• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.676-681
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• 1997

The purpose of this study is to evaluate the thermal Conductivity and Foolr Impact Sound of Polyurethane Concretes. The Polyurethane Concretes are prepared with various resin content, Fine and Coarse aggregates content, and its thickness, and tested for the Thermal Conductivity and Impact Sound. From the test results. the sound insulation grade of polyurethane concretes by the floor impact sound test on high frequency band is L-60, and its effect is considerable Polyurethane concretes have high degree of solidity compared with other heat shield materials, and its thermal conductivity is 0.05kcal/$mh^{\cire}C$. And it is suitable for sound proof floor materials.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.451-456
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• 2004

In this study, evaluation was carried out for reduction method of floor impact noise through field test and the effective methods for heavy impact noise were proposed. As a field test, impact noise reduction materials such as EPP, EEPS, EVA, PE and so on, did not satisfied the recommandation value at the condition of 150mm thickness concrete slab. The evaluation results for those materials by 'inverse A curve' showed $53\sim55dB$ at heavy impact noise and $53\sim58dB$ at light impact noise. But, two methods proposed by authors were evaluated $47\sim50dB$ at heavy Impact noise and $54\sim58dB$ at light Impact noise on the similar concrete slab thickness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.506-511
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• 2000

The aim of this study is to suggest a fundamental data to improve the sound insulation performance of floor. To achieve the aim of this study, 8 types of sound-absorbing and sound insulation materials were installed under the slab, and the floor systems were compared to the general floor system which was composed of slab, timber frame, gypsum board and wallpaper.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.1
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• pp.1-6
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• 1993

The maxillary squamous cell carcinoma is major part of maxillary malignant tumor. The treatment of maxillary malignancy tumor is the maxillectomy in combination with radiation therapy and chemorherapy. When tumor invasion is occured to the orbit, orbital exenteration is required. But if the periosteum of the orbital floor is intact, the orbit can be preserved. There are many orbital floor reconstruction materials for the prevention of ptosis of the orbital content. The patients on this paper were diagnosised as squamous cell carcinoma on maxilla, we performed the partial maxillectomy including the orbital floor, and we used temporalis muscle-coronoid process flap for the reconstruction of the orbital floor after partial maxillectomy and obtained good esthetic and functional results, as followed. 1. We obtained sufficient flap width for defect of orbital floor. 2. It permits good blood supply and no necessary other donor site. 3. It gives a solid base for the support the globe and the orbital floor. 4. It gives minimal postoperative morphorogical defect and functional disturbance.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.93-101
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• 2006

Recently the floor vibration of apartment is often beginning to make its appearance of the environmental dispute, the standard floor system of housing are suggested for the settlement of this issue by government. For the slab vibration analysis on the laminated floor system of apartment, it is required the effectively analytical method of the floor system considering laminated theory. In this paper, more effective modeling methods of laminated floor slab are proposed for the method of accurate rigidity evaluation. By using the advanced modeling method, the more accurate vibration response can be obtained and can accurately evaluate the rigidity of living room floor system of apartment with different laminated materials.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.465-473
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• 2005

The impact sounds, generated by the walking of people, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The characteristics and level of this impact noise depends on the object striking the floor, on the basic structure of the floor, and on the finish materials of floor. The focus of this paper is to investigate the amount of improvement impact sound pressure level according to the change of the composition method of ceiling and wall. For this purpose, we tested impact sound pressure level of several cases which is the inserting of mineral wool, the increase of the thickness of air layer, the using of anti-vibration rubber in ceiling and attach the mineral wool on wall in the Floor Impact Sound Test Building of KICT. The results show that the composition method of ceiling and wall is more effective in the reduction of light weight impact sound specially in 125Hz and 250Hz.

• Imaging Science in Dentistry
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• v.39 no.2
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• pp.69-73
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• 2009

Purpose: This study compared panoramic radiography and cone beam computed tomography (CBCT) for evaluating the relationship between the maxillary sinus floor and the roots of maxillary molars. Materials and Methods: Paired panoramic radiographs and CBCT images from 97 subjects were analysed. This analysis classified 388 maxillary molars according to their relationship to the maxillary sinus floor on panoramic radiograph and CBCT. Correlations between these two radiographic techniques were examined. Results: Maxillary molar roots that were separate from the sinus floor showed the same classification in 100% of the cases when using these two imaging techniques. The corresponding percentage for such roots that were in contact with the sinus floor was 75%. When roots overlapped the maxillary sinus floor on panoramic radiographs, only 26.4% of maxillary first molars and 60.0% of second molars showed protrusion of roots into the sinus with CBCT. Conclusion : The results of the study suggest that roots projecting into the sinus on panoramic radiographs require a three-dimensional image in order to analyze the proximity of their apex to the sinus floor. (Korean J Oral Maxillofac Radiol2009; 39 : 69-73)

