Effect of Network Polymerization on the Pressure-Induced Structural Changes in Sodium Aluminosilicate Glasses and Melts: ²⁷Al and ¹⁷O Solid-State NMR Study

Lee, Sung Keun,Yi, Yoo Soo,Cody, George D.,Mibe, Kenji,Fei, Yingwei,Mysen, Bjorn O. American Chemical Society 2012 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.116 No.3

<P>Probing the pressure-induced structural changes and the extent of disorder in aluminosilicate glasses and melts at high pressure remains a challenge in modern physical and chemical sciences. With an aim of establishing a systematic relationship between pressure, composition, and glass structures, we report <SUP>27</SUP>Al and <SUP>17</SUP>O 3QMAS NMR spectra for sodium aluminosilicate glasses [Na<SUB>2</SUB>O:Al<SUB>2</SUB>O<SUB>3</SUB>:SiO<SUB>2</SUB> = 1.5:0.5:2<I>n</I> with <I>n</I> = 1 (NAS150520, <I>X</I><SUB>SiO2</SUB> = 0.5), 2 (NAS150540, <I>X</I><SUB>SiO2</SUB> = 0.67), and 3 (NAS150560, <I>X</I><SUB>SiO2</SUB> = 0.75)], quenched from melts at pressures up to 8 GPa. We also explore the stability of the <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al cluster in the highly depolymerized, NAS150520, glass at high pressure. For given glass composition, the <SUP>[5,6]</SUP>Al peak intensity increases with increasing pressure. The population of <SUP>[5,6]</SUP>Al increases linearly with <I>X</I><SUB>SiO2</SUB> from NAS150520 (<I>X</I><SUB>SiO2</SUB> = 0.5) to NAS150560 glass (<I>X</I><SUB>SiO2</SUB> = 0.75) at both 6 and 8 GPa. The <SUP>[5,6]</SUP>Al/<I>X</I><SUB>SiO2</SUB> ratio also tends to increase with pressure, indicating a possible relationship between <SUP>[5,6]</SUP>Al fraction and <I>X</I><SUB>SiO2</SUB> that depends on pressure. The effect of pressure on the network connectivity in the sodium aluminosilicate glasses is manifested in the increase in <SUP>[4]</SUP>Si–O–<SUP>[5,6]</SUP>Al peak intensity and the decrease in the nonbridging oxygen (NBO) fraction with increasing pressure. The fraction of <SUP>[4]</SUP>Si–O–<SUP>[5,6]</SUP>Al in NAS150520 is smaller than in NAS150560. Taking into consideration the pressure-induced Al coordination transformation in the fully polymerized glass (albite, Na<SUB>2</SUB>O:Al<SUB>2</SUB>O<SUB>3</SUB>:SiO<SUB>2</SUB>= 1:1:6, NBO/T = 0), the fraction of <SUP>[5,6]</SUP>Al at a given pressure varies <I>nonlinearly</I> with variations of NBO/T. <SUP>[5,6]</SUP>Al fraction at 8 GPa increases with decreasing degree of melt polymerization from ∼8% for fully polymerized albite melt (NBO/T = 0) to ∼37% for partially depolymerized melt (NAS150560, at NBO/T = 0.29). Then it gradually decreases to ∼15% for NAS150520 with further increase in NBO/T of 0.67. This observed trend in the densification behavior at a given pressure indicates competing densification mechanisms involving steric hindrance vs changes of NBO fraction in the silicate melts. The NMR results also suggest that both NBO and BO, particularly <SUP>[4]</SUP>Si–O–<SUP>[4]</SUP>Si, interact with Na<SUP>+</SUP>, and thus the Na<SUP>+</SUP> distribution is likely to be homogeneous around both NBO and BO at high pressure without spatial segregation of silica-rich and alkali-rich domains for the glass compositions studied here. The presence of the <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al cluster is distinct in the NMR spectrum for NAS150520 glass at both 6 and 8 GPa. A new scheme of pressure-induced structural transitions in silicate melts involving <SUP>[4]</SUP>Al–O–<SUP>[4]</SUP>Al includes the formation of <SUP>[4]</SUP>Al–O–<SUP>[5]</SUP>Al.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-3/jp206765s/production/images/medium/jp-2011-06765s_0008.gif'></P>

