• 환경위생공학
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• 제19권1호
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• pp.8-16
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• 2004

Ground water samples were collected from residential, green" industrial, landfill and mining area and analyzed for 23 inorganics from March to October in 2002. The results are as follows; 1. The detection frequencies of inorganic materials such as As, Ba, B, Mo, Ca, Mg, Al, Cu, Fe, Mn, Zn, Na, K were 7.2∼77.1% which showed that these inorganics were detected in many ground waters. 2. The detection frequencies of 7 inorganics(Cd, Cr, Ph, Se, Sb, Be, Tl) were commonly low at ranging from 0.42 to 2.5%. These inorganics were contained in ground water partially. 3. Three inorganics such as Hg, Ni, Ag were not detected in any ground-water samples. 4. Compared to the other areas, ground water samples from landfill area contained greater concentration in many inorgainics and then showed higher levels in industral, residential, mining and green area in order. 5. Compared to noted concentrations of bottled water, inorganic minerals including Ca, Mg, Na, K related to taste were fluent in target samples. The results showed that the average concentrations of Mg, Na, K were 4.0 mg/l, 14.7 mg/l, 1.5 mg/l respectively. 6. The concentrations of inorganics such as Sb, Ba, Mo, Be, Tl, K in some ground water samples exceeded the water quality standards of WHO, the US and UK. Especially, Ba, Mo, K also showed relatively high detection frequencies so these inorganics need to be considered as analytes in Korea Drinking Water Regulation in further study.

• Carbon letters
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• 제17권1호
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• pp.74-78
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• 2016

• Bulletin of the Korean Chemical Society
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• 제26권10호
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• pp.1603-1606
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• 2005

• 공업화학
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• 제26권5호
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• pp.526-532
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• 2015

신 기후변화대응(Post 2020)을 위한 대체에너지의 역할과 더불어 태양전지의 중요성이 높아져 가고 있다. 태양전지의 종류는 크게 재료관점에서 보면 유기물과 무기물 계열로 구분할 수 있지만 대규모 발전역할에서는 현재까지 실리콘과 같이 양산성과 안정성 기반의 무기물 태양전지가 주된 역할을 하고 있다. 특히 최근 몇 년간 화합물반도체 태양전지에 대한 연구는 급속도로 가속화되면서 3-5족 적층형 태양전지, chalcopyrite 계열 $CuInGa(S,Se)_2$ (CIGSSe) 태양전지와 kesterite 계열 $Cu_2ZnSn(S,Se)_4$ (CZTSSe) 태양전지 연구가 대표적으로 주류를 이루어 왔다. 따라서 화합물반도체 태양전지에서 주류를 이루고 있는 3-5족 적층형, CIGSSe 및 CZTSSe 태양전지들의 연구개발동향 및 기술적인 주요내용들에 대해 소개하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.843-846
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• 1992

This thesis was investigated on optical-and ion-induced characteristics in positive(a-$Se_{75}Ge_{25}$) and negative (Ag/a-$Se_{75}Ge_{25}$) resists for focused-ion-beam microlithogaphy. The a-$Se_{75}Ge_{25}$ inorganic thin film shows an increase in optical absorption after exposure to$\sim$$10^{16}$ dose(ions/$cm^{2}$) of Ga ions. The observed shift in the absorption edge toward longer wavelengths is consistent with that in films exposed to band-gap photons ($\sim$$10^{20}$ photons/$cm^{2}$). But, ion induced shift is twice as much as that in film exposed to optical radiation. This result may be related with microstructural rearrangements with in the short range of SeGe network. Due to changes in the short range order, the chemical bonding may be affected, which results in increased chemical dissolution in ion-induced film. Also, this resist exhibits good thermal stability because of its high Tg(~220$^{\circ}C$). The composition of deposited film measured by AES is consistent with that of bulk.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• 한국토양비료학회지
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• 제44권2호
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• pp.308-315
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• 2011

Ammonium- and potassium-loaded zeolite (NK-Z) and other four kinds of environmental friendly fertilizers/agents were applied to characterize their effectiveness on garlic (Allium sativum L.) growth and soil amelioration. Selenium dioxide ($SeO_2$) and germanium dioxide ($GeO_2$) liquid treatments significantly increased selenium (Se) and germanium (Ge) contents in garlic stems, garlic cloves and clove peels. In soil treated with ZBFC, Se contents in garlic stems, cloves, and clove peels was 13.89-, 12.79-, and 10.96-fold higher, respectively, than in the controls. The inorganic contents of plants grown in soil treated with functional strengthened fertilizers were also higher than in plants grown in control soil. Soil treated with arbuscular mycorrhizal fungi (AMF) agents exhibited significantly greater spore density and root colonization rate than in untreated soil. The density of chitinolytic microorganisms in soil treated with colloidal chitin was also significantly higher than in untreated soil. The cation exchange capacities (CEC) in ZAFC-, ZBFC-, and ZBF-treated soils was 16.05%, 8.95%, and 8.80% higher than in control soil 28 weeks after sowing.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3362-3366
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• 2013

A simple and quick separation technique for selenite in natural water was developed using $TiO_2$@$SiO_2/Fe_3O_4$ nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the $TiO_2$ shell. The synthesized nanoparticles were used to separate selenite ($Se^{4+}$) in the presence of $Se^{6+}$ or selenium anions for the photocatalytic reduction to $Se^0$ atom on the $TiO_2$ shell, followed by magnetic separation using $Fe_3O_4$ nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis.

• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.193-199
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• 2000

As an energetic focused-ion beam(FIB) is irradiated on an inorganic amorphous thin film a majority of ions without a reflection at surface, is randomly collided with constituent atoms in thin film. but their distribution exhibits generally a systematic form of distribution. In our previous paper we reported the concentration distribution and the transmission per unit depth of Ga$^{+}$ ions penetrated int a-Se$_{75}$ /Ge$_{25}$ thin film using the LSS-based calculation. In this paper these simulated results are compared with those obtained by a conventional profile code(ISC) and a practical SIMS profile. Then the results of LSS-based calculation have only a small difference with those of code and SIMS Especially. in the case of Ga$^{+}$-FIB with an accelerating energy of 15keV. the depth of the maximum ion concentration is coincident with each other in an error range of $\pm$5$\AA$.EX>.

• 세라미스트
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• 제22권2호
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• pp.146-169
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• 2019

To overcome the theoretical efficiency of single-junction solar cells (> 30 %), tandem solar cells (or multi-junction solar cells) is considered as a strong nominee because of their excellent light utilization. Organic-inorganic halide perovskite has been regarded as a promising candidate material for next-generation tandem solar cell due to not only their excellent optoelectronic properties but also their bandgap-tune-ability and low-temperature process-possibility. As a result, they have been adopted either as a wide-bandgap top cell combined with narrow-bandgap silicon or CuIn_xGa_(1-x)Se₂ bottom cells or for all-perovskite tandem solar cells using narrow- and wide-bandgap perovskites. To successfully transition perovskite materials from for single junction to tandem, substantial efforts need to focus on fabricating the high quality wide- and narrow-bandgap perovskite materials and semi-transparent electrode/recombination layer. In this paper, we present an overview of the current research and our outlook regarding perovskite-based tandem solar technology. Several key challenges discussed are: 1) a wide-bandgap perovskite for top-cell in multi-junction tandem solar cells; 2) a narrow-bandgap perovskite for bottom-cell in all-perovskite tandem solar cells, and 3) suitable semi-transparent conducting layer for efficient electrode or recombination layer in tandem solar cells.