• Title/Summary/Keyword: Natural period formula

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A new equation based on PGA to provide sufficient separation distance between two irregular buildings in plan

  • Loghmani, Adel;Mortezaei, Alireza;Hemmati, Ali
    • Earthquakes and Structures
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    • v.18 no.5
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    • pp.543-553
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    • 2020
  • Past earthquakes experience shows that serious damage or collapse of buildings have dramatically accrued when sufficient separation distance has not been provided between two adjacent structures. The majority of past studies related to the pounding topic indicate that obtaining the gap size between two buildings is able to prevent collision and impact hazards during seismic excitations. Considering minimization of building collisions, some relationships have been suggested to determine the separation distance between adjacent buildings. Commonly, peak lateral displacement, fundamental period and natural damping as well as structural height of two adjacent buildings are numerically considered to determine the critical distance. Hence, the aim of present study is to focus on all mentioned parameters and also utilizing the main characteristic of earthquake record i.e. PGA to examine the lateral displacement of irregular structures close to each other and also estimate the sufficient separation distance between them. Increasing and decreasing the separation distance is inherently caused economical problems due to the land ownership from a legal perspective and pounding hazard as well. Therefore, a new equation is proposed to determine the optimum critical distance. The accuracy of the proposed formula is validated by different models and various earthquake records.

Anti-wrinkle Effect of Cosmetics Containing Duchesnea indica Extract (사매추출물을 함유하는 화장품의 주름 개선 효과)

  • Yang, Woong-Suk;Kim, Young-Min;Kim, Ee-Hwa;Seu, Young-Bae;Yang, Yoon-Jung;Kim, Hyun-Woo;Kang, Se Chan
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.36 no.4
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    • pp.281-288
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    • 2010
  • In this study, we investigated anti-oxidative effects of Duchesnea indica extracts by using Oxygen Radical Absorbance Capacity (ORAC). The extracts were prepared with 0 %, 30 %, 50 %, 70 % and 100 % aqueous ethanol respectively. The 30 % EtOH D. indica extract showed higher ORAC activity than the other extracts. Therefore, we performed in vitro studies on cytotoxicity of NIH-3T3 cells and MMP-8 collagenase inhibition using by the 30 % EtOH extract. The 30 % EtOH extract showed no cytotoxicity and significant inhibition on MMP-8 collagenase. And we performed clinical studies for the anti-wrinkle effect of the Di-Wrinkle Free Cream. The cream formula was prepared with 2 % arbutin and 1 % D. indica extract. Twenty one healthy women volunteers, ages of 35 and 50, applied the cream on their faces twice a day for 8 weeks. The skin was evaluated with PRIMOS (phaseshift rapid in vivo measuring of human skin) system and analyzed by the student's paired t-test. The wrinkles on the eye region were reduced by 13 % based on the PRIMOS system after 8 weeks. In the safety study of the Di-Wrinkle Free Cream, no symptoms were observed such as erythema, edema, scaling, itching, stinging, burning, tightness and prickling by visual observation and medical examination of volunteers for 8 weeks. Moreover, there was no noticeable skin disorder during experience period. These results suggested that D. indica extracts could be applied as cosmeceuticals effective for anti-wrinkle.

An analysis on geomorphic and hydraulic characteristics of dominant discharge in nam river (남강의 지배유량에 대한 하도지형 및 수리 특성 분석)

