• Title/Summary/Keyword: broken

Search Result 1,942, Processing Time 0.029 seconds

First-principles Study on the Half-metallicity and Magnetism of the (001) Surfaces of (AlP)1/(CrP)1 Superlattice ((AlP)1/(CrP)1 초격자계에서 (001) 표면의 자성과 반쪽금속성에 대한 제일원리 연구)

  • Bialek, Beata;Lee, Jae Il
    • Journal of the Korean Magnetics Society
    • /
    • v.25 no.6
    • /
    • pp.175-179
    • /
    • 2015
  • The half-metallicity and magnetism of the (001) surfaces of $(AlP)_1/(CrP)_1$ superlattice were investigated by means of FLAPW (Full-potential Liniarized Augmented Plane Wave) method. We considered four types of (001) surface termination, i.e., Al(S)-, Cr(S)-, P(S)Al(S-1)- and P(S)Cr(S-1)-term systems. We found that only Cr(S)-term system maintains the half-metallicity at the surface as only this system has the calculated magnetic moment of integer number of bohr magnetons. The magnetic moment of Cr(S) atom in the system was $3.02{\mu}_B$ which was increased from the bulk value by the effects of band narrowing and increased spin-splitting at the surface. The electronic density of states of the P(S) atom in the P(S)Al(S-1)-term showed very sharp surface states due to the broken $p_z$ bonds at the surface. We found there is still a strong p-d hybridization between the P(S) and Cr(S-1) layers in the P(S)Cr(S-1)-term which causes a considerable increase of magnetic moment of P(S) atom.

STUDIES ON THE TISSUE CULTURE OF PANAX GINSENG

  • Harn C
    • Proceedings of the Ginseng society Conference
    • /
    • 1974.09a
    • /
    • pp.9-22
    • /
    • 1974
  • Unlike the tissue culture in animals and human being, in higher plants various parts of the plant are cultured for varied purposes, and they are named variously depending on which parts are used as explants or what purposes they are cultured for. Followings are some of the names of culture used frequently: organ culture, tissue culture, callus culture, single cell culture, meristem culture, mericlone culture, ovary culture, ovule culture, embryo culture, endosperm culture, anther culture, pollen culture, protoplast culture, etc.. As the names of the culture indicate, in some kinds of culture the explants used for culture are actually not tissues, but organs, single cells, or protoplasts. It seems, however, convenient to call all of the above-mentioned cultures grossly as tissue culture. Several kinds of tissue culture were attempted using Panax ginseng as material and some of the results were summarized below. 1. Callus culture After dormancy of the sed was broken, whole embryo or parts (hypocotyl, cotyledon and epicotyl) of partly grown embryo were cultured in the media supplemented with growth regulators. Rapid swelling occurred in a few weeks, but most of the swelling was observed only in the basal part of epicotyl, changes in the other parts of embryo appearing in much later stages. The swelling or increase in size, however, was resulted not from the divisions of cells, but from the mere expansion of cell. Real calli were formed about two months after inoculation of explants. Callus tissues developed from cortex, pith, and vascular bundle in the cases of hypo- and epicotyl, from mesophyl tissue in the case of cotyledon. Shoots developed more easily from cotyledons regardless of whether they are detached from or attached to the embryo proper. 2. Culture in the Knudson C medium When cotyledons, detached from or attached to the embryo proper, were cultured in the growth regulator-free Knudson C medium comprision only several kinds of mineral compounds and sucrose, shoot primordium or callus developed profusely and finally plantlets were produced directly from shoot primordium or indirectly through callus. In this medium epidermal cells as well as mesophyl cells of the cotyledon became meristematic and divided, changing into multinucleate cells or multicellular bodies, developing eventually into either shoot primordia or calli. 3. Anther culture Anthers were cultured in the media supplemented with various growth regulators applied singly or in combinations. Callus was formed mostly in the connective tissue of anther. Cells of anther wall layers changed in appearance, but no division occurred. Microspores of all stages in development were not changed, ruling out the possibility that microspore-originated callus might be formed. 4. Isolation of protoplast Protoplasts were isolated from young root, leaf, and epicotyl, using 0.7M D-mannitols as osmoticum and using macerozyme and cellulase respectively for maceration and digestion of the cell wall. Production in large number of naked intact protoplast was rather difficult as compared with other plant species. Fusion of protoplasts occurred infrequently mainly due to the fewer number of naked protoplasts in the solution.

