• Korean Journal of Materials Research
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• v.5 no.6
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• pp.650-656
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• 1995

High frequency SAW filters for cellular communications were fabricated by metallizing 36$^{\circ}$Y-X LiTaO$_3$piezoelectric substrate with IIDT type electrodes. It was found that the center frequency of the filter was lowered than as designed. In order to overcome such a drawback and enable a fine tuning of its center frequency, dielectric SiN$_{x}$ thin films were deposited on LiTaO$_3$substrate by PECVD as passivation layer and then frequency responses were also characterized. As a result, the center frequency of the filter could be shifted to a higher frequency with increasing the thickness of SiN$_{x}$ film, because SAW velocity increased with increasing the ratio of the thickness of dielectric thin film to wavelength. The insertion loss of the filter, however, became larger with increasing the thickness of SiN$_{x}$ film.

• Archives of Plastic Surgery
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• v.47 no.1
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• pp.49-53
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• 2020

Background Identifying patients who may be at high risk for wound complications postsarcoma resection and reconstruction is essential for improving functional outcomes and quality of life. Currently, the effect of timing on sarcoma reconstruction has been poorly investigated. The purpose of this study was to compare outcomes of delayed and immediate reconstruction in the setting of sarcoma resection requiring flap reconstruction in the lower extremity. Methods A retrospective review of the senior author's sarcoma reconstruction patients from January 2005 to July 2017 was completed. All patients undergoing flap reconstruction of the lower extremity were included. Complications in the early postoperative period were compared between delayed and immediate reconstructive procedures. Results A total of 32 patients (7 delayed, 25 immediate) were included in this study. There was a significantly increased rate of overall complications (100% vs. 28.0%, P=0.001) and rate of hematomas (28.6% vs. 0.0%, P=0.042) in the delayed reconstruction group. Other complications including dehiscence, seroma, infection, venous thrombosis, and total/partial flap loss were also increased in the delayed reconstruction group, but this was not considered to be significant. Conclusions This study suggests that delayed reconstruction following sarcoma resection of the lower extremity had a higher incidence of overall complications and hematoma formation. We emphasize the importance of early plastic and reconstructive surgeon referral and the necessity to closely monitor delayed reconstruction patients for complications.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.381-381
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• 2010

$(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films as gate dielectrics have been proposed to overcome the problems of tunneling current and degradation mobility inachieving a thin equivalent oxide thickness. An extremely thin $SiO_2$ layer is used in order to separate the carrier in MOSFET channel from the dielectric field fluctuation caused by phonons in the dielectric which decreases the carrier mobility. The electronic and optical properties influenced the device performance to a great extent. $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric films on p-Si (100) were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gapswere obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric thin film, grown on Si substrate were about 5.34, 2.35 and 1.87 eV respectively. This band alignment was similar to that of $ZrO_2$. In addition, The dielectric function (k, $\omega$), index of refraction n and the extinction coefficient k for the $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-$\varepsilon$(k, $\omega$)-REELS software package. These optical properties are similar with $ZrO_2$ dielectric thin films.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.842-847
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• 1998

Ohmic thawing in combination with conventional water immersion thawing was investigated. Frozen meat chunks $(10{\times}10{\times}10{\;}cm)$ were immersed in a water reservoir $(12{\times}12{\times}12{\;}cm)$ which temperature was maintained at $10^{\circ}C{\;}or{\;}20^{\circ}C$, and were positioned between two stainless-steel electrodes $(10{\times}10{\;}cm)$ having no direct contact with the samples. Alternating current $(60{\;}V{\sim}210{\;}V)$ at various frequency $(60{\;}Hz{\sim}60{\;}kHz)$ was used to generate internal heat by the electrical resistance. When the frequency was fixed to 60Hz, thawing time was reduced as the voltage increased. Frequency changes gave no significant effect on thawing time. Ohmically-thawed samples treated with lower voltage showed lower drip loss and higher water holding capacity.

• Journal of Korean Neurosurgical Society
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• v.60 no.4
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• pp.456-464
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• 2017

Objective : Although little is known about its origins, neck pain may be related to several associated anatomical pathologies. We aimed to characterize the incidence and features of chronic neck pain and analyze the relationship between neck pain severity and its affecting factors. Methods : Between March 2012 and July 2013, we studied 216 patients with chronic neck pain. Initially, combined tramadol (37.5 mg) plus acetaminophen (325 mg) was administered orally twice daily (b.i.d.) to all patients over a 2-week period. After two weeks, patients were evaluated for neck pain during an outpatient clinic visit. If the numeric rating scale of the patient had not decreased to 5 or lower, a cervical medial branch block (MBB) was recommended after double-dosed previous medication trial. We classified all patients into two groups (mild vs. severe neck pain group), based on medication efficacy. Logistic regression tests were used to evaluate the factors associated with neck pain severity. Results : A total of 198 patients were included in the analyses, due to follow-up loss in 18 patients. While medication was successful in reducing pain in 68.2% patients with chronic neck pain, the remaining patients required cervical MBB. Lateral cervical curvature, such as a straight or sigmoid type curve, was found to be significantly associated with the severity of neck pain. Conclusion : We managed chronic neck pain with a simple pharmacological management protocol followed by MBB. We should keep in mind that it may be difficult to manage the patient with straight or sigmoid lateral curvature only with oral medication.

