• 한국수산과학회지
• /
• 제2권1호
• /
• pp.71-82
• /
• 1969

The present investigations were carried out with the purpose of making clear the fundamental features of the seasonal variations in chemical composition of the brown algae. Three species of samples, Ecklonia cava, Sargassum sagamianum and Hizikia fusiforme have been analyzed monthly for their contents of total ash, crude protein, alginic acid, mannitol, and laminarin over a year period. Three kinds of samples were collected from the same locality, situated on the southern coast of the Che-ju Island, from September 1966 to August 1967. In addition, the comparative analysis was made on fronds and stipes of the plant for their chemical composition. The results obtained are summarized as follows: 1, In general, the three species examined underwent a similar mode of seasonal variation, and no essential difference was detected among them. 2. The chemical composition of the plant exhibited a considerable difference between the species. The content of total ash in H. fusiforme was remarkably higher than those in the two other species respectively. The alginic acid content was relatively high in S. sagamianum and low in H. fusiforme. The contents of crude protein, mannitol and laminarin were appreciably high in E. cava and low in H. fusiforme in general. 3. The most outstanding feature in the seasonal variation was that, in general, the total ash, crude protein, and alginic acid contents were at a maximum in the winter months while laminarin and mannitol contents were at a minimum. The converse was true in summer. Total ash-Maximum values were observed from December to February and minimum from August till October. Crude Protein-All species exhibited maxima in January and February, and minima from August to October. Alginic acid-Maximum contents occured from January to March and minimum from September to November. Mannitol-The maximum content of mannitol was In May and lune and minimum in January, February and March. Leminerin-Maximum content was in September and October, and minimum in January and February. 4. The wide seasonal variation in chemical constitution occured in the fronds, but the stipes showed a slight seasonal variation. In the chemical composition, the stipe was high in alginic acid, low in mannitol and laminarin. The reverse was in the frond.

• Bulletin of the Korean Chemical Society
• /
• 제30권9호
• /
• pp.2011-2016
• /
• 2009

To resolve the differentiation problem of acetone and acrolein in the analysis of carbonyls by high-performance liquid chromatography (HPLC), we investigated the optimum analytical conditions for their separation. Carbonyl compounds were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated cartridges. We examined the influence of three experimental variables: temperature (25, 30, 40, 50 and 60 ${^{\circ}C}$), flow rate (1.0 and 1.2 mL/min), and relative mobile phase composition (among acetonitrile, water and tetrahydrofuran). The experimental results revealed the optimum analytical condition of a flow rate of 1.2 mL/min, temperature of 32 ${^{\circ}C}$ and mobile phase composition of acetonitrile: water: tetrahydrofuran = 34 : 52.8 : 13.2. The analysis of indoor air composition indicated that acrolein and acetone comprised 11% and 42% of all aldehydes, respectively.

• 한국세라믹학회지
• /
• 제26권5호
• /
• pp.670-676
• /
• 1989

The PbTiO3 is well known materials having remarkable ferroelectric, piezoelectric, and pyroelectric properties. PbTiO3 thin films with a perovskite structure were successfully fabricated on titanium substrate by chemical vapor deposition. These films were characterized according to composition, crystal structure, and electrical properties. Semi-quantitative compositional analysis of the deposited films was made by Auger Electron Spectroscopy(AES). The PbTiO3 film deposited on titanium substrate at the deposition temperature 75$0^{\circ}C$, the Ti(C2H5O)4 fraction 0.15, and O2 partial pressure 0.06atm, has a columnar structure and grows with(001) preferred orientation, and has stoichiometric composition. A clear dielectric transition and offset in the dc conductivity near the transition temperature(48$0^{\circ}C$) were observed in the deposited lead titanate film.

• 한국공작기계학회논문집
• /
• 제15권1호
• /
• pp.133-137
• /
• 2006

Ion permeability characteristics in nano-polymer membrane structures are performed to investigate the chemical composition and characteristics of MEA(Membrane Electrolyte Assembly) which is one of the most important parts to decide the performance in PEMFC(Polymer Electrolyte Membrane Fuel Cell) system. Subsequently, the MEA manufacturing process is presented for the uniformed MEA product. In the meantime, the analysis of SEM(Scanning Electron Microscope) is carried out in order to investigate the joint aspect and chemical composition of MEA. As a result of SEM analysis, it is found that the bonded catalyst and carbon composition contain the reasonable amount to get unit cell output. It is also found that the humidification gives the better performance result slightly.

• Bulletin of the Korean Chemical Society
• /
• 제8권6호
• /
• pp.462-465
• /
• 1987

The aggregation between cationic and anionic surfactants was studied by turbidimetric and nephelometric methods with emphasis on facile analysis of the surfactants and understanding of the mixed micellization. The turbidimetric titration of sodium dodecylsulfate (SDS) with cetyltrimethylammonium bromide (CTAB) or cetylpyridinium bromide (CPB) showed maximum turbidity at equimolar composition in the SDS concentration range of 0.1-0.9 mM. The nephelometric titration of the same systems extended the limit of analysis to 0.001 mM. The sodium salts of decylsulfate and sulfonate gave similar maxima, but not at equimolar composition. The coexistence of equimolar aggregates and mixed micelles were shown over broad composition range. The aggregation and mixed micellization of the anionic/cationic surfactants mixtures depended sensitively on the hydrophobic character of the surfactants.

