• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.330.2-330.2
• /
• 2002

The conformational study on cyclic Ac-Cys-Pro-Xaa-Cys-NHMe (Ac-CPXC-NHMe: X = Ala, Val. Leu. Aib. Gly. His. Phe, Tyr. Asn. and Ser) peptides has been carried out using the ECEPP/3 force field and the hydration shell model in the unhydrated and hydrated states. This work has been undertaken to investigate structural implications of the CPXC sequence as the chain reversal for the initiation of protein folding and as the motif for active site of disulfide oxidoreductases. The backbone conformation DAAA is in common the most feasible for cyclic CPXC peptides in the hydrated state. which has a type 1${\beta}$-turn at the Pro-Xaa sequence. The proline residue and the hydrogen bond between backbones of two cystines appear to play a role in stabilizing this preferred conformation of cycilc CPXC peptides. However. the distributions of backbone conformations and ${\beta}$-turns may indicate that the cyclic CPXC peptide seems to exist as an ensemble of ${\beta}$-turns and coiled conformations. The intirnsic stability of the cyclic CPXC motif itself the active conformation appears to play a role in determining electrochemical properties of disulfide oxidoreductases.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.06a
• /
• pp.90-91
• /
• 2020

As the construction site has become narrower recently, the importance of mass concrete is naturally being highlighted as skyscrapers become popular. However, it is not possible to install the entire volume per day if the mass concrete is installed due to the Remicon 8⦁5 system and the 52-hour workweek system. When the mass concrete base is divided into several days, cold joints occur because the consolidation of joints is not integrated due to different degree of hardening in the case of the previous layer and the next day. As a result, existing research has shown that if super retarding agent are mixed into Ready Mixed Concrete (hereinafter referred to as Remicon) using sugar as a raw material to delay the curing time of concrete, cold joints are inhibited and cracks are inhibited by reducing the initial hydration heat.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.169-170
• /
• 2023

In this study, light-heat generating materials were produced in two ways, and the performance of two light-generating insulation sheets was reviewed. As a result of the experiment, it was possible to confirm the improved heating performance of the light heating insulation sheet compared to the existing bubble sheet. The light heat insulation sheet (b) showed improved thermal properties compared to the existing bubble sheet, and it is believed that the temperature has increased due to the combined effect of initial hydration heat and heat generation after installation. In future studies additional experiments are needed to compensate for the insufficient insulation performance due to the single bubble sheet through the double bubble sheet and to adjust the amount of light-generating materials added as a consideration of the optimal heat-generating effect of the light-generating insulation sheet (b).

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.11a
• /
• pp.69-70
• /
• 2023

The development of advanced 3D printing technologies has opened up new opportunities for customized digital designs in the construction industry. Using nano- and micro-scale additives is expected to improve the performance of cement-based materials in 3D printing. TiO₂ particles have been widely used as reinforcing additives in cement-based materials. Therefore, this study aims to investigate the application of cement-based materials containing multi-size TiO₂ particles in binder jet 3D printing and the effect of different-size TiO₂ particles on the performance of printed samples. TiO₂ particles exhibit an excellent filling effect, which increases the density of the printed samples and promotes hydration, thereby improving the compressive strength of the samples. In addition, larger TiO₂ particles exert more pronounced filling and photocatalytic effects on the resulting samples.

• Applied Chemistry for Engineering
• /
• v.17 no.2
• /
• pp.138-143
• /
• 2006

Ethosome is a liquid crystalline vesicle prepared by hydration of ethanol-dissolved lecithin with a solution containing hydrophilic components. Investigation of factors affecting the entrapment efficiency and particle size of ethosomes was carried out, because the high entrapment efficiency and small particle size are prerequisite in developing ethosomes as a drug delivery system. The variations of properties of ethosomes with constituent composition and preparation method were examined using a calcein as a hydrophilic marker. It was observed that the amount of ethanol and calcein solution, phosphatidyl choline content in lecithin, preparation temperature, stirring rate, and PBS addition method had a considerable effect on the properties of ethosome. Sonication treatment resulted in the reduction of entrapment efficiency of ethosome, which was due to the release of entrapped components in the vesicles by strong sonication vibration.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.6 no.2
• /
• pp.67-73
• /
• 2011

