• Macromolecular Research
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• 제11권3호
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• pp.152-156
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• 2003

We investigated epitaxial relations of phase transitions between the lamellar (L), hexagonally perforated layers (HPL), and gyroid (G) morphologies in styrene-isoprene diblock copolymer (PSI) and polyisoprene (PI)/PSI blend using rheology and small angle X-ray scattering (SAXS) techniques. In HPLlongrightarrowG transitions, six spot patterns of G phase were observed in two-dimensitional SAXS pattern. On the other hand, in direct L-longrightarrowG transition without appearance of HPL phase, the polydomain patterns of G phase were observed. From present study, it was understood that direct LlongrightarrowG transition of blend may be suppressed by high-energy barrier of transition and mismatches in domain orientation between epitaxially related lattice planes.

• 한국전기전자재료학회논문지
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• 제14권8호
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• pp.629-633
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• 2001

Electrical properties of the $\alpha$-In$_2$Se$_3$ single crystals grown by use of the Bridgman technique were examined in the transition temperature range between $\alpha$-phase and $\beta$-phase. $\alpha$-In$_2$Se$_3$ single crystal has ' the rhombohedral structure and lattice constants are a=4.025 $\AA$, c=28.771 $\AA$ in c-axis. The transition temperatures of the stoichiometric $\alpha$-In$_2$Se$_3$ single crystal is 198.8$^{\circ}C$ according to the specimens. The temperature of $\alpha$longrightarrow$\beta$ phase transition decreased but the temperature of $\beta$longrightarrow$\alpha$ phase transition increased as the number of heating-cooling cycle increased.

• 한국세라믹학회지
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• 제34권7호
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• pp.713-721
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• 1997

Molecular dynamic (MD) simulations with new interatomic potential function including the covalent bond were performed on the phase transition of $\alpha$-quartz-type GeO2 under high pressure. The optimized crystal structure and the pressure dependence of the lattice constant showed higher reproducibility than the previous models and were in very good agreement with the experimental data. A phase transition of $\alpha$-quartz and $\alpha$-quartz-type GeO2 by simulation was found approximately 24 GPa and 6-7 GPa, respectively. This phase transition involved an abrupt volume shrinkage and showed 4-6 coordination mixed structure with the increasing in the coordination number of cation.

• 한국자기공명학회논문지
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• 제21권2호
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• pp.63-66
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• 2017

The $^{14}N$ NMR spectra for $(NH_4)_2SO_4$ crystals were obtained near the phase transition temperature $T_C=223K$, and were found to precisely reflect the symmetry change in the crystal at this first-order phase transition. Changes in the resonance frequencies near $T_C$ were attributed to the structural phase transition. In the ferroelectric and paraelectric phases, two inequivalent NH4 groups were distinguished in the $^{14}N$ NMR spectra. The two types, $NH_4$(1) and $NH_4$(2), have slightly different local environments. Consequently, we conclude that the phase transition is caused by the change in the environment of the $^{14}N$ nuclei in the $NH_4$ groups, rather than by the $SO_4$ groups.

• BMB Reports
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• 제44권1호
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• pp.22-27
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• 2011

A series of elastin-like proteins, $SKGPG[V(VKG)_3VKVPG]_n$-(ELP1-90)WP (n = 1, 2, 3, and 4), were biosynthesized based on the hydrophobic and lysine linkage domains of tropoelastin. The formation of self-assembled hydrophobic aggregates was monitored in order to determine the influence of cationic segments on phase transition properties as well as the sensitivity to changes in salt and pH. The thermal transition profiles of the proteins fused with only one or two cationic blocks (n = 1 or 2) were similar to that of the counterpart ELP1-90. In contrast, diblock proteins that contain 3 and 4 cationic blocks displayed a triphasic profile and no transition, respectively. Upon increasing the salt concentration and pH, a stimulus-induced phase transition from a soluble conformation to an insoluble aggregate was observed. The effects of cationic segments on the stimuli sensitivity of cationic bimodal ELPs were interpreted in terms of their structural and molecular characteristics.

• 한국경영과학회지
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• 제41권1호
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• pp.21-39
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• 2016

Although the demand for IT outsourcing (ITO) has increased recently because of the recent recession, concerns about business discontinuity in the transition phase cause companies to hesitate to adopt ITO. Therefore, a guideline to improve the prospects is needed. However, studies on the success factors of the transition phase in ITO are lacking. In this study, we develop an expert hierarchical value map (HVM) of the success of the transition phase in ITO by using cognition scientific methodologies. We empirically verify how success factors affect the success of the transition phase. Specifically, we derive an HVM of main stakeholders by using in-depth interviews and approaches, such as repertory grid technique (RGT) and laddering, based on means-end chain theory. We validate the success factors empirically through a bipolar analysis of RGT. Finally, we determine the most important cluster of success factors through cluster analysis.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.441-445
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• 2000

A new series of three ring type liquid crystalline compounds containing partially fluorinated alkenyl or alkyl side chains together with fluorine substituted cyclohexylbiphenyls were designed and synthesized in this study. The structures of synthe sized compounds were established by 1 H, 13 C and 19 F NMR spectroscopy. The phase transition temperatures of fluorinated liquid crystalline compounds were determined by cross-polarizing mi-croscopy equipped withhot stage. All compounds were found to have nematic liquid crystalline phase with rel-atively low phase transition temperature and wide liquid crystalline temperature range. The dependence of phase transition temperatures on the chainlength falls into three categories; (a) decreasing transition tempera-tures for 4-fluoro-4'-[4-fluoro-4-(1-fluoroalkyl)cyclohexyl]biphenyl (15) series, (b) higher transition tempera-tures for odd numbered chains for 4-fluoro-4'-[4-fluoro-4-(1-fluoroalk-1-enyl)cyclohexyl]biphenyl (14) series, (c) higher transition temperatures for even numbered chains for 4-[4-(1,2-difluoroalk-1-enyl)-4-fluorocyclo-hexyl]-4'-fluorobiphenyl (16) series.

• 한국해양공학회지
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• 제37권3호
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.99-100
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• 2023

In this study, an approach has been made to understand the effect of encapsulation thickness of the nanoencapsulated PCMs on the phase transition kinetics. Paraffin is encapsulated by silica via single pot polycondensation reaction. Different ratios of silica precursor are chosen to encapsulate paraffin. The obtained encapsulated PCMs are identified as nano sized, as well as with increasing silica precursor, thicker silica encapsulations have been manifested with shrinking core diameter. The synthesized PCMs are characterized using various characterization techniques. Isochronal kinetic studies are done in differential scanning calorimeter (DSC) to understand about their phase transformation behaviors. This study can appreciate the cognition of the large-scale applications of PCMs into the building constructions as well as the fundamental conception on the phase transition kinetics of PCMs can also be amended.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.119-121
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• 1993

Two dimensional phase transition and three dimensional propagation of layer structures of liquid crystal film are investigated by using surface second harmonic generation method. We have found a distinctive first order phase transition between a monolayer phase and a stable 3-layer phase of 8CB liquid crystal film.