• Applied Microscopy
• /
• v.25 no.4
• /
• pp.83-103
• /
• 1995

This experiment was carried out to investigate the effects of telluric acid on the histological and fine structural changes in the rat liver. Fischer 344 rats($150{\sim}200gm$) were used in this study as control and experimental groups. Telluric acid(5 mg/100 gm of body weight) suspensed in olive oil was given intraperitoneally to the animals of the experimental group and only olive oil to those of the control group. At the intervals of 3, 6 and 12 hours, 1, 2, 3, 5, 10, 20, 30 and 60 days after administration, the animals were sacrificed, and livers were obtained from the rats. For light microscopic examination of the liver, sections($5{\mu}m$) were stained with hematoxylineosin(H-E). For electron microscopic examination of the liver, sections were stained with uranyl acetate and lead citrate, finally examined with Zeiss EM 109 electron microscopes. The results obtained were as follows. 1. In the control group, round nucleus. well developed mitochondria, Golgi apparatus, rough endoplasmic reticulum(RER) and numerous glycogen particles were observed in the cytoplasm of the hepatocyte. In the cytoplasmic membranes of the hepatocyte, sinusoidal surface had numerous microvilli and cellular surface is combinated adjacent hepatocyte with desmosomes. The RER cisterns were dilated and zymogen granules were fewer than those of the dark cells. Kupffer cells with irregular nuclear membrane were observed. Fat storing cell and collagenous fiber bundle were observed in the Disse space. 2. Kupffer cell, inflammatory cells in the connective tissue of hepatic triad and lysosome were increased in the 3, 6, and 12 hour experimental group comparing with that of the control group. 3. In the 1 day experimental group, infiltration of inflammatory cells in interlobular connective tissue, dilatation of sinusoidal capillary and increasing of Kupffer cell were observed. Atropic change of hepatocyte and aggregation of glycogen particles in the cytoplasm of hepatocyte were observed. In this group, desmosome near bile canaliculi and collagenous fiber bundle in the Disse space were increased comparing with that of the 12 hours experimental group. In the 2 days experimental group, desmosome, lysosome, peroxisome and collagenous fiber bundle were increased comparing with that of the 1 day experimental group. Furthermore, lamellated bodies were also seen in the cytoplasm of the hepatocyte. 4. In 3 and 5 days experimental groups, transformations of hepatic cell cord and degeneration of the hepatocyte were markedly inclosed comparing with the all experimental groups. And damaged RER and mitochondria. collagenous fiber bundle were also inclosed comparing with that of the 2 days experimental group. Autophagosome and fat storing cells with large lipid droplets were also observed comparing with that of the 2 days experimental group. Tight junction and desmosome between the hepatocytes were separated. These degenerating changes were severe through the all experimental groups. 5. In the 10 and 20 days experimental groups, arrangement of hepatic cell cords and cell organelles of hepatocytes were similar to those of the control group. However, aggregation of glycogen particles, dilatation of sinusoidal capillary and infiltration of inflammatory cells remained. 6. In the 30 days experimental group, the tissue findings were similar to those of the control grout. But lamellated bodies in some hepatocytes and lysosome were remained in the cytoplasms of the Kupffer cells. In the 60 days experimental group, these all changes were recovered as the control group. In conclusion, telluric acid would directly induce the degenerative and necrotic changes on the hepatic tissue. However, these changes were perfectly recoverd in the 60 days experimental group as the control group.

