400 계열 스테인레스 스틸 분말을 사용한 ABS Sensor Ring 개발

임종국,양현수,김경환,곽창섭 한국산업안전학회 1998 한국안전학회지 Vol.13 No.3

ABS sensor ring has been manufactured by P/M method using 400 series ferrite stainless steel. The results are as following: It is supposedly sufficient to use for control computer due to good experimental results of magnetic characteristics. Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. Thus the decreasing production process has been obtained. As a result of hardness and tensile test, 400 series ferrite stainless steel shown a good endurance when it is combined to C/V joint, and has a good hardness properties endurable to sand and pebble impact.

급냉응고된 Al - 9.45wt%Fe - 4.45wt%Cr 합금의 고온 크립거동

임종국,김경환,김택수 한국산업안전학회 1999 한국안전학회지 Vol.14 No.1

급냉응고 강화된 Al-9.45wt%Fe-4.45wt%Cr 합금의 크��거동을 40∼115㎫ 응력범위와, 300∼441℃(0.53∼0.667m) 온도 범위에서 조사하였다. 이 계열의 합금은 비행기 및 자동차의 구조용재료 혹은 엔진용 부품에 많이 사용되고 있으며, 재료의 사용이 주로 고온에서 이루어지므로 안전성을 확보하기 위해서는 크림실험이 특히 중요하다. 이 합금의 크��실험 결과 웅력지수와 크�� 활성화에너지가 높았으며 실험 응력과 온도에 크게 좌우되었다. 크��응력이 조대화에 강하게 영향미치는 것으로 보이기 때문에 모든 크립시편의 분산입자의 조대화율은 등온 소둔시편 보다도 더 빠르게 나타났다. 분산상과 연결된 전위는 고응력, 저온의 크��시편에서 더욱 자주 관찰되었다. Power law creep에서의 크��변형 속도는 문턱응력과 전위분리기구를 포함하는 Sherby와 Ro¨sler/Arzt식으로 예견되는 것과 일치함을 발견하였다. 이 합금에서 분산상은 void 생성원으로 작용하였으며 소위 입계파괴인 입자내의 연성파괴의 원인이 되었다. 생성된 void는 성장하여 Al기지내의 분산상과 분리되고, 슬립에 의해 결정립계에 집적되어 결국 입계파괴가 일어났다. 그러므로 이들 분산상이 A1_(13)Fe₄, Al_(13)Cr₂ and A1₂O₃의 형성에 의해 파괴 기구의 중요한 역할을 함이 입증되었다. The creep behavior of a rapidly solidified and consolidated Al-9.45wt%Fe-4.45wt%Cr alloy were investigated in the stress range 40 to 115 ㎫ and temperature range 300(0.53Tm) to 441 ℃ (0.66Tm). It is of use to available aerospace and automobile industries for the improved performance of materials used at high temperature. Because Al alloys with improved creep resistance offer the potential for lower weight and reduced costs in aerospace and automobile components (e.g., structural members and engine parts) through the replacement of heavier and more costly materials, the safety in use at high temperature is good. The alloy is characterized by high stress exponents and activation energies for creep, which are greatly dependent on the stress and temperature. Because the creep stress is seen to cause a strongly significant enhancement of coarsening, the coarsening rate of the dispersed particles in all crept specimens is faster than that in isothermally annealed specimens. Dislocations connecting dispersoids are observed more cofrequently in crept specimens with higher stress and lower temperature. The creep strain rates in the power law creep regime were found to be predicted much better by the Sherby and Ro¨ler/Arzt equation with the inclusion of a threshold stress and dislocation detachment mechanism. The dispersoids in this alloy were acting a source of void nucleation that finally leaded to ductile fracture within the grain so called intergranular. Each void was initiated, grown and failed at the dispersoids in the aluminium matrix. Grain boundary accommodation of the slip produced, which result in initiation of the void and then final transgranular fracture. Therefore, it was confirmed that these dispersoids played an important role in the fracture mechanism by the formation of A1_(13)Fe₄, Al_(13)Cr₂ and A1₂O₃.

