• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.10 no.4
• /
• pp.318-323
• /
• 2000

The intercalated compounds of alkylsulfonates into hydrated zinc were synthesized. From the high temperature powder X-ray diffraction (HTXRD), FT-IR, and molecular size, the temperature dependence of orientation for the intercalated alkylsulfonates were determined. In the temperatures range 1, alkylsulfonates were intercalated into hexa aqua zinc layer with the bilayer structure of $32.9^{\circ}$angle for ${Zn(H_2O_4]^{2+}[C_nH_{2n+1}SO_3]_2\;^-$. In the temperatures range 2, alkylsulfonates were intercalated into tetra aqua zinc layer with the bilayer structure of $55.2^{\circ}$angle for ${Zn(C_nH_{2n+1}SO_3)_2$. In the temperatures range 3, alkylsulfonates were directly bonded to zinc ion with the bilayer structure of $76.5^{\circ}$angle for ${Zn(C_nH_{2n+1}SO_3)_2$.

• Journal of the Korean Magnetics Society
• /
• v.25 no.5
• /
• pp.139-143
• /
• 2015

The surface magnetism of the CsCl structured Co binary compounds, CoX (X = Ti, V, Nb) (001) surface was studied with the calculated electronic structure data obtained by the full-potential linearized augmented plane-wave (FLAPW) method. The magnetic moment of the surface Co atom of the Co-terminated CoTi(001) system was $1.19{\mu}_B$, which is enhanced compared with that of the Co atom in the center layer. The magnetic moment of the surface V atom in the V terminated the CoV(001) system was $1.64{\mu}_B$, which is more than twice of the center layered V atom. The magnetic moment of surface Co atom in the Co terminated CoV(001) system has the value of $1.34{\mu}_B$, little bit smaller than the bulk value. The magnetism was disappeared in the Co terminated CoNb(001) system, and the magnetic moment of the surface Nb atom in the Nb terminated CoNb(001) system was $0.26{\mu}_B$ which is little bit decreased compared to the center layer value.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2333-2336
• /
• 2010

$TiO_2$ thin films were synthesized on carbon fibers using chemical vapor deposition. We show that these films can exhibit extraordinarily high absorption capacities of toluene vapor. Such an absorption phenomenon of toluene at room temperature was not found for other $TiO_2$ samples. Upon toluene absorption change in the color (darkening) of the film was found, indicating that these films can be used as an indicator of the existence of volatile organic compounds in the indoor environments. By X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM), a high concentration of OH species and a unique layered structure were found for the $TiO_2$ films and these could be related to their high absorption capacity of toluene.

• Carbon letters
• /
• v.25
• /
• pp.43-49
• /
• 2018

This study suggests the novel thermoplastic toughening agent, which can be applied in the monomer forms without increasing the viscosity of the epoxy resin and polymerized during the resin curing. The diazide (p-BAB) and dialkyne (SPB) compounds are synthesized and mixed with the epoxy resin and the carbon fiber reinforced epoxy composites are prepared using vacuum infusion process (VIP). Then, flexural and drop weight tests are performed to evaluate the improvement in the toughness of the prepared composites to investigate the potential of the novel toughening agent. When 10 phr of p-BAB and SPB is added, the flexural properties are improved, maintaining the modulus as well as the toughness is improved. Even with a small amount of polytriazolesulfone polymerized, due to the filtering effect of the solid SPB by the layered carbon fabrics during the VIP, the toughening and strengthening effect were observed from the novel toughening agent, which could be added in monomer forms, p-BAB and SPB. This suggests that the novel toughening agent has a potential to be used for the composites prepared from viscosity sensitive process, such as resin transfer molding and VIP.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.3
• /
• pp.1-4
• /
• 2018

The effect of sulfate substitution on the formation of (Pb,S)-1201 type phase was investigated. Polycrystalline samples with nominal compositions of $(Pb_{0.5}B_{0.5-x}S_x)(Sr_{2-y}La_y)CuO_z$, (x = 0 - 0.5, y = 0.7 - 1.0) and $(Pb_{0.5}S_{0.5})(Sr_{2-y}La_y)CuO_z$ (y = 0.5 - 1.0) were prepared by using a solid-state reaction method. The samples were characterized by powder X-ray diffraction (XRD) and resistivity measurements. XRD data revealed that almost-single (Pb,S)-1201 phase samples could be obtained for x = 0.5 and y = 0.9-1.0, judging from the similar results of the XRD patterns between the (Pb,S)-1201 and (Pb,B)-1201 phases. Each of the samples has a crystal structure with tetragonal symmetry. The sample with x = 0.5 and y = 0.9 is found to show an onset of resistivity dropping at over 23 K and zero resistivity at 12 K.