  • PDF

High Resolution Rainfall Prediction Using Distributed Computing Technology (분산 컴퓨팅 기술을 이용한 고해상도 강수량 예측)

  • Yoon, JunWeon;Song, Ui-Sung
    • Journal of Digital Contents Society
    • /
    • v.17 no.1
    • /
    • pp.51-57
    • /
    • 2016
  • Distributed Computing attempts to harness a massive computing power using a great numbers of idle PCs resource distributed linked to the internet and processes a variety of applications parallel way such as bio, climate, cryptology, and astronomy. In this paper, we develop internet-distributed computing environment, so that we can analyze High Resolution Rainfall Prediction application in meteorological field. For analyze the rainfall forecast in Korea peninsula, we used QPM(Quantitative Precipitation Model) that is a mesoscale forecasting model. It needs to a lot of time to construct model which consisted of 27KM grid spacing, also the efficiency is degraded. On the other hand, based on this model it is easy to understand the distribution of rainfall calculated in accordance with the detailed topography of the area represented by a small terrain model reflecting the effects 3km radius of detail and terrain can improve the computational efficiency. The model is broken down into detailed area greater the required parallelism and increases the number of compute nodes that efficiency is increased linearly.. This model is distributed divided in two sub-grid distributed units of work to be done in the domain of $20{\times}20$ is networked computing resources.

Development of Oxo-biodegradable Transparent Bio Films Using Biomass and Biodegradable Catalyst (바이오매스 및 생분해 촉매제를 이용한 산화생분해 투명 바이오 필름 개발)

  • You, Young-Sun;Kim, Young-Tae;Park, Dae-Sung;Choi, Sung-Wook
    • Clean Technology
    • /
    • v.23 no.2
    • /
    • pp.133-139
    • /
    • 2017
  • Bio-based plastics containing the biomass content higher than 25 wt% have been considered as environment-friendly materials due to their effects on the reduction in the $CO_2$ emission and petroleum consumption as well as biodegradability after use. In this study, poly vinyl chloride, plant-derived plasticizers, by adding a biodegradable catalyst was observed a change in the biodegradability and physical properties. To produce the oxidative decomposition transparent bio film, which is broken down in the initial percent elongation and physical properties such as tensile strength, it was to test the safety of the product as a food packaging material. Poly vinyl chloride, primary plasticizer, secondary plasticizer, anti fogging agent, the combined stabilizer were mixed in a high speed mixer, then extruded using an extrusion molding machine, after cooling, winding, to produce a oxidative decomposition transparent bio film and the control film, with a thickness of $12{\mu}m$ through winder role. Mechanical properties tensile strength, elongation, and the maximum load elongation and biodegradation test. Transparent bio film produced by biodegradation catalyst is compared with the control film. Tensile strength and elongation of films were found to be no significant difference. Further, as a result of the biodegradation test for 45 days based on the ASTM D6954-04 method, biodegrability of film is 61.4%.

The Changes of Socio-economic Environments of Rice- and Fruit-cultivated Area : In Case of Rural Villages in Sangju Region, Kyongsangbuk-do (미작과 과수 재배 지역의 사회와 경제 변화 : 상주권 농촌 촌락을 사례로)

  • Park, Kyu-Taeg
    • Journal of the Korean association of regional geographers
    • /
    • v.10 no.4
    • /
    • pp.744-756
    • /
    • 2004
  • The purpose of this study is to investigate the natural environments and the changing socio-economic activities of the rice and fruit - centered rural village located in Sangju region, Kyongsangbuk-do. Its results are summarized in the followings. Firstly, most of the rural villages in Sangju region is located on the erosional basin of Sobaek range and the sedimentary region of Nakdong river and the farmer's life of those regions has been influenced by such a natural environment. Secondly, the reproduction structure of population in the rural village of Sangju region had been maintained until the 1970s. After that, however, it was broken because the young generation of the rural villages moved to large cities to get a job or to receive high level of education. Thirdly, the changing path of the rural villages of Sangju region was different based on a type of crop and its related mode of production after the 1980s. The socio-economic structure of the rural village has been developed based on either a rice oriented traditional mode of production or a fruit-oriented commercial mode of production. The two villages, Ch'ekdong 1 ri, Hamch'ang-up and Sinch'on 2 ri, Modong-myon have been changed according to the path of a traditional and commercial mode of production, respectively.

