카올린으로부터 합성된 고순도 알루미나의 γ→α변태에 미치는 Fe₂O₃첨가의 영향

강효경,박성수,박희찬 釜山大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.53 No.-

국내산 카올린으로부터 알루미늄황산염수화물을 합성하고, 이의 특성 및 열분해에 따른 알루미나의 γ→α변태에 미치는 Fe₂O₃의 첨가효과가 X-선회절분석, 시차열중량분석, 주사전자현미경, 플라즈마분광분석, BET법을 이용하여 검토하였다. 합성된 2 ㎛정도 크기의 판상입자형태로 구성된 고순도 알루미늄황산염은 Al₂(SO₄)₃·18H₂O로 동정되었으며, 이는 150℃ 부근에서의 탈수반응과 750℃부근에서의 탈황산반응을 경유하여 1000℃에서 결정성이 낮은 γ-Al₂O₃로 변화하였고, γ→α변태는 1200℃정도에서 일어났다. 0.1 wt% Fe₂O₃를 첨가한 경우의 1200℃하소물에서 생성된 FeAl₂O₄스피넬은 알루니마의 γ→α변태를 억제시켰으며, 그 이상의 양을 첨가한 경우와 1300℃로의 하소온도를 증가시킨 경우는 FeAl₂O₄의 α-Al₂O₃와 Fe₂O₃로의 분해 및 이온확산속도의 증가로 인하여 α-Al₂O₃생성이 촉진되었다. Aluminum sulfate hydrate has been prepared from the domestic kaolin, and its characteristics and the effect of Fe₂O₃addition on the γ→αtransformation of the resulting alumina have been investigated by means of the XRD, TG/DTA, SEM, plasma spectrometer, and BET methods. The aluminum sulfate having high purity and 2 ㎛-sized plate-like structure particles was identified as a crystalline Al₂(SO₄)₃·18H₂O, and decomposed to γ-Al₂O₃at 1000℃ via dehydration at ∼150℃ and desulfurization at ∼750℃. γ-Al₂O₃transformed to α-Al₂O₃at 1200℃. After calcination of the aluminum sulfate with addition of 0.1 wt% Fe₂O₃at 1200℃, the formation of FeAl₂O₄spinel prohibited the γ→αtransformation of the alumina. However, the addition of > 0.1 wt% Fe₂O₃and the increase in calcination temperature to 1300℃ accelerated the γ→αtransformation, due to the decomposition of FeAl₂O₄to α-Al₂O₃and Fe₂O₃and the velocity of ion diffusion, respectively.

카올린으로부터 액상침전법에 의한 미립 알루미나 합성

박희찬,강효경,김병찬,박성수 釜山大學校生産技術硏究所 1999 生産技術硏究所論文集 Vol.56 No.-

카올린으로부터 미립 일루미나 분말을 합성하였다. 황산용액을 이용하여 액상침전법으로 알루미나를 추출하였다. 알루미나 추출에 미치는 황산농도, 반응온도 및 반응시간의 영향을 조사하였다. 이 과정에서 수화 황산알루미늄이 용출액으로부터 석출되었다. 이때 석출제로는 에탄올을 사용하였다. 이 석출물을 가영하여 미립 알루미나 분말을 얻을 수 있었다. DTA, SEM, TEM 및 XRD를 이용하여 분말의 특성을 조사하였다. Fine alumina was synthesized from kaolin. The alumina was prepared by liquid phase precipitation method using H?SO? solution. The effects of acid concentration, reaction temperature and reaction time on alumina extraction were investigated. Using an ethanol as precipitating agent, hydrated aluminum sulfate was precipitated from leach liquor. Fine alumina powder was obtained by calcining the precipitate. DTA, SEM, TEM and XRD were employed to characterize the powder.

BaFBr:Eu²+,Na+ 영상판 제작과 특성

김찬중,김성환,이병화,김완,강희동,김도성,서효진,도시홍 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