• Restorative Dentistry and Endodontics
• /
• v.22 no.1
• /
• pp.1-33
• /
• 1997

The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.38 no.3
• /
• pp.23-32
• /
• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• Journal of Environmental Health Sciences
• /
• v.10 no.2
• /
• pp.9-40
• /
• 1984

This thesis purports to overview the diverse administrative and organizational factors and plannings developed by the government organizations, municipal or otherwise, to tackle the Han River water pollution issues in the past years. This thesis also looks into the ever-worsening Han River water pollution problems, in particular, in terms of the various government plans ostensibly designed to reduce the pollution level but with little success. Also dealt with are the efficiencies with which the laws and decrees on water pollution the administrative organizations put to use in the prosecution of the diverse antiwater pollution projects involving the Han River basin. From the early 1960's up to the 1970's the government had concentrated on the growth-oriented economic policy with the result that little attention had been paid to the water pollution and other environmental issues that are bound to arise from the massive economic growth. Belatedly, the five-year Hah River Development Project was initiated in 1982 with emphasis on reducing the water pollution level at Hah River to the minimum. The following are the gists of the thesis and recommendations for the future antiwater pollution plans by the administrative organizations: 1. Documents to date indicate that the irrigation projects along the Han River area had been the main focus of attention during the Yi Dynasty and under the Japanese rule of the country. 2. Despite that the water pollution issue became the subject of many debates among the academic and research institutions in the 1960's and in the 1970's, the administrative organizations in charge of the Han River water quality control failed to come up with a concrete plan for the river's water quality control. 3. Nevertheless, the water pollution of the Han River area in fact began in the 1950's, with the unprecedented concentration into Seoul of population and the industrial facilities on a larger scale, in particular, enforced by the government's strong growthoriented policy in its Economic Development plans in the 1960's. 4. Starting in the 1960's, the Han River water pollution level dramatically increased, but the government was reluctant to promulgate or put into effect strong measures to curb the many factors contributing to the river water pollution, thus worsening the environmental issues along the Han River basin. 5. The environmental protection law and other laws and decrees relating to the antiwater and air pollution issues that were subsequently put into effect underwent so many changes that efficient anti-water pollution policies could not be effected for the Han River basin. The frequent organizational reshuffle within the administrative units concerned with environmental problems has resulted in the undue waste in personnel management and finance. 6. The administration on the environmental protection could not be efficiently carried out due to the organizational overlapping. Under the existing law, frequent organizational frictions and inefficiency are bound to occur among the central government offices themselves, as well as between the central government and the Seoul city administration, and among the city's administrative offices over the conservation of the Han River basin and over the river's anti-water pollution issue. 7. In the planning and prosecution of the Han River project, political influences from the president down to the lower-level politicious appear to have been involved. These political influences in the past had certainly had negative influence on the project, nevertheless, it appears that in the recent years, these political influences are not all that negative in view of the fact that they serve as a positive contributing factor in developing a better water quality control project along the Han River basin. The following are a few recommendations based on the data from the thesis: First, officials in charge of the Han River water quality control should pay attention to a careful screening of the opinions and recommendations from the academic circles and from the public should be made so that the government could better grasp the core issues in the environmental problems that require preventive and other necessary measures. Second, vigorous redistribution policies of population and industrial facilities away from the Seoul area should be pursued. Third, the government should refrain from revising or revamping too frequently the laws and decrees on the anti-water pollution, which is feared to cause undue inconveniences in the environmental administration. Fourth, a large-scale streamlining should be made to the existing administrative organization in an effort to do away with the inter- and intra-organizational friction. It is recommended that a secretariat for the Hah River basis conservation be established. Fifth, High-level administrative officials, with a thorough knowledge and vision on the Han River water quality control, should be prepared to better deal with the budgeting and personnel management for the Han River water pollution control not only at the control government, but also at the Seoul city municipal government levels. Environmental issues should be kept distinct from political issues. Environmental issues should not serve as a window-dressing for sheer political purposes. Sixth, the Hah River proiect should also include, along with the main Han River basin, those areas covering North Han River, South Han River, and the tributaries to the main river basin. The 'Han River Basin Water Quality Control Board' should be established immediately as a means of strengthening the current Han River basin water quality control policy. Seventh, in drawing up the Han River proiect, the administrative officials should be aware that Han River basin is a life line for those people in the region, providing them with not only a sheer physical space, but with a psychological living space for their everyday life.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.3
• /
• pp.1-11
• /
• 2012

