• Archives of Pharmacal Research
• /
• v.15 no.1
• /
• pp.73-77
• /
• 1992

From the roots of Angelica dahurica Bentham et Hooker (Umbelliferae), five coumarin glucosides together with adenosine have been isolated and identified as nodakenin, 3'-hydroxymarmesinin, tert-O-$\beta$-D-glucopyranosyl-byakangelicin, sec-O-$\beta$-D-glucopyranosyl-byakangelicin and scopolin. This is the first report of the occurrence of these compounds in this plant.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.403-406
• /
• 2004

In this paper, the design of damped structures associated with the piezoelectric shunt circuits is undertaken and it is applied to optical disk drive (O.D.D) main base in order to reduce unwanted vibration. In order to design effective piezoelectric structure, the admittance of the structure is introduced as the performance index of the piezoelectric shunt system. And the admittance offset of the shunt performance is theoretically investigated. It is also presented that the admittance can be calculated by commercial finite elements program. To verify the admittance calculated by F.E.M, admittance measurement is performed by impedance analyzer. In this verifying process, the validity of the finite element admittance analysis is found. As a practical approach, to reduce the vibration of the O.D.D. main base, piezoelectric shunt system is designed using the proposed admittance analysis and shunt effect is evaluated at all prescribed frequencies.

• Journal of the Korean Chemical Society
• /
• v.42 no.1
• /
• pp.78-83
• /
• 1998

It's necessary to develope a facile methodology forming ${\alpha}$-altropyranosidic linkage, for the synthesis of trisaccharide repeating unit of O-antigenic part of Campylobacter jejuni gram negative bacteria. In this paper, the effective synthesis of disaccharides containing ${\alpha}$-altropyranosidic linkage by 1,2-trans glycosidation of allal derivatives was discussed. 4, 6-O-Benzylidene-3-O-(t-butyldimethylsilyl)-D-allal was treated with DMDO (3,3-dimethy ldioxirane) to yield 1,2-anhydro-4, 6-O-benzylidene-3-O-(t-butyldimethylsilyl)-${\beta}$-D-altropyranose. The reaction of 1,2-anhydro-4, 6-O-benzylidene-3-O-(t-butyldimethylsilyl)-${\beta}$-D-altropyranose with allyl alcohol gave allyl 4, 6-O-benzylidene-3-(t-butyldimethylsilyl)-${\alpha}$-D-altropyranoside quantitatively, and reactions with glucals were also successful to prepare ${\alpha}$-altropyranosodic disaccharides. It is convinced that 1,2-trans glycosidation of allal derivatives should be an attractive choice for preparing oligosaccharides containing ${\alpha}$-altropyranosidic linkages.

• Journal of Powder Materials
• /
• v.27 no.5
• /
• pp.381-387
• /
• 2020

In this work, TiO₂ 3D nanostructures (TF30) were prepared via a facile wet chemical process using ammonium hexafluorotitanate. The synthesized 3D TiO₂ nanostructures exhibited well-defined crystalline and hierarchical structures assembled from TiO₂ nanorods with different thicknesses and diameters, which comprised numerous small beads. Moreover, the maximum specific surface area of TiO₂ 3D nanostructures was observed to be 191 ㎡g^-1, with concentration of F ions on the surface being 2 at%. The TiO₂ 3D nanostructures were tested as photocatalysts under UV irradiation using Rhodamine B solution in order to determine their photocatalytic performance. The TiO₂ 3D nanostructures showed a higher photocatalytic activity than that of the other TiO₂ samples, which was likely associated with the combined effects of a high crystallinity, unique features of the hierarchical structure, a high specific surface area, and the advantage of adsorbing F ions.

