• 한국세라믹학회지
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• 제43권1호
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• pp.28-32
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• 2006

Diarylethene in photochromic materials was doped in organic-inorganic hybrid low-melting glasses were synthesized through a nonaqueous acid-base reaction process, which consists of network units including a small number of bridging oxides. The organic phase is a dichlorodimethylsilane while the inorganic phase is a tin(II) chloride. Diarylethene was incorporated into the glasses without any degradation of its functionality. The open form of diarylenthene, which is converted from the opening one upon UV-irradiation, is change to the closed form visible light-irradiation. The rate constant of the photochemical reaction is $31.78\times10^{-3}s^{-1}$ with 400 W UV lamp irradiation.

• 한국축산식품학회지
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• 제40권3호
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• pp.338-349
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• 2020

The effects of organic Zn-L-selenomethionine (Zn-L-SeMet) at 0.3 ppm on carcass composition, meat characteristics, fatty acid composition, glutathione peroxidase activity, and ribonucleotide content were compared against the commercial inorganic sodium selenite (Na-Se) and the combination of the two, in commercial broilers. A total of 540 one day-old chicks were assigned at random to 3 dietary treatments : i) commercial inorganic selenium as control or T1, ii) a 1:1 ratio of inorganic and organic selenium as T2, and iii) organic selenium as T3. Carcass composition, meat characteristics, cholesterol content, fatty acid composition, and ribonucleotide content were generally unaffected by treatments. However, discrepancy were significantly observed in glutathione peroxidase activity (GSH-Px) and water holding capacity, with organic selenium showing higher glutathione peroxidase activity (p<0.01) and lower shrinkage loss (p<0.05), respectively. These findings could be explained by the contribution of organic selenium in bioavailability of GSH-Px. However, having conducted in a commercial close house system with sufficient amount of nutritional supplementation, the present study demonstrated little or no effects of organic Zn-L-SeMet on meat characteristics, fatty acid composition, and ribonucleotide content (flavor characteristic) in broiler chickens.

• Applied Biological Chemistry
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• 제25권3호
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• pp.161-165
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• 1982

홍삼갈변(紅蔘褐變)의 적합(適合)한 촉진방법(促進方法)을 구명(究明)하기 위하여 인삼(人蔘)에 당(糖), amino산(酸) 및 무기질소화합물(無機窒素化合物)을 처리(處理)한 결과(結果) 당류중(糖類中)에서는 maltose와 glucose가 가장 강(强)한 갈변축진작용(褐變促進作用)을 나타내었다. amino산(酸)은 basic amino acid인 lysine, histidine, arginine이 가장 크게 촉진(促進)했으며 당(糖)과 amino산(酸) 혼합처리(混合處理)에서는 glucose와 glutamic acid 혼합처리구(混合處理區)가 가장 크게 촉진(促進)되었다. Glucose농도별(濃度別) 처리시(處理時)의 갈변촉진효과(褐變促進?果)는 glucose농도(濃度)가 증가(增加)함에 따라 갈변(褐變)이 촉진(促進)되었으며 무기질소화합물중(無機窒素化合物中)에서는 $urea>(NH_4)_2HCO_3>CH_3COONH_4$등의 순(順)으로 갈변(褐變)이 촉진(促進)되었다.

• 폴리머
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• 제37권2호
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• pp.184-195
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• 2013

