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Bio-based chiral dopants having an isohexide skeleton for cholesteric liquid crystal materials
Shin, Seunghan,Seo, Jae Won,Cho, Jin Ku,Kim, Sangyong,Cha, Jaeryung,Gong, Myoung Seon The Royal Society of Chemistry 2012 Green chemistry Vol.14 No.4
<P>Chiral dopants were synthesized from bio-based epimeric isohexides (glucose-derived isosorbide and mannose-derived isomannide) and their phase transition behaviors and abilities for developing cholesteric liquid crystal (CLC) films were examined with a consideration of the core structure. In spite of lower reactivity of the <I>endo</I> hydroxy group of isomannide caused by the steric hindrance and intermolecular hydrogen bonding, final synthetic yields of chiral dopants bearing an isomannide core (64.5% for IH-2 and 65.0% for IH-4) did not show conspicuous difference compared with chiral dopants bearing isosorbide (68.4% for IH-1 and 74.0% for IH-3). On the other hand, in phase transition behaviors, chiral dopants bearing an isomannide core showed lower crystalline and melting temperatures than IH-1, IH-3 despite of the same substituents. The helical twisting power (HTP) of chiral dopants bearing isosorbide (IH-1 and IH-3) was higher than that of chiral dopants bearing isomannide (IH-2 and IH-4). The calculated HTPs of IH-1 and IH-3 were 26.6 and 42.1 μm<SUP>−1</SUP>, respectively. In the case of IH-3, the helical pitch length of CLC could be adjusted to reflect visible light by controlling its amount and showed best performance in the range 5.0 to 7.0 mol%. In contrast to IH-1 and IH-3, it was found that IH-2 and IH-4 could not induce CLC films that reflect visible light.</P> <P>Graphic Abstract</P><P>Chiral dopants were synthesized from bio-based isohexides and applied to cholesteric liquid crystal materials. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2gc16261j'> </P>
Shin, Woo-Shik,Lee, Dohoon,Lee, Sang Joung,Chun, Gie-Taek,Choi, Si-Sun,Kim, Eung-Soo,Kim, Sangyong Elsevier 2018 Biochemical and biophysical research communication Vol.499 No.2
<P><B>Abstract</B></P> <P>Cis,<I>cis</I>-muconic acid (CCM) is a biochemical material that can be used for the production of various plastics and polymers and is particularly gaining attention as an adipic acid precursor for the synthesis of nylon-6,6. In the current study, the production of CCM was first attempted by introducing a newly developed protocatechuate (PCA) decarboxylase from <I>Corynebacterium glutamicum</I> 13032 to inha103, which completed the biosynthetic pathway therein. To improve CCM productivity, a phosphoenol pyruvate (PEP)-dependent phosphotransferase system (PTS) that consumed the existing glucose was developed, in the form of a strain with a non-PTS that did not consume PEP. To improve glucose uptake, we developed P25 strain, in which <I>iolR</I> (a transcriptional regulator gene) was additionally deleted. Strain P28, a P25 derivative expressing PCA decarboxylase, produced 4.01 g/L of CCM, which was 14% more than that produced by the parental strain. Moreover, strains P29 and