• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.40-47
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• 2014

In this paper, $Al_2O_3$ film deposited by thermal atomic layer deposition (ALD) with diluted $NH_4OH$ instead of $H_2O$ was suggested for passivation layer and anti-reflection (AR) coating of the p-type crystalline Si (c-Si) solar cell application. It was confirmed that the deposition rate and refractive index of $Al_2O_3$ film was proportional to the $NH_4OH$ concentration. $Al_2O_3$ film deposited with 5 % $NH_4OH$ has the greatest negative fixed oxide charge density ($Q_f$), which can be explained by aluminum vacancies ($V_{Al}$) or oxygen interstitials ($O_i$) under O-rich condition. $Al_2O_3$ film deposited with $NH_4OH$ 5 % condition also shows lower interface trap density ($D_{it}$) distribution than those of other conditions. At $NH_4OH$ 5 % condition, moreover, $Al_2O_3$ film shows the highest excess carrier lifetime (${\tau}_{PCD}$) and the lowest surface recombination velocity ($S_{eff}$), which are linked with its passivation properties. The proposed $Al_2O_3$ film deposited with diluted $NH_4OH$ is very promising for passivation layer and AR coating of the p-type c-Si solar cell.

• Clinical and Experimental Pediatrics
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• v.48 no.5
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• pp.488-494
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• 2005

Purpose : To outline the aspects of extubation by birth weight and find the predictors for success/failure at the first extubation in extremely low birth weight infants. Methods : One hundred thirteen extremely low birth weight infants(<1,000 g) who were admitted to NICU at Samsung Seoul Hospital between Jan. 2000 and Jun. 2004 were enrolled. Clinical characteristics that are thought to be related with extubation success or failure were compared with the success and the failure of the first extubation. Results : As the birth weight decreased, extubation success day was significantly delayed : $16{\pm}3day(d)$ in 900-999 g; $20{\pm}3d$ in 800-899 g; $35{\pm}4d$ in 700-799 g; $37{\pm}9d$ in 600-699 g; $49{\pm}12d$ in ${\leq}599g$. 25 out of 113 infants(22%) failed the first extubation. Preterm premature rupture of membrane was associated with extubation success, and air leak was associated with extubation failure, with a borderline significance. Postnatal and corrected age and body weight at the first extubation, nutritional status, and ventilator settings were not associated with extubation success or failure. Extubation success day was significantly delayed, and the incidence of late-onset sepsis and mortality was significant higher in the failure of the first extubation. Conclusion : We could not find significant predictors for success/failure at the first extubation. The failure of the first extubation had an increased risk of late-onset sepsis and death. Further studies are needed to find the predictors for extubation success/failure.

• Korean Journal of Agricultural Science
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• v.18 no.1
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• pp.1-9
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• 1991

This experiment was aimed to develop possible methods to control the maturity of grape berries through the application of exogenous plant growth substances and physical treatments such as defoliation or girdling. 1. Chlormequat and paclobutrazol increased anthocyanin but did not affect soluble solids contents and maturity. Girdling enhanced maturation and solids accumulation whereas defoliation delayed maturity. Solids content of berries in defoliation treatment did not reach to the level of other treatments even when fully ripened. 2. Ripening of grapes is greatly delayed for 20 to 30 days by the application of auxins (2,4-D and fenoprop) compared to the untreated control. Uneven ripening of berries in those clusters was observed when the concentration of auxin was over 50 ppm. Thus, about 30% of berries remained green until the normal berries were overripened. 3. Gibberellin did not affect the maturity of grape berries but maturity was greatly delayed when GA was applied with auxins. Also, uneven coloration between berries was observed such as in the application of auxin alone. 4. Ethephon application combinded with calcium at veraison showed no effect on berry ripening but increased anthocaynin contents. It can be concluded that harvest time of 'Campbell Early' grapes can be effectively extended by delaying the maturity through the application of auxin.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.4
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• pp.95-115
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• 2013

