• Journal of Technology Innovation
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• v.25 no.1
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• pp.61-89
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• 2017

This study aims to estimate empirically the respective impacts of R&D expenditure, R&D labor, overseas direct investment, commodity trade balance, and technology trade openness on technology balance of payments. To examine the presence of co-integration between them, this paper employed the ARDL-bounds test using time series data from 1981 to 2014, and the result shows that there is a stable long-run equilibrium relationship among them. Furthermore, we estimated long- and short-run coefficients of the technology balance of payments with respect to each variables based on long-run equilibrium equation and error correction model. As a result, the technology balance of payments respond negatively to R&D labor and technology trade openness, and R&D expenditure does produce positive effects in the long-run, while coefficients of overseas direct investment and commodity trade balance in the long-run are not statistically significant. Besides, according to results of error correction model, overseas direct investment only has clearly a positive effects in the short-run, in contrast, the short-term relationships between the other variables and the technology balance of payments could not definitively derived. This implies that it is necessary to procure and cultivate talented personnel, as well as to enlarge gradually technology trade size in order to improve technology balance of payments from a long-term point of view.

• Journal of the Korean Chemical Society
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• v.54 no.3
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• pp.269-274
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• 2010

The solubility and the physicochemical property (refractive index) in the NaCl-$CaCl_2$-$H_2O$ and KCl-$CaCl_2$-$H_2O$ systems were determined at $50^{\circ}C$ and the phase diagrams and the diagrams of physicochemical property vs composition were plotted. One invariant point, two univariant curves, and two crystallization zones, corresponding to sodium Chloride (or potassium chloride), dihydrate ($CaCl_2{\cdot}2H_2O$) showed up in the phase diagrams of the ternary systems. The mixing parameters ${\theta}_{M,Ca}$ and ${\Psi}_{M,Ca,Cl}$ (M = Na or K) and equilibrium constant $K_{sp}$ were evaluated in NaCl-$CaCl_2-H_2O$ and KCl-$CaCl_2-H_2O$ systems by least-squares optimization procedure, in which the single-salt Pitzer parameters of NaCl, KCl and $CaCl_2$ ${\beta}^{(0)}$, ${\beta}^{(1)}$, ${\beta}^{(2)}$ and $C^{\Phi}$ were directly calculated from the literature. The results obtained were in good agreement with the experimental data.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.871-875
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• 1999

We calculated the characteristics of a phosphoric cation exchanger and studied on an accurately computable method to determine the ion exchange capacity for type of potentiometric titration curve. The ion exchanger was prepared by phosphorylation of a styrene-divinylbenzene copolymer with 4% crosslinking. The ion exchange capacity is 5.7 meq/g. The experimental pK values versus ${\mathit{x}}$ in phosphoric cation exchanger can be expressed as a linear equation. The ${\Delta}pK$ values were obtained from the slope of linear equation. The ${\Delta}pK$ values are the differences of antilogarithms(pK) values of the apparent equilibrium constant at complete and zeroth neutralization of the ion exchanger. Also the experimental pK values at ${\mathit{x}}=0.5$ were accorded well with theoretical data. And when it is titrated with NaOH and $Ba(OH)_2$ solutions, a good agreement between experimental and theoretical pK values for various ${\mathit{x}}$ was seen in all the potentiometric titration curves. We knew that the inflection point of potentiometric titration curve in the case of divalent ions are changed much large than that for monovalent ions. If the relation between g values and ${\partial}pH/{\partial}g$ was plotted to the Lorentz distribution curve, ion exchange capacity can be accurately evaluated.

• The Korean Journal of Air & Space Law and Policy
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• v.23 no.2
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• pp.93-114
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• 2008

The purpose of this study is to review the changes in the aviation safety management system, how that system has evolved and what forces caused these changes to take place. Also included is an examination of the development process of the aviation safety management system in view of the new institutionalism, identifying the patterns of change. Based on the results of this study, I propose policy methods to design a desirable civil aviation safety system with a view toward raising the safety standards in the Korean civil aviation community. The major analysis variables are as follows: first, aviation accidents caused by external factors and international standards as independent variables second, environmental changes and political processes affecting aviation safety management system as major mediating variables and third, the aviation safety management legal system, the aviation safety management organizations and an expert participation system as dependent variables. The institutional changes and continuance of the aviation safety management system show that when specific circumstances arise, the continuance lasts depending on the path dependency, and in a certain circumstance, when immanent changing factors reach a critical point, the system suddenly changes by a punctuated equilibrium, which are all included in this study.

