• 한국환경과학회지
• /
• 제12권4호
• /
• pp.469-476
• /
• 2003

In order to examine the pre-treatment effect of crab shell en Pb$^{2+}$ removal by crab shell in aqueous solution, acid and alkali pre-treated crab shell were used. Electron microscopy techniques such as TEM (transmission electron microscopy) and SEM (scanning electron microscopy), and EDX (energy dispersive X-ray) and FTIR (Fourier transform infrared) spectrometry techniques were used to investigate the process of Pb$^{2+}$ removal by acid and alkali pre-treated crab shell. The Pb$^{2+}$ removal by acid pre-treated crab shell was much lower than that by untreated crab shell because of the decrease of CaCO$_3$ from the crab shell. However, the Pb$^{2+}$removal by alkali pre-treated crab shell increased compared to that by untreated crab shell. The results were confirmed by TEM, SEM, EDX and FTIR.nd FTIR.

• 한국염색가공학회지
• /
• 제12권6호
• /
• pp.380-388
• /
• 2000

The porosity of polyester fibers treated with sodium hydroxide aqueous solution was investigated using a nitrogen porosimeter, and the dyeability of the treated fibers was discussed in terms of the porosity. In pore distribution, the polyester fibers treated with sodium hydroxide aqueous solution were characterized by higher amount of pores below $10\AA$ than those of the untreated fibers, and by shift of the pore size having maximum accumulated volume from $10\AA$ for the untreated fibers to $5~6\AA$. As the weight loss of the polyester fibers treated with sodium hydroxide aqueous solution increased, BET surface area and total pore volume increased linearly, but average pore size, showing some different aspect, increased steeply at earlier stage and then approached the maximum value. The dye uptakes of the polyester fibers treated with sodium hydroxide aqueous solution increased with the BET surface area, the total pore volume and the average pore size. The alkali treatment increased the surface area of polyester fibers, so that the chance of contact between the fiber and dye molecules increased. In addition, the pores created on the surface of polyester fibers by alkali treatment might act as pathways for dye molecules into the polyester fibers.

• Korean Membrane Journal
• /
• 제4권1호
• /
• pp.36-40
• /
• 2002

The diffusion coefficients of ions in the reverse transport system using the carrier mediated membrane were estimated from the diffusional membrane permeabilities and the ion activity in membrane system. In the aqueous alkali metal ions-membrane system diffusional flux of alkali metal ions driven by coupled proton was analyzed. The aqueous phase I contained NaOH solution and the aqueous phase II also contained NaCl and HCl mixed solution. The concentration of Na ions of both phases were $10^{0},\;10^{-1},\;10^{-2},\;5{\times}10^{-1}\;and\;5{\times}10^{-2}\;mol{\cdot}dm^{-3}$ and the concentration of HCI in aqueous phase II was always kept at $1{\times}10^{-1}\;mol{\cdot}dm^{-3}$. Moreover, the carrier concentration in liquid membrane was $10^{-2}\;mol{\cdot}dm^{-3}$. The results indicated that the diffusion coefficients depend strongly on the concentration of both phases electrolyte solution equilibriated with the membrane. The points were interpreted in terms of the energy barrier theory. Furthermore, eliminating the potential terms from the membrane equation was derived.

• 한국응용과학기술학회지
• /
• 제32권2호
• /
• pp.188-193
• /
• 2015

고로슬래그는 유동성 장기강도 및 내구성이 좋고 수화열을 낮아 경화체를 제조함에 따른 적용성이 우수하지만, 몇 가지 문제점을 갖는다. 시공시간이 증가하고 회전속도가 늦고 초기강도가 낮다. 본 연구에서는 알칼리활성화를 이용한 경화체 제조에 있어 필요한 알칼리 수용액을 해수담수화 과정에서 발생하는 농축수의 전기분해를 통하여 공급하였으며. 알칼리 수용액을 이용하여 고로슬래그와 경화체를 제작하였다. 결과는 다음과 같이 요약할 수 있다 : 모르타르의 압축강도는 NaOH 2%이하일 때는 감소하고, 6% 이하까지는 증가한다. 그리고 NaOCl의 함량이 증가할수록 압축강도도 증가한다. 그러나 NaCl이 모르타르에 존재하면 초기강도보다 재령 28일차 강도는 감소하게 된다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.421-421
• /
• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.

• 한국인쇄학회지
• /
• 제20권1호
• /
• pp.16-27
• /
• 2002

Recently, the attraction for water-based ink is increasing, Because Solvent ink, based on organic solvent, cause bad effect on environment and rise the cost. Instead of organic solvent that cause environment pollution as well as cost-rise by rise of petroleum price, Binder based on alkali-soluble resin is popular and studied by many other country. However, in domestic, research and development for alkali-soluble resin is not like, because of lack of understanding environmental pollution and safety, therefor alkali-soluble resin development and research for the properties of the water-based ink used by alkali-soluble resin is not study very well. In this paper, we studied dispersion of carbon black in acrylic resin solution and the properties of water-based ink used by carbon black and acrylic binder.