BaFBr:Eu^2+ 형광체의 열발광 및 광자극발광 특성

도시홍,서효진,강갑중,김영국,김도성,김성환,김찬중,이병화,김완,강희동 한국센서학회 2002 센서학회지 Vol.11 No.5

BaFBr:Eu^2+ 형광체를 제조하고, 이 형광체의 열발광 특성과 광자극발광 특성을 조사하였다. 이 형광체의 열발광 g1ow 피이크 온도는 352K와 448K였으며, 주 피이크(352K)에 관여하는 트랩의 활성화에너지는 약 0.96eV이었다. 또한 이 형광체의 광자극발광 스펙트럼의 파장범위는 350~450nm 사이였으며, 광자극발광에 기여하는 트랩의 활성화에너지는 약 0.98eV이었다. 열발광트랩과 광자극발광 트랩의 활성화에너지는 실험오차 내에서 일치하였다. BaFBr:Eu^2+ phosphors were prepared, and the thermoluminescence(TL) and photostimulatedluminescence(PSL) of the prepared phosphors were measured. Two glow peaks around 352 and 448 K are observed for x-ray irradiated BaFBr:Eu^2+ phosphors, and the activation energy of the main glow peak(352 K) was about 0.96 eV. The spectral range of the PSL was 350 ~450 nm, and the activation energy of the trap giving rise to PSL was about 0.98 eV. The activation energy of the traps giving rise to TL is agreed to those giving rise to PSL within experimental error.

SrCI_2:Eu^2+ 형광체의 광발광 및 광자극발광 특성

도시홍,서효진,김영국,김도성,김성환,김찬중,이병화,김완,강희동 한국센서학회 2002 센서학회지 Vol.11 No.6

고상반응법으로 SrCl_2:Eu^2+ 형광체를 제작하고, 제작한 형광체의 광자극발광과 광발광 특성을 조사하였다. SrCl_2:Eu^2+ 형광체와 광발광 및 광자극발광은 Eu^2+ 의 5d->4f 천이에 기인되었으며, 355 nm의 광으로 여기시켰을 때 광자극발광과 광발광 스펙트럼의 파장범위는 모두 380~440nm이었고, 피이크 파장은 407nm이었다. SrCl_2:Eu^2+형광체의 선량의존성은 2.5 mGy~200mGy영역에서 우수한 선형성을 나타내었으며, 상온에서 광자극발광의 fading은 20분에 60%이었다. SrCl_2:Eu^2+ phosphors were prepared by the solid phase reaction method, and their photostimulated luminescence(PSL) and photoluminescence(PL) characteristics were investigated. The PSL and PL peak of the SrCl_2:Eu^2+ phosphors are due to the 5d->4f transition of Eu^2+ ions in phosphors. The PSL and PL spectrum obtained by the 355 nm exitation was observed in 380~440 nm region with the peak at 407 nm. The dose response of the PSL phosphors were linear within 2.5 mGy ~ 200 mGy of 100kV X-ray. The fading of the phosphors at room temperature was approximately 60% after 20 min.

흰쥐의 방사선 피폭후 생물학적 지표로서의 혈액효소

김진규,김상복,김국찬,천기정,김인규,박효국,이강석 대한방사선 방어학회 1993 방사선방어학회지 Vol.18 No.2

생물학적 선량평가를 위한 생화학적 지표 연구로서 흰쥐 혈액내 효소활성도의 변화를 조사한 결과는 다음과 같다. 1) Alkaline phosphatase 활성도는 0.1, 0.25, 0.5, 2, 4 Gy의 방사선 조사후 24시간까지 혈액내 활성도가 증가하였고 72시간 경과시에는 대조군과 비슷한 활성도를 보였다. Creatine kinase는 2, 4 Gy 방사선 조사후 혈액내에서 활성도에서 활성도가 72시간까지 증가하였으나 0.1, 0.25Gy, 0.5 Gy 방사선 조사시에는 커다란 변화를 보이지 않았다. 2) Malate dehydrogenase 활성도는 0.1, 0.25, 0.5 Gy 방사선 조사시에는 커다란 변화가 없었으며 lactate dehydrogenase는 방사선 조사후 활성도가 감소하였다. 3) GOT의 활성도는 선량률 0.1Gy/min.로 0.1, 0.25, 0.5, 2, 4 Gy 조사후에는 어떠한 변화도 없었으며 선량률 0.5 Gy/sec.로 0.5, 1, 1.5, 2, 3, 5, 7 Gy로 조사후에는 증가현상을 보이고 있다. Acid phosphatase 활성도는 상기의 어떠한 선량에서도 나타나지 않고 있다. 잠재적으로 이러한 효소들은 방사선 피폭의 지표물질로 사용될 수 있으며 생화학적 지식과 기술을 이용한 좀더 나은 지표물질을 찾기 위하여 계속적인 조사가 필요하다. Enzyme activity changes in rat blood as biochemical indicator useful for evaluating exposure dose were experimentally studied. The experimental results obtained are as follows: 1) Alkaline phosphatase activities increased in the blood serum until 24 hours after 0.1, 0.25, 0.5, 2 and 4 Gy irradiation and its activities returned mormal condition after 72 hours of post-irradiation. Creatine kinase activities increased in the blood serum until 72 hours after 2 and 4 Gy irradiation but any significant activity changes were not detected after 0.1, 0.25 Gy irradiation. 2) Malate dehydrogenase activities did not reveal available changes changes after 0.1, 0.25, 0.5 Gy irradiation and lactate dehydrogenase activities decreased in the blood serum after 0.1, 0.25, 0.5 Gy irradiation. 3) Glutamate oxaloacetate transaminase activity changes were detected in the blood serum after 0.1, 0.25, 0.5, 2, 4 Gy(0.1 Gy/min.) and GOT activities increased after 0.5, 1, 1.5, 2, 3, 5, 7 Gy(0.5 Gy/sec.). Any acid phosphatase activities were detected in the blood serum after 0.1, 0.25, 0.5, 2, 4 Gy(0.1 Gy/min.) and 0.5, 1, 1.5, 2, 3, 5, 7 Gy(0.5 Gy/sec.) irradiation. Potentially some of these enzymes can be used as indicator protein for radiation injury. Futher investigation is needed to find better biochemical indicatiors utilizing recent knowledge and techniques of biochemistry.

