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Bacillus sp. CS-17을 이용하여 제조한 청국장의 발효기간에 따른 향기성분 변호
최웅규,이석일,손동화,지원대 한국위생과학회 2002 한국위생과학회지 Vol.8 No.2
전통식으로 담근 청국장과 Bacillus sp. CS-17을 이용하여 제조한 청국장의 향기성분을 비교하였다. 전통식으로 제조한 청국장에서 동정된 향기성분은 hydrocarbone류가 5종, alcohol류가 5종, ester류가 4종, acid류가 3종, aldehyde류가 2종, ketone류가 2종, phenol류가 3종, furan류가 2종, pyrazine류가 4종 등 30종이 확인되었다. Bacillus sp. CS-17을 이용한 청국장에서 동정된 향기성분은 hydrocarbone류가 3종, alcohol류가 2종, aldehyde류가 2종, ketone류가 2종, phenol류가 3종, furan류가 3종, pyrazine류가 5종, pyridine류가 3종, 질소함유화합물로는 2종, thiazole류가 1종, 기타 화합물로 1종 등 모두 27종이 확인되었다. 동정된 성분 중에서 2-hydroxy-6-methylbenzaldehyde, 2-heptanone, 2-furancarboxaldehyde, 2.3-dimethyl-5-ethylpyrazine, 2-picoline, 3-picoline, 5-ethy1-2-picoline, trimethyloxazole, 1,2,6-trimethylpiperidine, 2,4,5-trimethylthiazole 및 chloroform 등의 성분들은 전통식으로 제조한 청국장에서는 확인이 되지 않았으나, Bacillus sp. CS-17을 이용한 청국장에서는 동정되었다. This study was conducted to compare flavor components of chunggugjang fermentated with Bacillus sp. CS-17 to those of traditional chunggugjang. 30 flavor components identified in traditional chunggugjang. 30 flavor components identified in traditional chunggugjang were five hydrocarbones, five alcohols, four esters, three acids, two aldehydes, two ketones, three phenols, two furans and four pyrazines. 27 flavor components identified chunggugjang fermentated with Bacillus sp. CS-17 were three hydrocarbones, two alcohols, two aldehydes, two ketones, three phenols, three furans, five pyrazines, three pyridines, two nitrogen containing compounds, one thiazole and one other compounds. Among the detected components, 2-hydroxy-6-methylbenzaldehyde, 2-heptanone, 2-furancarboxaldehyde, 2,3-dimethyl-5-ethylpyrazine, 2-picoline, 3-picoline, 5-ethy1-2-picoline, trimethyloxazole, 1,2,6-trimethylpiperidine, 2,4,5-trimethylthiazole and chloroform were identified in chunggugjang fermentared with Bacillus sp. CS-17, but not in traditional chunggugjang.
권오준,이은정,최웅규,손동화,이석일,정연건,지원대 한국위생과학회 2002 한국위생과학회지 Vol.8 No.2
새로운 장류제품으로서 보리등겨의 이용방안을 모색하기 위하여 간장을 만들어 연구하였다. 보리로 제조한 간장의 갈색화는 점차적으로 증가 하였으며 완만한 변화를 보였다. 향기성분으로는 4-vinyl-2-methoxy-phenol, benzeneacetaldehyde, palmitic acid, 2-furancatboxaldehyde, methyl-9, 12-octadecadienoate, di-(2-ethylhexyl)phthalate, diethyl phtalate, dibytyl-1,2-benzenedicatboxylate, 5-methyl-2-furancarboxaldehyde, 3,4-dimethyl-1h-pyrazole, phenylethyl alcohol, dioctyl-hexanedioate, dimethyl-1,2-benzenedicatboxylate, benzaldehyde, methional, 2-methoxy-phenol, n-furfurylidene-3-methylbutyl amine, 1-furfuryl-2-formyl pyrrole, tetradrcanoic acid, 5-methyl-pyrimidine, 4-methyl-5-hydroxymethyl-imidazole, maltol, 5-(5-methyl-2-furanyl)methyl-2-furancarboxaldehyde 순으로 높은 함량을 차지 하였다. For investigation of new utilization as jang-products, kanjang was prepared using barely bran. This study was conducted to investigate flavor components of kanjang during fermentation time. The optical density was gradually increased. Among the flavor components identified in kanjang made with barley bran, the contents of 4-viny1-2-methoxy-phenol was the most in quantity followed by benzeneacetaldehyde, palmitic acid, 2-furancarboxaldehyde, methyl-9,12-octadecadienoate, di-(2-ethylhexyl)phthalate, diethyl phtalate, dibutyl-1,2-benzendicarboxylate, 5-methyl-2-furancarboxaldehyde, 3,4-dimethyl-1h-pyrazole, phenylethyl alcohol, dioctyl-hexanedioate, dimethyl-1,2-benzenedicarboxylate, benzaldehyde, methional, 2-methoxy-phenol, n-furfurylidene-3-methylbutyl amine, 1-furfuryl-2-formyl pyrrole, tetradecanoic acid, 5-methyl-pyrimidine, 4-methyl-5-hydroxymethyl-imidazole, maltol and 5-(5-methyl-2-furanyl)methyl-2-furancarboxaldegyde.
