Synthesis and Characterization of Co-Surfactant Templated Mesoporous Materials with Enhanced Hydrothermal Stability

Kim Geon-Joong,Kim Hyun-Seok,Ko Yoon Soo,Kwon Yong Ku The Polymer Society of Korea 2005 Macromolecular Research Vol.13 No.6

Ordered mesoporous materials with a hydrothermally-stable, protozeolitic framework were prepared by exploring the direct conversion of inorganic species based on co-surfactant templating systems. To confer hydrothermal stability on the mesoporous aterials, the organic-inorganic hybrids were heat-treated in strongly basic media. Co-surfactant templating systems of cetyltrimethylammonium bromide [$C_{16}H_{13}(CH_{3})_{3}$NBr, CTAB] with 1,3,5-trim­ethylbenzene (TMB) or a nonionic block copolymer of poly(ethylene oxide )-b-poly(propylene oxide )-b-poly(ethyl­ene oxide) ($EO_{20}PO_{70}EO_{20}$) were employed to improve the hydrothermal stability of the organic-inorganic self-assembly during the solid rearrangement process of the inorganic species. The mesoscopic ordering of the pore structure and geometry was identified by X-ray diffraction, small angle neutron scattering and electron microscopy.

Preparation of iron-doped titania from flocculated sludge with iron-titanium composite coagulant.

Kim, Jong Beom,Lee, Ki Won,Park, Se Min,Shon, Ho Kyong,Shahid, Mohammad,El Saliby, Ibrahim,Lee, Woong Eui,Kim, Geon-Joong,Kim, Jong-Ho American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.6

<P>The main drawback of flocculation process with dye wastewater is the large amount of unrecyclable sludge which needs disposal. A novel process using Ti-salt flocculation to purify wastewater was developed to produced sludge that can be calcined to produce titania. In this study, iron-doped TiO2 nanomaterial was successfully produced from sludge obtained by the flocculation of dye wastewater with a composite floculant including TiCl4 and FeSO4. The titania was characterised using scanning electron microscopy (SEM/EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), and the photodecomposition of acetaldehyde. The XDR results showed that the anatase and rutile structures were found after sludge calcination at 550 degrees C and 640 degrees C respectively. The elemental analyses were carried out using EDX. The rutile titania sample consisted of Ti (35.7 wt.%), Fe (14.7 wt.%), O (42.3 wt.%), P (2.6 wt.%) and Ca (4.7 wt.%). The photocatalytic activity was monitored for the photodecomposition of gas acetaldehyde. Iron-doped titania seems to play an important role in increasing the photocatalytic activity under UV light irradiation.</P>

Preparation of TiO2 nanoparticle from Ti-salt flocculated sludge with dye wastewater.

Kim, Jong Beom,Park, Hee Ju,Shon, Ho Kyong,Cho, Dong Lyun,Kim, Geon-Joong,Choi, Sung Woo,Kim, Jong-Ho American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.5

<P>Dye wastewater flocculation using TiCl4 and FeSO4 coagulants was studied for organic removal and precipitation efficiency. Moreover, TiCl4 was assessed in a pilot-scale flocculation process to investigate organic removal and solution pH effect. A large amount of TiO2 was produced from sludge of Ti-salt flocculation in dye wastewater. This flocculation process simultaneously reduces a large amount of sludge produced from wastewater. The TiO2 nanoparticle was characterized in terms of physical and chemical properties. Results showed that 77.6% of organic matter was removed from dye wastewater when using FeSO4 as coagulant, while TiCl4 degraded 75.9% of organic matter. On the other hand, floc precipitation efficiency was better for TiCl4 if compared with FeSO4. The optimum concentration of TiCl4 for pilot-scale flocculation was found to be equal to 2.1 g/L. DWT (Dye wastewater titania) size was 15-20 nm, mainly doped with carbon atoms and exhibited a dominant anatase structure. DWT was similar to P-25 in decomposing acetaldehyde under UV-irradiation and complete photocatalytic degradation was achieved after 140 min.</P>

PCR을 이용한 국내시장에 유통중인 유전자재조합 콩 및 가공식품의 모니터링

김묘영,김재환,김현중,박선희,우건조,김해영 한국응용생명화학회 2003 Applied Biological Chemistry (Appl Biol Chem) Vol.46 No.4

