• Computers and Concrete
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• 제20권2호
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• pp.165-176
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• 2017

Textile Reinforced Cementitious Composite (TRCC) became the most common construction material lately and have excellent properties. TRCC can be employed in the manufacture of thin-walled facade elements, load-bearing integrated formwork, tunnel linings or in the strengthening of existing structures. These composite materials are a combination of matrix and textile materials. There isn't much research done about the usage of polymer modified matrices in textile reinforced cementitious composites. In this study, matrix materials named as fine grained concretes ($d_{max}{\leq}1.0mm$) were investigated. Air entraining effect of polymer modifiers were analyzed and air void content of fine grained concretes were identified with different methods. Aim of this research is to study the effect of polymer modification on the air content of fine grained concretes and the role of defoamer in controlling it. Polymer modifiers caused excessive air entrainment in all mixtures and defoamer material successfully lowered down the air content in all mixtures. Latex polymer modified mixtures had higher air content than redispersible powder modified ones. Air void analysis test was performed on selected mixtures. Air void parameters were compared with the values taken from air content meter. Close results were obtained with tests and air void analysis test found to be useful and applicable to fine grained concretes. Air void content in polymer modified matrix material used in TRCC found significant because of affecting mechanical and permeability parameters directly.

• 공업화학
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• 제7권2호
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• pp.334-340
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• 1996

석탄을 원료로 하는 탄화 시료로 분자체 특성을 지닌 탄소 흡착제를 제조하였다. 변형제를 사용하여 탄소 분자체를 만들었으며, 변형제 농도 변화에 따른 분자체 특성에 관해 연구하였다. 그리고 탄소 분자체의 성능을 측정키 위해 산소와 질소가스를 사용하였으며, Cahn microbalance(D-200)를 사용하여 탄소 흡착제의 흡착 속도를 측정하였다. 이 실험치를 흡착 속도식에 대입하여 탄소 분자체에 따른 가스의 확산도를 구하였으며, 분자체 성능에 대한 변형제 분자량과 농도의 영향을 나타내었다.

• 센서학회지
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• 제15권3호
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• pp.173-178
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• 2006

Silica aerogel with ultra low density and high porosity has been focused on versatile application due to its fascinating properties. Ambient drying process of waterglass, in this study was researched to fabricate a crack-free monolith body in the point view of cost effective way. Wet gel was obtained by removing of $Na^{+}$ ions in waterglass, which contains 8 wt% of $SiO_{2}$. Xylene, which has a low vapor pressure, was used as a solution substitutor to prevent the formation a cracks during drying. Various surface modifiers like as hexamethyldisilazane (HMDSZ), trimethylchlorosilane (TMCS), methyltriethoxylsilane (MTES), methyltrimethoxysilane (MTMS) and phenyltriethoxysilane (PTES) were used in order to improve hydrophobicity of the waterglass Silica aerogel. Some physical properties of the surface modified aerogels were investigated by FT-IR, TGA, BET and SEM. Hydrophobicity and hydrophilicity of Silica aerogel is attributed to the Si-OH bond and the non-polar C-H bond groups on the surface of aerogel. Crack-free waterglass aerogel with >90 % of porosity, 17 nm of pore size and <0.15 $g/cm^{3}$ of density was prepared. HMDSZ and TMCS are effective as a surface modifier

• 한국언어정보학회지:언어와정보
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• 제19권2호
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• pp.127-153
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• 2015

Negative expressions have their semantic function of classical negation as a pure reverser of truth-values. They also have various kin and foes of their pragmatic functions such as association of bad feelings (Russell 1948), emphasis/attenuation by negative polarity items, sarcasm, and metalinguistic negation (MN). This paper explores how MN and descriptive negation (DN) differ and whether the difference creates pragmatic ambiguity (Horn 1987) or reflects merely contextual variations of one logical negation (Carston 1996). To test the debate, this paper treats certain degree modifiers licensed exclusively by MN as in Mia-ka POTHONG/Yekan yeppu-n key an-i-a [external neg] (vs. modifier NPIs like cenhye 'at all', licensed only by DN) and contrasts them with bad utterances of the MN modifiers in [short form neg] sentences (not for MN) such as Mia-ka POTHONG an yeppu-e. The ERP results of the well-formed vs. ill-formed conditions evoked the N400 at Cz in written stimuli and the N400 near the center on both hemispheres in spoken stimuli. The results suggest that the anomalies are meaning-related and tend to support the pragmatic ambiguity.

