• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.19-24
• /
• 2004

ED method is employed to effectively remove the organic acid salts in actual PDO fermentation broth. The lower electrical potential is selected to avoid the serious membrane fouling so as to ensure a stable and durative desalination process. Under the selected operation conditions, about 90% of organic acids salts are removed from PDO fermentation broth successfully by ED process. To reduce the loss of PDO product due to the diffusion, the operation time should be considered carefully. And based on mass balance equation and irreversible thermodynamics approach, a mathematical model is developed to describe the desalination process of an aqueous solution containing neutral solute by ED method. While the influence of concentration polarization is reflected by decreasing the conductivity of membrane, the model is verified well to describe the ED processes under varied operation conditions. Through the model, ED process of actual PDO fermentation broth is simulated to get a suitable scope of initial concentration in concentrated compartment.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.307-310
• /
• 2007

We describe effects of ionic and neutral additives on phase and structural behavior of the lyotropic chromonic liquid crystals used in preparation of optical elements such as polarizers and compensators.

• Membrane and Water Treatment
• /
• 제6권2호
• /
• pp.127-139
• /
• 2015

Rejection of ionic solutes by reverse osmosis (RO) and nanofiltration (NF) membranes is controlled mainly by electrochemical interaction as well as pore size, but it is very difficult to directly evaluate such electrochemical interaction. In this work, we used an inverse HPLC method to investigate the interaction between ionic solutes and poly (m- phenylenediaminetrimesoyl) (PPT), a polymer similar to the skin layer of polyamide RO and NF membranes. Silica gel particles coated with PPT were used as the stationary phase, and aqueous solutions of the ionic solutes were used as the mobile phase. Chromatographs obtained for the ionic solutes showed features typical of exclusion chromatographs: the ionic solutes were eluted faster than water (mobile phase), and the exclusion intensity of the ionic solute decreased with increasing solute concentration, asymptotically approaching a minimum value. The charge density of PPT was estimated to be ca. 0.007 mol/L. On the basis of minimum exclusion intensity, the exclusion distances between a salt and neutralized PPT was examined, and the following average values were obtained: 0.49 nm for 1:1 salts, 0.57 nm for 2:1 salts, 0.60 nm for 1:2 salts, and 0.66 nm for 2:2 salts. However, $NaAsO_2$ and $H_3BO_3$, which are dissolved at neutral pH in their undissociated forms, were not excluded.

• 접착 및 계면
• /
• 제19권2호
• /
• pp.55-59
• /
• 2018

본 연구는 신발의 겉창인 고무 접착공정에서 버핑, 산, 알칼리 프라이머 전처리 공정을 생략하여 공정의 간소화로 생산 효율을 높이기 위해 수용성염을 포함하는 고무에 대한 접착특성과 기계적 특성을 고찰하였다. 산성염, 염기성염, 중성염을 평가한 결과, 염기성염을 포함된 고무 성형물의 경우 수성 접착제에 대해 우수한 접착효과를 보였다. 이는 염기성염이 하이드로옥시염으로 존재함에 따라 고무표면이 친수화 되면서 수성접착제에 우수한 접착효과를 보였다. 이것은 접촉각 및 IR측정으로 확인할 수 있었다. 또한, 염기성염이 포함된 고무 성형물의 경우 가교밀도가 증가되어 마모 특성 및 경도는 증가하지만 가교시간을 지연시키는 요인으로 작용하였다.

• 한국잡초학회지
• /
• 제17권2호
• /
• pp.135-138
• /
• 1997

Sulfonylureas are highly active herbicides which can be applied at very low rate(10-50g/ha) to control broadleaf weeds. The nature of this category of compound is, however, very unstable toward hydrolysis. Therefore, the preparation of these compounds as liquid formulation was not possible. Most of the current formulations of sulfonylurea are in dry forms such as water dispersible granule or wettable powder. Even in these dry forms, the active ingredients also encounter significant chemical decomposition. This study involves the preparation of the sulfonylurea salts by reacting the parent compound with base such as sodium hydroxide. The salt becomes stable toward hydrolysis and it turns soluble when diluted with water. This discovery makes the preparation for liquid formulation or soluble granule of sulfonylurea possible. The stoichiometry of base added to the neutral sulfonylurea is controlled quite precisely. The base has to be added enough to quench the acidic impurities in the technical material and to convert the active ingredient into salt. However, the base should not be overused to cause further saponification of the sulfonylurea salts. The chemical nature of these compounds is presented and the chemical reaction is described. New soluble liquid formulation and solid granule formulation of sulfonylurea are suggested.

