• International Journal of Concrete Structures and Materials
• /
• 제9권3호
• /
• pp.381-390
• /
• 2015

Investigating the microstructure of hardened cement mixtures with the aid of advanced technology will help the concrete industry to develop appropriate binders for durable building materials. In this paper, morphological, mineralogical and thermogravimetric analyses of autoclave-cured mixtures incorporating ground dune sand and ground granulated blast furnace slag as partial cementing materials were investigated. The microstructure analyses of hydrated products were conducted using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), differential thermal analysis (DTA), thermo-graphic analysis (TGA) and X-ray diffraction (XRD). The SEM and EDX results demonstrated the formation of thin plate-like calcium silicate hydrate plates and a compacted microstructure. The DTA and TGA analyses revealed that the calcium hydroxide generated from the hydration binder materials was consumed during the secondary pozzolanic reaction. Residual crystalline silica was observed from the XRD analysis of all of the blended mixtures, indicating the presence of excess silica. A good correlation was observed between the compressive strength of the blended mixtures and the CaO/$SiO_2$ ratio of the binder materials.

• 한국식품조리과학회지
• /
• 제15권3호
• /
• pp.244-248
• /
• 1999

본 논문에서 돈혈을 사용한 순대와 돈혈을 혈장과 난백으로 대체한 순대의 성분 분석을 실시한 결과는 다음과 같다. (1) 돈혈을 15% 첨가한 순대의 일반성분은 수분 66.1%, 단백질 9.2%, 지방 10.4%, 회분 0.9%, 섬유소 0.5%, 탄수화물 12.7%였으며 Atwater계수로 환산한 총 칼로리는 181.92kcal/100g였다. 그러나 순대에 혈장을 대체함에 따라 163.78kcal/g으로 총 칼로리의 감소 효과를 나타냈으며 난백 첨가에 따라 총 칼로리가 230.77kcal/g으로 증가하였다. (2) 무기질은 돈혈 첨가 순대에서 Fe 함량이 8.50 mg%으로 우수한 철분 함유 식품이었으며 돈혈장, 난백 대체 비율 증가에 따라 Fe, Na, K의 함량이 감소하는 경향을 보였다. 그러나 Ca, P, Mg 함량은 시료군에 따라 유의적인 차이가 없었다. (3) 순대에서의 아미노산은 glutamic acid, leucine, lysine, glycine, alanine의 함량이 많았고 methionine, cysteine의 함량이 적었다. (4) 지방산은 palmitic acid, stearic acid, oleic acid. linoleic acid가 전체 지방산의 89.5∼93.5%를 차지하였다. 순대에서 돈혈장과 난백의 대체는 불포화/포화지방 산비와 다가불포화/포화지방산 비를 증가시키는 바람직한 영향을 주었다. 콜레스테롤 함량은 control인 혈액순대가 66.6 mg이었으나 혈장과 난백을 대체함으로써 각각 25.7%, 36.9%의 콜레스테롤 함량 저하 효과를 보였다.

• Membrane and Water Treatment
• /
• 제11권1호
• /
• pp.69-77
• /
• 2020

Former studies revealed that sepiolite thermally treated at high temperature have high adsorption capacity for phosphate. However, its micron size (75 ㎛) limits its application to water treatment. In this study, we synthesized sepiolite impregnated polysulfone (PSf) beads to separate it easily from an aqueous solution. PSf beads with different sepiolite ratios were synthesized and their efficiencies were compared. The PSf beads with 30% impregnated sepiolite (30SPL-PSf bead) possessed the optimum sepiolite ratio for phosphate removal. Kinetic, equilibrium, and thermodynamic adsorption experiments were performed using the 30SPL-PSf bead. Equilibrium adsorption was achieved in 24 h, and the pseudo-first-order model was suitable for describing the phosphate adsorption at different reaction times. The Langmuir model was appropriate for describing the phosphate adsorption onto the 30SPL-PSf bead, and the maximum adsorption capacity of the 30SPL-PSf bead obtained from the model was 24.48 mg-PO₄/g. Enthalpy and entropy increased during the phosphate adsorption onto the 30SPL-PSf bead, and Gibb's free energy at 35 ℃ was negative. An increase in the solution pH from 3 to 11 induced a decrease in the phosphate adsorption amount from 27.30 mg-PO₄/g to 21.54 mg-PO₄/g. The competitive anion influenced the phosphate adsorption onto the 30SPL-PSf bead was in the order of NO₃^- > SO₄^2- > HCO_3^-. The phosphate breakthrough from the column packed with the 30SPL-PSf bead began after ~2000 min, reaching the influent concentration after ~8000 min. The adsorption amounts per unit mass of 30SPL-PSf and removal efficiency were 0.775 mg-PO₄/g and 61.6%, respectively. This study demonstrates the adequate performance of 30SPL-PSf beads as a filter for phosphate removal from aqueous solutions.