아크릴 점착테이프는 자동차, 전기전자 및 디스플레이 모듈 접합에 사용된다. 본 연구는 이러한 모듈 접합에 사용되는 고강도 준구조형 점착테이프 제조를 위해 2-ethylhexylacrylate(2-EHA)와 acrylic acid(AAC)를 사용하여 UV 조사에 의한 광중합 및 점착테이프 제조를 위해 광경화를 진행하였고, AAC의 함량 및 무기물 충전제 $SiO_2$ 함량에 따라 아크릴 점착테이프의 물성에 미치는 영향을 고찰하였다. 공단량체로 사용된 AAC의 함량이 많을수록 아크릴고분자 사슬의 강직성이 증가하여 초기 점착력이 낮았고, 시간경과에 따라 점착력이 증가하였으며 테이프의 젖음성, 접촉각 및 SEM 이미지를 통해 확인할 수 있었다. 충전제를 첨가하지 않은 점착테이프의 박리강도와 전단접착강도는 반비례 관계였으나 충전제를 첨가하면 함량 증가에 따라 박리강도 증가와 함께 전단접착강도가 증가하는 비례관계를 보였다. 이러한 상관관계로부터 고강도 준구조형 접착물성을 필요로 하는 용도에 최적화된 아크릴 점착테이프를 제시할 수 있었다.

• 산업기술연구
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• 제23권A호
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• pp.199-206
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• 2003

The charcoal-encapsulated methyl silica microcapsules were prepared by a O/W microemulsion sol-gel method, and the adsorption properties on aquatic humic acid were investigated. The capsules prepared were spherical, $100{\sim}1000{\mu}m$ in size. The size distribution was controllable by adjusting the size of charcoal powder, charcoal/methyl silica ratio, and agitating speed in O/W sol-gel process. Adsorption efficiency of charcoal for aquatic humic acid was decreased after encapsulation by methyl silica shell. The decreased adsorption efficiency can be dependent on the decrease of the BET surface area and pore volume after encapsulation. Diffusion properties of humic acid through the capsule shell also played an important role on adsorption efficiency. Therefore, the reasonable target pollutants for the capsules can be VOC or odor molecules which can overcome diffusion barrier through shell of capsules in air condition. Functionalization methods for the charcoal-encapsulated $CH_3(SiO)_n$ microcapsules by incorporation of $TiO_3$ as a phtocatalytic function and by incorporation of inorganic pigment as a color function were also investigated. $TiO_2$ coating properties were controllable by adjusting pH, temperature, and the concentration of $TiOSO_4$. In XRD measurement, the crystal form of the coated $TiO_2$ was anatase. For the colorization of the capsules, inorganic pigments were more efficient than organic dyes, and various color was introduced to the capsules using inorganic pigments.

• 분석과학
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• 제5권3호
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• pp.277-283
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• 1992

질산, 염산, 황산 그리고 질산과 염산의 1:1 혼산의 농도를 변화시키면서 유도결합 플라즈마 원자방출분광법(ICP-AES)의 신호크기에 미치는 산의 영향을 연구하였다. 거의 모든 측정원소의 신호크기가 감소되었다. 산의 존재로 인한 감소는 산 농도가 1% 이상 될 때 심하게 눈에 띄었고, 사용된 산 중에서 황산에 의한 감소가 가장 심했으며 그 정도를 예측하기 힘들었다. 산의 농도를 변화시키면서 측정 원소의 신호크기 대 Ar 신호크기의 비, 그리고 Mg II 신호크기 대 Ma I 신호의 비를 측정하였다. 이 연구에서, 신호크기 감소의 주된 원인은 플라즈마 들뜸특성의 변화에 의한 것이 아니고, 분무효율의 변화, 예를 들면 droplet 크기분포, 점도와 표면장략의 변화 등인 것으로 판명되었다. 유도결합 플라즈마 질량분석법(ICP-MS)에서는 신호크기의 감소와 이온화 에너지와의 상관관계는 발견되지 않았다.

• The Korean Journal of Ceramics
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• 제5권3호
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• pp.278-283
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• 1999

