• Title/Summary/Keyword: Chair structure

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The Solvent-Independent Structure of Piroxicam (피록시캄의 용매 비의존 결정구조)

  • Kim, Bong-Hee;Suh, Il-Hwan;Jhee, Ok-In;Suh, Jong-Myung;Suh, Jung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.18 no.4
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    • pp.209-215
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    • 1988
  • The three-dimensional structures of piroxicam crystallized from two different solvents, toluene and toluene/hexane mixture respectively, are proved identical: $C_{15}H_{13}N_3O_4S,\;M\;=\;331.35$, monoclinic, a = 7.128(1), b = 15.146(2), c = 13.956(2) ${\AA},\;{\beta}=\;97.33(1)^{\circ},\;V\;=\;1494.37{\AA}^{3},\;Dx\;=\;1.472\;g/cm^{3},\;Z\;=\;4,\;space\;group\;P2_{1}/c,\;Mo\;K{\alpha}(\lambda=\;0.71073\;{\AA})$, F(000) = 688, T = 295 K, R = 0.0611 for 1993 unique observed reflections. The thiazine ring exhibits a half chair conformation. An amide group is involved in an intramolecular hydrogen bond to the hydroxy group, O(17)-H(17)${\cdots}O(15){\AA}$. The molecule is planar within 2 ${\AA}$ with the interplanar angle $127.9(4)^{\circ}$ between pyridine and benzene rings. A molecular chain parallel to [011] is formed by two intermolecular hydrogen bonds N(16)-H(6)${\cdots}O(11)$ and C(6)-H(6)${\cdots}O(11)$, and the molecular chains are held together by van der Waals forces.

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Crystal Structure of 3-[4-(2-Ethoxy-2-phenylethyl)-1-piperazinyl]-2-methyl-1-phenyl-1-propanone (Eprazinone) dihydrochloride, $C_{24}H_{32}N_2O_2$·2HCl

  • Euisung Kim;Hyun Song;Choong-Souh Yun;Hyun-So Shin
    • Bulletin of the Korean Chemical Society
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    • v.12 no.4
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    • pp.371-373
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    • 1991
  • The crystal structure of eprazinone dihydrochloride, $C_{24}H_{32}N_2O_2$${\cdot}$2HCl, has been determined from 2102 independent reflections collected on an automated Nonious CAD-4 diffractometer using graphite-monochromated $Mo-K\alpha$ radiation. The crystals are monoclinic, space group P$2_1$/n, with unit cell dimensions a=11.381(2), b=28.318(2), c=7.840(1) $\AA$, $\beta=92.45(2)^{\circ}$, ${\mu}=2.37$ c$m^{-1}$, F(000)=968, and Z=4. Final R value is 0.071 for independent 2102 observed reflections. The molecule assumes an extended conformation. The piperazine ring has a normal chair conformation and the four carbon atom are planar with a maximum displacement of 0.004 $\AA$ for C(18) atom. The two chloride ions are hydrogen bonded to the two piperazine nitrogen atoms [N(14)${\cdot}{\cdot}{\cdot}$Cl(1); 2.986(6) $\AA$ N(17)…Cl(2); 3.084(8) $\AA$].

Theoretical Investigation on the Structure, Detonation Performance and Pyrolysis Mechanism of 4,6,8-Trinitro-4,5,7,8-tetrahydro -6H-furazano[3,4-f]-1,3,5-triazepine

  • Li, Xiao-Hong;Zhang, Rui-Zhou;Zhang, Xian-Zhou
    • Bulletin of the Korean Chemical Society
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    • v.35 no.5
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    • pp.1479-1484
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    • 2014
  • Based on the full optimized molecular geometric structures at B3LYP/cc-pvtz method, a new designed compound, 4,6,8-trinitro-4,5,7,8-tetrahydro-6H-furazano[3,4-f ]-1,3,5-triazepine was investigated in order to look for high energy density compounds (HEDCs). The analysis of the molecular structure indicates that the seven-membered ring adopts chair conformation and there exist intramolecular hydrogen bond interactions. IR spectrum and heat of formation (HOF) were predicted. The detonation velocity and pressure were evaluated by using Kamlet-Jacobs equations based on the theoretical density and condensed HOF. The bond dissociation energies and bond orders for the weakest bonds were analyzed to investigate the thermal stability of the title compound. The results show that $N_1-N_6$ bond is the trigger bond. The crystal structure obtained by molecular mechanics belongs to $Pna2_1$ space group, with lattice parameters Z = 4, a = 15.3023 ${\AA}$, b = 5.7882 ${\AA}$, c = 11.0471 ${\AA}$, ${\rho}=2.06gcm^{-3}$. In addition, the analysis of frontier molecular orbital shows the title compound has good stability and high chemical hardness.

