• Proceedings of the KSME Conference
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• 2004.04a
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• pp.72-77
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• 2004

In a primary reactor cooling system(RCS), a dissimilar weld zone exists between cast stainless steel(CF8M) in a pipe and low-alloy steel(SA508 cl.3) in a nozzle. Thermal aging is observed in CF8M as the RCS is exposed for a long period of time to a reactor operating temperature between 290 and $330^{\circ}C$, while no effect is observed in SA508 cl.3. The specimens are prepared by an artificially accelerated aging technique maintained for 300, 1800 and 3600 hrs at $430^{\circ}C$, respectively. The specimens for elastic-plastic fracture toughness tests are prepared one type, which notch is created in the heat affected zone(HAZ) of CF8M. And, the specimens for fatigue crack growth tests are prepared in three classes, which notches are created at the center of deposited zone, the HAZ of CF8M, and the HAZ of SA508 cl.3. From the experiments, the J-integral values with the increase of aging time decrease, and the differences of the fatigue crack growth behaviors are relatively small in the three classes specimens.

• Tuberculosis and Respiratory Diseases
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• v.54 no.6
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• pp.635-639
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• 2003

An extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) is the most frequent type of non-Hodgkin's lymphoma that primarily involves the lung. The radiographical discovery of a pulmonary lesion in an asymptomatic patient is the most common clinical presentation. In general, the prognosis of a localized extranodal pulmonary marginal zone B-cell lymphoma of MALT type is excellent. We report a case of a 61-year-old man who sought evaluation of an incidentally discovered mass in the lung.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.118-125
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• 2024

Tamai zone 4 replantation, defined as the replantation at a level proximal to the flexor digitorum superficialis' insertion and distal to where the common digital artery branches into the proper digital artery, has poor functional results because making orthosis and rehabilitation protocols that protect the bone and the flexor and extensor tendons simultaneously difficult. Two cases of Tamai zone 4 replantation are presented: one case of an index finger replantation at the proximal phalanx and a case of ring finger replantation at the proximal interphalangeal joint. The author did not repair the flexor tendon intentionally in the primary replantation and performed two-stage flexor tendon reconstruction later. The total active motions (TAMs) at the last follow-up were 215 and 180 degrees, respectively, with the latter distal interphalangeal joint being an arthrodesis. Both cases had no extension lag in the proximal interphalangeal joint. These results were much better than those in previous reports, in which the mean TAM was 133 degrees or less. The good results appeared to be mainly due to the reasonable and clear postoperative rehabilitation protocols made by the proposed procedure. This procedure may be useful for obtaining reproducible functional results even in Tamai zone 4 replantation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.32-38
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• 2003

Staged combustion, such as air- and fuel-staging, is a relatively well-known technique fur reduction of NOx emission and used in combination with other techniques nowadays. However, the design variables are still selected depending upon operating conditions. There are many variables tested to investigate the NOx emission characteristics fur changing of fuel or air velocity, swirl intensity, and staging ratio of air and fuel in multi-staged burner. In air-staging case, the fuel-rich condition of the primary combustion zone is very helpful to reduce NOx emission and its range is known to be restricted by the increase of carbon monoxide. However, in many cases carbon monoxide level is not too high to be restricted operating condition. So we tried to expand the equivalence ratio range to the richer condition in the primary combustion zone and certificate the function of each burner component and its contribution to the overall NOx production.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.564-567
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• 2002

Primary malignant lymphoma of the lung is a very rare disease, which consists of 0.34% of entire malignant lymphoma. The majority are low-grade B-cell tumors, and because of their morphological peculiarities and overall excellent prognosis, many cases, like many other extranodal lymphomas, have been mislabelled as "pseudolymphomas" in the past. For these reasons their true incidence is difficult to estimate. An incidentally discovered mass in the right middle lobe of a 36-year-old woman was operated on November 9, 2001 at Hanyang University Hospital. A right upper lobectomy was done and the pathologic diagnosis of extranodal marginal zone B-cell lymphoma of MALT type was made.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.71-74
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• 2007

