• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.248-248
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• 2009

Recently, the control of size, morphology and dimensionality in inorganic materials has been rapidly developed into a promising field in materials chemistry. 3D nanostructured flower-like ZnO architecture with different size and shapes have been simply synthesized via a hydrothermal process, using zinc acetate and ammonium hydroxide as reactants.[1] In this study, the Zno thin-films were deposited by RF magnetron sputtering in other to get high adhesion and uniformity of 3D nanostructured flower-like ZnO architecture on a $SiO_2$ substrate. The XRD patterns identified that the obtained the nanocrystallized ZnO architecture exhibited a wurtzite structure. SEM images illustrated that the flower-like ZnO bundles consisted of flower-like or chestnut bur, which were characterized by polycrystalline and [0001] preferential orientation.

• 한국전기전자재료학회논문지
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• 제22권10호
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• pp.884-889
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• 2009

Recently, the control of size, morphology and dimensionality in inorganic materials has been rapidly developed into a promising field in materials chemistry. 3D nanostructured flower-like ZnO architecture with different size and shapes have been simply synthesized by hydrothermal process, using zinc acetate and ammonium hydroxide as reactants. In this study, the ZnO thin-films were deposited by RF magnetron sputtering in other to get high adhesion and uniformity of 3D nanostructured flower-like ZnO architecture on a $SiO_2$ substrate. The XRD patterns identified that the obtained the nanocrystallized ZnO architecture exhibited a wurtzite structure. SEM images illustrated that the flower-like ZnO bundles consisted of flower-like or chestnut bur, which were characterized by polycrystalline and (002) preferential orientation.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.285-295
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• 2021

The inverse spinel Cobalt ferrite (CoFe₂O₄, CFO) is considered to be a promising alternative to commercial graphite anodes for lithium ion batteries (LIBs). However, the further development of CFO is limited by its unstable structure during battery cycling and low electrical conductivity. In an effort to address the challenge, we construct three-dimensional hierarchical flower-like CFO nanoclusters (CFO NCs)-decorated carbonized cotton carbon fiber (CFO NCs/CCF) composite. This structure is consisted of microfibers and nanoflower cluster composited of CFO nanoparticle, in which CCF can be used as a long-range conductive matrix, while flower-like CFO NCs can provide abundant active sites, large electrode/electrolyte interface, short lithium ion diffusion path, and alleviated structural stress. As anode materials in LIBs, the flower-like CFO NCs/CCF exhibits excellent electrochemical performance. After 100 cycles at a current density of 0.3 A g^-1, the CFO NCs/CCF delivers a discharge/charge capacity of 1008/990 mAh g^-1. Even at a high current density of 15 A g^-1, it still maintains a charge/discharge capacity of 362/361 mAh g^-1.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.314-319
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• 2016

플랜지 볼트는 체결하중을 분산시키기 위한 와셔와 같은 역할을 하는 플랜지를 가지고 있으며, 주로 냉간단조로 성형된다. 플랜지의 단조 시 꽃무늬 모양의 결함이 발생할 수 있다. 이 결함은 치수 정밀도 및 품질 저하 등의 문제점을 야기할 수 있어 이에 대한 개선이 요구된다. 본 논문에서는 플랜지 볼트의 플라워 형상 결함을 개선하기 위한 금형 설계방법을 제안하고자 하였다. 이를 위해 기존의 단조 공정에서 앞판의 내경을 변수로 금형을 수정하였다. 수정된 금형을 적용한 단조 공정은 상용 유한요소해석 코드인 DEFORM-3D를 이용하여 시뮬레이션 하였고, 해석결과를 기준으로 단조 실험을 하여 결과의 신뢰성을 검증하였다.

• 센서학회지
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• 제19권5호
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• pp.356-360
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• 2010

Due to the high surface-to-volume ratio, the 3-dimensional(3D) nanostructures of metal oxides are regarded as the best candidate materials for the chemical gas sensors. Here we have synthesised flower-like 3D zinc oxide nanostructures through a simple hydrothermal route. Specific surface area of the 3D zinc oxide nanostructures synthesised in different pH values from 9.0 to 12.0 were evaluated by using a BET analyzer and the results were compared with that of a zinc oxide thin film fabricated by rf sputtering. Using interdigitated electrodes, superior CO gas sensing properties of the 3D zinc oxide nanostructures on the ZnO thin film to those of the ZnO thin film were demonstrated.

• 기술사
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• 제38권3호
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• pp.6-12
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• 2005

DMB(Digital Multimedia Broadcasting) Service was started, DMB enables people on the move to enjoy seamless video streaming, theater-quality audio and data through a hand-held digital device much like a handset or an in-car terminal. Realization of any-time, any-where, any-device, any-one DMB Service is needed for the government effective policy, Technical R&D and Standization, Corporate investment.