본 연구에서는 PCR을 이용하여 국내시장에 유통중인 원료콩과 가공식품에 epsps 또는 pat 유전자가 삽입된 유전자재조합 콩(GMS)의 사용여부를 모니터링하였다. 이러한 GMS의 검출을 위해 3쌍의 primer set을 제작하였고, 각각의 primer들은 GMS에 삽입된 유전자와 특이적으로 반응하여 PCR산물을 생성하였다. 2001년 표시제가 시행되기 이전에 생산된 총 가공식품과 이후의 제품에 대해 각각 모니터링을 수행하였으며, 표시제 이전에 생산된 제품의 경우 대부분의 미국산 원료에서 esps가 삽입된 GMS가 검출되었으나, 표시제 이후에는 검출되지 않았다. A method using PCR was developed for the monitoring of genetically modified soybean (GMS) and GMS derived foods utilized in the market. We designed 3 pairs of specific oligonucleotide primers based on epsps and pat inserted in GMS and ferritin gene as internal standards. Template DNAs isolated from soybean and processed foods were used for multiplex PCR with 3 primer sets. PCR, used with specific primer sets for GMS detection, showed the amplified DNA fragments with GMS template DNA. In this study, GMS containing epsps was detected from soy processed foods manufactured before GM food labeling system, however, GMS containing epsps or pat was not detected from soy processed foods manufactured after GM food labeling system.

Atomistic modelling for boron diffusion in strained silicon substrate

Kim, Young-Kyu,Yoon, Kwan-Sun,Kim, Joong-Sik,Kim, Han-Geon,Won, Taeyoung Taylor Francis 2008 Molecular simulation Vol.34 No.1

<P> We discuss the issue of boron diffusion in biaxial tensile strained {001} Si and SiGe layer with kinetic Monte Carlo (KMC) method. We created strain in silicon by artificially adding a germanium mole fraction to the silicon in order to perform a theoretical analysis. The strain energy of the charged defects was calculated from ab initio calculation whereas the diffusivity of boron was extracted from the Arrhenius formula. Hereby, the influence of the germanium content on the diffusivity of the impurity atom was estimated. Our KMC study revealed that the diffusion of the boron atoms was retarded with increasing germanium mole fraction in the strained silicon layer. Furthermore, we derived the functional dependence of the in-plane strain as well as the out-of-plane strain as a function of the germanium mole fraction, which is based on the distribution of equivalent stress along the Si/SiGe interface.</P>

빌트인 모터를 이용한 2축 제어 미세 가공기 개발

김건희,김효식,양순철,이상용,국명호,이선규,김윤중,홍권희 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

This paper describes development of low cost precision machine that has combined the Build-in Motor with a vacuum chuck. This study mainly aims to find out a cutting condition for maintaining optimum surface condition and to examine cutting characteristics of the precision machine that is equipped by diamond bites. The cutting materials is Al alloy. Several experiments were carried out to find out the main factors that affect the surface roughness such as principal axis RPM(rotation per minute), feeding speed, and cutting depth. As a result, we obtain The optimum cutting condition of the developed precision machine.

Structure and Acidity Modification of Mordenite Through Isomorphous Fe Substitution

Kim, Geon Joong,Ahn, Wha Seung 한국화학공학회 1992 NICE Vol.10 No.4

A series of Fe-modified mordenite were hydrothermally synthesized. The effects of substrate composition, aging time, reaction temperature, and reaction time upon the crystallization of the mordenite were investigated. Isomorphous substitution of Fe was confirmed by FT-IR and EPR analysis. Acid strength and acid sites distribution of each catalyst were measured by pyridine TPD, which showed that the number of strong acid sites in H-Fe-mordenite are smaller than in H-Al-mordenite. Structural characteristics and ermal stability were also examined using XRD, SEM and TG, Fe-substitution into the mordenite structure have resulted in substantial decrease in thermal stability HFe-mordenite catalysts showed high selectivity towards p-xylene in toluene alkylation and influent isomerization reaction, compared with those obtained using H-Al-mordenite because of lower concentration of strong acid sites. In addition, these H-Fe-modified mordenite showed little hexane cracking activity. Deactivation in both toluene alkylation and xylene isomerization reaction and coke formation over H-Fe-mordenite in these reactions were negligible.

High efficiency perovskite light-emitting diodes of ligand-engineered colloidal formamidinium lead bromide nanoparticles

Kim, Young-Hoon,Lee, Geon-Hui,Kim, Young-Tae,Wolf, Christoph,Yun, Hyung Joong,Kwon, Woosung,Park, Chan Gyung,Lee, T.-W Elsevier 2017 Nano energy Vol.38 No.-

