• 한국재료학회지
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• 제8권3호
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• pp.268-273
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• 1998

Zircaloy-4 합금판재에 230-250ppm의 수소를 장입시키고 $400^{\circ}C$에서 72시간동안 균질하게 수소화물을 형성시킨후 $350^{\circ}C$의 static autoclave를 이용하여 여러 가지 농도의 LiOH 부식용액조건에서 부식시험을 수행하였다. 부식평가는 시간에 따른 무게증가의 변화로서 측정하였고, 시편의 미세구조는 광학현미경과 주사전자현미경을 사용하여 관찰하였다. 부식시험 후 형성된 산화막에서의 H와 Li의 분포를 확인하기 위해 secondary ion mass spectrometry(SIMS)를 이용해 각 원소의 분포를 두께방향에서 측정하였다. 여러 가지 농도의 LiOH 수용액조건에서 Li+ 이온의 용액농도가 30ppm 이상으로 증가하면 합금의 부식은 급격히 가속화되었다. 이것은 $Li^{+}$가 산화막 내의 $Zr^{4+}$ 자리를 치환함에 따라 산소공공이 증가로 산화반응이 증가되고, 이로 인해 형성되는 수소화물의 양이 증가하기 때문이다. LiOH용액조건에서 부식시험 전에 시편 내에 수소를 장입시켜 수소화물을 형성시키면 수소를 장입하지 않은 시편보다 부식이 더 빨리 가속되지만, 시험기간이 길어지면 오히려 수소를 미리 장입시키지 않은 시편의 부식속도가 더 빨라진다. 이것은 부식시험 전에 수소를 시편에 미리 장입을 시키면 이때 형성된 수소화물에 의해 초기에 부식이 빨리 가속되지만 이미 고용도 이상의 수소가 금속 내부에 존재하므로 부식과정 중에 생기는 수소가 금속의 내부로 확산되어 들어오는 것이 억제되어 부식속도가 둔화되는 것으로 생각된다.

• Applied Biological Chemistry
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• 제2권
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• pp.45-52
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• 1961

The decomposition of malathion in dust for mulations prepared from four Korean tales as carriers during storage period has been studied. Amberlite CG-120, a cation exchange resin . which has higher cation exchange capacity than tales, was also used as a carrier in hope of finding out the effect of nagative charge upon the decomposition of malathion. Besides the original talc powders obtained directly from the mines, the hydrogen ion saturated forms were also used as carriers for comparisonal study. The saturated ions for the resin were hydrogen, sodium and magnesium. As the physical properties of the tales, colloid content, water adsorption capacity, PH, specific surface, phosphate fixing capacity and exchangeable canons were determined, and these properties were correlated with the amount of the decomposition. Following results were obtained from the experiment. 1. The malathion in the talc in dust was found to decompose around 10-15% ofthe total withina month. About 50% of the decom position that took place after a month was found to occur within a week. 2. The resin which has higher cation exchange capacity than the tales was highly effective in the decomposition of malathion compared with the tales. 3. In every case the saturation of the exchange complexes with hydrogen ion greatly accelerated the decomposition of malathion. 4. The most highly correlated physical properties with the decomposition were colloid content and specific surface of the tales. 5. The water adsorption and phosphate fixing capacities of the tales were found not to correlate with the amount of malathion decomposed. From the experimental results it was concluded that the active negative spots on the colloidal tales or the resin attract the electropositive phosphorus atom in a malathion molecule thereby inducing the decomposition easier. The presence of hydrogen ion nearby might cause a catalytic effect in the decomposition of malathion.

• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.69-72
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• 1987

The structures of dehydrated $Ag_9Cs_3$-A treated with hydrogen gas at three different temperatures have been determined by single-crystal X-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at 23(1) $^{\circ}C$. All crystals were ion exchanged in flowing streams of aqueous $AgNO_3$/$CsNO_3$ with a mole ratio 1:3.0 to achieve the desired crystal composition. The structures treated with hydrogen at $23^{\circ}C(a=12.288(1)\;{\AA})\;and\;310^{\circ}C(a=12.291(2)\;{\AA})$ refined to the final error indices R1 = 0.091 and R2 = 0.079, and 0.065 and 0.073, respectively, using the 216 and 227 reflections, respectively, for which I >3${\sigma}$(I). In both of these structures, eight $Ag^+$ ions are found nearly at 6-ring centers, and three $Cs^+$ ions lie at the centers of the 8-rings at sites of $D_{4h}$ symmetry. One $Ag^{\circ}atom$, presumably formed from the reduction of a $Ag^+$ ion by an oxide ion of a residual water molecule or of the zeolite framework during the dehydration process, is retained within the zeolite, perhaps in a cluster. In these two structures hydrogen gas could not enter the zeolite to reduce the $Ag^+$ ions because the large $Cs^+$ ions blocked all the 8-windows. However, hydrogen could slowly diffuse into the zeolite and was able to reach and to reduce about half of the $Ag^+$ ions in the structure only at high temperature ($470^{\circ}C$). The silver atoms produced migrated out of the zeolite framework, and the protons generated led to substantial crystal damage.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제16회 학술발표회 논문개요집
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• pp.60-60
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• 1999

• 한국환경보건학회지
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• 제27권1호
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• pp.1-7
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• 2001

Ammonia is used in the manufacture of fertilizers, refrigerants, stabilizers and many household cleaning agents. These wide applications resulted in ammonia contamination in water. Ammonia can be removed from water by physical, biological, and chemical methods. Ozonation is effictive in the treatment of water with low concentration of ammonia. This study is undertaken to provide kinetic data for the ozonation of ammonia with or without hydrogen peroxide. The results were as follows; The destruction rate of ammonia increased gradually with the influent hydrogen peroxide concentration up to 0.23 mM and inhibited in the range of 0.23~11.4mM, and the maximum removal rate of ammonia achieved at 0.23mM of hydrogen peroxide, and the overall kinetics was first order. The combination effect of hydrogen and ozone to oxide ammonia in aqueous solution was better than ozone alone. The reacted ammonia was converted completely to nitrate ion.

• 한국수소및신에너지학회논문집
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• 제12권1호
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• pp.51-63
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• 2001

In this paper molecular dynamics simulations were employed to investigate the structural and dynamic properties of hydrogen ions impacted on the Ni (100) surface with the $45^{\circ}$ incident angle. The initial kinetic energies of the hydrogen ion range from 100 to 1,600 eV. Together with the trajectory visualization of hydrogen ions, we computed scattering and penetration yields, mean energies and angles, and probability and energy distributions as a function of longitudinal and azimuthal directions. In the case of lower energy scattering ions, the multiple collision effects were found to be important to the third layers or lower. For higher energy penetrating ions, compared with the normal incident angle, it was significant the effective channeling effects through the Ni layers and the angle dependencies were indicated both in the longitudinal and the azimuthal angle directions.

• 한국응용과학기술학회지
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• 제29권2호
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• pp.278-285
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• 2012

낮은 농도와 높은 농도의 염 용액에서 Poly(styrene sulfonic acid)(PSSA) 겔의 팽윤도에 대한 이온 특성화 효과를 ${SO_3}^-$와 페닐 고리의 수소결합을 통하여 조사하였다. 낮은 농도에서 PSSA 수화 겔의 수축 정도는 ${SO_3}^-$와 물 사이의 수소 결합에 대한 음이온의 불안정화 영향 때문에 음이온에서는 $SCN^-$<$Br^-$<$Cl^-$<$F^-$의 순서를 따랐다. 재 팽윤은 계에서 특별한 상호 작용이 있을 때 높은 농도에서 관찰되었다. 반면 양이온에서 PSSA 겔의 수축은 $Li^+$<$Na^+$<$K^+$<$Ca^{+2}$ 순서를 따랐다. $Ca^{+2}$ 이온에서의 큰 수축 효과는 이가 양이온(+2)에 의한 PSSA 겔의 물리적 가교 때문에 나타난 것으로 보인다. 양이온에서의 수축은 ${SO_3}^-$와 양이온 사이의 상호작용 정도에 비례하였다. PSSA의 팽윤에 대한 이온 특성화 효과는 ${SO_3}^-$와 페닐 고리의 수화 수소결합에 대한 이온의 영향 정도, 양이온과 ${\pi}$ 전자의 상호작용, 소수성 상호작용, 그리고 분산력 등이 복합적으로 작용하여 나타난다고 볼 수 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.179.2-179.2
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• 2013

