• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.254-255
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• 2005

In this paper, we investigated electrical characteristics of the X-ray detector of mercuric iodide (HgI2) film fabricated by PIB(Particle-in-Binder) Method on ITO substrates 17cm$\times$20cm in size with thicknesses ranging from approximately 200${\mu}m$ to 240${\mu}m$. In the present study, using I-V measurements, their electrical properties such as leakage current, X-ray sensitivity, and signal-to-noise ratio (SNR),were investigated. The results of our study can be useful in the future design and optimization of direct active-matrix flat-panel detectors (AMFPD) for various digital X-ray imaging modalities.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.355-361
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• 1991

The separative preconcentration of trace mercury[Hg(II)] in a water sample was studied by a coprecipitation flotation technique. The trace Hg(II) was precipitated together with Ce(OH)$_3$ by adding 3.0 ml of 0.1M Ce$^{3+}$ solution to 1,000 ml of water sample and adjusting pH to 11.0 with 1.0M NaOH solution. The hydrophobic precipitate[Ce(OH)$_3$-Hg(OH)$_2$], which was formed by adding 2.0 ml of 0.1${\%}$ ethanolic sodium oleate solution, were floated on the surface with an aid of tiny nitrogen gas bubbles. The floated materials were quatitatively collected in a suction flask and dissolved with 5.0 ml of 2.0M HNO$_3$. The solution was marked to 25.00 ml with a deionized water. The content of Hg(II) was determined by cold vapor atomic absorption spectrophotometry. Any interferences of concomitants such as Ag$^+$, Br$^-$, I$^- $, etc. were not observed on the whole procedure. The analytical result showed that Hg(II) found in the wastewater of Seochang Campus, Korea University was 1.98 ng/ml with the relative standard deviation of 3.6${\%}$. And recoveries of Hg(II) in the wastewater into which 1.0 ng/ml and 2.0 ng/ml were added were 95${\%}$ and 91${\%}$, respectively. From such results, this procedure could be concluded to be tolerably accurate and reproducible for the determination of trace mercury in a water sample.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1022-1030
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• 1998

Background : In volume-controlled ventilation, the use of inspiratory pause increases the inspiratory time and thus increases mean airway pressure and improves ventilation. But under the same I : E ratio, the effects of inspiratory pause on mean airway pressure and gas exchange are not certain. Moreover, the effects may be different according to the resistance of respiratory system. So we studied the effects of inspiratory pause on airway pressure and gas exchange under the same I : E ratio in volume-controlled ventilation. Methods: Airway pressure and arterial blood gases were evaluated in 12 patients under volume-controlled mechanical ventilation with and without inspiratory pause time 5%. The I : E ratio of 1 : 3, $FiO_2$, tidal volume, respiratory rate, and PEEP were kept constant. Results: $PaCO_2$ with inspiratory pause was lower than without inspiratory pause ($38.6{\pm}7.4$ mmHg vs. $41.0{\pm}7.7$ mmHg. p<0.01). P(A-a)$O_2$ was not different between ventilation with and without inspiratory pause $185.3{\pm}86.5$ mmHg vs. $184.9{\pm}84.9$ mmHg, p=0.766). Mean airway pressure with inspiratory pause was higher than without inspiratory pause ($9.7{\pm}4.0\;cmH_2O$ vs. $8.8{\pm}4.0\;cmH_2O$, p<0.01). The resistance of respiratory system inversely correlated with the pressure difference between plateau pressure with pause and peak inspiratory pressure without pause (r=-0.777, p<0.l), but positively correlated with the pressure difference between peak inspiratory pressure with pause and peak inspiratory pressure without pause (r=0.811, p<0.01). Thus the amount of increase in mean airway pressure with pause positively correlated with the resistance of respiratory system (r=0.681, p<0.05). However, the change of mean airway pressure did not correlated with the change of $PaCO_2$. Conclusion: In volume-controlled ventilation under the same I : E ratio of 1 : 3, inspiratory pause time of 5% increases mean airway pressure and improves ventilation. Although the higher resistance of respiratory system, the more increased mean airway pressure, the increase in mean airway pressure did not correlated with the change in $PaCO_2$.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.81-84
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• 2013

The use of the dosimetry have been increasingly recognized as high radiation energy and radiation treatment planning(RTP) have rapidly developed in radiotherapy. There are many types of detectors for the dosimetry such as ionization chamber, film, TLD, diode, and etc. Among such detectors, the diode detector uses a photoconductor materials that generate electrical signals by the incident radiation energy. Though many research groups are recently interested in such materials, there is few experimental results except for silicon in the radiation therapy field. In this study, the feasibility of photoconductor materials was verified as a dosimeter through the evaluation of response properties at a high radiation energy. For the fabricated detectors based on $HgI_2$ and $PbI_2$, reproducibility, linearity, and pulse-rate response were analyzed. Such evaluations are essential factors for the use of dosimeter. From results, linearity and reproducibility of the fabricated $HgI_2$ detector indicated about 7% error. The fabricated $PbI_2$ detector showed 1.7% error in linearity, and 12.2% error in reproducibility.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.257-263
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• 2022

In intracavitary radiotherapy, it is essential to verify the correct location of radiation source among quality control items because an incorrect location will irradiate an unnecessary dose to normal tissues. As a basic study of digital line dosimeters, this study fabricated a unit cell dosimeter based on polycrystalline mercury (II) iodide (HgI₂) and compared its performance with a diode. The study result showed that for reproducibility, the relative standard deviation (RSD) was 1.21%, satisfying the RSD evaluation criterion of within 1.5%. Considering linearity, the coefficient of determination R² showed an excellent result of 0.9997. Regarding the evaluation of distance dependence, it showed a similar trend in general with a difference of 0.035 cm for intensity 50% when compared with the inverse square value. This study suggests the applicability of a digital dosimeter for brachytherapy quality control by evaluating the performance of the HgI₂ dosimeter. This study on dosimeter for candidate photoconductor materials can be used as basic data in all areas using radiation.

