• Journal of Chest Surgery
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• v.32 no.10
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• pp.910-915
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• 1999

Background: Positron emission tomography(PEFT) using fluorine-18 deoxyglucose(FDG), showing increased FDG uptake and retention in malignant cells, has been proven to be useful in differentiating malignant from benign tissues. We indertook the prospective study to compare the accuracy of the whole-body FDG PET with that of the conventional chest computed tomography(CT) for nodal staging of non-small-cell lung cancers(NSCLC). Material and Method: FDG PET and contrast enhanced CT were performed in 36 patients with potentially resectable NSCLC. Each Imaging study was evaluated independently, and nodal stations were localized according to the AJCC regional lymph nodes mapping system. Extensive lymph node dissection(1101 nodes) of ipsi- and contralateral mediastinal nodal stations was performed at thoracotomy and/or mediastinoscopy. Image findings were compared with the histopathologic staging results and were analyzed with the McNema test(p) and Kappa value(k). Result: The sensitivity, specificity, positive predictive value, and negative predictive value of CT for ipsilateral mediastinal nodal staging were 38%, 68%, 25%, 79%, and 61%, and those of PET were 88%, 71%, 47%, 95%, and 75%(p>0.05, K=0.29). When analyzed by individual nodal group(superior, aortopulmonary window, and inferior), the sensitivity, specificity, positive predictive value, and negative predictive value of CT were 27%, 82%, 22%, 85%, and 73%, and those of PET were 60%, 87%, 92%, and 82%(p<0.05, k=0.27). Conclusion: FDG PET in addition to CT appears to be superior to CT alone for mediastinal staging of non-small cell lung cancers.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.253-258
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• 2009

Bone scintigraphy using $^{99m}$Tc-labeled phosphate agents has long been the standard evaluation method for whole skeletal system. However, recent shortage of $^{99m}$Tc supply and advanced positron emission tomography (PET) technology evoked the attention to surrogate radiopharmaceuticals and imaging modalities for bone. Actually, fluorine-18 ($^{18}$F) was the first bone seeking radiotracer before the introduction of $^{99m}$Tc-labeled agents even though its clinical application failed to become pervasive anymore after the rapid spread of Anger type gamma camera systems in early 1970s. However, rapidly developed PET technology made us refocus on the usefulness of $^{18}$F as a PET tracer. Early study comparing $^{18}$F-Na PET scan and planar bone scintigraphy reported that PET has higher sensitivity and specificity in the diagnosis of metastatic bone lesions than planar bone scan. Subsequent reports comparing between PET and both planar and SPECT bone image also revealed better results of PET scan in similar study groups. Rapid clinical application of PET/CT also accumulated considerable amount of experiences in skeletal evaluation and this modality is known to have better diagnostic power than stand alone PET system as well as bone scan. Furthermore $^{18}$F-Na PET/CT revealed better or at least equal results in detection of primary and metastatic bone lesions compared with CT and MRI. Therefore, it is obvious that $^{18}$F-Na PET/CT has potential to become new imaging modality for practical skeletal evaluation so continuous and careful evaluation of this modality and radiopharmaceutical must be required.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.627-632
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• 2016

Ethyl methacrylate (EMA) monomer coupling onto the polyvinylidene fluoride (PVDF) film surface was attempted to enhance the interfacial adhesive force between PVDF-polyvinyl chloride (PVC) bilayer films via dielectric barrier corona discharge. The interfacial forces were quite enhanced when PVDF films were treated by corona discharge in an EMA 1% atmosphere. The contact angle of PVDF films decreased due to corona treatment. X-ray photoelectron spectroscopy (XPS) analysis showed that the carbon and oxygen content of the PVDF film surface increased with corona discharge while the fluoride content decreased. The curve fitting of XPS $C_{1s}$ peaks revealed that the non-polar C-C bonded carbon and oxygen-bonded carbon increased gradually with corona treatment, while the fluorine-bonded carbon decreased.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.407-413
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• 2003

