• Food Science and Biotechnology
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• 제17권1호
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• pp.114-117
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• 2008

Chelating agents to sand lance fish sauce for the prevention of precipitate formation were applied. The precipitates consisted of crude protein (74.4%), ash (18.7%), and other components (6.9%). Sand lance sauce was mainly composed of glutamic acid (3.69 mg/g), alanine (2.96 mg/g), and lysine (2.64 mg/g). However, there was an increase in the amount of hydrophobic amino acids, phenylalanine, isoleucine, and leucine, in the precipitates. Sodium ions were not detected in the precipitate; rather, the main elements were Mg ($1.98{\times}10^4\;{\mu}g/g)$, K ($1.36{\times}10^4\;{\mu}g/g)$, and Ca ($6.66{\times}10^2\;{\mu}g/g)$. In HPLC analysis, fish sauce was composed of 2 main peaks with molecular weights of 85.5 and 528.4 Da, respectively. However, the precipitate contained one peak with a molecular weight of 1,513.5 Da. The addition of 0.2% malic acid and citric acid caused 55 and 70% prevention of the precipitate, respectively. Citric acid was the most effective chelating agent and efficiently prevented precipitation in the fish sauce.

• 한국주조공학회지
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• 제21권5호
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• pp.280-285
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• 2001

Nb-containing austenitic stainless steel is widely used as exhaust frame and diffuser assembly in power plant. However, this steel is known to be difficult to produce by the continuous casting process due to the surface cracks. Therefore, the continuous casting technology was developed for the prevention of the surface cracks on CC slabs. Precipitates and the analysis of heat trasfer in a slab were investigated in order to find out the formation mechanism of surface cracks on cc slabs It was found that surface cracks are occurred due to the NbC precipitates, which are formed along the grain boundaries around $800^{\circ}C$. The secondary cooling pattern has been developed to produce the defect free CC slabs of Nb-containing austenitic stainless steel.

• 한국재료학회지
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• 제14권1호
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• pp.9-12
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• 2004

Metallic impurities, such as Fe, Cu, and Au, become generation and recombination centers for minority carriers when combined with oxide precipitates or silicon self-interstitial clusters. As these centers may cause leakage and discharge in silicon devices, their prevention through gettering of the metallic impurities is an important issue. In this article, key aspects of intrinsic gettering, such as oxygen control, wafer cleaning, device area denudation, and bulk oxygen precipitation are discussed, and a practical method of implementing intrinsic gettering is outlined.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.419-427
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• 1996

To solubilize practically insoluble biphenyl dimethyl dicarboxylate (DDB), which has been used for the treatment of chronic hepatitis as tablets or hard capsules, the solubilities of DDB in various hydrophilic, oily and hydrocarbon vehicles, and aqueous surfactant solutions were measured by high performance liquid chromatography. It was found that, among the vehicles studied, polyethylene glycol (PEG) 300 revealed the best solvency, and the solubility reached 17.6 mg/ml at 37$^{\circ}C$. The addition of glycyrrhizic acid ammonium salt (GAA) to DDB-PEG 300 solution (5-20 mg/g) inhibited the formation of precipitates, and at the concentration of 10 mg/g, any precipitaction was not observed even after 2 years at 4$^{\circ}C$. Furthermore, GAA markedly enhanced the permeation of DDB through the rabbit duodenal mucosa in a concentration dependent manner. The addition of copolyvidone (ca. 1.0%) to DDB-GAA-PEG 300 system (1 : 0.5 97.5 w/w) was most effective in preventing the considerable precipitation of DDB-PEG 300 solution (7.5 mg/750 mg) when mixed with water of 300-900 ml at 37$^{\circ}C$. GAA showed a synergistic effect in the prevention of precipitate formation. This finding suggests that this DDB formulation may form less precipitation when DDB soft capsules disintegrate and diffuse into the gastrointestinal fluid, resulting in improving the bioavailability Dissolution rate of DDB (7.5 mg) from sort elastic capsules of DDB-GAA-PEG 300 system was rapid. The supersaturation state was maintained for 2 hr at the concentration of 7.35$\pm$3.3 mg in 900 ml of water without precipitation. The total amount of DDB dissolved from this new formulation was 5.3 and 6.1 times higher, when compared to marketed DDB tablets (25 mg) and capsules (7.5 mg), respectively.

