본 연구는 한국 비례대표제의 변화 과정을 통해 준연동형 비례대표제를 검토하면서 제22대 비례대표 국회의원선거에서 나타나는 정당의 공천 과정 과 선거 결과를 분석하였다. 한국의 비례대표제는 지역구에 기반한 제1당 우 선적 배분 방식에서 시작해 지역구에 기반한 병립형 비례대표제, 1인 2표 정당명부식 병립형 비례대표제, 1인 2표 정당명부식 준연동형 비례대표제로 변화하였다. 제22대 비례대표 국회의원선거를 위한 후보의 공천 과정은 절 차적으로는 정당성과 투명성에 기반한 것으로 보이지만 현실적으로는 각 정 당이 영입한 인사를 공천하는 한계를 보였다. 제22대 비례대표 국회의원선 거 결과는 유력한 여야의 위성정당이 전체의석의 69.57%를 차지하였고, 지 역구 후보를 공천하지 않은 더불어민주연합과 국민의미래, 조국혁신당이 전 체의석의 95.65%를 차지하였다. 준연동형 비례대표제는 정당의 이해관계에 따라 제도적으로 오용됨으로 비례대표 정당의 지역구 공천 하한선을 도입하 고, 대표성을 위해 연령별로 최소할당제를 도입할 필요가 있다.

Combination of liquid-phase exfoliation and hydrothermal method has progressed in recent years mainly on production of 2D materials. In this study, graphene was successfully synthesized via combinatorial of liquid-phase exfoliation and hydrothermal method with the aid of various conductive surfactants perylene-3, 4, 9, 10-tetracarboxylate (PTCA), lithium perylene-3, 4, 9, 10-tetracarboxylate (LiPTCA) and sodium perylene-3, 4, 9, 10-tetracarboxylate (NaPTCA). The effect of the lithium ( Li+) and sodium ( Na+) cations toward the efficiency of the graphene exfoliation process and its electrical properties was thoroughly investigated. Based on the characterization techniques, it is revealed that NaPTCA is the ideal conductive surfactant to exfoliate graphene sheets. X-ray diffraction spectra verified that the Na+ cation certainly can enhance the exfoliation process by expanding the interlayer spacing. The lateral size of the graphene sheets with Na-PTCA surfactant was the smallest (4.17 μm) as observed from SEM micrograph. The maximum concentration of the graphene yield was achieved up to 0.151 mgmL− 1 in NaPTCA surfactant alongside with excellent electrical conductivity of 746.27 Sm− 1 and relevant specific capacitance of 129 Fg− 1.

This study was conducted to investigate the changes of hormone levels of serum progesterone (P4) and estradiol-17 β (E2) in sows of Landrace (L), Yorkshire (Y) and F1 (L × Y) (respectively n=3) with excellent ability, and to provide a baseline data for improving reproductive performance. In this experiment, the sows at the age of 12 months or more were used. The sows were fed by two way methods, one is conventional methods and the other is 3 days-flushing feed before estrus. Each pig’s blood was collected in 3, 6, 9, 12, 15 and 18 days after the estrus for the analyses of P4 and E2. Serum was separated by centrifugation for 15 min. with 3,000 rpm. Progesterone and estradiol-17β were measured by immunochemical assay (ELIZA test). In conventional feeding, serum progesterone levels were significantly (p<0.01) higher in F1 than in L and Y. No significant differences in P4 concentrations were seen between the L and Y of sows. Serum E2 levels were similar the serum progesterone levels. In the case of flushing feed, the tendency of hormonal changes were similar to conventional methods. But almost of hormonal levels were a little higher than that of conventional methods. P4 level of L and Y in flushing feed were significantly different (p<0.01). Serum E2 level of Y in flushing feed was significantly different among the breeds (p<0.01). These results were similar to the tendency of hormonal changes in general sows and moreover, flushing feed is known to develop the swine production, these results proved the fact of the methods. And these results suggested that more studies about hormonal changes in sows according to seasonal and nutritional factors should be needed.

