• Journal of the Korean Chemical Society
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• v.31 no.2
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• pp.143-152
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• 1987

$\pi$-Binding energy of the 153 kinds of unsaturated acyclic polyenes and unsaturated cyclic polyenes has been calculated by the Kier's Molecular Connectivity Index. An excellent linear correlation is found between HMO $\pi$-binding energy and $\pi$-binding energy calculated by the Kier's Molecular Connectivity Index. In either class of unsaturated acyclic hydrocarbons and unsaturated cyclic hydrocarbon, the regression analysis reveals a highly significant linear correlation between $E_{\pi}$ and $^1{\chi}^v$ (the first order valence connectivity index).

• Kyungpook Mathematical Journal
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• v.57 no.2
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• pp.211-222
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• 2017

In this paper, we consider three inverse eigenvalue problems for a special type of acyclic matrices. The acyclic matrices considered in this paper are described by a graph called a broom on n + m vertices, which is obtained by joining m pendant edges to one of the terminal vertices of a path on n vertices. The problems require the reconstruction of such a matrix from given partial eigen data. The eigen data for the first problem consists of the largest eigenvalue of each of the leading principal submatrices of the required matrix, while for the second problem it consists of an eigenvalue of each of its trailing principal submatrices. The third problem has an eigenvalue and a corresponding eigenvector of the required matrix as the eigen data. The method of solution involves the use of recurrence relations among the leading/trailing principal minors of ${\lambda}I-A$, where A is the required matrix. We derive the necessary and sufficient conditions for the solutions of these problems. The constructive nature of the proofs also provides the algorithms for computing the required entries of the matrix. We also provide some numerical examples to show the applicability of our results.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.437-446
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• 2014

The dihydroxylation reaction of allylic amines is a facile and useful synthetic method to obtain amino diol structures that are widely found in lots of biologically important natural products. This review will focus on the recent methods of both substrate-controlled and ligand-controlled dihydroxylation reactions of acyclic allylic amines. In addition, several applications of the diastereoselective dihydroxylation methods to asymmetric syntheses of natural products are presented.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.680-683
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• 1997

Fieldbus system should be designed by considering the number of sensors/actors(actuators+ controllers) and their sampling times. But the number of sensors/actors and which are connected to the network bus can be varied by addition and/or fault of the field devices. That variation decreases the efficiency of system which is off-line designed optimally. This paper proposes an algorithm that ensures transmission of cyclic data even though there is the number change in the field devices. We assign the different weight values to cyclic data and acyclic data. By simulation and experiment, the cyclic and acyclic data are processed via the proposed network, and the results are compared with those of the Profibus system. It is shown that the proposed algorithm is more robust with the uncertainties of the field devices of the control system.

• Management Science and Financial Engineering
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• v.13 no.1
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• pp.121-126
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• 2007

Among many graphs, directed acyclic graph(DAG) attracts many researchers due to its nice property of existence of topological sort. In some classic graph problems, it is known that, if we use the aforementioned property, then much efficient algorithms can be generated. So, in this paper, new algorithm for the all-pairs shortest path problem in a DAG is proposed. While the algorithm performing the iteration, it identifies the set of essential arcs which requires in a shortest path. So, the proposed algorithm has a running time of $O(m^*n+m)$, where m, n and $m^*$ denote the number of arcs, number of node, and the number of essential arcs in a DAG, respectively.

• YAKHAK HOEJI
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• v.33 no.6
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• pp.361-364
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• 1989

The Synthesis of acyclic derivatives of ribavirin (2'-azido and halo seco derivatives) for the development of new antiviral agents is described. These acyclic nucleosides are synthesized from ribavirin by the method of ring opening reaction of sugar moietry.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.1-6
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• 2017

The conductivity of the electrolyte used plays a critical role in the optimization of the performance of electrochemical double layer capacitors. However, when the difference in the conductivities of different electrolytes is not significant (only 10-20%), the conductivity has little effect on the capacitance. On the other, unlike the conductivity and viscosity of the electrolyte, the cation size directly influences the capacitance. Cyclic ions have a smaller effective radius than that of the corresponding acyclic ions because the acyclic alkyl groups have a greater number of conformational degrees of freedom, such as the rotational, bending, and stretching modes. Consequently, because of the smaller effective size of the cyclic ions, cells containing electrolytes with such ions exhibit higher capacitances than do those with their acyclic counterparts.