A Study on Comparing Characteristics of Le Corbusier′s Furniture Design with Alvar Aalto′s (르 꼬르뷔지에와 알바 알토의 가구디자인 특성 비교 연구)

  • 이진영
    • Korean Institute of Interior Design Journal
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    • v.13 no.5
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    • pp.162-172
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    • 2004
  • Architects and designers of the 20th Century made various efforts to establish new design languages reflecting the changes of society, the times, and environment. They used furniture, especially chairs, as controversial items of aesthetic value, society and ideology. Le Corbusier and Alvar Aalto are furniture designers as well as architects, who adopted this ‘spirit of the times’ actively and have greatly contributed to modernism. This study will help us to understand the diversity of design since modernism, by comparing these two designers' furniture design. It also covers the common factors In modern furniture design, and analyses their individuality and likeness In design. The following is a comparison of furniture design by Le Corbusier and Alvar Aalto. Le Courbusier linked International design and Aalto linked Rational design and Organic concept design to their furniture, just as they did in their architecture. They were able to establish the base of modern furniture design by adapting new concepts and pursuing humanism. In structure, Le Corbusier's furniture Is simple and proportional. It demonstrates a sophisticated geometric composition, mechanical beauty. On the other hand, Aalto rationally linked nature with human requirements and his furniture is organic and in harmony with geometric structure. In function, Le Corbusier's furniture is standardized and prefabricated. He designed for the user so they could choose to use the furniture efficiently to suit their needs. In comparison with Le Corbusier, Aalto Invented the ‘Stacking Chair’ which allows a more effective use of space and reflected the structure of the human body to improve the user's comfort. In materials and techniques, Le Corbusier used new materials like metal or leather, and attempted new ways such as welding, prefabrication, and standardization for production. On the contrary, Alto mainly used birch, which is the traditional material in Finland, and tried new bent wood techniques and joining methods.

On a "duality" of the Corps-actant structure in Misaeng: with Jang Geurae as the central figure (『미생』에 나타난 신체 행위소 구조의 이중성에 관한 고찰 - 장그래를 중심으로)

  • Song, Taemi
    • 기호학연구
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    • no.57
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    • pp.211-255
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    • 2018
  • This paper attempts to "re-read" the webtoon Misaeng, which was once an important issue in the field of public discourse on "labor". Our hypothesis was that the dual actactial structure of Misaeng's hero Jang Geurae gave a dual structure to the entire text, which leads to the discovery of text meaning that was not mentioned in the existing discourse. This is based on the concept of 'meta-story character', which Hiroki Azuma talked in his postmodern literary theory. To verify this hypothesis we analyzed the text by applying the Parisian semiotics, more specifically J. Fontanille's theory. Jang Geurae is observed to be a actant of dual structure divided into 'character' of the enunciated level and 'player' of the enunciation level. Considering this characteristic of the hero, Misaeng can be interpreted as a metafiction that shows the 'shifting' between the subject of the enunciated level and the subject of the enunciation level. On the level of 'character' Jang's existence mode turns out to be "Deficiency (actualized)", but on the level of 'player' Jang 's existence mode turns out to be "Inanity(potentiallized)." His somatic responses also show a duality, which is represented by Fontanille's corps-actant model, where on the level of 'character' the somatic actant of Jang consists of 'Moi-chair(ego-flesh)' and 'Soi-idem(self-idem)', and on the level of 'player' it consists of 'Moi-chair(ego-flesh)' and 'Soi-ipse(self-ipse)'. The former mainly acts as a 'role' and takes charge of exteroceptive perception, while the latter mainly acts as 'attitude' and takes charge of interoceptive perception. Because of this dissociative nature of actant, Jang's two 'self' draw the re-adjustment of values without serious conflict between the collective norms and the individual identity. This is in sharp contrast with other characters who struggle with the conflict between the environment and "self". It becomes customary to adopt norms that are suspected to ineffective, but if you raise questions, the normative system can be updated. On one axis of Misaeng there are characters who have lost themselves in customs. On the other axis, there is Jang who can not help dismantling the existing ineffective norms and updating the normative system. Jang's existence mode seems to be one of many possible modes generated by this era where people share no longer solid community values, His actantial structure also communicates with readers of these days who put themselves more in subject of enunciation level than of enunciated level.

