• 한국환경농학회지
• /
• 제18권1호
• /
• pp.28-34
• /
• 1999

전국의 16개 휴 ${\cdot}$ 폐광 지역에서 토양중 중금속함량과 식생조사를 실시한 결과를 요약하면 다음과 같다. 조사 휴 ${\cdot}$ 폐광산 대부분의 경우 피복식물이 없는 나대지로 존재하고 있었고 유기물함량, CEC 등이 낮은 값을 가지고 있는 등 대체로 척박한 토양조건을 가지고 있었으며 특정 중금속으로 인한 오염의 정도가 토양환경보전법상의 우려기준과 대책기준을 초과하는 지점도 있었다. 식물종들의 분포를 조사한 결과 목본은 소나무, 아카시나무 등이, 초본은 쑥과 억새의 출현빈도가 높았다. 쑥은 지상부에 Zn과 Cd를 각각 1,191, 26.35mg/kg을 함유하였고, 패랭이꽃은 Cu를 405mg/kg 함유하여 체내 농도가 가장 높은 것으로 조사되었다. 체내 중금속함량, 건물생산량, 생육기간등을 고려할 때 쑥, 억새, 달맞이꽃등이 토양정화식물로서의 가치가 있다고 생각된다. 앞으로 쑥을 비롯한 내성이 있는 식물종에 대한 조사는 물론 생리적 특성, 토양조건, 기후조건 등에 대한 지속적 연구가 뒤따라야 할 것으로 생각된다.

• 통합자연과학논문집
• /
• 제2권1호
• /
• pp.18-23
• /
• 2009

This minireview provides the chosen examples of our recent discoveries in the polymerization of hydrosilanes, dihydrosilole, lactones, and vinyl derivatives using various catalysts. Hydrosilanes and lactones copolymerize to give poly(lactone-co-silane)s with $Cp_2MCl_2$/Red-Al (M = Ti, Zr, Hf) catalyst. Hydrosilanes (including dihydrosilole) reduce noble metal complexes (e.g., $AgNO_3$, $Ag_2SO_4$, $HAuCl_4$, $H_2PtCl_6$) to give nanoparticles along with silicon polymers such as polysilanes, polysilole, polysiloxanes (and silicas) depending on the reaction conditions. Interestingly, phenylsilane dehydrocoupled to polyphenylsilane in the inert nitrogen atmosphere while phenylsilane dehydrocoupled to silica in the ambient air atmosphere. $Cp_2M/CX_4$ (M = Fe, Co, Ni; X = Cl, Br, I) combination initiate the polymerization of vinyl monomers. In the photopolymerization of vinyl monomers using $Cp_2M/CCl_4$ (M = Fe, Co, Ni), the photopolymerization of MMA initiated by $Cp_2M/CCl_4$ (M = Fe, Co, Ni) shows while the polymerization yield decreases in the order $Cp_2Fe$ > $Cp_2Ni$ > $Cp_2Co$, the molecular weight decreases in the order $Cp_2Co$ > $Cp_2Ni$ > $Cp_2Fe$. For the photohomopolymerization and photocopolymerization of MA and AA, the similar trends were observed. The photopolymerizations are not living. Many exciting possibilities remain to be examined and some of them are demonstrated in the body of the minireview.

• 대한화학회지
• /
• 제56권2호
• /
• pp.246-250
• /
• 2012

An efficient access, single step and environmentally benign synthesis of a new series of pyrazole containing isoxazolines derivatives were prepared by the condensation of chalcones bearing pyrazole moiety with hydroxyl amine hydrochloride in basic condition by using polyethylene glycol-400 (PEG) as a greener reaction solvent. The advantages of the present methodology are mild reaction condition and avoidance of volatile organic solvent. Furthermore, these newly synthesized compounds were screened for their antimicrobial activity against various pathogens like Escherichia coli (MTCC 2939), Salmonella typhi (MTCC 98), Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 441), Aspergillus niger (MTCC 281), Aspergillus flavus (MTCC 2501), Penicillium chrsogenum (MTCC 160) and Fusarium moniliformae (MTCC 156). Especially compound containing the hydroxyl group in C2-position and presence of halo (I, Br and Cl) groups as substituents at $C_3$ and $C_5$ position on the benzene nucleus showed the higher activity. Furthermore, compounds bearing methyl groups in combination with I and Br which enhanced the activity.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
• /
• pp.188-192
• /
• 2004

Composting experiment was conducted with the mixing ratio of food waste versus sewage sludge being respectively 10:90, 30:70, 50:50, 60:40, 70:30 and 90:10 wt%. The fermentation temperature was $18-22^{\circ}C$ in the beginning, and then it was sharply increased to $44-66^{\circ}C$ up to 1 day after fermentation, which was maintained for more than 3 days. Then, it was slowly decreased to $18-25^{\circ}C$ up to 8 days after fermentation, which was maintained all the time. In conclusion, it could be known from examination of various conditions, including reaction rate, salinity, C/N ratio, temperature, organic substance, etc. while composting of food waste that in case food waste and sewage sludge were mixed at the mixing rate of 60:40 wt%, the most ideal composting reaction occurred.