  • Kim, Ki Heung;Lee, Hyeong-Rae;Jung, Hea Reyn
    • Journal of Korea Water Resources Association
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    • v.49 no.2
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    • pp.83-94
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    • 2016
  • Geomorphological, bed material and hydraulic characteristics are basis informations for the planning, design and management of the river in the aspect of flood control and environmental conservation, and it is very important to use these informations for the design of stable channel. In this study, dominant discharge was selected, geomorphological and hydraulic characteristics were analyzed using that discharge and also the characteristics of bed materials distribution were analyzed and bed materials-flow resistance relationship was evaluated, for the upstream section of Namgang dam. The dominant discharge was estimated a return period of approximately 1.5 year and stream type were classified Segment 1 and Segment 2 in this stream. Also, the frequency of riffle-pool showed 4.4 because this study area has the characteristics of natural channel that have not channel-crossing structures. In dominant discharge, according to the results that analyzed relationship between $h/d_{50}$ and $V/u_*$ to calculate flow resistance by bed materials, Julian's formula showed to appropriate in channel where is relatively close to natural river and is predominantly consisted of gravel, cobble, boulder and rock in mountain, and it was confirmed that the image processing methodology will be easily applied to the analysis of bed materials distribution in future.

Effect of Lugol's Iodine Preservation on Cyanobacterial Biovolume and Estimate of Live Cell Biovolume Using Shrinkage Ratio (Lugol's Iodine Solution 첨가 후 보존 기간별 남조류 세포부피 변화 및 수축비를 이용한 생세포 부피 산정)

  • Park, Hae-Kyung;Lee, Hyeon-Je;Lee, Hae-Jin;Shin, Ra-Young
    • Journal of Korean Society on Water Environment
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    • v.34 no.4
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    • pp.375-381
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    • 2018
  • The monitoring of phytoplankton biomass and community structure is essential as a first step to control the harmful cyanobacterial blooms in freshwater systems, such as seen in rivers and lakes, due to the process of eutrophication and climate change. In order to quantify the biomass of phytoplankton with a wide range in size and shape, the measurement of cell biovolume along with cell density is required for a comprehensive review on this issue. However, most routine monitoring programs preserve the gathered phytoplankton samples before analysis using chemical additives, because of the constraint of time and the number of samples. The purpose of this study was to investigate the cell biovolume change characteristics of six cyanobacterial species, which are common bloom-causing cyanobacteria in the Nakdong River, after the preservation with Lugol's iodine solution. All species showed a statistically significant difference after the addition of Lugol's iodine solution compared to the live cell biovolume, and the cell biovolume decreased to the level of 34.0 ~ 56.3 % at maximum in each species after the preservation. The nonlinear regression models for determining the shrinkage ratio by a preservation period were derived by using the cell biovolume measured until 180 days preservation of each target species, and the equation to convert the cell biovolume measured after preservation for a certain period to the cell biovolume of viable cell was derived using that formula. The conversion equation derived from this study can be used to estimate the actual cell biovolume in the natural environment at the time of sampling, by using the measured biovolume after the preservation in the phytoplankton monitoring. Moreover this is expected to contribute to the final interpretation of the water quality and aquatic ecosystem impacts due to the cyanobacterial blooms.

Antibacterial Effect of Cinnamon (Cinnamomum cassia) Bark Extract against Fish Pathogenic Bacteria (계피 추출물의 어류 질병 세균에 대한 항균 효과)

  • MOK Jong-Soo;SONG Ki-Cheol;CHOI Nack-Joong;YANG Ho-Shik
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.5
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    • pp.545-549
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    • 2001
  • To develop a natural antibacterial agent for fish bacterial diseases, antibacterial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and bactericidal effect of cinnamon bark extract were examined against fish pathogenic bacteria. The antimicrobial effect of the extract to the fish diet was also estimated, Cinnamon bark extract showed the broad spectrum of antibacterial activity against fish pathogenic bacteria, especially, it had strong activity against Streptococcus iniae, Edwardsiella tarda and Listonella anguillarum. Its MIC was $75.8\sim189.6{\mu}g/mL$ against Cram positive bacteria, and $75.8\sim113.8{\mu}g/mL$ against Gram negative bacteria in liquid medium, It was found to show stronger bactericidal action against Gram negative bacteria than Cram positive bacteria. According to increasing concentrations of the extract, it resulted in a proportional reduction of viable cell counts of both S. iniae and L. anguillarum. The former was not detected by addition of $189.6{\mu}g/mL$ after 12 hours incubation and the latter by addition of $151.6{\mu}g/mL$ after 24 hours incubation, respectively. It was reasonable that fish diet was soaked in cinnamon bark extract for ten minutes. The relationship formula between the weight of fish diet and the extract absorbed to fish diet was Y=7.2726X+4.5083 ($R^2=0.9998$). The fish diet soaked in the extract inhibited the growth of all strains used in this study. Its antibacterial activity was stable at the range from $10^{\circ}C\;to\;35^{\circ}C$ during the storage period of 28 days. When the diet soaked in the extract was incubated in liquid medium at $35^{\circ}C$, it inhibited the growth of microorganisms inhabited in the diet.