The geology of the Apdong Nb-Ta deposit, is hosted by alkali metasomatites, consist of Upper Proterozoic sedimentary rocks, alkali syenites(Hoamsan intrusive) of Phyonggang Complex(late Paleozoic to early Mesozoic), Jurassic granite and Quaternary basalt. Alkali syenites are distinguished as alkali amphibole-pyroxene syenite, alkali amphibole-biotite syenite, biotite-nepheline syenite, biotite syenite, and quartz-alkali amphibole-pyroxene syenite. Alkali metasomatites are the products of intense post-magnatic metasomatism, and form the Nb-Ta ore bodies as the belt, irregular vein and lenticular types in the southern part of Hoamsan intrusive. The ore mineralization is characterized by the occurrence of pyrochlore, zircon, and small amounts of columbite, fergusonite. magnetite, fluorite, molybdenite, ilmenite, titanite, apatite, and monazite. Pyrochlore is one of the niobium/tantalum oxides and contains substantial amounts of rare earths and radioactive elements. The compositional varieties of pyrochlore can be defined: (1) enriched in tantalum, uranium and cerium, (2) substantially tantalum- and fluorine-poor, and (3) enriched in thorium or barium. The geochemical characteristics, ore textures and mineral occurrences indicate that alkali metasomatism of the mineralizing fluid was the dominant ore-forming process.

• Korean Journal of Health Education and Promotion
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• v.14 no.2
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• pp.149-158
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• 1997

This research reached conclusions to prepare indications for activity of Oral health Instruction of the first grade in an elementary school by several items of Oral examination and investigation. 1. The frequency of brushing their teeth of the children that were examined was generally two times a day(64.42%) : it showed that it was the highest after breakfast (30.08%), and hardly any brushed their teeth after lunch(6.36%). 2. Most of the toothbrushes used were for children(97.46%), and the proper time to change their toothbrushes was less than two months(65.25%), but 31.37% of them used their toothbrushes for more than three mouths. 3. They usually used toothpaste. Those using toothpaste were 64.41%. By the way, for adults was the percentage 31.36%, and for those including fluorine it was 74.58%. 4. They mainly ate cookies, beverages, (coke, cider, etc.), fruit, bread, milk and so on for their dessert. 5. Most students had dental plaque (95.76%) : 14.4% of then had calculus and 23.73% had gingivitis. 6. The results of disclosing showed that twelve anterior teeth were colored. The Mandible was comparatively more severe than the Maxillary in the colored -degree. the low -right - laterial incisor was the most severe and the right central incisor was the most severe of the Maxillary. 7. The pressure of tooth - brushing showed that half of the students brushed their teeth severely. The width of the brushing movemtnts was more than 8mm for 51.70%, 5-8mm for 33.05% and less than 5mm for 15.25% Therefore 66.5% of them were shown to move their brushes insufficiently or oppositely. 8. When they brushed, the children who opened their mouth while brushing were more than those who kept their mouth closed.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.362-366
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• 2014

Dye-sensitized solar cells (DSSCs) were synthesized using a $0.25cm^2$ area of a $TiO_2$ nanoparticle layer as the electrode and platinum (Pt) as the counter electrode. The $TiO_2$ nanoparticle layers (12 to 22 ${\mu}m$) were screen-printed on fluorine-doped tin oxide glass. Glancing angle X-ray diffraction results indicated that the $TiO_2$ layer is composed of pure anatase with no traces of rutile $TiO_2$. The Pt counter electrode and the ruthenium dye anchored $TiO_2$ electrode were then assembled. The best photovoltaic performance of DSSC, which consists of a $18{\mu}m$ thick $TiO_2$ nanoparticle layer, was observed at a short circuit current density ($J_{sc}$) of $14.68mA{\cdot}cm^{-2}$, an open circuit voltage ($V_{oc}$) of 0.72V, a fill factor (FF) of 63.0%, and an energy conversion efficiency (${\eta}$) of 6.65%. It can be concluded that the electrode thickness is attributed to the energy conversion efficiency of DSSCs.

