• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.1-7
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• 2001

FGR is one of the most widely used methods of NOx reduction in the combustion process. It was investigated the effect of FGR, excess air ratio, peak temperature and firing rate on NOx emission in this study. 100kW burner and LNG were adopted in this experiment. NOx emission was notably decreased with the increase of FGR, however CO emission was also drastically increased in the 25% FGR. And excess air ratio, peak temperature and firing rate did not affect the NOx emission appreciably in the normal operating condition.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.390-395
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• 2003

The effect of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rate are experimentally investigated by using an once-through boiler with FGR system. The purpose of this study is to develop the FGR control system for reducing NOx in a boiler. Intake and exhaust oxygen concentrations, and equivalence ratio are applied to discuss the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that NOx emissions are decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.5
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• pp.405-415
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• 2007

The effects of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rates are experimentally investigated by using an once-through boiler with a FGR system. The purpose of this study is to develop the FGR control system for reducing $NO_x$ emissions in boilers. Intake and exhaust oxygen concentrations, and equivalence ratio are considered to figure out the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that $NO_x$ emissions are markedly decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated. One can also conclude that the reduction in $NO_x$ emissions is more considerably influenced by the variation of equivalence ratio due to the FGR rate than the fuel consumption rate.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.424-435
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• 2016

Background: The International Commission on Radiological Protection (ICRP) recommendations and the Federal Guidance Report (FGR) published by the U.S. Environmental Protection Agency (EPA) have been widely applied worldwide in the fields of radiation protection and dose assessment. The dose conversion coefficients of the ICRP and FGR are widely used for assessing exposure doses. However, before the coefficients are used, the user must thoroughly understand the derivation process of the coefficients to ensure that they are used appropriately in the evaluation. Materials and Methods: The ICRP provides recommendations to regulatory and advisory agencies, mainly in the form of guidance on the fundamental principles on which appropriate radiological protection can be based. The FGR provides federal and state agencies with technical information to assist their implementation of radiation protection programs for the U.S. population. The system of radiation dose assessment and dose conversion coefficients in the ICRP and FGR is reviewed in this study. Results and Discussion: A thorough understanding of their background is essential for the proper use of dose conversion coefficients. The FGR dose assessment system was strongly influenced by the ICRP and the U.S. National Council on Radiation Protection and Measurements (NCRP), and is hence consistent with those recommendations. Moreover, the ICRP and FGR both used the scientific data reported by Biological Effects of Ionizing Radiation (BEIR) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) as their primary source of information. The difference between the ICRP and FGR lies in the fact that the ICRP utilized information regarding a population of diverse races, whereas the FGR utilized data on the American population, as its goal was to provide guidelines for radiological protection in the US. Conclusion: The contents of this study are expected to be utilized as basic research material in the areas of radiation protection and dose assessment.

• Journal of Ginseng Research
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• v.42 no.3
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• pp.312-319
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• 2018

Background: Previous studies have shown that both ginseng root and ginseng berry exhibit antiobesity and antidiabetic effects. However, a direct comparison of the efficacy and mechanisms between the root and the berry after oral administration remains to be illuminated. Methods: In this study, we observed the effects of fermented ginseng root (FGR) and fermented ginseng berry (FGB) on obesity and lipid metabolism in high-fat diet induced obese mice. Results: FGR and FGB significantly inhibited the activity of pancreatic lipase in vitro. Both FGR and FGB significantly suppressed weight gain and excess food intake and improved hypercholesterolemia and fatty liver, while only FGR significantly attenuated hyperglycemia and insulin resistance. Both FGR and FGB significantly inhibited the mRNA expression of Ldlr and Acsl1 while FGR also significantly inhibited expression of Cebpa and Dgat2 in liver. FGR significantly decreased the epididymal fat weight of mice while FGB significantly inhibited the mRNA expression of genes Cebpa, Fas, Hsl, Il1b, and Il6 in adipose tissue. Conclusion: Saponin from both FGR and FGB had a beneficial effect on high-fat diet-induced obesity. Compared to FGB, FGR exhibited more potent antihyperglycemic and antiobesity effect. However, only FGB significantly inhibited mRNA expression of inflammatory markers such as interleukins $1{\beta}$ and 6 in adipose tissue.

