• Journal of the Korean Vacuum Society
• /
• v.15 no.2
• /
• pp.152-161
• /
• 2006

In order to test the capacity of Si(5 5 12) as a potential template for nanowire fabrication, Bi/Si(5 5 12) system has been studied by STM. With Bi deposition, Si(5 5 12) has been transformed to Si(3 3 7) terrace. Initially Bi atoms selectively replace Si-dimers and Si-adatoms with Bi-dimers and Bi-adatoms, respectively. With extended Bi adsorption, Bi-dimers adsorb on the pre-adsorbed Bi-dimers and Bi-atoms. These dimers in the second layer form Bi-dimer pairs having relatively stable $p^3$ bonding, Finally, the Bi-dimer adsorbs on the Bi-dimers in the second layer and saturates. It can be deduced that both surface transformation to (3 3 7) and site-selective Bi adsorption are possible due to substrate-strain relaxation through inserting Bi atoms into subsurface of Si substrate.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.04a
• /
• pp.77-77
• /
• 1999

담배용 필터에 사용되고 있는 재료는 아세테이트, 종이, 폴리프로펼렌, 부직포등이 주로 이용되고 있으 며 담배연기의 흡착능을 향상시키기 위한 방법으로 활성탄 제오라이트와 같은 흡착제를 담배필터에 첨가하여 사용하고 있다. 본 실험에서는 펼터에 가장 보편적으로 많이 사용하고 있는 활성탄을 종이 제조과정에 첨가하여 나타나는 물리적 특성을 관찰하였고 제조된 종이를 담배필터에 적용하기 위하여 현행 습식 크림핑(crimping)방법과는 달리 건식 크림핑(crimping)방법을 이용한 적합한 조건을 검토하 였으며 이에 따른 담배필터에서의 연기흡착능을 분석한 결과는 다음과 같다. 1. 시트의 물리적 특성과 담배 연기성분 홉착능을 예측하기 위하여 펄프의 불성과 uv 홉착능을 분 석한 결과 Sw-BKP가 Hw-BKP에 비하여 강도적 성질이 우수하였고 또한 메틸렌불루(methylene b blue) 흡착능도 높은 경 향을 나타내 었다. 2. 활성탄 함량의 증가에 따라 섬유간의 결합력이 약화됨에 따라서 시트의 인장강도 및 파열강도가 감 소하는 경향이 가장 크게 나타났으며 평량이 펼프 배합비보다 높은 인자로 작용하였다. 또한 인자 간의 교호작용에서는 평량과 활성탄 함량에 따라서 크게 나타났으며 평량, Sw-BKP의 함량이 증가할 수록 인장강도는 증가하였다. 3. Stiffness는 활성탄 함량 펄프 배합비 평량의 순에따라 중요한 인자로 작용하였고 활성탄 함량 이 많을수록 stiffness는 감소하였으며 평 량 Sw-BKP의 함량이 높을수록 증가하였다 인자간의 교 호작용은 평량과 활성탄 함량이 다른 요인에 비하여 높은 경향을 보였다. 4. 인열강도는 활성탄 함량이 증가함에 따라 가장 크게 감소하였고 시트의 평량이 펄프 배합비보다 높은 인자로 작용하였으며 평 량 Sw-BKP의 함량이 높을수록 증가하였다 인자간의 교호작용에서는 펄프 배합비와 활성탄 함량에 따라 크게 나타났다. 5. 종이 필터지에서 시트의 평량이 bulk에 가장 큰 인자로 작용하였는데 이는 같은 두께에서 평량올 변화시킨 요인으로 판단되며 시트의 평량이 높을수록 감소하였고 활성탄 함량, Sw-BKP의 배합비 가 높을수록 증가하였다. 또한, 인자간의 교호작용은 평 량과 활성 탄 함량에 따라 크게 작용하였다. 6 6. Crimp index는 관능검사 결과로서 활성탄 함량이 증가함에 따라 현저하게 저하되었으며 평량 및 S Sw-BKP의 배합비가 높을수록 양호한 결과를 나타내었다. 인자간의 교호작용에서는 평량과 펄프 배합비에 따라 가장 높은 경향을 나타내었다. 7 활성탄을 첨가하여 제조한 종이필터의 담배 연기성분 흡착능은 acetate tow에 charcoal을 첨가한 필터에 비하여 tar흡착능이 6% 이상 향상되었고, 특히 증기상 물질(vapour phase)중 aldehyde류에 대한 제거율(removal efficiency)이 높게 나타났다. 8. 건식 크림핑 방법에 의한 담배필터 제조시 펼프의 홉착능, 시트의 강도적 특성, 크림핑 조건 및 담 배 연기성분 흡착능 등을 고려하여 적정조건을 선정하였으며, 펄프 배합비(Sw-BKP따w-BKP)는 6 65/35, 시트의 평량은 40g/$m^2$ 활성탄 함량은 10% 이었다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.6
• /
• pp.263-268
• /
• 2005