A conserved splicing silencer dynamically regulates O-GlcNAc transferase intron retention and O-GlcNAc homeostasis

Sung-Kyun Park,Xiaorong Zhou,Kathryn E. Pendleton,Olga V. Hunter,Jennifer J. Kohler,Kathryn A. O’Donnell,Nicholas K. Conrad 한국당과학회 2018 한국당과학회 학술대회 Vol.2018 No.01

Modification of nucleocytoplasmic proteins with O-GlcNAc regulates a wide variety of cellular processes and has been linked to human diseases. The enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) add and remove O-GlcNAc, but the mechanisms regulating their expression remain unclear. Here, we demonstrate that retention of the fourth intron of OGT is regulated in response to O-GlcNAc levels. We further define a conserved intronic splicing silencer (ISS) that is necessary for OGT intron retention. Deletion of the ISS in colon cancer cells leads to increases in OGT, but O-GlcNAc homeostasis is maintained by concomitant increases in OGA protein. However, the ISS-deleted cells are hypersensitive to OGA inhibition in culture and in soft agar. Moreover, growth of xenograft tumors from ISS-deleted cells is compromised in mice treated with an OGA inhibitor. Thus, ISS-mediated regulation of OGT intron retention is a key component in OGT expression and maintaining O-GlcNAc homeostasis.

광탄성실험 Hybrid 법에 의한 일정한 변형율을 받는 O-Ring 의 응력해석

권오성(O-Sung Kwon),황재석(Jai-Sug Hawong),남정환(Jeong-Hwan Nam),한송령(Song-Ling Han),박성한(Sung-Han Park) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

In this research, stresses of O-ring with uniform deformation ratio in upper and lower direction are analyzed by photoelastic experimental hybrid method. The O-ring is made from rubber and is used to sealing of the high pressure vessel. The compressive deformation ratios of O-ring are 10% and 20%. Stress components (σ<SUB>xx</SUB>, σ<SUB>yy</SUB>, τ<SUB>xy</SUB>) of O-ring uniform ratios obtained from the photoelastic experimental hybrid method are almost identical to those from Hertz’s theory. Therefore, stress freezing method and photoelastic experimental hybrid method are effective applied to the stress analysis of O-ring made from rubber and with uniform ratios. The loading device developed in this research is used to produce the uniform deformation ratio of O-ring and as loading device of stress freezing. Stress distributions results from the upper contact surface of O-ring are almost identical to those from the lower contact surface of O-ring without regard to squeeze deformation ratio.

장기 저장연료의 열안정성 및 연료접촉 고무오링의 수명예측 연구

정근우(K. W. Chung),홍진숙(J. S. Hong),김영운(Y. W. Kim),한정식(J. S. Han),정병훈(B. H. Jeong),권태수(T. S. Kwon),서동욱(D. O. Suh),성민준(M. J. Sung),권영일(Y. I. Kwon) 한국트라이볼로지학회 2018 한국윤활학회지(윤활학회지) Vol.34 No.5

Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

CHF₃ / C₂F6 플라즈마에 의한 실리콘 표면 잔류막의 특성

권광호(K.-H. Kwon),박형호(H.-H. Park),이수민(S. M. Lee),강성준(S. J. Kang),권오준(O.-J. Kwon),김보우(B.W. Kim),성영권(Y.-K. Sung) 한국진공학회(ASCT) 1992 Applied Science and Convergence Technology Vol.1 No.1