410L 스테인레스 강의 ABS 센서 링 제조를 위한 자기적 특성에 관한 연구

임종국,양현수,곽창섭 한국열처리공학회 1998 熱處理工學會誌 Vol.11 No.4

It is well known for 410L ferritic stainless steel powder to applicate a sensor ring in anti-lock brake system of automobile, several studies, because of its excellent magnetic properties. This study was carried out to investigate the magnetic properties such as the maximum magnetic induction, coercivity and maximum permeability of the materials with functions of sintering density, time and temperature, and concluded as follows: 1. Sintering under the circumstances of Ar gas and the temperature of 1250℃ for 60min. showed that nitrogen was increased, whereas carbon and oxygen decreased in quantities. 2. Both maximum magnetic induction value of 4700Gauss and permeability of 200 were obtained at the maximum sintering density of 6.89g/㎠. Here, the properties showed a linear increasement with increasing the sintering density. 3. Coercivity sharply decreased with incresing the sintering density and reached to 7.6Oe at the maximum sintering density of 6.89g/㎠.

Investigation of the Incorporation Efficiency of $\beta$-Carotene into Liposomes

Rhim, Chae-Hwan,Lee, Kyong-Eun,Yuk, Hyun-Gyun,Lee, Sang-Chun,Lee, Seung-Cheol The Korean Society of Food Science and Nutrition 2000 Preventive Nutrition and Food Science Vol.5 No.3

Chemical and photochemical precesses during food storage an preparation rapidly degrade $\beta$-carotene, the most active form of carotenoids. We investigated the possibility of liposomes as tool to preserve $\beta$-carotene. Liposomes with $\beta$-carotene were prepared as multilamellar vesicles by using soybean phosphatidylcholine, in terms of the ratio of $\beta$-carotene to phospholipid and pH. Incorporated efficiency was 99.7% at 1:0.05 of phospholipid : $\beta$-carotene and at pH 9.0. As the concentration of $\beta$-carotene increased, the incorporated efficiency increased progressively. pH did not affect the incorporation efficiency greatly.

Differences in Bird Communities Between Before and After Forest Fire in Tropical Dry Dipterocarp Forest of the Northeastern Cambodia

Rhim, Shin-Jae,Son, Seung Hun,Lee, Eun Jae,Lee, Woo-Shin,Pech, Bunnat,Kry, Masphal Korean Society of Forest Science 2009 한국산림과학회지 Vol.98 No.5

This study was conducted to clarify the characteristics of bird communities between before and after forest fire in tropical deciduous Dipterocarp forest of Mondulkiri protected forest of the northeastern Cambodia from January to April 2009. The DBH distribution of trees were different in each DBH class. Most of the trees (> 80%) were belong to < 30 cm DBH. After the forest fire, coverage of understory layers were dramatically decreased by the fire. Total 64 species of birds were recorded, and 64 and 46 species of birds were observed before and after the fire, respectively. Observed number of individuals of bee-eaters, treepies, kingfishers, lapwings, herons, junglefowl, peafowl, prinias and warblers were decreased after the fire. The decrease of those species would be related with the change of habitat condition, such as decrease of water amount and understory coverage. For the management and conservation of junglefowls, peafowls, prinias and warblers, understory vegetation should be maintained in Mondulkiri protected forest, northeastern Cambodia.

Cultivation Characteristics of Lentinula edodes Strains using Oak Tree Log and Sawdust Blocks in the Republic of Korea

Rhim Ryoo,Eun-Jin Wang,Yeongseon Jang,Youngae Park,Kang-Hyeon Ka 한국버섯학회 2017 버섯 Vol.21 No.2

For centuries, Lentinula edodes called “Pyogo” in Korea has been cultivated as a high-grade edible mushroom in Asia. This is known as medicinal mushroom for cold prevention in oriental medicine. In the world market, this mushroom of Lentinula edodes is introduced as representative edible and medicinal mushroom in Asia. As consumer interest increases, Asian Lentinula edodes market is also growing. There is a record that Korea has already been used as a gourmet food on the royal meal table for the king in the 15th century Joseon Dynasty. In Korea's famous oriental book, it is cooked with many traditional foods because of the pharmaceutical efficacy of this mushroom. For long time ago, difference in cultivation as well as in mushroom growth of Lentinula edodes has studied in Korea. Recent advances in cultivation of selected high quality mushroom studied from substrate optimization using log and sawdust of oak tree. Cultivation of Lentinula edodes strain research controlled the production of large quantity of various substrate conditions. This mushroom mycelia and fruit-body were cultivated in log of oak tree and sawdust substrate cultivation in types of bioreactors. According to compared cultivation method, it presented the optimistic condition for the amount production of various Lentinula edodes strain in Korea.