A xylan-decomposing Gram-positive bacterium, Cellulosimicrobium cellulans DY-8, was isolated from the gut of a wood-feeding longicorn beetle, Moechotypa diphysis. To amplify a partial fragment of the GH 10 β-1,4- xylanase (XylC) gene of strain DY-8, two degenerated oligonucleotide primers were designed based on strictly conserved regions (WDVVNE and ITELLDV) in the GH family 10 xylanolytic enzymes. The full gene (1488-bp) of XylC, which was predicted to encode a protein consisting of 495 amino acids with a molecular mass of 52.0 kDa and a calculated pI of 6.49, was cloned by repeated DNA walking and nested PCR protocols. The results of a protein blast survey showed that XylC was a β -1,4-xylanase comprised of an N-terminal catalytic GH10 domain (from Ser48 to Leu338) and a C-terminal RICIN domain (from Tyr359 to Leu492). This overall structure of XylC was 57% identical to that of Actinoplanes sp. SE50/110 β -1,4-xylanase (Accession number: YP_006265966), which has not yet been biochemically characterized.

전해정련을 이용한 폐 피복관 처리의 타당성을 살펴보기 위하여, 500℃의 LiCl-KCl 용융염 내에서 표면이 산화된 10 g 규모의Zircaloy-4 피복관 및 순수한 Zircaloy-4 피복관의 전기화학적 거동을 살펴보았다. 산화된 Zircaloy-4 피복관이 담긴 basket을 작업전극으로하여 전압-전류 관계를 측정한 결과, 산화되지 않은 Zircaloy-4 피복관과 비교해 Zr의 산화 peak는 Ag/AgCl 기준전극 대비, 약 -0.7 V ~ -0.8 V로 유사한 반면, 산화 전류의 크기는 확연하게 감소하는 것으로 나타난다. 이러한 결과는 -0.78V의 일정전위를 가한 전기화학적 용해 실험에서 살펴본 전류-시간 곡선에서도 유사하게 나타나며, 피복관 조각들의 평균 두께 및 무게 변화로부터 확인할 수 있다. Zircaloy-4 피복관이 산화되었을 경우, 표면의 산화막이 피복관의 전도성에 영향을 주어 basket 내 위치에 따라 전기화학적 용해의 균일성 및 속도를 떨어뜨리는 것으로 나타나지만, 표면의 미세한 결함과 Zr 산화물의 상 특성으로 인해 전기화학적 용해가 진행되는 것으로 판단된다.

본 연구에서는 Al-10wt%Ti-4wt%Fe 복합재료를 in-situ공정으로 제조할 수 있는 가능성 및 2 원계 Al-10wt%Ti 복합재료의 낮은 기계적 성질(탄성계수, 상온 고온강도, 내마모특성 등)을 PM SiC/2124 복합재료 수준 흑은 그 이상으로 향상시킬 수 있는 가능성을 조사하였다. 제조된 Al-10wt%Ti-4wt%Fe 합금은 불연속 SiC 강화상으로 보강된 Al-기지 복합재료(SiCw/2124)와 유사한 미세구조를 보여주었으며, 탄성계수 및 인장강도, 내마모성질 등의 기계적 특성이 2원계 Al-10%Ti 합금각 비교해 현저하게 향상되었음이 관찰되었다. 위의 결과는 초정 Al3Ti상 외에도 Fe 원소의 첨가를 통한 추가적인 AlxFe의 분산강화 효과에 기인한 것으로 해석된다.

과냉각액체구역(δTx=Tx-Tg)을 갖는 Fe80P10C6B4 조성에 천이금속(Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Ni, Pd, Pt및 Cu)를 첨가하여 이들 원소가 유리화온도(Tg), 결정화온도(Tx) 및 과냉액체구역 (δTx)에 미치는 영향에 ?여 조사하였다. Fe80P10C6B4 합금의 δTx 값은 27K였으나 이 합금에 Hf, Ta 및 Mo을 각각 4at%첨가하면 그 값이 40k 이상으로 증가하였다. 이같은 δTx 값의 증가는 유리화온도(Tg의 상승보다 결정화온도(Tx)의 상승폭이 크기 때문이다. Tg 및 Tx는 외각전자밀도(e/a)가 약 7.38에서 7.05로 감소할수록 상승하였다. e/a의 감소는 천이금속과 다른 구성원소(반금속)사이의 상호결합상태를 의미한다. 즉 Tg 및 Tx의 상승은 강한 상호결합력에 기인하는 것으로 사료된다.

