• Bulletin of the Korean Chemical Society
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• 제29권3호
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• pp.620-622
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• 2008

A new thiacalix[4]arene diamide (TCAm) has been prepared and its electrochemical property and complexation behavior toward various metal ions have been investigated by voltammetry. p-tert-Butylthiacalix[4]arene diamide (TCAm) exhibited selectivity toward Sr2+ ion over alkali, alkaline earth and transition metal ions while conventional calix[4]arene diamides showed selective binding property with Ca2+ ion. This is probably due to the bigger size of thiacalix[4]arene than those of calix[4]arene.

• 미생물학회지
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• 제18권3호
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• pp.133-147
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• 1980

Washed mycelia of Aspergillus nidulans FGSC159 were incubated in CMC minimal liquid medium and the culture filtrate which contained induced extracellular cellulase was fractionated by a three-step procedure including chromatography on Bio-Gel P-150, chromatography on DEAE-Sephadex A-50 and chromatography on Sephadex G-100. Three CMCase components ; F-I-Ia, F-I-Ib and F-II-Ia were prepared. No enzyme activity toward avicel could be detected in these components. Similarly, there was no ${\beta}-glucosidase$ activity. pH-optima of the three components were all 5.0 in acetate buffer. Temperature-optima for the activities of F-I-Ia, F-Ib and F-II-Ia were $45^{\circ}C,\;40^{\circ}C\;and\;50^{\circ}C$, respectively. F-II-Ia was shown to be more thermostable than the other two components. F-II-Ia was proved to have quite a different substrate specificity and action property and action property from those of F-I-Ia and F-I-Ib by product analysis on liquid chromatography.

• KSBB Journal
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• 제10권4호
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• pp.386-392
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• 1995

The high viscous ${\gamma}$-polyglutamic acid(${\gamma}$-PGA) from alkalophilic Alcaligenes sp. was purified and its solution property was investigated. The intrinsic viscosities for Na+ form and H+ form of ${\gamma}$-PGA were 31.1 and 0.38d$\ell$/g, respectively. The viscosity of H+-PGA was not influenced by pH or salts while that of Na+-PGA was influenced. The intrinsic viscosity of Na+-PGA solution decreased remarkably at the alkaline or acidic pH and showed the sharp decrease when salts were added. ${\gamma}$-PGA exhibited the property of the polyelectrolyte showing the .sharp decrease of intrinsic viscosity by the addition of NaCl, and intrinsic viscosity of dilute solution with the low concentration of NaCl was exponentially dependent on temperature and its temperature dependency increased with increasing NaCl concentration. The chain stiffness, coil overlap parameter and critical concentration of Na+-PGA were 0.08, 5.25 and 0.07g/d$\ell$, respectively.

• 한국항해학회지
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• 제18권4호
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• pp.59-81
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• 1994

Korean property and liability insurance companies have underwrited hull insurance without proper undrewriting ability. But after April 1996. in case of Korean insurance market being opened the companies have to make hull insurance rate by themselves. Accordingly, in this study, the writer embodies important factors in making hull insurance rate by an empirical survey. In empirical survey, the writer used a questionnaire, 74 proper data was obtained from 96 officers working in making hull insurance rate in 12 Korean property and liablity insurance companies and 24 the foreign companies at home. Reliability was tested by Cronbach's Alpha and a conceptual validity by Factor Analysis. Hypothesis estabilished in this study was tested by Correlation and Multiple Regression Analysis. Results of testing hypothesis are as follows: Firstly, the traits of insurer and the assured influence significantly(P<0.05) on making hull insurance rate. Secondly, expected loss ratio, ship manager, ship's age, insured amount, level of the cost of repairing and salvage, shipowner, period of insurance, level of overseas rating, profit and expense, trading limits, ship's classification, conditions of insurance, and ship's size influence significantly(P<0.05) on making hull insurance rate.

• 대한수학회지
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• 제61권5호
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• pp.953-973
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• 2024

Let R = ⊕_α∈Γ R_α be a commutative ring graded by an arbitrary torsionless monoid Γ. A homogeneous prime ideal P of R is said to be strongly homogeneous prime if aP and bR are comparable for any homogeneous elements a, b of R. We will say that R is a graded pseudo-valuation ring (gr-PVR for short) if every homogeneous prime ideal of R is strongly homogeneous prime. In this paper, we introduce and study the graded version of the pseudo-valuation rings which is a generalization of the gr-pseudo-valuation domains in the context of arbitrary Γ-graded rings (with zero-divisors). We then study the possible transfer of this property to the graded trivial ring extension and the graded amalgamation. Our goal is to provide examples of new classes of Γ-graded rings that satisfy the above mentioned property.

