A Study on Thermal Modeling and Heat Load Mitigation for Satellite Electronic Components

Since most of the satellite components are using various EEE (Electrical, Electronic and Electromechanical) parts, the reliability of EEE parts acts very important in the satellite system. There are many factors that influence the reliability of EEE parts in the satellite system. Excessively dissipated heat can cause the failure of EEE parts and consequently, leading to a failure of total satellite system. In this paper, the thermal modeling using nodal network was compared with that using plate modeling to find out which one is the most suitable methodology. For a comparison, KOMPSAT- 1 SAR was modeled by two different modeling and the result was discussed. There was almost no difference in the numerical results between the two modeling methods. However, while it took much more time to perform thermal analysis using the nodal network modeling method, and the debugging was more difficult in the plate modeling method when the error is occurred. The computation time was considerably reduced by developing and implementing the input file format transfer code when using nodal network modeling method. It was found that the nodal network modeling method is suitable for the complicated components, such as SAR or transponder, because of its simple debugging ability. Excessive heat load was expected on some EEE parts of SAR such as high heat-dissipated diodes, transistors, and inductors due to increased power requirements of KOMPSAT-2 satellite system. The methods for the mitigation of heat load were studied through the design change of housing or the layout change of high power parts

Bocavirus Infection in Hospitalized Children, South Korea

This study presents the first evidence of human bocavirus infection in South Korean children. The virus was detected in 27 (8.0%) of 336 tested specimens, including 17 (7.5%) of 225 virus-negative specimens, collected from children with acute lower respiratory tract infection

Development of Threat Evaluation Tool for Distributed Network Environment

Current information protection systems only detect and warn against individual intrusion, and are not able to provide a collective and synthesized alert message. In this paper, we propose a new Meta-IDS system which is called ``SIA System''. The SIA system can filter redundant alert messages, analyze mixed attacks using correlation alert messages from each sensor and respond to security threats quickly, after classifying them into one of four different statuses. Then we implement the SIA system and test the efficiency of it in the managed networks. Thus we confirm that the SIA system enables security managers to deal with security threats efficiently

Permanent Hydrophilic Surface Formation by Ion Assisted Reaction

Since totally wettable hydrophilic polymer surfaces from hydrophobic polymers (PMMA, PTFE, PET and PC) have been demonstrated for the first time at Materials Research Society meeting, 1995 Fall meeting, Boston, the application of ion assisted reaction (IAR), in which energetic ions (0.5~1.5 keV) are irradiated on materials with blowing reactive gases near the irradiating surfaces, has been extended to various polymer, ceramic and metal for creating permanent hydrophilic surfaces. The surface energy was measured by Youngs equation and the highest energy, Es, of 60~70 mN/m, which is similar to surface energy of water (Es of H2O : 72 mN/m) is obtained by controlling ion dose, energy, and amount of blown gas. The higher surface energy of materials possesses the more wettable surface, and relation between wettability and adhesion has been discussed. The remarkable result is the strong adhesion of inert nonattachable material such as Pt on the modified surface. The improvements of adhesions, wettability and surface energy are mainly due to polar force and hydrophilic functional groups such as C=O, (C=O)-O, C-O, etc. on the modified surface without surface damage by surface analyses. Advantages of the method are (1) high reproducibility, (2) simplicity, (3) changing ability of wettability degree, and (4) easy connection to conventional semiconductor process line. Improvements of efficiencies by changing heat transfer coefficients have been presented for the compact heat exchanger system

Gastric Syphilis Mimicking Adenocarcinoma: A Case Report

Syphilis is an unexpected diagnosis in the stomach, and the reduced incidence of syphilis has made its clinical presentation less widely appreciated. We report a 43-yr-old man suffering from epigastric tenderness with an initial diagnosis of gastric carcinoma; gastric syphilis was confirmed by demonstrating spirochetes in a gastric biopsy specimen by silver impregnation. Excessive lymphoplasmacytic infiltration with diffuse thickening of gastric rugae should raise suspicion of gastric syphilis, which should be considered in the differential diagnosis of diffuse erosive gastritis and infiltrative lesions of the stomach

