靑銅合金의 機械的 性質에 關한 硏究

許在根 서울産業大學校 1980 논문집 Vol.13 No.1

Recently, many active research On the mechanical behavior Consed by the Vibration have been Carried Out the Cu-Sn alloy, and it is Very Seldom the dlata of bell with Cu- Sn alloy. In this Paper the author's Concern has been Concentrated On the mechanical Properties, the results Obtained in this Study are summerised as follows. 1. Tensile Strength of A (Cu80%, Sn20%) is 20.1kg/㎟,and tensile Strength of B(cu85%, Sn15%) is 21.5kg/㎟,therefore the Strength of B is higher about 7% than A. 2. Hardness of A is higher about 22% than B. 3. The absorbed energy of A and B are Similarly on impact test. 4. The α Solid Solution A and B are Changed δ Phase, and brittleness ofδ Phase on A are appeared higher than B.

Lath Martensite의 組織構成

許在根 서울産業大學校 1984 논문집 Vol.20 No.1

Structural characteristics of lath martensite were investigated indetail using Fe-C alloys plain carbon steels with carbon of up to 0.8%,18% Ni maraging steel and Fe-0.2%C alloys with an addition of about 1% of Mn Si, Cr, or M. The construction of lath martensite structure changes with carbon content. The packet regions are clearly formed within a prior austenite grain at lower carbon content. but they are not observed in the range of 0.5-0.8%C. The block regions within a packet are observed only in the steels below about 0.3%C. Structure of lath martensite in the 18% Ni maraging steel is characterized by the block region which are well-developed and completely partitions a packet region. where the blocks in the low carbon steels are not well-developed regions. A packet size gradually decreases with increase in carbon in carbon conternt up to 0 .4%C and repidly decreases in the 0.6 and 0.8%c. A linear relation exists between the austenite grain size and packet size in Fe-0.2%C alloy and 18 Ni maraging steel. the increase in block with of maraging steel with increasing austenite grain size is very small. Alloying elements within about 1% have little effect on the construction of Lath martensite and the packet size

스테인레스鋼纖維로 康化된 알루미늄과 알루미늄合金複合材의 界面反應에 對한 硏究

許在根 서울産業大學校 1986 논문집 Vol.24 No.1

This study is based on the reaction of the interface between stainless steel fiber and aluminum to which specific elements were added. In this investigation aluminum and aluminum alloy which had been reinforced which stainless steel fiber was made by the method of liquid infiltration. The components that had been formed between them were confirmed by X-ray and EPMA, also the thickness of each layer was measured by a optical microscope. As the influence of te specific elements when the composite material was made, cobalt was added to the interface. On the other hand the other elements didn't add themselves to interface, but added Cr., Ni to interface. In microscopic examination the thickness each interface didn't change and the diameter of the fiber became shorter. Most of the composite material had been higher strength than theoretical one, which establishes face that the interface cohesion is good when the composite meterials are made. In the hardness test of the composite material we could find that their interface is harder than the fiber or the matrix is, which establishes that the intermetallic compound can be formed by the sufficient reaction of the fiber and the matrix.

高Mn鋼에서 各種元素添加와 炭化物析出에 對한 硏究

許在根 서울産業大學校 1983 논문집 Vol.19 No.1

Some Hadfield Steels with 1%Si 2% Al 0.8% Mo 4% Cr were studied mainly by micrography on isothermal carbide Precipitation after Solution treatment. Isothermal Precipitation diagrams for all steels were determined as c-carve fundamentally similar to that of standard Hadfield steel. By addition of 1%Si, the carbide Precipitation in steel was little affected, But the temperature range in which pearlitic constituent(PC) appeared was slightly extended. By addition of 2% Al, the grain boundary carbide precipitation in high temperature rang was accelerated, but the tramstormation in ti PC was retarded and its temperature range was limited in a Slightly narrow range. Moreover, matrix precipitation of carbide in high temperature range was disturbed remarkably by addition of Al. By addition of carbide forming elements such as Mo and Cr the precipitation of carbide was accelerated especially in high temperature range, and the precipitation temperature range was extended to higher temperature.

鍍金에서 Iron-Nickel 二元合金의 電着에 關한 硏究

許在根 서울産業大學校 1981 논문집 Vol.15 No.1

In the Fe-Ni alloy plating, Fe and Ni are dissolved in the plating Solution. In the plating solution ferrous iron tend to ferric iron in the atmosphere or plating process. In the case of the ferric iron, it is very difficult to acquire good plating surface because that ferric iron not only precipitate in the plating solution but makes rough sulface. Therefore, in this procedure, Reducing from ferric iron to ferrous iron for the preventing ferrous iron deposit by adding Reducing agents and stabilizers. This study has done by using the Reducing agents associated with the effect on the precipitation and plating conditions. 1. The most suitable reducing agents was tartaric Acid and citric Acid. 2. composition of the associated with increasing temperature was decreased amount of iron and little effected. 3. In the case of adding reducing agents was decreased the amount of iron in the dectrodeosite than not adding. 4. Amount of deposit with very of pH tend to a little decreased at low pH but high pH Precipitated to scarcely similar state.