A large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER device. Negative hydrogen ion sources are major components of neutral beam injection (NBI) systems in future large-scale fusion experiments such as ITER and DEMO. The RF sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck-Institute for Plasma Physics), Garching, for the ASDEX-U and W7-AS neutral beam heating systems. Ion sources of the first NBI system (NBI-1) for the KSTAR tokamak have been developed successfully with a bucket plasma generator based on the filament arc discharge, which have contributed to achieve a good plasma performance such as 15 sec H-mode operation with an injection of 3.5 MW NB power. There is a development plan of RF ion source at the KAERI to extract the positive ions, which can be used for the second NBI system (NBI-2) of the KSTAR and to extract the negative ions for future fusion devices such as Fusion Neutron Source and Korea-DEMO. The development progresses of RF ion source at the KAERI are described in this presentation.

• 한국수소및신에너지학회논문집
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• 제31권6호
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• pp.622-629
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• 2020

The performance and cost of electric vehicles (EVs) are much influenced by the performance and service life of the Li-ion battery system. In particular, the cell performance and reliability of Li-ion battery packs are highly dependent on their operating temperature. Therefore, a novel battery thermal management is crucial for Li-ion batteries owing to heat dissipation effects on their performance. Among various types of battery thermal management systems (BTMS'), the phase change material (PCM) based BTMS is considered to be a promising cooling system in terms of guaranteeing the performance and reliability of Li-ion batteries. This work is mainly concerned with the basic research on PCM based BTMS. In this paper, a basic experimental study on PCM based battery cooling system was performed. The main purpose of the present study is to present a comparison of two PCM-based cooling systems (n-Eicosane and n-Docosane) of the unit 18650 battery module. To this end, the simplified PCM-based Li-ion battery module with two 18650 batteries was designed and fabricated. The thermal behavior (such as temperature rise of the battery pack) with various discharge rates (c-rate) was mainly investigated and compared for two types of battery systems employing PCM-based cooling. It is considered that the results obtained from this study provide good fundamental data on screening the appropriate PCMs for future research on PCM based BTMS for EV applications.

• 한국수소및신에너지학회논문집
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• 제33권5호
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• pp.574-582
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• 2022

A lithium-ion battery exhibits high energy density but has many limitations due to safety issues. Currently, as a solution for this, research on solid state batteries is attracting attention and is actively being conducted. Among the solid electrolytes, sulfide-based solid electrolytes are receiving much attention with high ion conductivity, but there is a limit to commercialization due to the relatively high price of lithium sulfide, which is a precursor material. This study focused on the possibility of relatively inexpensive and light lithium hydride and conducted an experiment on it. In order to analyze the characteristics of LiAlH₄, ion conductivity and thermal stability were measured, and a composites mixed with PVDF, a representative polymer electrolyte, was synthesized to confirm a change in characteristics. And metallurgical changes in the material were performed through XRD, SEM, and BET analysis, and ion conductivity and thermal stability were measured by EIS and LFA methods. As a result, Li₃AlH₆ having ion conductivity higher than LiAlH₄ is formed by the synthesis of composite materials, and thus ion conductivity is slightly improved, but thermal stability is rapidly degraded due to structural irregularity.