Formaldehyde has widely been used for the cross-linking of polyvinyl alcohol polyvinyl alcohol polymer. The effects of formaldehyde on the water resistance of MDF cement composites were investigated as a function of types of catalyst, base or acid, and the amount of formaldehyde. The acetalization, reaction of OH group of PVA with aldehyde, was ended incompletely under base atmosphere. However, by addition of citric acid, the cross-linking of PVA polymer could be acheved through acetalization of PVA and formaldehyde. The effects of these different patterne according to the types of catalyst on the water resistance of MDF cement were studied by the preparation of PVA films and MDF composites. Thanks to the cross-linking reaction of PVA polymer chains by formaldehyde, the modified PVA films and MDF composites showed a good water-resistant propety. The modified MDF cement composite to which 3 wt% formaldehyde and 1 wt% cirtic acid were added showed 80% of initial flexural strength and good interfacial state between cement grain and polymer matrix. However, 4 wt% formaldehyde deteriorted the processing conditions, microstructures and eventually the flexural strength, causing sharp increase in the viscosity of sample dough during the mixing process. To study the relatins of flexural strength and interface of cement grain and polymer matrix, SEM and MIP measurement were performed.

• Environmental Analysis Health and Toxicology
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• 제21권1호
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• pp.1-11
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• 2006

Arsenic is a ubiquitous element found in several forms in environment. Although certain foods, such as marine fish, contain substantial levels of organic arsenic forms, they are relatively low in toxicity compared to inorganic forms. In contrast, arsenic in drinking water is predominantly inorganic and very toxic. Chronic ingestion of arsenic-contaminated drinking water is therefore the major pathway posing potential risk to human health. World populations are exposed to low to moderate levels of arsenic of parts per billion (ppb) to thousands of ppb. When exposed to human, it could metabolize into monomethylarsonous acid ($MMA^{III}$) and dimethylarsinous acid ($DMA^{III}$) which are highly toxic. Lots of stuides have been recently focused how $MMA^{III}\;and\;DMA^{III}$ induce toxic insults in various target tissues. Epidemiological studies revealed that chronic arsenic exposure caused cancer, cardiovascular diseases, and diabetes etc. In this review, the current understanding of arsenic on health effects will be discussed.

• 한국세라믹학회지
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• 제49권1호
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• pp.72-77
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• 2012

In the preparation of a hydroxyapatite [HAp]/gelatin [GEL] nanocomposite, the GEL matrix in aqueous solution of $H_3PO_4$ was modified by the introduction of aspartic acid [Asp], asparagine [Asn], and glycine [Gly]. The addition of Asp, Asn and Gly greatly affected the slurry formation of HAp/GEL nanocomposite and the resulting dry body showed variations in toughness with the addition of the different amino acids. The introduction of Asn into HAp/GEL nanocomposite was effective for producing the organic-inorganic interaction between HAp and GEL, and caused the increase of toughness. The formation reaction of the modified HAP/GEL nanocomposites was investigated by using XRD and FT-IR. The organic-organic interaction between the GEL matrix and the additives of Asp, Asn and Gly was confirmed from FT-IR analysis, and the organic-inorganic interaction between HAp nanocrystallites and the modified GEL matrix was also discussed, using FT-IR spectra patterns. Nanocrystallites of HAp were covalently bound with the GEL macromolecules and differently influenced by the modification species of Asp, Asn, and Gly.

• 원예과학기술지
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• 제18권6호
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• pp.808-810
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• 2000

참다래 수액을 이용 음료수을 제조하기 위해 수액내 화학성분을 조사하였다. 참다래 수액에서 수분 함량, 당도, pH, 산 함량, 탁도 및 점성은 각각 99.6%, 0.90%, 6.50, 0.15%, 0.60, 1.01로 나타났다. 수액내 유리당은 fructose, glucose, sucrose, galactose, manitol가 함유되어 있었는데 당의 대부분은 fructose였다. 수액내 주요 무기물은 칼슘, 칼륨 및 마그네슘으로 칼슘 함량이 상대적으로 가장 높았다. 수액에는 10종의 아미노산이 함유되어 있었는데 이들 중 주요 아미노산은 glutamic acid, lysine 및 isoleucine이었는데 이중 glutamic acid함량이 가장 높았다. 수액을 이용 제조한 다래수액 음료수(252mL)내 영양소 함량에서 당은 21.2g, 칼슘 23.1mg, 칼륨 14.1mg, 아미노산 554.5mg, 비타민 C 15.0mg/252mL이었다.