• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.1-10
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• 1979

An inclusion forming virus isolated from a fan webworm, Hyphantria cunea, in 1975 was identified as a nuclear polyhedrosis virus. With the virus isolated in Korea, it was considered that the virus would be one of the valuable microorganism in microbial control. In this connection, 1) the shape and size of the virus for identification, 2) susceptibility of the various instar larvae to the virus, 3) the effects of storage condition on the pathogenicity and the cross infection of the virus to the larvae of Bombyx mori were examined. The results are summarized as follows; 1. The polyhedron was tetrahedron or hexahedron of $2\mu$ in size and the rod-shaped virus particles consisting of $2\~14$ rods in a bundle were $330m{\mu}\times35m{\mu}$ in size. 2. The hexagonal nuclear polyhedra were found only in the nucleus of the midgut cells but were variable in size. 3. The $LD_{50}$ values for the various instar larvae of H. cunea were $8.377\times10^4\;PIBs/ml$ for the second, $4.974\times10^5\;PIBs/ml$ for the fifth instar larvae. The $LT_{50}values$ for $10^6\;PIBs/ml$ were 9.6 days for the second, 11.5 days for the third, 12.0 days for the fourth and 17 days for the fifth instar larvae. 4. The susceptibility of H. cunea to the nuclear polyhedrosis virus was greater in the first generation than in the second generation. 5. The effect of the storage conditions on the pathogenicity of the nuclear polyhedra was less in refrigerator $(5^{\circ}C)$ and in freezing $(-80^{\circ}C)$ than in room temperature $(18.5^{\circ}C)$, especially as air-dried polyhedra than as suspension. The pathogenicity of the polyhedra seemed to decrease by sunlight during storage as cadavers, since rather greater decrease in pathogenicity was found in sunny condition than in shady condition. 6. The effective spray concentration was $6.4\times10^7\;PIBs/ml$ in the field and its $LT_50$ values for the third and the fifth instar larvae were 4.8 days and 14.2 days, respectively. 7. No cross infections were found in the nuclear polyhedrosis virus between H. cunea and B. mori. larvae.

• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.7-12
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• 2017

Using a precursor of $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ as a starting material, a surface-modified cathode material was obtained by coating with KCl, where the added KCl reduces residual Li compounds such as $Li_2CO_3$ and LiOH, on the surface. The resulting electrochemical properties were investigated. The amounts of $Li_2CO_3$ and LiOH decreased from 8,464 ppm to 1,639 ppm and from 8,088 ppm to 6,287 ppm, respectively, with 1 wt% KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ that had been calcined at $800^{\circ}C$. X-ray diffraction results revealed that 1 wt% of KCl added $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ did not affect the parent structure but enhanced the development of hexagonal crystallites. Additionally, the charge transfer resistance ($R_{ct}$) decreased dramatically from $225{\Omega}$ to $99{\Omega}$, and the discharge capacity increased to 182.73mAh/g. Using atomic force microscopy, we observed that the surface area decreased by half because of the exothermic heat released by the Li residues. The reduced surface area protects the cathode material from reacting with the electrolyte and hinders the development of a solid electrolyte interphase (SEI) film on the surface of the oxide particles. Finally, we found that the introduction of KCl into $LiNi_{0.6}Co_{0.2}Mn_{0.2}O_2$ is a very effective method of enhancing the electrochemical properties of this active material by reducing the residual Li. To the best of our knowledge, this report is the first to demonstrate this phenomenon.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.310-310
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• 2014

