• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.290-294
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• 1997

In this study, the welded residual stresses test was carried out with pure titanium and TIG welded material using in chemical plants an airplane frames etc.. The relationship between process parameters and residual stresses is complex since a number of factors are involved. Extensive studies have been carried out to determine the effects of various process parameters on residual stress. The result of micro-hardness about butt welded spacemen was measured of low hardness value in the melting metal zone. The residual stress of welded zone on the Titanium plate by the sectioning method and finite element method was high measured in the spacemen of high current and voltage. Also, compressive residual stress in the range of distance about 15∼20mm from the middle of the deposited metal area is very change. The result of impact test about butt welded spacemen of pure titanium plate was measured of very difference in the welded bead, heat affect zone and base metal, and be measured of high impact value in the heat affect zone. The measure result of welded residual stresses about pure titanium is high measured hen nominal steel plate. The V-Type butt welded spacemen, that of the measurement result on the welded residual stress is high measure then X-Type butt welded spacemen.

• Steel and Composite Structures
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• 제22권4호
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• pp.837-853
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• 2016

This paper presents the experimental and numerical study on the distribution of transverse and longitudinal residual stresses in cold-formed thick-walled structural steel rectangular hollow sections manufactured by indirect technique. Hole-drilling method is employed to measure the magnitude of the transverse and longitudinal surface residual stress distribution, and the effects of the residual stresses are evaluated qualitatively by sectioning method. It is shown that compared to normal cold-formed thin-walled structural hollow sections (SHS), the cold-formed thick-walled SHS has similar level of residual stress in the flat area but higher residual stresses in the corner and welding areas. Both the transverse and longitudinal residual stresses tend to open the section. In order to predict the surface residual stresses in the corners of the cold-formed thick-walled SHS, an analytical model is developed. 2D finite element simulation of the cold bending process is conducted to validate the analytical approach. It is shown that in analyzing bending for thick-walled sections, shifting of neutral axis must be considered, since it would lead to nonlinear and non-symmetrical distribution of stresses through the thickness. This phenomenon leads to the fact that cold-formed thick-walled SHSs has different distribution and magnitude of the residual stresses from the cold-formed thin-walled SHSs.

• International Journal of Korean Welding Society
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• 제2권1호
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• pp.40-44
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• 2002

Residual stress by welding should be reduced because that decreases the reliability on strength of welded structure. The reason is that the total stiffness of structure decreases by non-linear behavior of weldment under external load. The release of residual stress by mechanical loading and unloading is often performed in the fabrication of box structure for steel bridge. The proper degree of loading and unloading is significant at release method of residual stress by mechanical loading because that degree is changed by material and geometric shape of welded structure. Therefore, the simulation model that could exactly analyze the release of residual stress by mechanical loading is to be necessary. This simulation model should be established on the based of variable and accurate measurement data. In this study, the non-linear behavior of weldments under external loading and unloading, such as the decrease and increase of structure stiffness, was investigated by monitoring of nominal stress and strain. Tensile loading and unloading test under variable load was performed and the proper degree of stress relaxation was measured by sectioning technique using strain gauge.

• 한국임상수의학회지
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• 제20권3호
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• pp.278-285
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• 2003

개에서 실험적으로 앞쪽 십자인대 중간부를 절단한 다음 초기 병변을 관찰하고 그 초기 병변에 대한 conjugated linoleic acid (CLA), carprofen 그리고 두 약물의 병용에 따른 효과를 비교하고자 본 실험이 수행되었다. 실험견은 앞쪽 십자인대를 파열한 CLA 처치군, Carprofen 처치군, CLA와 Carprofen 병용처치군 그리고 양성대조군과 파열하지 않은 정상견으로 구성된 음성대조군으로 총 5개군으로 분류하고 각 군에 5두씩 배치하였다. 실험견의 무릎관절 외측 피부를 절개하고 관절낭 외측을 절개한 다음 앞쪽 십자인대 중간부로 판단되는 부위를 절단하였다. Carprofen과 CLA는 수술 후 4주부터 4주 동안 경구 투여하였다 수술후 8주 후에 육안적, 조직학적 평가를 실시하였다. 조직학적 검사로는 hematoxylin and eosin 염색, standard toluidine blue, PAS 그리고 Masson trichrome 염색법을 이용하였으며 혈액학적, 그리고 방사선학적 검사를 실시하였다. 조직학적 검사와 혈액학적 검사에서 유의적인 변화는 나타나지 않았다. 방사선 검사에서는 앞쪽 십자인대 파열에 따른 대퇴골과 경골의 정렬이상과 부종이 모든 군에서 나타났으며 육안적 검사에서는 대부분 실험견의 대퇴 연골 표면상이 엷은 황색을 보였다. 이상의 결과를 통하여 실험적으로 유발된 개의 앞쪽 십자인대 파열에 대해 CLA, carprofen그리고 이들의 합제는 초기 변화상에서 뚜렷한 변화를 나타내지 않았다.

