• 한국식품영양과학회지
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• 제27권6호
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• pp.1110-1116
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• 1998

To determine the optimum conditions for the enzymic hydrolysis against wheat gluten of high con centrations (6~14%, w/w, protein), a hydrolysis system combining weak acid pretreatment and enzymic hydrolysis was investigated. Alcalase showed the highest DH(degree of hydrolysis) of the tested proteases. After hydrolysis by alcalase, subsequently peptidases were applied for the better DH of the wheat gluten hydrolyzate. Peptidase NP2 showed the highest DH of the tested peptidases, but flavour zyme was shown for the lowest bitter taste of the resulting hydrolyzate. In order to minimize aggregation or gelling at higher initial substrate concentration during heat treatment, wheat gluten suspension was pretreated with possibly low concentrations of hydrochloric acid at 105oC for 1 hour, and then enzy matically hydrolysed with alcalase and subsequently with flavourzyme. Each required minimum concen tration of hydrochloric acid in the wheat gluten suspension of 6, 8, 10, 12, and 14%(w/w, protein) was 0.10, 0.15, 0.20, 0.225, and 0.275N, respectively. After the subsequent enzymic treatment by alcalase and peptidase NP2 for 24 hrs, the nitrogen solubility in the final wheat gluten hydrolysates was increased to 94.9, 86.4, 85.3, 89.3 and 95.0%, and their amino nitrogen content was increased to 2.87, 5.68, 7.34, 9.71 and 12.50mg/m, respectively.

• 대한의용생체공학회:의공학회지
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• 제14권4호
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• pp.349-354
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• 1993

To investigate the relations between the physical constitutions, the acid-base balance, and the autonomic nervous function, the blood gas, the heart rate and the concentrations of Na, K of serum were measured pre-and poststimulation. As the result, it is shown that in the normal condition the macro-negative(strong liver- weak lung type) is the metabolic alkalosis, the macro-positive (strong lung-weak liver type) is the metabolic acidosis, the micro-negative(strong kidney-weak spleen type) is the alkalosis and the micro-positive (strong spleen-weak kidney type) is the acidosis. And the ntacro-positive and micro-positive are the sympathetic lead, the macro-negative and micro-negative are the parasympathetic lead. In the macro-positive and micro-positive subjects, the concentration of K in serum is relatively high. This si coincided with the acidosis. But in the macro-negative and micro-negative subjects, the concentration of K in serum is relatively low. This is coincided with the alkalosis.

• Transactions on Control, Automation and Systems Engineering
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• 제2권2호
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• pp.130-135
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• 2000

A two parameter model of a single fictitious weak acid with unknown dissociation constant has been successfully applied to design a neutralization system for many multi-component acid streams. But there are some processes for which above two parameter model is not satisfactory due to poor approxmation of the nonlinearity of pH process. Here, for etter control of wide class of multi-component acid streams, a three parameter model of a strong acid and a weak acid with unknown dissociation constant is proposed. The model approximates effectively three types of largest gain variation nonlinearities. Based on this model a nonlinear pH control system is designed. Parameters can eeasily estimated since their combinations appear linearly in the model equations and nonlinear adaptive control system may also be constructed just as with the two parameter model.

• 미생물학회지
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• 제7권3호
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• pp.115-124
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• 1969

