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Rapid Preparation of Monolithic Columns for Capillary Electrochromatography Separation

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Chinese Chemical Letters 2006年第6期17卷 813-816页

作者： Wen Jun GONG Yi Jun ZHANG Yu Ping ZHANG seong ho ChoI Henan Institute of Science and Technology Xinxiang 453003 Department of Chemistry Hannam University Daejon South Korea

Fritless packed silica gel columns were prepared using sol-gel technology, The part of a 75 μm i.d. capillary was filled with a mixture of methacryloxypropyltrimethoxysilane, toluene and hydrochloric acid. Four different photoinitiators such as benzoin methyl ether, Irgacure 819, Irgacure 1700 and Irgacure 1800 were added in the presence or absence of sodium dodecyl sulfate during the polymerization process. The above eight solutions were irradiated at 365 nm about 5-10 min to prepare the porous monolithic sol-gel columns by a one-step process.

关键词： Monolithic columns electrochromatography photopolymerized sol-gel.

A new strengthening mechanism driven by disruptive shear and solute segregation during warm rolling in 1.4 GPa class 12.5 wt% Al added-FeMnC ultra-lightweight steel

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Journal of Materials Science & Technology 2023年第26期157卷 174-188页

作者： Chiwon Kim Hyun-Uk hong Joonoh Moon Bong ho Lee seong-Jun Park Chang-hoon Lee Department of Materials Convergence and System Engineering Changwon National University 20 Changwondaehak-roChangwonGyeongnam 51140Republic of Korea Advanced Analysis Team Daegu Gyeongbuk Institute of Science and Technology 333 Technojungang-daeroDaegu42988Republic of Korea Ferrous Alloy Department Korea Institute of Materials Science 797 ChangwondaeroChangwonGyeongnam 51508Republic of Korea

Novel strengthening of Fe-29.1Mn-12.5Al-1.35C-4.95Cr steel achieved by warm rolling was *** solution-treated steel consisted of aγ-matrix containing nano-sizedκ-carbide((Fe,Mn)_(3) AlC)and elongated prior ferrite,which was transformed into FeAl-type B2 and Fe_(3) Al-type D0_(3) *** solution-treated steel exhibited poor strain hardening owing to glide softening associated withκ-carbide shearing by ***,after warm rolling with a reduction ratio of 30%at 300℃,the yield and tensile strengths significantly increased from 917 to 1300 MPa and 1025 to 1419 MPa,*** tensile test conducted at 300℃to simulate warm rolling exhibited serrated flows,indicating dy-namic strain aging(DSA).Atom probe tomography exhibited that the C atoms inκ-carbide were swept away along the slip direction by disruptive shear during rolling at 300℃.The swept C atoms along the slip direction interacted strongly with dislocations at 300℃,with repeated pinning and breakaway of dislocations from the C *** contributed to significant strengthening owing to the formation of a solute-rich atmosphere after warm *** results of the tensile tests at 300℃indicated that the de-gree of strengthening was proportional to the pre-strain *** strength of 1.4 GPa can be achieved with good ductility(17%elongation)by warm *** novel warm-rolling strengthening method ex-pedites the potential application of Fe-29.1Mn-12.5Al-1.35C-4.95Cr as a 1.4 GPa class ultra-lightweight steel.

关键词： FeMnAlC Cr addition κ-carbide Dynamic strain aging Strengthening

Hydrogels for active photonics

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Microsystems & Nanoengineering 2024年第1期10卷 1-16页

作者： Byoungsu Ko Nara Jeon Jaekyung Kim Hyunjung kang Junhwa seong Suhyeon Yun Trevon Badloe Junsuk Rho Department of Mechanical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Department of Chemical Engineering Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea Graduate School of Artificial Intelligence Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics Pohang 37673Republic of Korea

Conventional photonic devices exhibit static optical properties that are design-dependent,including the material’s refractive index and geometrical ***,they still possess attractive optical responses for applications and are already exploited in devices across various *** photonics has emerged as a promising solution in the field of active photonics by providing primarily deformable geometric parameters in response to external *** the past few years,various studies have been undertaken to attain stimuli-responsive photonic devices with tunable optical ***,we focus on the recent advancements in hydrogel-based photonics and micro/nanofabrication techniques for *** particular,fabrication techniques for hydrogel photonic devices are categorized into film growth,photolithography(PL),electron-beam lithography(EBL),and nanoimprint lithography(NIL).Furthermore,we provide insights into future directions and prospects for deformable hydrogel photonics,along with their potential practical applications.