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A Study on the Installation of Groyne using Critical Movement Velocity and Limiting Tractive Force (이동한계유속과 한계소류력을 활용한 수제 설치에 관한 연구)

  • Kim, Yeong Sik;Park, Shang Ho;An, Ik Tae;Choo, Yeon Moon
    • Journal of Wetlands Research
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    • v.22 no.3
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    • pp.194-199
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    • 2020
  • Unlike in the past, the world is facing water shortages due to climate change and difficulties in simultaneously managing the risks of flooding. The Four Major Rivers project was carried out with the aim of realizing a powerful nation of water by managing water resources and fostering the water industry, and the construction period was relatively short compared to the unprecedented scale. Therefore, the prediction and analysis of how the river environment changes after the Four Major Rivers Project is insufficient. Currently, part of the construction section of the Four Major Rivers Project is caused by repeated erosion and sedimentation due to the effects of sandification caused by large dredging and flood-time reservoirs, and the head erosion of the tributaries occurs. In order to solve these problems, the riverbed maintenance work was installed, but it resulted in erosion of both sides of the river and the development of new approaches and techniques to keep the river bed stable, such as erosion and excessive sedimentation, is required. The water agent plays a role of securing a certain depth of water for the main stream by concentrating the flow so much in the center and preventing levee erosion by controlling the flow direction and flow velocity. In addition, Groyne products provide various ecological environments by forming a natural form of riverbeds by inducing local erosion and deposition in addition to the protection functions of the river bank and embankment. Therefore, after reviewing the method of determining the shape of the Groyne structure currently in use by utilizing the mobile limit flow rate and marginal reflux force, a new Critical Movement Velocity(${\bar{U}}_d$) and a new resistance coefficient formula considering the mathematical factors applicable to the actual domestic stream were developed and the measures applicable to Groyne installation were proposed.

The First North Korean Painting in the Collection of the National Museum of Korea: Myogilsang on Diamond Mountain by Seon-u Yeong (국립중앙박물관 소장 산률(山律) 선우영(鮮于英) 필(筆) <금강산 묘길상도>)

