• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.128-129
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.152.4-152
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• 1998

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.198-201
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a SiO thin film. The homogenous alignment can be obtain어 using ion beam (IB) exposure on the SIO thin film, when positive type NLC ($Delta\varepsilon$>0) was injected However, the homeotropic alignment can be obtained using ion beam (IB) exposure on the SiO thin film, when negative type NLC ($\Delta\varepsilon$>0) was injected The LC aligning ability on the SiO thin film depends on the dielectric anisotropy type of LC. It will be discussed.

• Korean Journal of Microbiology
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• v.19 no.4
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• pp.163-173
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• 1981

The distribution of methanol-assimilating yeasts on three different sources (elm bark, soil and fresh-water mud) and the growth conditions of a new strain of Candidaboidinii (SIO) wereexamines. From 150 samples, 91 methanol yeasts were isolated through enrichment culture ; they were identified as 77 strains of Candida boidinii including four new strains, 5 isolates of Torulopsis pinus, 3 strains of Hansenula polymorpha and one sstrain of Pichia pastoris respectively. The comparison of these yeasts with three sources indicated that decaying bark of elm tree other two, and that Gandida boidinii was most frequently distributed in all three sources. Four new strains of Candida boidinii were freshly isolated and their taxonomical properties were discussed. Of them, SIO strain was selected and characterized for its growth on methanol. This yeast could grow well on less than 1%(v/v) methanol. However, its growth was inhibited at 10% methanol. The cell yield was 3.1g (dry weight) per 1000ml of mineral mediurr, containing 1%(v/v) methanol as well as 01.% yeast extract as additive. The concentration of 0.1% yeast extract appears to be effective for the biomass production. Optimum conditions for growth on methanol was found to be : $28^{\circ}C,\;NH_4^+$ as nitrogen sources, thiamine as vitamin, and pH 4.5 to 6.0. The cell composition was as follows : crude protein and nucleic acids were 54% and 7% respectively. The amino acids were also described.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.583-588
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• 1999

The characteristics of copper thin films and pattern filling capability were investigated by ECD. Prior to deposition of copper film, seed-Cu/Ta(TaN)/$SIO_2$(BPSG)/Si structure was manufactured. Copper deposition was performed with various current waveforms(DC/PC, 1~10,000Hz) and current densities(10~60 mA/$\textrm{cm}^2$) after pretreatment (Oxident removal, wetting) of seed-layer. Conformal pattern filling was performed using PC method with fast deposition rate of 6,000~8,000$\AA$/min. Heat-treated($450^{\circ}C$, 30min) copper films showed good resistivities of 1.8~2.1$\mu$$\Omega$.cm. According to the XRD analysis, (111)-preferred orientation of copper film was found in ECD-Cu/seed-Cu/Ta/$Sio_2$/Si structure. Also, we have successfully achieved to fill via holes with 0.35$\mu\textrm{m}$ width and 4:1 aspect ratio.

• Coupled systems mechanics
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• v.11 no.3
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• pp.267-284
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• 2022

Due to the high usage of ABS in industries, such as aerospace, auto, recreational devices, boat, submarines, etc., the purpose of this project was to find a way to weld this material, which gives advantages, such as affordable, high speed, and good connection quality. In this experimental project, the friction welding method was applied with parameters such as numerical control (NC) machine with two different speeds and three cross-sections, including a flat surface, cone, and step. After the end of the welding process, samples were then applied for both tensile and bending tests of materials, and the results showed that, with increasing the machining velocity Considering of samples, the friction of the surface increased and then caused to increase in the surface temperature. Considering mentioned contents, the melting temperature of composite materials increased. This can give a chance to have a better combination of Nanomaterial to base melted materials. Thus, the result showed that, with increasing the weight percentage (wt %) of Nanomaterials contents, and machining velocity, the mechanical behavior of welded area for all three types of samples were just increased. This enhancement is due to the better melting process on the welded area of different Nano contents; also, the results showed that the shape of the welding area could play a significant role, and by changing the shape, the results also changed drastically.A better shape for the welding process was dedicated to the step surface.

