• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4013-4018
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• 2014

A 0.45 $cm^2$ DSSC device with a glass/FTO/blocking layer/$TiO_2$/N719(dye)/electrolyte/50 nm-Pt/50 nm-Au/FTO/glass was prepared to examine the stability of the Au/Pt bilayered counter electrode (CE) with electrolyte and the energy conversion efficiency (ECE) of dye-sensitized solar cells (DSSCs). For comparison, a 100 nm-thick Pt only CE DSSC was also prepared using the same method. The photovoltaic properties, such as the short circuit current density ($J_{sc}$), open circuit voltage ($V_{oc}$), fill factor (FF), and ECE, were checked using a solar simulator and potentiostat with time after assembling the DSSC. The microstructure of the Au/Pt bilayer was examined by optical microscopy after 0~25 minutes. The ECE of the Pt only CE-employed DSSC was 4.60 %, which did not show time dependence. On the other hand, for the Au/Pt CE DSSC, the ECEs after 0, 5 and 15 minutes were 5.28 %, 3.64 % and 2.09 %, respectively. The corrosion areas of the Au/Pt CE determined by optical microscopy after 0, 5, and 25 minutes were 0, 21.92 and 34.06 %. These results confirmed that the ECE and catalytic activity of Au/Pt CE decreased drastically with time. Therefore, a Au/Pt CE-employed DSSC may be superior to the Pt only CE-employed one immediately after integration of the device, but it would degrade drastically with time.

• Korean Security Journal
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• no.14
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• pp.311-336
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• 2007

This study examines the concepts of counter-act against the Bio-terrorism and the reaction system in advanced countries, thereby to find out reaction system necessary to Korea. Acts on anti-Bio-terrorism is divided to detection stage, protection stage, diagnosis stage and detoxication and neutralization stage according to flow of event occurrence. As for detection stage, Korea is developing it as contact type, while advanced countries are under development of the devices that may detect the terrorism from the remote distance. It is necessary for Korea to develop the remote-distant detection system as well as the contact type of device that may promptly operate. Among the protection gears, the quality of Korea's gas mask is recognized worldwide, but that of other outfits should be improved by applying the state-of-art science technology. The diagnosis device also should be developed to the extent that the dispatched initial action team may make immediate decisions necessary in the field. As the current trends for detoxication materials worldwide require the improvement to new materials harmless to human body and equipment, Korea is also required to acquire those materials. The technology for neutralization means the development of vaccine and antibiotics and it requires the development made by shared efforts worldwide. For this purpose, it is necessary to further develop Korea's medical technology. In addition, the further efforts are required in terms of reaction manual, training model, public communication efforts and preparation for trauma syndrome.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.191-195
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• 2000

This study was undertaken to estimate the exposed dose of the medical personnel during the intracoronary radiotherapy procedure as a part of ongoing SPARE (Seoul National University Hospital Post-Angioplasty Rhenium) trial. Data of thirty-four patients among forty-two irradiated patients participating in this trial due to coronary artery stenosis were retrospectively analyzed. Intracoronary radiotherapy was delivered to the patient immediately after angioplasty ballooning. Prescribed dose was 17 Gy to media of the diseased artery and was delivered with $^{188}Re$ filled balloon catheter. Dosimetry was carried out with GM counter at eight different points. Ten centimeter and forty centimeter from the patient's heart were selected to represent maximum and whole-body exposed dose of the operator, respectively. Median delivered dose was 111.6 mCi with average treatment time of 576 seconds. Average exposed dose rate at 10 cm and 40 cm from the patient's heart were 0.43 mSv/hr and 0.30 mSv/hr, respectively. Average exposed doses per treatment were 0.07 mSv and 0.05 mSv for 10 cm and 40 cm from the patient's heart, respectively. Exposed doses measured are much lower than recommended limit of 50 mSv for radiation workers or 1 mSv for general population in ICRP-60. This study proves that current method of intracoronary radiotherapy incorporated in this trial is very safe regarding radiation protection.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.23-30
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• 2016

In this study, the heat transfer and pressure drop characteristics were evaluated for multi-tube $CO_2$ water heaters with lengths of 4.5 m and 7.5 m. The evaluation was done using the -NTU method, and the results were compared with experimental data. Water flows through the shell side of the water heater, while $CO_2$ flows through 8 inner tubes. The heater uses a counter-current design to maximize the heat transfer efficiency. The energy balance equation describing the flows of $CO_2$ and water for each node is set up using the section-by-section method. The calculated heat transfer rates agree well with the experimental data within ${\pm}5%$ error. The outlet water temperature decreased linearly with the increase of the water flow rate. The calculated heat transfer rates agreed well with the experimental data within ${\pm}3%$ error. The results show that the heat transfer rate increases almost linearly with the increase of water flow rate or $CO_2$ inlet temperature in both the 4.5-m and 7.5-m water heaters, whereas the water outlet temperature linearly decreases with the increase of the water flow rate. The comparison of the $CO_2$ pressure drop between the calculation and experiment results shows good agreement at the high $CO_2$ flow rate within 5 % error, but the value is about 20 % higher in the experimental pressure drop at the low $CO_2$ flow rate.