• 마이크로전자및패키징학회지
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• 제16권2호
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• pp.27-31
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• 2009

Sn whiskers can grow from the pure Sn and high Sn-based finish and cause the electrical shorts and failures. Even with the wealth of information on whiskers, we have neither the clear understanding of whisker growth nor methods for its prevention. In this study, the whisker grain roots which connected with intermetallic layer were analyzed by high-resolution transmission electron microscopy (HR-TEM). In the Sn-Cu plated leadframe (LF) that was stored at ambient condition for 540 days, filament-shaped whiskers were grown on the Sn-plated surface and ${\eta}'-Cu_6Sn_5$ precipitates were widely distributed along the grain boundaries at the Sn matrix. The measured of the lattice fringes at the ${\eta}'-Cu_6Sn_5$ was $4.71{\AA}$ at the coarse grain and $2.91{\AA}$ at the fine grain. The $Cu_3Sn$ which generates the tensile stresses was not observed. The formation of $Cu_6Sn_5$ precipitates and intermetallic layer were strongly related to whisker growth, but, the whisker growth tendency does not closely relate with the geometric morphology of irregularly grown intermetallic compound (lMC).

• 대한금속재료학회지
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• 제46권6호
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• pp.329-337
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• 2008

During the continuous casting of boron-bearing steel, the corner cracks on the slab are formed by deformation with low strain rate and rapid cooling at the unbending temperature within the range of 800- $1000^{\circ}C$. Especially, the rapid cooling in the corner of slab during the continuous casting leads to as corner cracking. Therefore, in this study, the hot tensile tests applied to the different cooling rates were taken into account in order to study the effect of cooling rate on the hot ductility of boron-bearing steel. The results revealed that increasing cooling rate deteriorate the hot ductility of boron- bearing steel. Rapid decreasing of the hot ductility is caused by formation of a film-like ferrite and precipitate at the austenite grain boundaries. The morphology of the precipitates in the boron-bearing steel was monitored by PTA (Particle Tracking Autoradiography) and TEM, we observed MnS and BN compound and their morphology was quite different depending on the cooling rates. When the cooling rate is increased, rodshape MnS and BN precipitates can be formed along the austenite grain boundaries. It can cause that weakening the boundary region and decreasing the hot ductility of boron-bearing steel.

• 정신신체의학
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• 제4권1호
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• pp.91-97
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• 1996

Lithium is a widely used important drug in the treatment of manic-depressive illness and its prevention of relapse. However, this drug has a Low therapeutic index, therefore, it has many attendant side effects. The most prevalent renal effect of lithium is impairment of concentrating ability and this defect appeared into overt polyuria. A renal lesion is confined to the collecting tubule and 12-20% of patients taking lithium suffer from nephrogenic diabetes insipidus. This nephrogenic diabetes insipidus causes the states of extracellular fluid depletion, hypernatremia and precipitates lithium intoxication. In such situation, symptoms of nephrogenic diabetes insipidus and lithium intoxication are very similar, so we should be very cautious to discriminate them. We herein report a patient characterized by a prolonged stuporous state, hypernatremia and severe nephrogenic diabetes insipidus during lithium therapy.

• 자원리싸이클링
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• 제28권3호
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• pp.15-20
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• 2019

