• Journal of Positioning, Navigation, and Timing
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• 제7권4호
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• pp.235-243
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• 2018

Conventional Real Time Kinematics (RTK) collect measurements in stationary state for several minutes to resolve the integer ambiguity in the carrier phase measurement or resolve the integer ambiguity on the move assuming low maneuvering movement. In this paper, an On The Move-RTK (OTM-RTK) technique that resolves the integer ambiguity on the move for fast and precise positioning of ground vehicles such as high maneuvering vehicles was proposed. The OTM-RTK estimates the precise amount of movement between epochs using the carrier phase measurements acquired on the move, and by using this, resolves the integer ambiguity within a short period of time by evaluating the integer ambiguity candidates for each epoch. This study analyzed the integer ambiguity resolution performance using field driving experiment data in order to verify the performance of the proposed method. The results of the experiment showed that the precise trajectory including the initial position bias can be obtained prior to resolving the integer ambiguity, and after resolving the integer ambiguity on the move, it was possible to obtain the bias-corrected precise position solution. It was confirmed that the integer ambiguity can be resolved by collecting measurements of about 10 epochs from the moving vehicle using a dual frequency receiver.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1955-1961
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• 2012

In this work, the reactions of carbamyl and thiocarbamyl halides with $NH_3$ were studied in the gas phase at the MP2(FC)/6-31+G(d) level of theory. Single point calculations were performed at the QCISD/6-311+G(3df,2p) to refine the energetics. The reaction mechanisms were also studied in aqueous solution. The structures were fully optimized at the CPCM-MP2(FC)/6-31+G(d) and refined by a single point CPCM-QCISD/6-311+G(3df,2p) calculations. The reaction mechanisms for the title compounds were compared with those for the acetyl and thioacetyl halides. The lower reactivity of carbamyl (and thiocarbamyl) groups was explained by comparing the C=O and C=S ${\pi}$-bond strengths as well as resonance contributions in the ground state.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.539-542
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• 1999

In this study, acrylate salt material of new chemical composition for injection grouting was prepared in the state of aqueous solution, and the chemical and physical properties of the material were investigated. The gelation time of the material was freely controllable through the control of added catalysts amount. As the viscosity of the material was very low (2∼3cps), its injection efficiency was expected to be very excellent. The variation of its viscosity plotted with the process of gelation revealed that the efficiency of its penetration into the ground soil was very excellent. The LD$\sub$50/ test on white mouse verified the toxicity of the material was very slight and substantially negligible. The grouting effect using the material was examined through field case histories.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.73-78
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• 1992

A stochastic simulated anneal ins (SSA) is a recent approach to the solution of problems characterized by large number of interacting degrees of freedom. SSA simulates the degrees of freedom in a problem in a such a way that they are a collection of atoms slowly being coolded into a ground state which would correspond to the stationary point of the problem. In this paper, for a randomly disturbed current design, SSA optimization technique is used, which establishes a probabilistic criterion for acceptance or rejection of current design and iteratively improves it to arrive at a stationary Point at which critical temperature is reached. Simple truss optimization problem which consider as their constraints only the tensile and compressive yielding strength of the members are tested using SSA. Satisfactory results are obtained and some discussions are given for the behavior of SSA on the tested truss structures.

• 천문학회보
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• 제39권1호
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• pp.27-27
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• 2014

The past three decades have witnessed a renaissance in the field of extragalactic globular clusters (GCs). GC systems have now been investigated in galaxies ranging from dwarfs to giants and spanning all the morphological types. Detailed studies of GCs provide strong constraints on galaxy formation that can be obtained in the near-field. In this talk I will review some of the pivotal studies performed with the HST and large ground-based telescopes and state-of-the-art simulations. Also, I will attempt to introduce my new solution to a long-standing puzzle in this field----the origin of GC bimodality in color. I will show that the theory gives a simple, cohesive explanation for the key observations of extragalactic GCs. The implication of the results will be discussed in the context of formation of GC systems and their parent galaxies.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1757-1763
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• 2004

A new series of nickel(II), cobalt(II)/(III) and copper(II) complexes of 14, 15 and 16-membered of macrocyclic ligands have been prepared and characterized by elemental analyses, IR, UV-VIS and $^1H-NMR$ spectra, magnetic susceptibilities, conductivities, DTA and ESR measurements. Molar conductances in DMF solution indicate that, the complexes are nonelectrolytes except (9-12) complexes. The electronic spectra show that, all complexes are square planar or distorted octahedral geometry. The ESR spectra of solid complexes (4), (8) and (11) show square planar of axial type symmetry $(d_{x2-y2})$ with considerable covalent bond character. However, complex (12) shows a spectrum of octahedral geometry with $d_{z2}$ ground state. Complex (12) shows exploitation in reducing the amount of electron adducts formed in DNA during irradiation with low radiation products.