• 대한후두음성언어의학회지
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• 제14권1호
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• pp.10-15
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• 2003

Background and Objectives : Ankyloglossia, commonly known as tongue-tie, is the result of a short, fibrous lingual frenulum or highly attached geioglossus muscle. This condition may cause sucking and swallowing problems, articulation disorders, interference with the tongue's cleansing action, increased the potential for caries, and inability to lick the lips, play a wind instrument, and 'french kiss' Treatment is surgical procedure. In the most cases, horizontal sectioning and mucosal suture(the conventional procedure) is preferred, but in some cases, the Z-plastic procedure is effective. This study is aimed to compare the result of the two procedures. Materials and Methods : Twenty tongue-tie patients underwent operation. Ten patients were treated with the Z-plastic procedure and ten patients were treated with the conventional method randomly. We checked preoperative mobile tongue length, postoperative mobile tongue length, operation time and postoperative wound states. Results : Among the 20 cases of tongue-tie, 2 cases are excepted due to pre-operative state, thus we compared 18 cases of tongue-tie patients. There is no statistically significant difference between the two procedures except in operation time. The Z-plastic procedure apparently needs a little more operating time. Conclusion : Patients treated with the Z-plastic procedures appeared to have better outcomes, but the data shows no statistical significance except in operating time. Consequently, the Z-plastic procedure is indicated in a limited amount of cases.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제16권2호
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• pp.167-170
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• 1994

The surgical removal of the wisdom teeth is obligate when forceps extraction fails or when the wisdom teeth are impacted. The surgical removal of impacted maxillary third molars is a commonly performed procedure usually associated with few complications & little morbidity. The most frequent complications are tooth root fracture, maxillary tuberosity fracture, tooth displacement into the maxillary sinus & oroantral fistula formation. A rarely reported complication is the displacement of a tooth into the infratemporal fossa. The method of prevention of this complication is by the placement of either a finger or periosteal elevator posterior to the tooth during extraction. To remove the displaced upper third molar is very difficult & has many complications, e.g., persistent bleeding & nerve damage. When the wisdom teeth is displaced, it is initially necessary to gain access to bone by developing a mucoperiosteal path of delivery is developed by additional bone removal or, preferably planned sectioning of the tooth. There are many approaching techniques to remove the displaced upper third molar. This following report describes the surgical technique of displaced upper third molar in the pterygopalatine fassa by the midpalatal ＆transpharyngeal approach.

• 대한치과의사협회지
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• 제9권12호
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• pp.819-822
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• 1971

For this investigation, author isolated Streptococcus mitis strain SD-9 from the bacterial flora in the human dental plaque, which was incubated in brain-heart infusion media containing 5% sucrose at 37℃ for 24 hours. For the cytochemical demonstration of polysaccharide produced by this strain, a modified thiosemicarbazide osmium method (Critchley et al., 1967) was used. After fixation with this reagent, the harvested cells was suspended in 1% agar for the higher concentration of cells(Kellenberger et al., 1964). And they were dehydrated in the various concentration of ethanol, and embedded in Epon 812(Luft, 1961). Sectioning was done with the Sorvall MT-2 Porter Blum ultramicrotome by means of a glass knife, and the sections were stained with saturated uranyl acetate and lead citrate (Raynolds, 1963). All preparations were examined in a electron microscope, Hitachi HU-ll E-1 type. The morphological features of extracellular polysaccharide produced by Streptococcus mitis strain SD-9 were appeared in 3 structurally different forms, those are, electron dense fibrillar material linearly arranged adjacent to the outer surface of cell wall, highly electron dense globular material adjacent to the outer surface of cell wall, and strutureless fluffy meshwork of possible very fine filament.

