[en] Carcinoma of the stomach is usually considered a disease of middle aged or elderly patients and is rarely suspected in young adults. However carcinoma of the stomach in the young adults is an aggressive malignant disease with nonspecific symptoms and worse prognosis than older age group because of late diagnosis and increased incidence of undifferentiated form. In an attempt to identify further the natural history of carcinoma of the stomach in the young adults, we reviewed 68 cases of stomach cancers in patients 30 years of age and less at Severance hospital. The results were as follows: 1. The over-all male to female ratio in the young adult was 1:1.34 and in order age group was 2.44:1. 2. Common symptoms included epigastric pain, weight loss and vomiting. The mean time interval between onset of symptoms and the first visit to a physician was 3 months. 3. Usually diagnostic aids were UGI series and endoscopic examination. 38 patients underwent an exploratory laparatomy, and lesions were amenable to curative or palliative resection. 4. In the young age Bormann type III and IV were predominant, while in the older age group Bormann type II and III were common. 5. The majority of tumors occurred in the cardia, fundus and upper body. 6. Histologic diagnosis were poorly differentiated adenocarcinoma, signet ring cell carcinoma and anaplastic carcinoma in orders. 7. A relatively high incidence of pregnancy and Krukenberg tumor in the young age were noted

[en] The PEFP (Proton Engineering Frontier Project) will supply users with a 20-MeV proton beam by the middle of 2007. A survey on users' demand was performed to draw the concept for the 20-MeV user facilities and to investigate users' requirements. In the mean time, a 6-MeV test facility has been developed to give users opportunities to experiment with proton beams. That facility will be attached to the 3-MV tandem accelerator at Seoul National University.

[en] In the PEFP (Proton Engineering Frontier Project) the 100MeV linear accelerator is being developed for 20MeV and 100MeV user facilities. Also the individual beam line of the user facilities will be installed. In the 3 beam lines of 20MeV and 100MeV an exit window will be mounted respectively in the end of the vacuum beam tube for the external beam. The exit window made of the aluminum-beryllium alloy (AlBeMet) and determined as 30cm diameter and 0.5mm thickness. The exit window can be broken by high beam power of a peak current 20mA. To protection of an accelerator and a vacuum system we are consider to establish a FCV(Fast Closing Valve) in the beam lines. A closing time of the FCV is 15ms with 10cm diameter of the beam tube. In this study the test method of a closing time and of a shock wave of the air inrush using the FCV are introduced

[en] The PEFP (Proton Engineering Frontier Project) beamlines for 20-MeV and 100-MeV proton beams are under development as user facilities. The external beam window will be installed between a vacuum and air. Since the external beam window can be melted by a high beam current of 20 mA, the window can fail. To protect the accelerator and vacuum system from window failure, we adopted a fast closing valve (FCV) that can be closed within 15 ms. For a study on the validation of the FCV we set up test equipment composed of a FCV, a data acquisition (DAQ) system, and beam tubes of 20 m in length. This length is equivalent to the real dimension of a PEFP beamline. The valve was actuated by an air in rush trigger signal generated by a vacuum sensor located near the exit window. We made an artificial air in-rush by breaking aluminum windows of 0.1 mm and 0.2 mm in thickness. In this paper, the criteria and the details of the vacuum protection system will be reported.

[en] Understanding the fate of environmental contaminants is of fundamental importance in the development and evaluation of effective remediation strategies. Among the factors influencing the transport of these contaminants are the chemical speciation of the sample and the chemical and physical attributes of the surrounding medium. Characterization of the spatial distribution and chemical speciation at micron and submicron resolution is essential for studying the microscopic physical, geological, chemical, and biological interfaces that play a crucial role in determining contaminant fate and mobility. Hard X-ray spectroscopy and imaging are powerful techniques for the element-specific investigation of complex environmental samples at the needed micron and submicron resolution. An important advantage of these techniques results from the large penetration depth of hard X-rays in water. This minimizes the requirements for sample preparation and allows the detailed study of hydrated samples. This paper discusses some current problems in environmental science that can be addressed by using synchrotron-based X-ray imaging and spectroscopy. These concepts are illustrated by the results of recent X-ray microscopy studies at the Advanced Photon Source

