• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.21 no.1
• /
• pp.70-75
• /
• 2012

The technique with ultrasonic vibration refers to the many industries. Especially Ultrasonic Connection Method is widely used for mobile battery, secondary battery, automobile components and also they recently started using it for terminal connecting of solar community battery. In this study, ultrasonic welding horn is analysed and designed with FEM, then manufactured based on it. Resonance frequency and amplitude of horn would be measured and compared with the designing result to judge the suitability. Al/Al specimen is welded by the manufactured horn and verify its performance via the weldability evaluation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.11a
• /
• pp.383-386
• /
• 2005

In this paper, proposed new partial resonance ZCS PWM controlled High frequency insulated Full-bridge DC-DC converter not using exciting current of high frequency transformer. It is compared with the existing principles in characteristics. It also realizes a widely stabilized ZVS operating using new ON-OFF control method at synchronized power rectification MOSFET of high frequency insulated transformer secondary. Besides, it is brought over 97[%] measurement efficiency by proposed DC-DC converter.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.4
• /
• pp.265-271
• /
• 2000

A non-contact battery charger for cellular phone is designed using half-bridge series resonant converter. This converter utilizes series resonance to reduce the undesirable effect of large leakage inductance of the detachable transformer and ZVS operation can reduce switching loss and switching noise. In this paper, analysis and design procedure of half-bridge series resonant converter with detachable transformer is presented. The input voltage is 85VAC∼270VAC, and the output voltage and current is 4.1V and 800mA, respectively. Furthermore, a method of calculating the secondary current of the transformer to control the battery charging current in the constant current charging mode is proposed. The performance of the charger is verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.5
• /
• pp.406-414
• /
• 2009

To cope with the high power density and low cost in switching power supply, LLC resonant converters with the two resonant tank circuits composed of resonance capacitors and two transformers are proposed in this paper. Each transformers used for the proposed resonant circuits are parallel connected in the primary and series connected in the secondary to reduce the current unbalance. The proposed LLC resonant converters are described and verified on 300W experimental prototype.

• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.237-238
• /
• 2014

A studies about HID resonanse ignition circuit. it need more than 2kV of the output voltage. then the breakdown voltage of the output capacitor must be higher, size of the capacitor must be larger, and price are higher. so were studied possible ways by resonating by distributing the secondary number of turns of the transformer, it would reduce the breakdown voltage of the output capacitor. we also studied the method can be lit at long distance, to control the resonance frequency in dependence on its parasitic capacitor that vary according to the length of the wire.

• Journal of Korean Neurosurgical Society
• /
• v.38 no.1
• /
• pp.61-64
• /
• 2005

We report a 18-year-old man, who has been taking antihypertensive medication for 1month in a local clinic, presented with a sudden onset headache followed by left blindness. He experienced palpitation and chest discomfort during physical exertion since 2years before admission, but unfortunately has been ignored. Brain CT showed intracerebral hemorrhage in the left temporoparietal area, but cerebral angiogram and magnetic resonance image revealed no vascular anomaly. He was managed conservatively, and headache and visual loss were improved over time. Subsequently, on the evaluation of hypertension, he was diagnosed as having extra-adrenal pheochromocytoma on left paraaortic area from the results of endocrinological evaluations, abdominal CT scan, and $^{131}I$-MIBG scintigraphy.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.24 no.5
• /
• pp.413-422
• /
• 2021

Intestinal lymphangiectasia is a rare disease which is causing protein-losing enteropathy. Treatment of intestinal lymphangiectasia can be a challenge for clinicians because of the lack of specific guidelines regarding pharmacological indications. We sought to introduce a diagnostic approach and suggest guidelines for treatment. After exclusion of secondary intestinal lymphangiectasia, magnetic resonance lymphangiography is a promising tool for the assessment of abnormal lymphatic lesions in primary intestinal lymphangiectasia. Determining the extent of the lesion provides direction for treatment options. Focal short-segment intestinal lymphangiectasia can be treated via intestinal resection or radiologic embolization after dietary therapy failure. Diffuse intestinal lymphangiectasia and extensive lymphangiectasia should be treated with several drugs with a full understanding of their mechanisms.

• Clinics in Shoulder and Elbow
• /
• v.26 no.3
• /
• pp.306-311
• /
• 2023

A 13-year-old male was diagnosed with a glenoid fracture following direct shoulder trauma, for which surgical treatment was considered. After referral to a center for pediatric orthopedic care, physical examination, contralateral shoulder X-ray, and detailed computed tomography examination ruled out the presence of fracture; these findings were later confirmed by magnetic resonance imaging. Normal ossification patterns in the adolescent shoulder may simulate a fracture in traumatic settings. To accurately diagnose and manage pediatric shoulder pathology, orthopedic surgeons must be aware of the normal anatomy of the growing shoulder, its secondary ossification centers, and growth plates.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.1
• /
• pp.14-19
• /
• 2000

Purpose : This study was to present the functional brain mapping of both functional magnetic resonance imaging(MRI) and transcranial magnetic stimulation(TMS) in a case of schizencephaly. Materials and methods : A 28-year-old man, who had left hemiplegia and schizencephaly in right cerebral hemisphere, was exacted with both functional MRI and TMS. Motor function of left hand was decreased whereas right hand was within normal limit. For functional MRI, gradient-echo echo planar imaging($TR/TE/{\alpha}$=1.2 sec/90 msec/90) was employed. The paradigm of motor task consisted of repetitive self-paseo hand flexion-extension exercises with 1-2 Hz periods. An image set of 10 slices was repetitively acquired with 15 seconds alternating periods of task performance and rest and total 6 cycles (three ON periods and three OFF periods) were performed. In brain mapping, TMS was performed with the round magnetic stimulator (mean diameter; 90mm). The magnetic stimulation was done with 80% of maximal output. The latency and amplitude of motor evoked potential(MEP)s were obtained from both abductor pollicis brevis(APB) muscles. Results : Functional MRI revealed activation of the left primary motor cortex with flexion-extension exercises of healthy right hand. On the other hand, the left primary motor cortex, left supplementary motor cortex, and left promoter areas were activated with flexion-extension exercises of left hand. In TMS, magnetic evoked potentials were induced in no areas of right cerebral hemisphere, but in 5 areas of left corebral hemisphere from both abductor pollicis brevis. Latency, amplitude, and contour of response of the magnetic evoked potentials in both hands were similar. Conclusion : Functional MRI and TMS in a patient with schizencephaly were successfully used to localize cortical motor function. Ipsilateral motor pathway is thought to be secondary to reinforcement of the corticospinal tract of the ipsilateral motor cortex.

• Polymer(Korea)
• /
• v.36 no.6
• /
• pp.822-830
• /
• 2012

We used dipodal type bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to modify silica nanoparticles to introduce secondary amino groups on the silica surface. These N-H groups were reacted with three different molecular weights (M.W. = 258, 575, and 700) of poly(ethylene glycol) diacrylates to introduce different attached layer thicknesses on the silica surface by Michael addition reaction. After Michael addition reaction, we used several analytical techniques such as fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state $^{13}C$ cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy to characterize introduced structures. We found almost complete Michael addition reaction of both two acrylate groups of PDGDA with N-H groups of BTMA modified silica to form ${\beta}$-amino acid esters. Between equimolar ratio of pure BTMA and pure PEGDA reaction, only one acrylate group of two acrylate groups of PEGDA reacted with N-H groups of pure BTMA to form ${\beta}$-amino acid ester and the other remaining acrylate group can be used to form a polymer later.