• Journal of the Korean Electrochemical Society
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• v.5 no.1
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• pp.30-38
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• 2002

Disordered carbon and boron-substituted disordered carbons $C_{l-x}B_x(x=0.05,\;0.10,\;0.20)$ were synthesized by Pyrolysis of LPG(liquid Propane gas)and $BCl_3$. Their electrochemical properties as anode materials for Li-ion secondary batteries were then investigated. When PVDF is added to the sample in a weight ratio 5 : 95, the disordered carbon with x=0.00 had the first discharge capacity 374 mAh/g. Its cycling performance was relatively good from the second cycle and it had the discharge capacity 258 mAh/g at the 10th cycle. When PVDF is added to the sample in a weight ratio 5 : 95, the sample with x=0.05 among the samples $C_{l-x}B_x(x=0.05,\;0.10,\;0.20)$ exhibited the largest first discharge capacity 860 mAh/g and discharge capacity 181 mAh/g at the 10th cycle. All the samples had similar cycling performances from the second cycle. The sample $C_{0.90}B_{0.10}$ showed the best electrochemical properties as a anode materials fur Li-ion secondary battery from the view points of the first discharge capacity(853 mAh/g when $10w1.\%$ PVDF is used), cycling performance, discharge capacity(400mAh/g at the 10th cycle when $10wt.\%$ PVDF is used). All the samples showed generally larger charge and discharge capacities when $10wt.\%$ PVDF ratter than $5wt.\%$ PVDF is used. The plateau region in the range of voltage lower than 1.25V becomes larger probably since the structure becomes less disordered by the addition of boron. When boron is added, the charge and discharge capacities decreased suddenly at the second cycle. This may be become only a part of Li are reversibly deintercalated and intercalated and a part of Li which are strongly combined with B are not deintercalated. The increases in charge and discharge capacities are considered to be resulted from the increase in the potential of Li in the boron-added carbons, caused by the strengthening of the chemical bond between the intercalated Li and the boron-carbon host since the boron acts as electron acceptor.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.36-43
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• 1996

The crystal structure Tris(ethylenediamine)nickel(II)Dichromate has been determined by X-ray crystallography. Crystal data: a=8.268(2), b=13.865(2), c=14.921(2)Å, γ=102.04(2)°, V=1672.9(5)Å3, Z=4, Monocline, P21/b (space group No.=14), Dcalc=1.806 gcm-3, μ=24.05 cm-0.1. The intensity data were collected with Mo-Kα radiation(λ=0.7107Å) on an automatic four-circle diffractometer with a graphite monochromator. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were R=0.045, Rw=0.051, Rall=0.059 and S=2.171for 2248 observed reflections. The two carbon atoms of a ring of Ni(en)-ion were split into crossed four atoms. In consideration of α- and β-angles of two rings of a disordered ethylenediamine of Nien3-ion and the hydrogen bonds between Ni(en)3-cation and Cr2O7-anion, the configuration of Ni(en)3-ion is assumed to be disordered with Λδδδ and Λδδλ.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.437-442
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• 1991

Temperature and atmosphere dependence of electrical conduction of the metal Cu, Ag, Au films, vaccum evaporated on glass, was investigated. The structural changes of the metal films were examined by SEM and high temperature XRD. The electrical resistance slightly increased with initial temperature increase up to the inflection point and decreased to minimum value, after this rapidly increased with further temperature increased below minimum. These phenomena were caused by the thermally induced film failure as a result of the mass transport. The temperature for the film failure increased in the order of O2, Air, Vacuum, N2, Ar in Cu, Ag films and Air, Vacuum, N2, Ar in Au film. The increase of resistance at the lower temperature range was attributed to the lattice distortion by disordered crystal structure, while the decreasing resistance was attributed to the removal of structural defects and film densification.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.106-110
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• 1995

A structural analysis of dickite prepared by dry grinding with different grinding time has been made by X-ray diffraction. The $SiO_4$ tetrahedra are found to remain unchanged in the ground dickite samples by analysing the radial distribution function(RDF). On the other hand, with an increase of the grinding time a change in oxygen coordination number around aluminum has been quantitatively confirmed. This variation may be attributed to the change of hydroxyl induced by the prolonged grinding.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.177-179
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• 2011

