• The Journal of the Petrological Society of Korea
• /
• v.14 no.4 s.42
• /
• pp.251-263
• /
• 2005

Modern volcanoes, Laoheishan and Huoshaoshan, have erupted during $1720\~1721$ in the Wudalianchi volcanic group, NE china. They comprise scoria and spatter cones that consist of potassium-rich phono-tephritic pyroclastic deposits and lavas, and include wide lava flow fields. The Laoheishan scoria cone is a polygenetic multiple volcano that overlaps earlier and later edifices with more complicated internal structures produced in greater scale and in earlier time than the Huoshaoshan. There is a funnel-shaped crater in the center of the later edifice of the Laoheishan scoria cone. The Huoshaoshan spatter cone is a monogenetic simple volcano with a central pit crater. The volcanic sequences indicate eruption processes that followed a repeated pattern that progressed through 5 stages of explosive and effusive eruption including lava fountains and Strombolian eruptions in the Laoheishan, and a recognizable pattern of 2 stages that started with Strombolian eruption and progressed through lava effusion in the Huoshaoshan.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.27 no.2
• /
• pp.251-255
• /
• 2000

The strict meaning of the term retarded eruption is that tooth eruption is delayed compared to its developmental stage. The etiological factors for it may be local, systemic or genetic. Its pathogenic mechanism is unknown in most cases. In cases of generalized retarded eruption without any clear reason, the general growth and development seems normal in all aspects and the teeth usually keep the normal eruption sequence. Usually the primary teeth may often be extracted hoping to provoke the eruption of the retarded teeth, only to be proved a failure. Consequently, the patient will be without teeth for many years, with loss of esthetics, loss of occlusal height and resorption of alveolar process. The primary goal in the treatment may therefore be to keep and maintain the primary teeth in good condition until they are naturally shed. This observation was done on 10 year 1 month old patient who were diagnosed as idiopathic retarded eruption through both radiographic and systemic examination and follow-up observation was done for 11 month.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.2
• /
• pp.69.1-69.1
• /
• 2019

A series of numerical MHD simulations are performed to investigate the evolution of coronal magnetic fields consisting of two flux ropes and an overlying field. Depending on the directions of the axial current and the axial field, two co-helicity cases and two counter-helicity cases are addressed. In Case 1, in which both the axial currents and the axial fields are parallel, flux rope merging bears a huge flux rope with a large winding number. This flux rope naturally erupts, but the whole evolutionary process is rather slow. In Case 2, in which the axial currents are parallel while the axial fields are antiparallel, a self-closed structure is formed and it drives eruption. In Case 3, in which the axial currents are antiparallel and the axial fields are parallel, each flux rope erupts independently and the presence of the other flux rope does not affect the eruption of one flux rope. In Case 4, in which both the axial currents and the axial fields are antiparallel, interaction of the flux ropes and the overlying field effects a breakout reconnection creating an apple-like CME configuration. Our study tells what kind of eruption mechanisms are involved for different eruption features observed.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.26 no.2
• /
• pp.232-239
• /
• 1999

Exfoliation of the primary teeth and eruption of the permanent teeth is a normal and predictable physiologic process. The accurate prediction of tooth development is of major importance in treatment planning for children. Norms that correspond to the child's age and development have been determined by many investigators. However, there are a variety of factors that may hasten, retard, or otherwise affect the normal developmental process. Among the factors that influence tooth eruption is the premature loss of primary teeth. An abscess of a primary molar, followed by bone resorption and early extraction or exfoliation may lead to premature eruprion of the permanent succesor, and a variety of clinical sequelae. I, hereby present the patients who have prematurely erupted permanent successor in Seoul National University Hospital Pediatric Dentistry, and report the clinical and radiologic characteristics, its sequelae, proper managements, and followed up findings.

• Journal of the Korean Electrochemical Society
• /
• v.3 no.1
• /
• pp.19-24
• /
• 2000

It is increasingly necessary to use poly-Si n's as high resolution and integration of Tn for LCD. Excimer Laser Crystallization (ELC) of a-Si is mainly used as a low temperature process. But the ELC method for the fabrication of poly-Si has the eruption problems associated with hydrogen in the a-Si film. So we need a dehydro-genation process additionally. Hydrogen in a-Si film can degrade the quality of poly-Si film and electrical properties of device due to the hydrogen eruption and voids which occur during the excimer laser annealing. In this study, we propose mesh-type PECVD as the a-Si film deposition method for achieving the low concentration hydrogen. Mesh-type PECVD was found to reduce the hydrogen content substantially. We could obtain a as-deposited a-Si film with hydrogen contents less than $1\%$ at $300^{\circ}C$. We also investigated the behavior by XeCl excimer laser annealing of a-Si fabricated by mesh-type PECVB. As a result, we were able to confirm the broad process window in contrast to the narrow process range typically obtained in ELC. Hydrogen eruption was not observed in poly-Si films after ELC These results suggests that mesh-type PECVD is a viable method to achieve the low hydrogen content a-Si and improve the process windows for ELC.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.12
• /
• pp.7357-7363
• /
• 2014

