• Clean Technology
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• v.18 no.4
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• pp.390-397
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• 2012

Removal characteristics of lead-contaminated soil at the military shooting range located in the Changwon city were studied experimentally using soil washing process. As a washing solution, hydrogen chloride (HCl) concentrations of 0.001, 0.01, 0.1 and 0.2 N were used, and soil : solution ratios were 1 : 2, 1 : 3, 1 : 4, and 1 : 5. Particle diameter of contaminated soil of 4-0.075 mm, and washing period of 5, 10, 15, 20, 30, 60, and 120 min were used as operating parameters. The optimum concentration of HCl solution was 0.1 N (56.3% of Pb removal efficiency) with 15 minutes operation period in views of economics, and the optimum soil : solution ratio was determined as 1 g : 3 mL for 69.7% of Pb removal efficiency with 0.1 N HCl and 15 minutes washing period. As washing period increased, removal efficiency was increased until 20 min of the removal efficiency of 75.3%, and then almost stable. Pb removal efficiency in soil particle diameters of 0.075 mm or more was ranged from 77.0% to 82.0%, but it was decreased to 52.8% in diameter of less than 0.075 mm. Therefore, the optimum cut-off size of the soil particle diameter was found less than 0.075 mm. Combined HCl solution and ultrasonic washing method showed better removal efficiency compared to only water or HCl washing method for particle sizes above 0.075 mm.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.103-109
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• 2015

In this study, we quantitatively analyzed the data by measuring the radiation shielding rate and uniformity in order to evaluate the performance of an Apron. In addition, storage conditions were also evaluated. The uniformity measurement was performed by evaluating the Apron DICOM images using a PACS program. The experiment was intended for 51 Aprons being used in three hospitals in the Daejeon area. The radiation shielding rate and uniformity were measured per lead equivalent for 0.25 mmPb, 0.35 mmPb, and 0.5 mmPb. As a result, the higher lead equivalents were, the greater differences in the non-uniformity between the top part and the bottom part became (p=0.020). In all hospitals, regarding the non-uniformity of four places in Aprons, all showed statistically significant differences (p<0.01). The average value of the transmitted radiation dose showed less difference (p=0.005) in the bottom right than in the upper right but was statistically significant. There have been no marks of manufacturing date or the date of purchase in the Apron.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1853-1855
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• 2005

본 논문에서는 카메라폰용 광학줌(Optical zooming)과 자동초점조절장치(Auto Focusing, AF)에 쓰일 초음파모터를 제작하였다. 초음파모터의 제작 및 시뮬레이션은 유한요소해석 프로그램인 ATILA 5.2.1(Magsoft)를 사용하여 디자인설계에 따른 구동특성을 고찰하였고 세자된 초음파모터는 한쪽 면이 없는 사자형의 탄성체를 제작하였으며 탄성체의 양쪽 다리에 각각 압전체를 부착하였다. 또한 압전세라믹의 조성은 $0.9Pb(Zr_{0.51}Ti_{0.49})O_3$-$0.1Pb(Mn_{1/3}Nb_{1/3}Sb_{1/3})O_3$의 조성으로 설계하였고 시편의 제조는 7-layer로 적층하였다. 제작된 압전세라믹의 치수는 $6*2*0.35mm^3$ (길이*폭*두께)로 제작하였다. 또한 탄성체의 외형치수는 $10*10*2mm^3$ 제작하였으며 두께를 각각 0.3[mm], 0.5[mm], 0.8[mm]으로 변화시키며 제작하였다. 두께가 0.8[mm]인 경우 공진주파수 60.5[kHz]를 나타내었으며 초음파모터의 압전세라믹에 인가전압이 증가함에 따라 회전속도와 모터에 흐르는 전류는 증가하였다. 인가전압이 40[Vpp], 공진주파수는 60.5[kHz]일때 무게추를 달고 그때의 토크 및 효율을 측정하였다. 회전 속도는 토크가 증가함에 따라 거의 선형적으로 감소하였으며 효율은 토크에 따라 증가하다가 토크가 약 20(mNmm)일 때 약 28[%]로 최대치를 나타내었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.330-330
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• 2008

$Fe_2O_3$ added Pb$(Ni_{1/3}Nb_{2/3})O_3-PbTiO_3-PbZrO_3 $ (PNN-PT-PZ) ceramics were produced in order to use them as a bimoph acturator for energy harvesting. Especially, the 0.25 wt% $Fe_2O_3$ added 0.4PNN-0.357PT-0.243PZ, having the composition of morphotropic phase boundary, showed good piezoelectric properties of $d_{33}$ of 810 pC/N, $k_p$ of 77% and $Q_m$ of 55 along with a high Curie temperature of $210^{\circ}C$. A bimorph actuator, composed of the two piezoelectric layers bonded together with a phosphorous bronze layer as a central metallic electrode, was successfully fabricated. The bimorph actuator, vibrated with a 1.3 mm amplitude at 68 Hz, produced high electric power of approximately 60 mW.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.2
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• pp.39-43
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• 2002

The eutectic solder Sn-37Pb and the lead free solder alloys with the compositions of Sn-0.7Cu, Sn-3.5Ag, Sn-3.5Ag-0.75Cu, Sn-2.0Ag-0.7Cu-3.0Bi were applied to the 48 BGA packages, and then it was discussed for the shear strength at the solder joints as the hardness and the composition of the small solder ball. As a result of experiments, the high degree of hardness with the displacement of 0.043 mm was obtained in Sn-2.0Ag-0.7Cu-3.0Bi. The shear strength of the lead free solder was higher than that of Sn-37Pb solder, and it can be obtained the maximum value of about 52% in Sn-2.0Ag-0.7Cu-3.0Bi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.716-723
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• 1993

