• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.1
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• pp.75-80
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• 2008

The objective of this research was to investigate the enhancement of heat transfer by mesh in water/air direct contact air conditioning system. Mesh is inserted as a turbulent promoter in front of the water injection nozzle. The heat transfer characteristics with and without mesh and the effect of the number of inserted mesh and mesh porosity size have been studied experimentally. Inserted mesh improves heat transfer efficiency compared to non~inserted mesh system and heat transfer efficiency increased as the number of mesh is increased. Meanwhile, heat transfer efficiency decreased as the porosity of the mesh is increased. With inserted mesh, inlet and outlet temperature difference of air increased more than 50%. Heat exchange time of water/air to reach the 100% humidity decreased less than 30%. This result shows inserted mesh can enhance the performance of the water/air direct contact air conditioning system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.386-391
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• 2022

The gas insulation switchgear, which is a device for protecting a power system, cannot be supported by the insulation gas itself in a charge unit stored in a metal container. Therefore, molding technology is required to manufacture a gas insulation switch spacer. The APG method injection molding simulation was performed by applying the variables obtained through the physical properties of an epoxy composite used for manufacturing an insulating spacer to a moldflow software. After varying the temperature conditions of heater in the simulation, the thermal characteristics and the degree of hardening of the spacer were analyzed, based on which the optimum process conditions are presented.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.5
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• pp.262-269
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• 2022

In order to process materials such as engineering plastics, which are difficult to mold due to their high strength compared to conventional polymer materials, it is necessary to improve the hardness and strength of parts such as screws and barrels of injection equipment in extrusion system. High-velocity oxygen fuel (HVOF) process is well known for its contribution on enhancement of surface properties. Thus in this study, using the HVOF process, WC coating layers of different thicknesses were bonded to the surface of S30C substrate by controlling the movement speed of the spray nozzle and each property was evaluated to decide the optimization condition. Through the results, the thickness of WC coating layer increased from 0 to 200 ㎛ maximum, along with the decrement of nozzle movement speed and the surface hardness get increased. Especially, the coated layer with the thickness over 180 ㎛ under the nozzle speed 500 mm/s had high hardness than thinner layer. In addition, the amount of wear consumed per unit time was also significantly reduced due to the formation of the coating layer.

• Tuberculosis and Respiratory Diseases
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• v.43 no.4
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• pp.519-526
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• 1996

Background : Clinical and Radiographic studies to differentiate benign from malignant pulmonary nodules have previously focused on clinical status and the morphologic and the computed tomographic attenuation characteristics of the lung nodules. Distinctive differences in the vascularity and pathophysiology of malignant versus benign pulmonary nodules were identified. We evaluated the diagnostic method for differentiating malignant from benign solitary pulmonary nodule by contrast enhancement on the spiral CT. Method : Sixteen patients with solitary pulmonary nodule were examined(Tuberculoma 8, primary lung cancer 8). Serial thin section on the spiral CT was performed before and after(45second, 2min, 5min) the onset of the injection of 100mL of nonionic contrast material(2mL/sec). Results : There was no difference in size of nodule and pre-contrast CT number (Hounsfield unit) between benign and malignant nodules. At forty-five second after the onset of the injection, malignant neoplasms($19.6{\pm}7.9$ HU) enhanced significantly more than tuberculomas($4.9{\pm}9.4$ HU, p=0.008). At 2minute and 5 minute after, malignant neoplasms($34.0{\pm}19.2$HU, $34.0{\pm}15.4$HU) enhanced significantly more than tuberculomas ($6.7{\pm}9.7$HU, p=0.007 and $7.7{\pm}11.5$HU, p=0.011). On cut-off value 20HU(contrast enhancement) 2minute after the injection of contrast media, sensitivity was 87% and specificity was 87%. No correlation between the contrast enhancement and size of the nodules was observed. Conclusion : Studies with the use of an intravenously administered noniodinated contrast medium in examining the enhancement properties of lung nodules was performed. The contrast enhancement was useful in differential diagnosis of solitary pulmonary nodules.

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.22-29
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• 2001