特用資源植物의 硏究 : 한국임학회지에 게재된 논문을 중심으로 Based on the Articles Published in the Journal of Korean Forestry

이재선,김철우,배찬호,송재모,강효진,황석인,문흥규 江原大學校 森林科學硏究所 2003 Journal of Forest Science Vol.19 No.-

한국임학회지 (1962년의 1호~2002년의 91권 6호)에 게재된 특용자원식물 관련 논문에서 식·음용식물, 약용식물, 사료식물, 조경식물, 섬유식물, 산업용식물 및 밀원식물로 분류하고 그 내용에 따라 입지환경, 생태, 생리, 번식, 조림(또는 무육, 재배), 유전·육종, 분류(또는 식별), 병·충해와 방제, 동물피해와 방제, 성분분석, 식생정보, 생물공학, 경영·경제 및 총설로 나누었다. 총 1,434편의 발표 논문 중 유용식물자원을 대상으로 한 논문은 27.6%를 차지하는 396편이었고, 내용은 식생정보 60편(15.2%), 생리 56편(14.1%), 유전·육종 56편(14.1%), 번식 53편(13.4%) 및 생태 37편(9.3%)이었다. 조림(무육·재배)은 11편(2.8%)으로 특용자원식물의 규모경영이 이루어지지 않고 있음을 시사하고 있으며, 이것은 경영·경제 분야가 6편(1.5%)인 것과 맥을 같이 하고 있었다. 연구대상 식물은 잣나무(42편), 아까시나무(23편), 밤나무(14편) 및 은행나무(14편) 순으로 높았고, 이 식물들과 관련한 연구내용은 번식, 생리, 유전·육종, 생태 및 병·충해 순이었다. 연구의 목적, 내용, 결과 및 대상식물 등을 고려하여 보면, 1) 초본식물에 대한 보다 많은 연구, 2) 타산업 또는 학분 분야와의 공동연구, 3) 자원 보전적 연구 및 4) 연구주체자 간의 연구결과의 공유 등이 매우 요망된다. The articles, published in the Journal of Korean Forestry from Number 1(1962) to number 6, Volume 91(2002), were surveyed and investigated for the research trend analysis about resource-plants for special use or purpose, i.e edible plants, medicinal plants, feed resource, landscape plants, fiber plants, industrial usage, and bee plants. If the purpose or subject matter of the research was construction or furniture timber production, mushrooms and/or pulp and Paper, such research was not included in this study. These articles were classified again depending on the content of research into 14 categories : habitat environment, ecology, physiology, propagation, silviculture(tending and culture), genetics and breeding, identification, insect and disease control, animal-related research, cemponent analysis, vegetation survey, biotechnology, management, and review. Among the total 1,434 articles published, 396 ones (27,6%) were related with plants for special use or purpose. Vegetation survey was 60(15.2%) ; physiology 56(04.1%) ; genetics and breeding 56(14.1%) ; propagation 53(13.4%) ; and ecology 37(9.3%). Siviculture research field included 11 articles (2.8%), which indicates that the management of resource-plants is to far from economic income as seen in the low number of management research filed articles, i. e., only 6 reports(1.5%). Korean white Pine was most popular for research and included 42 articles ; Robinia pseudoacacia 23 Castanea crenata 14 : and ginkgo tree 14, Research related with these species had focused mainly or propagation, physiotogy, genetics and breeding, ecology and pest control. Based on this survey and analysis, the followings are suggested : 1. More research is required on forest herbaceous plants. 2. Cooperative research work with other industrial and/or scientific area is recommendable for commercialization including medicine, cosmetics, and food etc. 3. Research resource-plant conservation. which includes biology, social education and policy, should be supported for next generation. 4. Mutual correspondence and information exchange about the research results between researchers and institutes is more necessary than now.

