• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.144-149
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• 1990

Conformational free energy calculations using an empirical potential function (ECEPP/2) and the hydration shell model were carried out on the sulfonylurea herbicides of bensulfuron methyl (Londax) and metsulfuron methyl (Ally). The conformational energy was minimized from starting conformations which included possible combinations of torsion angles in the molecule. The conformational entropy of each conformation was computed using a harmonic approximation. To understand the hydration effect on the conformation of the molecule in aqueous solution, the hydration free energy of each group was calculated and compared each other. It was found that the low-free-energy conformations of two molecules in aqueous solution prefer the overall folded structure, in which an interaction between the carbonyl group of ester in aryl ring and the first amido group of urea bridge plays an important role. From the analysis of total free energy, the hydration and conformational entropy are known to be essential in stabilizing low-free-energy conformations of Londax, whereas the conformational energy is proved to be a major contribution to the total free energy of low-free-energy conformations of Ally.

• International Journal of Computer Science & Network Security
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• v.24 no.1
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• pp.45-51
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• 2024

The subject of navigation has drawn a large interest in the last few years. The navigation within a city is to find the path between two points, source location and destination location. In many cities, solving the routing problem is very essential as to find the route between different locations (starting location (source) and an ending location (destination)) in a fast and efficient way. This paper considers streets with diagonal streets. Such streets pose a problem in determining the directions of the route to be followed. The paper presents a solution for the path planning using the reconfigurable mesh (R-Mesh). R-Mesh is a parallel platform that has very fast solutions to many problems and can be deployed in moving vehicles and moving robots. This paper presents a solution that is very fast in computing the routes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.3
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• pp.16-21
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• 1976

Transparent eloctroaes of polycrystalline till-oxide films doped with antimony are prepared on the substrate of microscopic cover g1ass by modified spray method and from SnCl4 Solution. Their electrical and optical properties are investigated in relation to the surface temperature of the substrate glass and to antimony concentration in the starting materials. The sheet.resiststrace of the film electrodes and transmittance for incandescent light depen on tile antimony concentration and surface temperature of substrates at the time of making films. The transmittance increases with decrease of sheet resistance of the film. The optimum sheet.resistance was obtianed in the case of the antimony concentration 0.6(%) approximately , and the max. transmittance was 93(%).

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.104-114
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• 1994

ZrO2 fibers were fabricated by means of the Sol-Gel process using Zr(O-nC3H7)4-H2O-C2H5OH-HNO3 solution as a starting material. The optimum experimental parameters such as molar ratio of starting materials, concentration, temperature, viscosity, the amounts of stabilizer and the pH of solution were determined. The experimentally determined optimum variables which produce good ZrO2 fibers were used to manufacture the Y2O3-and CaO-ZrO2 fibers. The amounts of Y2O3 and CaO were varied within the range from 1.5~5 mol% and 3~15 mol% respectively. The phase transformation and microstructural evolution of the fabricated ZrO2 gel fibers were investigated after heat treatments up to 120$0^{\circ}C$ by X-ray diffraction, Raman microprobe spectroscopy, SEM, and specific surface area and pore volume measurements. From the analysis of X-ray diffraction and Raman spectra, the phase of heat treated Y2O3-and CaO partially stabilized ZrO2 gel fibers(Y2O3:2.5~3 mol%, CaO:6~9 mol%) were identified as a tetragonal phase up to 100$0^{\circ}C$. The maximum tensile strength of 2.5Y2O3-97.5ZrO2 and 6CaO-94ZrO2 (in mol%) fibers heat treated at 100$0^{\circ}C$ for 1 hr was found be 1.3~2 GPa with diameters of 10~20 ${\mu}{\textrm}{m}$.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.16-22
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• 2019

After Dantzig and Rasmer introduced Vehicle Routing Problem in 1959, this field has been studied with numerous approaches so far. Classical Vehicle Routing Problem can be described as a problem of multiple number of homogeneous vehicles sharing a same starting node and having their own routes to meet the needs of demand nodes. After satisfying all the needs, they go back to the starting node. In order to apply the real world problem, this problem had been developed with additional constraints and pick up & delivery model is one of them. To enhance the effectiveness of pick up & delivery, hub became a popular concept, which often helps reducing the overall cost and improving the quality of service. Lots of studies have suggested heuristic methods to realize this problem because it often becomes a NP-hard problem. However, because of this characteristic, there are not many studies solving this problem optimally. If the problem can be solved in polynomial time, optimal solution is the best option. Therefore, this study proposes a new mathematical model to solve this problem optimally, verified by a real world problem. The main improvements of this study compared to real world case are firstly, make drivers visit every nodes once except hub, secondly, make drivers visit every nodes at the right time, and thirdly, make drivers start and end their journey at their own homes.

