• Resources Recycling
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• v.27 no.5
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• pp.69-76
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• 2018

For the purpose of optimizing the counter current extraction process for separation of [Sm] and [Pr, Nd] group in hydrochloric acid solution using Cyanex 572 as an extractant, the theory of Xu Guangxian was derived for calculating the optimized extraction factors. From the basic batch test result, the separation factor of [Sm]/[Pr, Nd] was 14.59 at pH 1.75 in extraction process and 14.61 at 0.01 M HCl in scrubbing process. The process parameters can be calculated using a theory of optimum extraction ratio. From the result of calculation, the total extraction and scrubbing stage numbers at counter current process were 11 and for maintain extraction ratio the flow rate ratio of feed solution, solvent solution, scrubbing solution was 6.25 : 1.74 : 5.80 using 0.1 M HCl.

• Journal of Powder Materials
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• v.9 no.6
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• pp.381-393
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• 2002

Recent developments in nanocrystalline and nanocomposite rare earth-transition metal magnets are reviewed and emphasis is placed on research work at IFW Dresden. Principal synthesis methods include high energy ball milling, melt spinning, mold casting and hydrogen assisted methods such as reactive milling and hydrogenation-disproportionation-desorption-recombination. These techniques are applied to NdFeB-, PrFeB- and SmCo-type systems with the aim to produce high remanence magnets with high coercivity. Concepts of maximizing the energy density in nanostructured magnets by either inducing a texture via anisotropic HDDR or hot deformation or enhancing the remanence via magnetic exchange coupling are evaluated. With respect to high temperature applications melt spun $Sm(Co_{0.74}Fe_{0.1}Cu_{0.12}Zr_{0.04})_{7.5}$ ribbons were prepared, which showed coercivities of up to 0.53 T at 50$0^{\circ}C$. Partially amorphous $Nd_{60}Fe_xCo_{30-x}Al_{10}(0{\leq}x{\leq}30)$ alloys were prepared by copper mold casting. The effect of transition metal content on the glass-forming ability and the magnetic properties was investigated. The $Nd_{60}Co_{30}Al_{10}$ alloy exhibits an amorphous structure shown by the corresponding diffraction pattern. A small substitution of Co by 2.5 at.% Fe results In the formation of Fe-rich crystallites embedded in the Nd-rich amorphous matrix. The Fe-rich crystallites show hard magnetic behaviour at room temperature with a coercivity value of about 0.4 T, relatively low saturation magnetization and a Curie temperature of 500 K.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.270-273
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• 2007

We have investigated the output characteristics of the 946 nm Nd:YAG laser which is longitudinally pumped by a fiber coupled laser diode. The temperature of a Nd:YAG crystal mount was kept constant by a controller with thermoelectric cooler. As a result, we measured more intense output at a low temperature, and then the maximum output power was measured to be 870 mW when the pumping power and the temperature were 9.95 W and $5^{\circ}C$, respectively. It appeared that output was decreased above 10 W pump power because of the thermal effects in gain medium.

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1038-1042
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• 1998

Mechanical grinding and subsequent annealing were applied to the $Nd_5Pr_7Fe_{82}B_6$ and $Nd_{12}Fe_{82}B_6$ ingots, and the crystal structure and magnetic properties were investigated. After 330 hours milling, the particles with $2~3\mu\textrm{m}$average size were identified to be composed of very fine crystallites judging from the x-ray diffraction patterns. The intrinsic coercivity of 18.36 ~ 18.79 kOe and the maximum energy product of 8.32-8.38 MGOe were obtained by the annealing of the milled powders at $600^{\circ}C$ for 2 hours. Annealing at a higher temperature resulted in the improved magnetic properties. However it was revealed that the control of the micro-crystallites formed during the grinding process was more important to get an optimized magnetic properties than the annealing condition.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.87-91
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• 2003

This study was carried out to investigate the heavy metal distributions of soils in the vicinity of Shi-Hwa industrial complex region, where the air pollutants from industrial area could affect the soil environment of near residential and green areas. The ranges of contents of As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn in soils were 0.58~3.81, ND~0.91, 0.15~6.33, ND~l.86, 0.14~110.27, ND~l.17, 0.04~10.59, 1.16~86.48 and 1.83~212.65 mg/kg, respectively. For all industrial, residential and green areas, the heavy metal contents were much lower than the standard of Korean Soil Environmental Preservation Act or the critical concentration which phytotoxicity is considered to be possible. Mean values of contents of As were similar in industrial, residential and green areas. However, the mean values of contents of Cd and Cr in industrial area were higher 10 and 5 times than those in residential and green area, respectively. And also the mean values of contents of Co, Cu, Hg, Ni, Pb and Zn in industrial area were higher 2~3 times than those in residential and green area.

