• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.473-476
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• 2005

In this paper a new type of piezoelectric floating mass type transducer (PFMT) which has advantages of the piezoelectric transducers and the electromagnetic ones has been proposed and designed. To evaluate the frequency characteristics of the PFMT, the finite element analysis and the acoustic simulation of transducer have been performed. The designed PFMT was implemented by a precision manufacturing and the vibration characteristics of the PFMT were measured. Through the measured results from various experiments, it is verified that the implemented PFMT can be used in implantable middle ear hearing devices.

• The Journal of Pediatrics of Korean Medicine
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• v.16 no.2
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• pp.39-49
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• 2002

The author measured IL-8 and $TGF-{\beta}1$ levels of 84 ears - 48 ears of them had treated by antibiotics, 36 of them by Kamihyunggyeyungyotang(KHY) - of pediatric recurrent otitis media with effusion using ELISA assay, and compared them. The results were obtained as follows. 1. The level of IL-8 in KHY group was significantly lower than that in antibiotics group(p<0.05). 2. The level of $TGF-{\beta}1$ in KHY group was lower than that in antibiotics group. According to above results, KHY is considered to be used for treating recurrent otitis media with effusion by controlling the production of interleukin-8 and transforming $growthfactor-{\beta}1$.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.136-140
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• 1997

In this paper, we proposed a implantable middle ear system using FM transmission and receiving method which has higher detection efficiency than that of AM method. And a new shape of vibrating transducer which is more efficiently vibrate than the conventional type is designed. This tranducer consist of coil and small T-type cylindrical permanent magnet. We investigated and compared the differences between conventional methods and proposed methods by quantitive analysis. We proved them by experiment.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.243-247
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• 1996

Electro-magnetic type implantable middle ear hearing aid has been empirically developed. But for further improvement of the system performance more quantitative approach is necessary. In this paper, we analyzed vibrating transducer which is most important to design the system, appropriate for given hearing level, and implemented it. Using this transducer, implantable hearing aid system are developed. To verify the design process, we experimented with driving metal strip by the developed system. From the experiment, frequency response of implemented device showed good characteristic at audio frequency and we confirmed that each part of the developed system operated well.

• Journal of Audiology & Otology
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• v.23 no.4
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• pp.204-209
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• 2019

For a minimally invasive approach to access the facial nerve, we designed an extended epitympanotomy via a transmastoid approach that has proven useful in cases of traumatic facial nerve palsy and pre-cholesteatoma. To evaluate the surgical exposure through an extended epitympanotomy, six patients with traumatic facial nerve palsy were enrolled in this study. The same surgical technique was used in all patients. Patients were assessed and the degree of facial nerve paralysis was determined prior to surgery, 1-week post-operatively, and 6-months post-operatively using the House-Brackmann grading system. In all cases, surgical exposure was adequate. All patients with traumatic facial nerve palsy were male and the age range was 13 to 83 years. In all cases, the location of the facial nerve damage was limited to the area between the first and second genu. Symptoms of all the patients improved by 6 months post-operation (p=0.024). There were no complications in any of the patients. Extended epitympanotomy is useful for safe, rapid surgical exposure of the attic area, sparing the patient post-operative dimpling, skin incision complications, and lengthy exposure to anesthesia. We suggest that surgery for patients with facial nerve palsy secondary to trauma be performed using this described technique.

• Korean Journal of Audiology
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• v.23 no.4
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• pp.204-209
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• 2019

For a minimally invasive approach to access the facial nerve, we designed an extended epitympanotomy via a transmastoid approach that has proven useful in cases of traumatic facial nerve palsy and pre-cholesteatoma. To evaluate the surgical exposure through an extended epitympanotomy, six patients with traumatic facial nerve palsy were enrolled in this study. The same surgical technique was used in all patients. Patients were assessed and the degree of facial nerve paralysis was determined prior to surgery, 1-week post-operatively, and 6-months post-operatively using the House-Brackmann grading system. In all cases, surgical exposure was adequate. All patients with traumatic facial nerve palsy were male and the age range was 13 to 83 years. In all cases, the location of the facial nerve damage was limited to the area between the first and second genu. Symptoms of all the patients improved by 6 months post-operation (p=0.024). There were no complications in any of the patients. Extended epitympanotomy is useful for safe, rapid surgical exposure of the attic area, sparing the patient post-operative dimpling, skin incision complications, and lengthy exposure to anesthesia. We suggest that surgery for patients with facial nerve palsy secondary to trauma be performed using this described technique.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.165-173
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• 2007