ZnO박막은 넓은 밴드갭 (3.37 eV), 높은 여기 결합 에너지 (60 meV)를 가지는 육방정계 우르자이트(hexagonal wurtzite) 결정구조를 가지는 II-VI족 화합물 반도체로, 가시광선 영역에서의 높은 광학적 투과도 특성과 자외선 파장에서 발광이 가능한 장점을 가진다. 최근, ZnO박막 성장 기술이 상당히 발전하였지만, 아직까지도 p-형 ZnO박막 성장 기술은 충분히 발전하지 못하여 ZnO의 동종접합 LED는 아직 상용화되지 않고 있는 실정이다. 따라서, 많은 연구 그룹에서 p-GaN, p-SiC, p-diamond, p-Si 등과 같은 p-type 물질 위에 n-type ZnO를 성장시킨 이종접합 다이오드가 연구되고 있다. 특히, p-GaN의 경우 ZnO와의 격자 불일치 정도가 1.8 % 정도로 작다는 장점이 있어 많은 연구가 이루어 지고 있다. 일반적으로 c-축을 기반으로 한 극성ZnO 발광다이오드에서는 자발 분극과 압전 분극 현상에 의해 밴드 휨 현상이 발생하고, 이로 인해 전자와 정공의 공간적 분리가 발생하게 되어 발광 재결합 효율이 제한되고 있다는 문제가 발생한다. 따라서, 본 연구에서는 극성 (0001) 및 비극성 (10-10) n-ZnO/p-GaN 발광다이오드의 성장 및 발광 소자의 전기 및 광학적 특성에 대한 비교 연구를 진행하였다. 금속유기 화학증착법을 이용하여 c-면과 m-면 위에 각각 극성 (0001) 및 반극성 (11-22) GaN박막을 $2.0{\mu}m$ 성장시킨 후 Mg 도핑을 한 p-GaN을 $0.4{\mu}m$ 성장시켜 각각 극성 (0001) 및 반극성 (11-22) p-GaN템플릿을 준비하였다. 이후, N2분위기 $700^{\circ}C$에서 3분동안 열처리를 통하여 Mg 도펀트를 활성화시킨 후 원자층 증착법을 이용하여 동시에 극성 및 반극성 p-GaN의 위에 n-ZnO를 $0.11{\mu}m$ 성장시켜 이종접합구조의 발광소자를 형성하였다. 이때, 극성 (0001) p-GaN 위에는 극성의 n-ZnO 박막이 성장되는 반면, 반극성 (11-22) p-GaN 위에는 비극성 (10-10) n-ZnO 박막이 성장됨을 HR-XRD로 확인하였다. 극성 (0001) n-ZnO/p-GaN이종접합 발광다이오드의 전계 발광 스펙트럼에서는 430 nm 와 550 nm의 두 피크가 동시에 관찰되었다. 430 nm 대역의 파장은 p-GaN의 깊은 준위에서 발광하는 것으로 판단되며, 550 nm 피크 영역은 ZnO의 깊은 준위에서 발광되는 것으로 판단된다. 특히, 10 mA 이하의 저전류 주입시 550 nm의 피크는 430 nm 영역보다 더 큰 발광세기를 나타내고 있다. 하지만, 10 mA 이상의 전류주입 하에서는 550 nm의 영역보다 430 nm의 발광세기가 더욱 증가하는 것을 확인할 수 있었다. 이것은 ZnO의 밴드갭이 3.37 eV로 GaN의 밴드갭인 3.4 eV다 작기 때문에 우선적으로 ZnO의 깊은 준위에서 발광하는 550 nm가 더욱 우세하지만, 지속적으로 전류주입 증가에 따른 캐리어 증가시 n-ZnO에서 p-GaN로 전자가 넘어가며 p-GaN의 깊은 준위인 430 nm에서의 피크가 우세해지는 것으로 판단된다. 반면에, 비극성 (10-10) n-ZnO/반극성 (11-22) p-GaN 구조의 이종접합 발광다이오드로 전계 발광 스펙트럼에서는 극성 (0001) n-ZnO/p-GaN에 비하여 매우 낮은 전계 발광 세기를 나타내고 있다. 이는, 극성 n-ZnO/p-GaN에 비하여 비극성 n-ZnO/반극성 p-GaN의 결정성이 상대적으로 낮기 때문으로 판단된다. 또한, 20 mA 영역에서도 510 nm의 깊은 준위와 430 nm의 발광이 관찰되었다. 동일한 20 mA하에서 두 피크의 발광세기를 비교하면 430 nm의 영역은 극성 n-ZnO/p-GaN에 비하여 매우 낮은 값을 나타내고 있다. 이는 반극성 (11-22) p-GaN의 경우 극성 (0001) p-GaN에 비하여 우수한 p-형 특성에 기인한 것으로 판단된다.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.74-84
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• 2004