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.333-337
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• 2005

In order to improve the performance of green emitting phosphors for plasma display panel, the $Zn_2SiO_4:Mn,Al$ phosphors were synthesized using sol-gel technique and studied using SEM and VUV photoluminescence spectrometer. pH values of the starting solutions (pH = 0.5$\~$2.34) were controled by HCl as the catalysis of hydrolysis and wet gels were dried at $80^{\circ}C$ and $120^{\circ}C$, respectively. We investigated the effects of pH and drying temperatures during sol-gel processes. The results indicated that the phosphor prepared at pH = 1 showed the maximum emission intensity in both drying conditions and the effect of pH of the starting solution on morphology were increased with particle size as HCl and phosphor dried at high temperature showed more spherical and smaller particles than at low.

• Advances in nano research
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• v.2 no.2
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• pp.77-88
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• 2014

Solvothermal treatment of late transition metal acetylacetonates in a novel medium composed either of pure acetophenone or acetophenone mixtures with amino alcohols offers a general approach to uniform hydrophilic metal nanoparticles with high crystallinity and low degree of aggregation. Both pure metal and mixed-metal particles can be accesses by this approach. The produced materials have been characterized by SEM-EDS, TEM, FTIR in the solid state and by Nanoparticle Tracking Analysis in solutions. The chemical mechanisms of the reactions producing nanoparticles has been followed by NMR. Carrying out the process in pure acetophenone produces palladium metal, copper metal with minor impurity of $Cu_2O$, and NiO. The synthesis starting from the mixtures of Pd and Ni acetylacetonates with up to 20 mol% of Pd, renders in minor yield the palladium-based metal alloy along with nickel oxide as the major phase. Even the synthesis starting from a mixed solution of $Cu(acac)_2$ and $Ni(acac)_2$ produces oxides as major products. The situation is improved when aminoalcohols such as 2-aminoethanol or 2-dimethylamino propanol are added to the synthesis medium. The particles in this case contain metallic elements and pairs of individual metals (not metal alloys) when produced from mixed precursor solutions in this case.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.6
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• pp.35-42
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• 2019

In this paper, we analyze the practical problems of the regenerative start method proposed to improve the starting characteristics of the TBM(Tunnel boring machine)system and propose a solution. In order to solve the speed ripple problem in the previous research results, we first analyze the problems occurring in the system and propose a method to compensate for them. By applying the improved method to the actual system, we compared the results with the conventional system and verified the effect of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.52-63
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• 1998

In this paper, several improvements to a copy network proposed previously for multicast packet switching are described. The improvements provide a solution to some problems inherent in multicasting. The input fairness problem caused by overf low is solved by a dynamic starting point decider(DSD), which can calculate running sums of copy requests starting from any input port. The starting point is changed adaptively in every time slot based on both the fill level of the input buffers in current time slot and the overflow situations of the previous time slot. Using the fill level of the conventional network. The DSD also provides the function of regulating overall copy requests according to the amount of input traffics. This is an essential function in improving overall throughputs of the copy networks. The throughput of a multicast switch can be improved substantially if partial service of copy request is implemented when overflow occurs. Call-splitting can also be implemented by the DSD in a straightforward manner. The hardware for the DSD is derived with the objective of simple architectures for the high speed operation. Simulation study of the copy network under various traffic conditions is presented to evaluate its performance.

• Journal of the Korean Ceramic Society
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• v.36 no.9
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• pp.893-900
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• 1999

Silica films were prepared on Si single crystal substrates by sol-gel process using TEOS as starting materials. Films were fabricated by a spin coating technique. Sol solutions were prepared by varying the compositions of CH3OH, H2O and DMF with fixed molar ratio of TEOS=1, HCl=0.05(mol). Wetting behavior viscosity of solutions gelation time thickness of films and cracking behavior were investigated with the various solution compositions. Wetting behaviors of solutions depended on the solution compositions mixing method and mixing rate. The optimum composition of sol was TEOS : DMF ; CH3OH: H2O :HCl=1:2:4:4:0.05(mol) and the mixing rate of solution was optimized at 1 ml/min. Viscosity of solutions were controlled by choosing a reaction time(elapsed time after mixing) at a room temperature so that we could get up to 800nm thick film The surface roughness was getting poor when thickness of films was thicker than 500nm. Thickness of coated films were increased with decreasing amount of CH3OH. The best surface roughness was obtained at the content of CH3OH 4 mol. The shortest gelation time was obtained with the content of CH3OH 8 mol. Crack-free filkms were fabricated when sintered at 500$^{\circ}C$ for 1 hr with heating rate of 0.6$^{\circ}C$/min.