The ceramic balls impregnated with $20{\sim}40nm$ sized Ag colloid were examined for heavy metals absorption and antibacterial activities in the drinking water. The preparation conditions of ceramic ball that the porosity was excellent were as follows: starting material: 85 wt% $Ca_{10}(PO_4)_6(OH)_2$, binder: 5 wt% PVA and 15 wt% ${\alpha}-Ca_3(PO_4)_2$, heating temperature: $1000^{\circ}C$, duration: 3 hrs. The ceramic balls obtained under these conditions showed specific surface area of $110m^2/g$, pore size of $120{\mu}m$ and porosity of 80%. Also, as the results of a performance test on a rate of adsorbing and removing heavy metals in the drinking water by using the.AAS, heavy metals such as Zn, Mn, Fe and Cu were removed to the extent that their content became 0.03mg/l or lower after 1 day and they showed an excellent bactericidal activity that all coliforms were killed after 3 hrs.

• Analytical Science and Technology
• /
• v.10 no.6
• /
• pp.408-417
• /
• 1997

Normal phase or reversed phase liquid chromatographic separation of some structural isomers of functionalized heterocyclic compounds has been carried out by using several different columns and various mobile phases. The optimal experimental conditions for separation of structural isomers were found on a ternary solvent system including alcohol as a modifier. This polar modifier is preferentially adsorbed onto strong adsorption site, leaving a more uniform population of weaker site that then serve to retain the sample. This 'deactivation' of the adsorbent leads to a number of improvements in subsequent separations. The optimal mobile phase system of separation were found on normal phase on structural isomers. Retention mechanism of normal phase system was also studied depending on adsorption strength between solute and stationary phase of column. However, retention factors of reversed phase system were found on hydrophobic interaction with solvophobic effect.

• The Korean Journal of Pesticide Science
• /
• v.8 no.3
• /
• pp.175-183
• /
• 2004

The characteristics of the experimental compound EK-5439 [3-Chloro-2-[4-chloro-2-fluoro-5-(5-methyl-3-phenyl-4,5-dihydroisoxazol-5-yl-methoxy)-phenyl]-4,5,6,7-tetrahydro-2H-indazole] was investigated to characterize as a new herbicide to use in rice field. The selectivity between rice and barnyardgrass was very good when treated from 0 to 4 days after seeding under soil application. In the overflowing experiment, herbicidal efficacy of EK-5439 was stabilized 12 hrs after application. Vertical migrations in submerged paddy soil of EK-5439 and oxadiazon were equally observed below a soil depth of 1 cm under 5 cm/day leaching condition. Half-lives for herbicidal efficacy of EK-5439 and oxadiazon were 6.1, and 9.6 days, respectively, under submerged paddy condition. EK-5439 showed rapid adsorption to the soil clay, such as bentonite.

• Korean Chemical Engineering Research
• /
• v.53 no.3
• /
• pp.401-406
• /
• 2015

Getter is a class of materials used in absorbing gases such as hydrogen and moisture in microelectronics or semiconductor devices to operate properly. In this study, we developed a new device structure consisting of porous anodized alumina films on textured silicon wafer, which have cost efficiency in materials and processing aspects. Anodic aluminum oxide (AAO) with controlled pore sizes can be applied to a high-efficiency moisture absorber due to the high surface area and OH- saturated surface property. The moisture sorption capacity was 2.02% (RH=35%), obtained by analyzing isothermal adsorption/desorption curve.

