• Composites Research
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• v.21 no.4
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• pp.7-14
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• 2008

Prediction of the load-bearing capacity of an adhesive-bonded Joint is of practical importance for engineers. This paper introduces interface fracture mechanics approach to predict the load-bearing capacity of composite metal bonded joints. The adhesion strength of composite/steel bonding is evaluated in terms of the energy release rate of an interfacial crack and the fracture toughness of the interface. Virtual track closure technique (VCCT) is used to calculate energy release rates, and hi-material end-notched flexure (ENF) specimens are devised to measure the interfacial fracture toughness. Bi-material ENF specimens gave consistent mode II fracture toughness $(G_{IIc})$ values of the composite/steel interface regardless of the thickness of specimens. The critical energy release rates of double-lap joints showed a good agreement with the measured fracture toughness. Therefore. the energy-based interfacial fracture characterization can be a practical engineering tool for predicting the load-bearing capacity of bonded joints.

• Journal of Wind Energy
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• v.14 no.3
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• pp.83-90
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• 2023

The purpose of this study is to evaluate the inter-laminar fracture toughness characteristics of CFRP pultrusion spar cap materials reinforced with non-woven glass fabric. Test specimens were fabricated by the infusion technique. A non-woven glass fabric and artificial defects were embedded on the middle surface between two pultruded CFRP panels. Double cantilever beam (DCB) and End Notched Flexure (ENF) tests were performed according to ASTM standards. Fracture toughness and crack propagation characteristics were evaluated with load-displacement curves and delamination resistance curves (R-Curve). The fracture toughness results were calculated by compliance calibration (CC) method. The initiation and propagation values of Mode-I critical strain energy release rate value G_Ic were 1.357 kJ/m2 and 1.397 kJ/m2, respectively, and Mode-II critical strain energy release rate values G_IIc were 4.053 kJ/m2 for non-precracked test and 4.547 kJ/m2 for precracked test. It was found that the fracture toughness properties of the CFRP pultrusion spar-cap are influenced by the interface between the layers of CFRP and glass fiber non-woven.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.119-128
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• 2011

In the process of assessing the children with anterior crossbite in early mixed dentition, it has frequently been detected that the stronger the skeletal pattern of the malocclusion is, the more markedly delayed the development and eruption of maxillary teeth are. If the anteroposterior characteristics of craniofacial skeleton has any relationship with dental maturation, the evaluation of dental development and eruption was thought to be able to contribute to early diagnosis of crossbite in children. This study was performed for the purpose of elucidating the relationship between dental maturation of maxillary teeth and some cephalometric values in children with anterior crossbite of maxillary undergrowth type in early mixed dentition. Among the children in Hellman dental age IIA and IIC who attended the Pediatric Dental Clinic of Pusan National University Hospital with orthodontic problems, cases with Class III malocclusion were classified and 50 cases of maxillary undergrowth type and type with normal maxilla respectively were randomly selected and studied as subjects. From their lateral cephalographs and panoramic radiographs, their anteroposterior skeletal features, the dental maturity and eruption rate were obtained of each group and data were analyzed to yield the results as follows: 1. Comparing the maturity of maxillary teeth of both groups, only the first molars of maxillary undergrowth group showed significantly slower development and eruption (p<0.05). 2. There was high correlation between maturation of maxillary 1st molar and chronological age(p<0.05). 3. Among the parameters of anteroposterior relationship of skeletal pattern in maxilla and mandible. Wits was revealed as a useful index to predict both the calcification and eruption rate of the 1st molars whereas SNA was to eruption rate(p<0.05).

• Journal of Gastric Cancer
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• v.4 no.4
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• pp.213-218
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• 2004

Purpose: The superficial spreading type of early gastric cancer has different clinicopathologic features from other types of early gastric cancer in terms of its invasiveness and lymph-node metastases. Therefore, we attempted to elucidate the pathological features, surgical procedures and patients prognoses. Materials and Methods: Clinical information was reviewed for patients who had undergone a gastrectomy for gastric cancer during an 8-year period ($1995\~2002$) at Dankook University Hospital and Ulsan University, with an average follow-up of 48 months. Three hundred (300) superficial spreading lesions were analyzed with respect to macroscopic type, lymph-node (LN) metastasis, recurrent pattern, survival rate and method of surgical operation. In addition, the clinicopathological features of the superficial spreading type were compared with those of 739 other patients with small-sized cancer. Results: In both groups, the IIc-type macroscopic lesion, the elevated subtype to be more specific, occurred most frequently. There was no significant difference in the method of surgery between the groups. The submucosal invasion was $39.8\%$ in small-sized cancer, and $61.7\%$ in superficial spreading cancer (P=0.005). The incidence of LN metastasis was $11.3\%$ in early gastric cancer, $7.8\%$ in small-sized cancer and $20.0\%$ in superficial spreading cancer (P=0.005). The incidence of lymphatic invasion was $4.6\%$ in small-sized cancer and $13.0\%$ in superficial spreading cancer (P=0.009). The incidence of recurrence was $1.4\%$ in small-sized cancer and $3.6\%$ in superficial spreading cancer. The overall 5-year survival rate was $84.8\%$ in superficial spreading cancer and $93.0\%$ in small-sized cancer (P=0.052). The 5-year diseasefree survival rate was $94.7\%$ in superficial spreading cancer and $87.5\%$ in small-sized cancer (P=0.053). Conclusion: The superficial spreading type of early gastric cancer tends to be more invasive and to show a higher incidence of lymph-node metastasis than small-sized early gastric cancer. A wide resection with extensive lymph-node dissection seems to be an appropriate treatment for a superficial spreading type of early gastric cancer.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.65-89
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• 2004