• The Journal of Advanced Prosthodontics
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• 제4권2호
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• pp.89-92
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• 2012

PURPOSE. Adequate passive-fitting of one-piece cast 3-element implant-supported frameworks is hard to achieve. This short communication aims to present an alternative method for section of one-piece cast frameworks and for casting implant-supported frameworks. MATERIALS AND METHODS. Three-unit implant-supported nickel-chromium (Ni-Cr) frameworks were tested for vertical misfit (n = 6). The frameworks were cast as one-piece (Group A) and later transversally sectioned through a diagonal axis (Group B) and compared to frameworks that were cast diagonally separated (Group C). All separated frameworks were laser welded. Only one side of the frameworks was screwed. RESULTS. The results on the tightened side were significantly lower in Group C ($6.43{\pm}3.24{\mu}m$) when compared to Groups A ($16.50{\pm}7.55{\mu}m$) and B ($16.27{\pm}1.71{\mu}m$) ($P$ <.05). On the opposite side, the diagonal section of the one-piece castings for laser welding showed significant improvement in the levels of misfit of the frameworks (Group A, $58.66{\pm}14.30{\mu}m$; Group B, $39.48{\pm}12.03{\mu}m$; Group C, $23.13{\pm}8.24{\mu}m$) ($P$ <.05). CONCLUSION. Casting diagonally sectioned frameworks lowers the misfit levels. Lower misfit levels for the frameworks can be achieved by diagonally sectioning one-piece frameworks.

• Clinical and Experimental Reproductive Medicine
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• 제40권3호
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• pp.115-121
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• 2013

Objective: Letrozole and estradiol valerate are used to treat some hormonally-responsive symptoms and also in modeling of the polycystic ovary syndrome. However, the stereological analysis of the ovary has received less attention. Estimation of the whole ovary volume using the Cavalieri method can be applied in any orientation desired, but estimation of the mean volume of the oocytes requires isotropic uniform random sectioning. Here, a combined method was developed for estimating the parameters. To our knowledge, no comparison has been made of the effects of letrozole and estradiol on the ovary. Methods: Sixty rats were divided into 4 groups receiving estradiol (4 mg/kg), olive oil, letrozole (1 mg/kg), or normal saline. After 21 days, their ovaries were studied. Results: Relative to the control group, the total volume of the ovary and the cortex increased in the letrozole-treated and estradiol-treated rats. In addition, the number of the preantral, antral, and granulosa cells decreased by 43% to 56% in the letrozole- and estradiol-treated rats. On average, a 19% increase was observed in the atretic oocytes of the letrozole-treated and estradiol-treated rats, but the mean oocyte volume decreased by 29% to 44% in letrozole- and estradiol-treated rats. Furthermore, the letrozole-treated rats showed a 5-fold and 7-fold increase in the volume of the cysts and corpus luteum, respectively. A 3-fold increase was found in the volume of both the cysts and corpus luteum in the estradiol group. Conclusion: The structural changes of the ovary were most pronounced in the letrozole-treated animals.

• Anatomy and Cell Biology
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• 제57권2호
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• pp.271-277
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• 2024

Human dentition is unique to individuals and helps in identification of individuals in forensic odontology. This study proposes to study the manually ground sections of single rooted teeth using digital methods for dental age estimation. To assess the dentinal translucency from the scanned digital images of manually ground section of teeth using commercially available image edition software. Corroborating the root dentinal translucency length and region of interest (ROI) of translucency zone in pixels (as a marker of dental age) with the chronological age of the subject, as stratified by different age groups. Twenty single-rooted extracted teeth from 20 patients each from 6 groups divided as per age. Manual sectioning of the teeth followed by scanning the sections was done. Root area in pixels and ROI of translucency zone were measured. From the observed values, translucency length percentage (TLP) and percentage of ROI in pixels (TPP) was calculated and tabulated. Pearson's correlation coefficients were obtained for age with TLP and TPP. Positive correlation existed between age and TLP and also between age and TPP. With the obtained data, multilinear regression equations for specific age groups based on 10-year intervals were derived. By a step-down analysis method, age was estimated with an average error of around ±7.9 years. This study gives a novel method for age-estimation that can be applied in real-time forensic sciences.