Large Eddy Simulation(LES) has been conducted to insight interaction effects of turbulent flow and chemical reaction of a lean-Premixed swirl combustor. The unsteady turbulent flame is carefully simulated so that the motion of flow and flame can be characterized in detail. Fuel lumps escaping from the primary combustion zone move downstream and consequently produce local hot spots conveying large vortical structures in the azimuthal direction. The correlation between pressure oscillation and unsteady heat release is examined by the spatial and temporal Rayleigh parameter.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.67-75
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• 2013

The numerical analysis for the verification of preburner's cooling characteristics applying to kerosene-LOx rocket engine has been fulfilled. The distribution of combustion gas properties in primary combustion zone was calculated by the mixture ratio based on head injector arrangement, the properties of oxygen flowing in wall channels as coolant were applied under real-gas conditions, and multi-phase mixing model was employed to calculate the mixing process of primary combustion zone with liquid oxygen which was used for wall cooling. The results of numerical analysis were compared with the experimental results, hence thermo-physical properties in cooling channels and a combustor could be quantitatively identified.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1136-1144
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• 1999

The collision-induced reaction of gas-phase atomic hydrogen with hydrogen atoms chemisorbed on a silicon (001)-(2×1) surface is studied by use of the classical trajectory approach. The model is based on reaction zone atoms interacting with a finite number of primary system silicon atoms, which then are coupled to the heat bath, i.e., the bulk solid phase. The potential energy of the Hads‥Hgas interaction is the primary driver of the reaction, and in all reactive collisions, there is an efficient flow of energy from this interaction to the Hads-Si bond. All reactive events occur on a subpicosecond scale, following the Eley-Rideal mechanism. These events occur in a localized region around the adatom site on the surface. The reaction probability shows the maximum near 700K as the gas temperature increases, but it is nearly independent of the surface temperature up to 700 K. Over the surface temperature range of 0-700 K and gas temperature range of 300 to 2500 K, the reaction probability lies at about 0.1. The reaction energy available for the product states is small, and most of this energy is carried away by the desorbing H2 in its translational and vibrational motions. The Langevin equation is used to consider energy exchange between the reaction zone and the bulk solid phase.

• Archives of Craniofacial Surgery
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• v.22 no.5
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• pp.280-284
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• 2021

Primary cutaneous marginal zone B-cell lymphoma (PCMZL) is an uncommon type of malignant lymphoma that mainly occurs in the trunk and upper extremity, with less frequent incidence observed on the head. Herein, we report the early diagnosis and treatment of a rare case of facial PCMZL in an Asian patient. A 51-year-old man presented with masses on the forehead and nose tip, which he had incidentally discovered 2 months previously. The masses appeared as a papule on the forehead and a patch on the nose. There were no signs of infection or bleeding, and the patient reported no other symptoms. After complete surgical excision, PCMZL was diagnosed based on the permanent biopsy. The histopathological findings revealed lymphoid aggregations with multifocal granulomas. Further treatment and follow-up were conducted at the hematology and oncology department. Despite its rarity in Asian populations, cutaneous lymphoma should be included in the differential diagnosis of facial masses. Early diagnosis and treatment based on a physical examination, imaging study, and excisional biopsy are important for a favorable prognosis.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2769-2774
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• 2007

In vacuum ejector-diffuser systems where a finite volume secondary chamber is used, the secondary jet exhibits transient characteristics during start-up. A steady state is achieved after some time in which mass entrainment prevails indefinitely inside the ejector, though there is no flow from the secondary chamber. An attempt is made in this work to study the infinite entrainment of secondary jet into the primary jet from a finite secondary chamber, with the help of a computational fluid dynamics method. The present study is also intended to identify the operating range of vacuum ejector-diffuser systems where the steady flow assumption can be applied without uncertainty. The results obtained show that the only condition in which an infinite mass entrainment is possible is the generation of a re-circulation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium at this point. Steady flow assumption is valid only after this point.