• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.20-23
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• 2012

In this paper, we investigated the device performance on fluorine implantation, hot carrier reliability and RTS (random telegraph signal) noise characteristics of NMOSFETs. The capacitance of the fluorine implanted NMOSFET decreased due to the increase of the gate oxide thickness. RTS noise characteristics of the fluorine implated NMOSFET was improved approximately by 46% due to the decrease of trap density at Si/$SiO_2$ interface. The improved gate oxide quality also results in the longer hot carrier life time.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.550-555
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• 1998

For fluoro-quinolone carboxylic acid derivatives, one bond carbon-fluorine coupling constants are ranged from 249 Hz to 257 Hz regardless of positions. But geminal and vicinal carbon-fluorine coupling constants vary according to positions, namely, geminal coupling constants are ranged from 6 Hz to 23 Hz, and vicinal coupling constants are ranged from 1.9 Hz to 7 Hz. In cases of proton-fluorine couplings, three bond coupling constants are ranged from 9 Hz to 10.3 Hz, and four bond coupling constants ate ranged from 6 Hz to 8.3 Hz.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.59-68
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• 2011

Objectives : To investigate the knowledge and recognition level of fluorine by teaching career among class teachers, who are primarily responsible for oral health education, despite lack of expertise in oral health, by playing a model role for students through continuous contacts with them, and provide basic elementary data about accurate knowledge and how to correctly use fluorine remarkably effective in preventing dental caries. Methods : A self-administered survey was conducted with 539 teachers at 21 elementary schools in Jinhae City from September 1 to October 15, 2010, drawing the following conclusions. Results : 1. As for the channel for acquiring knowledge of oral health, the highest frequency was found in health programs for respondents with less than 9 years of career, in dental clinics for those with 20 to 29 years of career, and in PR booklets for those with 10 to 19 years and 30 years and longer of career. 2. Use of fluorine-containing toothpaste and fluorine spread is very effective and effective in preventing dental caries got 64.9%, 72.2%, 72.3%, 77.7% and 54.0%, 63.1%, 62.2%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 3. Intake of fluoride and toothbrushing with fluoric solution is very effective and effective in preventing dental caries got 33.3%, 40.1%, 39.5%, 55.3% and 50.0%, 54.9%, 48.8%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 4. Use of fluoric tablets is very effective and effective in preventing dental caries got 32.9%, 36.0%, 36.1%, 47.3%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 5. Most of the elementary school teachers knew the fact that fluorine increases dental resistance to cavity and prevents bacterial growth but gave incorrect responses to properties of becoming basic nutrients or inducing recalcification. Conclusions : Various types of application of fluorine during the elementary-level childhood experiencing the most frequent dental caries will be very useful in improving oral health in the future. It is necessary to enable class teachers to get correct recognition of fluorine through supplementary and job training based on technical knowledge and various educational materials so that they, who are directly responsible for health management through continuous contacts with students, can understand how to correctly use fluorine and get accurate knowledge.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.177-184
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• 2014

In chemical vapor deposition(CVD) tungsten silicide(WSix) dual poly gate(DPG) scheme, we observed the fluorine effects on gate oxide using the electrical and physical measurements. It is found that in fluorine-rich WSix NMOS transistors, the gate thickness decreases as gate length is reduced, and it intensifies the roll-off properties of transistor. This is because the fluorine diffuses laterally from WSix to the gate sidewall oxide in addition to its vertical diffusion to the gate oxide during gate re-oxidation process. When the channel length is very small, the gate oxide thickness is further reduced due to a relative increase of the lateral diffusion than the vertical diffusion. In PMOS transistors, it is observed that boron of background dopoing in $p^+$ poly retards fluorine diffusion into the gate oxide. Thus, it is suppressed the fluorine effects on gate oxide thickness with the channel length dependency.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.9
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• pp.623-627
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• 1999

We report a new in-situ fluorine passivation method without in implantation by employing excimer laser annealing of $SiO_{x}F_{y}$/a-Si structure and its effects on p-channel poly-Si TFTs. The proposed method doesn't require any additional annealing step and is a low temperature process because fluorine passivation is simultaneous with excimer-laser-induced crystallization. A in-situ fluorine passivation by the proposed method was verified form XPS analysis and conductivity measurement. From experimental results, it has been shown that the proposed method is effective to improve the electrical characteristics, specially field-effect mobility, and the electrical stability of p-channel poly-Si TFTs. The improvement id due to fluorine passivation, which reduces the trap state density and forms the strong Si-F bonds in poly-Si channel and $SiO_2/poly-Si$ interface. From these results, the high performance poly-Si TFTs canbe obtained by employing the excimer-laser-induced fluorine passivation method.