실리콘을 CHF₃/C₂F_6 가스 플라즈마를 이용하여 식각하면 실리콘위에 탄소, 불소 및 산소로 이루어진 잔류막이 형성된다. 이 잔류막을 XPS로 분석한 결과 탄소는 C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, C-F₃ 결합을 하고 있으며, 불소는 F-Si, F-C 및 F-O 결합으로 이루어져 있음을 알았다. 한편 산소는 O-Si 및 O-F 결합으로, 실리콘은 Si-Si, Si-C 및 Si-O 결합상태를 나타낸다. 잔류막의 수직분포 연구를 통하여 Si-O 및 Si-C 결합이 탄소와 불소의 결합층 아래에 존재하고, 잔류막의 표면부에 F-O 결합이 분포함을 알았다. 또한 건식식각 변수가 잔류막 형성에 미치는 영향이 조사되었으며 CHF₃/C₂F_6 가스 유량비, RF power 벚 압력 등이 잔류막의 두께, 조성비 및 잔류막의 결합상태에 영향을 미침을 알 수 있었다. Si surfaces exposed to CHF₃/C₂F_6 gas plasmas in reactive ion etching (RIE) have been characterized by X-ray photoelectron spectroscopy (XPS). CHF₃/C₂F_6 gas plasma exposure of Si surface leads to the deposition of residual film containing carbon and fluorine. The narrow scan spectra of C 1s show various bonding states of carbon as C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, and C-F₃. The chemical bonding states of fluorine are described with F-Si, F-C, and F-O. And the oxygen and silicon are also detected. The effects of parameters for reactive ion etching as CHF₃/C₂F_6 gas ratio, RF power, and pressure are investigated.

Photopolymer의 홀로그램 기록특성

성기영,최옥식,경천수,곽종훈 嶺南大學校 基礎科學硏究所 1997 基礎科學硏究 Vol.17 No.-

We fabricated photopolymer hologram and explained hologram formation processes. Dynamic self-diffraction oscillation of photopolymer is observed by two wave mixing experiment and it is well explained by the modified Kogelnik's coupled wave equation.

XML 프로토콜을 지원하는 웹기반 SPC 시스템

오경제,서양진,김성일,한상용 중앙대학교정보통신연구소 2000 정보통신연구소논문집 Vol.2 No.1

경쟁적인 시장에서 살아남기 위해서는 공장의 공정제어를 정확하게 하는 것이 필수적이다. SPC(Statistical Process Control) 시스템을 품질 향상의 욕구를 충족시키기 위해 광범위하게 운영되며, 다른 툴과의 접목에 어려움이 있다. 본 논문이 제안하는 SPC 시스템은 웹을 기반으로 하고, XML을 입력/출력 프로토콜로 이용한다. 또한 강력한 그래픽 표현기능과 효율적인 파일 시스템으로 실시간 제어를 가능하게 한다. 새로운 SPC 시스템은 어떤생산체제에도 사용 가능하지만, 특히 반도체, TFT/LCD 산업에 최적화되어 있다. 시스템의 구현은 C++과 COM/DCOM을 사용하며, 기존의 제품보다 향상된 성능을 보인다. Accurate process control in the manufacturing industry is essential to survive in the competitive market. Statistical process control(SPC) system has been widely used to satisfy the ever-increasing quality control requirements. However, most commercial products in the market are not flexible, semi-automatic, and difficult to interface with other tools. In this paper, we propose an advanced SPC system which is based on the web and supports XML protocol. We also provide a powerful graphic facility and an efficient file system to handle the data in real time. Even though the idea can be applied to any manufacturing system, our system is optimized to the semi-conductor industry and TFT/LCD industry. The system is implemented in C++ and COM/DCOM, and shows a good result.

