Volume 8 Issue 2

  1. Pyun, Hyung-Chick;Kim, Jae-Rock 39
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    As the bromination method with $Br_2^{82}$ for the synthesis of 5-bromouracil-$Br^{82}$ gave products with considerable impurities, e. g. uracil etc. an attempt to produce pure one by isotopic exchange method was performed. Bromide-82 ion such as $NH_4Br^{82}$ or $HBr^{82}$ undergoes no isotopic exchange with 5-bromouracil-Br. However, isotopic exchange between $NH_4Br^{82}$ and $Br_2$, and between $Br_2^{82}$ and 5-bromouracil-Br were too fast to determine the rate. The result indicated that this method can be used in the production of pure 5-bromouracil-$Br^{82}$. It was also found that the use of reducing agent to maintain $Br^{82}$ as bromide form was unnecessary on $NH_4Br^{82}$ production from reactor.
  2. Lee, Ik-Choon 43
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    Quenching constants, q, determined for N,N-dimethylanilines by liquid scintillation counting indicate that the quenching involves an energy transfer process to these compounds causing strong n-${\pi}$ interaction within the quencher molecule, which is then followed by an non-radiative degradation of the excitation energy to ground state.
  3. Kim, You-Sun;Chae, Song-Cha 47
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    展開한 페이퍼크로마토그램을 韓國 Triga-Mark-Ⅱ 硏究用 原子爐의 뉴마딕튜부施設(中性子線束; 1.5{\times}$10^{12}n/cm^2$, sec)을 利用하여 照射하여 본 結果 크로마토그램上에 展開된 스폿트(spot)를 定性的으로 確認할 수 있었다. 有機하로겐 化合物(크로로酸, 크로로에스테르, 沃化物, 及 弗化物)에 있어서 一般發色法으로서는 明確한 着色스폿트(spot)를 나타내지 못한 것에 있어서도, 이 方法으로서 展開된 스폿트를 明確히 區別할 수 있었다. 濾紙成分의 放射化에 依한 誤差를 減少시키기 爲하여 濾紙두께 補正 及 放射化度 補正을 硏究한 結果, 濾紙두께 補正 及 放射能崩壞 補正法을 究明하였으며, 이 方法으로 스폿트를 放射化하여 定性分析하는데 좋은 結果를 얻을 수 있었다. 有機하로겐化合物의 分析 及 確認에 있어서의 이 方法의 效用性에 關하여 論議하였다. 濾紙相으로는 正常相 及 逆相을 함께 使用하였다.
  4. Choi, Hyung-Sup;Park, Won-Koo 57
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    It was verified at Part Ⅰ of this investigation that there is a minimum wettability between molten iron and graphite, which was preliminarily coated with magnesium, and thus the spheroidization of graphite might have resulted from the lack of wettability between magnesium-adsorbed graphite and iron matrix. Being continued from the last work, the wettability between pure iron and graphite, coated with the various thickness of cerium, are measured at melting point of pure iron in vacuum and 200 mmHg argon gas atmosphere. The result indicates the presence of a minimum wettability at a critical thickness of cerium film as was proved in the case of magnesium. The experimental analysis shows that, the minimum wettability could be attributed entirely to a minimum work of adhesion between liquid iron and graphite at a critical concentration of cerium in the iron-graphite interface.
  5. Kim, Tong-Yup;Cha, Ki-Won;Park, Kee-Chae 62
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    The cation exchange chromatographic studies for the analysis of transition metals have been described. The quantitative separation of a mixture of Fe(Ⅲ), Cu(II), Zn(II), Ni(II), Cd(II), Co(II) and Mn(II) has been obtained by elution, through a 28cm column of the resin, Dowex 50 ${\times}$ 4 (100∼200 mesh), using 0.45 M $NaNO_3$+0.05 M Na-tartrate solution as eluent, starting with the eluent of pH 3.5, followed stepwise by pH 4.0 and 4.5. A comparison between the calculated and the observed peak positions in the elution curve has been shown. The relative stability constants for tartrate complexes of some transition metals have been calculated by using distribution ratios obtained in this separation procedure.
  6. Jhon, Mu-Shik;Chang, Sei-Hun 65
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    H. Eyring등에 의하여 제안된 액체구조에 관한 이론에 따라서 액체의 partition function을 정하였다. parameter $E_S$, $V_S$, ${\theta}$, a는 앞서 저자들에 의해 제안된 방법에 의하여 정하였고, 이렇게 정해진 partition function을 써서 액체의 몰부피, 증기압, 한계점. 증발엔트로피 및 표면장력등을 계산한 결과 실측치와 잘 맞는 값을 얻었다.
