• Childhood Kidney Diseases
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• v.26 no.1
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• pp.40-45
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• 2022

Purpose: Chronic kidney disease (CKD) has various underlying causes in children. Identification of the underlying causes of CKD is important. Genetic causes comprise a significant proportion of pediatric CKD cases. Methods: In this study, we performed whole-exome sequencing (WES) to identify genetic causes of pediatric CKD. From January to June 2021, WES was performed using samples from pediatric patients with CKD of unclear etiology. Results: Genetic causes were investigated using WES in 37 patients (17 males) with pediatric CKD stages 1 (n=5), 2 (n=7), 3 (n=2), 4 (n=2), and 5 (n=21). The underlying diseases were focal segmental glomerulosclerosis (n=9), congenital anomalies of the kidney and urinary tract including reflux nephropathy (n=8), other glomerulopathies (n=7), unknown etiology (n=6), and others (n=7). WES identified genetic causes of CKD in 12 of the 37 patients (32.4%). Genetic defects were discovered in the COL4A4 (n=2), WT1 (n=2), ACTN4, CEP290, COL4A3, CUBN, GATA3, LAMA5, NUP107, and PAX2 genes. WT1 defects were found in patients whose pathologic diagnosis was membranoproliferative glomerulonephritis, and identification of CUBN defects led to discontinuation of immunosuppressive agents. Genetic diagnosis confirmed the clinical diagnosis of hypoparathyroidism, sensorineural deafness, and renal disease; Alport syndrome; and Joubert syndrome in three of the patients with CKD of unknown etiology (COL4A4 [n=2], CUBN [n=1]). Extrarenal symptoms were considered phenotypic presentations of WT1, PAX2, and CEP290 defects. Conclusions: WES provided a genetic diagnosis that confirmed the clinical diagnosis in a significant proportion (32.4%) of patients with pediatric CKD.

• Korean Journal of Materials Research
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• v.8 no.1
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• pp.27-32
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• 1998

In-Sit반응소결에의해 Si과 AI금속분말을 이용하여 Si$_{3}$N$_{4}$-AIN 복합세라믹스를 합성하였다. 합성된 Si$_{3}$N$_{4}$-AIN복합세라믹스의 미세조직과 결정구조를 해석하기 위해, OM, TEM, XRD및 EDX를 이용하였으며, Si$_{3}$N$_{4}$-AIN -20wt.%AIN복합세라믹스에서 Si의 질화율은 97%로 가장 높았다. Si$_{3}$N$_{4}$-AIN 복합세라믹스에서 Si의 질화율은 AI첨가량 증가에 따라 감소하였다. 대부분의 AI입자들은 다결정 AI입자들은 다결정 AIN(4-H구조)로 완전질화되었으며, 따라서 잔류 AI상은 반응소결체내에서 관찰되지 않았다. Si$_{3}$N$_{4}$의 결정구조는 $\alpha$와 $\beta$구조가 혼재된 상태이며, 잔류 Si입자내에서는 미소균열 및 전위가 관찰되었다. AI/Si$_{3}$N$_{4}$와 Si$_{3}$N$_{4}$ 두계면에서 이들은 거친 형상을 보이지만, 계면반응상은 관찰되지 않았다.

• Advances in materials Research
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• v.5 no.3
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• pp.131-140
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• 2016

Copper/silicon nitride ($Cu/Si_3N_4$) composites are fabricated by powder technology process. Copper is used as metal matrix and very fine $Si_3N_4$ particles (less than 1 micron) as reinforcement material. The investigated powder were used to prepare homogenous ($Cu/Si_3N_4$) composite mixtures with different $Si_3N_4$ weight percentage (2, 4, 6, 8 and10). The produced mixtures were cold pressed and sintered at different temperatures (850, 950, 1000, $1050^{\circ}C$). The microstructure and the chemical composition of the produced $Cu/Si_3N_4$ composites were investigated by (SEM) and XRD. It was observed that the $Si_3N_4$ particles were homogeneously distributed in the Cu matrix. The density, electrical conductivity and coefficient of thermal expansion of the produced $Cu/Si_3N_4$ composites were measured. The relative green density, sintered density, electrical conductivity as well as coefficient of thermal expansion were decreased by increasing the reinforcement phase ($Si_3N_4$) content in the copper matrix. It is also founded that the sintered density and electrical conductivity of the $Cu/Si_3N_4$ composites were increased by increase the sintering temperature.