  • PDF

The process of modernization of Geomundo during Japanese colonial period : focused on social structure (일제강점기 거문도 근대화 과정 -사회구조를 중심으로 -)

  • Park, Min Joung;Park, Soon Ho
    • Journal of the Korean association of regional geographers
    • /
    • v.22 no.1
    • /
    • pp.36-48
    • /
    • 2016
  • This paper analyzed the process of modernization in terms of the social structure in Geomundo. Before modernization, social structure in Geomundo was traditional society by a village unit. A village had community rituals and organization. There were independent parallel spatial structure among villages. In the early Japanese colonial period, 'forced modernization' had been occurred by Japanese immigrants settling in a separate living space. The modernization was transplanted in a new established village and diffused into other villages. In the process of forced modernization, the connection among villages was reinforced, as the result of that modern social organization was emerged, and the characteristics of community rituals had been changed. During modernization indigenization period, advanced fishery technology and distribution system occurred capitalist production system helping to place modern norms in the general daily life. In the late Japanese colonial period, aided organizations from local government and informal organizations reversed the trend of modernization through helping colonial exploitation policy. The spatial structure in Geomundo had become to hierarchical structure with intensified connectivity as the result of extensive spread of community territory. Modernization in Japanese colonial period was 'forced modernization' and could not re-established the community spirits. The community spirit has been broken up by dissolving the existing self regulating and self motivated organization.

  • PDF

Deterioration Analysis and Source Area on Rock Properties of the Seokgatap Pagoda in the Bulguksa Temple, Korea (불국사 석가탑의 풍화훼손도 분석 및 기원암의 산지추정)

  • Lee, Myeong-Seong;Lee, Chan-Hee;Suh, Man-Cheol;Choi, Seok-Won
    • 한국문화재보존과학회:학술대회논문집
    • /
    • 2004.10a
    • /
    • pp.15-24
    • /
    • 2004
  • The Seokgatap pagoda composed of mainly alkali granite and other minor pink-feldspar granite, fine-grained granite, granodiorite, diorite, gabbro, and tuff. Despite the small loss and damage derived from joints, its peel-off and exfoliation are serious enough to cause the heavy deterioration on the stone surface. The chemical and petrological weathering has partly replaced the original rock-forming minerals with clay minerals and iron oxyhydroxides. Based on the petrogenesis, rock materials of the pagoda is very similar to rocks of Dabotap pagoda and the Namsan granite in the Gyeongju. The central fart of the pagoda has sunken highly, which caused all the corners to split and the structural transformation to become worse. The reverse V-shaped gaps between the materials have broken stones filled in a coarse way. The iron plates inserted between the upper flat stone laid on other stones and tile pagoda body in the north and east side has been exposed in the air and corroded, discoloring of the adjacent stones. The overall diagnosis of the Seokgatap pagoda is the deteriorated functions of the stone materials, which calls for a long-term monitoring and plans to reinforce the stone surfaces. But the main body including the pagoda roof stone needs washing on a regular basis, and the many different cracks should be fixed with glue by using the fillers or hardeners designed for stone cultural properties after removing the cement mortar. In case of the replacement of the stone materials with new stones, it's necessary to examine the pagoda for the center of gravity and support intensity of the materials. The structural stability of the pagoda can be attained by taking a reinforce measure in geotechnical engineering and making a drainage. The ground humidity, which has aggravated weathering and structural instability, should be resolved by setting up a humidity reduction facility. The contamination of lichens and bryophyte around the pagoda and on the surface is serious. Thus biochemical treatments should be given too in order to prevent further biological damages and remove the vegetation growing on the discontinuous planes.