• Childhood Kidney Diseases
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• v.6 no.2
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• pp.209-217
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• 2002

Purpose : Corticosteroid has been used as the mainstay therapy of childhood NS. But SIO is one of the serious complications of long-term steroid therapy, especially in growing children. Recently calcium, calcitonin, PTH, vitamin D and bisphosphonate has been used to treat or prevent SIO in adult, which is rare in children with NS. We studied the effect of $1{\alpha}-(OH)D_3$ and Pamidronate on SIO using dual energy X-ray absorptiometry (DEXA). Patients and methods : We studied thirty patients who admitted in the Dept. of Pediatrics of Kyung Hee Medical Hospital with NS. All patients was received longterm steroid therapy. There was no history of bone, liver, or endocrine disease. The samples, serum protein, albumin, BUN, creatinine, calcium, phosphorus, and BMD were obtained before and the six months after the dose of $1{\alpha}-(OH)D_3$ and Pamidronate, respectively Results : The mean age was $6.9{\pm}3.3\;and\;6.5{\pm}2.5$ years old. The mean duration of steroid therapy was $28.8{\pm}1.8\;and\;27.6{\pm}1.0$ months. The changes of serum protein, albumin, BUN, creatinine, calcium and phosphorus level between pre-treatment and post-treatment did not show statistical significance in both $1{\alpha}-(OH)D_3$ and Pamidronate treatment group. However, BMD was increased in both from $0.472{\pm}0.12\;and\;0.457{\pm}0.10\;g/cm^2\;to\;0.533{\pm}0.12$ and $0.529{\pm}0.09\;g/cm^2$ after treatment. (P<0.05) Conclusion : Both $1{\alpha}-(OH)D_3$ and Pamidronate appears to be effective in treating and preventing SIO in children with nephrotic syndrome requiring long-term steroid therapy.

• Childhood Kidney Diseases
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• v.8 no.1
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• pp.43-50
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• 2004

Background : Steroid-induced osteoporosis(SIO) is one of the serious complications of long-term steroid therapy, especially in growing children. Recently bisphosphonates have been used to treat or prevent SIO in adult, which is rare in children with glomerular diseases. We studied the effect of pamidronate on SIO using dual energy X-ray absorptiometry and biochemical markers of bone turnover. Methods : Forty four children receiving moderate-to-high doses of steroids were enrolled. They had no history of bone, liver, or endocrine disease. Patients were stratified by their baseline bone mineral density(BMD) findings. All patients received corticosteroids for 3 month and oral calcium supplementation(500 mg/day) daily. Among them, 28 patients were treated with placebo and 16 were treated with pamidronate(125 mg) for 3 months. Blood chemistry and bone mineral density(BMD) were measured at baseline, and 3months. In addition, parathyroid hormone(PTH), serum osteocalcin, and urinary dipyridinoline levels were evaluated. Results : In overall population, the mean lumbar spine BMD decreased from $0.754{\pm}0.211(g/cm^2)$ to $0.728{\pm}0.208(g/cm^2)$ in the placebo group(P<0.05) and increased from $0.652{\pm}0.194(g/cm^2)$ to $0.658{\pm}0.226(g/cm^2)$ in the pamidronate group(P>0.05). Conclusion : Pamidronate appears to be effective in preventing SIO in children with glomerular diseases requiring long-term steroids therapy. Further careful observation and follow-up might be needed for children receiving bisphosphonates such as pamidronate.

• Childhood Kidney Diseases
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• v.18 no.2
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• pp.92-97
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• 2014

Purpose: Bisphosphonates are widely used for the management steroid-induced osteoporosis (SIO) in children. With the increasing use of bisphosphonates, there have been reports of abnormal radiological findings in the growing skeleton. Therefore, their use in pediatric patients remains controversial. The present study was conducted to evaluate the long-term follow-up radiographic features, particularly metaphyseal sclerotic lines, in children who receive pamidronate therapy for nephropathy. Methods: Twenty-four children with nephropathy treated with oral calcium and pamidronate (mean duration, 9 months; dose, 100 mg daily), were evaluated retrospectively. All patients had SIO secondary to chronic glucocorticoid therapy for treating nephropathy. Long bone radiographic imaging was performed before treatment with pamidronate, and at follow-up, several years later. Physeal growth rates were estimated by measuring the distance that the sclerotic lines moved on the radiographs during the corresponding time intervals. Results: The mean follow-up period was 138 months. Long bone radiographs showed well-defined sclerotic lines at the metaphyseal ends, progressively moving from the physeal plate to the diaphysis, in all patients. The mean rate of movement of the sclerotic line was 6.21 mm per year. In 12 patients, the lines disappeared. The mean rate of growth in height was 7.33 cm per year. Conclusions: Results of long-term follow-up suggest that the metaphyseal sclerotic lines associated with pamidronate treatment tend to disappear without affecting overall skeletal growth. Bisphosphonate treatment for SIO in children with nephropathy seems to be safe, although further studies in larger number of patients are needed.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.888-893
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• 1998

In practice, not only the load current but also the load voltage may contain asymmetric and harmonic components. Instantaneous power using p-q theory is analyzed to have compensation of reactive power, harmonics and asymmetry at the same time. In this paper, the limitation of p-q theory by using only shunt or series active filter is analyzed. A new scheme is proposed to solve the above issues.