• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.231-239
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• 2013

Purpose: To design and fabricate the auto pattern maker for the development. Methods: we got the necessary data, needed in design, by using CAD. Based on the these data, we fabricated the trial product for the development of the auto pattern maker. Results: The auto pattern maker were composed with combinations of many elements; pattern making assembly, control panel, frame attachment and prober unit. The pattern making assembly was comprised of the cutter, the pattern holder, pattern remover and silence cover which could minimize the sound during the cutting process. The control panel was designed to be connected and operated with the main printed circuit board. The prober could get the eye shape data by scanning of 1.8 degrees around the groove of the frame through the encoding data according to the address. After starting, scanning was carried out in two passes, i.e. one right-handed and one left-handed. Communication connector could send the eye shape data from auto pattern maker to outer system with the RS232C transmission system. By using the one-way analysis of variance, we got the error rate of cut pattern size for ${\Phi}22mm$, ${\Phi}55mm$ and ${\Phi}62mm$. Because F-value was 0.510 and p-value was 0.601, no statistically significant differences were found. Also, the mean cutting error of the auto pattern maker was 0.0274 mm. Conclusions: we could succeed in making the trial product by applying it to the development of the auto pattern maker. The role of this auto pattern maker is to find a exact required size of lens to fit the frame by measuring the frame. The acquired data are transferred to outer system for grinding and finishing with patternless process. Also, the trial product can produce pattern to fit the frame. Therefore, it was confidently expected that the optometrists could handily produce pattern to fit the frame with this trial product and dispense the ophthalmic lens because of its efficiency and convenience compared to the past.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.135-147
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• 2015

Recent underground common utility tunnels are underground facilities for jointly accommodating more than 2 kinds of air-conditioning and heating facilities, vacuum dust collector, information processing cables as well as electricity, telecommunications, waterworks, city gas, sewerage system required when citizens live their daily lives and facilities responsible for the central function of the country but it is difficult to cope with fire accidents quickly and hard to enter into common utility tunnels to extinguish a fire due to toxic gases and smoke generated when various cables are burnt. Thus, in the event of a fire, not only the nerve center of the country is paralyzed such as significant property damage and loss of communication etc. but citizen inconveniences are caused. Therefore, noticing that most fires break out by a short circuit due to electrical works and degradation contact due to combustible cables as the main causes of fires in domestic and foreign common utility tunnels fire cases that have occurred so far, the purpose of this paper is to scientifically analyze the behavior of a fire by producing the model of actual common utility tunnels and reproducing the fire. A fire experiment was conducted in a state that line type fixed temperature detector, fire door, connection deluge set and ventilation equipment are installed in underground common utility tunnels and transmission power distribution cables are coated with fire proof paints in a certain section and heating pipes are fire proof covered. As a result, in the case of Type II, the maximum temperature was measured as $932^{\circ}C$ and line type fixed temperature detector displayed the fire location exactly in the receiver at a constant temperature. And transmission power distribution cables painted with fire proof paints in a certain section, the case of Type III, were found not to be fire resistant and fire proof covered heating pipes to be fire resistant for about 30 minutes. Also, fire simulation was carried out by entering fire load during a real fire test and as a result, the maximum temperature is $943^{\circ}C$, almost identical with $932^{\circ}C$ during a real fire test. Therefore, it is considered that fire behaviour can be predicted by conducting fire simulation only with common utility tunnels fire load and result values of heat release rate, height of the smoke layer, concentration of O2, CO, CO2 etc. obtained by simulation are determined to be applied as the values during a real fire experiment. In the future, it is expected that more reliable information on domestic underground common utility tunnels fire accidents can be provided and it will contribute to construction and maintenance repair effectively and systematically by analyzing and accumulating experimental data on domestic underground common utility tunnels fire accidents built in this study and fire cases continuously every year and complementing laws and regulations and administration manuals etc.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.518-524
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• 2003

Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit was made for lead inhalation toxicology study and 2730ppm lead nebulizing solution was used to generate lead aerosol. After modification of source and inlet temperatures, the results of particle size analysis for lead aerosol were as following. The highest particle counting for source temperature 20℃ was 39933.66 in inlet temperature 100℃ and particle diameter 0.75tLm. The highest particle counting for source temperature 50℃ was 39992.71 in inlet temperature 250℃ and particle diameter 0.75μm. The highest particle counting for source temperature 70℃ was 37569.55 in inlet temperature 50℃ and particle diameter 0.75μm. The ranges of geometric mean diameter(GMD) were 0.754-0.784μm for source temperature 2℃, 0.758-0.852μm for source temperature 50℃, and 0.869-1.060μm for source temperature 70℃. The smallest GMD was 0.754μm in source temperature 20℃ and inlet temperature 20℃, and the largest GMD was 1.060μm in source temperature 70℃ and inlet temperature 250℃. The ranges of geometric standard deviation(GSD) were 1.730-1.782 for source temperature 20℃, 1.734-1.894 for source temperature 50℃, and 1.921-2.148 for source temperature 70℃. The lowest GSD was 1.730 in source temperature 20℃ and inlet temperature 20℃, and the highest GSD was 2.148 in source temperature 70℃ and inlet temperature 250℃. Lead aerosol generated in this study was polydisperse. The ranges of mass median diameter(MMD) were 1.856-2.133μm for source temperature 20℃, 1.877-2.894μm for source temperature 50℃, and 3.120-6.109μm for source temperature 70℃. The smallest MMD was 1.856μm in source temperature 20℃ and inlet temperature 20℃, and the largest MMD was 6.109μm in source temperature 70℃ and inlet temperature 250℃. Slight increases for GMD, GSD, and MMD values were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but inlet temperature 20℃ and 50℃ for source temperature 70℃ were conformed EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3μm. In this study, source temperature 20℃ and 50℃ with inlet temperature from 20℃ to 250℃ were conformed to the EPA guidance, but none for source temperature 70℃.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.11-18
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• 2004

Background: We tested the effect of indomethacine and total spinal anesthesia on the improvement of placental flow during cardiopulmonary bypass on fetal lamb. Material and Method: Twenty fetuses at 120 to 150 days of gestation were subjected to bypass via trans-sternal approach with a 12 G pulmonary arterial cannula and 14 to 18 F venous cannula for 30 minutes. All ewes received general anesthesia with ketamine. In all the fetuses, no anesthetic agents were used except muscle relaxant. Ten served as a control group in which placenta was worked as an oxygenator during bypass (Control group). The remainder worked as an experimental group in which pretreatment with indomethacine and total spinal anesthesia was performed before bypass with the same extracorporeal circulation technique as control group (Experimental group). Observations were made every 10 minutes during a 30-minute bypass and 30-minute post bypass period. Result: Weights of the fetuses ranged from 2.2 to 5.2 kg. In Control group, means of arterial pressure decreased from 44.7 to 14.4 mmHg and means of Pa$CO_2$ increased from 61.9 to 129.6 mmHg at each time points during bypass. Flow rate was suboptimal (74.3 to 97.0 $m\ell$/kg/min) during bypass. All hearts fibrillated immediately after the discontinuation of bypass. On the contrary, in Experimental group, means of arterial pressure reamined higher (45.8 to 30 mmHg) during bypass (p<0.05). Means of Pa$CO_2$ were less ranging from 59.8 to 79.4 mmHg during bypass (P<0.05). Flow rates were higher (78.8 to 120.2 $m\ell$/kg/min) during bypass (p<0.05). There were slower deterioration of cardiac function after cessation of bypass. Conclusion: In this study, we demonstrated that the placental flow was increased during fetal cardiopulmonary bypass in the group pretreated with indomethacine and total spinal anesthesia. However, further studies with modifications of the bypass including a creation of more concise bypass circuit, and a use of axial pump are mandatory for the clinical application.