• Herbal Formula Science
• /
• v.28 no.3
• /
• pp.243-254
• /
• 2020

Objectives : Network pharmacology analysis is commonly used to investigate the synergies and potential mechanisms of multiple compounds by analyzing complex, multi-layered networks. We used TCMSP and BATMAN-TCM databases to compare results of network pharmacological analysis between White Ginseng(WG) and Red Ginseng(RG). Methods : WG and RG were compared with components and their target molecules using TCMSP database, and compound-target-pathway/disease networks were compared using BATMAN-TCM database. Results : Through TCMSP, 104 kinds of target molecules were derived from WG and 38 kinds were derived from RG. Using the BATMAN-TCM database, target pathways and diseases were screened, and more target pathways and diseases were screened compared to RG due to the high composition of WG ingredients. Analysis of component-target-pathway/disease network using network analysis tools provided by BATMAN-TCM showed that WG formed more networks than RG. Conclusions : Network pharmacology analysis can be effectively performed using various databases used in system biology research, and although the materials that have been reported in the past can be used efficiently for research on diseases related to targets, the results are unreliable if prior studies are focused on limited or narrow research areas.

• Journal of Powder Materials
• /
• v.24 no.2
• /
• pp.87-95
• /
• 2017

Lithium silicate, a lithium-ion conducting ceramic, is coated on a layer-structured lithium nickel manganese oxide ($LiNi_{0.7}Mn_{0.3}O_2$). Residual lithium compounds ($Li_2CO_3$ and LiOH) on the surface of the cathode material and $SiO_2$ derived from tetraethylorthosilicate are used as lithium and silicon sources, respectively. Powder X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy analyses show that lithium silicate is coated uniformly on the cathode particles. Charge and discharge tests of the samples show that the coating can enhance the rate capability and cycle life performance. The improvements are attributed to the reduced interfacial resistance originating from suppression of solid-electrolyte interface (SEI) formation and dissolution of Ni and Mn due to the coating. An X-ray photoelectron spectroscopy study of the cycled electrodes shows that nickel oxide and manganese oxide particles are formed on the surface of the electrode and that greater decomposition of the electrolyte occurs for the bare sample, which confirms the assumption that SEI formation and Ni and Mn dissolution can be reduced using the coating process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.2
• /
• pp.126-130
• /
• 2015

In this study, some materials are organized and experimented with variables to obtain the optimum mix proportion for the mechanical property of halogen free flame resistance compound with varying addition of nano clay. Tensile strength, density and stiffness are tested in the room temperature. In this study, unlike existing layered structure, nano clay with tabular structure is used and sufficient stiffness, strength, thermal stability and gas block capability can be achieved with small amount of addition. Tensile strength and elongation test show high rupture strength only in specimens with compatibilizing agents while density test shows average measurement in all the specimens except T-9. It was confirmed that the measurement value according to the additives in compatibilizing agent or in nano clay of hardness test represents similarly.

• Journal of Powder Materials
• /
• v.28 no.2
• /
• pp.150-163
• /
• 2021

Interest in eco-friendly materials with high efficiencies is increasing significantly as science and technology undergo a paradigm shift toward environment-friendly and sustainable development. MXenes, a class of two-dimensional inorganic compounds, are generally defined as transition metal carbides or nitrides composed of few-atoms-thick layers with functional groups. Recently MXenes, because of their desirable electrical, thermal, and mechanical properties that emerge from conductive layered structures with tunable surface terminations, have garnered significant attention as promising candidates for energy storage applications (e.g., supercapacitors and electrode materials for Li-ion batteries), water purification, and gas sensors. In this review, we introduce MXenes and describe their properties and research trends by classifying them into two main categories: transition metal carbides and nitrides, including Ti-based MXenes, Mo-based MXenes, and Nb-based MXenes.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.8
• /
• pp.18-24
• /
• 2021

Polymers, polymer compounds, are very moldable at low temperatures and have good strength against weight, and hence, are often used in the interior and exterior materials of cars. Owing to the increasing environmental problems, emission regulations have become stricter, which has increased the use of lightweight polymers as substitutes for metal materials. Therefore, as the use of polymer increases, extensive research is being conducted on the bonding technology of polymers, such as polyurethane and epoxy. However, the increased cost and environmental pollution by adhesives caused by the polymer manufacturing plant depend on the chemical composition or the manufacturer's mix ratio. To compensate for this issue, a laser beam is irradiated through a highly permeable polymer (PC) placed on top of an absorbent polymer (ABS) to transfer the laser output to the ABS polymer and fuse them at the interface. Moreover, enabling laser penetrating bonding by placing a stainless steel wire mesh between the two polymers can achieve improved bonding strength compared to conventional heterogeneous polymer bonding.