P30, with an active pentose phosphate pathway and overexpressing important genes (<I>qsuB</I>) in the metabolic pathway, produced 4.36 and 4.5 g/L of CCM, respectively. Particularly, the yield per glucose in strain P30 was similar to that of the fed-batch culture of <I>Escherichia coli</I>, which has the highest reported yield of 22% (mol/mol). These results are underpinned by the characteristics of the non-PTS with increased PEP availability and a strain with deletion of the <I>iolR</I> gene, which greatly increased glucose uptake.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Engineered <I>C. glutamicum</I> produced CCM, valued for plastic and polymer production. </LI> <LI> The CCM yield from glucose in the optimized strain was about 22% (mol/mol). </LI> <LI> CCM productivity was enhanced by redirecting carbon flux in non-PTS <I>C. glutamicum</I>. </LI> </UL> </P>
김영철,신동범,이상용,양선석,강석모,류병우 한국경영과학회 1998 한국경영과학회 학술대회논문집 Vol.- No.1
본 연구에서는 대기업과의 협력관계에 있는 중소기업이 자사의 제품 정보를 관리하는 PDM시스템을 구축하기 위한 절차를 체계화하고, 제품 정보를 관리하기 위한 데이터베이스 설계를 위한 정보 수집 도구를 도출하였다. PDM시스템은 제조업체의 제품 정보를 관리하기 위한 정보시스템으로서, 각 제조업체의 업무 환경과 조직원들의 정보 이용 수준에 적합하게 구성되어야만 그 효과를 극대화 할 수 있다. 따라서 중소 제조업체에서 현업에서 사용되고 있는 제품 관련 정보를 체계적으로 수집하고 분석하여 업무 처리를 지원할 수 있는 정보시스템으로 구현하는 기술이 필요하다. 본 연구에서는 PDM시스템에서 관리되어야 할 정보 객체로서 부품, 도면/문서 등의 객체를 조사하고 이를 정보시스템을 통해서 데이터베이스화하기 위한 단계적 절차와 이 절차에서 조사되어야 할 정보 및 정보를 추출하기 위한 방법을 살펴보았다. 데이터베이스 구축을 위하여 객체지향적인 분석 방법을 적용하여 PDM시스템 구축을 위한 정보를 체계적으로 수집할 수 있는 질문서와 웍크시트를 개발하였다.
LZW 알고리즘의 초기 사전 확장을 통한 효과적인 Hyper - Text 문서 압축
신광철(Kwangcheol Shin),한상용(Sangyong Han) 한국정보과학회 2002 한국정보과학회 학술발표논문집 Vol.29 No.1A
LZW 알고리즘은 사전방식의 압축 알고리즘인 LZ78의 변형된 형태로써 높은 압축률을 제공하기 때문에 많은 압축 방법에서 사용되고 있다. LZW에서 사전을 이용하는 방식은 LZ78과는 달리 미리 문서에 나오는 문자들을(즉, ASCII 코드) 미리 저장해 놓고 압축을 한다. 본 논문은 Hyper-Text에서는 같은 단어가 자주 반복되는 것에 착안하여 그러한 단어를 코드형태로 미리 저장해 놓고 LZW알고리즘을 적용하였다. 본 논문에서 제시하는 방법의 성능을 테스트하기 위해 기존의 V.42bis에 이러한 확장된 초기사전을 적용한 후 기존의 V.42bis 및 UNIX의 compress에 비교하였다. 실험결과를 통해 기존의 V.42bis와 compress에 비해 각각 17.9%와 17.5%의 향상된 성능을 확인할 수 있다.
성대결절 음성 중증도에 따른 MDVP와 Praat 프로그램 별 파라미터 차이
심상용(Shim, SangYong),김향희(Kim, HyangHee),김재옥(Kim, JaeOck),신지철(Shin, JiCheol) 한국음성학회 2014 말소리와 음성과학 Vol.6 No.2
MDVP and Praat are measured by nine variables in common; F0, jitter local, jitter absolute, jitter relative average perturbation, jitter period perturbation quotient, shimmer local, shimmer dB, shimmer amplitude perturbation quotient, and NHR. In the present study, 30 female subjects were divided by their disorders(control group, vocal nodule group), ages(from 18 to 50 years old), gender(women), and severities of voice disorder(GRBAS-G0, G1, G2). Then, the subjects" vowel /a/ was evaluated by MDVP and Praat. First, jitter and shimmer variables of the MDVP were significantly different by severities. Praat showed different jitter, shimmer, and NHR parameters by severities. Second, jitter and NHR levels of MDVP were meaningfully higher than Praat regardless their severities. The result of the research confirms the relationships among GRBAS, MDVP and Praat as well as the differences in acoustic variables between MDVP and Praat.