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      • 포항산 천연 제올라이트와 합성 제올라이트에 의한 금속 이온의 제거

        박상윤,장세복,김덕수,김양 濟州大學校 基礎科學硏究所 1996 基礎科學硏究 Vol.9 No.2

        국내 경상북도 포항시 남구에서 채취한 4종의 천연 제올라이트를 화학성분 분석, X-선 회절, 열시차분석 실험, 열중량분석 실험으로 분석하였다. 이들 제올라이트의 주성분은 석영, mordenite, heulandite가 함유된 clinoptilolite이었다. NaOH, Ca(OH)₂, HCI 용액으로 처리한 천연 제올라이트의 성질은 X-선 회절법과 열시차분석 실험법으로 연구하였다. 천연 제올라이트와 화학적으로 처리한 제올라이트, 합성 제올라이트를 이용하여 Cu²+, Cd²+, Hg²+, Pb²+, Cr6+등의 중금속 이온과 알칼리 금속 K- 이온의 제거능력을 비교하였고, 중금속 이온 용액의 pH값과 초기농도, 중금속 이온을 제거하는데 소요되는 반응 시간의 효과 등을 비교하였다. 천연 제올라이트에 Ca²+, Pb²+, and Cu²+ 이온용액을 각각 5ppm첨가한 결과 제거율이 94%, 95%, 97%까지 증가되었다. 또한 0.5N NaOH와 0.5 N HCI 용액으로 처리한 매석산 천연 제올라이트를 이용하여 Hg²+ 이온용액을 5ppm 첨가한 결과 제거율이 약 80% 정도였다. 매석산 천연 제올라이트와 합성 제올라이트 A,X 및 Y가 Hg²+ 이온의 최대 제거율을 나타내었다. The four natural zeolites collected in Pohang, Kyungsang buk-do, Korea, were analyzed by means of wet chemical methods, X-ray diffraction, DTA, and TGA. The results indicate that the primary species of those zeolites are clinoptilolite mixed with quartz, mordenite, and heulandite. These zeolites were treated with NaOH, Ca(OH)₂, and HCI solution and their differences were also studied by X-ray diffraction method and differential thermal analysis method. The capabilities of removing heavy metal ions, such as Cu²+, Cd²+, Hg²+, Pb²+ and Cr6+, and alkaline ion, K+ ions with original zeolites, chemically treated zeolites, and synthetic zeolites were compared. The effect of pH value of solution and initial concentration of heavy metal ions, and the effect of reaction time in removing heavy metal ions were ions were studied. The experimental results showed that up to 94%, 95%, and 97% of Ca²+, Pb²+, and Cu²+ ions could be removed, respectively, out of 5 ppm of untreated natural zeolites. About 80% of the Hg²+ ions could be also removed out of 5 ppm Hg²+ ions solution with Maesuk mt. natural zeolite which was treated with 0.5N NaOH and 0.5 N HCI solution. It was found that Maesuk mt. natrual zeolite was most efficient in removing Hg²+ ions compared with the other natural zeolites studied in this work and synthetic zeolite A, X and Y.

      • Crystal Structure of a Methanol Sorption Complex of Dehydrated Partially Cobalt(Ⅱ)-Exchanged Zeoite A