• Journal of the Mineralogical Society of Korea
• /
• v.16 no.1
• /
• pp.65-73
• /
• 2003

In this study we have derived the two correction methods of hydrogen bonding distance. In case of the intermediate or long hydrogen bond(＞2.5 $\AA$), hydrogen bonding distances can be corrected by using the function d(O-H)=exp((2.173-d(O…O))/0.138)+0.958 obtained by least- squares fit to the data from the neutron diffraction at low temperatures. The valence-least-squares method is effective for the distance correction of very short hydrogen bond(<2.5 $\AA$). The distance correction is necessary for the long intermolecular hydrogen bond obtained from X-ray diffraction analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1992.11a
• /
• pp.136-140
• /
• 1992

The purpose of this research is to develop the lithium secondary battery. This paper describes the preparation, electrochemical properties of nontstoichiometric(NS)-$V_6O_{13}$ and characteristics of Li/$V_6O_{13}$ secondary battery. NS-$V_6O_{13}$ was prepared by thermal decomposition of $NH_4VO_3$ under Ar stream of 140ml/min~180ml/min flow rate. And then, this NS-$V_6O_{13}$ was used for cathode active material. Cathode sheet was prepared by compressing the composite of NS-$V_6O_{13}$, acetylene black(A.B) and teflon emulsion (T.E). Characteristics of the test cell are summarised as follows. Oxidation capacity of NS-$V_6O_{13}$ was about 20% less than its reduction capacity. A part of NS-$V_6O_{13}$ cathode active material showed irreversible reaction in early charge-discharge cycle. This phenomena seems to be caused by irreversible incoporation/discoporation of lithium cation to/from NS-$V_6O_{13}$ host. Discharge characteristics curve of Li/$V_6O_{13}$ cell showed 4 potential plateaus. Charge-discharge capacity was declined in the beginning of cycling and slowly increased in company with increasing of coulombic efficiency. Energy density per weight of $V_6O_{13}$ cathode material was as high as 522Wh/kg~765Wh/kg.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.2
• /
• pp.113-118
• /
• 2016

This experiment was conducted to identify the variations in inorganic nutrients and plant growth in millet (Panicum miliaceum L.) due to soil salinity. The soil series was Munpo and soil texture was silt loam. The experimental soil was amended so that the soil had salinities of $0.8dS\;m^{-1}$, $1.6dS\;m^{-1}$, $3.2dS\;m^{-1}$ and $4.8dS\;m^{-1}$. Millet was transplanted 15 days after sowing. As soil salinity increased, the degree of reduced growth was in the order of seed production > root dry matter > plant dry matter > culm length > tiller number > stem thickness > Panicle length. Seed production was decreased to 18.9% in soil salinity of $1.6dS\;m^{-1}$, 36.9% in of $3.2dS\;m^{-1}$, and 50.7% in EC of $4.8dS\;m^{-1}$. Root dry matter decreased to 35.8% in EC of $3.2dS\;m^{-1}$, and to 40.5% in EC of $4.8dS\;m^{-1}$. As soil salinity increased, Total nitrogen content increased in all aboveground parts, roots and seeds. However, There was no difference in CaO, $P_2O_5$, $K_2O$ and, MgO in soils of different salinity. On the other hand, $Na_2O$ content was higher in the order roots> shoots> seed, and in the case of roots, $Na_2O$ content increased to 1.02% in soil salinity of $4.8dS\;m^{-1}$. However, up to soil salinity of $1.6dS\;m^{-1}$, the $Na_2O$ content of the seed was similar to that in plant grown in the Control conditions($0.8dS\;m^{-1}$). In conclusion, taking into consideration economic factors, millet could be cultivated in soil with salinities of up to approximately $1.6dS\;m^{-1}$, and seed produced from reclaimedland would be suitable for human consumption.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.28 no.2
• /
• pp.99-103
• /
• 2015

One-dimensional photonic crystals (1D PCs) were fabricated by RF sputtering technique on p-Si (100), and fused quartz substrates. The 1D PCs structures consisted of $TeO_x$ (x=1.42), and $SiO_2$ with the difference refractive index. In order to estimate the effect on a defect level within 1D PCs structures, samples were prepared with both normal, and defect mode. The structural and optical properties were confirmed by Scanning electron microscope (SEM), and Ultraviolet visible near-infrared spectrophotometer (UV-VIS-NIR) respectively. In the case of a 1D PC normal mode without defect layer, it had a photonic band gap (PBG) in the near infrared (NIR) region. In the case of a 1D PC defect mode with defect layer, it had a sharp transmission band owing to a defect level, and moved towards the longer wavelength after exposing He-Cd laser with a wavelength of 325 nm.