Purpose: Since I-125 emits low energy (27-35 keV) radiation, thinner crystal and collimator could be employed and, hence, it is favorable to obtain high quality images. The purpose of this study was to derive the optimized parameters of I-125 SPECT using a new simulation tool, GATE (Geant4 Application for Tomographic Emission). Materials and Methods: To validate the simulation method, gamma camera developed by Weisenberger et al. was modeled. Nal(T1) plate crystal was used and its thickness was determined by calculating detection efficiency. Spatial resolution and sensitivity curves were estimated by changing variable parameters for parallel-hole and pinhole collimator. Peformances of I-125 SPECT equipped with the optimal collimator were also estimated. Results: in the validation study, simulations were found to agree well with experimental measurements in spatial resolution (4%) and sensitivity (3%). In order to acquire 98% gamma ray detection efficiency, Nal(T1) thickness was determined to be 1 mm. Hole diameter (mm), length (mm) and shape were chosen to be 0.2:5:square and 0.5:10:hexagonal for high resolution (HR) and general purpose (GP) parallel-hole collimator, respectively. Hole diameter, channel height and acceptance angle of pinhole (PH) collimator were determined to be 0.25 mm, 0.1 mm and 90 degree. The spatial resolutions of reconstructed image of the I-125 SPECT employing HR:GP:PH were 1.2:1.7:0.8 mm. The sensitivities of HR:GP:PH were 39.7:71.9:5.5 cps/MBq. Conclusion: The optimal crystal and collimator parameters for I-125 Imaging were derived by simulation using GATE. The results indicate that excellent resolution and sensitivity imaging is feasible using I-125 SPECT.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.35-42
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• 2006

Experimental study was conducted to identify the active agent for reductive dechlorination of TCE in cement/Fe(II) systems. Several potential materials-hematite (${\alpha}-Fe_2O_3$), lepidocrocite (${\gamma}$-FeOOH), akaganeite (${\beta}$-FeOOH), ettringite ($Ca_6Al_2(SO_4)_3(OH)_{12}$)-that are cement components or parts of cement hydrates were tested if they could act as reducing agents by conducting TCE degradation experiments. From the initial degradation experiments, hematite was selected as a potential active agent. The pseudo-first-order degradation rate constant ($k\;=\;0.637\;day^{-1}$) for the system containing 200 mM Fe(II), hematite and CaO was close to that ($k\;=\;0.645\;day^{-1}$) obtained from the system containing cement and 200 mM Fe(II). CaO, which was originally added to simulate pH of the cement/Fe(II) system, was found to play an important role in degradation reactions. The reactivity of the hematite/CaO/Fe(II) system initially increased with increase of CaO dosage. However, the tendency declined in the higher CaO dosage region, implying a saturation type of behavior. The SEM analysis revealed that the hexagonal plane-shaped crystals were formed during the reaction with increasing degradation efficiency, which was brought about by increasing the CaO dosage. It was suspected that the crystals could be portlandite or green rust ($SO_4$) or Friedel's salt. The XRD analysis of the same sample identified the peaks of hematite, magnetite/maghemite, green rust ($SO_4$). Either instrumental analysis predicted the presence of the green rust ($SO_4$). Therefore, the green rust ($SO_4$) would potentially be a reactive agent for reductive dechlorination in cement/Fe(II) systems.

• Journal of the Mineralogical Society of Korea
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• v.16 no.4
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• pp.333-339
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• 2003

A new mineral, Zn analogue of rancieite (Chimooite), has been discovered at the Dongnam mine, Korea. It occurs as compact subparallel fine­grained flaky or acicular aggregates in the massive manganese oxide ores which were formed by supergene oxidation of rhodochrosite­sulfide ores in the hydrothermal veins trending NS­N25E and cutting the Pungchon limestone of the Cambrian age. The flakes of chimooite are 0.2 mm for the largest one, but usually less than 0.05 mm. The acicular crystals are elongated parallel to and flattened on (001). This mineral shows gradation to rancieite constituting its marginal part, thus both minerals are found in one and the same flake. Color is bluish black, with dull luster and brown streak in globular or massive aggregates. Cleavage is perfect in one direction. The hardness ranges from 2.5 to 4. Under reflected light it is anisotropic and bireflectant. It shows reddish brown internal reflection. Chemical analyses of different parts of both minerals suggest that rancieite and chimooite constitute a continuous solid solution series by cationic substitution. The empirical chemical formula for chimooite has been calculated following the general formula, $R_2_{x}$ M $n^{4+}$$_{9­x}$ $O_{18}$ $.$n$H_2O$ for the 7 $\AA$ phyllomanganate minerals, where x varies from 0.81 to 1.28 in so far studied samples, thus averaging to 1.0. Therefore, the formula of Zn­rancieite is close to the well­known strochiometric formula $_Mn_4^{4+}$ $O_{9}$ $.$4$H_2O$. The mineral has the formula (Z $n_{0.78}$N $a_{0.15}$C $a_{0.08}$M $g_{0.01}$ $K_{0.01}$)(M $n^{4+}$$_{3.98}$F $e^{3+}$$_{0.02}$)$_{4.00}$ $O_{9}$ $.$3.85$H_2O$, thus the ideal formula is (Zn,Ca)M $n^{4+}$$_4$ $O_{9}$ $.$3.85$H_2O$. The mineral has a hexagonal unit ceil with a=2.840 $\AA$ c=7.486 $\AA$ and a : c = 1 : 2.636. The DTA curve shows endothermic peaks at 65, 180, 690 and 102$0^{\circ}C$. The IR absorption spectrum shows absorption bands at 445, 500, 1630 and 3400 c $m^{1}$. The mineral name Chimooite has been named in honour of late Prof, Chi Moo Son of Seoul National University.ity.versity.ity.y.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.538-543
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• 2008

