• Computers and Concrete
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• 제12권1호
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• pp.53-64
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• 2013

The curing temperature is known to influence the rate of mechanical properties development of early age concrete. In realistic sites the temperature of concrete is not isothermal $20^{\circ}C$, so the paper measured adiabatic temperature increases of four different concretes to understand heat emission during hydration at early age. The temperature-matching curing schedule in accordance with adiabatic temperature increase is adopted to simulate the situation in real massive concrete. The specimens under temperature-matching curing are subjected to realistic temperature for first few days as well as adiabatic condition. The mechanical properties including compressive strength, splitting strength and modulus of elasticity of concretes cured under both temperature-matching curing and isothermal $20^{\circ}C$ curing are investigated. The results denote that comparing temperature-matching curing with isothermal $20^{\circ}C$ curing, the early age concretes mechanical properties are obviously improved, but the later mechanical properties of concretes with pure Portland and containing silica fume are decreased a little and still increased for concretes containing fly ash and slag. On this basement using an equivalent age approach evaluates mechanical properties of early age concrete in real structures, the model parameters are defined by the compressive strength test, and can predict the compressive strength, splitting strength and elasticity modulus through measuring or calculating by finite element method the concreted temperature at early age, and the method is valid, which is applied in a concrete wall for evaluation of crack risking.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.25-28
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• 2005

This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

• 한국염색가공학회지
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• 제32권3호
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• pp.150-157
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• 2020

Hexachloro-cyclophosphazene(HCCP), a formaldehyde-free flame retardant (FR), was steam-cured with triethanol amine(TEA) to impart durable flame-retardancy to cotton fabrics. While the HCCP treatment alone showed very limited resistance to repeated laundering cycles, the addition of TEA substantially improved the laundering durability of the FR cotton up to twenty laundering cycles. The extended washing resistance was accomplished by the increased nucleophilic substitution of unreacted P-Cl groups in HCCP by the TEA resulting in the more densely crosslinked FR networks. With increasing molar ratio of TEA to the HCCP up to 2, the flame retarding effectivity and the synergistic effectiveness improved to 2.8 and 1.8 respectively. TGA and microscale combustion calorimetry verified the pyrolysis and combustion behaviors of the FR-cotton, which showed lower maximum pyrolysis and combustion temperatures together with substantially decreased peak pyrolysis and heat release rate, synergistically yielding larger amounts of carbonaceous chars. The formaldehyde-free HCCP and TEA can be a durable FR finishing agents for cotton fabrics acting through a solid-phase flame-retarding mechanism.

• 국제초고층학회논문집
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• 제7권4호
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• pp.327-342
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• 2018

Geopolymer concrete (GPC), which is recognised as an environmentally friendly alternative to ordinary Portland cement (OPC) concrete, has been reported to possess high fire resistance. However, very limited research has been conducted to investigate the behaviour of geopolymer concrete-filled steel tubular (GCFST) columns at either ambient or elevated temperatures. This paper presents the compressive test results of a total of 15 circular concrete-filled steel tubular (CFST) stub columns, including 5 specimens tested at room temperature, 5 specimens tested at elevated temperatures and the remaining 5 specimens tested for residual strength after exposure to elevated temperatures. The main variables in the test program include: (a) concrete type; (b) concrete strength; and (c) curing condition of geopolymer concrete. The test results demonstrate that GCFST columns have similar ambient temperature behaviour compared with the conventional CFST counterparts. However, GCFST columns exhibit better fire resistance than the conventional CFST columns. Meanwhile, it is found that the GCFST column made with heat cured GPC has lower strength loss than other columns after exposure to elevated temperatures. The research results highlight the possibility of using geopolymer concrete to improve the fire resistance of CFST columns.

• 한국염색가공학회지
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• 제34권4호
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• pp.217-223
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• 2022

Flame-retardant finished silk fabrics could release carcinogenic formaldehyde resulting from the conventional finishing agents. New water-soluble cyclophosphazene derivative can be used as a formaldehyde-free flame retardant for the silk protein. Dichloro tetrakis{N-[3-dimethylamino)propyl]methacrylamido}cyclophosphazene(DCTDCP) can be cured by heat or UV irradiation as a durable flame retardant for the silk fabrics. Treatment conditions were optimized including curing temperature and time, finishing formulations, and UV energy. At the 30% DCTDCP application, peak HRR and THR decreased by 42.6% and 49.6% respectively compared to the pristine silk fabrics. Also char residue increased up to 48% from 11% indicating solid-phase retarding mechanism. The flame-retardant silk fabrics showed a LOI of 31.1 and the washed sample maintained a LOI of 26.8 even after ten laundering cycles.