• 한국식생활문화학회지
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• 제3권2호
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• pp.163-175
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• 1988

본 조사는 서울시, 충남 대전시, 경북 영주시, 충남 서천군에 거주하는 530명의 주부를 대상으로 1987. 11. $16{\sim}11$. 28 사이에 떡의 이용실태와 시판제품의 품질특성에 대한 주부들의 평가도를 조사했던 바 여기에서 얻어진 결과를 요약하면 다음과 같다. (1) 조사대상자의 가정에서 이용하는 떡의 종류는 총 37종 이었고 그중 인절미(67.9%), 송편(66.6%), 흰떡 (51.4%), 개피떡(43.4%) 등 일부 도병류의 이용율이 높았고 전병류, 단자류 및 일부 증병류의 이용율은 아주 낮았다. (2) 의례시 떡의 이용율은 혼례때 가장 높았고 상례때 가장 낮았으며 돐, 혼례, 회갑때는 백일, 어른과 아이의 생일, 제사, 상례때보다 떡의 이용율이 높은 경향이었다. (3) 의례시 가장 많이 이용하는 떡은 백일, 돐, 아이의 생일에는 백설기로 어른의 생일, 혼례, 제사, 회갑에는 인절미로 나타났다. (4) 어른과 아이의 생일에는 케이크의 이용율이 (36%내외) 떡보다 높은 경향이었다. (5) 절식시 떡의 이용율은 설날에 가장 높았고 그 다음이 추석으로 나타났으며 그밖의 절식은 조사대상자의 가정에서 거의 지켜지지 않고 있었다. (6) 전체조사대상주부들중 61.7%가 앞으로도 계속 가정에서 떡을 만들겠다고 응답했던 바 아직까지 대부분의 주부들은 의뢰 또는 구입하기보다는 가정에서 직접 만들고 싶어하는 경향임을 알 수 있었다. (7) 조사대상주부들이 시판제품을 구입하는 이유는 간편해서가(65.8%) 가장 많았고 또한 시판제품을 구입하지 않는 이유는 내 손으로 직접 만들고 싶어서가(44.3%) 가장 많았던 바 두가지 이유가 상반되는 경향이었다. (8) 조사대상주부들은 시판되는 떡의 품질특성중 맛과 색 등 관능적인 면은 비교적 좋게 평가하는 경향이었고 가격, 위생성, 포장 및 저장성 등을 나쁘게 평가하는 경향이었다. 시판제품의 색은 주부의 거주지에 따라 농어촌에 거주하는 주부가 도시에 거주하는 주부보다 더 좋게 평가하는 경향이었다. (p<0.05) 위생성은 주부의 학력과 거주지에 따라 주부의 학력이 높을수록, 농어촌지역보다는 도시에 거주하는 주부일수록 시판제품이 더 비위생적이라고 평가하는 경향이었고(p<0.01) 포장에 대해서는 주택형태에 따라 농가나 아파트에 거주하는 주부가 단독주택이나 연립주택에 거주하는 주부보다 더 나쁘게 평가하는 경향이었다. (p<0.05) (9) 조사대상주부들은 시판제품의 가장 개선해야 할 점으로 위생성(37.0%), 가격(23.8%), 포장(15.6%), 맛(11.1%), 저장성(10.1%) 및 색(2.4%) 등의 순으로 지적하였고 주부의 거주지에 따라 대도시에 거주할수록 위생성을, 농어촌에 거주할수록 가격을 가장 개선해야 할 점으로 보는 경향이었다. (p<0.05)

• 한국의류학회지
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• 제33권7호
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• pp.1121-1127
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• 2009

This study presents an eco-friendly and one-step finishing method for modifying fiber property that reduces fiber damage in wool/polyester blend fabrics. Lipase from aspergillus oryzae is used in this experiment. The enzymatic treatment condition is optimized by measuring the relative activity of lipase depending on pH level, temperature, concentration of lipase, and treatment time. The concentration of $CaCl_2$as an activator is determined by the characteristics including whiteness, water contact angle (WCA), and dyeing property. The modified properties of lipase treated fabrics are tested for pill resistance and surface morphology. The results are described as follows: the optimum condions for lipase treatment constitute a pH level of 8.0, treatment temperature of 40$^{\circ}$$_C$, concentration of lipase at 100% (o.w.f), and a treatment time of 90 minutes. $CaCl_2$helps in raising lipase activation, and the optimum concentration is 50mM. The whiteness, wet ability, and pill resistance of lipase treated fabrics improves as compared to the control. The dyeing property of lipase treated fabrics improved by 53.5% after using the one-bath dyeing method. This means that lipase treatment can save time and cost during the dyeing process since lipase treatment modifies wool and polyester fibers. The surface of lipase treated wool fibers do not exhibit any change, however voids and cracks manifest on the surface of lipase treated polyester fibers.