• 자원환경지질
• /
• 제28권2호
• /
• pp.147-154
• /
• 1995

Coal fly ashes collected from the Samcheonpo and the Seocheon Power Plants were analyzed for major and minor components and heavy metals such as As, Cd, Co, Cr, Cu, Ga, Hg, Mo, Ni, Pb, Sb, V and Zn in order to suggest basic data to apply coal fly ash as fertilizer or soil ameliorator. The specific gravity of the samples was less than 2.0, and amounts of organic matter range from 5.0% to 12.3%. The identified minerals by XRD were mainly quartz, mullite and pyrite in anthracite coal, and mainly quartz and mullite in bituminous coal. Generally, the contents of heavy metal elements analyzed were lower less than those of soil, though higher in some samples. Element couples of some elements( e.g., As-Mo, Zn ; Mo-As, Sb, V, Zn ; Sb-Zn ) show positive correlations with each other, but the high correlations of toxic elements such as As, Pb, Cd and Hg indicate to give attention to apply coal fly ash as fertilizer or soil ameliorator.

• 방사성폐기물학회지
• /
• 제6권1호
• /
• pp.55-63
• /
• 2008

고준위폐기물처분장의 완충재 물질로 사용되는 팽윤성 점토는 방벽재로서 그 기능을 제대로 발휘하기 위해 오랫동안 물리 화학적으로 안정해야 한다. 팽윤성 점토의 장기건전성 관련인 자들을 검토하고, 처분장 성능에 대한 각 인자의 중요성을 평가하였다. 검토결과, 붕괴 열에 의한 온도상승, 지하수 화학, 콘크리트에 의한 pH 증가, 유기물과 미생물, 방사선 조사 및 기계적 교란은 완충재물질로서 팽윤성 점토의 장기건전성에 중요한 인자임을 확인하였다. 본 연구는 고준위폐기물 처분장에서 팽윤성 점토의 완충재 설계를 위한 기초자료로 유용하게 활용될 것이다.

• 통합자연과학논문집
• /
• 제10권4호
• /
• pp.175-191
• /
• 2017

In organic chemistry amide synthesis is performed through condensation of a carboxylic acid and an amine with releasing one equivalent of water via the corresponding ammonium carboxylate salt. This method is suffering from tedious processes and poor atom-economy due to the adverse thermodynamics of the equilibrium and the high activation barrier for direct coupling of a carboxylic acid and an amine. Most of the chemical approaches to amides formations have been therefore being developed, they are mainly focused on secondary amides. Direct carbonylations of tertiary amines to amides have been an exotic field unresolved, in particular direct carbonylation of trimethylamine in lack of commercial need has been attracted much interests due to the versatile product of N,N-dimethylacetamide in chemical industries and the activation of robust N-C($sp^3$) bond in tertiary amine academically. This review is focused mainly on carbonylation of trimethylamine as one of the typical tertiary amines by transition metals of cobalt, rhodium, platinum, and palladium including the role of methyl iodide as a promoter, the intermediate formation of acyl iodide, the coordination ability of trimethylamine to transition metal catalysts, and any possibility of CO insertion into the bond of Me-N in trimethylamine. In addition reactions of acyl halides as an activated form of acetic acid with amines are reviewed in brief since acyl iodide is suggested as a critical intermediate in those carbonylations of trimethylamine.

• 환경위생공학
• /
• 제21권4호
• /
• pp.77-86
• /
• 2006

The water purification was very important in Korea which has not sufficient water resource and while adsorption method among the various methods to eliminate the water pollutants has been widely used by activated carbon. This study was conducted the basic experiment for hall distribution, pH, conductivity, electronic microscope, cation exchange and inorganic materials the adsorption capacity of Korean traditional charcoal which has similar characteristics to activated carbon of organic pollutants. As a result of observing Korean traditional charcoal with electronic microscope, it was found that it has porous structure, oak charcoal has circular structure, pine charcoal has square structure and bamboo charcoal has hexagonal structure, which has high void fraction per unit area because of its thin cell wall structure. As a result of experimenting hall distribution, hall distribution of bamboo high temperature charcoal is high as 0.269cc/g and has the greatest inorganic contents and cation exchange capacity(CEC) which are the important factor of chemical adsorption.

• Bulletin of the Korean Chemical Society
• /
• 제24권3호
• /
• pp.285-290
• /
• 2003

An analytical method for the simultaneous determination of trace Ge, As and Se in biological samples by inductively coupled plasma/mass spectrometry has been investigated. The effects of added organic gas into the coolant argon gas on the analyte signal were studied to improve the detection limit, accuracy and precision. The addition of a small amount of methane (10 mL/min.) into the coolant gas channel improved the ionization of Ge, As and Se. The analytical sensitivity of the proposed Ar/CH₄system was superior by at least two-fold to that of the conventional Ar method. In the present method, the detection limits obtained for Ge, As and Se were 0.014, 0.012 and 0.064 ㎍/L, respectively. The analytical reliability of the proposed method was evaluated by analyzing the certified standard reference materials (SRM). Recoveries of 99.9% for Ge, 103% for As, 96.5% for Se were obtained for NIST SRM of freeze dried urine sample. The proposed method was also applied to the biological samples.

• Mycobiology
• /
• 제37권2호
• /
• pp.94-102
• /
• 2009

Ganoderma applanatum is one of the most popular medicinal mushrooms due to the various biologically active components it produces. This study was conducted to obtain basic information regarding the mycelial culture conditions of Ganoderma applanatum. Based on the colony diameter and mycelial density, PDA, YMA and MCM media were suitable for the mycelial growth of the mushroom. The optimum temperature for mycelial growth was found to be $25{\sim}30^{\circ}C$. The optimum carbon and nitrogen sources were mannose and dextrin, respectively, and the optimum C/N ratio was 2 to 10 when 2% glucose was used. Other minor components required for the optimal growth included thiamine-HCl and biotin as vitamins, succinic acid and lactic acid as organic acids, and $MgSO_4$ $7H_2C$, $KH_2PO_4$ and NaCl as mineral salts.