• Mycobiology
• /
• 제31권3호
• /
• pp.166-172
• /
• 2003

Chemical analysis of salted fish was analyzed in 60 samples collected from various moloha markets in Sohag, Qena and Aswan Governorates, Upper Egypt. Moloha contained 52.9% water content, while organic matter content represented 71.79% of dry weight and 33.81%($338.12{\pm}8.64mg\;g^{-1}$) of fresh weight. Total salts and soluble salts represented 13.29% and 10.19%($132.88{\pm}7.65\;and\;101.93{\pm}5.76mg\;g^{-1}$ of fresh weight), respectively. pH values were more or less neutral. Mycological investigation of examined samples revealed that fifty-five fungal species and one variety belonging to 11 genera were identified. The fungal genera of highest occurrence and their respective number of species were Aspergillus(A. flavus, A. niger, A. fumigatus, A. montevidensis, A. ficuum, A. parasiticus and A. mangini) and Penicillium(P. citrinum, P. puberulum, P. aurantiogriseum and P. roquefortii). On the other hand, yeast represented 18.2% and 3.0% of total counts of fungi on Czapeks-dextrose agar and 15%NaCl-Czapeks-dextrose agar media, respectively. Samples were assayed for potential presence of mycotoxins. Ten out of 60 samples(16.7%) were proved to be toxic. It is the first record of mycotoxins contamination of salted fish in Egypt. The ability of 340 isolates of recovered fungi was screened for production of mycotoxins and extracellular enzymes.

• 한국식품과학회지
• /
• 제14권2호
• /
• pp.151-155
• /
• 1982

Mucor plumbeus의 균체(菌體) 및 지방질생산(脂肪質生産)에 미치는 비타민류(類), 대사중간생성물(代謝中間生成物) 및 미량원소(微量元素)의 영향(影響)을 검토(檢討)하였다. 비타민류(類)의 최적 첨가량은 비오틴의 경우 $1{\gamma}/l$, 니코틴산, 피리독신, 티아민, 리보플라빈은 0.01 g/l이 었으며, 이들중, 피리독신의 효과는 현저하여 $37^{\circ}C$서 15일 배양시(培養時) 균체량(菌體量)과 지방질(脂肪質)의 함량은 각각 $2.82{\pm}0.14\;g/50ml$와 62.8%이었고 이 때의 트리글리세리드함량은 중성지방질(中性脂肪質)의 64.9%이었으며 주요구성 지방산(脂肪酸)은 올레산(50.0%), 리놀레산(23.88%)와 팔미트산(13.9%)이었다. 마론산은 지방질(脂肪質) 함량과 균체량(菌體量)은 증가(增加)시키나 트리글리세리드의 함량이 매우 낮으므로 바람직하지 못하다. 무기염류로서 $MgSO_4{\cdot}7H_2O$를 5g/l첨가하는 것이 다른 마그네슘염과 황산염들 보다 바람직하며, Mucor plumbeus는 균체생산(菌體生産)과 지방질(脂肪質)의 축적(蓄積)을 위(爲)하여 $NaH_2PO_4$를 필수적으로 요구하지는 않는다. 한편 $MnCl_2$의 2g/l첨가는 균체생산(菌體生産)과 지방질(脂肪質)의 함량을 증가(增加)시키는 효과(效果)가 있어 $37^{\circ}C$에서 15일간(日間) 배양시(培養時) 각각 $2.76{\pm}0.26\;g/50ml$및 59.4%이었고 이때의 트리글리세리드 함량은 중성지방질(中性脂肪質)의 73%이었다.

