• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.309-313
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• 2008

We studied the sapphire and germanium fibers to determine which optical fiber best transmits Erbium:YAG laser for intracorporeal lithotripsy. Human calculi were ablated with an Erbium:YAG laser in contact mode using two fibers. Optical outputs at the distal end of fibers were measured before and after laser lithotripsy. Upon the irradiation on the calculus with the 50 mJ and 100 mJ pulse energy, the output energy at the distal end of germanium fiber declined to approximately 50% of the input energy. For the sapphire fiber, the output energy at the distal end remained unchanged with 100 mJ input energy; however the output energy had dropped to 50% for 200 mJ input energy. In order to examine how the types of target tissue affect the fiber damage, the sapphire fiber was tested for the irradiation on soft tissue and water as well. No energy decline was observed during soft tissue and water irradiation. We also characterized ablation craters with both optical fibers. Both fibers produced similar craters on calculi in terms of depth and diameter. Sapphire fibers are better suited than germanium fibers for Erbium:YAG lithotripsy in terms of the fiber damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.1150-1154
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• 2002

This study was carried out to evaluate the nutritional value of soybean sprouts cultured in water with germanium. In the germanium treated soybean sprouts (GSP), the contents of moisture and ash were higher than those of control group (germanium non-treated soybean sprouts), with 88.7~90.2% and 16~24%, respectively. The contents of dietary fiber, vitamin C and total phenol of GSP were also higher than those of control group especially with more than 20~40% in total phenol being contained. Minerals of soybean sprouts were considerably increased during S-day cultivation. Of minerals, the contents of calcium and iron in GSP were higher than in the control. In particular there was no germanium in control group, but on the other hand, GSP had germanium of 159 ppm. Therefore, it may be suggested that, soybean sprout with germanium is better than soybean sprout without germanium in terms of nutrition.

• Journal of IKEEE
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• v.14 no.4
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• pp.263-269
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• 2010

In this paper, we present high temperature characteristics of a tunable all-optical filter using fiber Bragg grating(FBG) filter in Ge doped and Ge & B co-doped fiber, including peak reflectivity, bandwidth and various normalized refractive index change with temperature variation. The reflection spectrum of a FBG filter with refractive index change is affected by its thermal stability. Consequently Ge doped FBG tunable filter has a better thermal stability than Ge & B co-doped FBG tunable filter. Also, both FBG tunable filters show good thermal stability up to about $500^{\circ}C$.

• Proceedings of the Korean Fiber Society Conference
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• 1999.04a
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• pp.277-282
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• 1999

• Proceedings of the Membrane Society of Korea Conference
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• 2000.04a
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• pp.23-26
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• 2000

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.993-995
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• 1998

We fabricated fiber gratings with three different Ge-doped fibers exposed to 60atm pressure of Hz gas at 90"C for different times and studied the effects of Ge-doping concentration and $H_2$ loading time on the growth of gratings. According to experiments. the growing effect of hydrogen loading on high Ge-doped fiber was great.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.240-241
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• 2000

Sapphire fiber has been used to provide an optical path for the total radiation pyrometry. In measuring the temperature, we use the two-color detector, which consists of a high-performance Silicon detector mounted in a "sandwich" configuration over a Germanium detector. Sapphire fiber can withstand high temperature in the molten steel for two and a half hours. The maximum value of the error is the $\pm$2.5$^{\circ}C$ in the range of 152$0^{\circ}C$~1$600^{\circ}C$. This paper presents the simple scheme for measuring the molten steel temperature in the blast furnace of the iron ＆ steel making process.g process.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.2
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• pp.224-234
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• 2013

