Wastewater containing heavy metals such as copper (Cu) and nickel (Ni) is harmful to humans and the environment due to its high toxicity. Crystallization in a fluidized bed reactor (FBR) has recently received significant attention for heavy metal removal and recovery. It is necessary to find optimum reaction conditions to enhance crystallization efficacy. In this study, the effects of crystallization reagent and pH were investigated to maximize crystallization efficacy of Cu-S and Ni-S in a FBR. CaS and Na2S·9H2O were used as crystallization reagent, and pH were varied in the range of 1 to 7. Additionally, each optimum crystallization condition for Cu and Ni were sequentially employed in two FBRs for their selective removal from the mixture of Cu and Ni. As major results, the crystallization of Cu was most effective in the range of pH 1-2 for both CaS and Na2S·9H2O reagents. At pH 1, Cu was completely removed within five minutes. Ni showed a superior reactivity with S in Na2S·9H2O compared to that in CaS at pH 7. When applying each optimum crystallization condition sequentially, only Cu was firstly crystallized at pH 1 with CaS, and then, in the second FBR, the residual Ni was completely removed at pH 7 with Na2S·9H2O. Each crystal recovered from two different FBRs was mainly composed of CuxSy and NiS, respectively. Our results revealed that Cu and Ni can be selectively recovered as reusable resources from the mixture by controlling pH and choosing crystallization reagent accordingly.

점봉산 참당귀는 해발 750-965 m의 교목층은 들메나무, 고로쇠나무, 신갈나무가 분포하고, 아교목층에는 당단풍, 까치박달나무가 분포하는 계곡지로 유기물이 집적되기 쉬운 다습한 지형에 자생하였다. 참당귀 군락의 토양 분석 결과 토양pH는 4.9-6.0으로 우리나라 산림토양의 평균과 매우 유사한 값을 보였으며, 토양 양분의 지표인 유기물함량, 전질소 양이온치환용량, 치환성 Ca, K, Mg, Na의 함량은 산림토양의 평균보다 비교적 높은 값을 보였다. 생장 특성으로는 9월 말에는 뿌리 생장이 평균 47.9 g이나 10월 말에는 33.8 g으로 29% 감소하였으며, 유용 성분은 반대로 10월말에 decursin 3.8%, decursinol angelate 3.6%로 각각 26%, 67% 증가하였다. 참당귀 자생지 8개 집단의 생장 특성 및 유용성분 함량과 토양특성 간의 상관분석을 수행한 결과 뿌리 생장은 치환성 양이온인 K, Mg, Na과 높은 양의 상관관계를 보였고, 유용성분은 뿌리의 수분함량과 높은 음의 상관관계를 보였다.

Background : Wild-simulated ginseng (WSG, Panax ginseng C. A. Meyer) in Korea which depends on an artificial forest growth method. Methods and Results : WSG samples were collected from 8 different regions in Korea in October, 2017, and these were analyzed by ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF MS) using optimized analytical methods to compare the metabolite patterns to cultivated regions. Furthermore, their metabolite compositions differed according to individual plant samples. The metabolite profiling data were processed by multi-variate statistical analyses such as PCA and PLS-DA to determine the differences among geographical origins. To identify significant metabolites according to regional variances of WSG, more sophisticated multi-variate statistical analyses such as metabolite selection should be performed. Conclusion : This metabolomics approach can also be applied to evaluate the overall quality of WSG, as well as to discriminate the cultivars for the medicinal plant industry.

In an attempt to connect English material development and grammar teaching for the purpose of attaining communicative competence, this study looks at existential there constructions from the perspective of theoretical background and practical applications. To fulfill the pedagogical needs of the ‘There-constructions’, theoretical framework established to the present is examined and the frequency of authentic use is investigated on the ground of several corpora including non-native learner corpus. In addition, a writing task was given to Korean learners of English who were asked to describe pictures eliciting existential there related sentences and, as a result, the learners’ errors have been identified. Middle school English textbooks are, also, analyzed in light of a material evaluation checklist as a textbook, one of the main resources in EFL context, could reveal to what extent the learners are exposed to the corresponding grammar items. The study, eventually, draws some pedagogical implications and suggestions by presenting a communicative grammar teaching model as well as a material development guide to ‘There-constructions’ teaching.