Purpose : 99mTc DMSA renal scan have been widely used not only for tile evaluation of renal scars but also for the diagnosis of acute pyelonephritis. Recent studies have shown SPECT images have higher accuracy than the planar images with some controversy. We evaluated the availability of the SPECT images adding to planar images for the diagnosis of acute pyelonephritis(APN) and renal scar in children with urinary tract infection (UTI). Methods : 130 children with UTI (260 kidney units) and 22 follow-up children (44 kidney units) were included between January 1, 1997 and July 31, 1999 at Ewha University Mokdong Hospital. Planar Anterior and posterior images and SPECT axial and coronal images of 99mTc DMSA renal scan were obtained with Starcam 4000-i U.S.A. GE at 3 hours after 99mTc DMSA I.V. injection. The data were analyzed by Chi square test after Yates's correction. Results : The detection rate of the acute pyelonephritis by SPECT images was 12.3$\%$ higher than that of planar images ($47.7\%\;vs\;35.4\%$) by the patient and 6.9$\%$ higher also ($31.9\%\;vs\;25.4\%$) by the kidney unit. 18 kidney units with negative planar images had focal defect in 10 kidney units (3.8$\%$) and multifocal defect in 8 kidney units (3.1$\%$) on SPECT images, but 1 kidney unit with positive planar image had negative SPECT image. SPECT images were superior to tile planar images in 17.3$\%$. identical in 82.3$\%$ and inferior in 0.4$\%$ to planar image. The detection rate of tile renal scars by SPECT images was 13.7$\%$ higher than planar images by the patient ($68.2\%\;vs\;54.5\%$) and 6.8$\%$ higher also ($43.2\%\;vs\;36.4\%$) by the kidney unit. SPECT images were superior to the planar images in 17.3$\%$ and identical in 82.3$\%$ to planar image. Conclusion SPECT images had shown higher detection rate and better image than planar images for the diagnosis of the acute pyelonephritis and the evaluation of the renal scars. (J. Korean Soc Pediatr Nephrol 5 : 22- 9, 2001)

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.371-388
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• 2023

A stratum with a complex composition and a distributed low-permeability soil layer is difficult to remediate quickly because the soil remediation does not proceed easily. For efficient purification, the permeability should be improved and the soil remediation agent (H₂O₂) should be injected into the contaminated section to make sufficient contact with the TPH (Total petroleum hydrocarbons). This study analyzed a method for crack formation and effective delivery of the soil remediation agent based on pneumatic fracturing, plasma blasting, and vacuum suction (the PPV method) and compared its improvement effect relative to chemical oxidation. A demonstration test confirmed the effective delivery of the soil remediation agent to a site contaminated with TPH. The injection amount and injection time were monitored to calculate the delivery characteristics and the range of influence, and electrical resistivity surveying qualitatively confirmed changes in the underground environment. Permeability tests also evaluated and compared the permeability changes for each method. The amount of soil remediation agent injected was increased by about 4.74 to 7.48 times in the experimental group (PPV method) compared with the control group (chemical oxidation); the PPV method allowed injection rates per unit time (L/min) about 5.00 to 7.54 times quicker than the control method. Electrical resistivity measurements assessed that in the PPV method, the diffusion of H₂O₂2 and other fluids to the surface soil layer reduced the low resistivity change ratio: the horizontal change ratio between the injection well and the extraction well decreased the resistivity by about 1.12 to 2.38 times. Quantitative evaluation of hydraulic conductivity at the end of the test found that the control group had 21.1% of the original hydraulic conductivity and the experimental group retained 81.3% of the initial value, close to the initial permeability coefficient. Calculated radii of influence based on the survey results showed that the results of the PPV method were improved by 220% on average compared with those of the control group.

• Journal of Korean Medicine Rehabilitation
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• v.15 no.1
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• pp.127-141
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• 2005

Objectives : This study was performed to investigate the effects of Gamichangbaek-san(Jiaweichangbai-san) on anti-inflammatory, analgesic, anti-febrile and immune response on the arthritis of carrageenan-induced animals. Methods and Materials : Rats were classified into control and sample groups which are 7 individuals each for the experiments about anti-inflammatory and anti-febrile. Each of the 7 mice were classified into normal, control, sample groups for the analgesic experiments. Gamichangbai-san(Jiaweichangbai-san) was administered to sample group and normal saline was administered to normal and control groups. Arthritis was induced by injection of 1% carrageenan $0.1m{\ell}$ and Gamichangbaek-san(Jiaweichangbai-san) was administered after 30 minutes. The change of edema in Carrageenan-induced Arthritic Rats' Paws was measured after 1 hour and 5 hours from the injection of carraqeenan with Plethysmometer(7150, UGO BASILE, ltaly) by Winter' method. WBC, Lymphocyte and ESR were measured by heart puncture and CD4+ T cell, CD8+ T cell and CD4+/CD8+ T cell ratio were measured from the spleen tissue. Writhing syndrom was measured with Tail flick unit(UGO BASILE, Italy) in the experiments conducted to check the analgesic activity. The temperature of the paws of carrageenan-induced arthritic rats was measured by Laser thermometer. Rectal temperature was measured by Yeast's method in anti-febrile experiments. Immune response was measured by CD4+, CD8+ T cell ratio and CD4+/CD8+ T cell ratio. Results : 1. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased the increase rate of Paw Edema effectively with statistical significance. 2. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased WBC, Lymphocyte and ESR with statistically high significance. 3. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) did not show significant analgesic effect, but the Pressure pain threshold of the paws was increased with statistical significance. 4. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) decreased rectal temperature effectively and had an anti-febrile effect about the febrile of a joint with statistical significance. 5. It was recognized that Gamichangbaek-san(Jiaweichangbai-san) increased CD4+ T cell ratio with statistically high significance and increased CD+8 T cell ratio with statistical non significance but increased CD4+/CD8+ T cell ratio effectively with statistical significance, too. Conclusions : According to the above results, it can be concluded Gamichangbaek-san(Jiaweichangbai-san) showed the treatment effects on the artificial arthritis resulted from carageenan in rats and it is suggested that more interest and study in the security for the clinical use were needed.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.7 no.3
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• pp.415-428
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• 2000