This study investigates the characteristics of diurnal, seasonal, and weekly roadside and residential concentrations of PM10 and PM2.5 in Busan, as well as relationship with meteorological phenomenon. Annual mean PM10 and PM2.5 concentrations in Busan were 44.2 ㎍/m3 and 25.3 ㎍/m3, respectively. The PM2.5/PM10 concentration ratio was 0.58. Diurnal variations of PM10 and PM2.5 concentrations in Busan were categorized into three types, depending on the number of peaks and times at which the peaks occurred. Roadside PM10 concentration was highest on Saturday and lowest on Friday. Residential PM10 concentration was highest on Monday and lowest on Friday. Residential PM2.5 concentration was highest on Monday and Tuesday and lowest on Friday. PM10 and PM2.5 concentrations were highest on Asian dust and haze, respectively. The results indicate that understanding the spaciotemporal variation of fine particles could provide insights into establishing a strategy to control urban air quality.

Considering the high potential of the widely-used halogenated hydrocarbons on the global warming and ozone depletion, the development of effective thermal destruction methods of these compounds are quite urgent and indispensible. As part of the research efforts of this area, the destruction of CCl4 and flame characteristics have been investigated numerically by the co-firing CCl4 with CH4 in an industrial LNG-fired combustor as a function of molar ratio of the CCl4 to CH4 using a commercial code of STAR-CCM+. Considering a broad range of Damkohler number associated with the process of intensive CHCs (Chlorinated hydrocarbons) combustion with auxiliary fuel together with the inhibition reaction especially near flammability limits, a proper combustion modeling of CCl4 thermal destruction is quite desirable. In this study, however, after careful review of the literature about the flame characteristics of halogenated hydrocarbon together with the previous study about the modeling of the CCl4 flame based on the data of burning velocity, the eddy breakup turbulent combustion model was employed since it is quite reasonably assumed that chain branching reaction looks dominant in most flame region over the halogenated inhibition effect in strong turbulent reacting flows. One of the most useful results based on this study is that; without any incorporation of flame inhibition effect, the length of co-fired flame increases steadily as the ratio of CCl4 to CH4 (R) increases from 0.0, 0.1, 0.2 to 0.5, and 1.0 together with the increase of the maximum flame and exit gas temperature. The reason of the increase of the flame length with the increase of flame temperature can be explained by the presence of the additional CCl4 fuel with low heating value. Further a detailed discussion has been made on the thermal destruction of CCl4 together with the Cl2 concentration by Deacon reaction.

본 연구에서는 자연에서 산출빈도가 높은 3가 비소(아비산염)와 two-line ferrihydrite와의 표면흡착반응의 기작을 살펴보기 위하여 3가 비소를 흡착시킨 two-line ferrihydrite에 대한 X선 흡수분광 분석을 수행하였다 연구에 사용된 two-line ferrihydrite는 실험실에서 합성하여 사용하였으며, 산성과 염기성 환경에서의 표면반응 기작을 비교하기 위하여 pH 4와 10에서 연구를 수행하였다. 또한 각 pH 조건별 3가 비소의 흡착농도에 따른 표면반응의 차이를 비교 평가하였다. X선 흡수분광 분석결과에서 얻은 EXAFS 영역에서의 비소 3가에 대한 구조 변수들을 살펴보면 As-O 배위수는 3.1~3.3개 거리는 1.74~1.79 a으로 two-line ferrihydrite 표면에 흡착된 As(III) complex의 구조 단위체가 AsO3임이 확인되었다. As(III)-Fe쌍은 주로 안정된 형태의 bidentate binuclear comer-sharing (2C)의 결합구조를 갖는 것으로 나타났으며, bidentate mononuclear edge-sharing (2E)와 2C가 혼합된 결합구조도 공존하는 것으로 조사되었다. pH 4에서는 흡착농도에 따라 다른 표면구조를 가지는 반면, pH 10에서는 흡착 농도에 상관없이 동일한 표면구조를 보이는 것으로 나타났다. 이러한 결과는 3가 비소와 two-line ferrihydrite의 표면반응은 pH와 농도에 의해서 영향을 받는다는 거시적인(macroscopic) 흡착실험 연구결과가 미시적인(microscopic) X선 흡수분광 결과에 의해서 해석될 수 있음을 의미한다.