A differential floating mass transducer has been developed in Korea for fully implantable middle ear hearing devices (F-IMEHDs). In particular, the performance of a differential floating mass transducer (DFMT) is very important among the parts of the F-IMEHDs because the mechanical vibration generated by DFMT is delivered to the inner ear directly. In this paper, the electrical model is proposed to analyze the DFMT vibration characteristic using the mechanical model of the DFMT. The electrical model enables the simple analysis of DFMT vibration characteristics using a computer program. The proposed electrical model is simulated through PSpice as changing the values of passive elements in the electrical model. To verify the proposed model, the DFMT has been implemented on the basis of the simulated results and the experiment for vibration measurement has been carried out. Through the comparison, it is verified that the proposed model is useful to analyze the vibration characteristics of the DFMT.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.373-378
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• 2015

The structure of the human ear is divided into the outer ear, the middle ear, and the inner ear. The inner ear includes the cochlea that plays a very important role in hearing. Recently, the development of an artificial cochlear device for the hearing impaired with cochlear damage has been actively researched. Research has been carried out on the biomimetic piezoelectric thin film ABM (Artificial Basilar Membrane) in particular. In an effort to improve the frequency separation performance of the existing piezoelectric thin film ABM, this paper presents the design, fabrication, and characterization of the production and performance of a partially etched-type ABM material. $O_2$ plasma etching equipment was used to partially etch a piezoelectric thin film ABM to make it more flexible. The mechanical-behavior characterization of the manufactured partially etched-type ABM showed that the overall separation frequency range shifted to a lower frequency range more suitable for audible frequency bandwidths and it displayed an improved frequency separation performance. In addition, the maximum magnitude of the vibration displacement at the first local resonant frequency was enhanced by three times from 38 nm to 112 nm. It is expected that the newly designed, partially etched-type ABM will improve the issue of cross-talk between nearby electrodes and that the manufactured partially etched-type ABM will be utilized for next-generation ABM research.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.1-8
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• 2010

Few management studies have been conducted on late planting date for corn silage in paddy field as a barley-corn forage cropping system. Experiments were conducted during 2007 and 2008 at the Chungnam Agricultural Research & Extension Services. The objectives of this study were to determine relationships between planting date and com forage yield and to determine the best hybrid at the delayed planting after whole crop barley's harvest. The treatments consisted of 2 planting dates and 7 hybrids. Delayed planting considerately reduced stem diameter, individual ear size and weight. The ratio of dried leaf and culm in aerial plants was increased and that of ear was decreased. The coefficient of variation in fresh, dry matter (DM) and total digestible nutrients (TDN) yield was higher at delayed planting date on cropping system with whole crop barley than that of planting at optimum season. So, fresh weight was reduced by 91.8%, dry matter by 72.6%, grain yield by 51.0% and TDN yield by 68.1%. The appropriate hybrid for delayed planting after whole crop barley harvest in middle region was 'Gangdaok' as lower in the reduction of ear size and weight compared to that of planting at optimum season. Reduction in grain yield caused to decrease the DM and TDN yields. Therefore, to gain stable dry matter in silage corn by delayed planting date on cropping system with whole crop barley was necessary to select com hybrid on the minimum reduction in ear size and weight.

• Journal of Veterinary Clinics
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• v.37 no.1
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• pp.57-59
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• 2020

A 3-year-old, captive female river cooter was presented with a 4-day history of progressive unilateral swelling of the right side of the head, lethargy, and anorexia. History, physical examination, and radiographic examination revealed an aural abscess. After administration of antibiotics and supportive care, surgical intervention was performed. Swab samples were collected from the tympanic cavity during surgery for cytology and antimicrobial susceptibility testing. Molecular analyses of 16S ribosomal RNA gene sequences identified Citrobacter spp. and Morganella morganii. The patient was treated with ciprofloxacin and meloxicam and recovered after 2 months. This report describes the successful correction of a unilateral aural abscess that responded well to surgical intervention and a properly selected antibiotic.