• Polymer(Korea)
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• v.26 no.1
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• pp.9-17
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• 2002

The free radical bulk copolymerizations of perfluoroalkylethyl acrylate(FA) containing perfluoro group ($CF_3(CF_2)_nCH_2CH_2$-; n=5, 7, 9, 11) with styrene were conducted at $60^{\circ}C$ using AIBN as an initiator. Reactivity ratios($r_1$, $r_2$) were determined from monomer feed compositions and the NMR spectroscopically measured copolymer compositions using Kelen-Tudos method. The structures of copolymers were characterized with FT-IR and $^1H-NMR$ analysis. Their thermal properties investigated with DSC and TGA were decreased with increasing the content of fluorinated acrylate in the copolymer. Their surface free energies were calculated with measuring contact angles of the copolymers and PMMA blends with a small amount of them.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2895-2900
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• 2014

We fabricated quantum dot-sensitized solar cells (QDSSCs) using cadmium sulfide (CdS) and cadmium telluride (CdTe) quantum dots (QDs) as sensitizers. A spin coated $TiO_2$ nanoparticle (NP) film on tin-doped indium oxide glass and sputtered Au on fluorine-doped tin oxide glass were used as photo-anode and counter electrode, respectively. CdS QDs were deposited onto the mesoporous $TiO_2$ layer by a successive ionic layer adsorption and reaction method. Pre-synthesized CdTe QDs were deposited onto a layer of CdS QDs using a direct adsorption technique. CdS/CdTe QDSSCs had high light harvesting ability compared with CdS or CdTe QDSSCs. QDSSCs incorporating single-walled carbon nanotubes (SWNTs), sprayed onto the substrate before deposition of the next layer or mixed with $TiO_2$ NPs, mostly exhibited enhanced photo cell efficiency compared with the pristine cell. In particular, a maximum rate increase of 24% was obtained with the solar cell containing a $TiO_2$ layer mixed with SWNTs.

• Nuclear Engineering and Technology
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• v.41 no.4
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• pp.531-544
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• 2009

This paper is intended to provide key issues and current research outcomes on accelerator-based Boron Neutron Capture Therapy (BNCT). Accelerator-based neutron sources are efficient to provide epithermal neutron beams for BNCT; hence, much research, worldwide, has focused on the development of components crucial for its realization: neutron-producing targets and cooling equipment, beam-shaping assemblies, and treatment planning systems. Proton beams of 2.5 MeV incident on lithium target results in high yield of neutrons at relatively low energies. Cooling equipment based on submerged jet impingement and micro-channels provide for viable heat removal options. Insofar as beam-shaping assemblies are concerned, moderators containing fluorine or magnesium have the best performance in terms of neutron accumulation in the epithermal energy range during the slowing-down from the high energies. NCT_Plan and SERA systems, which are popular dose distribution analysis tools for BNCT, contain all the required features (i.e., image reconstruction, dose calculations, etc.). However, detailed studies of these systems remain to be done for accurate dose evaluation. Advanced research centered on accelerator-based BNCT is active in Korea as evidenced by the latest research at Hanyang University. There, a new target system and a beam-shaping assembly have been constructed. The performance of these components has been evaluated through comparisons of experimental measurements with simulations. In addition, a new patient-specific treatment planning system, BTPS, has been developed to calculate the deposited dose and radiation flux in human tissue. It is based on MCNPX, and it facilitates BNCT efficient planning based via a user-friendly Graphical User Interface (GUI).

• Journal of Powder Materials
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• v.25 no.1
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• pp.1-6
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• 2018

Uniform $TiO_2$ blocking layers (BLs) are fabricated using ultrasonic spray pyrolysis deposition (USPD) method. To improve the photovoltaic performance of dye-sensitized solar cells (DSSCs), the BL thickness is controlled by using USPD times of 0, 20, 60, and 100 min, creating $TiO_2$ BLs of 0, 40, 70, and 100 nm, respectively, in average thickness on fluorine-doped tin oxide (FTO) glass. Compared to the other samples, the DSSC containing the uniform $TiO_2$ BL of 70 nm in thickness shows a superior power conversion efficiency of $7.58{\pm}0.20%$ because of the suppression of electron recombination by the effect of the optimized thickness. The performance improvement is mainly attributed to the increased open-circuit voltage ($0.77{\pm}0.02V$) achieved by the increased Fermi energy levels of the working electrodes and the improved short-circuit current density ($15.67{\pm}0.43mA/cm^2$) by efficient electron transfer pathways. Therefore, optimized $TiO_2$ BLs fabricated by USPD may allow performance improvements in DSSCs.