Choi, Ji Ung,Kim, Jongsoon,Hwang, Jang-Yeon,Jo, Jae Hyeon,Sun, Yang-Kook,Myung, Seung-Taek unknown 2019 Nano energy Vol.61 No.-
<P><B>Abstract</B></P> <P>We propose P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB>, which is rationally designed as a promising cathode material for high-performance potassium-ion batteries (KIBs). Its composition adopts the use of the valence state of Mn above 3.5 + to minimize the disruptive effect of Jahn–Teller distortion in the MnO<SUB>6</SUB> octahedra during the electrochemical reaction. Unlike other types of layered materials that suffer from the sluggish diffusion of large potassium ions accompanying multi-step voltage profiles, P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB> delivers a high specific discharge capacity of 120.4 mAh (g-oxide)<SUP>−1</SUP> with smooth charge and discharge curves. First-principles calculations predict an activation barrier energy of ∼260 meV for a large K<SUP>+</SUP> diffusion, which is comparable to those observed in conventional layered cathode materials for lithium-ion batteries. As a result, even at 500 mA g<SUP>−1</SUP>, P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB> is able to deliver a high discharge capacity of 78 mAh g<SUP>−1</SUP>, which is a retention of 65% versus the capacity obtained at 20 mA g<SUP>−1</SUP>. Combination studies using <I>operando</I> X-ray diffraction, the <I>ex-situ</I> X-ray absorption near-edge structure, and first-principles calculations elucidate the nature of the excellent potassium storage mechanism of K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB>. This work provides a new insight for the development of efficient cathode materials for KIBs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB> is a new promising cathode for potassium-ion batteries. </LI> <LI> It has a high reversible capacity with excellent power capability in half cells. </LI> <LI> The low activation barrier energy promotes fast diffusion K<SUP>+</SUP> ions in the structure. </LI> <LI> It shows a single-phase reaction with reduced J-T distortion during cycles. </LI> <LI> It can be applicable to full cells with hard carbon anode having high reversible capacity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>We rationally design a new cathode material, P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB>, for potassium-ion batteries. The co-existence of Co<SUP>3+</SUP> and Mn<SUP>4+</SUP> in P3-K<SUB>0.54</SUB>[Co<SUB>0.5</SUB>Mn<SUB>0.5</SUB>]O<SUB>2</SUB> is highly effective at improving the structural stability by moderating the extent of the irreversible multiphase transformation, resulting in good cycling stability and rate capability.</P> <P>[DISPLAY OMISSION]</P>
Choi, Ji Ung,Park, Yun Ji,Jo, Jae Hyeon,Kuo, Liang-Yin,Kaghazchi, Payam,Myung, Seung-Taek American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.48
<P>Layered Na<SUB>2/3</SUB>MnO<SUB>2</SUB> suffers from capacity loss due to Jahn-Teller (J-T) distortion by Mn<SUP>3+</SUP> ions. Herein, density functional theory calculations suggest Na<SUB>2/3</SUB>[Fe<SUB><I>x</I></SUB>Mn<SUB>1-<I>x</I></SUB>]O<SUB>2</SUB> suppresses the J-T effect. The Fe substitution results in a decreased oxygen-metal-oxygen length, leading to decreases in the <I>b</I> and <I>c</I> lattice parameters but an increase in the <I>a</I> lattice constant. As a result, the capacity retention and rate capability are enhanced with an additional redox pair associated with Fe<SUP>4+/3+</SUP>. Finally, the thermal properties are improved, with the Fe substitution delaying the exothermic reaction and reducing exothermic heat.</P> [FIG OMISSION]</BR>