<P><B>Abstract</B></P> <P>Formamidinium (FA, CH(NH<SUB>2</SUB>)<SUB>2</SUB>) lead bromide perovskite (FAPbBr<SUB>3</SUB>) nanoparticles (NPs) are promising emitters due to their high stability and ability to emit pure green color in both film and solution states. Even though various types of metal halide NP emitters in solution have shown high photoluminescence quantum efficiencies (PLQEs), electroluminescence efficiencies of the light-emitting diodes (LEDs) using the NP films are still much poorer, possibly due to the insulating ligands which can impede the charge injection and transport in films. Therefore, the organic ligand of NPs should be designed to facilitate charge injection and transport in LEDs. Here, we synthesize ligand-engineered colloidal FAPbBr<SUB>3</SUB> NPs at RT and demonstrate high efficiency perovskite NP LEDs based on the FAPbBr<SUB>3</SUB> NPs. Control of ligand length reduces trap-assisted recombination of carriers at the surface traps, and thus maximizes the PLQE of FAPbBr<SUB>3</SUB> NPs. Ligand engineering can also improve the charge injection and transport capability in FAPbBr<SUB>3</SUB> NP films. With this ligand engineering method, we achieve maximum current efficiency of 9.16cd/A in LEDs based on FAPbBr<SUB>3</SUB> NPs, which is the highest efficiency in FAPbBr<SUB>3</SUB> NP-LEDs to date. The ligand engineering method reported here can be a simple way to improve the luminescence efficiency of optoelectronic devices based on perovskite NP LEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We use ligand engineering to synthesize ligand-engineered colloidal FAPbBr<SUB>3</SUB> nanoparticles (NPs) at RT. </LI> <LI> Ligand engineering maximizes the luminescence efficiency and the charge injection/transport capability in FAPbBr3 NP film devices. </LI> <LI> We achieve high efficiency (9.16cd/A) in light-emitting diodes (LEDs) based on FAPbBr<SUB>3</SUB> NPs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Miniscalpel acupuncture points of the cervical region: A review

Kim, Ju-ran,Lee, Jung Hee,Gong, Han Mi,Jun, Seungah,Chung, Yeon-Joong,Park, Chung A,Choi, Seong Hun,Lee, Geon-Mok,Lee, Hyun-Jong,Kim, Jae Soo Korean AcupunctureMoxibustion Medicine Society 2017 대한침구의학회지 Vol.34 No.3

Objectives : We conducted a literature search to identify trends with respect to miniscalpel acupuncture points (MAPs) of the cervical region with the aim of providing guidance regarding miniscalpel acupuncture (MA) in the cervical region. Methods : We searched 2 overseas sites (PubMed and Google Scholar) and 5 domestic sites (NDSL, RISS, KISS, OASIS and Korean Traditional Knowledge Portal) for clinical trials of MA of the cervical region. The search terms used were "acupotomy or miniscalpel acupuncture or miniscalpel" and "cervical." Of 73 studies found, 11 were included in this review, 6 of which presented exact MAPs. Owing to the lack of data, we refer to 1 Korean and 4 Chinese articles to analyze the exact location and meaning of the MAPs used in the published studies and to propose other clinically applicable MAPs. Results : We identified 10 of the most commonly used MAPs in the published studies, including those located below the external occipital protuberance, 2-2.5 cm both side down of the external occipital protuberance, 4.5-5 cm both side down of the external occipital protuberance and C3-7 spinous process. Furthermore, we proposed 13 additional MAPs that can be used clinically. Conclusion : We hope that this study will form a basis for the development of MA and hope to improve the safety and reproducibility in future MA studies of the cervical region.

Flexible deep brain neural probe for localized stimulation and detection with metal guide

Kim, Jeong Hun,Lee, Geon Hui,Kim, Seohyeon,Chung, Hyo Won,Lee, Joong Hoon,Lee, Seung Min,Kang, Chong Yun,Lee, Sang-Hoon Elsevier 2018 Biosensors & bioelectronics Vol.117 No.-

<P><B>Abstract</B></P> <P>In this paper, we present the design, fabrication, and performance evaluation of a polyimide-based flexible neural probe for the precise site stimulation and recording in the deep brain. The probe consists of five electrodes: one for stimulation, another for ground and the other three for recording electrodes. This probe is designed to be foldable, enabling easy insertion into the deep brain via temporary tungsten guide sticks. Because of its small cross-sectional area and the flexibility of the polyimide, the probe causes minimum damage to the neural tissue and does not show any evidence of serious immune reactions such as high density of macrophage or microglia. Around the simulation electrodes, an additional ground electrode prevents the stimulation of the undesired sites in the brain. To ensure we stimulate the target point specifically, for instance STh in this study, we confirm through both finite element analyses and in vitro tests. With the additional ground electrodes, we observe the leakage power decreased by about 80%. To check the performance of the probe, we demonstrate animal experiments using rats, and neural spike signals from STh in the 7-mm deep brain are successfully recorded after implantation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Development of a flexible probe capable of limited stimulation and measurement in the deep brain. </LI> <LI> Easily reach the flexible probe to the desired position through the tungsten guide. </LI> <LI> Limited range of stimulation using ring-shaped ground electrode. </LI> </UL> </P>