• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.53-63
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• 2012

As a result of the economical loss caused by unusual climate changes resulting from emission of excessive green house gases such as carbon dioxide which is expected to account for 5~20% of the world GDP by 2100, researching technologies regarding the reduction of carbon dioxide emission is being favored worldwide as a part of the high value-added industry. As one of the Annex II countries of Kyoto Protocol of 1997 that should keep the average $CO_2$ emission rate of 5% by 2013, South Korea is also dedicated to the researches and industries of $CO_2$ emission reduction. In this study, Application of LiDAR data & KOMPSAT-2 satellite image for calculated forest Biomass. Raw LiDAR data's tree numbers and tree-high with field survey data resulted in 90% similarity of objects and an average of 0.3m difference in tree-high. Calculating the forest biomass through forest type information categorized as KOMPSAT-2 image and LiDAR data's tree-high data of tree enabled the estimation of $CO_2$ absorption and forest biomass of forest type, The similarity between the field survey average of 90% or higher were analyzed.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.305-310
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• 2014

This study examined the morphological changes in lithium surface immersed in 1mol $dm^{-3}$ (M) $LiPF_6 $ dissolved in propylene carbonate (PC) containing different 1,2-dimethoxyethane (DME) concentrations as a co-solvent. A passivation film was formed on the surface of lithium metal by electrolyte decomposition. The passivation film formation reactions were significantly affected by the amount of co-solvent, DME, in electrolyte solution. A stable film was obtained from the 1 M $LiPF_6 $ / PC:DME (67:33) solution in which lithium electrode showed good electrochemical performances. Atomic force microscope (AFM) and electrochemical impedance spectroscopy (EIS) results revealed that there were no direct correlations between changes in the surface morphology of lithium metal and the resistance behavior of its passivation film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.452-452
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• 2009

HEV용 리튬 이차전지의 양극물질로서 $LiMn_2O_4$는 일반적으로 사용되고 있는 $LiCoO_2$에 비해 값이 저렴하고 독성이 낮으며, 높은 전압과 좋은 율 특성을 갖는 물질이다. 하지만 고온에서 전이금속인 Mn이 전해액으로 용출되어 급격한 용량감소로 인한 짧은 수명의 단점을 가지고 있다. 흔히 전구체로 쓰이는 $MnO_2$, $Mn_3O_4$, MnOOH등은 전기 분해법을 이용한 EMD가 주로 이용된다. 본 연구에서는 출발 물질로 $KMnO_4$와 $Mn(NO_3)_2$를 수용액 반응을 시켜서 농도, 온도변화에 따른 입자 형상 및 크기와 결정상의 변화를 관찰하고, 화학적 방법으로 얻어진 $MnO_2$와 LiOH를 합성하여 각각의 $LiMn_2O_4$를 비교 분석하고자한다.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.223-230
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• 2019

A facile method for surface coating with $Li_2TiF_6$ which has a high lithium-ion conductivity, on $LiMn_2O_4$ spinel cathode material for high performance lithium ion batteries. The surface coating is performed by using a co-precipitation method with $Li_2CO_3$ powder and $H_2TiF_6$ solution under room temperature and atmospheric pressure without special equipment. Total coating amount of $Li_2TiF_6$ is carefully controlled from 0 to 10 wt.% based on the active material of $LiMn_2O_4$. They are evaluated by a systematic combination of analyses comprising with XRD, SEM, TEM and ICP. It is found that the surface modification of $Li_2TiF_6$ is very beneficial to high cycle life and excellent rate capability by reducing surface failure and supporting lithium ions transportation on the surface. The best coating condition is found to have a high cycle life of $103mAh\;g^{-1}$ at the 100th cycle and a rate capability of $102.9mAh\;g^{-1}$ under 20 C. The detail electrochemical behaviors are investigated by AC impedance and galvanostatic charge and discharge test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.196-199
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• 2000

마이크로파용 세라믹 유전체로 사용되는 MgTiO$_3$-CaTiO$_3$계 유전체에 Li을 첨가하여 이때 얻어지는 마이크로파 유전특성과 소결특성에 대하여 알아보았다. 94MgTiO$_3$-6CaTiO$_3$으로 주조성을 고정시키고 여기에 Li$_2$CO$_3$를 Li원자 기준으로 0 ~ 10 mol% 범위 안에서 첨가하여 1200~140$0^{\circ}C$의 온도에서 4시간 소결하였다. Li의 첨가량이 적을 때에는 유전체의 품질계수와 유전상수가 모두 감소하였으나 약 lmol% 이상 되면 다시 증가하였으며, 이후 첨가량이 과도해지면 다시 서서히 감소하는 경향을 볼 수 있었다. 1.0 ~ 3.0 mol%의 첨가량 범위 안에서 Li은 MgTiO$_3$-CaTiO$_3$계 유전체의 품질계수를 증가시켜주는 역할을 하는 것으로 나타났다 1.5mol%의 Li을 첨가하고 1275$^{\circ}C$에서 4시간 소결한 시편에서 유전상수는($\varepsilon$$_{r}$) 20.0, Qf는 78,000 그리고 공진주파수 온도계수($\tau$$_{f}$)는 -1.6ppm/$^{\circ}C$의 결과를 얻을 수 있었다.다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.781-785
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• 2016

