• Bulletin of the Korean Chemical Society
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• 제24권4호
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• pp.453-459
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• 2003

(Pyridine)(tetrahydroborato)zinc complex, $[Zn(BH_4)_2(py)]$, as a stable white solid, was prepared quantitatively by complexation of an equimolar amount of zinc tetrahydroborate and pyridine at room temperature. This reagent can easily reduce variety of carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and a, β-unsaturated carbonyl compounds to their corresponding alcohols in good to excellent yields. Reduction reactions were performed in ether or THF at room temperature or under reflux conditions. In addition, the chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing agent.

• 한국대기환경학회지
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• 제25권5호
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• pp.420-431
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• 2009

Characteristics and advantages of the thermal desorption-comprehensive two dimensional gas chromatography-time of flight mass spectrometry (TD-GCxGC-TOFMS) were discussed and the organic compound's analysis result was shown for the ambient $PM_{2.5}$ sample collected in Seoul, Korea. Over 10,000 individual organic compounds were separated from about $70{\mu}g$ of aerosols in a single procedure with no sample pre-treatment. Among them, around 300 compounds were identified and classified based on the mass fragmentation patterns and GCxGC retention times. Several aliphatic compounds groups such as alkanes, alkenes, cycloalkanes, alkanoic acids, and alkan-2-ones were identified as well as 72 PAH compounds including alkyl substituted compounds and 8 hopanes. In Seoul aerosol, numerous oxidized aromatic compounds including major components of secondary organic aerosols were observed. The inventory of organic compounds in $PM_{2.5}$ of Seoul, Korea suggested that organic aerosol were constituted by the compounds of primary source emission as well as the formation of secondary organic aerosols.

• 한국재료학회지
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• 제30권10호
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• pp.515-521
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• 2020

Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH₃NH₃PbBr₃, MAPbBr₃) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr₃ nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100 %) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr₃ nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.153-154
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• 2018

As the air pollution progresses, the pollution degree of the indoor air quality is increased, and when the pollution degree of the indoor air quality is increased, it causes respiratory diseases and skin diseases. In addition, volatile organic compounds are released from the materials used for architectural interior decoration, and volatile organic compounds are the main cause of polluting indoor air quality. In order to improve indoor air quality, we tried to secure indoor air quality pollution by using photocatalyst which has the function of decomposing harmful substances. photocatalyst is a material that promotes chemical reaction by absorbing light. The photocatalyst used in the experiment was TiO₂, In this study, an adsorption type hardener for reducing volatile organic compounds was prepared by photocatalytic reaction. the formaldehyde and CO₂ concentrations of the cured products were analyzed according to the TiO₂ content.

• 방사성폐기물학회지
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• 제20권2호
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• pp.193-207
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• 2022

Thermodynamically, TRUO_x, REO_x, and SrO_x can be chlorinated using ammonium chloride (NH₄Cl) as a chlorinating agent, whereas uranium oxides (U₃O₈ and UO₂) remain in the oxide form. In the preliminary experiments of this study, U₃O₈ and CeO₂ are reacted separately with NH₄Cl at 623 K in a sealed reactor. CeO₂ is highly reactive with NH₄Cl and becomes chlorinated into CeCl₃. The chlorination yield ranges from 96% to 100%. By contrast, U₃O₈ remains as UO₂ even after chlorination. We produced U/REO_x- and U/SrO_x-simulated fuels to understand the chlorination characteristics of the oxide compounds. Each simulated fuel is chlorinated with NH₄Cl, and the products are dissolved in LiCl-KCl salt to separate the oxide compounds from the chloride salt. The oxide compounds precipitate at the bottom. The precipitate and salt phases are sampled and analyzed via X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy, and inductively coupled plasma-optical emission spectroscopy. The analysis results indicate that REO_x and SrO_x can be easily chlorinated from the simulated fuels; however, only a few of U oxide phases is chlorinated, particularly from the U/SrO_x-simulated fuels.

• Journal of Magnetics
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• 제16권4호
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• pp.337-341
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• 2011

The magnetic and magnetocaloric properties of $Gd_{1-x}Ce_xAl_2$ (x = 0, 0.25, 0.5, 0.75) intermetallic compounds alloys have been investigated in detail for the first time. XRD patterns indicated that all the samples were crystallized in a single phase with $MgCu_2$-type structure (Laves phase). Ce substitution for Gd increased the lattice parameters and decreased the Curie temperature from 163 K for x = 0 to 37 K for x = 0.75. A maximum entropy change of 3.82 J/kg K was observed when a 2 T magnetic field was applied to the x = 0 sample. This entropy change decreased with increasing Ce content to 2.04 J/kg K for the x = 0.75 sample.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.60-64
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• 2003