TRANSGENIC CITRUS PLANT EXPRESSING δ-ENDOTOXIN GENE FROM B.T.TENEBRIONIS AND ISOLATION OF A NEWSTRAIN OF BACILLUS THURINGIENSIS

Rhim, Seong-Lyul,Kim, Won-Shik,Hwang, Li-Chun Plant Molecular Biology & Biotechnology Research C 1994 Plant molecular biology and biotechnology research Vol.1994 No.

A modified crystal δ-endotoxin gene of Bacillus thuringiensis subsp. tenebrionis producing a coleopteran insect-specific toxin was utilized to construct a chimeric gene capable of expressing in plant cells. Using an Agrobacterium tumefaciens binary vector system, the chimeric toxin gene was transferred into citrus leaf disks and recombinant plants were regenerated. Hybridization experiments demonstrated that these plants had the modified toxingene and expressed the insect control toxin protein gene. It is under study whether such expression in the citrus plants can type of Bacillus thuringiensis from soil. From a series of biochemical analysis, we assume that the strain isolated may be included in a new type of the Bacillus thuringiensis subsp. tenebrionis.

Imaging of Steel Bars Embedded inside Mortar Specimens for Nondestructive Testing

Rhim, Hong-Chul,Park, Kyung-Hyun Korea Concrete Institute 2000 KCI concrete journal Vol.12 No.1

Ground Penetrating Radar (GPR) with 1 GHz antenna has been used to locate a steel bar embedded inside laboratory-prepared mortar specimens. Four mortar specimens are made with the dimensions of 100 cm (length) x 100 cm (width) x 14 cm (depth). One specimen had no bars and the other three specimens had a Dl9 steel bar at 4, 6. and 8 cm depth. As a part of the experimental work, the dielectric constants of mortar specimens are measured during curing. As the curing time increased. the dielectric constant decreased with decreasing moisture content inside the specimen. The steel bar embedded inside mortar specimens has been successfully identified in all three cases. The results using signal processing scheme developed in this study significantly improved the output of a commercially available radar system.

Aging Effect of Poly(vinyl alcohol) Membranes Crosslinked with Poly(acrylic acid-co-maleic acid)

Rhim Ji Won,Hwang Ho Sang,Kim Dae Sik,Park Ho Bum,Lee Chang Hyun,Lee Young Moo,Moon Go Young,Nam Sang Yong The Polymer Society of Korea 2005 Macromolecular Research Vol.13 No.2

Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(acrylic acid-co-maleic acid) (PAM) were prepared to investigate the effect of aging on their morphology by swelling them for up to 7 days. PAM was used both as a crosslinking agent and as a donor of the hydrophilic-COOH group. A $30 wt\%$ weight loss of the dry membrane was observed in the swelling test after 6 days. The surface of the membrane was dramatically changed after the swelling test. The surface roughness of the PVA/PAM membrane was increased, as determined by atomic force microscopy (AFM). The swelling loosened the polymer structure, due to the release of the unreacted polymer and the decomposition of the ester bond, thereby resulting in an increase in the free volume capable of containing water molecules. The water molecules present in the form of free water were determined by differential scanning calorimetry (DSC). The fraction of free water increased with increasing swelling time. The swelling of the membrane may provide space for the transport of protons and increase the mobility of the protonic charge carriers. The proton conductivity of the membranes measured at T= 30 and $50^{\circ}C$ was in the range of $10^{-3} to 10^{-2} S/cm$, and slightly increased with increasing swelling time and temperature.

Transformation of Citrus with Coleopteran Specific $\delta$-Endotoxin Gene from Bacillus thuringiensis ssp. tenebrionis

Rhim, Seong Lyul,Kim, Il Gi,Jin, Tae Eun,Lee, Jin Hyoung,Kuo, Ching I,Suh, Suk Chul,Huang, Li Chun The Korean Society of Plant Biotechnology 2004 Plant molecular biology and biotechnology research Vol.6 No.1

A modified $\delta$-endotoxin gene of Bacillus thuringiensis ssp. tenebrionis (B.t.t.), encoding a coleoptera-specific toxin, was utilized to transform citrus plants, Citrus reticulata Blanco 'Ponkan' mandarian. By co-culturing the nucelli with Agrobacterium tumefaciens harboring the modified gene in the binary vector pBinAR-Btt, the chimeric toxin gene was transferred into citrus plants. The transgenic plants were selected on modified Murashige and Skoog medium containing kanamycin. Hybridization experiments demonstrated that the transgenic plants contained and expressed the toxin protein gene.