• Archives of Pharmacal Research
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• v.22 no.2
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• pp.225-227
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• 1999

A new acylcic deterpene (1) and a known acyclic diterpene 12(S)-hydroxygeranyleraniol (2) were isolated form the aerial parts of Carpesium divaricatum. The structure of 1 was determined to be (2E, 10E)-1, 12-dihydroxy-18-acetoxy-3,7,15-trimethylhexadeca-2,10,14-triene (1) on the basis of spectroscopic studies. Compounds 1 and 2 exhibited cytotoxicity against cultured human tumor cell lines, A549, SK-OV-3, SK-MEL-2, XF498, and $HCT_{15}$, with $ED_{50}$ values ranging from 4.3-10.2 ${\mu}g/ml$ and 4.1-8.3 ${\mu}g/ml$, respectively.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.66-70
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• 1995

The soil humic acid was subdivided into four subfractions by molecular weight (F1: >100.000 dalton; F2: >100.000 dalton; F3: >10.000 dalton; F4: >2.000 dalton) using MP-dual hollow fiber ultrafiltration system. The characterization using IR, 1H and 13C NMR spectroscopy, showed similar spectroscopic features of HA, demonstrating that the bulk properties of HA subfractions are very similar to one another. IR spectral data showed a decrease in polysaccharide contents and increase in carboxylate functionality as molecular weight become smaller.functions. The structure of (NO) can be described by two interactions (N${\cdot}{\cdot}{\cdot}$N, N${\cdot}{\cdot}{\cdot}$O). One is the ONNO structure with an (N${\cdot}{\cdot}{\cdot}$N) interaction. In this structure, acyclic cis-ONNO with $C_{2v}$-symmetry, acyclic trans-ONNO with $C_{2h}$, and cyclic ONNO with trapezoidal structure ($C_{2v}$) are optimized at the MP2 level. The other structure is the ONON structure with an (N${\cdot}{\cdot}{\cdot}$O) interaction. In the structure, acyclic cis-ONON with Cs$^{-symmetry}$ and cyclic ONON of the rectangular ($C_{2h}$), square $(D_{2h})$, rhombic $(D_{2h})$, and parallelogramic $(D_{2h})$ geometries are also optimized. It is found that acyclic cis-ONNO $(^1A_1$) is the most stable structure and cyclic ONNO ($^3A_1$) is the least stable. Acyclic trans-ONNO ($^3A_1$) with an (N${\cdot}{\cdot}{\cdot}$N) interaction, acyclic trans-ONON and bicyclic ONON $(C_{2v})$ with (N${\cdot}{\cdot}{\cdot}$O) interaction, and acyclic cis- and trans-NOON with an (O${\cdot}{\cdot}{\cdot}$O) interaction can not be optimized at the MP2 level. Particularly, acyclic trans-ONNO with $C_{2h}$-symmetry can not be optimized at the CCSD(T) level. Meanwhile, acyclic NNOO ($^1A_1$, $C_s)$ and trianglic NNOO ($^1A_1$,$C_{2v})$ formed by the (O${\cdot}{\cdot}{\cdot}$N) interaction between $O_2$and $N_2$are optimized at the MP2 level. The binding energies and the relative energy gaps among the isomers are found to be relatively small./sec. Spiral CT scans during the arterial phase were obtained 35 seconds after the injection of contrast medium. CT findings of 78 lesions less than 4cm in diameter were correlated with angiographic findings. Results : The attenuation of lesions was high(n = 69), iso(n = 5), and low(n = 4) compared with liver parenchyma during the arterial phase of spiral CT. In lesions with high-, iso-, and low-attenuation during the arterial phase of spiral CT, hypervascularity on angiograms was found in 63 of 69(91.3%), three of five(60%), and three of four lesions(75%), respectively. Six lesions with high-attenuation on the arterial phase of spiral CT were not seen on angiography. Two iso-attenuated and one low-attenuated lesion were hypovascular on angiograms. Conclusion : The results of this study suggest that with some exceptions there was good correlation between the arterial phase of spiral CT and angiography.

• Journal of Photoscience
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• v.12 no.2
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• pp.63-66
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• 2005

The azomethine ylide forming photoreaction has been explored by probing the excited state chemistry of several N-trimethylsilylmethyl substituted cyclic and acyclic imides and amide analogs. N-[(Trimethylsilyl)methyl]-N-mesylbenzamide (5) undergoes the excited state C to O silyl migration reaction to produce azomethine ylide intermediate 13. This ylide undergoes electrocyclization to form transient aziridine intermediate 14 which react further by ring opening to generate N-phenacylamine product 10. On the other hand, photolysis of N-[N-mesyl-N-(trimethylsilyl)methyl]aminoethyl-N-mesylbenzamide (8) brings about desilylation resulting in the production of dimer 17.