This study focused on establishing a natural rainwater circulation system using rainwater meant for relatively large urban development projects such as a new town development. In particular, when the location selection techniques for individual elements of a natural rainwater circulation system are developed for the integrated rainwater management, changes in hydrological environment will be minimized and the natural water circulation would be restored to realize the low impact development (LID). In that case, not only the excess will be reduced but water space and green areas in a city would also increase to improve the urban sustainability. First of all, there were five elements selected for the location selection of a rainwater circulation system intended for the integrated rainwater management: rainwater collection, infiltration, filtration, retention and movement spaces. After generating these items, the location selection items and criteria were defined for each of the five elements. For a technique to apply the generated evaluation items and criteria, a grid cell analysis was conducted based m the suitability index theory, and thematic maps were overlapped through suitability assessment of each element and graded based on the suitability index. The priority areas were identified for each element. The developed technique was applied to a site where Gim-cheon Innovation City development is planned to review its feasibility and limitations. The combined score of the overlapped map for each element was separated into five levels: very low, low, moderate, high and very high. Finally, it was concluded that creating a rainwater circulation system conceptual map m the current land use plan based on the outcome of the application would be useful in building a water circulation system at the de1ailed space planning stage after environmental and ecological planning. Furthermore, we use the results of this study as a means for environment-friendly urban planning for sustainable urban development.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.31 no.4
• /
• pp.95-112
• /
• 2013

Jangchungdan Park is now perceived as a mere park at the foot of Namsan mountain, but originally it was created to commemorate soldiers of Korean Empire on a site which name was Namsoyeong(南小營) during Joseon Dynasty. During the period of Japanese colonial rule, it was transformed into a park due to the rapidly changing circumstances, so the components expressing the validity of the colonial rule were introduced into the park. This paper examines the time sequential changes of Jangchungdan Park during the period of Japanese colonial rule, and the conclusions can be summarized as given below. Firstly, the park originally was a space to commemorate the soldiers who fought for the Korean Empire. It was built on formerly restricted area at the foot of Namsan Mountain in 1900, and it was arranged putting the ceremonial shrine Dansa (壇祠) as a central building and the annexes in the surroundings of it. The memorial ceremonies were held regularly in spring and autumn until 1909. Secondly, it became a city park for citizens of Gyeongseong-bu(the name of Seoul under the Japanese colonial rule). The authorities of Gyeongseong-bu reorganized Jangchungdan as a park in 1919, prohibited the performance of memorial ceremonies, and the existing buildings except the ceremonial shrine Dansa began to be used as park management facilities. Resting areas and amenities were supplemented for the usage of people from various backgrounds, and the large scale planting of cherry trees made the park a famous place to enjoy cherry-blossoms and other flowers in spring. Thirdly, it was reconstructed as a space to honor the influential personalities of Japanese colonial system. In 1932, Bankmun temple (博文寺) to commemorate Ito Hirobumi was constructed at a location that made it possible for a number of people to overlook Jangchungdan area. During that time, the buildings of traditional Joseon architecture were removed and reconstructed to serve as annexes to Bankmun temple. Due to the strategy to make Jangchungdan park a tourist attraction, Bankmun temple was included into the Gyeongseong sightseeing course, since the wide panorama of Jangchungdan Park and the whole city of Gyeongseong was opening from the temple. Various different components were introduced into Jangchungdan Park due to the rapidly changing circumstances; therefore the nature of the park was either altered or reproduced. Hopefully, the park rearrangement works will be executed paying respects to the memories of the past hereafter.