Korea had been known as safe region regarding volcanic disasters. On the other hand, Baekdu mountain experienced a large eruption one thousand years ago and the precursor phenomena for a volcanic eruption have been frequently reported these days. Therefore, a number of volcano experts, who warn of a volcanic eruption on the Korean peninsula, has increased. This paper describes the utilization plan and evolution of developing volcanic disaster response system based on spatial information and scientific modeling process for Baekdu mountain. First, the business processes for volcanic disaster response are derived based on an analysis of business system and related IT-based systems. Second, the design and development of a volcanic disaster response system are derived based on the business process. Third, a utilization plan is suggested to maximize the efficiency of the system. The application of the suggested volcanic disaster response system to NEMA, additional tests and system supplementation should be carried out. The complete volcanic disaster response system, which will be implemented based on this research, is expected to minimize the volcanic disaster damage in the area of Korea, China and Japan.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.29 no.3
• /
• pp.444-449
• /
• 2002

The term 'impaction' is used to designate a tooth which remains unerupted in the jaw beyond the time at which it should normally be erupted. The main causal factors are local (lack of space, ectopic positions of teeth, supernumerary teeth, cyst, the occurrence of infectious process in the eruption path, traumatic facial injury etc.). Systemic and genetic disorders, however, may have primary failure of eruption and retarded eruption as additional symptoms (cleidocranial dysplasia, osteopetrosis etc.). Most cases of impacted teeth reported in the literature are of permanent teeth. The absence of primary teeth occur rarely whereas impaction of second primary molars is more numerous than all other impactions. Impaction due to primary failure of eruption must be distinguished from the secondary infraocclusion. The etiology of impaction of primary teeth is probably related to early ankylosis of primary teeth, but it is not clear. Failure of eruption of primary teeth may cause a number of complications, such as interference with development and eruption of succedaneous teeth, formation of cyst, and damage to adjacent teeth. This study is to report cases of primary failure of eruption in the primary dentition.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.1
• /
• pp.11-18
• /
• 2004

The eruption of permanent teeth represents the movement in the alveolar bone before appearance in oral cavity, to the occlusal plane after appearance in oral cavity, and additive movement after reaching th the occlusal plane. Tooth eruption is mostly controlled by genetic signals. The eruption stage is divided to preeruptive alveolar stage, alveolar bone stage, mucosal stage according to the process of growth and development. If the disturbance is occured in any stage of eruption, tooth does not erupt. The cause of eruption disturbance are ectopic position of the tooth germ, obstruction of the eruption path and defects in the follicle or PDL. In the treatment of eruption disturbance, surgical procedures are commonly used. There are three kind of surgical procedure ; surgical exposure, surgical repositioning, surgical exposure and traction Surgical exposure is basic procedure. This involves removal of mucosa, bone, lesion that are surrounding the teeth, dental sac when necessary to maintain a patent channel between the crown and the normal eruptive path into the oral cavity. To ensure this patency, many techniques including cementation of a celluloid crown, packing with gutta-percha or zinc oxide-eugenol, or a surgical pack, are used. When surgical exposure is conducted, operators should not expose any part of cervical root cement and not injure periodontium or root of adjunct tooth. After surgical exposure, tooth should be surrounded by keratinized gingiva. There is direct relationship between the extent of development of pathophysiologic aberrations and the intensity of the manipulative injury inflicted on the tooth by surgical treatment, so operator should consider this thing. In these cases, surgical exposure is conducted on Maxillary 1st milars that have a eruption disturbance and improve the eruption disturbance effectively.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.33 no.2
• /
• pp.290-303
• /
• 2006

Tooth eruption is a complex and tightly regulated process that involves cells of the tooth organ and the surrounding alveolus. Osteoclast precursors must be recruited into the dental follicle prior to the onset of eruption. This function of dental follicle may be regarded as the ability of bone remodeling characterized by the interaction of osteoclasts and osteoblasts. This is because tooth eruption is a localized event in which many of the genes required for eruption are expressed in the dental follicle. RANKL is a membrane-bound protein that is a member of the TNF ligand family. which is present on bone marrow stromal cells and osteoblasts, and induces osteoclast formation and activation from precursor cell. The biologic effect of RANKL is inhibited by OPG and, in bone, the relative ratio of RANKL and OPG modulates osteoclastogenesis. To evaluate the roles of RANKL and OPG in tooth eruption and the relations with the expression pattern of Runx2, in situ hybridization was performed with mandibles of mice at postnatal stage 1, 3, 5, 7, 9 and 11. mRNA of RANKL, OPG, and Runx2 are expressed in dental follicle and surrounding tissue from P1 to 11. To determine the sites of osteoclastic activity during tooth eruption, mandibles were dissected. Peak osteoclastic activity in alveolar bone along the occlusal and basal regions was observed from P5 to 9, with osteoclasts in these regions being large and strongly TRAP-positive The specific spatio-temporal expression patterns of RANKL, OPG, and Runx2 in our study suggest that tooth eruption could be progressed through the interactions of molecular signaling among dental follicle, dental organ and alveolar bone, furthermore it means that dental follicle is quite important in tooth eruption In addition, it indicates that these genes (RANKL, OPG, and Runx2) play critical roles in tooth eruption.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.35 no.3
• /
• pp.504-508
• /
• 2008

Delayed eruption and abnormal morphology of the primary incisors following intubation may be due to follicular displacement and localized trauma caused by the process of intubation. Result of such damage included palatal groove formation, defective incisors and acquired clefts. This clinical report presents effect of intubation on the primary dentition of premature low-birth-weight children prior to tooth eruption.