Inhibitory Effect of Clavicepitaceae on Serotonin Release out of Human Platelets and Human Platelet Aggregation

박화진,--,--,--,--,--,-- THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 2004 Journal of biomedical laboratory sciences Vol.10 No.1

We have investigated the effects of hypha-water extracts (HWE), fruit body-water extracts (FWE) and cordycepin from Cordyceps militaris on serotonin release out of human platelets and human platelet aggregation. HWE and FWE inhibited the release of [^(3)H]-serotonin from human platelet stimulated by thrombin (2 U/ml) or collagen (20 ㎍/ml) in a dose-dependent manner. Furthermore, cordycepin, a major component of Cordyceps militaris, inhibited the human platelet aggregation induced by collagen (10 ㎍/ml) in a dose-dependent manner. These results suggest that cordycepin containing in HWE and FWE may inhibit the serotonin release by suppressing the collagen-induced human platelet aggregation. Accordingly, our data demonstrate that HWE and FWE containing much cordycepin might have antithrombotic and antimigrainous functions.

Inhibitory Effect of Cordycepin on Human Platelet Aggregation

박화진,--,--,--,--,--,-- THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 2004 Journal of biomedical laboratory sciences Vol.10 No.1

Cordycepin separated from Cordyceps militaris is a major physiologic active component in Cordyceps militaris. The platelet aggregation is stimulated by Ca^(2+), which is either mobilized from intracellular endoplasmic reticulum or transported from extracellular space. cGMP antagonizes the actions of Ca^(2+). Based on these facts, we have investigated the effects of cordycepin on the mobilization of Ca^(2+) and the production of cGMP on collagen (10 ㎍/ml)-induced human platelet aggregation. Cordycepin potently stimulated the human platelet aggregation induced by collagen (10 ㎍/ml) in a dose-dependent manner. Cordycepin (500 μM) inhibited also the collagen-induced human platelet aggregation in the presence both 1 mM and 2 mM of CaCl_(2). These are in accord with the results that cordycepin inhibited the Ca^(2+)-influx on collagen-induced human platelet aggregation. These results suggest that cordycepin decrease the intracellular Ca^(2+) concentration to inhibit collagen-induced human platelet aggregation. Besides, cordycepin increased the level of cGMP on collagen-induced human platelet aggregation. This result is related with the decrease of intracellular Ca^(2+) concentration, because cGMP inhibits the mobilization of Ca^(2+). In addition, cordycepin inhibited the human platelet aggregation induced by LY-83583, inhibitor of guanylate cyclase. This result suggested that cordycepin inhibit the platelet aggregation by stimulating the activity of guanylate cyclase. In conclusion, we demonstrated that cordycepin might have the antiplatelet function by inhibiting Ca^(2+)-mobilization via the stimulation of the production of cGMP.

Liquid crystal alignment properties of n-alkylsulphonylmethyl-substituted polyoxyethylenes

Kang, Hyo,Sohn, Eun-Ho,Kang, Daeseung,Lee, Jong-Chan Taylor Francis 2009 Liquid crystals Vol.36 No.8

<P> The liquid crystal (LC) alignment properties of LC cells fabricated with films of n-alkylsulphonylmethyl-substituted polyoxyethylenes (#S-PEO, # = 4, 6, 7, 8 and 10), where # is the number of carbon atoms in the n-alkyl side groups having different n-alkyl chain length, were investigated as a function of the rubbing density. The LC cells made from unrubbed #S-PEO (# ≥8) films having more than eight carbon atoms in the n-alkyl side groups showed homeotropic LC alignment. The homeotropic LC alignment behaviour correlated well with the surface energy values of the unrubbed #S-PEO films; homeotropic LC alignment was observed when the surface energy values of the unrubbed #S-PEO films were smaller than about 21.62 mJ m-2. The LC cells made from rubbed #S-PEO (# ≥7) films having more than seven carbon atoms with a rubbing density of 150 showed homeotropic LC alignment. It was also found that the tilt angle of the LCs on the rubbed #S-PEO films was affected not only by the n-alkyl chain length of the polymers, but also by the rubbing density, regardless of the surface energy value of the #S-PEO film.</P>