Objectives The aim of this review is to provide fundamental data for low back pain scales which can be used in clinical trial. Methods We investigated the latest studies on chronic low back pain via PubMed. And we also investigated domestic studies through "http://oasis.kiom.re.kr". 95 research papers were analyzed. Scales were classified into pain scale, function scale, generic health status scale and psychological scale. Results 1) According to foreign clinical studies, Visual Analog Scale (VAS) and Numerical Rating Scale (NRS) were used 18 times as pain scale. Oswestry Disability Index (ODI) was used 20 times as function scale, Roland-Morris Disability Questionnaire (RMDQ) was 17, and Hannover Functional Ability Questionnaire (HFAQ) was used 3 times. 36-item Short Form Health Survey (SF-36) was used 13 times as generic health status scale, Euroqol-5 Dimentions Questionnaire (EQ-5D) was 11, and 12-item Short Form Health Survey (SF-12) was used 3 times. Fear-Avoidance Beliefs Questionnaire (FABQ) was used 9 times as psychological scale, Pain Catastrophizing Scale (PCS) and Tampa Scale for Kinesiophobia (TSK-R) both were used 3 times. 2) According to domestic clinical studies, VAS was used 37 times as pain scale, NRS was 11, and Short Form McGill Pain Questionnaire (SF-MPQ) was used 6 times. ODI was used 30 times as function scale, RMDQ was 2 times only. SF-36 was used once as generic health status scale and Beck's Depression Inventory (BDI) was used 3 times as psychological scale. Conclusions We recommend VAS or NRS as a measure to evaluate pain, and ODI as a measure to evaluate functional disability. And we also recommend SF-36 or SF-12 and EQ-5D as a measure to evaluate generic health status. Finally, we recommend FABQ for use in measuring psychological scale.

• Journal of Korean Society of Transportation
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• v.22 no.1 s.72
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• pp.43-62
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• 2004

Conventionally the estimation method of the origin-destination Matrix has been developed by implementing the expansion of sampled data obtained from roadside interview and household travel survey. In the survey process, the bigger the sample size is, the higher the level of limitation, due to taking time for an error test for a cost and a time. Estimating the O-D matrix from observed traffic count data has been applied as methods of over-coming this limitation, and a gradient model is known as one of the most popular techniques. However, in case of the gradient model, although it may be capable of minimizing the error between the observed and estimated traffic volumes, a prior O-D matrix structure cannot maintained exactly. That is to say, unwanted changes may be occurred. For this reason, this study adopts a conjugate gradient algorithm to take into account two factors: estimation of the O-D matrix from the conjugate gradient algorithm while reflecting the prior O-D matrix structure maintained. This development of the O-D matrix estimation model is to minimize the error between observed and estimated traffic volumes. This study validates the model using the simple network, and then applies it to a large scale network. There are several findings through the tests. First, as the consequence of consistency, it is apparent that the upper level of this model plays a key role by the internal relationship with lower level. Secondly, as the respect of estimation precision, the estimation error is lied within the tolerance interval. Furthermore, the structure of the estimated O-D matrix has not changed too much, and even still has conserved some attributes.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.213-221
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• 1990

We have experienced 62 cases of modified Fontan operations in Seoul Nat’l University Hospital from Apr. 1986 to Jul. 1989, They were 38 males and 24 females, and their age was ranged from 16 months to 15.5 years of age. [mean age : 5.73$\pm$2.99 years] There were 16 operative deaths and 2 late deaths, therefore 29% of overall mortality. Their diagnoses were as follows; 28 single ventricle, 11 tricuspid atresia, 6 DORV with LV hypoplasia, 3 pulmonary atresia with hypoplastic RV, 3 TGA with hypoplastic RV, 3 cor\ulcornerGA with hypoplastic LV and PA, 6 AV canal defects with PA, and 2 others. Low cardiac output and pleural effusion were developed frequently, so we divide 40 patients into some groups to analyze the physiologic and anatomic causes of them. By the degree of the LCO, group A was no LCO[mean amount of inotropics used: 0-5 \ulcornerg/kg/min] with 17 cases, B mild LCO [5-10] with 11, C moderate to severe LCO but alive[>10] with 8, D severe LCO to death with 4 cases. For the pleural effusion, group 1 was to be removed the chest tube within 1 week with 8 cases, group II within 3 weeks with 21 cases, group III beyond 3 weeks with 12 cases. We considered their age, diagnosis, pulmonary artery size[PA index], pulmonary artery abnormality, palliative shunt, systemic ventricular type, pulmonary artery wedge pressure, as preoperative factors, and operative methods, and as postoperative factors, CVP, LAP, arrhythmia, thrombosis, atrioventricular valvular insufficiency, etc. In the view of LCO, pulmonary artery size and PCWP were statistically significant [P<0.05], and arrhythmia, A-V valve insufficiency were inclined to the group C and D Pleural effusion was influenced by the pulmonary artery size, pulmonary artery resistance, PCWP, and CVP significantly. [P<0.05] And arrhythmia, residual shunt, and A-V valvular insufficiency were inclined to group II and III, too. As a results, the followings are to be reminded as the important factors at the care of post-Fontan LCO, and persistent pleural effusion [1] pulmonary artery size, [2] pulmonary artery resistance, [3] PCWP, [4] CVP, [5] arrhythmia, [6] residual shunt, [7]A-V valvular insufficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11A
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• pp.1104-1109
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• 2005

