• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.555-555
• /
• 2012

The thermal stability of poly(sodium 4-styrenesulfonate) intercalated graphite oxide has been investigated using a differential scanning calorimeter. The poly(sodium 4-styrenesulfonate) intercalated graphite oxide composite shows a prominent exothermic reaction near $207^{\circ}C$ and an endothermic reaction near $453^{\circ}C$. Graphite oxide is responsible for the exothermic reaction while the endothermic reaction is caused by the poly(sodium 4-styrenesulfonate) used in the synthesis of poly(sodium 4-styrenesulfonate) intercalated graphite oxide. The onset temperature of the exothermic reaction of poly(sodium 4-styrenesulfonate) intercalated graphite oxide decreased by $92^{\circ}C$ in comparison with that of graphite oxide, indicating the addition of poly(sodium 4-styrenesulfonate) in the composite has diminished the thermal stability of graphite oxide.

• Applied Microscopy
• /
• 제50권
• /
• pp.20.1-20.9
• /
• 2020

Arthropods have an open circulatory system with a simple tubular heart, so it has been estimated that the contractile pumping structure of the cardiac muscle will be less efficient than that of vertebrates. Nevertheless, certain arthropods are known to have far superior properties and characteristics than vertebrates, so we investigated the fine structural features of intercalated discs and cardiac junctions of cardiac muscle cells in the black widow spider Latrodectus mactans. Characteristically, the spider cardiac muscle has typical striated features and represents a functional syncytium that supports multiple connections to adjacent cells by intercalated discs. Histologically, the boundary lamina of each sarcolemma connects to the basement membrane to form an elastic sheath, and the extracellular matrix allows the cells to be anchored to other tissues. Since the intercalated disc is also part of sarcolemma, it contains gap junctions for depolarization and desmosomes that keep the fibers together during cardiac muscle contraction. Furthermore, fascia adherens and macula adherens (desmosomes) were also identified as cell junctions in both sarcolemma and intercalated discs. To enable the coordinated heartbeat of the cardiac muscle, the muscle fibers have neuronal innervations by multiple axons from the motor ganglion.

• 한국세라믹학회지
• /
• 제30권10호
• /
• pp.797-802
• /
• 1993

Graphite fiber intercalated compound was deintercalated at $25^{\circ}C$, 65% of humidity and its deintercalated compound was discussed, based on the X-ray diffraction analysis, electrical resistivity measurement, and UV/VIS spectrometer measurements. During deintercalation, the structure was changed in orderlongrightarrowdisorderlongrightarroworder, and resistivity was decreased in the disorder state of the structure, which reflectance minimum of the UV/VIS spectrum ranged from 660 to 750nm (1.88~1.65eV).

• Bulletin of the Korean Chemical Society
• /
• 제27권9호
• /
• pp.1323-1328
• /
• 2006

Mesoporous nickel intercalated aluminosilicate nanohybrid has been synthesized through a recombination reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and aqueous nickel acetate solution. According to powder X-ray diffraction and field emission-scanning electron microscopic analyses, the intercalation of nickel species expands significantly the basal spacing of the host montmorillonite clay and the crystallites of the intercalation compound are assembled to form a house-of-card structure. $N_2$ adsorption-desorption isotherm measurements with BJH pore analyses clearly demonstrated that the porosity of the intercalate originates mainly from mesopores (diameter $\sim50\;\AA$) formed by the house-of-card type stacking of clay crystallites. From FT-IR and X-ray absorption spectroscopic analyses, it becomes certain that intercalated nickel ion is stabilized in an isolated $NiO_6$ octahedral unit. The present mesoporous intercalation compound is expected to be applicable as efficient catalysts or absorbents.

• Bulletin of the Korean Chemical Society
• /
• 제32권4호
• /
• pp.1273-1276
• /
• 2011

Laponite samples intercalated with $Tb^{3+}$ or $Tb^{3+},Ce^{3+}$ ions were prepared by exchange of Na+ ions in interlayers with $Tb^{3+}$ or $Ce^{3+}$ ions. Strong green and weak blue emissions under vacuum ultraviolet (VUV) excitation (${\lambda}$ = 158 nm) were observed due to the $^5D_4{\rightarrow}^7F_J$ and $^5D_3{\rightarrow}^7F_J$ emission lines, respectively. $Tb^{3+}$ ions in an interlayer of laponite mainly existed in ion pairs or clusters, as evidenced by the concentration-dependent luminescence of the $Tb^{3+}$ ions on the relative intensities of the $^5D_3{\rightarrow}^7F_J$ and the $^5D_4{\rightarrow}^7F_J$ emission lines, due to the action of a cross-relaxation process. The addition of $Ce^{3+}$ ions increased the thermal stability of $Tb^{3+}$ intercalated laponite up to $650^{\circ}C$ and quenched the $^5D_3{\rightarrow}^7F_J$ emission lines, probably by promoting the formation of $Tb^{3+}$ ion pairs at relatively low $Tb^{3+}$ concentrations.