[en] Thermal shock behavior was compared among the UO₂-5wt%CeO₂ pellets doped with various additives (0.1wt% Li₂O, SiO₂ , Al₂O₃ and 0.2wt% Cr₂O₃), sintered in H₂ atmosphere at 1700 .deg. C for 6h, in terms of the microstructure characteristics, quenching atmosphere Ar and 93N₂+7H₂ and temperature difference (ΔT=200∼1400 .deg. C). Vickers hardness was not affected by ΔT and thermal shock atmosphere. Fracture toughness (K_IC) of the doped pellets was nearly same as that of none-doped pellet in the ΔT range 200 to 800 .deg. C. The increase of K_IC value started at ΔT≥1200 in Ar and at ΔT≥1000 in reducing atmosphere

[en] Intergranular corrosion(IGC) of sensitized Alloy 600 has been studied with double loop-electrochemical potentiokinetic reactivation(DL-EPR) and Huey tests. Corrosion of solution annealed Ni-XCr-10Fe(X=6∼15) alloys was also evaluated with DL-EPR and Huey methods to simulate corrosion of Cr-depleted grain boundary region of Alloy 600. Cr concentration of Cr-depleted grain boundary region of Alloy 600. Cr concentration profile across grain boundary was measured with TEM. In the range of the Cr concentration from 6 to 8%, corrosion rates of solution annealed Ni-XCr-10Fe(X=6∼15) alloys were much higher in Huey test than those in DL-EPR. But in the range of the Cr concentration from 12 to 15%, the trend was reversed. The width of IGC crack of Alloy 600 was higher in DL-EPR test than in Huey test in agreement with corrosion of solution annealed Ni-XCr-10Fe alloys. Width of IGC produced by DL-EPR test was almost uniform and wide while that produced by Huey test was sharp and marrow. These results suggest that IGC in DL-EPR test conforms to uniform dissolution model and IGC in Huey test conforms to Cr concentration dependent dissolution model

[en] The mechanical properties of the UO₂-5wt%CeO₂ pellets were analysed in terms of porosity(density) and pore size distributions for UO₂-5wt%CeO₂ pellets by adding different amount of AZB poreformer to UO₂-5wt%CeO₂ and sintering at 1700 .deg. C in reducing atmosphere for 4 hour by measurement of the vickers hardness (Hv), fracture toughness (K_IC) and the fracture strength(σh). The vickers hardness (Hv) values of the mono and bi-modal pore size distributions UO₂-5wt% CeO₂ pellets show that the same levels with increase porosity, however, the mono-modal and large pore pellet has the lower values more than the mono and bi-modal. The fracture toughness (K_IC) values of the UO₂-5wt% CeO₂ pellets slightly increase with increase porosity and the mono-modal and large pore pellet show that the higher than the mono and bi-modal pellets. The fracture strength values of the mono and bi-modal UO₂-5wt% CeO₂ pellets were higher than the mono-modal and large pore pellet, and it's values silghtly increase at the 1000 .deg. C in the 93 and 95% T.D (porosity 3 and 5%) bi-modal UO₂-5wt% CeO₂ pellets

[en] Proton Engineering Frontier Project (PEFP) has developed a 100-MeV linear accelerator which has 20- MeV and 100-MeV user facilities. 5 beam lines for 100MeV target rooms for users have been designed to meet the requirements of the beam users. To provide flexibilities of irradiation conditions for various fields, we designed beam lines with wide external or vacuum, and horizontal or vertical beams. Table 1 shows detail specifications of each target room. High current beam lime will be mainly used for RI production and spallation neutron experiments such as TR101 and 105. We have a plan to make 3 multi purposed target rooms such as TR102, 103, and 104 also. Maximum irradiation area is 300-mm in diameter and the maximum average current is 300-μA of the 3 target rooms

[en] The Korea Institutes of Geoscinece and Mineral Resources (KIGAM) has done the studies based on electrostatic accelerator such as nondestructively analysis of proton induced X-ray emission (PIXE), proton induced gamma-ray emission (PIGE), Rutherford backscattering (RBS) and elastic recoil detection-time of flight (ERD-TOF). Current KIGAM is interested in measurement of neutron cross section data at energy ranges of 1 MeV to 2 MeV, which corresponds to field of fusion reaction. So KIGAM designed the nano-second beam bunching system and manufactured them for obtaining the accurate nuclear data by removing neutron backgrounds and by obtaining the accurate neutron energy. By using this system, we produced the pulsed beams with small width, and investigated their characteristics by time-of. flight (TOF) method. Their results are presented in this paper