• Korean Journal of Optics and Photonics
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• v.7 no.1
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• pp.66-71
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• 1996

We analyzed and fabricated InP/InGaAs avalanche photodiode (APD) having floating guard ring (FGR). Since the FGR-APD is very simple to fabricate and highly reliable, the fabrication of FGR-APD and its application to the optical receiver are very useful and interesting. A double zinc diffusion was employed to fabricate and one dimensional electric field analysis was used for design. Two dimensional gain measurement showed that the FGR suppressed gain at the curved edge, indicating the successful behavior as a guard ring. The fabricated device had 35 GHz of gain-bandwidth product, and showed the sensitivity of -31.9 dBm at a bit error rate of $10^{-9}$ when it was applied to a 2.5 Gbps optical receiver.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.19-20
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• 2012

Flue gas recirculation(FGR) is applied to sintering process to cope with issues including plant efficiency and environmental effects. However, it inevitably brings changes of incoming and outgoing gas conditions as plant configurations. Objective of this study was to build a process model for a sintering bed using a flowsheet process simulator and obtain information of mass and heat balance for gas flows over various process configurations with FGR.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.254-263
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• 2006

Manganese has a role as both toxic and essential in humans. Manganese is also an essential component in the welding because it increases the hardness and strength, prevents steel from cracking of welding part and acts as a deoxidizing agent to form a stable weld. In this study, manganese generation rate and its content was determined in flux cored arc welding on stainless steel. Domestic two products and foreign four products of flux cored wires were tested in the well designed fume generation chamber as a function of input power. Welding fume was measured by gravimetric method and metal manganese was determined by inductively coupled plasma-atomic emission spectrophotometer. The outer shell of the flux cored wire tube and inner flux were analyzed by scanning electron microscopy to determine their metal compositions. Manganese generation rate($FGR_{mn}$) was increased as the input power increased. It was 16.3 mg/min at the low input power, 38.1 mg/min at the optimal input power, and up to 55.4 mg/min at the high input power. This means that $FGR_{mn}$ is increased at the work place if welder raise the current and/or voltage for the high productivity. The slope coefficient of $FGR_{mn}$ was smaller than that of the generation rate of total fume(FGR). Also, the correlation coefficient of $FGR_{mn}$ was 0.65 whereas that of FGR is 0.91. $FGR_{mn}$ was equal or higher in the domestic products than that of the foreign products although FGR was similar. From the electron microscopic analytical data, we concluded that outer shell of the wire was composed mainly of iron, chromium, nickel and less than 1.2 % of manganese. There are many metal ingredients such as iron, silica, manganese, zirconium, titanium, nickel, potassium, and aluminum in the inner flux but they were not homogeneous. It was found that both $FGR_{mn}$ and content of manganese was higher and more varied in domestic flux cored wires than those of foreign products. To reduce worker exposure to fumes and hazardous component at the source, further research is needed to develop new welding filler materials that improve the quality of flux cored wire in respect to these points. Welder should keep in mind that the FGR, $FGR_{mn}$ and probably the generation rate of other hazardous metals were increased as the input power increase for the high productivity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.263-273
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• 2016

The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing $NO_x$ emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between $0^{\circ}$ and $90^{\circ}$, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and $NO_x$ emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.

• Journal of the Korean Society of Combustion
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• v.21 no.1
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• pp.38-45
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• 2016

Flame characteristics and NO emission behavior in $CH_4$/air-air premixed counterflow flames with applying FIR and FGR with $CO_2$ and $H_2O$ were investigated numerically by varying the ratios of FIR and FGR as well as global strain rate. Chemical effects of added $CO_2$ and $H_2O$ via FIR and FGR were analyzed through comparing flame characteristics and NO behaviors from real species($CO_2$ and $H_2O$) with those from their artificial species($XCO_2$ and $XH_2O$) which have the same thermochemical, radiative, and transport properties to those for the real species. The results showed that flame temperature and NO emission with FIR varied much more sensitively than that with FGR. Those varied little irrespective of adding $CO_2$, $H_2O$, and their artificial species to the fuel stream via FIR. However, Those were varied complicatedly by chemical effects of added $CO_2$ and $H_2O$ via FGR. Detailed analyses for them were made and discussed.