• Journal of the Microelectronics and Packaging Society
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• v.10 no.2
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• pp.13-17
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• 2003

In this study, new LTCC materials of $ZnWO_4$-LiF system were developed for the application to RF Module fabrication. Pure $ZnWO_4$ must be sintered above $1050^{\circ}C$ in order to obtain up to 98% of full density. The measured dielectric constant ($\epsilon_r$)quality factor ($Q{\times}f0$), and temperature coefficient of resonant frequency ($\tau_f$ were 15.5, 74000 GHz, and $-70ppm^{\circ}C$, respectively. LiF addition resulted in a liquid phase formation at 81$0^{\circ}C$ due to interaction between ZnWO$_4$ and LiF. Therefore, ZnWO$_4$ with 0.5∼1.5 wt% LiF could be densified at $850^{\circ}C$. In the given LiF addition range, the sintering shrinkage increased with increasing LiF content. Addition of LiF slightly lowered the dielectric constant from 15.5 to 14.2∼15 due to lower dielectric constant of LiF. Qxfo value decreased with increasing LiF content. This can be explained in terms of the interaction between LiF and $ZnWO_4$, and inhomogeneity of grain structure.

• Nuclear Engineering and Technology
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• v.2 no.4
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• pp.269-272
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• 1970

Thermoluminescence (TL) from LiF powder of purity 99.98 ％ was accomplished and this TL intensity showed glow peaks at 12$0^{\circ}C$, 22$0^{\circ}C$ and 30$0^{\circ}C$. Sintered LiF powder which has an activation of 2％ proportion by weight of MgC1$_2$show strong increased TL and this characteristic of the glow curve was investigated precisely. LiF which is used in TL dosimetry has been known to have electrons caused by impurities such as Mg, Mn, etc. This experiment shows that Mg, one of the impurities, is definitely diffused through LiF crystals. The effects of sintering time were detected in this glow curve and it was confirmed that MgC1$_2$also has a TL effect.

• Mass Spectrometry Letters
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• v.1 no.1
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• pp.9-12
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• 2010

Trimethylboroxine (TMB) is a six-membered ring compound containing Lewis acidic boron and Lewis basic oxygen atoms that can bind halide anion and alkali metal cation, respectively. We employed Fourier transform ion cyclotron resonance spectroscopy to study the gas-phase binding of $LiBrLi^+$ and $F^-(KF)_2$ to TMB. TMB forms association complexes with both $LiBrLi^+$ and $F^-(KF)_2$ at room temperature, providing direct evidence for the ditopic binding. Interestingly, the $TMB{\cdot}F^-(KF)_2$ anion complex is formed 33 times faster than the $TMB{\cdot}Li^+BrLi$ cation complex. To gain insight into the ditopic binding of an ion pair, we examined the structures and energetics of $TMB{\cdot}Li^+$, $TMB{\cdot}F^-$, $TMB{\cdot}LiF$ (the contact ion pair), and $Li^+{\cdot}TMB{\cdot}F^-$ (the separated ion pair) using Hartree-Fock and density functional theory. Theory suggests that $F^-$ binds more strongly to TMB than $Li^+$ and the contact ion-pair binding ($TMB{\cdot}LiF$) is more stable than the separated ion-pair binding ($Li^+{\cdot}TMB{\cdot}F^-$).

• Analytical Science and Technology
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• v.13 no.6
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• pp.759-765
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• 2000

A study on the separation of Zr metal from $LiF-BeF_2-ZrF_4$ (67-27-6 mol%) molten salt was carried out using electrowinning. The decomposition potentials of the $LiF-BeF_2$ (72-28 mol%) and the $LiF-BeF_2-ZrF_4$ (67-27-6 mol%) molten salts were measured to be -1.55 and -1.35 volt, respectively. The Zr separation voltage from the salt were found to be in a range of -1.4 -1.5 volt. As increasing applied current, the deposition of molten salt on a cathode increases but the current efficiency decreases. In addition, the deposition and current efficiency decreases with increasing temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.696-700
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• 2010