• 동력기계공학회지
• /
• 제20권1호
• /
• pp.42-49
• /
• 2016

This study showed that on-site ferrate(VI) solution was synthesized by wet oxidation method and applied aqueous 2,4-dichlorophenol(DCP) solution to evaluate the degradation efficiency. On-site ferrate(VI) solution was synthesized by putting $FeCl_3{\cdot}6H_2O$ in the strong alkali solution with NaClO and NaOH and applied DCP solution directly. DCP solution was extracted by the liquid-liquid method and analyzed by GC-ECD. The factors such as pH, DCP initial concentration, injected ferrate(VI) dosage, temperature were investigated. The optimum pH and temperature conditions of DCP degradation were obtained in neutral condition and $35^{\circ}C$. And the experimental results showed that DCP removal efficiency also increased with the decrease of DCP initial condition and the injected ferrate(VI) dosage.

• 한국세라믹학회지
• /
• 제22권3호
• /
• pp.72-76
• /
• 1985

Single crystals of the compound MeI $(LiMoO_4)$ and $Me^I(LiWO_4)$ ($Me^I=K$, Rb, Cs) were synthesized by slow evaporation from aqueous solution and bycooling from melt. The compounds of potassium or rubidium are hygroscopic and they form easily hydrated crystals $Me^I LiMoO_4$.$H_2O$ or $Me^ILiMoO_4$.$H_2O$ or $Me^ILiWO_4$.$H_2O$ from aqueous solution. The structures of these hydrated crystals are each other isotypic and they are built up of distorted layers of $(LiMoO_5)$ or $(LiWO_5)$. There exist two types of tetrahedral framework structures in this group of anhydrous molybdates and tung-states ; tridymite-type and cristobalite-type. $KLiMoO_4$ and $KLiWO_4$ have two types of polymorphic structures where as only the cristobalite-type is found in the Rb-and Cs-compounds. The system $KLiSO_4-KLiMoO_4$ was studied. Two components are almost immiscible but there eixst a narrow area of solid solution on the side of sulfate in the system.

• 한국도로학회논문집
• /
• 제14권6호
• /
• pp.37-43
• /
• 2012

PURPOSES : This study is to evaluate the feasibility of setting the standard of cement alkali content by using ASTM C 1260(accelerated mortar bar test) METHODS : This study analyzes the ASR(alkali silica reaction) expansion of cement mortar bar based on the changes in the aggregate type(fine, coarse), cement type(ordinary, low alkali), and replacement contents of fly ash. ASR tests were conducted according to ASTM C 1260. RESULTS : In this test results, There is no big difference in the ASR expansion between ordinary cement and low alkali cement. From this test results, it was found that the variation of cement alkali content did not have a effect on ASR expansion because mortar bar was placed in a container with sufficient alkali aqueous solution at high temperature during the test process of ASTM C 1260. CONCLUSIONS : It is evidently clear that the alkali content of cement have a effect on ASR. But ASTM C 1260 is difficult to assess this effect.

• 한국의류학회지
• /
• 제26권2호
• /
• pp.349-354
• /
• 2002

In order to decolorize the reactive dye wastewater, we investigated the dye-adsorption ability of chitin, which was natural polymer obtained from shrimp shell. Chitin particle(less than 250 ${\mu}{\textrm}{m}$n) was prepared from shrimp shells in the processes of decalcification in aqueous hydrochloric acid solution and deproteination in aqueous sodium hydroxide solution. The particle size of chitin was controlled to less than 250 ${\mu}{\textrm}{m}$. Three tripes of the reactive dyes-C.I. Reactive Red 120, C.I. Reactive red 241 and C.I. Reactive Black 5-were used. Dye adsorption ability of chitin was investigated by dipping the particle in the dyebaths of concentration of 0.0l%, 0.03% and 0.05% for various periods of time(1,3,5, 10,20,40,80,160minutes). The influence of addition of salt(Na$_2$SO$_4$) and alkali to the dyebaths on dye-absorption was also investigated. We obtained the following results fur the dye-absolution ability of chitin in the dyebaths of three types of reactive dyes. 1) The amount of dye uptake by chitin was increased by addition of salt to the dyebaths. 2) As the concentration of alkali became higher than 3g/I, the amount of dye uptake by chitin was increased. Chitin showed good dye-adsorption ability, when the alkali concentration was high. 3) Chitin showed equal dye uptake in the three types of dyebaths when the dye concentration was 0.0l%. Over 90% of dyestuffs was adsorbed from the dyebaths in ten minutes. When the dye concentration was higher, better adsorption ability was showed in a dye bath of Reactive black 5 than in the others. When the dye concentration was 0.03%, 90% of Reactive red 120 and Reactive red 241 was adsorbed in 40 minutes and the same of Reactive black 5 in 10 minutes. When the dye concentration was 0.05%, 9()% of Reactive red 120 was adsorbed in 80 minutes, and Reactive black 5 in to minutes.