• 한국의류학회지
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• 제33권2호
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• pp.213-221
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• 2009

This study provides the optimum papain treatment method and its effect on wool/polyester blend fabrics. The enzymatic treatment condition is optimized depending on its pH level, temperature, concentration of enzyme, treatment time and concentration of activators. The characteristics of samples treated with the papain are measured using weight loss, tensile strength, whiteness, WCA, dyeing property and surface micrographs. The results are described as follows: According to measuring weight loss, tensile strength and whiteness, a pH level of 7.5, $70^{\circ}C$, 10% papain(o.w.f.) and 60minutes of treatment time are optimized for papain treatment. L-cysteine and sodium sulfite are able to activate the papain. The optimum concentrations of them are 10mM and 50mM respectively. The WCA of fabrics is decreased since papain treatment makes wool/polyester blend fabrics more hydrophilic. Scouring with papain treatment improves whiteness and dyeing property of fabrics. The dyeing property of papain-treated fabrics is enhanced simply by a single step dyeing process using a basic dye. The surface of wool treated with papain in the presence of L-cysteine shows to be descaled. The surface of wool fibers in the presence of sodium sulfite, however, shows it is hydrolyzed evenly instead of being descaled. The surface of papain treated polyester fibers shows cracks and voids.

• 한국작물학회지
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• 제52권3호
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• pp.274-280
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• 2007

The effect of biofertilizer in enhancing nutrient quality and antioxidant property of rice grain was investigated. The experiment was carried out in a randomized complete block design with 3 replications and 7 treatments namely : RF = $N-P_2O_5-K_2O(11-5.5-4.8kg\;10a^{-1});$ half of the recommended fertilizer rate, $HRF=N-P_2O_5-K_2O(5.5-2.75-2.4kg\;10a^{-1}):$ HRF+Bio 250=HRF combined with 250 kg Biofertilizer 10 $a^{-1}$; HRF+Bio 500=HRF combined with 500 kg Biofertilizer 10 $a^{-1};$ Bio 250=250 kg Biofertilizer 10 $a^{-1};$ Bio 500=500 kg Biofertilizer 10 $a^{-1};$ and NF=No Fertilizer. Results showed that HRF+Bio 500 obtained a significantly higher protein content but a significantly lower amylose content compared with RF and NF treatments. Highest phytic acid content was recorded in NF treatment while the lowest was observed in HRF+500 treatment. The highest values in both electron donating ability and reducing power were obtained in HRF+Bio 500 treatment. All treatments obtained higher reducing power than that of the RF treatment and that NF treatment showed comparable values in both electron donating ability and reducing power with those of the treated plots. Highest antimutagenicity property was also observed in HRF+Bio 500 treatment followed by Bio 500 treatment. This study showed the possibility of using biofertilizer to enhance nutritional quality and antioxidant property of rice.

• Korean Chemical Engineering Research
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• 제40권6호
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• pp.735-740
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• 2002

고분자 필름의 무적성을 향상시키기 위하여 우수한 친수성 및 높은 가시광선 투과율을 보이는 유기-무기 혼성 코팅용액을 졸-겔법으로 합성하였다. 코팅용액은 입자 직경이 15 nm 크기의 무기물인 콜로이드 실리카 용액(Ludox)에 유기 조성을 함유한 화합물인 GPS을 첨가하여 제조되었다. 실란 커플링제인 GPS는 콜로이드 실리카와 주변의 매트릭스(matrix)인 고분자 필름에 각각 강한 결합을 형성하여 두 개의 서로 다른 물질을 강하게 연결하는 결합제 역할을 한다. 강산성 조건 하에서 제조된 혼성 코팅용액으로 고분자 필름 위에 코팅한 경우는 코팅필름의 표면이 거의 균열이 없는 매끈한 미세구조를 보이는 반면, 약산과 염기성 조건 하에서 제조된 혼성 코팅용액으로 코팅한 경우에는 균열이 심한 미세구조를 보였다. 또한 pH 2의 산성 조건에서 제조한 필름은 우수한 친수성 및 높은 가시광선 투과율을 보인 반면, 염기성 조건으로 제조한 코팅필름은 친수성이 좋지 않았으며, 낮은 가시광선 투과율을 보였다.