  • Yi, Song-mi
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.97
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    • pp.87-104
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    • 2020
  • Myogilsang on Diamond Mountain, signed and dated (2000) by Seon-u Yeong (1946-2009), is the first work by a North Korean artist to enter the collection of the National Museum of Korea (fig. 1a). The donor acquired the painting directly from the artist in Pyeongyang in 2006. In consequence, there are no issues with the painting's authenticity.This painting is the largest among all existing Korean paintings, whether contemporary or from the Joseon Dynasty, to depict this iconography (see chart 1. A Chronological List of Korean Myogilsang Paintings.) It is ink and color on paper, measures 130.2 × 56.2 centimeters, and is in a hanging scroll format. Since this essay is intended as a brief introduction of the painting and not in-depth research into it, I will simply examine the following four areas: 1. Seon-u Yeong's background; 2. The location and the traditional appellation of the rock-cut image known as Myogilsang; 3. The iconography of the image; and 4) A comparative analysis of Seon-u Yeong's painting in light of other paintings on the same theme. Finally, I will present two more of his works to broaden the understanding of Seon-u Yeong as a painter. 1. Seon-u Yeong: According to the donor, who met Seon-u at his workshop in the Cheollima Jejakso (Flying Horse Workshop) three years before the artist's death, he was an individual of few words but displayed a firm commitment to art. His preference for subjects such as Korean landscapes rather than motifs of socialist realism such as revolutionary leaders is demonstrated by the fact that, relative to his North Korean contemporaries, he seems to have produced more paintings of the former. In recent years, Seon-u Yeong has been well publicized in Korea through three special exhibitions (2012 through 2019). He graduated from Pyeongyang College of Fine Arts in 1969 and joined the Central Fine Arts Production Workshop focusing on oil painting. In 1973 he entered the Joseon Painting Production Workshop and began creating traditional Korean paintings in ink and color. His paintings are characterized by intense colors and fine details. The fact that his mother was an accomplished embroidery specialist may have influenced on Seon-u's choice to use intense colors in his paintings. By 1992, he had become a painter representing the Democratic People's Republic of Korea with several titles such as Artist of Merit, People's Artist, and more. About 60 of his paintings have been designated as National Treasures of the DPRK. 2. The Myogilsang rock-cut image is located in the Manpok-dong Valley in the inner Geumgangsan Mountain area. It is a high-relief image about 15 meters tall cut into a niche under 40 meters of a rock cliff. It is the largest of all the rock-cut images of the Goryeo period. This image is often known as "Mahayeon Myogilsang," Mahayeon (Mahayana) being the name of a small temple deep in the Manpokdong Valley (See fig. 3a & 3b). On the right side of the image, there is an intaglio inscription of three Chinese characters by the famous scholar-official and calligrapher Yun Sa-guk (1728-1709) reading "妙吉祥"myogilsang (fig. 4a, 4b). 3. The iconography: "Myogilsang" is another name for the Bhodhisattva Mañjuśrī. The Chinese pronunciation of Myogilsang is "miaojixiang," which is similar in pronunciation to Mañjuśrī. Therefore, we can suggest a 妙吉祥 ↔ Mañjuśrī formula for the translation and transliteration of the term. Even though the image was given a traditional name, the mudra presented by the two hands in the image calls for a closer examination. They show the making of a circle by joining the thumb with the ring finger (fig. 6). If the left land pointed downward, this mudra would conventionally be considered "lower class: lower life," one of the nine mudras of the Amitabha. However, in this image the left hand is placed across its abdomen at an almost 90-degree angle to the right hand (fig. 6). This can be interpreted as a combination of the "fear not" and the "preaching" mudras (see note 10, D. Saunders). I was also advised by the noted Buddhist art specialist Professor Kim Jeong-heui (of Won'gwang University) to presume that this is the "preaching" mudra. Therefore, I have tentatively concluded that this Myogilsang is an image of the Shakyamuni offering the preaching mudra. There is no such combination of hand gestures in any other Goryeo-period images. The closest I could identify is the Beopjusa Rock-cut Buddha (fig. 7) from around the same time. 4. Comparative analysis: As seen in , except for the two contemporary paintings, all others on this chart are in ink or ink and light color. Also, none of them included the fact that the image is under a 40-meter cliff. In addition, the Joseon-period paintings all depicted the rock-cut image as if it were a human figure, using soft brushstrokes and rounded forms. None of these paintings accurately rendered the mudra from the image as did Seon-u. Only his painting depicts the natural setting of the image under the cliff along with a realistic rendering of the image. However, by painting the tall cliff in dark green and by eliminating elements on either side of the rock-cut image, the artist was able to create an almost surreal atmosphere surrounding the image. Herein lies the uniqueness of Seon-u Yeong's version. The left side of Seon-u's 2007 work Mount Geumgang (fig. 8) lives up to his reputation as a painter who depicts forms (rocks in this case) in minute detail, but in the right half of the composition it also shows his skill at presenting a sense of space. In contrast, Wave (fig. 9), a work completed one year before his death, displays his faithfulness to the traditions of ink painting. Even based on only three paintings by Seon-u Yeong, it seems possible to assess his versatility in both traditional ink and color mediums.