• Bulletin of the Korean Chemical Society
• /
• 제18권1호
• /
• pp.38-43
• /
• 1997

Poly(ethylene 2, 6-naphthalate-co-tetramethylene 2, 6-naphthalate) (PEN/PBN) copolymers were synthesized and studied by 13C NMR spectroscopy, DSC analysis and X-ray diffraction. A minimum in the melting point vs. composition curve was found at approximately 60 mol% tetramethylene 2, 6-naphthalate. The PEN/PBN copolymers were shown to be statistically random throughout the range of 1, 4-butanediol compositions. The melting point depression behavior of annealed PEN/PBN copolymers depended upon the sequence propagation probability, PS, which is suggested by indivisual crystal formation of two pure comonomers; that is, ethylene-naphthalate-ethylene, EE, and tetramethylene-naphthalate-tetramethylene, BB. However, it can be seen from the X-ray curve that the peaks of PEN/PBN copolymers appear from a crystal lattice which is governed only by the rich component between two different aliphatic units in the copolymer composition.

• 농업생명과학연구
• /
• 제51권4호
• /
• pp.111-119
• /
• 2017

본 연구의 목적은 한우 도체형질과 등심에 대한 일반성분(수분, 조지방, 조단백질, 조회분) 분석을 통한 등심의 영양학적 가치와 유전모수 추정을 통한 개량형질 적용 가능성을 확인하기 위하여 실시하였다. 본 연구에 이용된 공시 재료는 한우 후대검정우 47차부터 57차까지 실시한 2,033두에 대하여 등심 1kg을 시료를 채취하여 분석한 자료를 이용하였다. 연구결과 한우 도체형질인 도체중, 등심단면적, 등 지방두께, 근내지방도에 대한 유전력은 각각 0.37, 0.51, 0.44, 0.57로 추정되었으며, 일반성분 분석인 수분, 조지방, 조단백질, 조회분에 대한 유전력은 각각 0.62, 0.64, 0.58, 0.12로 추정되었다. 그리고, 도체형질과 일반성분간의 유전상관은 도체중과 조지방에서 0.35, 근내지방도와 수분, 조지방, 조단백질, 조회분에서 각각 -0.966, 0.964, -0.924, -0.664으로 고도의 유전상관을 보였다. 수분과 조지방, 조단백질간의 유전상관은 각각 -0.998, 0.969로 분석되었으며, 조지방과 조단백질에서 -0.979로 고도의 유전상관을 보였다. 일반성분 분석치인 수분, 조지방, 조단백질에서 고도의 유전력을 보였으므로, 개량형질 이용 가능성이 있을 것으로 사료된다.

• International Journal of Safety
• /
• 제8권1호
• /
• pp.6-9
• /
• 2009

The crack in a J85 engine V.G. actuator arm shaft for a bell crank on the engine compressor was investigated. The crack was observed in twenty two shafts during the inspection of 238 shafts. The failure analysis of shaft cracks was performed by chemical composition analysis using ICP(Inductively Coupled Plasma) and by fracture surface and microstructure analysis using FE-SEM and optical microscope. The crack initiated from the top and bottom and propagated to the center along the grain boundaries. From the chemical composition analysis, the fractography of the fracture surface and the microstructure, it was found that the failure mechanism of the shafts is the inclusion-related intergranular decohesion crack. The inclusion was found out from MnS particle by EDS(Energy Dispersive Spectroscopy). The crack initiated MnS inclusion in the grain boundary and propagated with the increase of applied shear stress during long operation. In order to prevent the fracture, NDI(Nondestructive inspection) is needed periodically as recommended.

• 한국기계가공학회지
• /
• 제11권5호
• /
• pp.129-136
• /
• 2012

On this study, $CO_2$ gas, net of Ar gas, and mixed gas in solid wire(AWS ER 70S-6) and flux cored wire(AWS E71T-1) were used to weld on Mild steel(SS400). After the progress, the status changes of the welds in Mild steel(SS400) were investigated with compositional changes. For stable experiments, welding was conducted using the automatic feeder. Radiation testing, hardness testing, chemical composition analysis and penetrated cross-section were measured. Through these experiments, shapes of penetrated cross-section, chemical composition changes, and weld defects according to the variation of welding gas were known. Weld defects and weld cross-sectional shapes by the variation of the welding voltage were also detected.

• Journal of Life Science
• /
• 제11권1호
• /
• pp.27-29
• /
• 2001

Vibrio vulnificus endotoxin was extracted, analyzed the chemical composition, tested its biological activity, and compared to those of Escherichia coli and Salmonella typhimurium. The major fatty acid of three endotoxins were different each other; V. vulnificus endotoxins were different each other; V. vulnificus endotoxin was myristric acid (C14:0), E. coli was lauric acid (C12:0), S. typhimurium was capric acid (C10:0). The biological activities of V. vulnificus endotoxin were similar to those of E. coli and S. typhimurium in terms of the gelation activity of the Limulus amebocyte lysate and the lethal toxicity. But the result of enzyme (AST, ALT, and LDH) analysis showed that the enzyme activity of V. vulnificus endotoxin was similar to that of E. coli, but smaller than that of S. typimurium.