• Journal of the Korean Chemical Society
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• v.40 no.4
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• pp.219-228
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• 1996

An ab initio molecular orbital method has been applied to investigation of molecular properties and equilibrium geometries for hexahydroxybenzene triscarbonate (C9O9) and its analogous cyclic compounds (C9S9, C9O6S3, C9O3S6). In these works, the optimized geometry of each compound has been obtained at HF and MP2 levels. These results have shown that the optimized geometries of these compounds prefer D3h planar structure to C3v bowl structure. Calculations of harmonic vibrational frequencies have been also carried out at HF/3-21G* level to analyze normal modes of these compounds. Bonding characters of these compounds are studied by Mulliken and natural populations obtained at HF/6-31G* level. We have also studied the structures and the populations of C6O6 and C6S6 at HF and MP2 levels which are obtained by pyrolyses of C9O9 and analogous compounds. In addition, the single point calculations have been performed to predict the approximate energy barrier for pyrolysis of each compound.

• Journal of the Korean Institute of Gas
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• v.24 no.1
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• pp.17-22
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• 2020

Light Naphtha is distillated from crude oil unit and separated into the methane, ethylene and propylene by boiling point difference in sequence. This separation is conducted using a series of binary-like columns. This separation method is known that the energy consumed in the reboiler is used to separate the heaviest components and most of this energy is discarded as vapor condensation in the overhead cooler. In this study, the first two columns of the separation process are replaced with the Petlyuk column. A structural design was exercised by the stage computation with ideal tray efficiency in equilibrium condition. Compared with the performance of a conventional system of 3-column model, The design outcome shows that the procedure is simple and efficient because the composition of the liquid component in the column tray was designed to be similar to the equilibrium distillation curve. The performance of the new process indicates that an energy saving of 12.1% is obtained and the cost savings of 44 million won per day based on gross domestic product is reduced under same total number of trays and the initial investment cost is saved.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.475-490
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• 2010

The analysis of slope stability was performed from seven sites among total eleven sites of waste rock which are divided into two objects (mullock-pile and rock mass) according to the location of dumping-dropping point in L limestone Mine. The analysis of circular failure using Bishop's simplified method and the finite element method for mullock-pile slopes were adopted. For rock mass slopes, identification of failure modes on stereonet projection was determined, thereby limit equilibrium analysis was applied to obtain the safety factor of slopes and the finite element method was used to understand overall behavior of slope. Phi-c reduction method was used to calculate the safety factor of slopes through the finite element method. In mullock-pile slope of zone D and rock slopes of zone F and G, the assurance of slope stability was difficult, and the plans to assure the stability of slopes were proposed on the basis of the analysis of slopes at disposal sites of waste rock. Therefore, the method of piling with waste rock by dozer pushing after dumping for mullock-pile slope of zone D is required, and the method of piling after moving to the place which has no fault zone for rock slope of zone F and G is recommended.

• Bulletin of the Korean Chemical Society
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• v.7 no.5
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• pp.367-371
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• 1986