Effect of Mechanical Deformation on in Vitro Calcification of Segmented Polyurethane

To investigate why calcification is accelerated by mechanical flexure, in vitro calcification of segmented polyurethane (SPU) under static elongation and dynamic mechanical flexure was performed. After the calcification period, the amount of calcium deposition was increased by elongation, but the amount of calcium deposition per unit area of the elongated surface was relatively smaller as compared to that of the severe flexing area. Although the surface calcium concentration of the elongated SPU was relatively smaller than the flexed area, there was the increase of surface area by the elongation. The total amount of deposited calcium on the elongated SPU was increased as it is reduced to the original surface area. Therefore, the results reveal that certain changes of surface properties by the Mechanical deformation accelerate the calcium deposition onto the surface and the enlargement of surface area by the mechanical deformation results in the heavy calcification of the severe flexing area in the SPU

A case of hepatoblastoma misdiagnosed as combined hepatocellular carcinoma and cholangiocarcinoma in an adult

Hepatoblastoma usually occurs in children under the age of 2 years, with very few cases reported in adults. We experienced a case of adult hepatoblastoma in a 36-year-old female with chronic hepatitis B. She had experienced sudden onset abdominal pain. Her serum alpha-fetoprotein level was markedly elevated, and abdominal CT showed a 9-cm mass with internal hemorrhage in the right hepatic lobe with hemoperitoneum, so an emergency hepatic central bisectionectomy was performed. The initial histologic examination revealed that the mass mimicked combined hepatocellular carcinoma and cholangiocarcinoma with spindle-cell metaplasia of the cholangiocarcinoma element. Follow-up abdominal CT performed 3 months later showed a 5.5-cm metastatic mass in the left subphrenic area. Laparoscopic splenectomy with mass excision was performed, and hepatoblastoma was confirmed histologically. A histologic re-examination of previously obtained surgical specimens also confirmed the presence of hepatoblastoma. Metastatic hepatoblastoma was found at multiple sites of the abdomen during follow-up, and so chemotherapy with cisplatin, 5-fluorouracil (5-FU), and vincristine was applied, followed by carboplatin and doxorubicin. Despite surgery and postoperative chemotherapy, she died 12 months after symptom onset

Trophic niche of a neustonic copepod community sustained by local production in high- and low-salinity summer water masses in the northeastern East China Sea

We investigated the trophic dynamics between neustonic copepod communities and particulate organic matter (POM) sourced from contrasting water masses, i.e., high- and low-salinity areas, within the northeastern East China Sea. The sampling of neustonic copepod communities occurred three times in the summer (June, August, and September) of 2021, and considered the influx of the Yangtze River Diluted Water (YRDW) and the extension of the Tsushima Warm Current (TWC). To examine the relationship between the neustonic copepods and surface POM, we employed stable isotope techniques. Surprisingly, the neustonic copepod community exhibited a reluctance to feed on surface POM. The neustonic copepod community in the YRDW-dominated area in August showed higher δ13C values than those in the TWC-dominated area. The trophic groups within the neustonic copepod population appeared to consume selectively depending on the individual preferred prey sizes and composition. Using the POM from the water masses that affected the food sources consumed by neustonic copepods, we found a strong dependence on prey items originating from the TWC. This result suggests that the marine neustonic copepod community does not rely significantly on food sources derived from riverine freshwater

Wolff-Parkinson-White Syndrome in a Patient With Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-Like Episodes Syndrome

Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome is a multisystem disorder, which is clinically characterized by encephalopathy, dementia, seizures and stroke-like episodes. Multiple organs can be affected and cardiac involvement often dominates the clinical picture because of its high energy requirement. We report a case of a 21-year-old woman with MELAS syndrome who had pre-excitation ECG and one episode of tachycardia attack