• 식물분류학회지
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• 제52권3호
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• pp.144-155
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• 2022

Daphne kiusiana is an evergreen shrub with dense head-like umbels of white flowers distributed in southern Korea, Japan, China, and Taiwan. Plants in China and Taiwan are recognized as var. atrocaulis by having a dark purple stem, elliptic leaves, and persistent bracts. Recently, plants on Jejudo Island were segregated as a separate species, D. jejudoensis, given their elliptic leaves with an acuminate apex, a long hypanthium and sepals, and a glabrous hypanthium. Morphological variations of three closely related taxa, the D. kiusiana complex, were investigated across the distributional range to clarify the taxonomic delimitation of members of the complex. Twelve characters of the leaf and flower were measured from digitized herbarium specimens using the image analysis program ImageJ and were included in a morphometric analysis, the results of which indicate that the level of variation in the characters is very high. The results of a principal component analysis weakly separated D. jejudoensis from D. kiusiana according to their floral characteristics, such as a longer, glabrous hypanthium, and larger sepals. However, some individuals of D. kiusiana, particularly those from Bigeumdo Island, were included in D. jejudoensis. Recognition of D. kiusiana var. atrocaulis based on the leaf shape was not supported in the analysis, and D. jejudoensis may be recognized as a variety of D. kiusiana. Our morphometric analysis shows that digitized images of herbarium specimens could be useful and an additional method by which to investigate more diverse specimens.

• Mass Spectrometry Letters
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• 제14권2호
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• pp.25-35
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• 2023

Plants are a traditional source of many chemicals used as biochemical, flavors, food, color, and pharmaceuticals in various countries, especially India. Most herbal medicines and their derivatives are often made from crude extracts containing a complex mixture of various phytochemical chemical components (secondary metabolites of the plants). This study aimed to identify bioactive compounds from the different parts of the plant from the ethanolic extract of Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis (leaves, flower, stem) by gas chromatography-mass spectroscopy (GC-MS). The gas chromatography - mass spectrometry analysis revealed the presence of various compounds like 3,4-dimethylcyclohexanol, hexanoic acid, D-mannose, and N-decanoic acid. Hence, the Gymnema sylvestre, Senna auriculata, and Cissus quadrangularis may have chemopreventive, anti-cancer, anti-microbial activity, antioxidant, anti-diabetic activity, anti-inflammatory, and antifungal due to the presence of secondary metabolites in the ethanolic extract. These phytochemicals are supported for traditional use in a variety of diseases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.171.2-171.2
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• 2015

Nowadays, trivalent rare-earth ($RE^{3+}$) ions activated metal oxides have been proved to be excellent host materials due to their various applications. Facile wet-chemical technique have been considered as the best synthetic route due its intensive interest in the preparation of nanostructures. Europium ion doped lanthanum hydroxide ($La(OH)_3:Eu^{3+}$) phosphors were synthesized by the facile wet chemical method using the hexamethylenetetramine (HMTA) as a mediated surfactant. The thermal behavior for the $La(OH)_3:Eu^{3+}$ phosphors was investigated by thermogravimetric and differential thermal analysis method. The morphological studies were measured by scanning electron microscope and transmission electron microscope measurements, indicating three-dimensional (3D) flower-like $La(OH)_3:Eu^{3+}$ nanorod bundles. After subsequent annealing process, the lanthanum oxide ($La_2O_3:Eu^{3+}$) phosphor exhibited similar kind of morphology. The synthesized $La(OH)_3:Eu^{3+}$ and $La_2O_3:Eu^{3+}$ samples were characterized by X-ray powder diffraction and Fourier transform infrared spectroscopy. Furthermore, photoluminescence and cathodoluminescence properties were studied in details.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2022년도 추계학술대회
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• pp.73-73
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• 2022

Lettuce (Lactuca sativa L., Family Asteraceae) is highly ranked in production and economic value and is consumed either fresh or in salad mixes because of its important dietary source of bioactive phytochemicals. The world collection of Lactuca spp. leafy crops, maintained in NAC, includes 2,464 accessions from 71 countries around the world, of which 2,411 belong to L. sativa species, nineteen to L. saligna, and fifteen to L. serriolar. We aimed to investigate the lettuce germplasm with morphological and biochemical analyses and provide new material for breeding. The lettuce crop comprises seven main groups of cultivars (including oilseed lettuce) differing phenotypically. Agricultural characteristcs were investigated including time to bolting, time to flowering, seed color, flower color, leaf attitude, leaf color, leaf anthocyanin coloration, type of incision of margin, depth of incisions of margins, and leaf venation. Screening of the health beneficial metabolites like anthocyanin and bitter sesquiterpene lactones (lactucin and lactucopicrin) was also conducted. The range of anthocyanin and SLs were 0~563.78 mg/100g D.W. and 3.74~3311.66 ug/g D.W., respectively. The investigation of the degree of variation regarding phenotypic traits and biochemical revealed adaptive stable and highly variable use of trait collection.