        韓榮旭,張世福,金洋 부산교육대학교 과학교육연구소 1993 科學敎育硏究 Vol.18 No.-

        부분적으로 Co^2+ 이온으로 치환한 제올라이트 A를 탈수한 후 메탄올을 흡착한 결정구조(a=12.169(1) A)를 입방공간군 Pm3m를 사용하여 단결정 X-선 회절법으로 해석하고 정립화하였다. 이 결정은 360˚C에서 2±10^+Torr 하에서 2일간 진공 탈수한 후 22(1)˚C에서 약 104Torr의 메탄올 증기로 약 1시간동안 흡착시켰다. Full-matrix 최소자승법 정밀화 계산에서 1>3α(1)인 147개의 독립 반사를 사용하여 최종 오차 인자를 R1=0.061, R2=0.062까지 정밀화시켰다. 단위세포당 4개의 Co^2+ 이온과 1.5개의 Na^+ 이온은 6-링 산소와 결합하고 있었다. 4개의 Co^2+ 이온은 0(3)의 (111) 평면에서 큰 동공 쪽으로 약 0.44 (18)A 들어가 위치하고 1.5개의 Na^+ 이온은 0(3) (111)평면에서 소다라이트 동공 깊숙히 약 0.55A 들어간 자리에 이치하고 있다. 단위세포당 약 6.5개의 메탄올 분자가 흡착되었다. 단위세포당 약 6.5개의 메탄올 분자는 큰 동공 내에 위치하였고 4개의 Co^2+ 이온과 2.5개의 Na^+ 이온과 결합하고 있다.. 4개의 산소는 6-링에 위치한 Co^2+ 이온과 결합하고 나머지 2개의 산소는 6-링에 위치한 Na^+ 이온과 결합하고 있다. The crystal structure of a methanol sorption complex of dehydrated partially Co(Ⅱ)-exchanged zeolite A, Co_4Na_4-A 6.5CH_3OH(a=12.169(1) A˚), has been determined by singlecrustal x-ray diffraction techniques in the cubic space group Pm3m at 21(1)℃. Co_4Na_4-A was dehydrated at 360℃ and 2×10^-6 Torr for 2 days, followed by exposure to about 105 Torr of methanol vapor at 22(1)℃ for 1 hr. The structure was refined to fina error indices, R_1=0.061 and R_3=0.060 with 147 reflections, for which Ⅰ > 3σ(Ⅰ). In this structure, four Co^2+ ions and 1.5 Na^+ ions per unit cell lie at 6-ring positions:the Na^+ ions are recessed 0.444(18)A˚ into the sodalite unit and the Co(Ⅱ) ions extend ca. 0.55A˚ into the large cavity. 2.5 Na^+ ions lie in an 8-oxygen ring plane. The 6.5 methanol molecules are sorbed per unit cell. The 6.5 methanol oxygens, all in the large cavity, associate with the 4 Co^2+ ions and 2.5 Na^+ ions in two ways:four oxygens coodinate to 6-ring Co^2+ ions, and two coordinate to 8-ring.

      • 조리방법에 따른 식품 중 영양소 잔존률(retention factor)에 관한 연구(Ⅰ) : 채소류 및 감자류 Vegetablesn ane potatoes

        김대병,장영미,김인복,이혜영,장재희,박정현,엄세정 식품의약품안전청 2000 식품의약품안전청 연보 Vol.4 No.-

        조리조건에 따른 식품의 영양소 잔존를을 측정하여 보다 정확한 조리식풍에 의한 영양소 섭취량을 평가할 수 있도록 하기 위하여 합리적인 영양소섭취량 조사, 영양 평가를 위한 개선책을 제시하고자 끓였다. 대상 시료와 조리법은 시금치(데치기, 끓이기), 배추(끓이기), 콩나물(데치기, 끓이기), 호박(끓이기, 볶기). 당근(끓이기, 볶기), 우엉(조림), 감자(끓이기, 볶기)이었으며, 조리 전 후의 비타민 A(β -carotene), Bl, B2, C, E, 나이아신, 칼슘, 철, 아연, 칼륨, 인, 나트륨의 함량을 분석하여 조리법에 따른 잔즌률을 국하였다. 조리조건별 잔존률을 구한 결과 무기질은 데치기의 경우 조리수를 제거하므로 손실이 있었으나 끓이기, 볶기 등의 조리법에서는 손실이 거의 없었다. 비타민 A와 I는 대부분 80%이상으로 많이 손실되지 않았으며 비타민 Bi은 데치기가 가장 낮았고, 조림, 괄이기, 볶기의 순으로 잔존률이 높았다. 비타민 B2와 나이아신은 비타민 Bi보다는 잔존를이 높은 경향이었다. 비타민 C는 대부 분의 조리법에서 크페 손실되었다. 본 연구의 결과는 합리적이고 정확한 영양소 섭취량 평가를 위한 기초자료로서 기존의 평가방법을 개선 보완하여 영양소섭취량 평가으 과학화에 기여할 것으로 기대된다. In various mutrition activities, the necessary values of nutrient intake were usually calculated from food composition tables which have nutrient contents of raw ingredients and dishes, but Korean food composition tables of dishes were lacking, So we studied todetermine the nutnent retention factors(RF) of vegetables and potatoes by cooking methods. Atfirst, we surveyed cooking methods of vegetables and potatoes, and selected major vegetablesand cooking methods. Selected items and cooking methods were sp.mach(blanching and boiling),cRnese cabbage(boiling), soybean sprout(bBanchlng and boiling), pumpkin(boiling andstir-frying), carlot(boiling and stir-frying), burdock(braising), and potato(boiling and stir-frying)We analyzed 6 vitamins luhich were vitamin A(β-carotene), Bl, B2, C, E, and niacin, and 6minerals which were calciurrl, iron, zinc, potassium, phosphorus, and sodium. The results wereas follows : Minerals almost retained in boiling, stir-frying, except in blanching method, RF ofvitamin A and I were 80% or more. RF of vitandn Bl were decreased in order of sfir-frying,boiling, braising, blanching and the RF of vitamin B2 and niacin were higher than vitandn Bl,RF of the vitamin C were varird in So~90% in all cooking methods

