• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.1-5
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• 1996

Rapid analytical method was investigated to determine precursors of N-nitrosamine such an nitrite and nitrate in squid(Illex illecebrosus and Sepiell maindroni), codfish(Gadus marcrocephalus)and flatfish(Paralichthys olivaceus) by ion chromatography(IC) and colorimetric methods. Recoveries of nitrite and nitrate in fish tissues were 89~98.7% and 94.1~99.8% for IC, and 98.4~103.7% and 67.7~102.2% for colori-metric method, respectively. Using IC, nitrite was not detected and nitrate was 0.89~1.23mg/kg, while using colorimetric method, nitrite and nitrate were NO~0.08mg/kg and 0.3~0.42mg/kg, respectively. Therefore, the IC method showed better recoveries, and was applicable to extract nitrite and nitrate simultaneously, and is simpler compared with colorimetric method in analyzing nitrite and nitrate from fish tissues.

• 대한금속재료학회지
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• 제48권3호
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• pp.262-267
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• 2010

$LiNi_{1-x}Mg_xO_2$(x=0, 0.025, 0.05, 0.075, 0.1) samples were synthesized by the solid-state reaction method. The crystal structure was analyzed by X-ray powder diffraction and Rietveld refinement. $LiNi_{1-x}Mg_xO_2$samples give single phases of hexagonal layered structures with a space group of R-3m. The calculated cation-anion distances and angles from the Rietveld refinement were changed with Mg contents in $LiNi_{1-x}Mg_xO_2$. The thicknesses of $NiO_2$ slabs were increased and the distances between the $NiO_2$ slabs were decreased with the increase in Mg contents in the samples. The electrical conductivities of sintered $LiNi_{1-x}Mg_xO_2$ samples were around $10^{-2}$ S/cm at room temperature. The electrochemical performances of $LiNi_{1-x}Mg_xO_2$were evaluated by coin cell test. Compared to $LiNiO_2$, $LiNi_{0.95}Mg_{0.05}O_2$ exhibited improved high-rate capability and cyclability due to the well-ordered layered structure by doping of Mg ion.

• 멤브레인
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• 제27권3호
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• pp.240-247
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• 2017

본 연구에서는 막 결합형 축전식 탈염공정에 적용을 위해 폴리비닐플루오라이드를 고분자 지지체로 사용하여 양이온 및 음이온교환수지를 배합하여 제작된 불균질 이온교환막을 탄소전극에 결합하여 염 제거 효율을 알아보고자 하였다. 불균질 이온교환막의 배합 조건은 용매, 고분자 지지체, 이온교환수지를 7 : 2 : 1의 무게 비율로 하였으며 탄소전극에 직접 캐스팅 하였다. 운전조건으로 공급액은 주로 NaCl 수용액에 대하여 흡착전압, 시간, 공급액의 농도, 유속, 탈착전압, 시간 등에 대하여 염 제거 효율을 측정하였으며 이 외에 $CaCl_2$과 $MgSO_4$ 수용액에 대하여서도 측정하였다. 대표적으로 NaCl 100 mg/L 용액의 15 mL/min에서 1.5 V, 3분의 흡착조건, -0.1 V, 3분의 탈착조건에서 98%의 염 제거 효율을 보였으며, $CaCl_2$과 $MgSO_4$는 100 mg/L, 15 mL/min에서 1.2 V, 3분의 흡착조건, -0.5 V, 5분의 탈착조건에서 각각 70, 59%의 염 제거 효율을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.525-528
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• 2004

The ion-induced secondary electron emission coefficient ${\gamma}$ and work function for MgO thin film with $O_2$ plasma treatment has been investigated by ${\gamma}$ -FIB (focused ion beam) system. The MgO thin film deposited from sintered material with $O_2$ plasma treatment is found to have higher ${\gamma}$ and lower work function than those without $O_2$ plasma treatment. The energy of various ions used has been ranged from 100eV to 200eV throughout this experiment. It is found that the highest secondary electron emission coefficient ${\gamma}$ has been achieved for 10 minutes of $O_2$ plasma treatment under RF power of 50W.