• 한국세라믹학회지
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• 제33권4호
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• pp.385-390
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• 1996

The electrical resistivity of the ceramic glaze coated on ceramic substrate plays an important role on the characteristics of the thick and thin film electrical circuits. In this study the effects of the various modifiers on the electrical resistivity were examined in SiO2-Al2O3-B2O3-RO-Na2O (RO=CaO , SrO, BaO, PbO) glass system. In alkali free glasses where divalent cations are responsible for electrical conduction the electrical conductivity of th glasses increased with the ionic size of divalent cations due to the decrease in the bond strength between oxyben and divalent cation. In Na2O containing glasses however where Na+ ion is responsible for electrical conduction the ionic conductivity decreased with the ionic size of divalent cations because the blocking effect of the cations on Na+ ion movement increased with larger divalent cations. Na+ ionic conduction also depended on the glass structure relaxation due to the corrdination number changes of B2O3 and Al2O3 which varied with the NaO2 content in the glass.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.169-172
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• 2009

본 연구에서는 고연소속도 고체추진제 개발을 위한 현재의 기술들과 연구동향을 분석하였고, 연소속도 조절제에 대한 추진제 적용 및 연소 특성에 대해 검토하였다. 또한 연소속도 조절제로bis(ethylenediamine)copper perchlorate(BECP)를 제조하였고 이의 연소특성이 Butacene/AP 추진제에서 평가되었다. 결과적으로, Butacene과 AP로 구성된 고연소속도 고체 추진제에서 금속배위화합물인 BECP는 고체추진제의 연소속도를 크게 증진시켰다.

• Preventive Nutrition and Food Science
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• 제22권2호
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• pp.81-89
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• 2017

Healthy aging has become a major goal of public health. Many studies have provided evidence and theories to explain molecular mechanisms of the aging process. Recent studies suggest that epigenetic mechanisms are responsible for life span and the progression of aging. Epigenetics is a fascinating field of molecular biology, which studies heritable modifications of DNA and histones that regulate gene expression without altering the DNA sequence. DNA methylation is a major epigenetic mark that shows progressive changes during aging. Recent studies have investigated aging-related DNA methylation as a biomarker that predicts cellular age. Interestingly, growing evidence proposes that nutrients play a crucial role in the regulation of epigenetic modifiers. Because various nutrients and their metabolites function as substrates or cofactors for epigenetic modifiers, nutrition can modulate or reverse epigenetic marks in the genome as well as expression patterns. Here, we will review the results on aging-associated epigenetic modifications and the possible mechanisms by which nutrition, including nutrient availability and bioactive compounds, regulate epigenetic changes and affect aging physiology.

• 펄프종이기술
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• 제43권3호
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• pp.121-127
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• 2011

This study used two types of rheology modifiers including an alkali-swellable emulsion (ASE) and an surface-adhesion emulsion (SAE) to elucidate their effects on high shear viscosity and dynamic penetration behavior among the flow properties of high solids coating. Since rheology under high shear and dynamic penetration behavior significantly affect the quality of coated paper in case of high solids coating, it is very important to examine the variations in rheology of high solids coating color by rheology modifier. It was found that the high solids coating color prepared with the SAE type showed superior dynamic penetration behavior and high shear viscosity than that with the ASE type rheology modifier.

• 분석과학
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• 제8권4호
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• pp.435-442
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• 1995

A matrix modification was studied for the determination of trace bismuth in water samples by graphite furnace atomic absorption spectrophotometry. The type and quantity of modifiers as well as the use of auxiliary modifiers were investigated to realize the efficient modification. Palladium was chosen as a single modifier. By the addition of palladium($5{\mu}g/mL$) to 100 ng/mL bismuth solution, the temperatures could be raised from $500^{\circ}C$ to $1,300^{\circ}C$ for the charring and from $2,000^{\circ}C$ to $2,200^{\circ}C$ for the atomization as well as the sensitivity and reproducibility were improved. The absorbance of bismuth was maximum and not changed in the range of Pd $3-25{\mu}g/mL$. And several materials were examined as an auxiliary modifier. The mixed solution of $1{\mu}g/mL$ palladium and $200{\mu}g/mL$ nickel have raised the temperatures as with $5{\mu}g/mL$ palladium only. The maximum absorbance of bismuth was shown in the nickel concentration range of $100-300{\mu}g/mL$ in $1{\mu}g/mL$ palladium modified system. With such optimum conditions, the trace amount of bismuth in several water samples could be determined by a calibration curve method, and good recoveries were also obtained.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2008년도 추계학술대회
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• pp.90-93
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• 2008

In natural language, it is common that repetitive constituents in an expression are to be left out and it is necessary to figure out the constituents omitted at analyzing the meaning of the sentence. This paper is on recognition of boundaries of parallel noun phrases by figuring out constituents omitted. Recognition of parallel noun phrases can greatly reduce complexity at the phase of sentence parsing. Moreover, in natural language information retrieval, recognition of noun with modifiers can play an important role in making indexes. We propose an unsupervised probabilistic model that identifies parallel cores as well as boundaries of parallel noun phrases conjoined by a conjunctive particle. It is based on the idea of swapping constituents, utilizing symmetry (two or more identical constituents are repeated) and reversibility (the order of constituents is changeable) in parallel structure. Semantic features of the modifiers around parallel noun phrase, are also used the probabilistic swapping model. The model is language-independent and in this paper presented on parallel noun phrases in Korean language. Experiment shows that our probabilistic model outperforms symmetry-based model and supervised machine learning based approaches.