Up to now, the studies for a pond of ancient palace of Korea are mainly achieved in a landscape architectural field. In fact, we can't grasp the general aspects but we are only heard about the fragmentary ruins and remains by the people who are in charge of an archaeological excavation. In this thesis, therefore, I attempt to grasp the relational categories of the ponds of an ancient palace of Korea, and find out the ideological backgrounds of the ponds of a palace construction through classify them excavated so far. The ancient ponds of Korea are divided to the class of square ponds(I) and curved ponds(II) according a shapes of planes. The class of square ponds(I) are subdivided to the form IA of the class of square ponds and form IB of the class of square ponds by whether it has an island, artificial hill and ornamental stone or not. And the class of the curved ponds(II) are divided to the form IIC that is only composed of curves in shore and the form IID that is composed of curves and straight lines. According the size, it is divided to a small size that is below the maximal diameter, 20m, and a large size that is more than 45m, after all, the ponds of the ancient palaces are devided to IAa, IAb, IBa, II Ca, IICb, IIDa. The square ponds and the curved ponds are co-exist from the initial stage when a pond of a place was found in our country and are succeeded or changed after Silla unified the three Kingdoms. In other words, we can infer a continuity from the earlier stage from the fact that there is a flat figure ground mainly constituted by the ponds of a palace mixed up of a straight line and a curved line in United Silla Kingdom while it succeeds the ponds of a palace that has a square form of Goguryo in Balhai. Different from the successional relation of the flat figure grounds, in an aspect of the elements of the construction, the site of the arbor at the top of the island and the bridge facilities in a field of a palace those are not exist in three Kingdoms period are appeared in United Silla Kingdom. The point that this aspect is simultaneously appeared in a neighboring country, or Japan, allows us to infer that there may be some motivations cause the changes in a construction of the ponds of a palace of Korea, China and Japan from the latter half of the 7th century to the first half of the 8th century. The ideological backgrounds of the ponds of a palace construction are divided roughly into Taoism and Buddhism. We can recognize that the ponds of a palace made up of the islands, the artificial hills and the garden rocks reflect Taiosm, considering the records of the ponds a palace of Korea and China are all use the term, Taoism, or the concrete statement represents that the islands, the artificial hills and the garden rocks are used in the description of the ponds of a palace of Korea. Both two are, therefore, obviously differentiated from the ponds of a palace that doesn't include them. We can conclude that the ponds of a palace that doesn't include them are colored by Buddhism since they are overtly distinguished from the class of curved ponds that reflect Taoism at the same period and they are identical with the site of an ancient temples in an aspect of their type and construction.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.251-258
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• 2010

Despite significant advance in laparoscopy, upper gastrointestinal (UGI) series is still generally carried out for preoperative localization of gastrectomy. The aim of the study was to compare the accuracy of UGI series and postoperative pathological findings in the diagnosis and localization of gastric cancer. A retrospective review was carried out for 102 patients who underwent gastrectomy between October 2007 and April 2009. Preoperative reports of UGI series were compared with postoperative pathology reports and the accuracy of the preoperative reports was calculated. Two radiographer retrospectively reviewed the analysis of UGI series. postoperative pathology reports of the surgical specimens, were compared with the preoperative reports of the location and extent of the tumor were correct in 81 case("sure", 79.4%) and incorrect in 21 case("failed, 20.6%). In 92 case UGI series revealed intestinal metaplasia (90.2%) at consensus review and these results demonstrate the limitation of the UGI series in the diagnosis of type IIb gastric cancer with size less than 1.0cm and the poor detection of gastric cancer is that the overlying mucous membrane often appears to be normal in these patients. In conclusion, UGI series is accurate the detection of the tumor localization and diagnosis of intestinal metaplasia. However, for the overcome with the limitation of UGI series should be used accurate technique for the region of the stomach. To achieve this goal, it is necessary to determine the changes of the mucus membrane of the stomach and UGI series is gaining acceptance as a standard method for preoperative gastric cancer screening.