• Advances in materials Research
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• 제11권2호
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• pp.165-170
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• 2022

Acrylic resin or polymethylmethacrylate (PMMA) is one of the most attractive materials to be used for dental appliances manufacturing. It has been introduced as a biomaterial during the last century. This study aims to evaluate the compounds absorption and release through acrylic resin to be used for drug delivery as well. The study specimens were 10 pieces of heat-cured clear acrylic resin with dimensions of 10 × 10 × 2 mm. The specimens were dipped in methylene blue solution at a powder-water ratio of 1:20 for 5 days. The samples were removed and dipped in 5 ml distilled water vials for 24 hours. Then the specimens were replaced into new 5 ml vials and the process lasted for 4 days. The extracted solutions were analyzed by the visible light spectroscopy for absorbance. The statistical results showed a gradual increase in stain release from day 1 to day 4 with a significant difference between day 1 and day 4 solutions. The study showed that PMMA resin is able to absorb and release some compounds constantly and the absorption drug-loading technique is applicable to this material.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.332-332
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• 2022

Ginseng has been traditionally used in Asia including Korea, for health care and to treat verities of different diseases such as immune disease, liver disease, and cancer. The current study was aim to unveal the most efficient method such heating, prethanol-A and ultrasound, for cured extraction of ginseng with higher antioxidant activity. The current results shows a significant improvement in the inhibition of H₂O₂ by the ultrasound method than the HT and Pre-A method. Thus this inhibition in free redical is possible through the increase in the antioxidant activity. Therefore in this study the CAT, APX and phenolic and flavonoid content was increased in ginseng seed and germinated ginseng sprouts by the US method, while the POD, SOD and GSH activity was increased in HT method. This suggest that the different extraction method in different stage of ginseng growth show a different biochemical and metabolites activation. Thereby the Ultrasound and Heat extraction was a feasible alternative method for extracting interested ingredients from biological materials.

• 대한소아치과학회지
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• 제26권2호
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• pp.296-309
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• 1999

가철성 상교정 장치에 많이 사용되는 자가중합형 상교정용 레진의 미반응 단량체는 레진의 물성과 생물학적인 면에 많은 영향을 끼친다. 따라서 미반응 단량체를 최소화하고 중합률을 최대로 하는 중합방법에 대한 연구는 중요한 의의를 갖는다. 저자는 자가중합형 상교정용 레진의 중합시간과 중합방법에 따른 중합률을 비교해보기 위해 시편을 다음과 같이 5군으로 나누어 연구를 진행하였다. 상교정용 레진의 분말과 용액을 혼합하여 제 1군은 $28^{\circ}C$의 공기중에 보관하였고, 제 2군은 $28^{\circ}C$의 물에, 제 3군은 $28^{\circ}C$의 물과 30psi의 압력에, 제 4군은 $43^{\circ}C$의 물에, 제 5군은 $43^{\circ}C$의 물과 30psi의 압력하에 각각 보관하였고, 10분, 1시간, 12시간, 1일, 3일 경과 후에 각 시편을 Fourier 변환적외선분광법을 이용하여 중합률을 측정하여 다음과 같은 결론을 얻었다. 1. 모든 군에서 중합시간이 경과함에 따라 중합률도 지속적으로 증가하는 양상을 보였다. 10분 경과 후의 결과와 비교하여 볼 때, 제 1군은 12시간 경과 후부터 중합률의 증가가 유의성이 있었고, 제 2군과 3군, 4군, 5군은 1시간 경과 후부터 유의성이 있었다(p<0.05). 2. 10분과 1일, 3일 경과 후에 제 5군, 제 4군, 제 3군, 제 2군, 제 1군의 순서대로 중합률이 높았다. 3. 중합시 온도에 따른 비교에서, 1일 경과 후를 제외하고는 모든 시간에서 $43^{\circ}C$에서 중합시킨 군의 중합률이 $28^{\circ}C$에서 중합시킨 군의 중합률 보다 유의성 있게 높았다(p<0.05). 4. 압력은 12시간 경과 후를(p<0.05) 제외하고는 중합률에 영향을 주지 못했다. 5. 보관방법은 1시간 경과 후를(p<0.05) 제외하고는 중합률에 영향을 주지 못했다.

