• Macromolecular Research
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• v.11 no.5
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• pp.297-302
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• 2003

The imidization and cure reaction of a thermosetting phenylethynyl-terminated amic acid (LaRC PETI-5) in film form have been monitored as a function of temperature by means of a steady-state fluorescence technique using a front-face illumination method. The variation of the fluorescence emission spectra of LaRC PETI-5 can be divided into four temperature regions; Region I: below 15$0^{\circ}C$, Region II: 150-25$0^{\circ}C$, Region III: 250-35$0^{\circ}C$, and Region IV: above 35$0^{\circ}C$. The fluorescence spectra in Region I are largely influenced by residual N-methyl-2pyrrolidinone in the polymer and also slightly by partial imidization of the polymer. There is a combined effect of imidization and solvent removal on the fluorescence behavior in Region II. The spectra in Regions III and IV are due significantly to the cure reaction of LaRC PETI-5 and to a post-cure effect of the polyimide, respectively. This spectroscopic evidence indicating the transformation of the amic acid imide oligomer into the corresponding polyimide via imidization and cure, agrees well with thermal analysis results obtained previously. The intermediate stage of cure in the range of 250-30$0^{\circ}C$ predominantly influences the change of the fluorescence intensity. The later stage above 30$0^{\circ}C$ significantly influences the position of the spectrum. This fluorescence study also supports the mechanism proposed in earlier work that the crosslinking reaction takes place at the reaction sites in the conjugated polyene and the phenylethynyl end group in the polyimide chain.

• Journal of Korean Foot and Ankle Society
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• v.6 no.2
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• pp.161-166
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• 2002

Purpose: To evaluate the effectiveness of distraction arthroplasty as treatment for moderate or severe ankle osteoarthritis Materials and Methods: Thirteen patients who underwent distraction arthroplasty using the Ilizarov external fixator were available. We removed osteophytes around the ankle before applying the external fixator. We encourage the patients to do active range of motion exercise and to walk with cruch. Follow-up averaged 15 months (range, 10-31 months). Both the patients' postoperative satisfaction and the radiographic joint space were retrospectively evaluated. Results: The duration from applying the external fixator to remove was 12 weeks. Breakage of the wire applied to the forefoot occurred in 2 cases. All patients satisfied with the postoperative clinical results. The ankle joint space averaged $1.6{\pm}0.2mm$ in pre-operative, $4.2{\pm}0.9mm$ in post-Ilizarov external fixator's removal, and $2.3{\pm}0.3mm$ in last follow-up ankle lateral view. Conclusion: We think that distraction arthroplasty with external fixator is useful operative method for the moderate or severe ankle osteoarthritis.

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.3
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• pp.189-193
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• 2018

A 57-year-old woman scheduled for cochlear implant removal exhibited preoperative electrocardiographic findings of early repolarization (ER). Four episodes of transient ST segment elevations during surgery raised suspicion for vasospastic angina (VA). In the post-anesthetic care unit, the patient complained of chest discomfort and received sublingual nitroglycerin with uncertain effect. The patient refused to proceed with postoperative invasive coronary angiography, resulting in inconclusive diagnosis. Intraoperative circumstances limit the diagnosis of VA, which emphasizes the need for further testing to confirm the diagnosis. When VA is suspected in patients with underlying ER, it is reasonable to consider invasive examination to establish the diagnosis and prevent recurrence of VA. If ST changes are observed during surgery in patients with preoperative ER, careful monitoring is recommended. Due to general anesthesia, the absence of patient symptoms limits the definitive diagnosis of those with suspected VA. Therefore, additional postoperative surveillance is recommended.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.347-352
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• 2006

Narrowband interference can severely degrade the performance of GPS receivers. Detecting the presence of interference and then characterizing it can lead to its removal. Receivers can be reconfigured to focus on other signals or satellites that are less vulnerable to that interference at that moment. Using hardware reconfigurability of FPGA receivers and characterizing the effect of narrowband interference on the GNSS signal quality lead us to a new RFI mitigation technique in which the highest quality and less vulnerable signal can be chosen at each moment. In the previous work [1], the post processing capability of a software GPS receiver, has been used to detect and characterize the CW interference. This is achieved by passing the GPS signal and the interference through the correlator. Then, using the conventional definition of C/No as the squared mean of the correlator output divided by its variance, the actual C/No for each satellite is calculated. In this work, first the 'Exclusion zone' for each satellite signal has been defined and then by using some experiments the effects of different parameters like signal power, jamming power and the environmental noise power on the Exclusion zone have been analyzed. By monitoring the Doppler frequency of each satellite and using the actual C/No of each satellite using the traditional definition of C/No and actual data from a software GPS receiver, the decision to reconfigure the receiver to other signal can be made.