• 한국항행학회논문지
• /
• 제15권2호
• /
• pp.298-306
• /
• 2011

본 논문은 팩시밀리를 위한 이진 영상 압축 표준인 JBIG2의 주요 구성모듈의 하나인 심벌 ID 코드 길이 부호화를 위한 런코드 부호기 IP를 하드웨어로 설계구현에 관한 것이다. VHDL코드 생성 및 하드웨어 합성을 위해서 ImpulseC Codeveloper와 Xilinx ISE/EDK 프로그램을 사용하였다. 합성된 하드웨어는 Xilinx사의 ML410 개발보드의 Virtex-4 FX60 FPGA에 다운로드하여 성능평가를 수행하였다. 합성된 하드웨어가 FPGA에서 차지하는 면적은 전체 slice의 13%를 차지하였다. 동작 검증을 위해 Active HDL 툴을 이용하여 각 IP에 대한 파형 검증을 수행한 결과 정상 동작함을 확인함으로써 하드웨어로의 구현에 적합성을 확인하였다. 아울러 ML410 개발보드 상에서 Microblaze CPU를 이용해 소프트웨어로만 수행한 경우와 동작 속도를 비교 한 결과, 구현된 하드웨어는 40배 이상의 빠른 처리 속도를 나타내었다. 구현된 하드웨어와 연동된 소프트웨어 모듈로 표준 CCITT문서를 압축한 결과 정상적으로 동작함을 확인하였다.

• 한국세라믹학회지
• /
• 제39권12호
• /
• pp.1133-1137
• /
• 2002

폐콘크리트 미분말과 고로 슬래그를 사용하여 유해 산업폐기물 고화용 시멘트를 제조한 후 수화성상과 압축강도를 평가하고 이 시멘트를 COREX 슬러지에 첨가하여 고화처리 하였다. 폐콘크리트 미분말과 슬래그 미분말을 1:1로 하고 여기에 포틀랜드 시멘트와 반수석고를 각각 10% 첨가하여 만든 고화용 시멘트로 사용 가능한 강도를 발현하고 있었다. 이 시멘트로 COREX 슬러지를 고화한 경우에 7일에서 140 kgf/$cm^2$을 상회하는 강도를 보여 폐슬러지를 고화시켜 안정화하는데 응용할 수 있음을 확인하였다.

• Macromolecular Research
• /
• 제12권4호
• /
• pp.422-426
• /
• 2004

Solid polymer electrolytes based on poly(ethylene glycol)-polyurethane (PEG-PU) complexed with LiClO$_4$ salt have been prepared by the solvent casting method. A PEG-PU material (PEG:4,4'-diphenylmethane diisocyanate: l,4-butanediol = 1:2:1) was synthesized through a typical two-step condensation reaction. We investigated the effects of the salt concentration on the ionic conductivity ($\sigma$) and the glass transition temperature (T$_{g}$ ) of the complex electrolytes by using alternating current impedance spectroscopy, differential scanning calorimetry, and dynamic mechanical thermal analysis. The measured values of both $\sigma$ and T$_{g}$ exhibited similar tendencies in that they had maxima within the range studied, probably because of two opposite effects, i.e., the increased number of carrier ions and the decreased chain mobility (or increased T$_{g}$ ) caused by the increase in the salt concentration. The highest conductivity, on the order of 2.43 ${\times}$ 10$^{6}$ S$cm^{-1}$ /, was obtained at an [O]/[Li$^{+}$] ratio of ca. 16 (0.92 ㏖ salt per kg of matrix polymer).

• 동아시아식생활학회지
• /
• 제24권6호
• /
• pp.723-738
• /
• 2014

This study examined nutrient intake of long-lived men and women living in Jeollanam-do (Gangjin, Goksung, Gurye, Damyang, Boseong, Suncheon, Jangheung) which is known as representative Korean longevity area. Using the 24 hr recall method, dietary nutrient intake data were collected from 134 subjects (67 for 80~89 years old, 67 for more than 90 years old) in spring and fall 2012. Nutrient for each subject were calculated using CAN-pro. Subjects' daily mean intake levels of macronutrients, vitamins and minerals were higher in fall than in spring. Compared to KDRIs, subjects less than recommend (RNI/AI). East consumed nutrients compared to KDRIs were folate, potassium, calcium, vitamin $B_1$, vitamin $B_2$ and vitamin E. Subjects 232.8~363.1% of recommended intake level for natrium. The nutrient adequacy ratio (NAR) was 0.87 for subjects in their 80s and 0.79 for than 90 years old. The average NAR of all subjects was 0.83. The index of nutritional quality (INQ) exceeded 1 for most nutrients except for Ca (0.87), K (0.77), vitamin $B_1$ (0.84), vitamin $B_2$ (0.70) and folate (0.68). The average INQ was 1.31. This study concluded that even though long-lived men and women living in Jeollanam-do consumed less than RNIs, nutrition consumption quality was relatively fine based on NAR and INQ results.