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.345-359
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• 2006

Loss of maxillary molar teeth leads to rapid loss of crestal bone and inferior expansion of the maxillary sinus floor (secondary pneumatization). Rehabilitation of the site with osseointegrated dental implants often represents a clinical challenge because of the insufficient bone volume resulted from this phenomenon. Boyne & James proposed the classic procedure for maxillary sinus floor elevation entails preparation of a trap door including the Schneiderian membrane in the lateral sinus wall. Summers proposed another non-invasive method using a set of osteotome and the osteotome sinus floor elevation (OSFE) was proposed for implant sites with at least 5-6mm of bone between the alveolar crest and the maxillary sinus floor. The change of grafted material in maxillary sinus is important for implant survival and the evaluation of graft height after maxillary sinus floor elevation is composed of histologic evaluation and radiomorphometric evaluation. The aim of the present study was radiographically evaluate the graft height change after maxillary sinus floor elevation and the influence of the graft material type in height change and the bone remodeling of grafts in sinus. A total of 59 patients (28 in lateral approach and 31 in crestal approach) who underwent maxillary sinus floor elevation composed of lateral approach and crestal approach were radiographically followed for up to about 48 months. Change in sinusgraft height were calculated with respect to implant length (IL) and grafted sinus height(BL). It was evaluated the change of the graft height according to time, the influence of the approach technique (staged approach and simultaneous approach) in lateral approach to change of the graft height, and the influence of the type of graft materials to change of the graft height. Patients were divided into three class based on the height of the grafted sinus floor relative to the implant apex and evaluated the proportion change of that class (Class I, in which the grafted sinus floor was above the implant apex; Class II, in which the implant apex was level with the grafted sinus floor; and Class III, in which the grafted sinus floor was below the implant apex). And it was evaluated th bone remodeling in sinus during 12 months using SGRl(by $Br\ddot{a}gger$ et al). The result was like that; Sinus graft height decreased significantly in both lateral approach and crestal approach in first 12 months (p$MBCP^{TM}$ had minimum height loss. Class III and Class II was increased by time in both lateral and crestal approach and Class I was decreased by time. SGRI was increased statistically significantly from baseline to 3 months and 3 months(p<0.05) to 12 months(p$ICB^{(R)}$ single use, more reduction of sinusgraft height was appeared. Therefore we speculated that the mixture of graft materials is preferable as a reduction of graft materials. Increasing of the SGRI as time goes by explains the stability of implant, but additional histologic or computed tomographic study will be needed for accurate conclusion. From the radiographic evaluation, we come to know that placement of dental implant with sinus floor elevation is an effective procedure in atrophic maxillary reconstruction.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.246-255
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• 2006

In these days the floor vibration is beginning to make its appearance of the environmental dispute in apartment building. Standard floor system are suggested for the settlement of this issue by government. The sound of floor impact sound is needed to secure comfortable quality in housing. Also, it is required an accurate analysis and a proper evaluation for floor vibration. Refine model is necessary for the floor system of housing to analyze accurately the floor vibration. But this refine model is not efficient because it is required so much running time for vibration analysis and it is difficult of modeling of standard floor slab. In this paper, new modeling methods of standard floor slab are proposed for the accurate rigidity evaluation. By using the new modeling method, the accurate vibration response can be obtained and can accurately evaluate the rigidity of standard floor system with resilient materials. Therefore the proposed modeling method is of practical use for vibration analysis of floor system of apartment building.

• The Journal of the Acoustical Society of Korea
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• v.40 no.6
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• pp.671-677
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• 2021

The present study aims to investigate the influence of the water to binder ratio of finishing mortar on the floor impact sound of apartments. For this, same resilient materials Expanded Polystyrene (EPS) with constant dynamic stiffness and different mortar layers with 52 %, 66 % and 72 % water to binder ratio respectively were used to build floating floor structures on which floor impact sounds were measured in standard testing facilities. As a result, it was found that light-weight floor impact sound was transmitted well when the water to binder ratio was 52% due to the high density. In case of heavy-weight floor impact sounds, since water to binder ratio of finishing mortar becomes higher as the weight of upper layer of resilient material lighter, it was shown that the natural frequency of floating floor structure moves to 63 Hz bandwidth which eventually cause a higher sound pressure level of floor impact sound. Thus, effect of water to binder ratio of mortar on the heavy-weight floor impact sounds was investigated.