• Journal of Chest Surgery
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• v.27 no.6
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• pp.460-471
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• 1994

Between Feb. 1990 and Aug. 1993, 180 cases of the open heart surgery were performed under cardiopulmonary bypass in the Department of Thoracic & Cardiovascular surgery, Gil General Hospital. There were 83 cases with congenital heart diseases [CHD] and 97 cases with acquired heart diseases [AHD]. The CHD consisted of 78 acyanotic[mortality: 3.8 %] and 5 cyanotic cases with heart anomaly[mortality:l case]. The AHD were 97 cases, which contained 53 valvular, 27 ischemic heart diseases, 10 aortic diseases, 5 cases with myxoma, 1 case with post-infarct VSD, and 1 case with removal of infected pacing wire in right ventricle. In the 53 valvular heart diseases, there were 45 cases with valve replacement[MVR 27, AVR 9,MVR + AVR 9] and 8 cases with valvuloplasty. The number of the implanted prosthetic valves were 53. In MVR, 25 St. Jude, 6 Sorin, 3 Carpentier-Edward and 2 Intact medical valves were used. In aortic position, 13 St. Jude, 3 Sorin and 1 Intact medical valves were applied. The operative mortality was 5.6 % [3/53]. The annuloplasty applying artificial ring was performed in 17 patients[4 cases associated with MVR] and the number of the implanted ring was 19, which included 14 Duran ring[10 mitral, 4 tricuspid] and 5 Carpentier ring [3 mitral, 22 tricuspid]. In the 27 ischemic heart diseases, there were 9 cases with left main coronary artery lesions, 7 one vessel, 5 two vessels, and 6 three vessels. Average number of anastomosis was 2.8 per patient. The operative mortality was 14.3 % [4/27]. Among the 10 patients with aortic diseases, 7 cases were aortic dissection[type A: 5, type B: 2] and 3 cases were descending thoracic aortic aneurysm. The operative morality occurred in 3 cases. The overall mortality and the operative mortality of congenital and acquired heart disease was 7.8 %, 4.8% and 10.4%, respectively.

• Journal of Korean Society on Water Environment
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• v.34 no.4
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• pp.382-390
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• 2018

In this study, the LIDMOD3 was developed to design and evaluate low impact development (LIDMOD). In the same fashion, the LIDMOD3 employs a curve number (NRCS-CN) method to estimate the surface runoff, infiltration and event mean concentration as applicable to pollutant loads which are based on a daily time step. In these terms, the LIDMOD3 can consider a hydrologic soil group for each land use type LID-BMP, and the applied removal efficiency of the surface runoff and pollutant loads by virtue of the stored capacity, which was calculated by analyzing the recorded water balance. As a result of Model development, the LIDMOD3 is based on an Excel spread sheet and consists of 8 sheets of information data, including: General information, Annual precipitation, Land use, Drainage area, LID-BMPs, Cals-cap, Parameters, and the Results. In addition, the LIDMOD3 can estimate the annual hydrology and annual pollutant loads including surface runoff and infiltration, the LID efficiency of the estimated surface runoff for a design rainfall event, and an analysis of the peak flow and time to peak using a unit hydrolograph for pre-development, post-development without LID, and as calculated with LID. As a result of the model application as applied to an apartment, the LIDMOD3 can estimate LID-BMPs considering a well spatical distributed hydroloic soil group as realized on land use and with the LID-BMPs. Essentially, the LIDMOD3 is a screen level and simple model which is easy to use because it is an Excel based model, as are most parameters in the database. This system can be expected to be widely used at the LID site to collect data within various programmable model parameters for the processing of a detail LID model simulation.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.308-313
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• 1997

Ceftriaxone, an effective third generation cephalosporin with a wide range of antimicrobial activity, has become widely used by pediatricians for a variety of bacterial infections including meningitis. It has been associated with the development of sludge or stone in the gallbladder of some patients treated with this drug. Ceftriaxone associated biliary sludge has unusual acoustic characteristics and resembles gallstone. The sludge can cause symptoms such as cramping abdominal pain, and disappears after stopping ceftriaxone administration. Because of these seemingly confusing observations, it is important for the clinicians to recognize these findings that ceftriaxone treatment can cause. We report a case of ceftriaxone associated biliary sludge in Korean children. A 6-year-old girl who was treated for meningitis with ceftriaxone (100mg/kg/day) developed cramping upper abdominal pain from 5th hospital day. Physical examination, liver function tests and X-ray revealed no specific abnormal findings. But abdominal ultrasound revealed high amplitude echogenic sludge with prominent post-acoustic shadow in gallbladder and its diameter was 1.5cm. We stopped ceftriaxone administration and tried conservative care. Abdominal cramping pain subsided after 3 days of ceftriaxone removal. Second abdominal ultrasound confirmed the disappearance of sludge at 3 weeks later.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.1
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• pp.11-15
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• 2007