      • KCI등재

        Crystallization and X-Ray Crystallographic Studies of Wild-Type and Mutant Tryptophan Synthase α-Subunits from Escherichia coli

        Se Bok Jang,Mi Suk Jeong 한국분자세포생물학회 2005 Molecules and cells Vol.19 No.2

        The α-subunit of Escherichia coli tryptophan synthase (αTS), a component of the tryptophan synthase α2β2 complex, is a monomeric 268-residues protein (Mr = 28,600). αTS by itself catalyzes the cleavage of indole-3-glycerol phosphate to glyceraldehyde-3-phosphate and indole, which is converted to tryptophan in tryptophan biosynthesis. Wild-type and P28L/Y173F double mutant α-subunits were overexpressed in E. coli and crystallized at 298 K by the hanging-drop vapordiffusion method. X-ray diffraction data were collected to 2.5 Å resolution from the wild-type crystals and to 1.8 Å from the crystals of the double mutant, since the latter produced better quality diffraction data. The wild-type crystals belonged to the monoclinic space group C2 (a = 155.64 Å, b = 44.54 Å, c = 71.53 Å and β = 96.39°) and the P28L/Y173F crystals to the monoclinic space group P21 (a = 71.09 Å, b = 52.70, c = 71.52 Å, and β = 91.49°). The asymmetric unit of both structures contained two molecules of αTS. Crystal volume per protein mass (Vm) and solvent content were 2.15 Å3 Da−1 and 42.95% for the wild-type and 2.34 Å3 Da−1 and 47.52% for the double mutant.

      • SCOPUSKCI등재

        Crystal Structures of Fully Dehydrated Zeolite $Cd_6-A$ and of $Rb_{13.5}-A$, the Product of its Reaction with Rubidium, Containing Cationic Clusters

        Jang, Se-Bok,Kim, Yang,Seff, Karl Korean Chemical Society 1994 Bulletin of the Korean Chemical Society Vol.15 No.3

        The crystal structures of $Cd_6-A$ evacuated at $2{\times}10^{-6}$ Torr and 750$^{\circ}$C (a=12.216(l) ${\AA}$), and of the product of its reaction with Rb vapor (a= 12.187(l) ${\AA}$), have been determined by single-crystal x-ray diffraction techniques in the cubic space group Pm$\bar{3}$m at 21(l)$^{\circ}$C. Their structures were refined to the final error indices, $R_1$=0.055 and $R_2$=0.067 with 191 reflections, and $R_1$=0.066 and $R_2$=0.049 with 90 reflections, respectively, for which I>3${\sigma}$(I). In dehydrated $Cd_6-A$, six $Cd^{2+}$ ions are found at two different threefold-axis sites near six-oxygen ring centers. Four $Cd^{2+}$ ions are recessed 0.50 ${\AA}$ into the sodalite cavity from the (111) plane at O(3), and the other two extend 0.28 ${\AA}$ into the large cavity from this plane. Treatment at 250 $^{\circ}$C with 0.1 Torr of Rb vapor reduces all $Cd^{2+}$ ions to give $Rb_{13.5^-}$A. Rb species are found at three crystallographic sites: three $Rb^+$ ions lie at eight-oxygen-ring centers, filling that position, and ca. 10.5 $Rb^+$ ions lie on threefold axes, 8.0 in the large cavity and 2.5 in the sodalite cavity. In this structure, ca. 1.5 Rb species more than the 12 $Rb^+$ ions needed to balance the anionic charge of zeolite framework are found, indicating that sorption of $Rb^0$ has occurred. The occupancies observed can be most simply explained by two "unit cell" compositions, $Rb_{12^-}A{\cdot}Rb$ and $Rb_{12^-}A{\cdot}2Rb$, of approximately equal population. In sodalite cavities, $Rb_{12^-}A{\cdot}Rb$ would have a $(Rb_2)^+$ cluster and $Rb_{12^-}A{\cdot}2Rb$ would have a triangular $(Rb_3)^+$ cluster. Each of the atoms of these clusters must bind further through a six-oxygen ring to a large cavity $Rb^+$ to give $(Rb_4)^{3+}$ (linear) and $(Rb_6)^{4+}$ (trigonal). Other unit-cell compositions and other cationic cluster compositions such as $(Rb_8)^{n+}$ may exist.