개혁개방과 중국 조선족 소설문학 : 90년대 상반기 소설문학을 중심으로

오상순 효성여자대학교 한국전통문화연구소 1997 韓國傳統文化硏究 Vol.12 No.-

불만표시 발화행위 : 독일인과 한국인의 상호문화 비교 A Cross-Cultural comparison between Germans and Koreans

오상이 경북대학교 사범대학 부속 중등교육연구소 2005 중등교육연구 Vol.53 No.2

본 연구에서는 모국어 화자인 독일인과 한국인, 그리고 독일에 사는 비모국어 화자인 한국인이 <소음 공해에 대한 불만표시>의 발화행위를 어떻게 수행하는지를 설문지 방식에 근거하여 상호 문화적인 관점에서 탐색하고 있다. 특히 발화행위의 언어적 실현 전략형태들이나 메시지의 표현 전달경로, 그리고 불만표시 빈도수와 관련하여 문화적 상이성과 이에 영향을 미치는 요인들이 무엇인지를 체계적으로 기술하고 있다. 이 연구의 결과를 간단히 요약하면 다음과 같다. 한국인들은 가능하면 화자와 청자의 체면위협을 최소화시키는 "완화어법"이나 "이유"와 같은 간접적인 표현방식의 전략을 선호하며, 특히 비모국어 화자인 한국인은 상세한 이유전략을 사용함으로써 모국어 화자인 독일인보다 발화길이가 더 길게 나타나고 있다. 이와는 달리 독일인 화자들은 불만 표시 빈도수가 한국인들에 비해 높게 나타나며 그들의 불만표시 언어전략 선택은 대부분 객관적인 사실 기준에 따라 직접적인 강화어법이, 즉 비판에서 심지어는 경고나 위협에 이르기까지 다양하게 나타나고 있다. 결국 이런 문화적인 상이성은 상호 문화간의 의사소통 과정에서 화용론적 실패나 소통의 단절을 초래할 수 있다. 따라서 학습자들이 외국어 학습과정에서 목표문화의 구성원들과 효율적으로 의사소통을 하기위해서는 그들의 문법적 체계 외에도 화용론적 규칙에 대한 지식 또한 반드시 습득할 필요가 있다고 본다. In this paper, we investigate the way in which Korean learners of German and native speakers of Korean and German perform the speech act of complaining, specifically with respect to its linguistic realization patterns, frequency and channel of message transmission. It is our objective to describe some of the culturally specific differences and features. The data under study has been collected by using written discourse completion tests. This study shows that social-cultural determination and contextual parameters such as social and situational factors are of crucial importance for the performance of the speech act of complaining, which holds for the Korean and the German cultural alike. Especially when realization patterns of non-native speakers are compared with those of native speakers of the target language strong differences in regard of frequency, strategy selection, use of intensfiers, softners and length of utterance become apparent. Korean learners of German tend to complain less using longer utterances and more softners, which serve to mitigate the face-threatening act of complaint. Cross-cultural comparisons between native speaker of Korean and German also differ in respect of the channel of message transmission. Koreans attempt to select more the indirect strategies (written notes or via caretaker) in order to protect their face wants and social harmony in the interaction. The Germans, on the other hand, in order to achieve the same goals prefer to perform the speech act of complaint directly in face to face interaction. Such cultural differences are able to make more difficult the understanding in the intercultural communication. Therefore a learner needs to know how to communicate effectively as "competent" speakers in the target culture in order to achieve the goal of speech act of complaining successfully.

상표를 통한 후발자 견제전략에 관한 연구

오환종,이상욱 군산대학교 지역개발연구소 1998 地域開發硏究 Vol.10 No.-

The first step into a new market is very attractive to a company although it involves many risk factors. This is due to the fact that there are many pioneer it has been believed, by the business circle and the academic circle, that the company is continuously on top when it comes to competition compared to follower companies. However on the contrary some studies show that market pioneers don't always have more advantage rather than followers. Pioneer is solve the problem. This study shows the brand strategy. Especially, brand extension strategy is very important. A major factor in brand extension is the cost of marketing. Therefore, pioneer must be consider the brand extension strategy to defense that follower's attack. Before setting about any practical extension, there are one preparatory stage.