• Korean Journal of Remote Sensing
• /
• v.17 no.1
• /
• pp.33-44
• /
• 2001

The paper presents several satellite models and satellite image decomposition methods for inaccessible area where ground control points can hardly acquired in conventional ways. First, 10 different satellite sensor models, which were extended from collinearity condition equations, were developed and then behavior of each sensor model was investigated. Secondly, satellite images were decomposed and also pseudo images were generated. The satellite sensor model extended from collinearity equations was represented by the six exterior orientation parameters in $1^{st}$, $2^{nd}$ and $3^{rd}$ order function of satellite image row. Among them, the rotational angle parameters such as $\omega$(omega) and $\Phi$(phi) correlated highly with positional parameters could be assigned to constant values. For inaccessible area, satellite images were decomposed, which means that two consecutive images were combined as one image, The combined image consists of one satellite image with ground control points and the other without ground control points. In addition, a pseudo image which is an imaginary image, was prepared from one satellite image with ground control points and the other without ground control points. In other words, the pseudo image is an arbitrary image bridging two consecutive images. For the experiments, SPOT satellite images exposed to the similar area in different pass were used. Conclusively, it was found that 10 different satellite sensor models and 5 different decomposed methods delivered different levels of accuracy. Among them, the satellite camera model with 1st order function of image row for positional orientation parameters and rotational angle parameter of kappa, and constant rotational angle parameter omega and phi provided the best 60m maximum error at check point with pseudo images arrangement.

• Publications of The Korean Astronomical Society
• /
• v.36 no.3
• /
• pp.65-78
• /
• 2021

Jagyeokru, an automatic striking water clock described in the Sejong Sillok (Veritable Records of King Sejong) is essentially composed of a water quantity control device and a time-signal device, with the former controlling the amount or the flow rate of water and the latter automatically informing the time based on the former. What connects these two parts is a signal generating device or a power transmission device called the 'Jujeon' system, which includes a copper rod on the float and ball-racked scheduled plates. The copper products excavated under Gongpyeong-dong in Seoul include a lot of broken plate pieces and cylinder-like devices. If some plate pieces are put together, a large square plate with circular holes located in a zigzag can be completed, and at the upper right of it is carved 'the first scheduled plate (一箭).' Cylinder-like devices generally 3.8 cm in diameter are able to release a ball, and have a ginkgo leaf-like screen fixed on the inner axis and a bird-shaped hook of which the leg fixes another axis and the beak attaches to the leaf side. The lateral view of this cylinder-like device appears like a trapezoid and mounts an iron ball. The function of releasing a ball agrees with the description of Borugak Pavilion, where Jagyeokru was installed, written by Kim Don (1385 ~ 1440). The other accounts of Borugak Pavilion's and Heumgyeonggak Pavilion's water clocks describe these copper plates and ball releasing devices as the 'Jujeon' system. According to the description of Borugak Pavilion, a square wooden column has copper plates on the left and right sides the same height as the column, and the left copper plate has 12 drilled holes to keep the time of a 12 double-hours. Meanwhile, the right plate has 25 holes which represent seasonal night 5-hours (Kyeong) and their 5-subhours (Jeom), not 12 hours. There are 11 scheduled plates for seasonal night 5-hours made with copper, which are made to be attached or detached as the season. In accordance with Nujutongui (manual for the operation of the yardstick for the clepsydra), the first scheduled plate for the night is used from the winter solstice (冬至) to 2 days after Daehan (大寒), and from 4 days before Soseol (小雪) to a day before the winter solstice. Besides the first scheduled plate, we confirm discovering a third scheduled plate and a sixth scheduled plate among the excavated copper materials based on the spacing between holes. On the other hand, the width of the scheduled plate is different for these artifacts, measured as 144 mm compared to the description of the Borugak Pavilion, which is recorded as 51 mm. From this perspective, they may be the scheduled plates for the Heumgyeonggak Ongru made in 1438 (or 1554) or for the new Fortress Pavilion installed in Changdeokgung palace completed in 1536 (the 31^st year of the reign of King Jungjong) in the early Joseon dynasty. This study presents the concept of the scheduled plates described in the literature, including their new operating mechanism. In addition, a detailed model of 11 scheduled plates is designed from the records and on the excavated relics. It is expected that this study will aid in efforts to restore and reconstruct the automatic water clocks of the early Joseon dynasty.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.39 no.2
• /
• pp.1-14
• /
• 2021