• Economic and Environmental Geology
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• v.52 no.4
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• pp.275-290
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• 2019

Geochemical study was conducted to elucidate the origin of fluorine (F) distributed in the rocks within the four areas of Yongyudo and Sammokdo, Incheon, which have been used as the source area of land reclamation for the $3^{rd}$ and $4^{th}$ stage construction sites of the Incheon International Airport. The main geology of the study area is Triassic biotite granite. Fluorine is contained at high levels in biotite granite, mylonite, and dykes (andesite and, basaltic-andesite). Furthermore, the higher concentrations of fluorine in the biotite granite can be contributed to fluorite. The results of microscopic analyses reveal that the fluorite was mostly observed as small vienlets together with quartz. This features support that fluorite was naturally formed due to the secondary process of hydrothermal fluids. In addition, fluorine was investigated to be highly enriched in a large amount of mica within the veins. In the case of mylonite, a high levels of fluorine was contributed to a large amount of sericite. The sericites contained in the mylointe, differently to those of the biotite granite, filled the micro-fractures of quartz formed as a result of mylonitization and included small cataclastic quartz grains. This indicates that fluorine was naturally enriched due to the alteration of hydrothermal fluids filling fractured zones formed by mylonitization. Consequently, the results of petrological and mineralogical study confirm that the fluorine distributed in the rocks within the Yongyudo and Sammokdo originated naturally.

• Analytical Science and Technology
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• v.33 no.6
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• pp.262-273
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• 2020

A fluorine content analysis method for krill oils, which is a representative oil formulation in foods, was developed in compliance with the Korea Food and Drug Ministry's "Guidelines for Validation of Testing Methods Related to Food". Using this method for krill oils, the presence of impurities was evaluated via combustion-ion chromatography (C-IC). A review of published technical data on fluorine in krill oils showed that while the traditional wet potentiometric method was typically used, it was not reliable. Moreover, there was no food testing/analysis laboratory in Korea to perform a fluorine test analysis on such an oil matrix. Therefore, we identified halogen (fluorine) tests, developed to national and international standards, and developed a test method suitable for krill oils by selecting a C-IC method that is sufficiently applicable to the oil matrix. Based on the characteristics of the oil matrix, the optimal test method was established through various experiments by reviewing the concerns related to loss and interference in the preparation and introduction of samples. The fluorine content test was carried out on 11 krill oil products that were purchased online. Most products (with the exception of only one) were found to contain less than the reporting limit obtained by the test method. Furthermore, after additional testing, a high fluorine content of approximately 2,000 ~ 3,000 mg/kg was detected on the krill surface, although the concentration varied depending on the area of the krill. A comparison with samples from two ISO/IEC 17025 testing laboratories confirmed that there was no significant difference in the statistical analysis results obtained by ANOVA among the three laboratories. A testing guide for fluorine content analysis was completed.

• Journal of Soil and Groundwater Environment
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• v.15 no.5
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• pp.8-15
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• 2010

The purpose of this research is to check the validation of an auto-analysis method combined with aqua regia digestion apparatus for improvement of water distillation method used as a fluorine test of soil. Fluorine contents of CaO used in the pretreatment course of water distillation method were 120 mg/kg ~ 5,064 mg/kg at the blank test, which was exceeded up to maximum 12.5 times of the soil standard, so it was estimated due to a effect of fluorine existing as impurities of CaO. The recovery test of the same samples indicated that water distillation method and auto-analysis method were 134.5mg/kg and 161.7mg/kg respectively, the recovery ratio of the latter was 16.8% higher than the formal. The validation test of two methods satisfied the standard, but auto analysis method was excellent more than distillation method. Also, auto analysis method could save a analysis time up to maximum 4.7 times by comparison with water distillation method.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.345-351
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• 2007

The research which it sees will confront to the coating with paint material and a coating with paint public law application of the river bridge and it will present it will sleep and it will execute, it will reach and a comparison - an analysis from the research which it tries to respect middle of special environment the polyurethane system which is a method coating with paint system and fluorine resin system, against a ceramic system it executed more an objectivity and rational fundamental data. With research method against each coating with paint evening sunlight a research investigation material and structure, it separated with spatial-temporal characteristic and economic viewpoint it executed. When considering overview from material viewpoint, fluorine resin system ceramic system polyurethane system pure with it is judged with the fact that it is excellent. There is a possibility of saying that the coefficient of friction of the fluorine resin system which uses the weapon quality zinc end coating compound ever so hard and polyurethane system is excellent ceramic system than from structure viewpoint. That fluorine resin system = polyurethane system ceramic system pure with it is excellent, it is judged from spatial-temporal characteristic viewpoint. It measures but it considered an internal troubles year grudge in the standard which becomes disturbance the place where it executes the market the expectation life person of the general bridge against 100 years the result fluorine resin system polyurethane system ceramic system which compares a materials unit cost pure with it appeared.

• Journal of Electrochemical Science and Technology
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• v.5 no.3
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• pp.87-93
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• 2014

The fluorine-substituted $0.3Li_2MnO_3{\cdot}0.7Li[Mn_{0.60}Ni_{0.25}Co_{0.15}]O_{2-x}F_x$ cathode materials were synthesized by using the transition metal precursor, $LiOH{\cdot}H_2O$ and LiF. This was to facilitate the movement of lithium ions by forming more compact SEI layer and to reduce the dissolution of transition metals. The $0.3Li_2MnO_3{\cdot}0.7Li[Mn_{0.60}Ni_{0.25}Co_{0.15}]O_{2-x}F_x$ cathode material was sphere-shaped and each secondary particle had $10{\sim}15{\mu}m$ in size. The fluorine-substituted cathodes initially delivered low discharge capacity, but it gradually increased until 50th charge-discharge cycles. These results indicated that fluorine substitution gave positive effects on the structural stabilization and resistance reduction in materials.