Impact of Na2MoO4 nanolayers autogenously formed on tunnel-type Na0.44MnO2
Choi, Ji Ung,Jo, Jae Hyeon,Jo, Chang-Heum,Cho, Min Kyoung,Park, Yun Ji,Jin, Yongcheng,Yashiro, Hitoshi,Myung, Seung-Taek The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.22
<P>We propose the coating of tunnel-type Na0.44MnO2 cathode materials with multi-functional Na2MoO4 nanolayers for use in rechargeable sodium batteries. Electro-conducting Na2MoO4 nanolayers (electrical conductivity of ∼10<SUP>3</SUP> S cm<SUP>−1</SUP>) are autogenously formed on the surface of Na0.44MnO2 particles through the reaction of (NH4)2MoO4 with surface sodium residues <I>via</I> melt impregnation at 350 °C. The Na2MoO4-modified Na0.44MnO2 electrode delivers discharge capacities of ∼120.4 mA h (g-oxide)<SUP>−1</SUP> at 0.1C (12 mA g<SUP>−1</SUP>) and 79.7 mA h g<SUP>−1</SUP> at 50C (6 A g<SUP>−1</SUP>). Moreover, with continuous cycling at a rate of 60C (7.2 A g<SUP>−1</SUP>), the Na2MoO4-coated Na0.44MnO2 electrode is able to retain a capacity of approximately 56 mA h g<SUP>−1</SUP> without notable capacity fading for 1000 cycles. This achievement is attributed to the presence of Na2MoO4 on the active materials, which facilitates electron transfer during electrochemical reaction in Na cells. More interestingly, Na2MnO4 undergoes two-step HF scavenging to finally form MoO3−xF2x layers <I>via</I> an intermediate of H2MoO4 (MoO3·H2O) layers. The surface layers protect the active materials from HF attack in the electrolyte. These multi-functional effects of the Na2MoO4 and MoO3−xF2x surface layers are responsible for the long-term cycle stability of the cathode material for ultra-high-rate sodium storage applications.</P>
Choi, Ji Ung,Yoon, Chong Seung,Zhang, Qian,Kaghazchi, Payam,Jung, Young Hwa,Lee, Kug-Seung,Ahn, Do-Cheon,Sun, Yang-Kook,Myung, Seung-Taek The Royal Society of Chemistry 2019 Journal of materials chemistry. A, Materials for e Vol.7 No.1
<P>We investigate the orthorhombic Na0.67[NixMn1−x]O2 (<I>x</I> = 0 and 0.05) cathode materials that provide high capacity for prolonged cycles. X-ray absorption studies revealed that the redox activity of the Mn<SUP>3+/4+</SUP> and Ni<SUP>2+/3+</SUP> pairs is effective in suppressing the Jahn-Teller effect of Mn<SUP>3+</SUP> ions because of the network with Ni<SUP>2+</SUP> ions. This effect influenced the smooth voltage variations in the voltage profile for Na0.67[Ni0.05Mn0.95]O2, whereas several complicated voltage plateaus associated with the first-order phase transition were noticed in Na0.67MnO2. <I>Operando</I> synchrotron X-ray diffraction and transmission microscopy studies confirmed the simplicity of the phase transition for Na0.67[Ni0.05Mn0.95]O2 due to suppression of the Jahn-Teller effect of Mn<SUP>3+</SUP> in the oxide lattice. These findings, along with the capacity retention during prolonged cycling and the acceptable thermal properties, make high-capacity sodium-ion batteries feasible, inexpensive, and safe for energy storage application.</P>