Dynamic and equilibrium properties of n-alkane chains immersed in solvent molecules have been investigated by a molecular dynamics method. The n-alkane chain is assumed to be a chain of elements (CH$_2$) interconnected by bonds having a fixed bond length and bond angle, but each bond of the chain is allowed to execute hindered internal rotation. We studied the effect of the number of the chain elements (N$_c$ = 10, 15 and 20) on the equilibrium properties of the system, e.g., the pair correlation functions between a chain element and solvent molecules, g$_{cs}$(r), and between the chain elements, g$_{cc}$(r), and the configurational properties such as the mean-square end-to-end distance < R$^2$ >, the mean-square radius of gyration < S$^2$ >, and the eigenvalues of the moment-of-inertia tensor < S$_i^2$ > / < S$^2$ > (i = 1, 2 and 3). We also studied the dynamic properties of the system, e.g., the autocorrelation function C(A;t) where A = R$^2$(t), = S$^2$(t), or = ${\vec{V}}(t)({\vec{V}}$ = velocity of the center of mass), and the diffusion coefficient D. The g$_{cs}$(r)'s are almost equal irrespective of the change of Nc while g$_{cc}$(r) becomes larger as N$_c$ increases; The MD computed configurational properties < R$^2$2 > and < S$^2$ > were found to be a little different from the values calculated from the statistical equations of < R$^2$ > and < S$^2$ >, it may be due to the fact that our model for the MD simulations includes a long-range volume effect. From the < S$_i^2$ > / < S$^2$ >, it is found that the chain molecule has a nearly spherical shape irrespective of the variation of N$_c$. For the dynamic properties we found that the C(R$^2$;t) and C(S$^2$;t) of lower N$_c$ decay faster than those of higher N$_c$, while the C($\vec V$;t) of the center of mass in the chain is weakly dependent on the N$_c$. The center of mass diffusion coefficient D$_c$ decreases as N$_c$ increases while the end point diffusion coefficient D$_e$ is nearly equal irrespective of the change of N$_c$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4B
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• pp.357-363
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• 2009

When yields the mean velocity of the closed conduit which is used generally, it is available to use Darcy Weisbach Friction Loss Head equation. But, it is inconvenient very because Friction Loss coefficient f is the function of Reynolds Number and Relative roughness (${\varepsilon}$/d). So, it is demanded more convenient equation to estimate. In order to prove the reliability and an accuracy of Chiu's velocity equation from the research which sees hereupon, proved agreement very well about measured velocity measurement data by using Laser velocimeter which is a non-insertion velocity measuring equipment from the closed conduit (Laser Doppler Velocimeter: LDV) and an insertion velocity measuring equipment and the Pitot tube which is a supersonic flow meter (Transit-Time Flowmeters). By proving theoretical linear-relation between maximum velocity and mean velocity in laboratory flume without increase and decrease of discharge, the equilibrium state of velocity in the closed conduit which reachs to equilibrium state corresponding to entropy parameter M value has a trend maintaining consistently this state. If entropy M value which is representing one section is determinated, mean velocity can be gotten only by measuring the velocity in the point appearing the maximum velocity. So, it has been proved to estimate simply discharge and it indicates that this method can be a theoretical way, which is the most important in the future, when designing, managing and operating the closed conduit.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.397-410
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• 2000

Skeletal class III had been classified by the position of the maxilla, the mandible, the maxillary alveolus, the mandibular alveolus and vertical development. This morphologic approach is simple and useful for clinical use, but it is insufficient to permit understanding of the pathophysiology of dysmorphoses. The author hypothesizes that there are different patterns of mutual relation of the skeletal components which have contributed pathologic equilibrium of skeletal class III. The purpose of this study are threefold: 1) to classify skeletal class III in subgroups, which can show the architectural characteristics of the deformity, 2) to analyse the craniofacial architecture of each subgroup on etio-pathogenic basis, and 3) to characterize and visualize the pattern as a prototype. Materials used in this study were lateral cephalograms of 106 skeletal class III adults, which were analysed with modified Delaire's architectural and structural analysis. Linear and angular measurements of the individual subject were obtained and cluster analysis was used for the subgrouping. Data were evaluated for verification of the statistical significances. The following results were obtained. 1. By the modified Delaire's architectural and structural analysis and cluster analysis, skeletal class III adults were classified into 7 clusters and presented as prototypes, which could show the pathophysiology of the skeletal architecture 2. There was significant relationship in measurement variables of each cluster, which could reflect characteristics of the skeletal pattern of growth. 3. The flexure of cranial base had a close relationship to the anterior rotational growth of the maxilla and contributes to understand the etio-pathology of skeletal class III. 4. The proportion of craniospinal area in cranial depth, craniocervical angle and vertical position of point Om had a close relationship to rotational growth of the mandible and direction of condylar growth. They contribute to understand the etio-pathology of skeletal class III. In summary, the cranium and the craniocervical area must be considered in diagnosis and treatment planning of dentofacial deformity. And the occlusal plane can be considered as a representative which shows the mutual relationships of the skeletal components.