• Journal of Veterinary Clinics
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• v.33 no.6
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• pp.395-399
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• 2016

In the present case, the effect and toxicity of carboplatin and cyclophosphamide chemotherapy combined with surgery of mammary tumors in a dog were examined. An 8-year old spayed female Beagle presented with a mammary tumor. Physical examination, radiography, ultrasonography, computed tomography (CT), and laboratory examination were performed. Metastasis of the mammary tumor was confirmed by CT scan. Chemotherapy using a combination of carboplatin and cyclophosphamide was initiated following surgery. The first cycle of chemotherapy was planned to last for 6 weeks; it was planned that carboplatin would be intravenously administered for the first week (1 day) and cyclophosphamide would be intravenously administered for the next 3 weeks (22 days). Between the end of cycle 1 and the beginning of cycle 2, based on CT, it was confirmed that the number and size of tumors were unchanged and the tumors had not spread to other organs. However, at the end of cycle 2 and the beginning of cycle 3, CT revealed an increase in the number and size of mass in the lung. Chemotherapy was associated with adverse effects such as lethargy, anorexia, leukopenia, and hair loss. In conclusion, this case showed that a combination of carboplatin and cyclophosphamide suppressed the development of new neoplasms as well as metastasis for a certain period of time but did not improve the survival time. Although more cases are required, this chemotherapeutic procedure remains challenging.

• Polymer(Korea)
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• v.35 no.6
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• pp.599-604
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• 2011

The PET-PEN copolymers have been synthesized and the effect of their morphology on the physical properties of polyester flexible substrate was investigated. It was found that the block sequence of synthesized copolymer was varied depending upon DMT/NDC ratio in polymerization. Higher PET-PEN and PEN block sequence in polyester copolymer resulted in the increase of glass transition temperature and it caused the enhancement of dimensional stability as a polyester flexible substrate. The highest coefficient of thermal expansion(CTE) was obtained when DMT/NDC ratio is 50/50. Synthesized PET-PEN copolymer seems to be acceptable as a flexible substrate since it shows that their optical transmittance at 550 nm is over 80% and thermal weight loss at $280^{\circ}C$ for 1 hr is less than 0.4 wt%.

• Journal of Powder Materials
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• v.26 no.5
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• pp.432-436
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• 2019

This study demonstrates the effect of addition of Fe particles of different sizes on the critical properties of the superconductor $MgB_2$. Bulk $MgB_2$ is synthesized by ball milling Mg and B powders with Fe particles at $900^{\circ}C$. When Fe particles with size less than $10{\mu}m$ are added in $MgB_2$, they easily react with B and form the FeB phase, resulting in a reduction in the amount of the $MgB_2$ phase and deterioration of the crystallinity. Accordingly, both the critical temperature and the critical current density are significantly reduced. On the other hand, when larger Fe particles are added, the $Fe_2B$ phase forms instead of FeB due to the lower reactivity of Fe toward B. Accordingly, negligible loss of B occurs, and the critical properties are found to be similar to those of the intact $MgB_2$.

• Journal of Korean Medicine for Obesity Research
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• v.3 no.1
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• pp.49-59
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• 2003

Objectives : The purpose of this study is to evaluate the effect the of treatment in obesity clinic in east-west collaboration center, furthermore to search for how to join and improve east medicine and west medicine more closely. Methods : 37 patients were classified into four groups by Body Mass Index(BMI); normal, overweight, 1st obesity and 2nd obesity groups. Weight, BMI, body fat rate and abdominal fat rate were compared in each group by paired t-test. Results & Conclusions : In distribution of sex, male were 10(27%), female were 27(73%). Mean age was $34{\pm}13$ and the patients in twenties un the most. Among four groups, the number of End obesity groups was the most. Most patients had a preference for western medication and ear acupuncture therapy. In general we could find the correlation between the effect of obesity treatment and the degree of obesity. The more the obesity degree was, the more weight loss was.

• Journal of the Optical Society of Korea
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• v.18 no.3
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• pp.261-273
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• 2014

In this paper, metal insulator metal (MIM) plasmonic slot cavity narrow band-pass filters (NBPFs) are studied. The metal and dielectric of the structures are silver (Ag) and air, respectively. To improve the quality factor and attenuation range, two novel NBPFs based on tapered structures and double cavity systems are proposed and numerically analyzed by using the two-dimensional (2-D) finite difference time domain (FDTD) method. The impact of different parameters on the transmission spectrum is scrutinized. We have shown that increasing the cavities' lengths increases the resonance wavelength in a linear relationship, and also increases the quality factor, and simultaneously the attenuation of the wave transmitted through the cavities. Furthermore, increasing the slope of tapers of the input and output waveguides decreases attenuation of the wave transmitted through the waveguide, but simultaneously decreases the quality factor, hence there should be a trade-off between loss and quality factor. However, the idea of adding tapers to the waveguides' discontinuities of the simple structure helps us to improve the device total performance, such as quality factor for the single cavity and attenuation range for the double cavity. According to the proposed NBPFs, two, three, and four-port power splitters functioning at 1320 nm and novel ultra-compact two-wavelength and triple-wavelength demultiplexers in the range of 1300-1550 nm are proposed and the impacts of different parameters on their performances are numerically investigated. The idea of using tapered waveguides at the structure discontinuities facilitates the design of ultra-compact demultiplexers and splitters.