冷間壓延法에 依한 Aluminum Clad鋼의 接着機構에 關한 硏究

許在根 서울産業大學校 1985 논문집 Vol.22 No.1

A number of studies on bonding mechanism of clad metals by cold rolling have been reported, but a definite conclusion of the bonding mechanism has not yet been recognized. In cold clad practice, it can be thought that the factors affecting the bondability may be kind of metals, surface condition, thickness ratio of metals, temperature, relative ship, and so on. Several factors affecting the bond shear strengh of aluminium clad steel by cold rolling were examined. Furthere, the temperature of the bond during rolling was measured by I.C. thermo-couple. As the result, an average temperature of about 650℃ in 0.05 sec. was obtained. From these facts it may be suggested that the bonding mechanism by cold rolling is mutual fusion of metals at contact part under high pressure and high deformation by frictional heat caused by relative ship of metals.

高張力鋼 熔接部에 대한 機械的 性質에 關한 硏究

許在根 서울産業大學校 1982 논문집 Vol.17 No.1

Recently high Strength Steel has been produced in Korea, This study aims aat a research on the mechanical characteristic and microscopic structure of the weld zone of the high strength steel when welding it by means of a lowhydrogen-type welding rod. Some of the signiticant findings are:tensile strength in weld zone by 10kg/㎟ more than basemetal:L-260(60㎏/㎟ type welding rod) was Superior to L-200(50㎏/㎟ type welding rod) in terms of its strength: hardness value increased more in weld zone than in basemetals in particular hardness value in heat effected zone was the highest: impact value increased in weld zone about 2 or 3㎏-m more than in base metal: the microscopic structure of weld zone was finer than that of base metal. On the basis of thesefacts, this study concluded: the weld Zone of the high strength steel produced in korea increased in its tencile strength, yield strength, hardness Value, and impact value than base metal: the microsopic structure of the weld zone of the high strength steel is finer than that of base metal. Therefore, in case of using the high strength steel for making a structure three important factors should be attended to in its constrution: first the choise of a welding rod: Second the size of weld zone (X and Y direction) third, the structure of weld zone.

Escitalopram-Induced Amenorrhea and False Positive Urine Pregnancy Test

Vithyalakshmi Selvaraj,Siv Hour,Palanikumar Gunasekar,Caron Gray,James F. Smith 대한가정의학회 2017 Korean Journal of Family Medicine Vol.38 No.1

Escitalopram is a selective serotonin reuptake inhibitor antidepressant approved by the Food and Drug Adminis-tration for the treatment of major depressive disorder and generalized anxiety disorder. A 34-year-old female pa-tient with major depressive disorder developed amenorrhea and had a false-positive urine pregnancy test after ini-tiation of escitalopram treatment. To our knowledge, no published case report of amenorrhea and false-positive urine pregnancy tests in women taking escitalopram exists. This case report suggests that women of child-bearingage should be carefully monitored for amenorrhea while they are on an antidepressant treatment regimen.

Protect User’s Privacy in Location-based Service Queries

Jia-Ning Luo,Ming-Hour Yang,Kuo-Yu Tsai 한국정보기술학회 2017 Proceedings of The International Workshop on Futur Vol.2017 No.7

Enzymatic Hydrolysis of Gelatin Layers of X-Ray Films and Release of Silver Particles Using Keratinolytic Serine Proteases from Purpureocillium Lilacinum LPS # 876

( Ivana A Cavello ),( Roque A Hours ),( Sebastian F Cavalitto ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.8

Enzymatic decomposition of gelatin layers on used X-ray films and repeated utilization of the enzyme for potential application in silver recovery were investigated using keratinolytic serine proteases from Purpureocillium lilacinum LPS # 876. At pH 9.0, the enzymatic reaction was enhanced by the increase of enzyme concentration or by the increase of the temperature up to 60oC. Under the conditions of 6.9 U/ml, 60oC, and pH 9.0, hydrolysis of the gelatin layers and the resulting release of silver particles were achieved within 6 min. The protective effect of polyols against thermal denaturation was investigated. The presence of glycerol and propylene glycol increased enzyme stability. When the reusability of the enzyme for gelatin hydrolysis was tested, it could be seen that it could be effectively reused for more cycles when glycerol was added, compared with the enzyme without protective agents. The results of these repeated treatments suggested that a continuous process of recycling silver from used X-ray is feasible. Keeping in mind that recycling is (at the present time) needed and imperative, it can be remarked that, in this research, three wastes were successfully used: hair waste in order to produce serine proteases; glycerol in order to enhance enzyme thermal stability; and used Xray films in order to recover silver and PET films.