• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1810-1818
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• 2015

For the synthesis of various pharmaceuticals, chiral alcohols are useful intermediates. Among them, (R)-ethyl-4-chloro-3-hydroxybutanoate ((R)-ECHB) is an important building block for the synthesis of L-carnitine. (R)-ECHB is produced from ethyl-4-chloro-3-oxobutanoate (ECOB) by a reductase-mediated, enantioselective reduction reaction. The Saccharomyces cerevisiae YOL151W reductase that is expressed in Escherichia coli cells exhibited an enantioselective reduction reaction toward ECOB. By virtue of the C-terminal His-tag, the YOL151W reductase was purified from the cell-free extract using Ni²⁺-NTA column chromatography and immobilized onto Ni²⁺-magnetic microparticles. The physical properties of the immobilized reductase (Imm-Red) were measured using electron microscopy, a magnetic property measurement system, and a zeta potential system; the average size of the particles was approximately 1 μm and the saturated magnetic value was 31.76 emu/g. A neodymium magnet was used to recover the immobilized enzyme within 2 min. The Imm-Red showed an optimum temperature at 45℃ and an optimum pH at 6.0. In addition, Bacillus megaterium glucose dehydrogenase (GDH) was produced in the E. coli cells and was used in the coupling reaction to regenerate the NADPH cofactor. The reduction/oxidation coupling reaction composed of the Imm-Red and GDH converted 20 mM ECOB exclusively into (R)-ECHB with an e.e._p value of 98%.

• 한국재료학회지
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• 제15권11호
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• pp.717-721
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• 2005

Silica powders were synthesized using emulsion solution containing water, nonionic surfactant of Triton N-57, and cyclohexane. Silica powders were prepared at low cost using inexpensive starting material of sodium silicate and ammonium sulfate. Morphology, size and size distribution were observed and determined using SEM. The powder was identified as silica by FT-IR and XRD analysis. Particle size and size distributions were affected by concentration of reactants, reaction time, and concentration of surfactant. Particle size were increased with increasing concentration of reactants and particles became dense with increasing reaction time. As R value increased, tile particle size was increased, reached a certain value and then decreased again. The silica powders synthesized under optimum condition were spherical in shape, $0.8{\mu}m$ in average particle size, narrow in particles size distribution, and well dispersed.

• 미생물학회지
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• 제19권2호
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• pp.63-77
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• 1981

The growth rate of yeast population (Saccharomyces uvarum) cultivated in the Knopp's modified medium (plus various carbon sources) appeared the highest value when the Knopp's minimal medium was treated to 1.5% with disaccharide such as maltose and sucrose. Also the treatment of lactose and raffinose resulted in polulation growth as to the population size in case of maltose and sucrose. However, the gorwth of yeast was not occurred at all when a polysaccharide, such as inulin, was added as carbon source. The growth from of yeast population in Knopp's modified medium are characterized by the fact that log phase continued 100hrs after inoculation and that stationary state phase appeared in general 250hrs after inoculation. Applying the various carbon sources to respiration substrate for yeast cell, the respiration rate of yeast showed the highest value in treatment of maltose and followed in order of raffinose, lactose, glucose, and sucrose. Determined the amount of poly-phosphate and turn over pathway of poly-phosphate according to culture phase of yeast, it is revealed that the yeast synthesized 3 types of poly phosphate (poly-P A,B, and C) and postulated that turn over pathway of poly-phosphate as follows ; Inorganic phosphate is converted into each kind of polyphosphates, and then one part of poly-P-C is converted into poly-P-B, the rest poly-p-C and poly-P-B are converted into poly-P-A. The synthesized poly-phosphate is considered to have a role as energy pool utilizing to synthesis of cellular organic materials. Of the 13 carbon sources used in this experiment, the useful carbon sources for biosynthesis of poly-phosphate and cellular organic materials are confirmed as disaccharide (maltose and sucrose) as well as glucose. Protein synthesis in yeast cell showed the two peaks on 6th and 8th day after inoculation ; nucleic acid on 2nd day (48hrs), carbohydrates on 2nd day (48hrs), and phospholipid on 2nd and 8th day after inoculation, respectively.