  • PDF

Material Characteristics and Quantitative Deterioration Assessment of the Sinwoldong Three-storied Stone Pagoda in Yeongcheon, Korea (영천 신월동삼층석탑의 재질특성과 훼손도 정량평가)

  • Yi, Jeong-Eun;Lee, Chan-Hee;Chae, Seong-Tae;Jung, Young-Dong
    • Journal of Conservation Science
    • /
    • v.26 no.4
    • /
    • pp.349-360
    • /
    • 2010
  • The Yeongsheon Sinwoldong three-storied stone pagoda (Treasure No. 465) composed mainly of drusy alkali-granite. The major rock-forming minerals are biotite, quartz, amphiboles, orthoclase and plagioclase. Yellowish brown and black discoloration are formed at the eight sculpture Buddha of the stylobate. A broken rock fragments in the roof material were repaired using epoxy resin and cement mortar in the past. As a result of the infrared thermography analysis from the pagoda, cracks and exfoliation were not serious. Also, P-XRF analysis showed that concentration of Fe (mean 5,599ppm) and S (mean 3,270ppm) were so high in yellowish discoloration parts. Black discoloration area was detected highly Mn (mean 2,155ppm) concentration around the eight sculpture Buddha of the stylobate. The main reason for these are inorganic contaminants from disengaged rock ingredient and organic contaminants from withered plant body. Degree of physical weathering is relatively high in the southern and northern side. The eastern and western side had similar with weathering condition. The northern and eastern side were serious discoloration and biological weathering relatively. Therefore, we suggest that the pagoda need to do cleaning of biological contaminant and conservation treatment to weakened materials of rock and long term monitoring.

Characteristics of Barley Polyphenol Extract (BPE) Separated from Pearling By-products (보리 도정부산물로부터 분리한 폴리페놀 추출물의 특성)

  • Seog, Ho-Moon;Seo, Mi-Sook;Kim, Sung-Ran;Park, Yong-Kon;Lee, Young-Tack
    • Korean Journal of Food Science and Technology
    • /
    • v.34 no.5
    • /
    • pp.775-779
    • /
    • 2002
  • Barley brans, divided into fractions I $(pearlers\;1{\sim}4)$, II $(pearlers\;5{\sim}20)$, and III $(pearlers \;21{\sim}24)$, germ, and broken kernels were collected as pearling by-products produced by an industrial process consisting of 24 consecutive barley pearlers. The pearling by-products were extracted with 75% ethanol, and polyphenol extracts were separated using Sepabeads SP-850 resin. Total polyphenol content was the highest (43.68%) in the polyphenol extract separated from fraction I. Polyphenol compounds analyzed by HPLC were tentatively identified as proanthocyanins and prodelphinidin polymers, which were known to have antioxidative and antimutagenic activities. Antioxidative abilities were estimated to be in the following order: fraction I>germ>fraction II>fraction III. At 0.01% polyphenol extract, angiotensin I-converting enzyme inhibitory activity was the highest in the germ fraction (40.04%). Nitrite-scavenging activity was over 70% in all fractions. Superoxide dismutase-like activity was in the range of $64{\sim}78%$ in fractions I and II.

Production of Starch Vermicelli (Dangmyun) by Using Modified Corn Starches (I) -Physicochemical Properties of Domestic and Foreign Starch vermicelli (Dangmyun)- (변성 옥수수 전분을 이용한 당면제조 (I) -국내외 시판당면의 이화학적 특성-)

  • Yook, Cheol;Lee, Won-Kun
    • Korean Journal of Food Science and Technology
    • /
    • v.33 no.1
    • /
    • pp.60-65
    • /
    • 2001
  • Physicochemical properties of 4 kinds of domestic and 7 kinds of foreign starch vermicelli (1 from Chinese, 6 from Japan) were determined. Peak temperature of starch vermicelli measured by DSC were $42{\sim}48^{\circ}C$ which were much lower than gelatinization temperatures of their raw material starches. X-ray diffraction peaks of starch vermicelli were not sharp compared with those of raw material starches which indicated that starches were gelatinized by heating and retrograded by cooling and freezing during production of starch vermicelli. Hardness and compression slope of sweet potato starch vermicelli measured by rheometer were respectively $9,500{\sim}11,000\;g/cm^2$ and $18,000{\sim}26,000\;g/cm^2$ which were twice higher than those of corn starch vermicelli. Cooking loss of corn starch vermicelli, which was 19.8%, was higher than that of sweet potato starch vermicelli, $4.2{\sim}6.6%$ and mung bean starch vermicelli, 7.7%. In changes of thickness of starch vermicelli during cooking i.e swelling ratio, sweet potato starch vermicelli had $58{\sim}69%$ of swelling ratio, which was higher than that of corn starch vermicelli, 50%. Corn starch vermicelli, which was relatively less elastic and easily broken, was shown to be inferior to that of sweet potato starch vermicelli in overall quality.

  • PDF