The purpose of this study was to identify side effects of the vesicant chemotherapy. The study was designed to be a descriptive survey. The subjects of this study were 88 patients with various types of cancer, primary lung cancer(25.0%), advanced gastric cancer(25.0%), breast cancer(20.5%), etc. The mean age was 44.8 years old(range: 16-68). The questionnaire was completed by nurses of the outpatient unit and chemotherapy ward, and intravenous nurse specialist. The results of the study were as follows: 1) Chemotherapy was administered with a 23G scalp needle and 24G insyte. Injection site was dorsum of hands(64.7%), cephalic vein(19.3%). Successful rate for the first attempt was 88.6%. The first & second cycle chemotherapy was 29.5% each.. Mainly used drugs were Navelbine(34.1%), Adriamycin(20.5%). 2) Venous Problems after chemotherapy were pain(13.6%) incurred by venous, mainly due to the administration of Navelbine; redness at the inravenous site(12.5%) and itching sense 2.3% Non-venous problems were nausea (18.2%), dullness(14.8%), vomiting(8.0%), facial flushing(6.8%), anxiety(5.7%). Subjective discomforts after chemotherapy were generalized arm pain at the injection side(14.8%), dizziness(6.8%), weakness(5.7%) and general bodyache(5.7%). Systemic anaphylactic reaction and extravasation did not occur. 3) Non-venous problem after chemotherapy were nausea, vomiting & anorexia. Frequency of chemotherapy related to side effects were itching, facial flushing, and nausea(p< .05). Day of chemotherapy related to side effects were nausea & vomiting(p< .05). Site of chemotherapy related to side effects were redness(p< .05). Frequency of venipuncture related to side effects were redness(p< .05). Conclusively, cancer chemotherapy patients have had some venous problem. They need appropriate venous access devices for chemotherapy. And other non-venous problem will be managed appropriately. Further research was required to identify the rate of venous complication or side effects of vesicant chemotherapy.

• Analytical Science and Technology
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• v.18 no.1
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• pp.66-73
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• 2005

In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S$); methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide (DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit (TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among S compounds: $H_2S$ exhibited the lowest sensitivity, while DMDS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance.

• Health Policy and Management
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• v.16 no.2
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• pp.49-76
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• 2006

The aim of this study was to explore the effects of a computerized review program which was introduced in August 1, 2003, using claims data for acute respiratory infection related diseases. National Health Insurance (NHI) claims data on respiratory infection related diseases before and after the introduction, with six month intervals respectively, were used for the analysis. Clinic was the unit of observation, and clinics with only one physician whose specialty was internal medicine, pediatrics, otorhinolaryngology and family medicine and clinics with a general practitioner were selected. The final sample had 7,637 clinics in total. Indices used to measure practice pattern was prescription rates of antibiotics, prescription rates of injection drug per visit, treatment costs per claim, and total costs per claim. Changes in the number of claims for major disease categories and upcoding index for disease categories were used to measure claiming behavior. Data were analysed using descriptive analysis, t-test for indices changes before and after the introduction, analysis of variance (ANOVA) for practice pattern change for major disease categories, and multiple regression analysis to identify whether new system influenced on provider' practice patterns or not. Prescription of antibiotics, prescription rates of injection drug, treatment costs per claim, and total costs per claim decreased significantly. Results from multiple regression analysis showed that a computerized review system had effects on all the indices measuring behavior. Introduction of the new system had the spillover effects on the provider's behavior in the related disease categories in addition to the effects in the target diseases, but the magnitude of the effects were bigger among the target diseases. Rates of claims for computerized review over total claims for respiratory diseases significantly decreased after the introduction of a computerized review system and rates of claims for non target diseases increased, which was also statistically significant. Distribution of the number of claims by disease categories after the introduction of a computerized review system changed so as to increase the costs per claims. Analysis of upcoding index showed index for 'other acute lower respiratory infection (J20-22)', which was included in the review target, decreased and 'otitis media (H65, H66)', which was not included in the review target, increase. Factors affecting provider's practice patterns should be taken into consideration when policies on claims review method and behavior changes. It is critical to include strategies to decrease the variations among providers.