• 한국안전학회지
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• 제19권3호
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• pp.40-44
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• 2004

To the removal of hardness materials, we've test the absorptive capacity of main material $Mg^{2+},\;Ca^{2+}$ on the using the activated carbon powder saturated in 0.1M Nitrilotriacetic acid by experimental methods. The absorptive properties of $Ca^{2+}\;and\;Mg^{2+}$ were measured with absorbent quantity and contact time., and investigated the physical properties of overall rate constant and adsorption constant adsorption isotherm, and Langmuir and Freundlich constant. In case of k' adsorption rate constants of $Ca^{2+},\;Mg^{2+}$, was 0.00299, 0.00529 by Bhattahary and Venkobachar equation. $k_{aa}$ was 0.00373, 0.00640 according with adsorption rate constants of Lagergren.

• 대한환경공학회지
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• 제39권9호
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• pp.505-512
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• 2017

NaA 제올라이트 분말(Z-PA) 및 펠렛(Z-BA)를 이용하여 수중의 Sr 이온의 흡착특성을 검토하였다. 회분식 실험에서 Z-BA와 Z-PA에 의한 Sr 이온의 흡착은 유사 1차식보다는 유사 2차식에 잘 부합되었고, 등온 흡착실험 결과는 Langmuir 등온식에 잘 부합하였으며, 이 등온식으로부터 구한 최대 흡착량은 Z-PA는 233.32 mg/g, Z-BA는 164.60 mg/g이었다. 연속식 실험에서 Sr 이온의 농도가 증가함에 따라 Sr 이온의 총 흡착량(q)는 증가하였으나 파과시간, 처리 부피($V_{eff}$) 및 총 제거율(R)은 감소하였다. 실험으로부터 구한 파과곡선은 Thomas 모델식에 의해 잘 모사되었다.

• 한국재료학회지
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• 제11권9호
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• pp.759-762
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• 2001

Mg$_2$SnO$_4$having an inverse spinel structure was selected as a new host material of $Mn^{2+}$ activator. The luminescence of the $Mg_2$SnO$_4$:Mn phosphor prepared by the solid-state reaction were investigated under ultraviolet and low-voltage electron excitation. The Mn-doped magnesium tin oxide exhibited strong green emission with the spectrum centered at 500nm wavelength. It was explained that the green emission in $Mg_2$SnO$_4$:Mn phosphor is due to energy transfer from $^4T_1to ^6A_1\;of\; Mn^{2+}$ ion at tetrahedral site in the spinel structure. The optimum concentration of $Mn^{2+}$/ion exhibiting maximum emission intensity by the low-voltage electron excitation was 0.6mol%. ？

• 한국식품영양과학회지
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• 제46권2호
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• pp.220-228
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• 2017

본 연구는 수산동물을 원료로 한 천연 anserine의 추출을 위해 여러 추출방법을 이용하여 연어로부터 anserine을 추출하였으며 각 추출방법에 따른 불순물(protein, iron)과 anserine의 함량 변화를 살펴보았다. Anserine 추출용 시료로서 연어의 적합성을 알아보기 위해 아미노산 함량을 분석한 결과 전체 아미노산 함량 중 anserine은 약 43.06%를 차지하는 것으로 나타나 추출용 시료로 적합한 것으로 나타났고, 추출방법에 따른 함량 변화를 살펴보기 위해 가열처리와 한외여과처리, 그리고 이온교환 및 한외여과처리를 이용한 추출방법에 따른 함량 변화를 살펴본 결과 $60^{\circ}C$, $80^{\circ}C$, $100^{\circ}C$로 가열 처리한 경우 $100^{\circ}C$ 가열처리구가 총철과 단백질 등 불순물 제거에 가장 효과적이었으나, anserine 함량의 감소가 큰 것으로 나타났다. 한외여과방법을 통해 분자량을 조절한 추출물의 함량 변화를 측정한 결과에서는 가열처리 추출물보다 단백질 약 81%, 총철 함량이 약 97% 감소하는 결과를 나타내었으며, anserine의 함량 변화는 가열처리구와 비슷한 수준을 유지하였다. 또한, Dowex $1{\times}8$ 수지를 이용하여 1차 이온교환을 하고 이온 교환한 추출물을 이용하여 MW 500까지 한외여과처리를 한 후 CM-cellulose를 이용하여 2차 이온교환을 병행한 추출물의 함량 변화를 살펴본 결과, 가열-한외여과처리 추출물보다 단백질 및 총철의 함량은 감소했지만 상대적으로 높은 anserine 함량을 나타내어 이온교환-한외여과처리 추출방법이 단백질 및 총철과 같은 불순물의 함량은 낮추면서 상대적으로 anserine의 함량을 높일 수 있는 추출방법이라 사료된다. 또한, 이러한 경향은 전기영동 및 HPLC를 통해 확인할 수 있었으며, LC/MS를 이용하여 표품 anserine과 1차 이온교환-한외여과처리 추출물, 2차 이온교환 추출물을 분석한 결과 모두 동일한 분자량(MW 240)을 가진 물질로 확인되어 1, 2차 이온교환 및 한외여과처리를 병행한 추출법이 anserine의 추출에 있어서 효율적인 방법으로 생각한다.