• 동아시아식생활학회지
• /
• 제27권5호
• /
• pp.500-511
• /
• 2017

This study was conducted to investigate the anthropometric data, bone density, serum profiles, nutrient intakes and diet quality of premenopausal and postmenopausal women. For the study, we obtained data for analysis from the combined 2008~2011 Korean National Health and Nutrition Examination Survey (KNHANES). The height and weight were 157.8 cm and 58.7 kg in premenopausal women and 155.5 cm and 58.3 kg in postmenopausal women, respectively. The obesity rate was 27.49% in premenopausal women and 34.98% in postmenopausal women (p<0.001). Total cholesterol, LDL-cholesterol, triglyceride, GOT, GPT and alkaline phosphatase in postmenopausal women were significantly higher than those in premenopausal women (p<0.001). The prevalence of osteoporosis was 0.0~0.89% in premenopausal women and 0.48~13.22% in postmenopausal women (p<0.001). In postmenopausal women, rates of hypertension, stroke, myocardial infarction, depression, and diabetes were significantly higher than those in premenopausal women. Water, fat. ash, sodium, retinol, thiamin, riboflavin and niacin intakes in premenopausal women were significantly higher than those in postmenopausal women. Water, fiber, Ca, and, K intakes were below KDRIs (Dietary Reference Intakes for Koreans) in both groups. The mean adequacy ratio (MAR) of premenopausal women was higher than that of postmenopausal women (p<0.001). The index of nutritional quality (INQ) in premenopausal women was also higher than that of postmenopausal women except iron and vitamin C. Therefore dietary guidelines and an education program should be developed for desirable improvement of health, bone density, nutrient status and dietary quality of postmenopausal women.

• Bulletin of the Korean Chemical Society
• /
• 제34권8호
• /
• pp.2251-2255
• /
• 2013

Second-order rate constants ($k_{HOO^-}$) for the nucleophilic substitution reactions of Y-substituted-phenyl diphenylphosphinates (4a-4i) with $HOO^-$ in $H_2O$ have been measured spectrophotometrically. The ${\alpha}$-nucleophile $HOO^-$ is 10-70 times more reactive than the reference nucleophile $OH^-$ although the former is ca. $4pK_a$ units less basic than the latter, indicating the ${\alpha}$-effect is operative. The Bronsted-type plot for the reactions of 4a-4i with $HOO^-$ is linear with ${\beta}_{lg}=-0.51$, a typical ${\beta}_{lg}$ value for reactions which were reported to proceed through a concerted mechanism. The Yukawa-Tsuno plot is also linear with ${\rho}=1.40$ and r = 0.47, indicating that a negative charge develops partially on the O atom of the leaving group, which can be delocalized to the substituent Y through resonance interactions. Thus, the reactions have been proposed to proceed through a concerted mechanism. The magnitude of the ${\alpha}$-effect (i.e., the $k_{HOO^-}/k_{HO^-}$ ratio) decreases linearly as the leaving-group basicity increases. It has been concluded that solvation effect is not solely responsible for the ${\alpha}$-effect found in this study but the transition-state stabilization through an intramolecular H-bonding interaction is also responsible for the ${\alpha}$-effect.

• 한국식품과학회지
• /
• 제20권2호
• /
• pp.245-251
• /
• 1988

Thermolysin 을 Dowex MWA-1에 10% glutaraldehyde로 고정화하였으며, 이 고정화 thermolysin을 사용하여 연속적응유(連續的凝乳)를 행(行)하였다. Thermolysin의 고정화수율(固定化收率)은 25%이었다. 고정화 thermolysin은 1/200M $Ca^{++}\;ion$의 존재하에서 $60^{\circ}C$의 고온에서도 안정하였으며 이 온도에서의 half-life는 16일이었다. 원료 milk를 pH 7.0이 되도록 조정하여 $55^{\circ}C$로 유지된 고정화 thermolysin column을 통과 시 켜 분해시킨 후, Streptococcus cremoris를 접종하여 응유(凝乳)시켜 curd를 얻었으며, 이렇게 하므로써 미생물오염이 방지될 수 있었으며 연속적응유를 효과적으로 행할 수 있었다. 고정화 thermolysin을 사용하여 얻은 cheddar type의 cheese는 rennet을 사용한 전통적인 방법으로 만든 cheese 와 거의 비슷하였다.