• Korean Journal of Environmental Agriculture
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• v.15 no.3
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• pp.348-354
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• 1996

This study was carried out to investigate factors influencing on the groundwater quality at controlled horticulture in Honam area in 1995. The deeper groundwater sampling, the lower concentrations of $NH_4-N$ and $NO_3-N$ were observed. There was no difference in concentrations of $SO_4\;^{2-}$ and $Na^+$ in the groundwater below 15m. Contents of $NH_4-N$, $NO_3-N$ and $PO_4\;^{3-}$ in groundwater were the highest at rice transplanting season(the late May) and that of $SO_4\;^{2-}$, $Na^+$ and $Cl^-$ were the highest at dry season(the mid-February). Continuous cultivation of horticultural crops showed higher concentration of $NH_4-N$, $NO_3-N$, $PO_4\;^{3-}$, $Na^+$ and $Cl^-$ in groundwater than rotational culture with rice. The longer cultivation years with horticultural crops, the higher concentrations of $NO_3-N$, $PO_4\;^{3-}$, $SO_4\;^{2-}$ and $Cl^-$ were shown, and constitutional ratio of $NO_3-N$ among the anions increased gradually. Nitrate-N level, exceeded 20mg/l, the critical level for agricultural usage, frequently at Yongjinmyeon Wanju and Janglockdong Kwangju, and $PO_4\;^{3-}$ levels were higher at Seogtandong Iksan than the other places.

• Journal of the Korean Ceramic Society
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• v.24 no.1
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• pp.23-32
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• 1987

Synthesis of high purity ultrafine Si3N4 and ${\beta}$-Sialon powders was investigated via the simultaneous reduction and nitriding of amorphous SiO2, SiO2-Al2O3 system prepaerd by hydrolysis of alkoxides, using carbonablack as a reducing agent. In Si(OC2H5)4-C2H5 OH-H2 O-NH4OH system, hydrolysis rate increased with increasing reaction temperature and pH. Pure ${\alpha}$-Si3N4 was formed at 1350$^{\circ}C$ for 5 hrs in N2 atmosphere. In Si(OC2H5)4-Al(OC3H7)3-C6H6-H2 O-NH4OH system, weight loss increased as Si/Al ratio decreased. Single phase ${\beta}$-Sialon consisted of Si/Al=2 was formed at 1350$^{\circ}C$ in N2 and minor phases of ${\alpha}$-Si3N4, AIN, and X-phase were existed besides theSialon phase at other Si/Al ratios. The Si3N4 and Sialon powders synthesized from alkoxides consisted of uniform find particles of 0.05-0.2$\mu\textrm{m}$ in diameter, respectively.

• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.81-86
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• 1992

The electrophilic and nucleophilic reactions of M(S-S,ph)(N-N,H) (M = Ni(II), Pd(II), Pt(II); (S-S,ph) = 1,2-diphenylethylenedithiolate; (N-N,H)=1,10-phenanthroline) complexes have been investigated. Reaction with norbornadiene depended upon the back donating ability of the central metal ion and produced 2,5-dithia-3,4-diphenyl-tricyclo[4,4,1,0]-undeca-3,8-diene. In the reaction with methyl iodide, the effect of cleavage of (N-N,H) ligand affected the yield of methylated $M(S-S,ph)_2$ product. The structure of the thermolysis product, ${\alpha},{\alpha}{\prime}$-bismethylthiostibene $(CH_3S-SCH_3,ph)$ of methylated complexes indicates that the main product of the nucleophilic reaction is $M(CH_3S-SCH_3,ph)(S-S,ph)$. We have synthesized a new mixed-ligand complex M(S-S,CN)(N-N,H)((S-S,CN) = 1,2-dicyanoethylenedithiolate) through the nucleophilic reaction of ligand.