• 한국멀티미디어학회논문지
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• 제9권7호
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• pp.801-807
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• 2006

본 연구는 국악기 피리의 소리합성을 위한 기초 단계로, 피리의 음색 특징을 분석하였다 분석은 세 가지로 나누어 첫째, 피리의 음색 특징을 스펙트럼 분석을 통하여 오보에와 비교하였고, 둘째, 피리 소리들의 어택(attack)부분의 시간대별 분석을 통하여 소리 발생과정에 따른 음색을 분석하였으며, 마지막으로 악기연주의 중요한 역할을 하는 비브라토의 특성을 분석해 보았다. 그 결과 피리 음색은 서양악기와 달리 높은 배음들의 음량이 높게 나타났고, 소리발생 초기단계(어택 부분)에서는 노이즈 양이 급격히 줄어드는 것과 반하여 배음들의 음량 값이 높아졌으며, 비브라토에서도 음량위주로 변화하는 서양악기와 달리 음고와 음량이 동시에 변화한다는 특성을 알 수 있었다. 이러한 배음에 따른 음색 특징과 소리 발생과정에서의 음색변화, 그리고 비브라토에서의 음고와 음량 변화는 피리의 독특한 음색을 잘 나타내 주는 특징들로써 소리합성에 있어서 반드시 적용되어져야 할 것이다.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.298-298
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• 2006

There has been much interest in incorporating nanoscale voids into dielectric materials in order to reduce their k value, and thus in producing low-k porous interdielectric materials. One approach to the development of low-k dielectric materials is the templated polycondensation of organosilicate precursors in the presence of a thermally labile, organic polymeric porogen. The other is SiOCH films have low dielectric constant as well as good mechanical strength and high thermal stability through PECVD. In this article we explore the nanopore generation mechanism of organosilicate film using star-shape porogen and SiOCH film using bis-trimethylsilylmethane (BTMSM) precursor.

• 한국재료학회지
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• 제14권5호
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• pp.305-309
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• 2004

Mechanical alloying (MA) of Ti-25.0～37.5at%Si powders was carried out in a high-energy ball mill, and in situ thermal analysis was also made during MA. In order to classify the synthesis behavior of the powders with respect to at%Si, the synthesis behavior during MA was investigated by in situ thermal analysis and X-ray diffraction (XRD). In situ thermal analysis curves and XRD patterns of Ti-25.0～26.1at%Si powders showed that there were no peaks during MA, indicating $Ti_{5}$ $Si_3$ was synthesised by a slow reaction of solid state diffusion. Those of Ti-27.1～37.5at%Si powders, however, showed that there were exothermic peaks during MA, indicating $_Ti{5}$ $Si_3$ and$ Ti_3$Si phase formation by a rapid exothermic reaction of self-propagating high-temperature synthesis (SHS). For Ti-27.1～37.5at%Si powders, the critical milling times for SHS decreased from 38.1 to 18.5 min and the temperature rise, ΔT (= peak temperature - onset temperature) increased form $19.5^{\circ}C$ to $26.7^{\circ}C$ as at%Si increased. The critical composition of Si for SHS reaction was found to be 27.1at% and the critical value of the negative heat of formation of Ti-27.1at%Si to be -1.32 kJ/g.

• 한국재료학회지
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• 제14권5호
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• pp.310-314
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• 2004

Mechanical alloying (MA) of Ti-50.0～66.7at%Si powders was carried out in a high-energy ball mill, and in situ thermal analysis was also made during MA. In order to classify the synthesis behavior of the powders with respect to at%Si, the synthesis behavior during MA was investigated by in situ thermal analysis and X-ray diffraction (XRD). In situ thermal analysis curves and XRD patterns of Ti-50.0～59.6at%Si powders showed that there were exothermic peaks during MA, indicating TiSi, $TiS_2$, and $Ti_{5}$ $Si_4$ phase formation by a rapid exothermic reaction of self-propagating high-temperature synthesis (SHS). Those of Ti-59.8～66.7 at%Si powders, however, showed that there were no peaks during MA, indicating any Ti silicide was not synthesised until MA 240 min. For Ti-50.0～59.6at%Si powders, the critical milling times for SHS increased from 34.5 min to 89.5 min and the temperature rise, $\Delta$T (=peak temperature-onset temperature) decreased form $26.2^{\circ}C$ to $17.1^{\circ}C$ as at%Si increased. The critical composition of Si for SHS reaction was found to be 59.6at% and the critical value of the negative heat of formation of Ti-59.6at%Si to be -1.48 kJ/g.