The mash of Takjoo, Korean flour wine, is fermented through two brewing processes ; the primary brewing process to saccharify and the main one to produce ethyl alcohol. The activities of acid proteinase (pH3), weak acid proteinase (pH 6), and alkaline proteinase (Ph 80 on the processes are determined with time by the Folin phenol method as a strength of casein digestion. Hydrogen ion concentration, the content of total organic acids, protein, free amino acids and oligopeptides, which effect the activities of proteinase, are also measured. The results are briefly summarized as follows : 1. In general, the activities of acid proteinase and weak acid proteinase in the mesh of primary brewing process are stronger than those in main brewing process. 2. The activities of acid proteinase are remarkably stronger than those of weak acid proteinase in both processes. It reveals that they decrease slowly through the fermentation. Activities of alkaline proteinase are weaker than others. 3. As the raw materials are mixtured, the total amount of organic acids is equivalent to 0.150 mg/ml acetic acid in the mesh of primary brewing process and 0.02 mg/ml acetic acid in the main one. They increase gradually with time. 4. Hydrogen ion concnetration shows 3.9 in the mesh of main brewing process and 3.28 in the primary one. They increase to the maximum in 60-72 hrs., and decrease since 108 hrs. 5. The content of crude protein shows 66.90mg/ml in the mesh of main brewing process, while shows 64.29mg/ml in the mesh of primary one. they decrease slowly with time. it seems that a small content of crude protein, as a substrate, converts into amino acids and soluble nitrogen compounds by proteinase. 6. The content of free amino acids and oligopeptides shows 0.36 mg/ml in the mesh of primary brewing process and 0.24mg/ml in the main brewing process. It is evident that the reason they increase continuously through the fermentation is the effect of proteinase. 7. According to the results, the strong activities of proteinase in primary brewing process has been derived from the decrease of hydrogen ion concentration due to the production of organic acids.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.1-11
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• 2002

This study was conducted to investigate the effects of reaction pH conditions and hardener types on the reactivity, chemical structure and adhesion performance of UF resins. Three different reaction pH conditions, such as traditional alkaline-acid (7.5 → 4.5), weak acid (4.5), and strong acid (1.0), were used to synthesize UF resins which were cured by adding three different hardeners (ammonium chloride, ammonium citrate, and zinc nitrate) to measure adhesion strength. Fourier transform infrared (FT-IR) and carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopies were employed to study chemical structure of the resin prepared under three different reaction pH conditions. Adhesion strength of the resins cured with three different hardeners was determined with lap shear specimens in tension. The gel time of UF resins decreased with an increasing in the amount of both ammonium chloride and ammonium citrate added in the resins. However, the gel time increased for zinc nitrate. Both FT-IR and ¹³C-NMR spectroscopies showed that the strong reaction pH condition produce uronic structures in UF resin, while both alkaline-acid and weak acid conditions produce quite similar chemical species in the resins. The maximum adhesion strength was occurred with the resin prepared under strong acid pH condition. However, this study indicated that the weak acid reaction condition provide a balance between increasing resin reactivity and improving adhesion strength of UF resin. The measurement of formaldehyde emission from the panels bonded with the UF resins prepared is planned for future work.

• 한국생활과학회지
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• 제16권5호
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• pp.979-986
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• 2007

The purpose of this study is to investigate the dyeability, and the hand of soybean/cotton blended fabric after dyeing with natural and synthetic dyes. Soybean/cotton blended fabrics dyed with extracted solution from turmeric, sappan wood, gardenia and synthetic dyes(weak-acid dyes, reactive dyes, direct dyes). The hand value of soybean/cotton blended fabrics dyed with 6 different dyes was measured using Kawabata Evaluation System. The results are as follows; 1. The K/S value of the soybean/cotton blended fabric dyed with sappan wood extracts was the highest. 2. The color fastness of the soybean/cotton blended fabric dyed with reactive dyes was excellent. The fastness to the light of the same fabric was much better than the other fabrics. 3. Linearity of load-extension and tensile energy of the soybean/cotton blended fabric dyed with sappan wood extracts showed very high. Shear stiffness of the soybean/cotton blended fabric dyed with weak-acid dyes was much higher than that of fabric of dyed with reactive dyes. Bending property of the fabrics dyed with natural colorants(sappan wood, gardenia) showed very high, but that the fabric dyed with reactive dyes was very poor. 4. In the primary hand value, stiffness and anti-drape stiffness of the fabric dyed with weak-acid dyes showed the highest. Fullness and softness of the fabric dyed with weak-acid dyes showed very low.