Studies on the Life History of Bacciger harengulae (Bacciger harengulae의 생활사에 관한 연구)

  • KIM Young-Gill;CHUN Seh-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.17 no.5
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    • pp.449-470
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    • 1984
  • The cercaria of Bacciger herengulae which is parasitized on the gonad of Solen strictus was investigated in order to reveal its entire life history. The area covered for the study was in the vicinity sea of Naechodo, the estuary of the Kum river in the western coast of Korea during the period of 1980-1983. Morphology and development as well as infection rates of sporocyst and cercaria within Solen strictus were examined. For accomplishing the objectives of this study, an artificial infection experiment and some investigations on the second intermediate host, the final host and the growing stages were also studied in both laboratory and natural habitat of Solen strictus. According to the study, it was revealed that the first intermediate hosts were Meretrix lusoria, Solen strictus, Tapes japonica and Laternula limicola, the second intermediate host was Palaemon (Exopalaemon) carinicauda and the final hosts were Konosirus punctatus and Harengula zunasi. A mature sporocyst which was found in the gonad of Solen strictus was $4.0-4.3{\times}0.2-0.21\;mm$ insize, and the cercaia with 27 pairs of setae, each seta consisting of 6 tufts, was $270{\times}147{\mu}m$ in body size and $550{\times}52{\mu}m$ in tail size. Oral sucker($52{\times}42{\mu}m$), pharynx, vental sucker and two testese were obviously seen within the cercaria. The excretory vesicles of cercaria were in V-shape and the flame cell were formula was expressed as 2[(3+3)+(3+3)]=24. The infection of cercaria in the first intermediate host, Solen strictus, was found throughout the year regardlless of the water temperature, and its mean infection rate was $9.67\%$ during the study period. The infection rate fluctuated with temperature, the highest being $28.0\%\;at\;28.0^{\circ}C$ water temperature in July and the lowest $2.4\%\;at\;19.5^{\circ}C$ in October, and it increased in proportion to the shell length on the host. But cercaria was not detected at below 4.0 cm in size of the host. Mature cercariae were found 6 months from May to October when water temperature was above $19.5^{\circ}C$. On the other hand, when water temperature was below $19.5^{\circ}C$, only immature cercariae and sporocysts were found. The cercariae were active for 35 hours and survived for 71 hours at $20^{\circ}C$, and 29 and 34 hours at $25^{\circ}C$ respectively, whereas the cercariae were inactive at less than $20^{\circ}C$ in water temperature. Cercaria, from Solen strictus, approached shrimp of 1-3 cm in body length as its second host. Then, it began to intrude in to the muscle of shrimp after 2-3 hours. The infected cercaria formed cyst after 7-8 hours, and became mature metacercaria. $420{\times}310{\mu}m$ in size, 15 days afer infection. The infection rate of metaceria to shrimp in the laboratory was highest, at $25^{\circ}C$ being $61\%$ and at $20^{\circ}C\;17%$. The infection rate of metacearia in shrimp was highest in the first abdominal segment, followed by cephalothorax, the second, and fifth abdominal segments, and in that order. Also, the infection rate of metacercaria in wild shrimp was high $9.6-11.1\%$ at $26.5^{\circ}C$ in June, and low $1.56-2.5\%$ at $28-29.5^{\circ}C$ from July to August. The infected shrimp with metacercaria was experimentally fed to Konosirus punctatus in the laboratory in order to know its final host. The metacercaria developed into the adult worm, $440-520{\times}310-360{\mu}m$ in size, within the intestine of Konosirus punctatus 20 days after infection. The adult worm was oval shape and $20-24{\times}11-20{\mu}m$ in size. The infection rate of adult worm to Konosirus punctatus and Harengula zunasi ranged 87.3 to $100\%$, the mean being $95.2\%$, regardless of the body length of their hosts. The infection rate was $100\%$ in June and July, but it decreased in September and October. The size and body structure of the trematode observed during the present study were well agreed with those ievestigated by Yamaguti(1938), thus, it may be concluded that the adult worm it identified as Bacciger harengulae.

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