• The Journal of Natural Sciences
• /
• v.6 no.1
• /
• pp.103-108
• /
• 1993

Zeolites were discovered as a natural mineral more than two hundred ago. In the beginning, the mineral was used as ion-exchange material and adsorbent. After the end of World War II , however, a variety of zeolites have become available in large amounts because of the establishment of low temperature synthesis and the discobery of natural zeolite deposits of sedimentary origin. Various uses of xeolite were developed utilizing the unique crystal strucrure and function of these minerals. In connection with this development remakable progress has also been made in basic stuides on the related geology and mineralogy, crystallization from sols and gels, structure, ion exchange, adsorption and cataiysis. As a result, zeolites, which had been known only as mineral specimens displayed in museums. established a firm position among the high-technology masterials with excellent functional capabilities.

• Applied Chemistry for Engineering
• /
• v.7 no.2
• /
• pp.299-307
• /
• 1996

The surface tension of PO added sodium poly(oxyethylene(EO), oxyisopropylene(PO)) dodecyl ether sulfate firstly were slightly lower than EO added sulfate in the concentration range of $10^{-6}{\sim}10^{-3}mol/{\ell}$. And they had lower critical micelle concentration ($10^{-4}{\sim}9{\times}10^{-5}mol/{\ell}$) than general anionic surfactants. The adsorptivity ($2.2{\times}10^{-10}mol/cm^2$) of sodium $(PO)_{10}(EO)_5$ dodecyl ether(compound of PO addition firstly) calculated by Gibbs' adsorption isotherm were higher than that of sodium $(EO)_{10}(PO)_5$, dodecyl ether(compound of EO addition firstly), but were lower than that of sodium dodecyl sulfate (${\Gamma}=3.2{\times}10^{-10}mol/cm^2$). These could be understood that the adsorption areas of compounds were very large because of their high molecular weight. Moreover, PO compounds showed better properties than EO compounds in foamability, emulsifying power for organics (n-hexane, benzene), detergency for the lard, tallow oil mixture and dispersability for iron oxide. It was interpreted in terms of surface properties of the PO compounds. These showed that the interfacial activity become higher when hydrophilic and hydrophobic portion existed in aggoromerated state respectively. The test results of emulsifying power for organics (n-hexane, benzene) showed better for benzene than n-hexane. Eight kinds of sodium (EO, PO) dodecyl ether derivatives showed irregular dispersibilities for polar iron oxide in water dispersed media.

• Korean Journal of Food Science and Technology
• /
• v.22 no.4
• /
• pp.456-460
• /
• 1990

The processing conditions for the production of meat snack were investigated by using a Bonnot Single-screw extruder Pork and thicken meat were mixed with corn flour in various ratios, respectively, and extruded at different screw speeds(120-260 rpm). As the meat content was increased, the expansion ratio, water absortion index, lightness and yellowness of the extrudate were decreased. The expansion ratio tended to increase with an increase in screw speed, but the opposite relationship was observed with the maximum meat content(meat corn flour=2:1). The maximum water absorption ratio was obtained at the screw speed of 190rpm when the meat content was relatively low, but it moved to 120 rpm as the meat content was increased. The bulk density of the extrudate was significantly increased as the meat content exceeded 50% and no significant differences in bulk density was found at the highter meat content. The redness increased as the moisture content was increased. The maximum breaking strength was attained at the meat-corn flour ratio 1 : 1, and the breaking strength tended to decreased as the screw speed increased.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.4
• /
• pp.230-235
• /
• 1993

This study was carried out to investigate the supplying capacity of various forms(Water soluble, exchangeable, and available) of potassium in soils of different site quality by using surface soils from the Japanese cedar(Cryptomeria japonica) forests in Cheju island. Major results can be summerized as follows. Using continuous leaching methods with 0.01N-HCl, accumulated amounts of available potassium from surface soils of site upper and site low were about 0.6me/100g and 0.4me/100g, respectively. The release ratio of available potassium in the first $1{\ell}$ leaching of 0.01N-HCl to the total available potassium leached with $6{\ell}$ of 0.01N-HCl was over 80% for both sites, and this suggester that surface soil of both sites had the weak potassium adsorptivity as the typical volcanic ash soil. The ratio of the exchangeable potassium to the water soluble potassium was 1 : 1 for both sites. The ratio of the exchangeable potassium to the available potassium was 1 : 1 for the site low but the smaller ratio value for the site upper, indicating that the potassium supplying power of the site upper was greater than that of the site low. Available potassium was highly correlated with exchangeable Ca($0.83^{**}$) and Mg($0.84^{**}$).