• 한국미생물·생명공학회지
• /
• 제44권3호
• /
• pp.303-310
• /
• 2016

In this study, doenjang samples were prepared with different types of salts (12%, w/w): purified salt (PS), 3-year aged solar salt (SS3), 1-year aged solar salt (SS1), and bamboo salt melted 3 times (BS). Whole-soybean mejus were fermented with starters consisting of 2 Bacillus strains, a yeast, and a fungus (starter doenjang), and control mejus were fermented with organisms present naturally in rice straw (non-starter doenjang). The whole-soybean mejus were dried, and then mixed with cooked soybeans and the respective salts. The doenjang samples were fermented for 13 weeks at 25℃. The protease (acid, neutral, and alkaline) activities, fibrinolytic activities, and antioxidant capacities of the samples were examined every week. BS doenjang showed the highest acid protease (6.46 ± 0.20 unit/g) and fibrinolytic activities (0.61 unit/ml). Among the starter doenjang samples, those made with SS and BS showed the highest total phenolic contents after 91 days of fermentation. For antioxidant activities, SS3 doenjang showed higher activities than the other doenjang samples, as evaluated by ABTS, DPPH, and FRAP assays. These results suggest that solar salt, especially aged for 3 years, is better than purified salt in terms of producing better functionalities of doenjang.

• 분석과학
• /
• 제8권4호
• /
• pp.675-682
• /
• 1995

Thin films of buckminsterfullerene($C_{60}$) formed by solution drop casting on Pt foil electrode surfaces were studied by cyclic voltammetry(CV) in acetonitrile(MeCN) containing quaternary ammonium or alkali-metal salts as supporting electrolyte. The electrochemical behaviors of $C_{60}$ films are found to be strongly dependent on the nature of the supporting electrolytes, especially with tetrabutyl ammonium perchlorate (TBAP, $NBu_4ClO_4$), and tetrabutyl ammonium tetrafluoroborate ($TBABF_4$, $NBu_4BF_4$). Reasonably stable films are formed into which electrons can be injected. The interaction of $C_{60}$ film with the quaternary ammonium cation may produce the fulleride salts $(TBA^+)(C{_{60}}^-)$ and $(TBA^+)_2(C{_{60}}^{2-})$. The bulk electroreduction with a controlled potential to generate the soluble $C{_{60}}^{3-}$ anions(dark red-brown color) is followed by electrooxidative deposition to produce a neutral $C_{60}$ film on the surface. The peak currents($I_{pc}$ and $I_{pa}$) of these thin film were dramatically decreased with repetitive potential scanning. These results could be explained by the adsorption-desorption phenomena and ion pairing interaction of reduced species($C{_{60}}^-$, and $C{_{60}}^{2-}$) onto the electrode surface. The peak current changes and peak potential shifts of the thin $C_{60}$ film in cyclic voltammograms formed from solution were observed by varying scan rates.

• 한국환경보건학회지
• /
• 제17권2호
• /
• pp.35-40
• /
• 1991

This study was performed to investigate the contamination degree of effluent from the sewage purification system and septic tank. The 711 samples, were collected from the large size tank located in Seoul from Mar. to June 1991. The results were as follows 1. The pH values of effluent were largely neutral of 6.96 in sewage and 7.43 in septic tank. 2. The average concentration of BOD was 48.18 mg/l in sewage and 127.0 rng/l in septic tank. 3. The average concentration of SS was 40.8mg/l in sewage and 90.5rng/l in septic tank. 4. In the analysis of nutrient salts, the average concentration of NH$_{3}$-N was 31.62mg/l in sewage and 88.79 mg/l in septic tank. 5. In the analysis of correlation among items, BOD, SS, NH$_{3}$-N and PO$_{4}$-P were higly correlated beween items. 6. As a results of above analysis, it is considered as desirable evaluation method of effluent not through the only item but through the integrated items.