• Journal of Chest Surgery
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• v.30 no.3
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• pp.253-253
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• 1997

Hypothermia during lung preservation decreases metabolic processes. After the rabbit lung was flushed with modified Euro-Collins solution, heart-lung block was harvested and the left lung was assessed after ligation of the right pulmonary artery and right main-stem bronchus. Heart-lung block was immersed in the same solution for 6 hours. The modified Euro-Collins solution and storage temperature of group 1(10 cases) was 4t, roup 2(10 cases) was l0℃. On completion of the storage period, the left lung was ventilated and reperfused with blood u:high used a cross-circulating paracorporeal rabbit as a "biologic deoxygenator" for 60 minutes. Pulmonary artery pressure, airway pressure, difference in oxygen tension between mow and outflow perfusate and degree of pulmonary edema were assessed at 10-minute intervals while the left lung was ventilated at 0.8 of the inspired oxygen fraction. The mean pulmonary venous oxygen tensions at 10 and 60 minutes after reperfusion were 209.52±42.46 and 103.48± 15.96 mmHg in group I versus 247.78±36.19 and 147.91 ± 11.07 mmHg in group II(p=0.049, (0.0001). The mean alveolar-arterial oxygen differences at 20 and 60 minutes after reperfusion were 357. 95± 12.84 and 437.31 14.26 mmHg in group I versus 310.88±3).47 and )90.93± 15.86 mmHg in group II (p=0.0092, (0.0001). The mean pulmonary arterial pressures at 10 and 60 minutes after reperfusion were 40.56± 18.66 and 87. 2± 17.22 mmHg in group I versus 31.22±6.84 and 65.78± 11.02 mmHg in group rl (p : 0.048, 0.0062). The mean pulmonary vascular resistances at 10 and 60 minutes after reperfusion were 2.69±0.85 and 4.36±0.86 mmHg/ml/min in group I versus 1.99±0.39 and 3.29±0.55 mmHg/ml/min in group II(p : 0.0323, 0.0062). There were no difference between groups in peak airway pressure, lung compliance and degree of pulmonary edema. In conclusion that preservation of lung at l0℃ was superior to preservation at 4℃.

• Journal of the Korean Society of Radiology
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• v.3 no.2
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• pp.11-16
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• 2009

Mercury Iodide as good sensitivity at radiation and has an easy peculiarity that operates at low voltage for other photoconductors(a-Se, a-Si, Ge, etc) Based on this characteristic, we studied about an efficiency of the digital x-ray detector in acccordance with the thickness of photoconductor. To solve the problem that is difficult to make a large area film using PVD(Physical Vapor Deposition)method, we used a PIB(Particle In Binder)method. To make a binder paste, we used a PVB(Polyvinylbutyral) as a binder and a DGME(Diethylene Glycol Monobutyl Ether), DGMEA(Diethylene Glycol Monobutyl Ether Acetate) as a solvent. Using this binder paste, we made a polycrystal mercury iodide film that has an each thickness. To evaluate the electrical properties of this films, we measured a darkcurrent, sensitivity and SNR(Signal to Noise Ratio). Mercury iodide film of the 200um thickness has good electrical properties as a result of the measurement. From this result there is a good chance that replace the existing a-Se(Amnorphous seleinum; a-se) with the mercury iodide.

• Journal of Korean Biological Nursing Science
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• v.11 no.2
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• pp.99-104
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• 2009

Purpose: An animal model of pressure ulcers was experimentally-induced with the use of greater trochanter of rats. Methods: Twelve male Sprague-Dawley rats were used in this study and they were randomly divided into 4 groups: Group I (n=3, 120 mmHg, 2 hr), Group II (n=3, 120 mmHg, 3 hr), Group III (n=3, 140 mmHg, 3 hr) and Group IV (n=3, 140 mmHg, 4 hr). The rats were anesthetized with 100 mg/kg of ketamine. The pressure ulcers were induced by using a personally-designed pressing apparatus. After 5 days, the wounds were photographed and excised. Results: After 5 days of induced pressure ulcers, it was observed that Group I and Group II responded with Grade I and Grade II, respectively, while Group III and Group IV responded with Grade III. Conclusion: According to the result of this study, it can be concluded that the pressure ulcers were induced the characteristic grades of pressure ulcer classification by adjusting the degree and the duration of compression.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.11
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• pp.969-974
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• 2003

HgGa$_2$S$_4$ single crystals were grown by the chemical transport reaction method. The HgGa$_2$S$_4$ single crystal crystallized into a defect chalcopyrite structure (I 4). The lattice constants of the single crystal were found to be a = 5.635 $\AA$ and c = 10.473 $\AA$. The direct and indirect optical energy gaps were found to be 2.84eV and 2.78eV, respectively. Photoluminescence peaks of HgGa$_2$S$_4$ single crystal were observed at 2.37 eV, 2.18 eV, and 1.81 eV. In the single crystal, the donor level of 0.25 eV, the acceptor levels of 0.97 eV and 0.41 eV were obtained by TSC, PICTS, and absorption measurements. The photoluminescence peaks were analyzed to relate to the indirect conduction band, the donor level, and the acceptor levels.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.258-258
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• 2005