In this paper, a Ka-band harmonic mixer is designed and fabricated on the base of the multiplier theory that there is a bias point to maximize the third harmonic order($3f_{LO}$) with respect to a fundamental LO frequency($f_{LO}$), which can make the high-order mixing element($f_{RF}{\pm}3f_{LO}$) to be greater than other mixing elements, Pumping a RF frequency($f_{RF}$) and LO frequency($f_{LO}$). The harmonic mixer by the proposed design method is fabricated by using a commercial GaAs MESFET device with a plastic package and overcome these disadvantages that a conventional mixer in Ka-band suffer from a high cost, inefficient productivity and circuit complexity. The harmonic mixer have a -10 dB conversion loss at the IF Sequency($3f_{LO}-f_{RF}$=1.0GHz) by selecting a gate bias voltage for the maximum third-order LO harmonic element($3f_{LO}$=34.5 GHz) as pumping LO frequency($f_{LO}$=11.5 GHz) With respect to RF Sequency ($f_{RF}$=33.5GHz)

• Journal of Adhesion and Interface
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• v.13 no.2
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• pp.58-63
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• 2012

CFRP chip is the byproduct from carbon fiber reinforced plastic (CFRP) processing. CFRP chip is not simply a waste mainly composed of fine carbon fiber and epoxy resin. CFRP chip keeps matrix to maximize their reinforcing effect. To obtain a uniform length of carbon fiber in CFRP chip, chip was chopped ina mortar. CFRP chip should be purified to get better interface adhesion. Epoxy resin on the carbon fiber was removed by $H_2O_2$ surface etching treatment. Optimal dispersion and fabrication conditions of CFRP chip embedded in phenolic resin were determined by thermal stability for fire retardant applications. CFRP chip-phenolic composite exhibits better mechanical and thermal properties than neat phenolic resin. Surface condition of CFRP chip-phenolic composite was evaluated by static contact angle measurement. Contact angle of CFRP chip-phenolic composite was greater than neat phenolic due to heterogeneous condition of fine carbon fibers. From the evaluation for fire retardant (ASTM D635-06) test, thermal stability of CFRP chip-phenolic composite was found to be improved with higher concentration of CFRP chip.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.107-117
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• 2008

Private financing is playing an increasing role in public infrastructure construction projects worldwide. However, private investors/operators are exposed to the financial risk of low profitability due to the inaccurate estimation of facility demand, operation income, maintenance costs, etc. From the operator's perspective, a sound and thorough financial feasibility study is required to establish the appropriate capital structure of a project. Operators tend to reduce the equity amount to minimize the level of risk exposure, while creditors persist to raise it, in an attempt to secure a sufficient level of financial involvement from the operators. Therefore, it is important for creditors and operators to reach an agreement for a balanced capital structure that synthetically considers both profitability and repayment capacity. This paper presents an optimal capital structure model for successful private infrastructure investment. This model finds the optimized point where the profitability is balanced with the repayment capacity, with the use of the concept of utility function and multi-objective GA (Generic Algorithm)-based optimization. A case study is presented to show the validity of the model and its verification. The research conclusions provide a proper capital structure for privately-financed infrastructure projects through a proposed multi-objective model.

• Journal of Biomedical Engineering Research
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• v.37 no.1
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• pp.7-14
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• 2016

Radiopharmaceutical agents for positron emission tomography (PET), such as $^{18}F$-FDG and $^{68}Ga$, have been used not only for whole-body PET imaging but also for intraoperative radionuclide-guided surgery due to their quantitative and sensitive imaging characteristics. Current intraoperative probes detect gamma or beta particles, but not both of them. Gamma probes have low sensitivities since a collimator has to be used to reduce backgrounds. Positron probes have a high tumor-to-background ratio, but they have a 1-2 mm depth limitation from the body surface. Most of current intraoperative probes produce only audible sounds proportional to count rates without providing tumor images. This research aims to detect both positrons and annihilation photons from $^{18}F$ using plastic scintillators and a GAGG scintillation crystal attached to silicon photomultiplier (SiPM). The depth-of-interaction (DOI) along the plastic scintillator can be used to obtain the 2-D images of tumors near the body surface. The front and rear part of the intraoperative probe consists of $4{\times}1$ plastic scintillators ($2.9{\times}2.0{\times}12.0mm^3$) for positron detection and a Ce:GAGG scintillation crystal ($12.0{\times}12.0{\times}9.0mm^3$) for annihilation photon detection, respectively. The DOI resolution of $4.4{\pm}1.6mm$ along the plastic scintillator was obtained by using the 3M enhanced specular reflector (ESR) with rectangular holes between the plastic scintillators, which showed the feasibility of a 2-D image pixel size of $2.9{\times}4.4mm^2$ (X-direction ${\times}$ Y-direction).