• 미생물학회지
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• 제7권1호
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• pp.10-21
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• 1969

The effect of glucose and 2-thiobarbituric acid on the biosynthesis of cell constituents such as protein, carbohydrate, DNA, RNA, phospholipid and PCA-soluble phosphate compounds in Chlorella duing the life cycle was measured, and the changes in the content of these main cellular components of the algal cell were analyzed in connection with the nuclear and cytoplasmic divison. In the normal autotrophic synchronous culture the contents of protein, RNA, and DNA in the cell showed a chracteristic changes according to the progress of cell development, increasing more or less throughout all the life cycle. The synthesis of protein is more prominent in the division period nad that of DNA is more active in the ripening period, while the synthesis of RNA is more rapid in the growing and ripening periods than other developmental stages. The period of division cycle was little affected by glucose in the medium, although the synchrony of the growth and cellular division was disturbed and the n value increased. The cotents of protein, carbohydrate, RNA nad DNA of the cell were increased by the glucose treatment throughout all the life cycle. On the other hand, both of cellular growth and division were retarded severely and the n value was decreased by the 2-thiobarbituric acid treatment throughout all the life cycle. On the other hand, both of cellular growth and division were retarded severely and the n value was decreased by the 2-thiobarbituric acid treatment. The synthesis of protein, carbohydrate, DNA, RNA and phospholipid of the cell was also retarded by 2-thiobarbituric acid. In the autotrophic, mixotrophic and 2-thiobarbituric acid-treated cultures, each having different mode cytoplasmic division, a common general schema occurring in the cell during the life cycle may be drawn as follows. The ratio of RNA to protein attains maximum value in the $L_1$-cell stage prior to the nuclear division and thereafter decreases during the periods of ripening and division. The ratio of PCA-soluble phosphate compounds to protein increased from the begining of the culture to $L_4$-cell stage successively and thereafter decreased gradually during the division period, while the ratio of protein to DNA kept almost constant up to the division period and thereafter increased during the division period. Therefore, it is presumed that the increase in the ratio of RNA to protein is to be an inducer of nuclear division and that the cytoplasmic division is induced by the increase in the ratio of protein to DNA.

• Asian-Australasian Journal of Animal Sciences
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• 제2권4호
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• pp.615-623
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• 1989

Three sheep fitted with rumen cannulae and abomasal cannulae were given daily 750 g (DM) of three diets consisting of straw-manure silage and barley mixture in the ratios of 75:25, 50:50 and 25:75. As the proportion of barley in the diet increased, there was an increase in the amount of OM apparently digested in the rumen and thole tract (P<.01). But ADF digestion was decreased. For the 25:75 diet the $NH_3-N$ content in the rumen showed the highest value, but the total VFA was the lowest. The rumen volume and dilution rate increased with increasing ratio of silage in diets. There were no significant differences between diets in abomasal NAN flow, and the bacterial-N for the 25:75 diet was 7.3 g N as compared with 9.2-9.6 g N for the other diets (P<.01). Rates of bacterial nitrogen synthesis in the rumen were 30.5, 24.1 and 14.9 g N per Kg OM apparently digested in the rumen for the 75:25, 50:50 and 25:75 diets, respectively.

• 말소리와 음성과학
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• 제10권1호
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• pp.39-48
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• 2018

A typical statistical parametric speech synthesis (text-to-speech, TTS) system consists of separate modules, such as a text analysis module, an acoustic modeling module, and a speech synthesis module. This causes two problems: 1) expert knowledge of each module is required, and 2) errors generated in each module accumulate passing through each module. An end-to-end TTS system could avoid such problems by synthesizing voice signals directly from an input string. In this study, we implemented an end-to-end Korean TTS system using Google's Tacotron, which is an end-to-end TTS system based on a sequence-to-sequence model with attention mechanism. We used 4392 utterances spoken by a Korean female speaker, an amount that corresponds to 37% of the dataset Google used for training Tacotron. Our system obtained mean opinion score (MOS) 2.98 and degradation mean opinion score (DMOS) 3.25. We will discuss the factors which affected training of the system. Experiments demonstrate that the post-processing network needs to be designed considering output language and input characters and that according to the amount of training data, the maximum value of n for n-grams modeled by the encoder should be small enough.