• Transactions on Electrical and Electronic Materials
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• v.5 no.5
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• pp.199-203
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• 2004

Superconducting B $i_2$S $r_2$C $a_{n-l}$C $u_{n}$ $O_{x}$(n=2～4) thin films were prepared by single target DC-magnetron sputtering. And, that was compared with the B $i_2$S $r_2$C $a_{n-l}$C $u_{n}$ $O_{x}$(n=1～3) thin film fabricated by using the ion beam sputtering. Phase intergrowth among n=2-3, 3-4 and 4-5 phases was observed. The molar fraction of each phase in the mixed crystal of the deposited films was determined by x-ray diffraction analyses and investigated as a function of $O_2$ gas pressure during sputtering. We investigated the changes of the superconducting properties by molar fraction of each phase. Also, the thin film surface observation was carried out by atomic force microscope. The images show the average particle size decreases, and the distribution density of particles on the film surface was to increase with lower gas pressures. The fabrication conditions for selective growth of the single n=2, 3 and 4 phases in BiSrC $a_{n-l}$C $u_{n}$ $O_{x}$(n=2～4) thin film are discussed.e discussed.ussed.

• Journal of Environmental Health Sciences
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• v.9 no.1
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• pp.31-47
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• 1983

This study was performed to investigate how much chemical constituents are contained and to what extent they are spread in the major streams running through Taegu City, i. e.: Yeechun, Beomeo, Chilsung, Dalseo, during the seven months Period between March to September, 1982. Nine constituents, pH, DO, COD, T-N, $NH_4-N, NO_2-N, NO_3-N, Cl^-, SO_4--$ and $PO_4-P---$, were found to be-contained in those streams. The results of the survey are summarized as follows. 1) Each chemical constituent detected in the five streams has the following variation range. pH(7.0-9.10), DO (ND-7.46ppm), COD (5.4-173ppm), T-N(13-42ppm), $NH^+_$-N$ (10.2-32.2ppm), $NO^-_2-N$ (0.007-2.53ppm), $NO^-_3-N$ (0.005-2.16ppm), $Cl^-$ (150-469 ppm), $SO_4^{3-}$ (71-1000ppm), $PO_4^{3-}-P$ (0.9-53ppm) The amount of all the constituents except pH, and $NO_3-N$, exceeded the standard value allowed for drinking, farming, and industrial water. 2) The monthly variation in the amount of each constituent differs according to the station from which it was sampled, but in general, the amount increased during the season from March to July when the rainfall was little while it decreased in August when the rainfall was abundant. 3) A statistical analysis of the constituents shows positive correlations that T-N and $NH^+_4-N$, water temperature and $NO^-_3-N$, but there were no ones beween the COD and $NH^+_4-N$ 4 ) The degree of COD pollution in each stream is in the following order. Kongdan, Yeechun, Beomeo, ChiLsung, and Dalseo. 5) Five major streams in Taegu City, Yeechun, Beomeo, Chilsung Dalseo, and Kongdan, are so narrow in width and so short in length that they flow into the Sincheon river or the Gumho river without undergoing self-purification. The increase in population and various kinds of industrial pollutants make the supply insufficient and water pollution inevitable. 4 ) The degree of COD pollution in each stream is in the following order. Kongdan, Yeechun, Beomeo, ChiLsung, and Dalseo.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.75-75
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• 2000

