• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.5
• /
• pp.465-475
• /
• 2004

This paper is the first part of the study on the development of a smart active layer (SAL) sensor, which consists of two parts. In this first part, the theory and concept of the SAL sensor is investigated, which is designed for the detection of elastic waves caused by internal cracks and damages in structures. For the development SAL sensor, (i) the basic theory of elastic waves was studied, (ii) the feasible study of the SAL as an elastic waves detection sensor using the finite element analysis (FEA) with respect to a piezoceramic disc was performed. (iii) the comparison of performances between some piezoceramic sensors and a commercial acoustic emission (AE) sensor was accomplished to ensure the applicability by the experimental means, such as a pencil lead break test. Also, the conceptional study for the SAL sensor, which can be utilized for the effective detection and locating of defects by the arrangement of regularly distributed sensors, was discussed.

• Journal of Korean Foot and Ankle Society
• /
• v.19 no.4
• /
• pp.151-155
• /
• 2015

Purpose: The purpose of this study was to analyze the frequency and patterns of intra-articular lesions detected during ankle fracture surgery using ankle arthroscopy. Materials and Methods: Thirty patients (31 ankles) who underwent open reduction and internal fixation combined with ankle arthroscopy for acute ankle fracture at Inje University Busan Paik Hospital from June 2011 to September 2013 were evaluated. The ankle fractures were classified according to the AO/OTA (AO Foundation and Orthopaedic Trauma Association) classification and the intraarticular injuries were identified by ankle arthroscopy. Osteochondral lesions of the talus were divided into nine subtypes based on their locations, and the ligament injuries were classified according to avulsion fracture and rupture. Results: Using arthroscopy, abnormality in the distal tibiofibular ligament was found in 21 cases and osteochondral lesions and defects of the talus larger than 5 mm were detected in 26 cases. Among ligament injuries, anterior inferior tibio-fibular ligament injury was found in 14 cases, posterior inferior tibio-fibular ligament injury was found in two cases, deep deltoid ligament injury was found in three cases, and deep transverse tibio-fibular ligament injury was found in five cases. The locations of the osteochondral lesions were on the antero-lateral, antero-medial, centro-medial, centro-central, centro-lateral, and postero-lateral talus in 11, one, two, one, two, and nine cases, respectively. Conclusion: With early diagnosis and treatment arthroscopy performed at the time of intra-articular fracture surgery is expected to result in a good outcome.

• Journal of the Korea Computer Industry Society
• /
• v.6 no.2
• /
• pp.279-286
• /
• 2005

The prefabricated type used generally in Korea to join cable runs on new installations or to repair broken Cable runs on existing installations, because installation is very simple and save time. This type is a permanent, shielded and submersible cable joint for direct burial or vault application. It confirms to the requirements of IEEE std. 404-1993 by factory testing, but many problems of insulated cable systems are caused by internal defects of the joint part which have to be mounted ensile. Faults arise from impurities or voids. A suitable solution for a monitoring of cable joints during the after-laying test and service is partial discharge detection. <중략> $\Phi-q-n$ properties were measured using detection impedance, high pass filter and computerized data acquisition system. Statistic Value like maximum charge, repetition rate, average charge, etc. are calculated. It is possible to quantitative analysis of $\Phi-q-n$ properties from this statistic value and pattern analysis.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.35 no.3
• /
• pp.200-205
• /
• 2015

An ultra-precise infrared microscope consisting of a high-resolution infrared objective lens and infrared sensors is utilized successfully to obtain location information on the plane and depth of local heat sources causing defects in a semiconductor device. In this study, multi-layer semiconductor chips are analyzed for the positional information of heat sources by using a lock-in infrared microscope. Optimal conditions such as focal position, integration time, current and lock-in frequency for measuring the accurate depth of the heat sources are studied by lock-in thermography. The location indicated by the results of the depth estimate, according to the change in distance between the infrared objective lens and the specimen is analyzed under these optimal conditions.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.5
• /
• pp.454-461
• /
• 2015

Objective : In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements. Methods : A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development. Results : Tonsillar herniation length was measured $9.09{\pm}3.39mm$ below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased. Conclusion : Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

• Journal of Korea Foundry Society
• /
• v.37 no.1
• /
• pp.1-13
• /
• 2017

The purpose of this study is to increase the part recovery rate (to more than 70%) during the casting of a ductile cast iron turbo charger housing using a heater around the riser. Before creating a casting mold, various runner and riser systems were designed and analyzed with a casting simulation analysis tool. The design variables were the heater temperature, top insulation, riser location, riser diameter and the riser shape. During the feeding from the riser to the part, the reverse model was better than the forward model. When heating the riser (above $600^{\circ}C$), solidification of the riser was delayed and the feeding effect was suitable compared to that without heating. At a higher heating temperature, less solidification shrinkage and porosity were noted inside the part. On the basis of a casting simulation, eight molds were fabricated and casting experiments were conducted. According to the experimental conditions, external and internal defects were analyzed and mechanical properties were tested. The ultimate tensile strength and elongation outcome were correspondingly more than 540MPa and 5% after a heat treatment. In addition, a maximum part recovery rate of 86% was achieved in this study.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.7
• /
• pp.658-665
• /
• 2009

