• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.377-386
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• 1996

Austenitic stainless steel type 304L has been nitrided under the low pressure of high nitrogen environment for 5 hours by the square-wave-pulse-d.c. plasma as a function of temperature 400~$600^{\circ}C$ and of pulsation. At the temperature range lower than $500^{\circ}C$ and at the relatively high ratio of pulse duration to pulse period, nonstoichiometric stainless steel nitride has been developed in the form of a thin layer which has many cracks. At the temperature range higher than $500^{\circ}C$, with the increasing temperature or with the increasing ratio of the pulse duration to pulse period up to 50s/100s, the nitrided layer was composed mainly of CrN and Fe4N phases and became thick, uniform, columnar and nearly crack-free. The nitrided layer at $500^{\circ}C$ was mixed with the low-temperature layer and the high temperature layer and was very brittle.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.12
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• pp.1662-1671
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• 2007

The change in physical properties of polypropylene nonwoven fabrics used as top sheet for disposable sanitary goods was carried out using chitosan that is a type of natural polymer and has excellent human affinity by varying the molecular weight and concentration of chitosan. Low molecular weight(LMW) chitosan treated fabrics were found to be evenly coated on fabrics and had better dyeability by apparent dye uptake and its deodorization rate increased over the time. On the other hand, high molecular weight(HMW) chitosan treated fabrics showed higher add-on ratio and its dynamic water absorption rate and represented an increase in water transport rate. With chitosan treatment, its air permeability was improved. Regardless of the type of bacteria and chitosan concentration, its antibacterial activity was excellent in the case of the HMW chitosan treatment. In this regard, chitosan treatments by using a relatively high molecular weight was found as an effective way in the functional improvement of moisture properties and antibacterial activity including their most important performance in sanitary nonwoven fabrics.

• Journal of Sericultural and Entomological Science
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• v.47 no.1
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• pp.31-35
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• 2005

This study had done to find an easily-dyeing method for novices because the dyeing method of traditional indigo has not been general to the public so that only an expert could dye the fibers. The results are as the following. When the powders after burning the shell of cockle (tegillarca granosa) were added. pH of the solution was 12.35 The k/s value of 2.49 was the highest in the dye after dipping in the solution of indigo for 1-2 days and the k/s value was 3.10 when adding 20 g/l of the starch (55% corn-starchy products in Korean market) into the solution of indigo. In addtion, the k/s value was the highest when fermenting temperature was $30^{\circ}C$ and when the powders after burning the cockle shell were 4 g/l. There were no differences between water and lye of rice straw which had used for the ferment of indigo. The components of two dye which has traditionally made of the cockle shell and which has made of calcium hydroxide were all the same.

• Economic and Environmental Geology
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• v.40 no.2 s.183
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• pp.171-189
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• 2007

A study of anisotropy of magnetic susceptibility (AMS) was undertaken on Cretaceous granitic, volcanic and sedimentary rocks in the eastern region of the Yangsan fault, southeast Korea. A total of 542 independently oriented core samples collected form 77 sites were studied. The main magnetic mineral in granitic rocks is magnetite according to the magnitude of bulk susceptibility, high-temperature susceptibility variation and isothermal remanent magnetization. Both of magnetic lineation and foliation with NE-SW trends are revealed in the granitic rocks, while volcanic rocks show scattered directions and sedimentary rocks show only load foliation parallel to the bedding planes. The following evidences read to the conclusion that both magnetic fabrics in the granitic rocks have been obtained by a tectonic stress before full solidification of the magma: (i) A fully hardened granitic rocks would get hardly any fabric, (ii) Difference of the magnetic fabric trends with those of the geological structures in the granitic rocks themselves formed by brittle deformation after solidification (e.g. patterns of small-faults and joints), (iii) Kinking of biotite and undulose extinction in quartz observed under the polarizing microscope, (iv) Discordance of magnetic fabrics in the granitic rocks with those in the surrounding rocks. The NE-SW trend of the magnetic foliations suggests a NW-SE compressive stress of nearly contemporaneous with the emplacement of the granitic rocks. The compression should have caused a sinistral strike-slip movement of the Yangsan Fault considering the trend of the latter. As the age of the granitic rocks in the study area is reported to be around $60\sim70$ Ma, it is concluded that the Yangsan fault did the sinistral strike-slip movement during this time (L. Cretaceous Maastrichtian - Cenozoic Paleocene).