With trend of the miniaturization and the high-functionalizing of mobile communication system, low-loss microwave dielectric materials are widely used for high frequency communication components. These dielectric materials should be co-sintered with highly electric-conducting metal such as silver or copper for high-frequency and thick film process application. Sintering temperature of $Ca(Li_{1/3}Nd_{2/3})_{0.2}Ti_{0.8}]O_{3-{\delta}}$, which has excellent dielectric properties such as ${\varepsilon}_r$ above 40, quality factor ($Q{\cdot}f_0$) above 16,000 GHz, and TCF (temperature coefficient of resonant frequency) of $-20{\sim}-10ppm/^{\circ}C$, is reported as high as $1,175^{\circ}C$, so it could not be co-sintered with silver or copper. Therefore in this study, low-temperature melting glasses of Zn-B-O and Zn-B-Si-O systems were added to $Ca[(Li_{1/3}Nb_{2/3})_{0.8}Ti_{0.2}]O_{3-{\delta}}$ to lower its sintering temperature under $900^{\circ}C$ without losing excellency of dielectric properties. With 15 weight % of Zn-B-Si-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.11g/cm^3$, ${\varepsilon}_r$ of 40.1, $Q{\cdot}f_0$ of 4,869 GHz, and TCF of $-5.9ppm/^{\circ}C$. With 15 weight % of Zn-B-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.14g/cm^3$, ${\varepsilon}_r$ of 40.4, $Q{\cdot}f_0$ of 7,059 GHz, and TCF of $-0.92ppm/^{\circ}C$.

• The Magazine of the IEIE
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• v.34 no.12
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• pp.38-48
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• 2007

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.3
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• pp.242-248
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• 2002

SnCo alloy powder prepared by high energy ball milling is examined as an anode material for lithium-ion batteries. As the ball-milling time increased, the crystallinity of SnCo decreased. XRD and TEM SADP showed that nanocrystalline and amorphous phase coexisted after 16 h ball-milling. As the crystallinity decreased, the cycleability increased. At first cycle, there are 4 plateau potentials. The observation of voltage plateau at about 0.68 V confirms the formation of Sn-Li alloy and Co metal. It is considered that The plateau potentials below 0.68 V were reaction between Li and Sn. The change of chemical diffusion coefficient showed that the structure of SnCo alloy abruptly changed at first cycle, and maintained after 2nd cycle.

• Polymer(Korea)
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• v.24 no.6
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• pp.886-892
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• 2000

Poly(4-vinyl phenol) (PVPh) was neutralized by LiOH and PVPh ionomers (PVPh-Li) with different Li neutralization extents were synthesized. The variation in $T_{g}$ with Li neutralization was determined by DSC and the results show that the $T_{g}$ increases by 3.$8^{\circ}C$ per Li mol%. When comparing this result with the 3.$2^{\circ}C$ per Na mol% reported for poly (styrene-co-hydroxy styrene), the greater value for PVPh-Li may be due to a strong interaction between unneutralized free -OH and -OLi produced. No distinct small angle X-ray scattering (SAXS) peak was observed for these PVPh ionomers in bulk. In the 50/50 blend of PVPh-Li with PVPh, the miscibile blend was obtained when the Li neutralization in PVPh-Li was 10 mol%. On the contrary, the 50/50 PVPh-Li/PMMA was immiscible when the Li neutralization was 5 mol%. It can be concluded that, even if the starting blend is miscible owing to hydrogen bonding, the miscibility of blend becomes diminished by introducing small amount of ion groups into one of the constituent polymers and the blend can be immiscible as long as any new strong intermolecular ion-dipole interaction is not generated.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1325-1332
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• 2023

Recently, much research is being conducted based on point cloud data for the growth of innovations such as construction automation in the transportation field and virtual national space. This data is often measured through remote control in terrain that is difficult for humans to access using devices such as UAVs and UGVs. Drones, one of the UAVs, are mainly used to acquire point cloud data, but photogrammetry using a vision camera, which takes a lot of time to create a point cloud map, is difficult to apply in construction sites where the terrain changes periodically and surveying is difficult. In this paper, we developed a point cloud mapping system by adopting non-repetitive scanning LiDAR and attempted to confirm improvements through field application. For accuracy analysis, a point cloud map was created through a 2 minute 40 second flight and about 30 seconds of software post-processing on a terrain measuring 144.5 × 138.8 m. As a result of comparing the actual measured distance for structures with an average of 4 m, an average error of 4.3 cm was recorded, confirming that the performance was within the error range applicable to the field.