플라즈마 화학증착법(Plasma Enhanced Chemical Vapor Deposition, PECVD)을 이용하여 양질의 Si3N4 금속-유전막-금속(Metal-Insulator-Metal, MIM) 커페시터를 구현하였다. Fig.1에 나타낸 바와 같이 p형 실리콘 웨이퍼의 열 산화막 위에 1%의 실리콘을 함유하는 알루미늄을 스퍼터링으로 증착하여 전극을 형성하고 두 전극사이에 Si3N4 박막을 증착하여 MIM구조의 박막 커패시터를 제조하였다. Si3N4 유전막은 150Watt의 RF 출력하에서 반응 가스 N2/SiH4/NH3를 각각 300/10/80 sccm로 흘려주어 전체 압력을 1Torr로 유지하면서 40$0^{\circ}C$에서 플라즈마 화학증착법을 이용하여 증착하였으며, Al과 Si3N4 층의 계면에는 Ti과 TiN을 스퍼터링으로 증착하여 확산 장벽으로 이용하였다. 각 시편의 커패시턴스 및 바이어스 전압에 따른 누설 전류의 변화는 LCR 미터를 이용하여 측정하였고 각 시편의 커패시턴스 및 바이어스 전압에 따른 누설 전류의 변화는 LCR 미터를 이용하여 측정하였고 각 시편의 유전 특성의 차이점을 미세구조 측면에서 이해하기 이해 극판과 유전막의 단면 미세구조를 투과전자현미경(Transmission Electron Microscope, TEM)을 이용하여 분석하였다. 유전체인 Si3N4 와 전극인 Al의 계면반응을 억제시키기 위해 TiN을 확산 장벽으로 사용한 결과 MIM커패시터의 전극과 유전체 사이의 계면에서는 어떠한 hillock이나 석출물도 관찰되지 않았다. Fig.2와 같은 커패시턴스의 전류-전압 특성분석으로부터 양질의 MIM커패시터 특성을 f보이는 Si3N4 의 최소 두께는 500 이며, 그 두께 미만에서는 대부분의 커패시터가 전기적으로 단락되어 웨이퍼 수율이 낮아진다는 사실을 알 수 있었다. TEM을 이용한 단면 미세구조 관찰을 통해 Si3N4 층의 두께가 500 미만인 커패시터의 경우에 TiN과 Si3N4 의 계면에서 형성되는 슬릿형 공동(slit-like void)에 의해 커패시터의 유전특성이 파괴된다는 사실을 알게 되었으며, 이러한 슬릿형 공동은 제조 공정 중 재료에 따른 열팽창 계수와 탄성 계수 등의 차이에 의해 형성된 잔류응력 상태가 유전막을 기준으로 압축응력에서 인장 응력으로 바뀌는 분포에 기인하였다는 사실을 확인하였다.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.37-44
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• 1995

Concentration of particulate nitrate classified by formation mechanism and particle diameter in ambient air was determined from Feb. to Oct. 1993. Sampling was carried out using a two-stage Andersen air sampler at the top of a five-story building located at Kon-Kuk University in seoul. Concentration of N $H_{4}$N $O_{3}$ in TSP was measured by pyrolysis of sample filters at 160.deg.C for 1hr. concentration of N $H_{4}$N $O_{3}$ was higher in winter time compared with that in summmer time. Also, concentration of N $H_{4}$N $O_{3}$ was higher in fine particles compared with that in coarse particle. The range of N $H_{4}$N $O_{3}$ concentration was between 2.9 and 9.9.mu.g/ $m^{3}$. Weight fraction of N $H_{4}$N $O_{3}$ in total particulate nitrate was 31.1 .sim. 59.5%, and weight fraction of N $H_{4}$N $O_{3}$ in TSP was 2.1 .sim. 11.2%. Concentration of NaN $O_{3}$, which originated from sea salt, was highest in spring time and lowest in summer time,and the concentration range was between 0.1 and 0.7.mu.g/ $m^{3}$. NaN $O_{3}$/TSP ratio was very low (0.1 .sim. 0.4%) indicating that the portion of NaN $O_{3}$in TSP was negligible. Concentration of particulate nitrate originated from soil was 2.4 .sim. 2.9.mu.g/ $m^{3}$. Weight fraction of that in total particulate nitrate was 14.0 .sim. 37.1%.