• 한국물환경학회지
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• 제32권5호
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• pp.442-449
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• 2016

The goal of this study is to provide basic data to establish a foundation for the provision of safe drinkable water. The raw water of natural mineral water was analyzed to determine the quantities of anions (F^-, Cl^-, NO_3-N^-, and SO₄^2- ) and cations (Ca²⁺, K⁺, Mg²⁺, and Na⁺) during the former and latter half of 2016. Analysis of the current quality of the raw water of natural mineral water among domestic manufacturers showed average anions contents of 0.46mg/L of fluorine, 8mg/L of chlorine ion, 1.5mg/L of nitrate nitrogen, and 12mg/L of sulfate ion. While the fluorine content was greater than the water quality criterion of 2.0mg/L at four points, the fluorine level was overall stable. The average cations contents included 21.3mg/L of calcium, 1.0mg/L of potassium, 3.4mg/L of magnesium, and 9.6mg/L of sodium. The chemical characteristics were compared among the major ions, and the results are presented in a piper diagram. The content ratio of cations was in the order of Ca²⁺> Na⁺>Mg²⁺>K⁺, whereas that of anions was in the order of SO₄^2->Cl^->NO_3-N^->F^-. While the cations were slightly scattered, the anions were generally concentrated except for at a few points. The Ca-Na-HCO₃ type was dominant overall in water sources from diorite, gneiss, and granite, while the Na-Mg-Ca-HCO₃-Cl type was dominant in basalt sources. Mineral water manufacturers source their water under various conditions, including in-hole casing, excavation depth, and contact state of bedrock; even within the same rocky area, some differences in the water quality type can occur. When the depth of the water source was taken into account, the mean anions contents of F^-, Cl^-, NO_3-N^-, and SO₄^2- were similar, with no significant differences according to depth. Of the cations, K⁺ and Na⁺ showed no significant differences across all the tubular wells, whereas Ca²⁺ and Mg²⁺ decreased in content with depth.

• The Korean Journal of Physiology
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• 제20권2호
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• pp.199-208
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• 1986

The effects of $Mg^{++}$ upon the spontaneous contraction activated by 1 IU/l oxytocin were studied in the isolated rat uterine muscle. Longitudinal muscle strips u·ere prepared from the rat uteri at the estrous stage. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) In the uterine strips contracting spontaneously, as $Mg^{++}$ concentration increased in the Tyrode solution the amplitude of peak tension decreased in all the experimental solutions containing the various concentrations of $Ca^{++}\;(0.5{\sim}4 mM)$. And the amplitude of peak tension increased in inverse proportion to the $[Mg^{++}]/[Ca^{++}]\; ratio$. It is suggested that the tension-lowering effect of $Mg^{++}$ would be developed through decreasing intracellular ionized free calcium ion concentration by uncertain mechanism. 2) The frequency of the uterine contraction activated by oxytocin increased as the $[Mg^{++}]/[Ca^{++}]\;ratio$ ratio increased up to 1/2, but the frequency decreased above this ratio. It is speculated that $Mg^{++}$ would influence the excitability control action of $Ca^{++}$.