• Journal of Chest Surgery
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• v.36 no.8
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• pp.559-565
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• 2003

By improving the flow pattern in Fontan circuit, total cavopulmonary connection (TCPC) could result in a better outcome than atriopulmonary connection Fontan operation. For the patients with impaired hemodynamics after atriopulmonary Fontan connection, conversion to TCPC can be expected to bring hemodynamic and functional improvement. We studied the results of the revision of the previous Fontan connection to TCPC in patients with failed Fontan circulation. Material and method: From October1979 to June 2002, eight patients who had failed Fontan circulation, underwent revision of previous Fontan operation to TCPC at Yonsei University Hospital. Intracardiac anomalies of the patients were tricuspid atresia (n=4) and other functional single ventricles (n=4). Mean age at TCPC conversion was 14.0$\pm$7.0 years (range, 4.6~26.2 years) and median interval between initial Fontan operation and TCPC was 7.5 years (range, 2.4~14.3 years). All patients had various degree of symptoms and signs of right heart failure. NYHA functional class was 111 or IV in six patients. Paroxysmal atrial fibrillation (n:f), cyanosis (n=2), intraatrial thrombi (n=2), and protein losing enteropathy (PLE) (n=3) were also combined. The previous Fontan operation was revised to extracardiac conduit placement (n=7) and intraatrial lateral tunnel (n=1). Result: There was no operative death. Major morbidities included deep sternal infection (n=1), prolonged pleural effusion over two weeks (n=1), and temporary junctional lachyarrhythrnia (n=1). Postoperative central venous Pressure was lower than the preoperative value (17.9$\pm$3.5 vs. 14.9$\pm$1.0, p=0.049). Follow-up was complete in all patients and extended to 50,1 months (mean, 30.3$\pm$ 12.8 months). There was no late death. All patients were in NYHA class 1 or 11. Paroxysmal supraventricular tachycardia developed in a patient who underwent conversion to intraatrial lateral tunnel procedure, PLE was recurred in two patients among three patients who had had PLE before the convertsion. There was no newly developed PLE. Conclusion: Hemodynamic and functional improvement could be expected for the patients with Fontan circulatory failure after atriopulmonary connection by revision of their previous circulation to TCPC. The conversion could be performed with low risk of morbidity and mortality.

• Journal of Chest Surgery
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• v.29 no.6
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• pp.639-645
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• 1996

A 14-year-old male patient with previous surgical repair of tetralogy of Fallot was admitted with hemodynamically significant ventricular tachycardia (VT). On preoperative electrophysiologic study (EPS), the morphology of documented VT was RBBB of vertical axis with 320 msec cycle length. The endocardial mapping during VT delineated the origin of VT at right ventricular outflow tract (RVOT), where the patch was attached. The clinical VT had a clockwise reentry circuit around the patch with the earliest activation at the same site seen during the preoperative EPS. The previously placed right ventricular outflow patch and fibrous tissue were removed. During a postoperative EPS, it was no longer possible to induce the VT. Ventricular tachycardia following repair of tetralogy of Fallot seen in this patient was caused by a macro-reentry around the right ventricular outflow patch. We were able to ablate the VT with the aid of a detailed mapping of its epicardial activation sequence.

• The Korean Journal of Nuclear Medicine
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• v.32 no.4
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• pp.365-373
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• 1998