Quality control QC for spot-uniformity is a critical point in fabricating an oligonucleotide array, and quantification of targets is very important in array analysis. We developed two new types of QC probes as a means of confirming the quality of the uniformity of attached probes and the quantification of targets. We compared the signal intensities and fluorescent images of the QC and target-specific probes of arrays containing only target-specific probes and those containing both QC and target-specific probes. In a comparison of quality control methods, it was found that the arrays containing QC probes could check spot-uniformity or spot defects during all processes of array fabrication, including after spotting, after washing, and after hybridization. In a comparison of quantification results, the array fabricated by the method using QC probes showed linear and regular results because it was possible to normalize variations in spot size and morphology and amount of attached probe. This method could avoid errors originating in probe concentration and spot morphology because it could be normalized by QC probes. There were significant differences in the signal intensities of all mixtures (P<0.05). This result indicates that the method using QC probes is more useful than the ordinary method for quantification of mixed target. In the quantification of mixed targets, this method could determine a range for mixed targets of various amounts. Our results suggest that methods using QC probes for array fabrication are very useful to the quality control of spots in the fabrication processes of quantitative oligonucleotide arrays.

• Journal of Chest Surgery
• /
• v.10 no.1
• /
• pp.7-17
• /
• 1977

The increasing frequency of post-tracheostomy stenosis parallels the increase in the incidence of tracheostomy. The development of stenosis of trachea following the operation of tracheal tumor or tracheostomy is a very serious complication. The continuing need for an adequate tracheal substitute has not been answered, despite the necessities of excision and reconstruction of the trachea to keep for effective ventilation. Experimental tracheal reconstuction, with a prosthesis of heavy Marlex mesh and pericardium, _ vas performed in twelve dogs. Five to six tracheal ring circumferential defects were created and were bridged with heavy Marlex mesh fashioned into a tube of suitable diameter. Group A: A prepared cylinder of Marlex mesh was anastomosed outside the cut ends of the trachea. Group B: The external surface of the prepared cylinder of Marlex mesh was completely covered with suitably sized patch of pericardium and overlapped all margin of the Marlex mesh by 2 to 3 mm in each direction. Group C: The internal surface of the prepared cylinder of Marlex mesh was covered with suitably sized patch of pericardium and overlapped all margin of the Marlex mesh by 2 to 3 mm in each direction. The results of this exepriment were as follow: 1. In group A and B, the graft was well bridged with new granulation and fibrous tissue, and the lumen of trachea kept good patency for effective ventilation.. The interstices of Marlex became uniformly infiltrated with young well vasculated connective tissue. Epithelization has not yet occurred at 4 weeks in each group, but there were evidences of new growing mucosa at grafted site in 6 weeks. The remainder of the prosthesis was completely covered with glistening epithelium and the underlying fibrous tissue became more matured with little inflammation. These findings were more striking in group B than group A. 2. In group C, the covered pericardium was necrotized with stenosis of the lumen of grafted site due to poor blood supply.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.28 no.2
• /
• pp.143-153
• /
• 2006

Temporomandibular joint(TMJ) ankylosis is characterized by the formation of bony or fibrous mass, which replaces the normal articulation. Ankylotic block formation causes reduction of mandibular mobility, particularly hindering mouth opening, due to a mechanical block of the condylar head in its roto-transfatory motion. Surgery in TMJ ankylosis treatment entails complete ankylotic block removal and subsequent arthroplasty, possibly with autologous tissue between articular surfaces or heterologous material to restore the anatomic structure and normal function. Temporalis myofascial flap holds great promise for the reconstruction of various maxillofacial defects. In more recent years, a pedicled temporalis myofascial flap has been advocated in TMJ ankylosis surgery. Advantages of the temporalis myofascial flap in TMJ reconstruction include close proximity to the TMJ, adequate blood supply from the internal maxillary artery, and its attachment to the coronoid process, which provides movement of the flap during function, simulating physiologic action of the disc. This study evaluated 8 patients(11 TMJs) affected by TMJ ankylosis. All patients underwent surgical treatment of the removal of the ankylotic block and subsequent interpositional arthroplasty with temporalis myofascial flap. Bilateral TMJ ankylosis was observed in 3 patients(6 TMJs), right-sides in 3 patients, left-sided in 2 patients. Epipathogenesis was traumatic in 6 patients(8 TMJs), ankylosing spondylitis in 2 patients(3 TMJs). In 3 patients coronoidotomy was underwent. Average follow-up was 16.8 months after surgery, with a range of 7 to 28 months. No patients underwent additional TMJ procedures after the temporalis myofascial flap. All patients showed a distinctive improvement both in articular functionality and symptoms. We found that temporalis myofascial flap is very valuable in reconstruction of TMJ ankylosis.

• The Journal of Information Technology
• /
• v.4 no.2
• /
• pp.129-136
• /
• 2001

Most of the acoustic microscopes have been constructed acoustic image by simply measuring the amplitude of the reflected signal from the specimen. This method fails to produce images of good quality because the change in amplitude is not sensitive enough to specimen with fine variation. In this paper, we have been constructed the acoustic microscope system which has been able to measure simultaneously the amplitude and phase of the reflected ultrasonic signal. And also we have been constructed the amplitude and phase images for the 500 won coin as a sample and the alumium spacimen with internal round defect, and compared and analyzed these images. In expermental result, the phase image have shown better sensitive than the amplitude image and given better contrast for the micro height variation of specimen. It will be expected that the phase image can be used as an additional bit of information to improve ambiguituities in amplitude image on nondestructive testing for specimen with fine variation.