• Journal of Yeungnam Medical Science
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• v.14 no.2
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• pp.393-398
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• 1997

An accurate early diagnosis of congenital midgut malrotation is essential to prevention of catastrophic effects of volvulus. To evaluate the usefulness of radiologic examinations in diagnosing intestinal malrotation, we retrospectively analyzed radiologic findings and operation records of 17 intestinal malrotation patients, who were radiologically diagnosed. The age range of the patients studied were from 1day to 12years. The presenting symptoms were vomiting, vomiting with abdominal pain, abdominal distention, diarrhea and failure to thrive. The viewpoints of this analysis were the location of duodeno-jejunal flexure on barium meal and cecal location on barium enema. Sixteen of 17 patients, who were radiologically diagnosed, were surgically proven, but one patient with annular pancreas was false positive. In the case of 3 surgically proved patients, malrotation was suspected on barium meal prior to the barium enema, but final diagnosis was determined on barium enema examination. We concluded that a barium enema should be performed on all children with suspected malrotation where the initial upper gastro-intestinal study was normal or suspicious on account of the small incidence of false positive and false negative barium meals.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.150-154
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• 2001

Purpose: Multiple early gastric cancers were found in $6.9\∼11.7\%$ of patients with early gastric cancer. The goal of this study was to clarify the clinicopathologic features of and to investigate treatment strategy for multiple early gastric cancer. Materials and Methods: Of 967 patients with an gastric adenocarcinoma who were treated by surgical resection during the period of $1993\∼1998$ at the Department of Surgery, Korea University College of Medicine, 267 patients had early gastric cancer. A retrospective analysis of the clinicopathologic differences between the main and the accessory lesions in multiple early gastric cancer was carried out. A comparative analysis was also conducted between solitary early gastric cancer and multiple early gastric cancer. Results: Of 267 patients with early gastric cancer, multiple early gastric cancers were found in 12 patients ($4.5\%$), including 10 men and 2 women. Eleven patients with multiple early gastric cancer had one accessory lesion and 1 patient had 2 accessory lesions. Of the 13 accessory lesions, 7 ($53.8\%$) were located in the same region as the main lesion. The most frequent combination of macroscopic types for the main lesion and the accessory lesion were depressed and depressed types (6 cases, $46.1\%$). The most frequent histologic type of main lesion was a well differentiated adenocarcinoma in 7 ($58.3\%$) of the 12 cases; the accessory lesion was also well differentiated in 4 of those 7 cases. Of the 13 accessory lesions, 4 ($30.8\%$) had been overlooked preoperatively; most of them were located in the lower third of the stomach and were IIb or IIc type and measured less than 1 cm in diameter. Lymph node metastasis was detected in 1 patient ($8.3\%$). The clinicopathologic features of multiple early gastric cancer were not different from those of solitary early gastric cancer. Conclusion: In multiple early gastric cancer, the main and the accessory lesions showed similar differentiation, and lymph node metastasis was less frequent than in solitary early gastric cancer. Therefore, limited procedures, including endoscopic mucosal resection, may be indicated if each lesion of the multiple early gastric cancer fits the criteria for treatment strategy.

• Composites Research
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• v.29 no.2
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• pp.45-52
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• 2016

An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

• Applied Microscopy
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• v.25 no.4
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• pp.26-51
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• 1995

The present study was designed to examine effect of long term weight-training on aging atrophy in the rat skeletal muscle. Male rats of 8, 15, and 24 month old were used. Each age groups included control and weight-training for 5 months by using body press apparatus. The histo- and cytochemical, ultrastructural and stereological changes in aging skeletal muscles of the rat were observed in the present study. During the training period the body weight and muscular weight in all groups except the rectus femoris and the gastrocnemius in young age groups remained constant, but muscular weights were increased in the rectus femoris and the gastrocnemius muscles in young age groups. In trained rat, the volume density of muscle fiber type IIA and IIB were increased, but those of type IIC was decreased. Type I remained constant in 8 and 15 month old age groups, but reduced in the tibialis anterior and the gastrocnemius muscles in the 24 month old groups. Some histotological and ultrastructural changes associated with age were found: numerical increase of cytiplasmic vacuoles, lysosomes, lipofuscins, and irregularity of myofibrils. At 24 month old groups some unusual formation of contraction band and muscle splitting were observed. After weight-training, ultrastructural degenerative changes occured in the type I muscle fiber, such as splitting of muscle fiber, disorganization of myofilaments, swelling of mitochondria, accumulation of many lipid droplets, appearance of many lysosomes and residual bodies and necrotic fibers, in the old age groups. But, in the type II muscle fibers hypertrophy of muscle fiber appeared without any noticible damage as the type I. The activities of $Mg^{++}$ -ATPase decreased with age and this enzyme activities in the trained rat were significantly decreased with age. Activities of the acid phosphatase were increased with age and significantly in the trained rat. In stereological analysis, volume density of the myofibrils and the tubular system were increased, on the other hand there mitochondrial capacity was decreased. These experimental results suggested that old rats are not susceptible to be affected by weight-training as young rats, and that physical capacity of the rats must be considered when old rats are exercised for training.