Recently a nano-scale diamond is possible to manufacture forms of powder(below 100 nm) by new processing of explosion or deposition method. Using a sintering of nano-scale diamond is possible to manufacture of grinding tools. We have need of a processing development of coated uniformly inorganic to prevent an abnormal grain growth of nano-crystal and bonding obstacle caused by sintering process. This paper, in order to improve the sintering property of nano-scale diamond, we coated ZnO thin films(thickness: $20{\sim}30\;nm$) in a vacuum by ALD(atomic layer deposition) Economically, in order to deposit ZnO all over the surface of nano-scale diamond powder, we used a new modified fluidized bed processing replaced mechanical vibration effect or fluidized bed reactor which utilized diamond floating owing to pressure of pulse(or purge) processing after inserted diamond powders in quartz tube(L: 20 mm) then closed quartz tube by porosity glass filter. We deposited ZnO thin films by ALD in closed both sides of quartz tube by porosity glass filter by ALD(precursor: DEZn($C_4H_{10}Zn$), reaction gas: $H_2O$) at $10^{\circ}C$(in canister). Processing procedure and injection time of reaction materials set up DEZn pulse-0.1 sec, DEZn purge-20 sec, $H_2O$ pulse-0.1 sec, $H_2O$ purge-40 sec and we put in operation repetitive 100 cycles(1 cycle is 4 steps) We confirmed microstructure of diamond powder and diamond powder doped ZnO thin film by TEM(transmission electron microscope) Through TEM analysis, we confirmed that diamond powder diameter was some $70{\sim}120\;nm$ and shape was tetragonal, hexagonal, etc before ALD. We confirmed that diameter of diamond powders doped ZnO thin film was some $70{\sim}120\;nm$ and uniform ZnO(thickness: $20{\sim}30\;nm$) thin film was successfully deposited on diamond powder surface according to brightness difference between diamond powder and ZnO.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.85-97
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• 2010

This research studied the location and the spatial composition of Pihyang-jeong zone. Pihyang-jeong is regarded as one of the five great pavilions in Chollabuk-do. Located in Taein-myeon of Jeongeup-si, Pihyang-jeong is also called as 'the number one pavilion in Honam area'. 1. There is no record regarding the first construction of Pihyang-jeong. There is only transmitting by word of mouth that the scholar Choi Chi-won had an excursion to here and composed some poetry during the age of King Heon-gang of Shilla dynasty. However, there are records that Lee Ji-gweng had expanded the humble structure in 1618, Park Sung-go repaired it in 1664 and Yoo Geun repaired it again in 1715. 2. The location of Pihyang-jeong is 'high in north and low in south' and typical 'mountain in rear and water in front'. It has Seong-hwang Mountain(189m) in the north, Hang-ga Mountain(106m) in the south, Tae Mountain(33m) in the south and an open field in the northwest. 3. The spatial composition around Pihyang-jeong is as following. Pihyang-jeong faces 'Hayeonji'(the lower side lotus pond) in the south-south-west direction. 4. The buildings around Pihyang-jeong are; Pihyang-jeong, which was the pavilion of the government official not directly in charge of government office, Hambyeok-lu in the Hayeonji and the facility for the caretaker. Pihyang-jeong is a rectangular building with double eaves and hipped-and-gabled roof. It has five rooms in the front and four rooms in the side. Hambyeok-lu had been first built in 1918 as two-storey wooden pavilion with dancheong, traditional multicolored paintwork on wooden buildings. Then it was modified into rectangular single-storey pavilion with hipped-and-gabled roof and five rooms in 1971. In 2010, it was rebuilt as a hexagonal pavilion; therefore, the present shape is completely different one from the original shape. 5. The scenic features around Pihyang-jeong are as following. There are 21 stone monuments in Pihyang-jeong zone. The fence surrounding Pihyang-jeong is a traditional Korean style crude stone fence. There are three gates in three-gates-style, each gate made with two posts and one 'matbae'(gabled) roof. Also, a stepping stone for mounting/dismounting was found in the east of Pihyang-jeong outer perimeter. 6. The water scenic feature around Pihyang-jeong is a representative case of drawing in the water from the natural pond nearby government office and building a pavilion around the water. 7. The planting around Pihyang-jeong is as following. There are Zelkova trees in the boundary perimeter. In the southern small park, there are Zelkova trees, Crape-myrtie trees, Bushy young pine trees, Pine trees, Satuki, Purple azalea and Grass field. Around Hambyeok-lu in the Ha-yeonji, Elm trees, Zelkova trees and Pine trees are growing in good condition.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.101-108
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• 1993