• 대한한방내과학회지
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• 제37권6호
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• pp.961-977
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• 2016

Objectives: This study was designed to analyze the treatment effects of Eunhwayeongyo-tang through retrospective chart reviews. We also checked the correlation between each pair of variables of the symptoms and curative rates of patients with cough. Methods: Thirty-three patients with cough who had satisfied the selection criteria were retrospectively reviewed through their basic medical records, nasal endoscopy, and questionnaires about cough on their first and second visits. The questionnaires used were "The questionnaire on clinical symptoms of cough & sputum", Leicester Cough Questionnaire Korean Version (LCQ-K), Total Nasal Symptom Scores (TNSS), Visual Analog Scale (VAS), and "Cold-heat patterns". The improvement rate, calculated by "The questionnaire on clinical symptoms of cough & sputum" was considered to be clinically effective if reduction of symptoms scored more than 30%. The state of nasopharyngeal mucosa was assessed to categorize the cold-heat patterns of the upper respiratory tract and for diagnosis. Results: According to this study, cough and sputum improved by $57.22{\pm}37.76%$. Most patients (76%) improved significantly after $12.18{\pm}6.59days$ of taking Eunhwayeongyo-tang. The cure rates of 26 patients among the 33 patients were judged as effective. All the mean scores of the questionnaires and the anterior nasal cavity states were significantly improved on the patients' second visits. After $18.39{\pm}15.68days$, 30 patients were completely cured and ended treatment. The nasopharyngeal mucosa states of all patients were categorized as heat patterns. Conclusions: The conditions of the patients with nasopharyngitis significantly improved after taking Eunhwayeongyo-tang. All of the patients had pharyngitis or rhinitis. The cold-heat pattern of nasopharyngeal mucosa was a significant indicator of upper respiratory inflammation diagnosis.

• 동의생리병리학회지
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• 제20권4호
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• pp.793-798
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• 2006

Vertigo is one of the subjective symptoms which appears commonly in so many diseases that it is often neglected. But it needs active medical care because it can be a forewarning of serious illness like cerebral apoplexy. This thesis makes a study of vertigo in view of Hyungsang medicine. The followings are the conclusion drawn in diagnosis and treatment of Vertigo: Excess in the upper and deficiency in the lower part(上實下虛) is a main cause of male vertigo. Deficiency in the upper and excess in the lower part(下虛上實) is a general cause of female vertigo. Vertigo is also caused by the insufficiency of the kidney water(腎水) or reservoir of marrow(髓海). persons of Jung pe(精科) with large check bones , those of Fish type(魚類) with Dig mouth and thick lips ; and those with large heads are mainly attacked by this cause. A fleshy person's vertigo comes from the deficiency of Ki and damp phlegm(氣虛濕症) so it is cured by reinforcing Ki, removing dampness and dispelling phlegm. A slim person's vertigo comes from the deficiency of blood and dryness heat(血虛有火) so it is treated by tonifying the blood, cleaning heat away the heat. In case of womanly shaped male and manly shaped female, the vertigo is due to the phlegm fire. Wind-heat(風熱) can cause vertigo generally 施 the persons of following types : wind type(風人), running animal type(走類),bird type(烏類), and Yangmyung meridian type (陽明形). Vertigo also comes from consumption. The deficiency of Ki can be a cause of vertigo in case of male; persons with pale complexion; and those with pronounced noses. The deficiency of blood can be a reason of vertigo in the persons of Hyul type(血科) and those with pale eyelids and lips. The hypofunction of the splean and stomach brings on the deficiency of Ki and blood, which can give rise to the vertigo for those with large nose and mouth. The old people's vertigo comes from the hypofunction of Ki, blood, Yin and Yang.