Background and Objectives: $VoCoM^{(R)}$ is a set composed of prefabricated hydroxylapatite implants and shims of various sizes that are designed for the type I thyroplasty, Authors aimed to evaluate the efficacy of $VoCoM^{(R)}$ System in type I thyroplasty. Materials and Method: Twenty three patients with unilateral vocal cord palsy were included in the study, who received type I thyroplasty with $VoCoM^{(R)}$ between May 2000 and May 2007 in St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea, Acoustic, aerodynamic and stroboscopic analyses were performed pre-and post-operatively, Subjective voice improvement was analysed by Voice handicap index, Results : Preoperative jitter was $4.68{\pm}2.46%$ and improved to $3.19{\pm}1.94%$(P<0,05), Preoperative NHR was $0.26{\pm}0.1$ and improved to $0.18{\pm}0,07$(P<0.05), Preoperative MPT was $6.16{\pm}4.9$secs improved to $9.55{\pm}4.67$secs(p<0.05), The postoperative stroboscopy revealed an effective medialization of vocal fold of all patients, Conclusion: Type I thyroplasty using $VoCoM^{(R)}$ is a efficient, safe and convenient way of vocal fold medialization at the expense of its high cost and difficulty in removal.

• Journal of Menopausal Medicine
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• v.24 no.3
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• pp.163-168
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• 2018

Objectives: To investigate the rate of postoperative urinary retention (POUR) and identify the risk factors for this complication in women who underwent transvaginal uterosacral suspension surgery. Methods: A retrospective chart review was conducted for 75 women who underwent transvaginal uterosacral suspension surgery with vaginal hysterectomy, repair of cystocele, and levator myorrhaphy with/without transobturator anti-incontinence surgery. POUR was defined as a need for continuous intermittent catheterization on the third day subsequent to removal of the urethral indwelling catheter. Results: Acute POUR was reported in 18 women (24.0%). Thirty-six of the 75 patients (48.0%) had undergone anti-incontinence surgery. Crude analysis revealed significant association between the following variables and the risk of POUR: hypertension, the lower average flow rate in the pressure-flow study (PFS), greater post-void residual (PVR) urine volume in PFS, and PVR >30% of the total bladder capacity (TBC) in PFS. In the logistic regression analysis, PVR >30% of the TBC in PFS was identified as the only significant predictor of POUR (odds ratio, 15.4; 95% confidence interval, 2.5-90.9; P = 0.003). Conclusions: The PVR >30% of the TBC in PFS was identified as the only predictive factor of acute POUR in women who underwent transvaginal uterosacral suspension surgery.

• Tribology and Lubricants
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• v.35 no.5
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• pp.274-285
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• 2019

Chemical mechanical polishing (CMP), which is a material removal process involving chemical surface reactions and mechanical abrasive action, is an essential manufacturing process for obtaining high-quality semiconductor surfaces with ultrahigh precision features. Recent rapid growth in the industries of digital devices and semiconductors has accelerated the demands for processing of various substrate and film materials. In addition, to solve many issues and challenges related to high integration such as micro-defects, non-uniformity, and post-process cleaning, it has become increasingly necessary to approach and understand the processing mechanisms for various substrate materials and abrasive particle behaviors from a tribological point of view. Based on these backgrounds, we review recent CMP R&D trends in this study. We examine experimental and analytical studies with a focus on substrate materials and abrasive particles. For the reduction of micro-scratch generation, understanding the correlation between friction and the generation mechanism by abrasive particle behaviors is critical. Furthermore, the contact stiffness at the wafer-particle (slurry)-pad interface should be carefully considered. Regarding substrate materials, recent research trends and technologies have been introduced that focus on sapphire (${\alpha}$-alumina, $Al_2O_3$), silicon carbide (SiC), and gallium nitride (GaN), which are used for organic light emitting devices. High-speed processing technology that does not generate surface defects should be developed for low-cost production of various substrates. For this purpose, effective methods for reducing and removing surface residues and deformed layers should be explored through tribological approaches. Finally, we present future challenges and issues related to the CMP process from a tribological perspective.