Journal of Computer Chemistry, Japan
Online ISSN : 1347-3824
Print ISSN : 1347-1767
ISSN-L : 1347-1767
6 巻 , 2 号
選択された号の論文の6件中1~6を表示しています
  • 神部 順子, 長嶋 雲兵, 山内 あい子, 青山 智夫
    2007 年 6 巻 2 号 p. 91-102
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    OECDによるドナウ川の水質データの経年変化に関し,欠測データを含むデータの解析が可能な多階層型ニューラルネットワークシミュレーション(CQSAR)法を用いて,欧州の河川再自然化政策等による河川の水質浄化の有効性およびダム建設の影響を検討した.
    ドイツ圏で施行されている河川再自然化や水質浄化政策はT-P値の改善にはあまり効果がなかったが,DO,BOD値を改善していた.特に,ドナウ川のハンガリー流域でのBOD値に浄化傾向がみられた.ドナウ川のBOD値から自然浄化作用が河川浄化策の施行により回復してきていると判断できた.
    スロヴァキアとハンガリー間のドナウ川に設けられたダム(ガブチコボ・ナジュマロシュ・ダム)の影響は,DO値は悪化される傾向にあり,逆にBOD値は改善される傾向にあった.また,ダム建設によりダム下流のドナウ川のハンガリー流域でのDO値やBOD値が,ダム上流域の水質と関係しなくなったことが明らかになった.
  • Tomoo AOYAMA, Takatoshi HIGUCHI, Umpei NAGASHIMA
    2007 年 6 巻 2 号 p. 103-108
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    An approximate orthogonalization method called "pseudo-orthogonalization" was derived here from the Schmidt orthogonalization in a partial space. Precision of the orthogonalization is decimal 2 digits when the partial space of 1/3 of the Schmidt orthogonalization is used. The speed-up ratio is 3.3 with 1000 vectors of 1500th dimension. Although the pseudo-orthogonalization is high-speed, the precision is inadequate for general numerical calculations. Two possible approaches to improve this precision were considered: (a) introducing a band structure in the vectors, and (b) restricting the sign of the vector elements. These approaches improved the precision by a factor of 2.1 and 1.5, respectively, without increasing the CPU time.
    To demonstrate the applicability of this high-speed pseudo-orthogonalization for large-scale calculations, we coded a complex-form of it into the SCF part of the Car-Parrinello method. In calculations of the total energy for bulk-silicon, the difference in total energy calculated using the pseudo-orthogonalization and that using the Schmidt orthogonalization was less than O(-5) [a.u.]. Based on this accuracy, this pseudo-orthogonalization can be used to speed-up the Car-Parrinello method when it is applied to large-scale calculations.
  • 古後 義也, 時田 澄男, 西本 吉助
    2007 年 6 巻 2 号 p. 109-116
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    チオフェン系アゾ色素は対応する置換アゾベンゼンより長波長側に吸収を示す。この現象(深色性)を明らかにする目的でベンゼン、チオフェン、フラン、ピロール、シクロペンタジエンおよびこれらのアザ置換体からなるアゾ化合物について量子化学計算をおこなった。まず、AM1、PM3、DFT計算によりそれぞれの安定配座を推定した。ついでチオフェン系アゾ化合物について硫黄原子の3d-AOを含めた場合と含めない場合のCNDO/S計算を行い、最長波長吸収帯に対する3d-AOの寄与は無視し得ることが確認された。さらに、CNDO/S法およびTD-DFT法によりスペクトル計算をおこなった。その結果、チオフェン系アゾ化合物が特異的に深色性を示すのではなく五員環系アゾ色素に共通した特性であることが示唆された。
  • Kumiko SAKAMOTO, Aiko YAMAUCHI, Mikio SASAKI, Hiroshi CHUMAN
    2007 年 6 巻 2 号 p. 117-122
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    Many efforts have been devoted to the development of computer-aided prediction of drug toxicity over the decades, but at present, systems and programs available for predicting teratogenicity from chemical structures do not always give satisfactory answers yet, mainly because of the complex and unknown mechanism of reproductive and developmental toxicity. We developed a novel algorithm and implemented in the program "SimScore" to evaluate quantitatively the structural similarity score of a target compound with the teratogenic drugs which are defined as serious human teratogens by the United States Food and Drug Administration. In SimScore, a molecular structure is divided into its skeletal and substituent parts in order to perform similarity comparison for these parts independently. This idea is based on that compounds with the same or similar skeleton show a similar biological activity, but their activity strengths depend on the variation of substituents. We demonstrated the usefulness of SimScore by applying it to an example.
    SimScore will be used in our web-based information system about teratogenicity to predict the potential risk of query compounds.
  • Hiroshi SAKIYAMA
    2007 年 6 巻 2 号 p. 123-134
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    MagSaki(A) software was developed for the magnetic analysis of dinuclear high-spin cobalt(II) complexes. This software performs magnetic analysis to determine magnetic parameters using five types of theoretical susceptibility equations. A characteristic feature of the software is that the exchange interaction can be treated anisotropically whereas the previous MagSaki software treats the exchange interaction isotropically.
  • Tomoo AOYAMA, Junko KAMBE, Aiko YAMAUCHI, Umpei NAGASHIMA
    2007 年 6 巻 2 号 p. 135-144
    発行日: 2007年
    公開日: 2007/08/28
    ジャーナル フリー
    A model for purification mechanisms in a river was proposed to express changes in the values of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), T-N (Total Nitrogen), and T-P (Total Phosphorous) as the combination of inflows, streams, and weirs. Because expressions for these functions are unknown, the model first constructs multi-layer neural-network functions based on observations, and then uses the derivatives to evaluate the cause and effect of pollution.
    For data of the Tamagawa through Tokyo, Japan in 2002, the model suggested that the cause of pollution is inflows from sewage, the stream of the Tamagawa has purification functions for COD and T-P, but has little ability for T-N, and the weirs have purification for COD, but have no purification for T-N and T-P. The results from the model were consistent with common sense for the water quality, and thus, there was no failure in the model.
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