The difference the guide specifications of between housing and land development has been caused many problems, since Korea Land Corporation and Korea Housing Corporation were merged into LH (Land and Housing Corporation) in 2009. Those are that specification criteria to establishing lower level specifications are disordered; duplicated investment on sites; management systems are conflicted site to site, which are based on different operation system from old land and housing corporations, etc. Thus, this paper aims to suggest a direction of integrated guide specification system of LH including improved and advanced classification hierarchy and specification.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.131-135
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• 2006

High electron mobility transistors with InAs channels and antimonide barriers were grown on Si and GaAs substrates by means of molecular beam epitaxy. While direct growth of Sb materials on Si substrate generates disordered and coalescences 3-D growth, smooth and mirror-like 2D growth can be repeatedly obtained by inserting AlSb QD layers between them. Room-temperature electron mobilities of over 10,000 $cm^2/V-s$ and 20,000 $cm^2/v-s$ can be routinely obtained on Si and GaAs substrates, respectively, after optimizing the buffer structure as well as maintaining InSb-like interface.

• Bulletin of the Korean Chemical Society
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• v.25 no.5
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• pp.617-619
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• 2004

As an pretreatment, a Fe$(NO_3)_3{\cdot}9H_2O-Al(OH)_3$mixture was ground by a high energy mill and used as a supported catalyst for the growth of carbon nanotubes by a thermal CVD. The crystal structure of the catalyst disordered by the grinding influenced significantly the synthesis of carbon nanotubes in a thermal CVD.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.37-37
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• 2008

고온에서 안정적인 DLC막을 성막하기 위해 PECVD공정에서 실리콘을 첨가하여 제조하였다. 기존의 실리콘첨가 DLC막과는 다르게 고온에서 생성됨으로 마이크로 클러스터 형태의 DLC구조로서 disordered 영역이 넓게 존재하고 있어 I(D)/I(G)비에서의 변화가 있는 것이 관찰되었다. 실리콘 양이 증가할수록 값이 낮아지는 것이 관찰되는데 이는 실리콘량이 증가하면서 수소의 위치에 실리콘이 결합하면서 sp3 단일구조형태의 코팅 막을 만드는 것이 관찰된다. 고온 어닐링효과로 내부구조에서 다량의 sp2구조가 관찰되는 것으로서 DLC막이 어느 정도 흑연화되지만, 실리콘이 SiC에서 SiOx로 $SiO_2$와 SiOH막으로 바뀌는 면서 마찰계수가 낮은 DLC막을 유지할 것으로 기대되며, XPS와 FT-IR분석에 의해 이러한 상들의 존재를 관찰할 수 있었다. 특히 공정상 TMS이 증가하면 첨가된 Si에 의해 형성되는 막이 초기부터 OH기를 다량 포함하고 있는 것을 알 수 있었고, 온도 상승에 의해서 실리콘표층에 더욱 많은 SiOx계열의 물질이 생성되는 것이 명확하게 발견되었다.

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.525-529
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• 1991

A simple route is described for the selective functionalization of calixarene at the para positions of phenyl rings. Calix[4]arene tetraacetate 2, obtained from the treatment of calix[4]arene with acetic anhydride, undergoes Fries rearrangement to yield the diametrically para substituted p-diacetylcalix[4]arene 3 in 80% yield. The crystal and molecular strucutre has been determined by X-ray diffraction method. The crystals are orthorhombic, space group Pna21, with a = 11.121 (3), b = 10.374 (3), c = 21.690 (6) $\AA$ and Z = 4. The structure was solved by direct method and refined by full-matrix least-squares methods to final R of 0.036 for 1795 observed reflections. Each hydroxyl hydrogen atom is disordered over two positions. The macrocycle exists in the cone conformation which is determined by the strong circular intramolecular flip-flop type hydrogen bonds of phenolic OH, while crystal packing effects of the diametrically para-acetyl substituents seem to be responsible for the distortion of the cone conformation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.224-230
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• 1999

Agglomeration of colloidal alumina particles in a suspension is simulated. Particles in a suspension have potential energies between them and move to decrease the summation of all the potential energies between particles. The effects of various types of potential curves on particle agglomeration were checked. Strong short range attractive energy without repulsive energy barrier makes small strong clusters with disordered network structure but weak short-range force with big repulsive energy barrier makes big agglomerates with a close packing structure. As particles are agglomerated the potential energy with strong repulsive energy barrier between agglomerates gradually decreases the importance of the repulsive energy barrier and induces a different type of agglomeration behavior.