The reactions of $[Pt(dppf)Cl_2]$ with thiophenol (PhSH), 1-propanethiol (n-PrSH), and 1,3-propanedithiol $(HSCH_2CH_2CH_2SH)$ gave the corresponding Pt-dppf-di(thiolato) compounds, $[Pt(dppf)(SPh)_2]\;(1),\;[Pt(dppf)(S-n-Pr)_2]\;(2),\;and [Pt(dppf)(SCH_2CH_2CH_2S)]\;(3)$, respectively. All products are monomeric and 4-coordinate square-planar compounds and were structurally characterized by X-ray diffraction. Electrochemical measurements (cyclovoltammograms) revealed that the oxidation potential of the dppf ligand appears to depend on the type of the group on the thiolato ligand.

• 한국자기학회지
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• 제23권6호
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• pp.179-183
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• 2013

최근에 발견된 $d^0$ 반쪽금속성을 가지는 호이슬러 화합물 $N_2KCa$와 $O_2KCa$이 합금을 이루었을 때 그 반쪽금속성과 자성을 제일원리 방법을 이용하여 연구하였다. 계산을 통해 얻은 상태밀도와 총 자기모멘트를 통해 고려의 대상인 $N_{1.5}O_{0.5}KCa$, NOKCa, $N_{0.5}O_{1.5}KCa$ 등 세 가지 화합물 모두 반쪽금속성 나타냄을 알 수 있었다. 이들 화합물에서 N 원자와 O 원자의 자기모멘트는 순수물질에 비해 상당히 증가하였으며, K 원자의 자기모멘트는 상당히 큰 음의 값을 가졌다. 각 원자들의 자기모멘트와 계산된 원자별 상태밀도를 연관시켜 자성과 반쪽금속성을 논의하였다.

• 한국재료학회지
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• 제25권2호
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• pp.68-74
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• 2015

The porous $Mg_3Sb_2$ based compounds with 60~70% of relative density were prepared by powder compaction at room temperature and reactive liquid phase sintering at 1023 K for 4hrs. The stoichiometric $Mg_3Sb_2$ compounds were synthesized from elemental Sb and Mg powder in the mixing range of 61~63 at% Mg. The increased scattering effect due to the micro-pores reduced the mobility of the charge carrier and the phonon, which caused the electrical conductivity and the thermal conductivity to decrease, respectively. But the scattering effect was greater for the electrical conductivity than for the thermal conductivity. Excess Mg alloyed in the $Mg_3Sb_2$ compounds decreased the electrical conductivity, but had no effect on the thermal conductivity. On the other hand, the large increase of the Seebeck coefficient was the result of a decrease in the charge carrier density due to the excess Mg. Dimensionless figure of merit of the porous $Mg_3Sb_2$ compound reached a maximum value of 0.28 at 61 at% Mg. The obtained value was similar to that of $Mg_3Sb_2$ compounds having little pores.

• The Korean Journal of Pain
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• 제33권3호
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• pp.216-225
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• 2020

Background: Garlic oil is a rich source of organosulfur compounds including diallyl disulfide and diallyl trisulfide. There have been studies showing the neuroprotective actions of these organosulfur compounds. However, the potential of these organosulfur compounds in neuropathic pain has not been explored. The present study was aimed at investigating the pain attenuating potential of diallyl disulfide and diallyl trisulfide in chronic constriction injury (CCI)-induced neuropathic pain in rats. The study also explored their pain-attenuating mechanisms through modulation of H₂S, brain-derived neurotrophin factor (BDNF) and nuclear factor erythroid 2-related factor 2 (Nrf2). Methods: The rats were subjected to CCI injury by ligating the sciatic nerve in four places. The development of neuropathic pain was measured by assessing mechanical hyperalgesia (Randall-Selittotest), mechanical allodynia (Von Frey test), and cold allodynia (acetone drop test) on 14th day after surgery. Results: Administration of diallyl disulfide (25 and 50 mg/kg) and diallyl trisulfide (20 and 40 mg/kg) for 14 days led to a significant reduction in pain in CCI-subjected rats. Moreover, treatment with these organosulfur compounds led to the restoration of H₂S, BDNF and Nrf2 levels in the sciatic nerve and dorsal root ganglia. Co-administration of ANA-12 (BDNF blocker) abolished pain attenuating actions as well as BDNF and the Nrf2 restorative actions of diallyl disulfide and diallyl trisulfide, without modulating H₂S levels. Conclusions: Diallyl disulfide and diallyl trisulfide have the potential to attenuate neuropathic pain in CCI-subjected rats possibly through activation of H₂S-BDNF-Nrf2 signaling pathway.