关键词： lithography photonics attractive

Surface plasmon enhancement of photoluminescence in photo-chemically synthesized graphene quantum dot and Au nanosphere

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Nano Research 2016年第6期9卷 1866-1875页

作者： Byeongho Park Sun Jun Kim Ji Soo Sohn Min Sik Nam Shinill kang seong Chan Jun School of Mechanical Engineering Yonsei University 50 Yonsei-ro Seodaemun-gu Seou1120-749 Republic of Korea

Graphene quantum dots （GQDs） are promising candidates for potential applications such as novel optoelectronic devices and bio-imaging. however, insufficient light absorption to exhibit their intriguing characteristics. The strong confinement of light caused by the Au nanoparticles as an antenna can considerably boost the light absorption. With the assistance of ultraviolet irradiation, we prepared bluish-green luminescent nanospheres by the hybridiza- tion of GQD and Au nanoparticles （GQD/Au）. These nanospheres showed a photoluminescence quantum yield of up to 26.9%. The GQD/Au nanospheres were synthesized using a solution of GQDs and HAuC14 by a photochemical method with the reduction of GQDs and the formation of metallic Au. The GQDs and Au nanopartides self-assembled and aggregated into nanospheres via aurophilicity and hydrogen bonding interactions. The average size of the GQD/Au nanospheres was found to be in the range of 150-170 nm, which is much larger than that of the pristine GQDs （4-7 nm）. The GQD/Au nanospheres exhibited an absorption band at 541 nm, which indicates the presence of Au in the nanospheres. The typical absorbance features of GQDs were observed near 236 and 303 nrn. The photoluminescence characteristics were investigated using the excitation and emission spectra. The GQD/Au nanospheres exhibited two emission peaks at 468 and 529 nm in the visible range. The green fluorescent peak located at 529 nm was newly generated by the hybridization. The GQD/Au nanospheres showed an emission efficiency which was two times more than that of the intrinsic GQDs. The reason for this increase was the surface plasmon resonance from the Au particles, which improved the fluorescence property of the resulting nanospheres. These nanospheres can be perceived as outstanding candidates for applications such as displays, optoelectronic devices, and imaging of the biological samples with high emission intensity.

关键词： graphene quantum dot gold nanosphere photoluminescence UV irradiation

Numerical simulation for dendrite growth in directional solidification using LBM-CA(cellular automata)coupled method

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Journal of Materials Science & Technology 2020年第14期47卷 15-24页

作者： Wonjoo Lee Yuhyeong Jeong Jae-Wook Lee howon Lee seong-hoon kang Young-Min Kim Jonghun Yoon Department of Mechanical Design Engineering Hanyang University222Wangsimni-roSeongdong-guSeoul 04763Republic of Korea Materials Deformation Department Korea Institute of Materials Science797 ChangwondaeroSeongsan-guChangwon-siGyeongnam-do 51508Republic of Korea Department of Mechanical Engineering Hanyang University55 Hanyangdaehak-roSangnok-guAnsan-siGyeonggi-do 15588Republic of Korea

To predict the dendrite morphology and microstructure evolution in the solidification of molten metal,numerically,lattice Boltzmann method(LBM)-cellular automata(CA)model has been developed by integrating the LBM to solve the mass transport by diffusion and convection during solidification and the CA to determine the phase transformation with respect to the solid fraction based on the local equilibrium *** is successfully validated with analytic solutions such as Lipton-Glicksman-Kurz(LGK)model in static melt,and Oseen-Ivantsov solution under the fluid flow conditions in terms of tip radius and velocity of the dendrite *** proposed LBM-CA model does not only describe different types of dendrite formations with respect to various solidification conditions such as temperature gradient and growth rate,but also predict the primary dendrite arm spacing(PDAS)and the secondary dendrite arm spacing(SDAS),quantitatively,in directional solidification(DS)experiment with Ni-based superalloy.

关键词： Cellular automata(CA) Lattice Boltzmann method(LBM) Dendritic growth Directional solidification

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枳椇子中甾类化合物的分离

中药材 2006年第1期29卷 21-23页

作者：张晶陈全成 Young ho Kim Jong seong kang 吉林农业大学中药材学院吉林长春130118 韩国忠南大学药学院

从枳椇子hovenia acerba中分离得到3个化合物,分别为β-谷甾醇(-βsitosterol)(Ⅰ);3β-Hydroxy-3-de-oxymoron ic ac id(Ⅱ)和胡萝卜苷(Ⅲ)。上述三个化合物均为自该属植物中首次获得。

关键词：枳棋子 3β-Hydroxy-3-deoxymoronic acid

Predicting tumor response after preoperative chemoradiation using clinical parameters in rectal cancer

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World Journal of Gastroenterology 2011年第48期17卷 5310-5316页

作者： Chan ho Park Hee Cheol Kim Yong Beom Cho seong Hyeon Yun Woo Yong Lee Young Suk Park Doo ho Choi ho-Kyung Chun Departmentof Surgery Samsung Medical Center Sungkyunkwan Univer-sity School of Medicine Irwon-dong 50 Gangnam-gu Seoul135-710 South Korea Division of Hematology-Oncology Depart-ment of Medicine Samsung Medical Center Sungkyunkwan University School of Medicine Irwon-dong 50 Gangnam-guSeoul 135-710 South Korea Department of Radiation Oncology SamsungMedical Center Sungkyunkwan University School of MedicineIrwon-dong 50 Gangnam-gu Seoul 135-710 South Korea