• 한국재료학회지
• /
• 제27권3호
• /
• pp.161-165
• /
• 2017

In this paper, synthesis of terephthalate intercalated Zn-Al: Layered double hydroxides (LDHs) was studied. We designed freestanding Zn-Al: carbonate LDH nanosheets for a facile exchange technique. The as-prepared Zn-Al carbonate LDHs were converted to terephthalate intercalated Zn-Al:LDHs by ion exchange method. Initially, Al-doped ZnO (AZO) thin films were deposited on p-Si (001) by facing target sputtering. For synthesis of free standing carbonate Zn-Al:LDH, we dipped the AZO thin film in naturally carbonated water for 3 hours. Further, Zn-Al: carbonate LDH nanosheets were immersed in terepthalic acid (TA) solution. The ion exchange phenomena in the terephthalate assisted Zn-Al:LDH were confirmed using FT-IR analysis. The crystal structure of terephthalate intercalated Zn-Al:LDH was investigated by XRD pattern analysis with different mole concentrations of TA solution and reaction times. The optimal conditions for intercalation of terephthalate from carbonated Zn-Al LDH were established using 0.3 M aqueous solution of TA for 24 hours.

• 치과방사선
• /
• 제18권1호
• /
• pp.177-187
• /
• 1988

This study was designed to investigate the effects of split irradiation on the salivary ductal cells, especially on the intercalated cells of the rat parotid glands. For this study, 24 Sprague-Dawley strain rats were irradiated on the head and neck region with two equal split doses of 9Gy for a 4 hours interval by Co-60 teletherapy unit, Picker's model 4M 60. The conditions of irradiation were that field size, dose rate, SSD and depth were 12×5㎝, 222 cGy/min, 50㎝ and 1㎝, respectively. The experimental animals were sacrificed 1. 2, 3, 6, 12, hours and 1, 3, 7, days after the irradiation and the changes of the irradiated intercalated cells of the parotid glands were examined under light and electron microscope. The results were as follows: 1. By the split irradiation, the degenerative changes of intercalated cells of the parotid glands appeared at 3 hours after irradiation and the most severe cellular degeneration observed at 6 hours after irradiation. The repair processes began from 12 hours after irradiation and have matured progressively. 2. Under electron microscope, loss of nuclear membrane, microvilli and secretory granules, derrangement of chromosomes, degeneration of cytoplasm, atrophy or reduction of intracytoplasmic organelles were observed in the intercalated ductal cells after split irradiation. 3. Under light microscope, derrangement of ductal cells, widening of cytoplasms and nuclei, hyperchromatism and proliferation of ductal cells were observed in intercalated ducts after split irradiation.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.185.2-185.2
• /
• 2014

We have studied the atomic and electronic structure of graphene nanoribbons (GNRs) on a hexagonal boron nitride (h-BN) sheet with intercalated atoms using first-principles calculations. The h-BN sheet is an insulator with the band gap about 6 eV and then it may a good candidate as a supporting dielectric substrate for graphene-based nanodevices. Especially, the h-BN sheet has the similar bond structure as graphene with a slightly longer lattice constant. For the computation, we use the Vienna ab initio simulation package (VASP). The generalized gradient approximation (GGA) in the form of the PBE-type parameterization is employed. The ions are described via the projector augmented wave potentials, and the cutoff energy for the plane-wave basis is set to 400 eV. To include weak van der Waals (vdW) interactions, we adopt the Grimme's DFT-D2 vdW correction based on a semi-empirical GGA-type theory. Our calculations reveal that the localized states appear at the zigzag edge of the GNR on the h-BN sheet due to the flat band of the zigzag edge at the Fermi level and the localized states rapidly decay into the bulk. The open-edged graphene with a large corrugation allows some space between graphene and h-BN sheet. Therefore, atoms or molecules can be intercalated between them. We have considered various types of atoms for intercalation. The atoms are initially placed at the edge of the GNR or inserted in between GNR and h-BN sheet to find the effect of intercalated atoms on the atomic and electronic structure of graphene. We find that the impurity atoms at the edge of GNR are more stable than in between GNR and h-BN sheet for all cases considered. The nickel atom has the lowest energy difference of ~0.2 eV, which means that it is relatively easy to intercalate the Ni atom in this structure. Finally, the magnetic properties of intercalated atoms between GNR and h-BN sheet are investigated.

• 공업화학
• /
• 제18권5호
• /
• pp.449-453
• /
• 2007

리튬이온이차전지에 사용되는 탄소부극의 성능 향상을 위하여 새로운 탄소부극물질로서 Sn-GIC (Graphite intercalated compound)를 합성하고 그 전기화학적 특성을 조사하였다. 합성시 $SnCl_2$ 수용액의 농도가 증가할수록, 그리고 수용액에 함침한 후 건조한 시료의 열처리 온도가 증가할수록 흑연에 삽입되는 Sn의 함량이 증가하였으며, 또한 흑연 내부로 삽입된 Sn의 함량이 증가함에 따라 이를 부극활물질로 사용한 cell의 초기 방전용량은 증가하였다. 가장 우수한 특성을 나타내는 1.0M $SnCl_2$ 수용액에 함침한 후 $900^{\circ}C$에서 열처리하여 제조한 Sn-GIC는 346 mA/g의 초기용량과 10 cycle 후 13%의 용량감소를 나타내었다.

• 한국결정성장학회지
• /
• 제9권6호
• /
• pp.580-584
• /
• 1999

수화된 니켈에 데칸술폰이 층간 삽입된 화합물을 합성한 후 성질을 확인하였다. 화합물의 층상구조는 고온 X-선 회절 데이터로 확인하였다. 온도가 증가하면 층간 삽입된 니켈화합물의 구조가 변하는 것과 동시에 화합물의 층 거리가 24.7 $\AA$에서 30.5 $\AA$가지 증가하였다. X-선 회절 데이터와 데칸술폰의 크기로부터 니켈 층에 결합된 데칸술폰의 공간배열을 결정하였다. 이중 층 구조를 가진 데칸술폰의 분자 축은 니켈 층에 경사진 각도로 수직하게 배열되어있다.