behavior was carried out. The results obtained from the finite element analysis are compared with the measured values. From the comparison, it was founded that the predicted stresses were greater than the measured values and that the movements of the interface was largely controlled by the steepness of a batter and the relatively stiff concrete section.