• Journal of the Korean Society for Heat Treatment
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• v.20 no.2
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• pp.84-93
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• 2007

Microstructural changes during tempering at the temperature range of $300^{\circ}C{\sim}700^{\circ}C$ for the nitrogen-permeated STS 410 and 410L martensitic stainless steels has been investigated. After nitrogen permeation at temperature between 1050 and $1150^{\circ}C$, the surface layer appeared fine $Cr_2N$ of square and rod types in the martensite matrices. Hardness of the nitrogen-permeated surface layer represented 680Hv and 625Hv, respectively, for 410 and 410L steels. It is considered that the fine homogeneously dispersive effect of precipitates by nitrogen caused the increased hardness. Due to the counter current effect of carbon from interior to surface during nitrogen diffusion from surface to interior, the 0.1%C alloyed 410 steel showed the low nitrogen content of 0.025% compared with 0.045% of 410L steel at the distance of $100{\mu}m$ from the surface. Tempering of nitrogen-alloyed 410 and 410L showed the maximum hardness at $450^{\circ}C$. This maximum hardness was considered to be the secondary hardening effect of very fine carbide and nitride. The decrease in hardness at $700^{\circ}C$ was the softening effect of the matrix due to the precipitation of many needle-shaped $Cr_2N$ for 410 steel and the precipitation of coarse nitride of $Cr_2N$ in line with the spherical precipitates with directionality for 410L steel. For 410 steel, the corrosion resistance of nitrogen permeated surface in the solution of 1 N $H_2SO_4$ were nearly unchanged, however the superior corrosion resistance was obtained for nitrogen permeated 410L steel compared to the solution annealed condition.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.213-220
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• 1983

Pulmonary function is the determinant of blood gas tension. However, Acid-Base disturbances can also alter partial pressures of oxygen and carbon dioxide in arterial blood. During respiratory acidosis $PO_2$ will be lowered and reverse changes will be produced during respiratory alkalosis. On the other hand, in metabolic acidosis $PO_2$ will be elevated and $PCO_2$ will be lowered by the respiratory compensation, and reverse response will be induced in metabolic alkalosis. Urinary gas tension has many influencing factors than arterial blood and difficult to estimate the tendency of its alterations. Urinary $PO_2$ and $PCO_2$ are not always identical level as venous blood. It is to be altered by blood gas tension, flow rate of urine, metabolic rate of kidney, and Acid-Base status of blood. Particularly countercurrent exchange of oxygen and carbon dioxide in the renal medulla will make larger alteration of gas tension than venous blood. After induction of Acid-Base disturbances [disturbances] arterial and urinary $PCO_2$, $PO_2$, urinary volume, and osmolarity were determined in dogs, and the relationships between arterial and urinary $PCO_2$ , $PO_2$ Acid-Base disturbances, urinary volume, and osmolarity were investigated. 1. During the acute Metabolic and Respiratory disturbances urinary pH did not respond on respiratory origin. However, there were immediate urinary response in pH on metabolic origin. 2. Urinary $PO_2$, $PCO_2$, did not always follow arterial or venous gas tension and Acid-Base disturbance. Urinary $PCO_2$, correlate well with the urinary volume. The larger the urinary volume, $PCO_2$ lowered to the venous level. The smaller the urinary volume, urinary $PCO_2$ tends to be higher. However urinary $PO_2$ did not have any particular correlation with urinary volume. 3. Correlation between urinary $PCO_2$ and $PO_2$ were inversely proportional to arterial blood. Differences of $PCO_2$ between arterial blood and urine also did not have any particular correlation with urinary volume. This may suggest that changes on blood gas tensions can influence on urinary $PCO_2$. 4. There were eminent clear inverse correlation between urinary $PCO_2$ and osmolar concentrations of urine. Above results strongly suggest that partial pressure of gas in urine primarily depend upon counter-current exchanges in renal medullary tissues.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.408-415
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• 2016

Small fishing ports and coastal structures installed in a relatively low sea water depth disturb the wave induced current and cause the collapse of equilibrium state of sediment transport. These structures creates diffracted waves and matter the concentration of waves to cause the beach erosion. In order to mitigate these eroding problems on the beach, many counter measurements were proposed such as detached breakwater, groin or headland; however, these methods interrupt the aesthetic view of sandy beach due to the exposed structures above the sea level and have difficulty of applying to those beaches with the good scenery. Furthermore, some of these methods create secondary environmental problems after the installations. To eliminate these problems, one of the countermeasures, artificial reefs have been selected and used worldwide to minimize the disturbance of the scenery and secondary effects on the environment. Meanwhile, it is important to set the design elements for installing the artificial reefs such as that of length, opening width, clearing distances from the shoreline and more. Nevertheless, there are no construction manuals or standards for designing the artificial reefs with these important design elements yet. In this study, different conditions of artificial reefs were used with various cases throughout hydraulic model test to precisely analyze the changes of waves and currents to propose the standards of design elements to install the artificial reefs.