      • SCOPUSKCI등재

        Two Crystal Structures of Ethylene and Acetylene Sorption Complexes of Dehydrated Fully $Ca^{2+}$-Exchanged Zeolite A

        Jang, Se-Bok,Moon, Sung-Doo,Park, Jong-Yul,Kim, Un-Sik,Kim, Yang Korean Chemical Society 1992 Bulletin of the Korean Chemical Society Vol.13 No.1

        Two crystal structures of ethylene (a= 12.272(2) ${\AA}$) and acetylene (a = 12.245(2) ${\AA}$) sorption complexes of dehydrated fully $Ca^{2+}$-exchanged zeolite A have been determined by single crystal X-ray diffraction techniques in the cubic space group, Pm3m at $21(1)^{\circ}C$. Their complexes were prepared by dehydration at $360^{\circ}C$ and $2{\times}10^{-6}$ Torr for 2 days, followed by exposure to 200 Torr of ethylene gas and 120 Torr of acetylene gas both at $24^{\circ}C$, respectively. The structures were refined to final R (weighted) indices of 0.062 with 209 reflections and 0.098 with 171 reflections, respectively, for which I > 3${\sigma}$(I). The structures indicate that all six $Ca^{2+}$ ions in the unit cell are associated with 6-oxygen ring of the aluminosilicate framework. Four of these extend somewhat into the large cavity where each is coordinated to three framework oxide ions and an ethylene molecule and/or an acetylene molecule. The carbon to carbon distance in ethylene sorption structure is 1.48(7) ${\AA}$ and that in acetylene sorption structure 1.25(8) ${\AA}$. The distances between $Ca^{2+}$ ion and carbon atom are 2.87(5) ${\AA}$ in ethylene sorption structure and 2.95(7) ${\AA}$ in acetylene sorption structure. These bonds are relatively weak and probably formed by the electrostatic attractions between the bivalent $Ca^{2+}$ ions and the polarizable ${\pi}$-electron density of the ethylene and/or acetylene molecule.

      • SCOPUSKCI등재

        Crystal Structures of Dehydrated $Ag^{+}\;and\;Ca^{2+}$ Exchanged Zeolite A, $Ag_{3.3}Ca_{4.35}$-A and of Its Ethylene Sorption Complex

        Se Bok Jang,Jong Yul Park,Yunghee Oh Kim,Yang Kim Korean Chemical Society 1993 Bulletin of the Korean Chemical Society Vol.14 No.1

        Two crystal structures of dehydrated $Ag_{3.3}Ca_{4.35}-A ({\alpha} = 12.256(2){\AA})$ and of its ethylene sorption complex (${\alpha} = 12.259(2){\AA}$) have been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at 21(l)$^{\circ}$C. Both crystals were dehydrated at 360$^{\circ}$C and $2{\times}10^{-6}$ Torr for 2 days and one crystal was treated with 200 Torr of ethylene at 24(2)$^{\circ}$C. The structures were refined to final error indices, $R_1$=O.065 and $R_2$ = 0.088 with 202 reflections and $R_1$=0.049 and $R_2$ = 0.044 with 259 reflections, respectively, for which I>3${\sigma}$(I). In these structures, all Ag$^+$ and Ca$^{2+}$ ions are located on two and three different threefold axes associated with 6-ring oxygens, respectively. In $Ag_{3.3}Ca_{4.35}-A{\cdot}6.65\;C_2H_4,\;3.3\;Ag^+\;and\;3.35\;Ca^{2+}$ ions are recessed 1.09 ${\AA}$ and 0.21 ${\AA}$, respectively, into the large cavity from the (111) plane at O(3). Each Ag$^+$ and Ca$^{2+}$ ion in the large cavity forms a complex with one $C_2H_4$</TEX molecule. Distances between Ca$^{2+}$ ions and ethylene molecules are longer than those between Ag$^+$ ions and ethylene molecules.

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