폐수내 질소와 인을 이용한 struvite 회수는 수계 부영양화 방지 및 비료자원화에 효과적인 기술이나, 해결해야 할 이론 및 기술적 문제점이 있다. 본 연구에서는, 기존 문헌의 상세한 검토를 통하여, 이론적 측면에서 적절한 반응식 선정 및 이론적 고찰을 이용한 struvite 생성 반응예측 가능성을 논의하고, 기술적 측면에서는 struvite 생성의 대표적인 저해물질인 Ca의 배제를 통해 struvite 결정의 순도를 높일 수 있는 효과적인 방법을 소개하려 한다. 반응예측 측면에서는 중성~염기성 pH 영역에서 효과적인 struvite 반응식 및 반응계수를 이용, 정량적 모델을 구축할 수 있다. 이러한 모델은 실제 회분식 실험결과와 잘 일치하며 특히 이온들의 charge balance도 함께 고려하여 struvite 생성시 희석된 수용액에서 흔히 동반되는 pH 저하를 합리적으로 예측할 수 있다. 한편, Ca의 배제를 통한 struvite 순도 향상은 ${HPO_4}^{2-}-P$ 대비 고농도의 ${NH_4}^+-N$을 조성하여 해결할 수 있는데, 이는 고농도 암모늄 이온의 존재가 struvite 생성 관련 열역학적 구동력을 강화시켜 인산염이 Ca 대신 고농도 암모니아와 용이하게 반응하여 struvite 생성에 유리한 이온환경을 조성하기 때문이다. 즉 인산염이 $Ca^{2+}$과 빠르게 반응하여 이미 침전물이 형성하였을지라도, 고동도 암모늄으로 인한 열역학적 구동력으로 인산-칼슘 침전물이 재용해 되어 struvite를 생성시킬 수 있다.

• 한국표면공학회지
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• 제49권2호
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• pp.166-171
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• 2016

Cathodic protection is widely recognized as the most cost effective and technically appropriate corrosion prevention methodology for the port, offshore structures, ships. When applying the cathodic protection method to metal facilities in seawater, on the surface of the metal facilities a compound of calcium carbonate($CaCO_3$) or magnesium hydroxide($Mg(OH)_2$) films are formed by $Ca^{2+}$ and $Mg^{2+}$ ions among the many ionic components dissolving in the seawater. And calcareous deposit films such as $CaCO_3$ and $Mg(OH)_2$ etc. are formed by the surface of the steel product. These calcareous deposit film functions as a barrier against the corrosive environment, leading to a decrease in current demand. On the other hand, the general calcareous deposit film is a compound like ceramics. Therefore, there may be some problems such as weaker adhesive power and the longer time of film formation uniting with the base metal. In this study, we tried to determine and control the optimal condition through applying the principle of cathodic current process to form calcareous deposit film of uniform and compact on steel plate. The quantity of precipitates was analyzed, and both the morphology, component and crystal structure were analyzed as well through SEM, EDS and XRD. And based on the previous analysis, it was elucidated mechanism of calcareous deposit film formed in the sacrificial anode type (Al, Zn) and current density (1, 3, $5A/m^2$) conditions. In addition, the taping test was performed to evaluate the adhesion.

• 한국미생물·생명공학회지
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• 제35권2호
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• pp.163-172
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• 2007

본 연구는 효모 내에서 생합성된 유기게르마늄을 함유한 게르마늄강화효모 Geranti Bio Ge-Yeast 내에 무기게르마늄이 존재하지 않거나 불검출임을 확인하기 위해 수행하였으며, 이를 뒷받침하기 위한 과학적 논거를 제시하기 위해 $GeO_2$ 정성분석 프로토콜을 수립하여 실험을 실시하였다. 1당량의 $NaBH_4$를 $GeO_2$에 가하면 갈홍색의 침전이 관찰되고 2당량의 $NaBH_4$를 가하면 진한 갈색의 침전이 생성되는데 이 독특한 색을 띠는 침전 생성으로부터 $GeO_2$의 존재를 정성적으로 분석이 가능하였다. $SiO_2$와의 반응 시 색 변화가 일어나지 않는 것으로 보아 색은 Ge-O와 B간의 결합에 의해 생기는 전하이동 전이 때문일 것으로 생각되며, 게르마늄강화효모와의 반응에서는 발색이나 침전이 형성되지 않아 $GeO_2$가 존재하지 않음을 확인하였다. 투석막 외부의 여과액을 취하여 상기 $GeO_2$ 정성 프로토콜에 따라 $NaBH_4$와 반응을 시도하여도 특이한 색 변화와 갈홍색 침전이 관찰되지 않았으므로 투석막을 통과하여 외부에 존재하는 게르마늄도 역시 $GeO_2$의 형태가 아닌 유기게르마늄일 것으로 사료된다. Geranti Bio Ge-Yeast는 생합성 기법을 사용하여 생산된 게르마늄을 강화한 유기게르마늄으로서 더 다양한 분석과 연구를 통해 각각의 single compound들의 구조를 규명하고 분리 정제하는 연구가 필요하리라 사료된다.