• Journal of KIISE:Databases
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• v.29 no.3
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• pp.217-229
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• 2002

Regular path expressions are primary elements for formulating queries over the semistructured data that does not assume the conventional schemas. In addition, the query pruning is an important optimization technique to avoid useless traversals in evaluating regular path expressions. However, the existing query pruning often fails to fully optimize multiple regular path expressions, and the previous methods that post-process the result of the existing query pruning must check exponential combinations of sub-results. In this paper, we present a new query pruning technique that consists of the preprocessing phase and the pruning phase. Our two-phase query pruning is affective in optimizing multiple regular path expressions, and is more scalable than the previous methods in that it never check the exponential combinations of sub-results.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.139-144
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• 2008

The results of microstructure observations of the $Al_2O_3$ scale formed on a Fe-Cr-Al steel during high temperature oxidation in the $SO_2$ atmosphere are presented. Morphology of the scale has been studied by SEM and TEM techniques. Phase and chemical compositions have been studied by EDX and XRD techniques. The alumina oxide is a primary component of the scale. TEM observations showed that the scale was multilayer. The entire surface of the scale is covered with "whiskers", which look like very thin platelets and have random orientation. The cross section of a sample shows, that the "whiskers" are approximately $2{\mu}m$ high, however the compact scale layer on which they reside is $0.2{\mu}m$ thick. The scale layer was composed mainly of small equiaxial grains and a residual amount of small columnar grains. EDX analysis of the scale surface showed that the any sulfides were found in the formed outer and thin inner scale layer. A phase analysis of the scale formed revealed that it is composed mainly of the $\theta-Al_2O_3$ phase and a residual amount of $\alpha-Al_2O_3$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.12
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• pp.654-662
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• 2017

When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

• Journal of Gastric Cancer
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• v.17 no.4
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• pp.354-362
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• 2017

Purpose: Laparoscopic gastrectomy is accepted as a standard treatment for patients with early gastric cancer in Korea, Japan, and China. However, duodenal stump leakage remains a fatal complication after gastrectomy. We conducted a prospective phase II study to evaluate the safety of the new technique of laparoscopic reinforcement suture (LARS) on the duodenal stump. Materials and Methods: The estimated number of patients required for this study was 100 for a period of 18 months. Inclusion criteria were histologically proven gastric adenocarcinoma treated with laparoscopic distal or total gastrectomy and Billroth II or Roux-en-Y reconstruction. The primary endpoint was the incidence of duodenal stump leakage within the first 30 postoperative days. The secondary endpoints were early postoperative outcomes until discharge. Results: One hundred patients were enrolled between February 2016 and March 2017. The study groups consisted of 65 male and 35 female patients with a mean age (years) of 62.3. Of these, 63 (63%) patients had comorbidities. The mean number of retrieved lymph nodes was 38. The mean operation time was 145 minutes including 7.8 minutes of mean LARS time. There was no occurrence of duodenal stump leakage. Thirteen complications occurred, with one case of reoperation for splenic artery rupture and one case of mortality. Conclusions: Based on the results of this prospective phase II study, LARS can be safely performed in a short operation period without development of duodenal stump leakage. A future randomized prospective controlled trial is required to confirm the surgical benefit of LARS compared to non-LARS.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.50-57
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• 2013

Characterization of microstructures and cryogenic mechanical properties of electro beam (EB) welds between cast and forged Inconel 718 superalloys has been investigated. Optimal EBW condition was found in the beam current range of 36~39 mA with the constant travel speed of 12 mm/s and arc voltage of 120 kV for 10 mm-thick specimens. Electron beam current lower than 25 mA caused to occur the liquation microfissuring in cast-side heat affected zone (HAZ) of EB welds. The HAZ liquation microfissure was found on the liquated grain boundaries with resolidified ${\gamma}/Laves$ and ${\gamma}/NbC$ eutectic constituents. EBW produced welds showing a fine dendritic structure with relatively discrete Laves phase due to fast cooling rate. After post weld aging treatment, blocky Laves phase and formation of ${\gamma}^{\prime}+{\gamma}^{{\prime}{\prime}}$ strengtheners were observed. Presence of primary strengthener and coarse Laves particles in PWHT weld may cause to reduce micro-plastic zone ahead of a crack, leading to a significant decrease in Charpy impact toughness at $-196^{\circ}C$. Fracture initiation and propagation induced by Charpy impact testing were discussed in terms of the dislocation structures ahead of crack arisen from the fractured Laves phase.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.661-666
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• 1998

Liquid phase adsorption equilibria of amines in an aqueous solution onto high silica zeolite pellets (HSZ), macroreticular resin particles (MR) and granular activated carbon (GAC) were determined using a batch bottle technique at 298K. The isotherm curves of HSZ-amines and GAC-amines indicate the nonlinear relationship of unfavorable adsorption type of HSZ-amines and favourable one of GAC-amines. However the curves of MR-amines represent the linear pattern of an adsorption isotherm. Among various equilibrium isotherms, the three parameters of the Redlich-Peterson equation and the two parameters of the Freundlich equation are found to be the most satisfactory within the range of this study. The two parameters of the Langmuir isotherm were not applicable to the present adsorption systems. The amines were adsorbed on the HSZ, MR and GAC in the following sequence of adsorptivity; aromatic amines > primary amines > secondary amines. The product of the Freundlich constants, k and n, proportionally increased with the boiling point, molar volume and dissociation constants of amines adsorbed on HSZ, MR and GAC.