• Korean Journal of Mineralogy and Petrology
• /
• v.34 no.3
• /
• pp.177-191
• /
• 2021

The Zhenzigou Pb-Zn deposit, one of the largest Pb-Zn deposit in the northeast of China, is located at the Qingchengzi mineral field in Jiao Liao Ji belt. The geology of this deposit consists of Archean granulite, Paleoproterozoinc migmatitic granite, Paleo-Mesoproterozoic sodic granite, Paleoproterozoic Liaohe group, Mesozoic diorite and monzoritic granite. The Zhenzigou deposit which is a strata bound SEDEX or SEDEX type deposit occurs as layer ore and vein ore in Langzishan formation and Dashiqiao formation of the Paleoproterozoic Liaohe group. Based on mineral petrography and paragenesis, dolomites from this deposit are classified three type (1. dolomite (D₀) as hostrock, 2. dolomite (D₁) in layer ore associated with white mica, quartz, K-feldspar, sphalerite, galena, pyrite, arsenopyrite from greenschist facies, 3. dolomite (D₂) in vein ore associated with quartz, apatite and pyrite from quartz vein). The structural formulars of dolomites are determined to be Ca_1.00-1.03Mg_0.94-0.98Fe_0.00-0.06As_0.00-0.01(CO₃)₂(D₀), Ca_0.97-1.16Mg_0.32-0.83Fe_0.10-0.50Mn_0.01-0.12Zn_0.00-0.01Pb_0.00-0.03As_0.00-0.01(CO₃)₂(D₁), Ca_1.00-1.01Mg_0.85-0.92Fe_0.06-0.11 Mn_0.01-0.03As_0.01(CO₃)₂(D₂), respectively. It means that dolomites from the Zhenzigou deposit have higher content of trace elements compared to the theoretical composition of dolomite. Feo and MnO contents of these dolomites (D₀, D₁ and D₂) contain 0.05-2.06 wt.%, 0.00-0.08 wt.% (D₀), 3.53-17.22 wt.%, 0.49-3.71 wt.% (D₁) and 2.32-3.91 wt.%, 0.43-0.95 wt.% (D₂), respectively. The dolomite (D₁) from layer ore has higher content of these trace elements (FeO, MnO, ZnO and PbO) than dolomite (D₀) from hostrock and dolomite (D₂) from quartz vein. Dolomites correspond to Ferroan dolomite (D₀ and D₂), and ankerite and Ferroan dolomite (D₁), respectively. Therefore, 1) dolomite (D₀) from hostrock is a Ferroan dolomite formed by marine evaporative lagoon environment in Paleoproterozoic Jiao Liao Ji basin. 2) Dolomite (D₁) from layer ore is a ankerite and Ferroan dolomite formed by hydrothermal metasomatism origined metamorphism (greenschist facies) associated with Paleoproterozoic intrusion. 3) Dolomte (D₂) from quartz vein is a Ferroan dolomite formed by hydrothermal fluid origined Mesozoic intrusion.

• Journal of the Korean Vacuum Society
• /
• v.4 no.4
• /
• pp.413-416
• /
• 1995

고주파 마그네트론 스펏터링법을 이용하여 ZnO막을 제조하고 유리기판 위에 ZnO-SAW필터를 제작하였다. ZnO막의 제조 조건은 고주파 전력 150W, 기판온도 $200^{\circ}C$, 분위기압 5mTorr 및 O2/(Ar+O2)비 50%였다. 한편 IDT(Inter-digital transducer)전극은 전극 폭을 2.56mm, 전극 거리를 2,936mm, λ/8폭을 $8mu$m로 설계하였다. 제작된 ZnO-SAW필터의 주파수 응답을 측정하기 위해 소자는 mount(TO8)에 고정시켰다. ZnO SAW필터의 통과 대역(3 dB대역폭)은 345.2~44.8 MHz로 9.6MHz의 대역 폭을 나타내었으며 중심주 파수는 40 MHz를 나타내었다. 또한 삽입 손실은 39 dB, 통과 대역에서의 리플(ripple)은 $\pm$ 0.8 dB 및 rejection은 17 dB를 나타내었다.