• 대한화학회지
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• 제55권6호
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• pp.912-918
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• 2011

Tetraaza Schiff base macrocyclic ligands, $L^1$,$L^2$ and their transition metal chelates have been synthesized and characterized by elemental analyses, IR, electronic, EPR and $^1H$ NMR spectra, TGA and magnetic measurements. The molar conductance of one milli-molar solution of the complexes measured in DMF indicates that the divalent metal complexes are nonelectrolyte while those of trivalent metal ion, are 1:1 electrolytic in the same solvent. The reduction of Racah parameter from the free ion value confirms the presence of considerable covalence of metal ligand sigma bond in the Co(II) and Mn(II) complexes. The EPR spectra of Cu(II) complexes at room temperature shows axial symmetry indicating a $d_x{^2}_{-y}{^2}$ ground state with significant covalent character. The thermal analysis suggests that the complexes do not contain water molecules because only the metal is left as residue.

• Bulletin of the Korean Chemical Society
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• 제17권9호
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• pp.854-857
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• 1996

Absorption and luminescence spectra of Eu3+ (aquo) and the two different 1: 3 Eu3+: ligand systems in aqueous solutions are measured under mild acidic pH condition. The oxydiacetate (ODA) and dipicolinate (DPA) ligands, forming the similar geometric complexes, are used in this work. The three intensity parameters, Ωλ (λ=2, 4, and 6) are empirically determined by applying the Judd-Ofelt theorem to the oscillator strengths of the six absorption bands arising from the ground 7F0 state. Among the three intensity parameters, the Ω2 is found to response markedly to a miner change in the ligand environment via the 7F0→5D0 transition. In addition, the relative oscillator strengths of the four luminescence bands in the visible region, assigned to the 5D0→7FJ (J=1, 2, 3 and 4) transitions are obtained to investigate their sensitivity to the ligand environment. Among the four bands, the 610 nm band, attributed to the 5D0→7F2 transition, shows hypersensitivity in the luminescence.

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.434-437
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• 1989

The pH dependence of the absorption and fluorescence of 4-hydroxy-2-methyl-1,2-benzothiazinenecarboxylat es, piroxicam and HMBDC have been measured and compared with the solvent dependence of the spectra reported previously. Four different prototropic species are observed in both ground and excited states of piroxicam ; the cation, the neutral, the anion and the dianion, while three different species such as the cation, the neutral and the anion are observed in HMBDC. The $pK_a$ and $pK_a^{\ast}$ have been determined by absorptiometric titration and Forster cycle method, respectively. The probable structure of each species has been proposed on the basis of the intramolecular phototautomerism.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.68.2-68.2
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• 2010

Dye-sensitized solar cells (DSSC) show great promise as an inexpensive alternative to conventional p-n junction solar cells. Investigations into the various factors influencing the photovoltaic efficiency have recently been intensified. The conventional absorber electrode in DSSC is composed of compacted or sintered $TiO_2$ nanopowder that carries an anchored organic dye. The absorbance of incident light in the DSC is realized by specifically engineered dye molecules placed on the semiconductor electrode surface ($TiO_2$). The dye absorbs light at wavelengths up to about 920nm, the energy of the exited state of the molecule should be about 1.35eV above the electronic ground state corresponding to the ideal band gap of a single band gap solar cell. The dye molecules ar adhered onto the nanostrutured $TiO_2$ electrode by immersing the sintered electrode into a dye solution, typically 3mM in alcohol, for a long enough period to fully impregnate the electrode. However, the concentrations of the dye is slightly changed due to the evaporation of the alcohol. The dye is more expensive than other materials in DSSC and related to the efficiency of DSSC. Therefore, the concentrations of the dye should be carefully measured. In this study, we investigated to the dye loading on fired $TiO_2$ powder as a function of temperature by the TG-DTA and the dye solution by UV-visible spectroscopy after the impregnation process. The dye loading is related to the porosity of the nanostructured $TiO_2$ electrode.