• Journal of Gastric Cancer
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• v.19 no.2
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• pp.157-164
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• 2019

Purpose: Although standard radical gastrectomy is recommended after noncurative resection of endoscopic submucosal dissection (ESD) for early gastric cancer in most cases, residual tumor and lymph node metastasis have not been identified after surgery. The aim of this study is to evaluate the feasibility of sentinel node navigation surgery after noncurative ESD. Materials and Methods: This trial is an investigator-initiated, multicenter prospective phase II trial. Patients who underwent ESD for clinical stage T1N0M0 gastric cancer with noncurative resections were eligible. Qualified investigators who completed the prior phase III trial (SENORITA 1) are exclusively allowed to participate. In this study, 2 detection methods will be used: 1) intraoperative endoscopic submucosal injection of dual tracer, including radioisotope and indocyanine green (ICG) with sentinel basins detected using gamma-probe; 2) endoscopic injection of ICG, with sentinel basins detected using a fluorescence imaging system. Standard laparoscopic gastrectomy with lymphadenectomy will be performed. Sample size is calculated based on the inferior confidence interval of the detection rate of 95%, and the calculated accrual is 237 patients. The primary endpoint is detection rate, and the secondary endpoints are sensitivity and postoperative complications. Conclusions: This study is expected to clarify the feasibility of laparoscopic sentinel basin dissection after noncurative ESD. If the feasibility is demonstrated, a multicenter phase III trial will be initiated to compare laparoscopic sentinel node navigation surgery versus laparoscopic standard gastrectomy in early gastric cancer after endoscopic resection.

• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.28-38
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• 2010

High temperature high cycle and low cycle fatigue deformation behavior of automotive heat resistant aluminum alloys (A356 and A319 based) were investigated in this study. The microstructures of both alloys were composed of primary Al-Si dendrite and eutectic Si phase. However, the size and distribution for eutectic Si phase varied: a coarse and inhomogeneous distributed was observed in alloy B (A319 based). A brittle intermethallic phase of ${\alpha}-Fe\;Al_{12}(Fe,Mn)_3Si_2$ was detected only in B alloy. Alloy B exhibited high fatigue life only under a high stress amplitued condition in the high cycle fatigue results, whereas alloy A showed high fatigue life when stress was lowered. With regard to the low-cycle fatigue result ($250^{\circ}C$) showing higher fatigue life as ductility increased, alloy A demonstrated higher fatigue life under all of the strain amplitude conditions. Fractographic observations showed that large porosities and pores near the outside surface could be the main factor in the formation of fatigue cracks. In alloy B. micro-cracks were formed in both the brittle intermetallic and coarse Si phasese. These micro-cracks then coalesced together and provided a path for fatigue crack propagation. From the observation of the differences in microstructure and fractography of these two automotive alloys, the authors attempt to explain the high-temperature fatigue deformation behavior of heat resistant aluminum alloys.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.3
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• pp.89-97
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• 2021

PURPOSE: This study examined the effects of coordinative locomotor training on the spine appearance and quality of life of patients with idiopathic scoliosis. METHODS: This study included two patients with idiopathic scoliosis: one with a thoracic and lumbar type scoliosis and the other with thoracic type scoliosis. The study design was a single case study (A-B-A'), with a baseline-intervention/phase-post-intervention. The baseline (A) was designed and measured five times, intervention phase (B) ten times, and post-intervention (A') five times. The coordinative locomotor training program was divided into 10 minutes of warm-up exercise, 30 minutes of the main exercise, and 10 minutes of the finishing exercise, for 50 minutes each time. The primary outcome measurements were measured using the Cobb's angle, Adam's test, and Gait view pro 2.0 to determine the changes in the spine appearance. The secondary outcome measurements were compared before and after using the SRS-22 questionnaire to determine the quality of life of the scoliosis patients. A statistical test analyzed the mean and standard deviation, and the rate of change was presented by a visual analysis method using descriptive statistics and graphs. RESULTS: The findings showed that the spine appearance and quality of life of the two subjects were improved compared to the baseline measurements during the intervention phase, and the improved state was maintained during the post-intervention period. CONCLUSION: These findings indicate that coordinative locomotor training may help improve the spine appearance and quality of life of patients with idiopathic scoliosis.

• Ocean and Polar Research
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• v.44 no.3
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• pp.221-233
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• 2022

A sediment trap had been deployed at 1250 m depth in the Eastern Tropical Pacific (ETP) from September 2009 to July 2010, with the aim of understanding the temporal and vertical variability of particle flux. During the monitoring period, total particle flux varied from 12.4 to 101.0 mg m^-2day^-1, with the higher fluxes in January-March 2010. Biogenic particle flux varied in phase with the total particle flux. The increase in total particle flux during January-March 2010 was attributed to the enhanced biological production in the surface layer caused by wind-driven mixing in response to the seasonal shifts in the location of the Intertropical convergence zone. The export ratio (e-ratio) was estimated using the particulate organic carbon flux and satellite-derived net primary production data. The estimated e-ratios changed between 0.8% and 2.8% (1.4±0.6% on average). The ratio recorded in the negative phase of Pacific decadal oscillation (PDO) was similar to the previous results obtained from the ETP during the 1992/93 periods in the positive phase of PDO. This suggests that the regime shift of the PDO is not related to the carbon export ratio.