  7. Pak, Hyung-Suk;Chang, Sei-Hun 68
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    물은 용융점, 끓는점, 용융열 및 증발열등의 수소와 6족원소와의 화합물의 성질로부터 예측되는 값보다 훨씬 크고, ice-I녹을 때 부피의 감소가 일어나는 등 특이한 성질을 가지고 있다. 이와같은 성질들을 정량적으로 설명하려고 지금까지 많은 연구자들이 노력해왔다. 저자들은 물의 큰 표면자유에네르기와 용융시의 특수한 부피변화로 미루어 물의 구조모델을 다음과 같이 생각하였다. 즉, 얼음이 용융함에 따라 분자크기의 이동성 빈자리가 도입되면 물의 큰 표면에네르기 밀도로 말미암아 빈자리 주위의 물분자는 촘촘한 배열을 가지게 되면 빈자리에서 떨어져있는 분자는 ice-I의 구조를 가질것으로 생각된다. 빈자리 주위의 분자가 빈자리에 뛰어 들어갈 때는 이동자유도를 지니게 될 것이다. 저자들은 H. Eyring의 액체구조이론을 써서 물의 liquid partition function을 위에 말한 바와 같이 구조모델로부터 유도하고 물의 증기압, 용융 및 증발엔트로피 등 여러가지 열역학적 성질 및 몰부피를 계산하여 실측치와 좋은 일치를 얻었다.
  8. Kim, Tae-Bong;Hahn, Bo-Sup;Hahn, Sang-Heyun;Kee, Ryong-Suk 75
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    It was confirmed that korean scabby barley during the summer of 1963 was infected with Gibberella zeae. Feeding experiments showed that the diseased grain was toxic and induced emesis in pigs. The concentrated extracts which contained the emetic principle were prepared by refluxing the grain with methanol or water for 5 hours and then concentrating the filtrates and the washing in vacuum. Animal tests proved that methanol extraction for the emetic principle was more effective than extraction with water.
  9. Kim, Tae-Bong;Hahn, Bo-Sup;Hahn, Sang-Heyun 78
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    In this report, some practical problems that are concerned with the infected barley were examined. Most of the toxic substance is present in the bran. It was almost impossible to remove the toxic substance with water or methanol completly, however, we found it is effectively eliminated by soaking the whole grain with 2%, calcium hydroxide suspension for 24 hours. As a detoxifying agent, kieselguhr was very effective; the grain mixed with little amounts (0.4-0.5%) of kieselguhr may be used as an animal feed.
  10. Kim, Tae-Bong;Hahn, Bo-Sup 82
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    It has been pointed out that various substances such as "toxoalbumin", glycoside, choline or readily hydrolysable choline derivatives, alkaloid, lysolecithine etc. are associated with the toxicity of the infected grain. But animal tests and analysis of paper chromatography by author's indicated that a basic substance present in the concentrated extracts from the grain may neither be acetylcholine, betaine, nor choline. This problem still have to be examine further.
  11. Kim, Tae-Bong;Hahn, Bo-Sup 85
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    Alloxan에 의한 Amino acids의 spot test에 있어서, alloxan수용액에 lactose를 가해주면, alloxan 자신의 착색을 막을 수 있다. lactose를 포함하는 alloxan수용액은 매우 안정하여서, 실온에서 수 개월 동안 두어도 착색되지 않으며, lactose의 존재로 말미암아, alloxan과 amino acids와의 색반응은 조금도 영향을 받지 않았다. 이시약에 의한 amino acids의 spot test법은 ninhydrin에 의한 spot test보다 예민하고, 또 alloxan 또는 dimethylalloxan을 발색약으로 사용하는 paper chromatography법에 비해, proline (1 ${\gamma}$), hydroxyprolin (5 ${\gamma}$)를 확인할 수 있다는 장점을 가지고 있다.
  12. Chung, Koo-Soon;Lee, Chul 88
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    모나자이트中의 스칸디움含量을 더욱 簡便히 決定할 수 있도록 改良한 放射化分析法을 記述하였다. 즉 熱中性子束($10^{12}n/cm^2/sec$)에 照射된 試料에 스칸듐擔體와 黃酸을 넣고 加熱融解한 後 물로 稀釋한 試液에 암모니아水를 加하여 稀土類元素를 沈澱分離하였다. 沈澱을 鹽酸에 녹힌 다음 티오시안酸암모늄을 넣어 스칸듐을 에테르로 抽出하였다. 스칸듐의 化學的 回收率은 스칸듐을 만델린酸으로 沈澱시켜서 重量分析法에 依하여 決定하였다. 本分離法에 依한 스칸듐의 分離能과 共存元素의 放射能의 妨害與否는 이온交換樹脂를 使用하여 스칸듐을 分離한 結果와 比較檢討하였다. 스칸듐의 放射能은 Gamma-scintillation spectrometry 에 依하여 計測하였고 韓國産 모나자이트에는 約 12 p.p.m.의 스칸듐의 含有되어 있음을 알았다.