Purpose: The conventional gamma camera is not ideal for scintimammography because of its large detector size (${\sim}500mm$ in width) causing high cost and low image quality. We are developing a small gamma camera dedicated for breast imaging. Materials and Methods: The small gamma camera system consists of a NaI (T1) crystal ($60 mm{\times}60 mm{\times}6 mm$) coupled with a Hamamatsu R3941 Position Sensitive Photomultiplier Tube (PSPMT), a resister chain circuit, preamplifiers, nuclear instrument modules, an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a standard resistive charge division which multiplexes the 34 cross wire anode channels into 4 signals ($X^+,\;X^-,\;Y^+,\;Y^-$). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated ana digitized via triggering signal and used to localize the position of an event by applying the Anger logic. Results: The intrinsic sensitivity of the system was approximately 8,000 counts/sec/${\mu}Ci$. High quality flood and hole mask images were obtained. Breast phantom containing $2{\sim}7 mm$ diameter spheres was successfully imaged with a parallel hole collimator The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We have succesfully developed a small gamma camera using NaI(T1)-PSPMT and nuclear Instrument modules. The small gamma camera developed in this study might improve the diagnostic accuracy of scintimammography by optimally imaging the breast.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.93-98
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• 2017

This experiment investigated characteristic changes in a $Cu_2ZnSnS_4$(CZTS) solar cell by applying a $Zn(O_x,S_{1-x})$ butter layer with various compositions on the upper side of the absorber layer. Among the four single layers such as $Zn(O_{0.76},S_{0.24})$, $Zn(O_{0.56},S_{0.44})$, $Zn(O_{0.33},S_{0.67})$, and $Zn(O_{0.17},S_{0.83})$, the $Zn(O_{0.76},S_{0.24})$ buffer layer was applied to the device due to its bandgap structure for suppressing electron-hole recombination. In the application of the $Zn(O_{0.76},S_{0.24})$ buffer layer to the device, the buffer layer in the device showed the composition of $Zn(O_{0.7},S_{0.3})$ because S diffused into the buffer layer from the absorber layer. The $Zn(O_{0.7},S_{0.3})$ buffer layer, having a lower energy level ($E_V$) than a CdS buffer layer, improved the $J_{SC}$ and $V_{OC}$ characteristics of the CZTS solar cell because the $Zn(O_{0.7},S_{0.3})$ buffer layer effectively suppressed electron-hole recombination. A substitution of the CdS buffer layer by the $Zn(O_{0.7},S_{0.3})$ buffer layer improved the efficiency of the CZTS solar cell from 2.75% to 4.86%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1288-1298
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• 2002

To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

• Clean Technology
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• v.17 no.4
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• pp.306-313
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• 2011

Flux or solder is used in soldering process for manufacturing electronic parts such as printed circuit boards (PCB). After soldering process, residual flux and solder paste on the parts should be removed since their residuals could cause performance degradation or failure of parts due to their corrosion and electric leakage. Ozone depletion substances such as 1,1,1- trichloroethane (TCE) and HCFC-141b have widely been using for removal of residual flux and solder paste after soldering process In manufacturing of electronic parts until now. In this study, non-aqueous cleaning agents without flash point were developed and applied to industrial field for replacement of cleaning agents with ozone depletion. In order to develop non-aqueous cleaning agents without ethers, esters, fluoride- type solvents. And their physical properties and cleaning abilities were evaluated, and they were applied to industrial fields for cleaning of flux and solder on the PCB. And vacuum distillation apparatus were operated to determine their operating conditions and recycling yields for recycling of used cleaning agents formulated in this study. As a result of physical properties measurement of our formulated cleaning agents, they were expected to have good wetting and penetrating power since their surface tensions were relatively low as 18.0~20.4 dyne/$cm^2$ and their wetting indices are relatively large. And some cleaning agents holding fluoride-type solvents as their components did not have any flash point and they seemed to be safe in their handling and storage. The cleaning experimental results showed that some cleaning agents were better in their cleaning of flux and solder paste than 1,1,1-TCE and HCFC-141b. And industrial application results of the formulated cleaning agents for cleaning PCB indicated that they can be applicable to industry due to their good cleaning capability in comparison with HCFC-141b. The recycling experiments of the used formulated cleaning agents through a vacuum distillation apparatus also showed that their 91.9~97.5% could be recycled with its proper operating conditions.