We fabricated red and blue organic light emitting display (OLEDs) which had the two kinds of multi-structure of ITO/HIL/HTL/EML/ETL/LiF/Al and ITO/HIL/HTL/EML/ETL/LiF/Al/LiF. In the case of red OLED that had LiF/Al/LiF structure compared to LiF/Al structure, the current density increased from 4.3 mA/$cm^2$ to 7.3 mA/$cm^2$, and the brightness increased from 488 cd/$m^2$ to 1,023 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 11.28 cd/A to 13.95 cd/A. Also in the case of blue OLED that had LiF on Al cathode layer, the current density increased from 1.2 mA/$cm^2$ to 1.8 mA/$cm^2$, and the brightness increased from 45 cd/$m^2$ to 85 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 3.69 cd/A to 4.82 cd/A. Through these experimental results it could be suggested that the LiF layer formed on Al prevents the oxidation of Al surface, and the electrode resistance become low with increase of supplied electrons, therefore the brightness and the efficiency are improved from the influence to the well-balanced bonding of electron and hole at emitting layer.

• Nuclear Engineering and Technology
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• v.7 no.3
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• pp.191-198
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• 1975

A study was made on the neutron dosimetry in a mixed gamma-neutron field with LiF thermoluminescent dosimeter. In order to estimate the neutron dose in a mixed field, $^{6}$ LiF and $^{7}$ LiF dosimeters were used for fast and thermal neutron doses. The over-all conversion factors for the effects of dosimeter positions were derived for personnel monitoring and the glow curves of the LiF dosimeters for neutron and gamma-ray doses were also analyzed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.426-430
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• 2003

Fissionable uranium will be separated from long-lived nuclear materials in pyroprocess for transmutation. This study was measured decomposition voltage and deposition rate on cathode of uranium in $LiF-BeF_2$ molten salt by electrowinning. The result of experimental is that decomposition voltage of $UF_4$ and $LiF-BeF_2$ molten salt is -1.4 and -1.5 volt at $500^{\circ}C$ Deposition rate of uranium on cathode increases with increase of uranium concentration in molten salt.

• Analytical Science and Technology
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• v.13 no.6
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• pp.712-721
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• 2000

$LiF-BeF_2-ZrF_4$(63-30-7 mol%) molten salt was dissolved up to 0.02g in 1ml of distilled water at room temperature. $ZrO_2$ oxide made from $ZrF_4$ through pyrohydrolysis was recovered by leaching in distilled water with $LiF-BeF_2-ZrF_4$molten salt including it at room temperature. The crystalline sharpness of recovered $ZrO_2$ oxide was not damaged.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.552-558
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• 2000

LiMn2O4 thin fiolm cathodes for Li-ion secondary battery were fabricated by r.f. magnetron sputtering technique. As-deposited films were amorphous. A spinel structure could not be obtained LiMn2O4 films by in-situ thermal annealing. After post thermal annealing over $700^{\circ}C$ in oxygen atmosphere, LiMn2O4 films prepared above 100 W r.f. power could be crystallized into a spinel structure. The electrochemical property of the LiMn2O4 film cathodes was tested in a Li/1 M LiClO4 in PC/LiMn2O4 cell. From cyclic voltammetry at scan rate of 2mV/sec of 2.5~4.5V, LiMn2O4 electrode prepared by post annealing at 75$0^{\circ}C$ showed good initial capacity. LiMn2O4 electrode prepared by post annealing at 80$0^{\circ}C$ showed the best crycling performance.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.147-147
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• 2015

The multilayer structure of the organic light emitting diode has merits of improving interfacial characteristics and helping carriers inject into emission layer and transport easier. There are many reports to control hole injection from anode electrode by using transition metal oxide as an anode buffer layer, such as V2O5, MoO3, NiO, and Fe3O4. In this study, we apply thin films of LiF which is usually inserted as a thin buffer layer between electron transport layer(ETL) and cathode, as an anode buffer layer to reduce the hole injection barrier height from ITO. The thickness of LiF as an anode buffer layer is tested from 0 nm to 1.0 nm. As shown in the figure 1 and 2, the luminous efficiency versus current density is improved by LiF anode buffer layer, and the threshold voltage is reduced when LiF buffer layer is increased up to 0.6 nm then the device does not work when LiF thickness is close to 1.0 nm As a result, we can confirm that the thin layer of LiF, about 0.6 nm, as an anode buffer reduces the hole injection barrier height from ITO, and this results the improved luminous efficiency. This study shows that LiF can be used as an anode buffer layer for improved hole injection as well as cathode buffer layer.