Guided endodontics: a case report of maxillary lateral incisors with multiple dens invaginatus

  • Ali, Afzal;Arslan, Hakan
    • Restorative Dentistry and Endodontics
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    • v.44 no.4
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    • pp.38.1-38.8
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    • 2019
  • Navigation of the main root canal and dealing with a dens invaginatus (DI) is a challenging task in clinical practice. Recently, the guided endodontics technique has become an alternative method for accessing root canals, surgical cavities, and calcified root canals without causing iatrogenic damage to tissue. In this case report, the use of the guided endodontics technique for two maxillary lateral incisors with multiple DIs is described. A 16-year-old female patient was referred with the chief complaint of pain and discoloured upper front teeth. Based on clinical and radiographic findings, a diagnosis of pulp necrosis and chronic periapical abscess associated with double DI (Oehler's type II) was established for the upper left lateral maxillary incisor (tooth #22). Root canal treatment and the sealing of double DI with mineral trioxide aggregate was planned for tooth #22. For tooth #12 (Oehler's type II), preventive sealing of the DI was planned. Minimally invasive access to the double DI and the main root canal of tooth #22, and to the DI of tooth #12, was achieved using the guided endodontics technique. This technique can be a valuable tool because it reduces chair-time and, more importantly, the risk of iatrogenic damage to the tooth structure.

The Crystal and Molecular Structures of Neo-inositol and Two Forms of Scyllo-inositol (Neo-inositol 및 Scyllo-inositol의 結晶 및 分子 構造)

  • Yeon, Younghee
    • Korean Journal of Crystallography
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    • v.12 no.3
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    • pp.150-156
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    • 2001
  • Nea-inositol is triclinic P???, with a =4.799(1), b=6.520(1), c=6.505(1) Å, α=70.61(1), β=69.41(1), γ=73.66(1)°, Z=1, molecular symmetry ???. Scyllo-inositol, from A, is monoclinic, P2₂/c, with a=5.089(1), c=11.948(2)Å, β=116.98(2)°, Z=2, molecular symmetry ???. Form B is triclinic, P???, with a=6.725(1), b=6.797(1), c=8.635(2)° Å, α=95.45(2), β=99.49(2), γ=99.19(2)°, Z=2, molecular symmetry ???. This crystal structure is pseudo-monoclinic, having two centrosymmetrical molecules with the almost identical conformation and orientation in the crystal lattice. The molecules have the expected chair conformations with puckering parameters of Q=0.609(2)Å for n대, 0.581(2)Å for Scyllo-A, and 0.566(2) Å for Scyllo-B. The bond lengths and angles are normal, C-C, 1.505 to 1.531 8A, C-O, 1.415 to 1.440 Å, C-C-C, 108.2 to 112.9°. The molecules are linked by systems of finite and infinite chains of hydrogen bonds.

