• 공업화학
• /
• 제9권5호
• /
• pp.758-762
• /
• 1998

유화중합을 이용하여 중량 평균입자크기가 $0.3{\mu}m{\sim}1.5{\mu}m$인 중공 라텍스 입자를 제조함에 있어 평균입자크기와 고형분 함량에 영향을 미치는 반응 인자를 조사하였다. 실험결과 유화제 (SDS)의 농도가 증가함에 따라 친수성 코어 폴리머의 크기가 작아졌으며, 친유성 스티렌 단량체 (styrene monomer)와 개시제 (SPS)의 첨가량이 증가함에 따라 중공입자의 크기가 커졌다. 한편, 친수성 아크릴산의 첨가속도가 증가함에 따라 중공입자의 크기가 작아졌다. 또한, 스틸렌 단량체의 첨가량이 증가함에 따라 에멀젼 폴리머의 고형분 함량이 선형적으로 증가하였다.

• 한국광물학회지
• /
• 제32권2호
• /
• pp.113-126
• /
• 2019

본 연구 목적은 비-가시성 금 형태로 산출되는 황화광물 정광을 마이크로웨이브-질산용출하여 황화광물을 효과적으로 용해시키고자 하였고, 고체-잔류물을 납-시금법을 적용하여 금을 회수하고자 하였다. 따라서 질산농도, 용출시간 그리고 시료 첨가량 효과에 대하여 마이크로웨이브-용출실험을 각각 수행하였다. 고체-잔류물의 무게 감소율은 질산농도가 증가할수록 그리고 용출시간이 증가할수록 증가하였지만 시료 첨가량이 증가하면 무게 감소율이 감소하였다. 마이크로웨이브-질산용출을 수행한 결과 질산농도 6 M에서, 마이크로웨이브 용출시간 18분에서 황철석이 완전히 사라진 것을 XRD 분석에서 확인하였다. 고체-잔류물에 대하여 납-시금법을 수행한 결과, 질산농도가 증가할수록 그리고 용출시간이 증가할수록 함량이 증가된 금 입자들을 회수하였다. 반면에 시료 첨가량이 증가할수록 금 함량이 감소하는 입자들을 회수하였다.

• 한국환경과학회지
• /
• 제31권1호
• /
• pp.1-8
• /
• 2022

In this study, solid-liquid separation conditions for coagulation and sedimentation experiments using inorganic coagulant (aluminum sulfate and Poly-Aluminum Chloride (PAC)) were optimized with brine wastewater discharged by the epoxy-resin process. When the turbidity and suspended solid (SS) concentration in raw wastewater were 74 NTU and 4.1 mg/L, respectively, their values decreased the lowest in a coagulant dosage of 135.0 - 270.0 mg Al³⁺/L. The epoxy resin was re-dispersed in the upper part of wastewater treated above 405.0 mg Al³⁺/L. The removal efficiencies of turbidity and SS via dosing with aluminum sulfate and PAC were evaluated at initial turbidity and SS of 74 - 630 NTU and 4.1 - 38.5 mg/L, respectively. They increased most in the range from 135.0 - 270.0 mg Al³⁺/L. The solid-liquid separation condition was quantitatively compared to the correlation of SS removal efficiency between the coagulant dosage and SS concentration based on the concentration of aluminum ions. The empirical formula, R = be^aD, shows the relationship between SS removal efficiency (R) and coagulant dosage (D) at 38.5 mg/L; it produced high correlation coefficients (r²) of 0.9871 for aluminum sulfate and 0.9751 for PAC.

• Journal of Pharmaceutical Investigation
• /
• 제27권4호
• /
• pp.295-301
• /
• 1997

Nitrendipine, a slightly soluble calcium channel blocking agent forms a solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$, which exhibits better dissolution characteristics than the uncomplexed drug. The dissolution rate of nitrendipine was markedly increased in solid dispersion system in pharmacopeial disintegration media at pH 1.2 and pH 6.8. Four different dosage forms of nitrendipine were administered to rats: (a) nitrendipine in the solution of PEG 400; (b) nitrendipine solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 by solvent evaporation method and administered in capsule form; (c) physical mixture of nitrendipine with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 and administered in capsule form; (d) nitrendipine alone administered in capsule form. Relative bioavailability after the oral administration of various dosage forms to rats with a dose of 10 mg/kg equivalent to nitrendipine was compared with that of nitrendipine in the solution of PEG 400. The AUC of solid dispersion was significantly bigger than that of nitrendipine powder. $T_{max}$ of solid dispersion was significantly shorter and $C_{max}$ was higher than that of nitrendipine powder. These results indicate that the bioavailability of nitrendipine could be improved markedly by inclusion complexation. An interesting correlation also appears to exist between the in vitro dissolution data and the area under the plasma concentration-time curves.

• 펄프종이기술
• /
• 제39권3호
• /
• pp.52-59
• /
• 2007

This paper confirms that high solid coating can increase coating speed and reduce drying cost. Low solid coating color with the synthetic thickener and high solid coating color with the rheology modifier and with higher ratio of GCC were prepared. Coated paper was then produced with an industrial coater, varying coating speed and dryer temperature in order to keep the moisture content of the coated paper constant. Coating color concentration was able to be increased from 66% to 69% and from 68% to 71% without an adverse effect on coating color rheology. With a help of the rheology modifier, the increased ratio of GCC in high solid coating did not show harmful effects on the coated paper quality.