• 한국식품과학회지
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• 제14권3호
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• pp.265-270
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• 1982

마이얄 갈색화반응의 중요한 중간생성체로 알려진 maltol, kojic acid, levulinic acid, furfural, 5-hydroxymethyl furfural(5-HMF)와 pryazine의 항산화작용을 조사하였다. 각 화합물의 작용은 이들 화합물의 0.01M의 농도로 들어있는 콩기름 기질들과 실험대조기질의 유도기간의 길이를 비교함으로써 추정하였다. 기질들은 $45.0{\pm}1.0^{\circ}C$에서 30일간 저장되었으며, 이들 기질의 과산화물값이 60 meq/kg oil가 되는데 소요된 시간으로써 그 기질의 유도기간으로 삼았다. 실험대조기질, kojic acid, 5-HMF, furfural, maltol, levulinic acid와 pyrazine의 유도기간은 각각 468, 592, 510, 498, 486, 450와 402시간 였었다. Kojic acid는 뚜렷한 산화방지작용을 갖고 있는 반면에 furfural와 5-HMF는 약한 작용을, maltol은 아주 약한 작용을 갖고 있었다. 한편, pryazine과 levulinic acid는 산화촉진작용을 보였었다. Pryazine은 뚜렷한 촉진작용을 보였으나, levulinic acid의 산화촉진작용은 매우 미약했었다.

• 공업화학
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• 제2권4호
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• pp.330-339
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• 1991

$V_2O_5-TiO_2/SiO_2$ 촉매를 제조하여 그 산특성을 조사하였고, 동 촉매상에서 o-자일렌의 무수프탈산으로의 부분산화반응에 대한 활성측정을 병행하여 촉매의 산특성과 반응성과의 연관성을 알아보았다. $V_2O_5$ 촉매는 V=O로 추정되는 약산점과 V-O-V로 추정되는 강산점을 가지고 있었으며, 소성온도가 높아질수록 약산점의 양이 감소하였다. $V_2O_5-TiO_2/SiO_2$ 촉매의 경우 약산점이 크게 나타났으며, 그 양은 $SiO_2$의 담지량이 20 mole% 일 때 최대치를 보였고 그 이상에서 일정하였다. 한편, o-자일렌 부분산화반응에서 $V_2O_5-TiO_2/SiO_2$는 $V_2O_5/SiO_2$에 비해 전체 전환율 및 무수프탈산으로의 선택도를 크게 증가시켰으며, $V_2O_5-TiO_2/SiO_2$에서 $TiO_2$의 양이 증가할 경우 전체 전환율은 증가하였으나 무수프탈산으로의 선택도는 크게 변하지 않았다. V=O로 추정되는 약산점은 o-자일렌을 약하게 흡착함으로써 무수프탈산으로의 부분산화반응을, V-O-V로 추정되는 강산점은 o-자일렌을 보다 강하게 흡착하여 $C_1$으로의 완전산화반응을 각각 유도함을 알 수 있었다.

• 대한화학회지
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• 제34권4호
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• pp.360-369
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• 1990

보로실리케이트와 HZSM-5 제올라이트 및 이들의 골격에 철이 일부 치환된 촉매를 제조하여 메탄올의 전환반응에서 촉매성질을 조사하였다. 산점의 세기와 양이 생성물 분포에 미치는 영향을 암모니아의 승온 탈착곡선으로부터 얻어진 산성도와 연관지어 고찰하였다. 강한 산점이 적은 보로실리케이트 촉매에서는 프로필렌 선택도가 높았으나, 강한 산점이 많은 HZSM-5 제올라이트 촉매에서는 방향족 화합물의 선택도가 높았다. 약한 산점이 전환반응에 기여하는지 여부는 확인되지 않았으나, 생성물 선택도는 강한 산점의 양과 관련지어 설명할 수 있었다. 철의 치환으로 약한 산점이 많아졌으나, 전화율이나 올레핀 선택도에는 영향이 없었다.

• 대한화장품학회지
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• 제13권1호
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• pp.29-35
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• 1987

Purely synthesized L-ascorbic acid 2 phosphate Mg salt (1 AsA PMg) improved the weak point of ascorbic acid which is easily decomposed in water solution. This compound is hydrolyzed with phosphatase of skin to corresponding ascorbic acid giving Vitamine C activities. The buffer solution of potassium acetate 0.5% and citric acid 0.005% and the sodium sulfite respectively showed good stabilizing effect of the AsA PMg solution. Compared to the other ascorbic acid derivatives the good solubility of AsA PMg gives broad application to cosmetic field.