This study was carried out to estimate intake level of Pb, Fe, Cu in rural area of Korea(12 males and 18 females). Analyses for the nutritional status of the record, duplicated diet collections, 24-hour urine collections, and venous blood sampling before measuring of blood pressure. The mean age and blood pressure of the subjects were 45.8$\pm$11.1years and 117.5$\pm$22.2/80.8$\pm$15.6mmHe in males, and 41.9$\pm$11.0years, 110.0$\pm$ 11.9/73.9$\pm$8.5mmHg in females, respectively. In respect to both males and females, mean BMI were 22.0$\pm$2.3, 23.1$\pm$3.0, mean Rohrer index were 131.8$\pm$14.8, 142.4$\pm$20.2 and mean skinfold thickness were 12.4$\pm$5.9mm, 25.3$\pm$7.4mm, respectively. The daily mean intakes of Pb, Fe, and Cu estimated for 3 days were 277.2$\pm$111.2$\mu\textrm{g}$/day, 12.7$\mu\textrm{g}$ 7.6mg/day, and 3.0$\pm$1.4mg/day in males and 192.0$\pm$72.4$\mu\textrm{g}$/day, 13.3$\pm$5.8mg/day, and 3.7 $\pm$1.7mg/day in females, respectively. The mean concentrations of serum Pb, Fe, Cu were 11.0$\pm$2.0$\mu\textrm{g}$/dl, 131.1$\pm$42.6$\mu\textrm{g}$/dl, 120.3$\pm$25.7$\mu\textrm{g}$/dl in males and 9.0$\pm$1.2$\mu\textrm{g}$/dl, 112.2$\pm$ 35.9$\mu\textrm{g}$/dl, 117.3$\pm$17.9$\mu\textrm{g}$/dl in females, respectively. The mean levels of Hb and Hct were 15.1$\pm$1.1g/dl, 45.2$\pm$3.3% in males and 13.1$\pm$0.8g/dl, 39.8$\pm$2.6% in females, respectively. The 24-hour urinary excretions of Pb, Fe, Cu were 35.5$\pm$10.0$\mu\textrm{g}$/day, 0.16$\pm$0.12mg/day, 60.12$\pm$0.02$\mu\textrm{g}$/day in males, and 25.3$\pm$11.0$\mu\textrm{g}$/day, 0.24$\pm$0.20mg/day, 70.07$\pm$0.03$\mu\textrm{g}$/day in females, respectively. In conclusion, the Pb intake in self selected diet of this subjects was not in the level that antagonized to Fe and Cu metabolism seriously.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.719-720
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• 2009

We suggest a new approach to lower the operating voltage of plasma display devices using a piezoelectric transformer (PT). $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ (PMNT) was used as a piezoelectric material. The Rosen-type PT, with a compact size of 10 mm ${\times}$ 20 mm ${\times}$ 0.3 mm, was fabricated on a glass substrate. The fabricated PT was operated as a half-wave vibration mode at around 80~90 kHz. The maximum voltage step-up ratio was 3 at 87.8 kHz when the input voltage was 10.32 V (peak-to-peak).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.423-426
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• 2000

The 3-D $31.5$\times$31.5$\times$2.5mm$^3$model of contour vibration mode piezoelectric transformer with Pb($Ni_{1/2}$$W_{1/2}$)$O_3$-Pb(Zr,Ti)$O_3$ ceramics was simulated by ANSYS according to the dot size 17, 18, 19, 20, 21 $mm\phi$ and analyzed the results. The mechanical quality factor of the 3-D model was decreased with the dot size and increased as 2605 at 20 $mm\phi$ and after then decreased again. The output voltage of that sample was 74123 [V] and the maximum stress of the dot electrode at that sample was 288[$10^7$N/$m^2$] and the maximum displacement of the ring electrode at that sample was 128 [$\mu\textrm{m}$].

• Resources Recycling
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• v.3 no.1
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• pp.38-43
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• 1994

The separation of valuable metals from IC chip scrap generated by domestic electronic company was carried out using the mechanical beneficiation such as shredding, crushing, screening and magnetic separation. The distribution of metals in various sizes of crushed IC chip scrap was investigated and metals present in crushed products was separated with the magnetic separator. The particle size distribution of crushed IC chip scrap was 7.5% for +3mm, 17.0% for 3~1mm and 75.5% for -1mm. The weight loss of crushed IC chip scrap was 18% when roasted at $700^{\circ}C$. The content of metals was 96% for +3~1mm, 13% for 1~0.595mm, 3.7% for 0.95~0.5. Au of 99% was present in -1mm crushed IC chip scrap. Ni, Fe, Cu, Sn and Pb were separated from crushed IC chip scrap by the magnetic separator under 700 and 2, 500 Gauss.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.1-8
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• 1996

High-sensitive pyroelectric infrared sensors have been fabricated with La-modified $PbTiO_{3}$(PLT) thin plates. The PLT thin plates have the composition of $(Pb_{0.9}La_{0.1}Ti_{0.75}O_{3})_{0.75}(PbO)_{0.25}$. Thickness of the thin plates is $100\;{\mu}m$. Top side electrodes exposed to IR are vacuum evaporated Ni-Cr, and bottom side electrodes are Ag. Each one takes the area of $1{\times}2\;mm^{2}$. The thin plates have a large resistivity of $6.41{\times}10^{10}{\Omega}{\cdot}cm$ and a relative dielectric constant of 341. They have a high figure of merit of $4.0{\times}10^{-11}\;Ccm/J$ due to its high pyroelectric coefficient of $4.45{\times}10^{-8}\;C/cm^{2}K$. The sensors show such a large voltage responsivity as 2501 V/W. That they can find practical applications like the pyroelectric infrared detectors.