AIM: To evaluate the clinical parameters and identify a better method of predicting pathological complete response (pCR). METhoDS: We enrolled 249 patients from a database of 544 consecutive rectal cancer patients who underwent surgical resection after preoperative chemoradiation therapy (PCRT). A retrospective review of morphological characteristics was then performed to collect data regarding rectal examination findings. A scoring model to predict pCR was then created. To validate the ability of the scoring model to predict complete ***: Seventy patients (12.9%) achieved a pCR. A multivariate analysis found that pre-CRT movability (P = 0.024), post-CRT size (P = 0.018), post-CRT morphology (P = 0.023), and gross change (P = 0.009) were independent predictors of pCR. The accuracy of the scoring model was 76.8% for predicting pCR with the threshold set at 4.5. In the validation set, the accuracy was 86.7%. CONCLUSION: Gross changes and morphological findings are important predictors of pathological response. Accordingly, PCRT response is best predicted by a combination of clinical, laboratory and metabolic information.

关键词： Rectal cancer Preoperative chemoradiotherapy Downstaging Tumor regression Validation

Optical diffraction gratings embedded in BK-7 glass by low-density plasma formation using femtosecond laser

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 165-169页

作者： Jung-Kyu PARK Sung-Hak Cho Kwang-ho KIM Myung-Chang kang Nano Machining Laboratory Korea Institute of Machinery and Material Daejeon 305-343 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

The optical embedded diffraction gratings with the internal refractive index modification in BK-7 glass plates were demonstrated using low-density plasma formation excited by a high-intensity femtosecond （130 fs） Ti： sapphire laser （λp=790 rim）. The refractive index modifications with diameters ranging from 400 nm to 4 gm were photoinduced after plasma formation occurred upon irradiation with peak intensities of more than 1 ×10^13 W/cm2. The graded refractive index profile was fabricated to be a symmetric around the center of the point at which low-density plasma occurred. The maximum refractive index change （An） was estimated to be 1.5x10 2. Several optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

关键词： BK-7 glass plate diffraction grating refractive index modification plasma formation femtosecond laser

High-concentration dispersions of exfoliated MoS2 sheets stabilized by freeze-dried silk fibroin powder

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Nano Research 2016年第6期9卷 1709-1722页

作者： HeungBo Sim JiYong Lee Byeongho Park Sun Jun Kirn Shinill kang ,WonHyoung Ryu seong Chan Jun School of Mechanical Engineering Yonsei University Seoul 120-749 Republic of Korea

Liquid-phase exfoliation （LPE） is an attractive method for the scaling-up of exfoliated MoS2 sheets compared to chemical vapor deposition and mechanical cleavage. however, the MoS2 nanosheet yield from LPE is too small for practical applications. We report a facile method for the scaling-up of exfoliated MoS2 nanosheets using freeze-dried silk fibroin powders. Compared to MoS2 dispersion in the absence of silk fibroin powder, sonicated MoS2 dispersions with silk fibroin powder （MoSJSilk dispersion） show noticeably higher exfoliated MoS2 nanosheet yields, with suspended MoS2 concentrations in MoS2/Silk dispersions sonicated for 2 and 5 h of 1.03 and 1.39 ***-1, respectively. The MoS2 concentration in the MoS2/Silk dispersion after centrifugation above 10,000 rpm is more than four times that without the silk fibroin. The size of the dispersed silk fibroin is controlled by the change of centrifugation rate, showing the removal of silk fibroin above tens of micrometers in size after centrifugation at 2,000 rpm. Size-controlled silk fibroin biomolecules combined with MoS2 nanosheets are expected to increase the practical use of such materials in fields related to tissue engineering, biosensors and electrochemical electrodes. Atomic force microscopy and Raman spectroscopy provide the height of the MoS2 nanosheets spin-cast from MoS2/Silk dispersions, showing thicknesses of 3--6 nm. X-ray photoelectron spectroscopy and X-ray diffraction indicate that the outermost surface layer of the hydrophobic MoS2 crystals interact with oxygen-containing functional groups that exist in the hydrophobic part of silk fibroins. The amphiphilic properties of silk fibroin combined with the MoS2 nanosheets stabilize dispersions by enhancing solvent-material interactions. The large quantities of exfoliated MoS2 nanosheets suspended in the as-synthesized dispersions can be utilized for the fabrication of vapor and electrochemical devices requiring high MoS2 nanosheets contents.

关键词： MoS2 nanosheet liquid-phase exfoliation freeze-dried silk fibroin powder amount of suspended MoB2 sheet stabilized dispersion