• Journal of the Korean Magnetics Society
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• v.2 no.1
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• pp.44-49
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• 1992

Magnetic properties and microstructures of $Nd_{12}Fe_{80}B_{6}(Nb,\;M)$ (M=Ti/Cu/Ga) melt-spun ribbons prepared by single wheel technique have been studied. The results of microstructural study have shown that Ga is effective for the orientation of c-axis normal to the ribbon plane. The Ga-added melt-spun ribbon, $Nd_{12}Fe_{80}B_{6}(Nb,\;Ga)$, quenched at $V_{s}=17.9\;m/s$ was mostly composed of fine grains of about 30 nm in size with the textured free-side surface. The powder of this ribbon aligned in mag-netic field showd a high remanence of 0.87 T which was about 5 % higher than that of ribbon itself. It is believed that there is a possibility to fabricate a new type of HIREM melt-spun ribbon with highly textured free-side surface.

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.276-280
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• 2009

A Cr:YAG crystal was used as a saturable absorber for passive Q-switching of a Nd:$YVO_4$ laser which was pumped by a 1-W continuous wave laser diode. The first surface of the Cr:YAG was high-reflection coated for the pump wavelength. The high-reflection coating improved the absorption efficiency of the pump beam in the Nd:$YVO_4$ through double pass absorption. It also prevented pump beam induced partial bleaching of the Cr:YAG. The peak-to-peak pulse fluctuation of passively Q-switched laser output was approximately 4 %. The minimum pulse-width was measured to be 7.11 ns. Also, the average pulse repetition rate was 9 kHz and the maximum output power was 16.27 mW.

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.320-324
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• 2005

The core loss of $3\%$ SiFe is strongly dependent on silicon content, impurities, permeability, and domain structure of the SiFe. Domain refining has been proved to be very good method for reduction of core loss in high permeability grain oriented SiFe, and laser scribing is well-blown as an effective and industrially important method of domain refinement. In this work, magnetic domain refinement has been carried out by using a pulsed Nd : YAG laser, and the core losses have been measured and analyzed to and optimal parameters of the laser treatment. The laser hem was focused with a spot size of $100{\mu}m$ and pulse energy of 10${\~}$35mJ and the lines were scribed with a period of ${\~}$5mm. The core loss was improved up to $17\%$ with 30 ns-Nd : YAG laser beam in $3\%$ SiFe.

• Medical Lasers
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• v.8 no.1
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• pp.24-27
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• 2019

Seborrheic keratoses (SKs) have been treated with non-ablative longpulsed (LP) lasers, including LP 532-nm neodymium (Nd): yttrium aluminum garnet (YAG), LP 695-nm ruby, LP 755-nm alexandrite (Alex), and LP 1,064-nm Nd:YAG lasers, with a pulse durations of 1-300 msec. Dual-wavelength LP 755-nm Alex/1,064-nm Nd:YAG laser systems have been used to remove hair follicles and treat various vascular and pigmented disorders by sequentially delivering two pulses of different wavelengths with interpulse intervals in the millisecond range. This paper reports the case of a female patient with multiple, discrete, light brown SKs on the dorsum of both hands that were treated effectively with one session of dual-wavelength LP 1,064-nm Nd:YAG/755-nm Alex laser treatment. The treatment settings for the LP Nd:YAG laser were comprised of a wavelength of 1,064 nm, fluence of 50 J/cm², pulse duration of 5 msec, and beam size of 3 mm. The settings for the LP Alex laser were comprised of a wavelength of 755 nm, fluence of 50 J/cm², pulse duration of 5 msec, and beam size of 3 mm. A hybrid mode was used to automatically deliver LP Nd:YAG and LP Alex laser pulses in succession at interpulse intervals of 20 msec. Six weeks after treatment, the patient exhibited remarkable improvement of the light brown seborrheic keratoses and was satisfied with the results.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.954-960
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• 2003

To develop mobile phone antenna modules, glass-ceramics composites that are 20∼80 dielectric constant materials which has been fabricated. The glass-ceramics composites were based in the BNT (BaO-Nd$_2$O$_3$-TiO$_2$), and properties-a sintering and dielectric property-were investigated in its composites according to the $K_2$O-CaO-P$_2$O$_{5}$ system glass frits. The prepared ceramics were sintered at 900∼120$0^{\circ}C$ with the glass frit contents ranging from 10 to 40 wt%. The shrinkage and relative density grew into increasing glass frits and sintering temperature. Sintered composites showed the tendency that the dielectric constant ($\varepsilon$$_{r}$) and quality factor (Q${\times}$f) decreased in increasing glass frits and sintering temperature.