Ssangsanjae was created in the mid-1800s, It is located at Jiri Mountain to the north and the Seomjin River to the south. This garden has not changed much even though it has passed through the sixth generation since its creation, so it still retains the features of a private garden in the late Joseon Dynasty. This study focused on the changing landscape of Ssangsanjae as a historical garden; through field surveys, interviews and analysis of builder's collection, boards and couplets. Ssangsanjae is largely classified into inner and outer gardens, and the inner is divided into an entry space, a residential space, and a backyard. The backyard consists of Seodangchae, it's garden, Gyeongamdang, and swimming pool, and is connected to the Sado Reservoir area, which is the outer garden. The distinct vegetation landscape of Ssangsanjae are a 13,000m² bamboo and green tea field, Peony(Paeonia suffruticosa Andr. and Paeonia lactiflora var. trichocarpa(Bunge) Stern) planted on both sides of the road that crosses the lawn, the view through a frame(額景) shown by the twisted branches of Camellia and Evergreen spindletree, and a fence made of Trifolia Orange(Poncirus trifoliata) and Bamboo. Ssangsanjae stands out for its spatial composition and arrangement in consideration of the topography and native vegetation. The main building was named by the descendants based on the predecessor's Aho(pseudonym), and it is the philosophical view of the predecessors who tried to cultivate the younger students without going up on the road. The standing stone and white boundary stone built by Mr. Oh Ju Seok are Ssangsanjae's unique gardening facilities. The stone chairs, and swimming pool which were created by the current owner for the convenience of families and visitors also make a distinctive landscape. Ssangsanjae, for residents, was a place for living, exchanging friendships, training himself and seculusion, for children was a place for learning, but now is 'the private garden' where many people can heal themselves. Over the 200 years, the landscape of Ssangsanjae's inner and outer gardens experienced large and small changes. As such, it is necessary to recognize the historical gardens with changing properties as a living heritage. This study is significant in that, as the first study to approach Ssangsanjae in the view of landscape research, it provides basic data on Ssangsanjae as a destination of garden tourism.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.3
• /
• pp.110-125
• /
• 2017

The purpose of this study is to investigate the constructional facts and the operational features of Hamchunwon(含春苑), a wonyu(苑?, a royal garden) constructed in Dongbu(Eastern District) of the capital city of Hanyang. As the living quarters of the queen dowagers were scheduled for relocation after the construction of Changgyeonggung Palace(昌慶宮) during the reign of King Seongjong(成宗), it is presumed that the screening tree planting project discussed around tongmangcheo(通望處, a place allowing open view) was the original form of Dongbu Hamchunwon. Dongbu Hamchunwon was a longitudinal royal garden built in the area across the section from Wolgeunmun Gate(月覲門) to Seoninmun Gate(宣仁門), which were both attached to the east side walls of Changgyeonggung Palace. The area corresponds to the west side area of the newly built main building of Seoul National University Hospital today. During the Joseon Dynasty, only royal gardens built within a palace were referred to as geumwon(禁苑, a palace garden). But Dongbu Hamchunwon which was built outside a palace was recognized as a symbolic and hierarchical space comparable to geumwon. The site location of Donbu Hamchunwon was an important place that corresponded to Naecheongnyong(內靑龍) according to Hanyang's geomancy, and large-scale public works were prohibited in order to protect the vein of Naecheongnyong. During the reign of King Injo(仁祖), part of Dongbu Hamchunwon was partitioned as a ranch. The area around the ranch was called Madongsan(馬東山) and Bangmawon(放馬苑) and was an open space used for rest and pleasure (amusement). In the early days of Hamchunwon's construction, fast growing trees were planted to screen the view to Changgyeonggung Palace. However, after the construction of Gyeongmogung Shrine(景慕宮), a broad scale tree planting project was undertaken to complement Naecheongnyong's vapor of the earth. In particular, after the construction of Yugeunmum Gate(?覲門) and Yucheommun Gate(?瞻門) during the reign of King Jeongjo(正祖), Dongbu Hamchunwon functioned as a key point on the King's progress for paying respects to the ancestors, which followed the route of Palace(Changgyeonggung)-Wonyu(Hamchunwon)-Ancestral Shrine(Gyeongmogung).