In this study, it was investigated compressive strength generation of concrete using high volume mineral admixture obtaining fundamental data for the application of concrete structure in construction field. For this, it was evaluated compressive strength with unit binder contents($310{\sim}410kg/m^3$), replacement ratio of mineral admixture(70~90%), unit water contents($140{\sim}150kg/m^3$) and curing temperature in the normal strength range. Also, after producing mock-up structure, hydration heat and compressive strength generation was evaluated to examine properties in the concrete member. In case of concrete using a large amount of industrial byproducts which was reviewed in this study, it is possible to secure compressive strength more than 24MPa at age 28days with about $13^{\circ}C$ ambient temperature of curing condition and that is considered to be applied to structure at construction site.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.4
• /
• pp.285-291
• /
• 2014

Partial replacement of cement with blast furnace slag has many advantages such as the reduction of construction fee, the decrease of hydration heat and the increase of long-term strength. Hence, slag is widely used in practice. This study investigates the effect of slag on the rheological properties of cement paste and mortar. Three different types of slag (BS1, BS2 and BS3) with five different contents (0, 20, 40, 60 and 80 wt.%) were used to replace the cement. Each type of slag has different fineness. Water to binder ratio was 0.5. Test results showed that the partial replacement of BS1 and BS2 decreased flow and increased O-lot flow time, whereas that of BS3 caused an opposite effect, i.e., increased flow and decreased O-lot flow time. It was found that there was a good corelation between the values of yield stress and flow.

• Journal of the Korea Concrete Institute
• /
• v.16 no.5 s.83
• /
• pp.591-596
• /
• 2004

In order to evaluate the applicability of steel slag aggregates for tetrapod concrete, the properties of concrete as structural material were investigated. The biochemical research of marine concrete using steel slag aggregates was also carried out. The tested concrete properties are slump, ai content, compressive strength, splitting tensile strength, elastic modulus, carbonation, hydration heat, freezing and thawing, sulfate attack, drying shrinkage, etc. The biochemical experiments are carried to research the propagation and reproduction of seaweeds and survival of bottom dwelling species. According to this experiment results, the steel slag aggregate content did not have a significant effect on compressive strength, splitting tensile strength and elastic modulus. The durability of concrete was not influenced by the steel slag aggregate content. From the biochemical research, steel slag aggregate can be evaluated as the material that is ideally suited for promoting propagation and reproduction of seaweeds and sessile benthos.

• Journal of the Korean Ceramic Society
• /
• v.41 no.6
• /
• pp.430-434
• /
• 2004

The values of fracture energy and mechanical flexural strength of Fiber Reinforced Cement (FRC) with polypropylene (PP) fiber modified by Ion Assisted Reaction (JAR), by which functional groups were grafted on the surface of PP fiber, was improved about 2 times as those of fracture energy and flexural strength of cement reinforced by untreated PP fiber. PP fiber was irradiated in O$_2$ environment by Ar$\^$+/ ion. The contact angle of PP treated by IAR decreased largely when compared with untreated PP. From this result, we expected that surface energy and interfacial adhesion force of treated PP fiber increased. The strain hardening occurred in the strain-stress curve of FRC including PP treated by IAR when compared with that of FRC with untreated PP. These enhanced mechanical properties might be due to strong interaction between hydrophilic group on modified PP fiber and hydroxyl group in cement matrix. This hydrophilic group on surface modified PP fiber was confirmed by XPS analysis. We clearly observed hydration products that were fixed at modified PP fiber due to the strong adhesion force of interface in cement reinforced modified PP by SEM (Scanning Electron Microscopy) study.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.4
• /
• pp.122-128
• /
• 2010

On the international provision on prohibition of ocean dumping of waste, tap water sludge has been buried or recycled on th low value added product as landfill. Due to the tap water sludge having high inorganic content, differing from the sewage sludge, it is possible to use as a usable resource by suitable process. We have studied on hydro thermal processing of tap water sludge with phosphoric acid and finally synthesize a artificial zeolite having a deodorization property. To use it as a building material, it has to be solidification. This study is on the properties of artificial zeolite synthsized and solidification properties by various types of solidifier. It is showed that the slaked lime is the best on setting property and its optimum content is 30-60 weight proportion. Solid by solidified by slaked lime has low strength and excellent deodorization performance, so it is possible to use as a functional pannel as gypsum board.