• 한국안전학회지
• /
• 제29권4호
• /
• pp.123-131
• /
• 2014

Whole amount of waste water, approximately 921.6 liter, for cleaning a ready mixed concrete truck should be used to produce concrete as a mixing water or cleaning water. Recycling water for concrete mixing contains solids, which cause decrease in slump, air and compressive strengths, so it may influence on poor concrete quality. Therefore, it has been maintained to use recycling water with less than 3 percent of solids. Since no evaluation system has been constructed to directly reflect on variability of recycling water from ready mixed concrete plants, it is necessary to develop "Automatic recycling solid measuring system" for quality controls in real time. In this research, sensors measuring waste water concentration in ultrasonic and inductance methods were developed, and automatic system using the sensors were established. The accuracy of measurement sensors developed for recycling water based on various conditions of concentration was proved, and application limits were evaluated. Also, concentration of recycling water using sensors developed from ready mixed concrete plant was measured, and curing method verified the accuracy of the sensors. Moreover, measurement sensors for recycling water in various locations were installed to evaluate the effects on measuring method and spots. The automatic measuring system for recycling water concentration, which is developed in the research, will contribute to improve concrete quality safety through reliable solids maintenance.

• Preventive Nutrition and Food Science
• /
• 제8권3호
• /
• pp.230-234
• /
• 2003

Mass transfer characteristics during osmotic dehydration of carrots were studied as functions of immersion temperature and time, and sugar and salt concentrations. The effect of osmotic dehydration on the degree of browning of air-dried carrots was also evaluated. Increasing the immersion temperature and time, sugar concentration, and salt addition increased water loss, sugar gain, molality and rate of dehydration. The water loss and increases in solids, and molality were rapid in the beginning of the process and then increased slowly during remainder of the process. Increasing 1 or 2% salt concentration in the 40$^{\circ}$Brix sugar solution at 6$0^{\circ}C$ increased water loss and solid gain. Salt addition was not able to significantly affected on water loss and solid gain compare to temperature (40～8$0^{\circ}C$) and sugar concentration (20～60$^{\circ}$Brix) changes due to the low salt concentration. A minimum degree of browning of the air-dried carrots (O.D. = 0.048) could be achieved using binary solutions (40$^{\circ}$Brix sugar solution with 2% salt addition) with 24 min of immersion time compared to control (O.D. = 1.308) or blanching with 24 min of immersion time (O.D. = 0.174).

• 한국수산과학회지
• /
• 제39권6호
• /
• pp.437-440
• /
• 2006

To develop natural crab-like flavorants from red snow crab Chionoecetes japonicus cooker effluent (RSCCE), the flavor was analyzed during the concentration of RSCCE up to $40^{\circ}Brix$. Using solid phase microextraction (SPME)/gas chromatography (GC)/mass selective detection (MSD), 30 volatile flavor compounds were detected in four RSCCE samples (10, 20, 30, and $40^{\circ}Brix$). These comprised 12 aromatic compounds, 5 N-containing compounds, 2 5-containing compounds, 2 alcohols, 2 aldehydes, and 7 miscellaneous compounds. The amounts of all volatiles except alcohols and aldehydes increased significantly with the concentration (p<0.05). Of the volatiles detected, the most abundant was a dimethyl trisulfide with an odor like onion/cooked cabbage. Of the N-containing compounds (nutty, roasted peanut-like odor), 2-ethyl-5-methylpyrazine was the most abundant, followed by 2,5-dimethylpyrazine and 2-methyl-5-isopropylpyrazine in that order (p<0.05). The N- and S-containing compounds with characteristic odors detected in this experiment are thought to play a positive role in RSCCE during concentration.

• Current Optics and Photonics
• /
• 제4권5호
• /
• pp.441-445
• /
• 2020

A novel design for a Fresnel lens for a solar end-pumped laser is demonstrated in this paper. The new hybrid Fresnel lens includes two parts, inner and outer. The inner part is a twice-total-internal-reflection and vertical-transmission lens. The outer part is a once-total-reflection and vertical-transmission lens. The radius of the Fresnel lens is 600 mm, and its focal length is 750 mm. The concentrating performance of the Fresnel lens is examined using TracePro. The results show that the concentration efficiency has been greatly improved. The total concentration efficiency of the hybrid Fresnel lens reaches 73.2% when the radius of the laser rod is 3 mm. This design can simplify the concentration system of a solar end-pumped solid-state laser.

• 한국응용과학기술학회지
• /
• 제35권4호
• /
• pp.995-1002
• /
• 2018

Hairy root culture of ginseng is industrially prospected because the cultivation period of ginseng is relatively long. In this study, the effect of medium concentration and sucrose concentration on hairy root culture of ginseng was evaluated. The optimization of ginseng hairy roots transformed by Agrobacterium rhizogene were performed liquid medium. The MS(Murashinge & Skoog basal medium) concentration was selected with 1/2 strength MS and the optimal sucrose concentration was determined at 2-3%(w/v). At the optimum culture condition, The yield (the ratio of weight of grown hairy root cultures to weight of fresh ginseng hairy roots) and production rate of ginseng root were 19.42 times and 5.73 g/l-day. The major ginsenosides were Rb group, Re and Rg1. The produced total ginsenoside content in the solid medium was 9.87 (mg/g) and increased 1.34 times in the liquid medium (13.23 mg/g). In solid culture, the contents of ginsenosides Rb, Re and Rg1 were 2.14, 3.65 and 1.87 mg/g, respectively. In liquid culture, the contents of ginsenosides Rb, Re and Rg1 were 3.54, 4.12 and 2.63 mg/g, respectively.