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A Study on the Structure Design for the Desk Chair of the Folding Desk type in the Lecture (강의실용 의자 일체형 책상 접이구조 설계방안에 관한 연구)

  • Kim, Duck-You;Kim, Pyeong-Gyeong;Jeon, Euy-Sik
    • Proceedings of the KAIS Fall Conference
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    • 2008.11a
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    • pp.430-432
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    • 2008
  • 학교와 같이 대단위 교육을 수행하는 곳에서 필수적으로 사용되는 것은 강의실 의자이다. 소비자 중심적인 시대적 변화에 따라 많은 제품들이 다양한 소비자의 요구가 반영되어 출시되고 있으나, 강의실 의자는 아직 이러한 요구가 받아들여지지 않거나 무시되고 있다. 강의실에서 학생들이 가장 불편해 하는것은 자신의 신체치수에 적합하지 않는 강의실 의자이다. 따라서 본 연구에서는 다양한 신체치수를 반영할 수 있는 가변형 강의실용 의자를 개발하고자 한다. 신체치수는 앉은키와 체형을 고려하여 앉고 일어서는데 불편함이 없도록 책상 접힘과 의자와의 거리조절이 가능하고, 사람의 신장에 따라 높낮이 조절이 가능한 구조로 설계하여 기존의 평균책상 사이즈에 구애받지 않고 사용자의 신체구조에 따라 자유롭게 조절시켜 장시간 의자에 앉아 있을 때 불편함을 개선하고 불균형한 자세 등을 교정시켜 줌으로써, 학업 시 바른 자세를 유도하며 학업능률을 향상시킬 것으로 기대한다.

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The Crystal and Molecular Structure of Salicylaldehyde-4-morpholinothiosemicarbazone (Salicylaldehyde-4-morpholinothiosemicarbazone의 결정 및 분자구조)

  • C. H. Koo;H. S. Kim;C. T. Ahn
    • Journal of the Korean Chemical Society
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    • v.21 no.1
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    • pp.3-15
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    • 1977
  • Crystals of salicylaldehyde-4-morpholinothiosemicarbazone, $C_{12}H_{15}O_2N_3S$, are orthorhombic with space group Pna21. Unit-cell dimensions are a = 11.85(5), b = 15.45(5) c = 7.18(3)${\AA}$ with z = 4. Three-dimensional intensity data were collected from the multiple-film equi-inclination Weissenberg photographs taken with $CuK{\alpha}$ radiation. The intensities were estimated visually. The structure was solved by Patterson and Fourier methods and refined by the block-diagonal least-squares methods until the final R value becomes 0.11 for the 1064 observed independent reflections. The morpholine ring has a chair form. The rest atoms of salicylaldehyde-4-morpholinothiosemicarbazone molecule excluding morpholine ring and sulfur atom approximately lie on a plane. The hydroxyl group of the salicylaldehyde and the nitrogen atom of the thiosemicarbazone form an intramolecular hydrogen bond, $O-H{\cdot}{\cdot}{\cdot}N$, of 2.67${\AA}$. The short intermolecular distances all appear to be normal van der Waals contacts.

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The Crystal and Molecular Structure of P-Aminobenzaldehyde Cyclohexylthiosemicarbazone (P-Aminobenzaldehyde Cyclohexylthiosemicarbazone의 결정 및 분자구조)

  • Chung Hoe Koo;Chong Hee Kim;Young Ja Park
    • Journal of the Korean Chemical Society
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    • v.25 no.6
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    • pp.343-350
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    • 1981
  • The crystal and molecular structure of P-aminobenzaldehyde cyclohexylthiosemicarbazone, C14H20N4S, has been determined from 2712 integrated intensities measured on a computer controlled four circle diffractometer with monochromated $CuK_{\alpha}$, X-ray radiation. The crystals are monoclinic, space group C2/c with eight molecules in a unit cell of dimensions, a = 12.488(2), b = 12.276(4), c = 19.997(6)${\AA}$ and ${\beta}=103.55(3)^{\circ}$. The structure was solved by Patterson and Fourier method and refined by a full-matrix least squares method to a final R value of 0.058 for all reflections. The C(8)-S bond is trans to N(2)-N(3) and C(8)-N(1) is cis to N(2)-N(3) bond. The cyclohexane ring has chair conformation and makes an angle of $40.7^{\circ}$ with the benzene ring. The molecules are linked by N(2)H…S hydrogen bonds into dimer-like units which are held together by $N-H{\ldots}N$ hydrogen bonds. Sulfur accepts second rather weak hydrogen bond from N(4). An intramolecular hydrogen bond exists between N(1) and N(3) atoms.

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