• Korean Journal of Acupuncture
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• v.28 no.4
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• pp.1-15
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• 2011

Objectives : The purpose of this study is to evaluate the feasibility of massive clinical research and to make a basic analysis on the effectiveness and safety of moxibustion treatment on knee osteoarthritis compared to usual care. Methods and Results : This study is a protocol for a pilot randomized controlled trial. Forty participants are assigned to the moxibustion group (n=20) and usual care group (n=20). Participants assigned to the moxibustion group receive moxibustion treatment on the affected knee(s) at six standard acupuncture points (ST36, ST35, ST34, SP9, Ex-LE04 and SP10) three times per week for four weeks (total of 12 sessions). Participants in the usual care group don't receive moxibustion treatment during the study period and follow-up are made on the 5th, 9th and 13th weeks after random allocation. Both groups are allowed to use any kind of treatment, including surgery, conventional medication, physical treatment, acupuncture, herbal medicine, over-the-counter drugs and other active treatments. Education material that explains knee osteoarthritis and current management options and self-exercise is provided for each group. The pain scale of the Korean Western Ontario and McMaster Universities Questionnaire (K-WOMAC) is the primary outcome measurement used in this study. Other subscales of the K-WOMAC, the Short-Form 36 Health Survey (SF-36), Beck Depression Inventory (BDI), Physical Function test, Patient Global Assessment, and Pain Numeric Rating Scale (NRS) are used as outcome variables to evaluate the effectiveness of acupuncture. Safety is assessed at every visit. Conclusions : The result of this trial will provide a basis for the effectiveness and safety of acupuncture treatment for knee osteoarthritis.

• Korean Journal of Acupuncture
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• v.30 no.3
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• pp.185-192
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• 2013

Objectives : Many studies have investigated the electric specificity of meridian and acupoint. However, the definition about the real substance of 'Ki(Qi)' that flows in the meridian has not been established yet. The authors hypothesized that the 'Ki(Qi)' may be the very 'bioelectricity' of western medicine, from two common features that they are not visible with naked eyes and that they function in the living body only. Methods : 20 healthy adults participated in this study. Heart rate was measured before and after exercise. Acupuncture was performed at PC6 immediately after exercise with counter balance in the first experiment. In the second experiment, acupuncture group was further divided to the three groups, i.e. glove acupuncture group, manual acupuncture group, and NaCl acupuncture group. In the glove group, acupuncturist put on the two folds of latex gloves to block bioelectric currents between the acupuncturist and subject. In the NaCl group, acupuncturist had his fingertips wet with NaCl solution. Results : Exercise increased Heart Rate and acupuncture at PC6 inhibited this increase. In the second experiment, the significant difference compared to the comtrol group was the most in NaCl acupuncture and the least in Glove acupuncture. However, there was no significant difference between three groups. Conclusions : The results of this study seem to be deficient as a conclusive evidence for the hypothesis that the 'Ki(Qi)' of Korean Medicine is the 'bioelectricity' of western medicine.

• Clean Technology
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• v.5 no.1
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• pp.78-85
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• 1999

In the Kimchi manufacturing industry that has recently been on its greatest growth, the rinsing process for salt-pickled Chinese cabbage in a brining step generates a vast amount of rinsing wastewater containing salts, colloids, and organics released from the raw material. In this study, the experimental method was developed to optimize the rinsing water consumption and thus to minimize the rinsing wastewater generation. The continuous counter-current rinsing basin in the actual plant was simulated through the lab-scale three batch-wise rinsing tanks. Rinsing efficiencies for the brined cabbage from the same brining tank were almost in the same level, whereas those varied substantially from source to source in the raw Chinese cabbage provided. When rinsing water used were decreased from 3.3 L/head to 2.7 L/head, no significant change was observed with respect to COD, turbidity, conductivity, $Na^+$, and $Cl^-$ concentrations in the extracted solution of the rinsed cabbage. However, the quality of the extracted solution was badly deteriorated as the amount of rinsing water used dropped down to below 2.7 L/head. The reduction of rinsing water up to 18% was proved to be possible without any negative effect on the quality of the product, Kimchi.