$TiO_{2}$/Se : Te heterojunction for color sensor has been fabricated by RF reactive sputtering and thermal evaporation methods onto glass substrate. The optimum deposition condition of $TiO_{2}$ films was such that RF power was 120 W, substrate temperature was $100^{\circ}C$, oxygen concentration was 50%, working pressure was 50 mTorr for the $TiO_{2}$ film thickness of $1000{\AA}$. In this case, the optical transmittance of $TiO_{2}$ film at 550 nm-wavelength was 85%, resistivity was $2{\times}10^9{\Omega}{\cdot}cm$, refractive index was 2.3, and optical bandgap was 3.58 eV. The composition ratio of 0 to Ti by AES analysis was 1.7. When $TiO_{2}$ films were annealed at $400^{\circ}C$ for 30 min. in $O_{2}$ ambient, the optical transmittance of $TiO_{2}$ films at the wavelength range of $300{\sim}580$ nm was improved from 0 to 25%. When Se : Te films were annealed at $190^{\circ}C$ for 1 min., photosensitivity under illumination of 1000 lux was 0.75. The optical bandgap of Se : Te films was 1.7 eV. The structures of Se : Te films were the hexagonal with (100) and (110) orientation. The spectral response of a-Se was improved by the addition of Te, especially in the long wavelength region. The $TiO_{2}$/Se : Te heterojunction showed wide spectral response, and more improved one than that of a-Si film in the blue light region.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.313-325
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• 2007

In order to have better insights into adsorption of organic molecules on kaolinite surfaces, we performed quantum chemical calculations of interaction between three different model clusters of kaolinite siloxane surfaces and benzyl alcohol, with emphasis on the effect of size and lattice topology of the cluster on the variation of electron density and magnetic shielding tensor. Model cluster 1 is an ideal silicate tetrahedral surface that consists of 7 hexagonal rings, and model cluster 2 is composed of 7 ditrigonal siloxane rings with crystallographically distinct basal oxygen atoms in the cluster, and finally model cluster 3 has both tetrahedral and octahedral layers. The Mulliken charge analysis shows that siloxane surface of model cluster 3 undergoes the largest electron density transfer after the benzyl alcohol adsorption and that of model cluster 1 is apparently larger than that of model cluster 2. The difference of Mulliken charges of basal oxygen atoms before and after the adsorption is positively correlated with hydrogen bond strength. NMR chemical shielding tensor calculation of clusters without benryl alcohol shows that three different basal oxygen atoms (O3, O4, and O5) in model cluster 2 have the isotropic magnetic shielding tensor as $228.2{\pm}3.9,\;228.9{\pm}3.4,\;and\;222.3{\pm}3.0ppm$, respectively. After the adsorption, the difference of isotropic chemical shift varies from 1 to 5.5 ppm fer model cluster 1 and 2 while model cluster 2 apparently shows larger changes in isotropic chemical shift. The chemical shift of oxygen atoms is also positively correlated with electron density transfer. The current results show that the adsorption of benzyl alcohol on the kaolinite siloxane surfaces can largely be dominated by a weak hydrogen bonding and electrostatic force (charge-charge interaction) and demonstrate the importance of the cluster site and the lattice topology of surfaces on the adsorption behavior of the organic molecules on clay surfaces.