This study investigates the fabrication of core-sheath nanocomposite fibers by locating germanium (Ge) and silicon dioxide ($SiO_2$) nanoparticles selectively in the sheath layer by co-axial electrospinning. Co-axially spun fibers were prepared by electrospinning a pure PVA solution and Ge/$SiO_2$/PVA solution as the core and sheath layer, respectively. Core-sheath nanocomposite fibers were electrospun under a variety of conditions that include various feed rates for the core and sheath solutions, voltages, and concentric needle diameters, in order to find an optimum spinning condition. Ge/$SiO_2$ nanocomposite fibers were also prepared by uniaxial electrospinning to compare fiber morphology and nanoparticle distribution with core-sheath nanofibers. Using scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis, it was demonstrated that the co-axial approach resulted in the presence of nanoparticles near the surface region of the fibers compared to the overall distribution obtained for uni-axial fibers. The co-axially electrospun Ge/$SiO_2$/PVA nanofiber webs have possible uses in high efficiency functional textiles in which the nanoparticles located in the sheath region provide enhanced functionality.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2182-2189
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• 2024

The high-purity germanium gamma-ray spectrometer was used to measure the radioisotope in surface water of lakes in a Chinee petroleum industrial area. 92 samples were collected from surface water of three lakes. Activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K in three lakes were measured, distributed in the range of 101.8-209.4, 192.1-224.9 and 335.0-548.9 mBq/L, respectively. Results were all within the limits of WHO and China. Potential environmental and health risks were assessed by calculating some radiation hazard indicators, radium equivalent index, annual effective dose, excess lifetime cancer risk, absorbed dose rate, external hazard index, internal hazard index, annual gonadal dose equivalent, activity utilization index and representative gamma index, which ranged 0.38-0.54 Bq/L, 0.06-0.08 mSv/y, 0.23 × 10^-3-0.31 × 10^-3, 0.17-0.24 nGy/h, 1.01 × 10^-3-1.46 × 10^-3, 1.55 × 10^-3-2.02 × 10^-3, 1.16-1.66 μSv/y, 3.13 × 10^-3-4.45 × 10^-3 and 2.60 × 10^-3-3.77 × 10^-3. The results were all at acceptable levels, meaning no impact on human health. The relationship between the electrical conductivity of surface water and the activity concentration of ²³²Th, ²²⁶Ra and ⁴⁰K was evaluated. The electrical conductivity value was 0.241-0.369 mS/cm, showing a significant correlation coefficient between ²²⁶Ra and ⁴⁰K and electrical conductivity. Multivariate statistical methods were used to determine the relationship between the activity concentrations of ²³²Th, ²²⁶Ra, and ⁴⁰K, radiation hazard indicators and electrical conductivity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1397-1405
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• 2009

This study was to investigate food components of Bigum spinach growing in Jeonnam Shinan. The samples used in this study were Pohang spinach of inland and jo-saeng, chung-saeng, man-saeng, chungman-saeng spinach of Bigum located on Jeonnam Shinan. We analyzed proximate composition, mineral content, germanium, organic acid, free sugar, vitamin A, C, and E contents. We conducted the sensory evaluation after blanching and color changes of before and after blanching of 5 kinds of spinach. The results were as follows: moisture and ash contents were significantly higher in Pohang spinach than Bigum spinach. Crude protein, carbohydrates and crude fiber contents were higher in Bigum spinach than Pohang spinach. In mineral contents, potassium and zinc contents were higher in Pohang spinach than Bigum spinach whereas calcium, iron, magnesium, manganese, sodium contents were higher in Bigum spinach than Pohang spinach. Germanium contents was 14.06$\sim$27.16 ppb in Bigum spinach whereas not detected in Pohang spinach. In organic acid contents, man-saeng and jo-saeng of Bigum spinach were high in oxalic acid, citric acid, malic acid and formic acid contents. Succinic acid and acetic acid contents were high in Pohang spinach. Almost all free sugars were higher in Bigum spinach, especially jo-saeng and man-saeng, than Pohang spinach except lactose. Vitamin A contents was similar with Pohang and Bigum spinach except chung-saeng but vitamin C and E contents were higher in Bigum spinach than Pohang spinach. Color L (light) after blanching was significantly higher in chungman-saeng than other spinaches. Color a (redness) was significantly lower in chung-saeng and man-saeng than others and chungman-saeng was significantly higher than others. Color b (yellowness) was low in man-saeng and high in jo-saeng of Bigum spinach. In case of sensory properties after blanching, taste, sweet, overall preference were significant higher in Bigum spinach except chung-saeng than Pohang spinach.