• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1143-1148
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• 2010

We investigated the separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp) and phenyl ether (Pe) by liquid membrane permeation (LMP). A batch-stirred tank was used as the permeation unit. An aqueous solution of saponin and n-hexane were used as the liquid membrane and the outer oil phase, respectively. Yield and selectivity of individual NHC was much larger than that of BAC, Bp and Pe. Increasing the initial mass fraction of the saponin to the membrane solution ($C_{sap,0}$) and the initial volume fraction of O/W emulsion to total liquid in a stirred tank (${\phi}_{OW,0}$) resulted in deteriorating the yield of individual NHC, but increasing the stirring speed (N) resulted in improving the yield of each NHC. With increasing $C_{sap,0}$, the selectivity of each NHC based on DMNs increased. Increasing ${\phi}_{OW,0}$ and N resulted in decreasing the selectivity of individual NHC based on DMNs. At an experimental condition fixed, the sequence of the yield and selectivity in reference to DMNs for each NHC was Q > Qu = iQ > In. Furthermore, we compared LPM method with methanol extraction method in view of the separation efficiency (yield, selectivity) of NHC.

• Journal of Korean Elementary Science Education
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• v.17 no.2
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• pp.79-90
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• 1998

The purpose of this study is to investigate degree of the concept formation on cell in elementary school teachers and to clarify the patterns of their misconceptions. Data were collected by interview with 120 elementary school teachers, ranged from twenties to fifties in age, working in Taegu city. The instrument was developed by researchers and was categorized into four: cell as the basic units of life, morphology of cell, function of cell, growth of individual from the viewpoint of cell. The results are as follows: First, about 80% of teachers had two perspective outcome of cell: Cells are the basic units of life on earth. But the potato and meat, which we used to eat as food, are not constructed of cells but aggregated of nutrients. Second, most of elementary school teachers recognized that shapes of the cell in organisms were diverse, but some of them only could present several kinds of shape on cell. The 35% of teachers had misconception that shape of cell is all the same in a individual. It shows that this result is caused by lack of opportunity to observe the various kinds of cells. Third, most teachers understood tell can be seen only through a microscope. Yet in comparison with relative size, it was revealed that misconception of cell size was induced by the term of 'basic unit'. In addition, they thought that large organisms are built from large cells, and small organisms from small cells. Fourth, Elementary school teachers used to confuse the terms between chloroplast and chlorophyll, and believed that the genetic material was contained only in the reproductive cells and seeds. It was also revealed that they thought the nutrients such as starch and fat are located at intercellular space. Fifth, the 60% of teachers conceived correctly that growth of individual depends on mitosis and increase in cell number. The rest of them, however, misunderstood that it is due to the increase of tell volume.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.412-424
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• 2004

Statement of problem: Several prosthetic options are available for the restoration of multiple adjacent implants. A passively fitting prosthesis has been considered a prerequisite for the success and maintenance of osseointegration. Passivity is a particular concern with multiple implants because of documented inaccuracies in the casting and soldering process. One way to avoid this problem is to restore the implants individually, however, the restorations of individual adjacent impants requires careful adjustment of interproximal contacts. Purpose: The purpose of this study was to compare the stress distribution pattern and amount surrounding Bicon implants with individual crowns and splinted restorations. Material and method: A photoelastic model of a human partially edentulous left mandible with 3 Bicon implants($4{\times}11mm$) was fabricated. For non-splinted restorations, individual crowns were fabricated on 3 abutments ($4{\times}0.65mm,\;0^{\circ}$, 2.0 mm post, Bicon Inc., Boston, USA) After the units were cemented, 4 levels of interproximal contact tightness were evaluated: open, ideal ($8{\mu}m$ shim stock drags without tearing), medium($40{\mu}m)$), and heavy($80{\mu}m$). Splinted 3-unit fixed partial dentures were fabricated and cemented to the model. Changes in stress distribution under simulated non-loaded and loaded conditions(7.5, 15, 30 lb) were analyzed with a circular polaricope. Results: 1. Stresses were distributed around the entire body of fin in Bicon implants. 2. Splinted restorations were useful for distribution of stress around implants especially with higher loads. 3. By increasing the contact tightness between the individually restored three implants, the stress increased in the coronal portion of implants. Conclusions: Ideal adjustment of the contact tightness was important to reduce the stresses around individually restored Bicon implants.

• Korean Journal of Veterinary Research
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• v.47 no.4
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• pp.417-423
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• 2007

Serological surveillance programs in animal populations are becoming increasingly important to estimate prevalence of a specific disease and subsequently to document disease-free status in a region or a country. For these purposes, the programs need to be based on both theoretical and economical aspects from the designing phase. From Aujeszky's disease (AD)-eradication program point of view, group of animals (aggregates, herds) not individual animal is the more important sampling unit of concern. In this study the authors therefore attempted to compute an appropriate sample size tailored to a current surveillance program against AD, assuming that the goal of this program is either herd-level prevalence estimation or documentation of AD-freedom. For prevalence estimation, assuming a finite population with imperfect sensitivity (Se) and specificity (Sp) of ELISA kit for AD diagnosis, the number of herds present, expected herd prevalence, and desired accuracy for a certain level of confidence, sample size was estimated at herd-level in the first stage and individual animal-level in the second stage. A two-stage sampling design was used to calculate a sample size to indicate AD-freedom. In this instance, the computation was based on the possible detection of a predetermined prevalence at a certain herd-level Se and Sp. This study indicated that the sample size varied with predetermined confidence, tolerance, Se and Sp at herd- and animal-level, and within- and among-herd prevalence. In general, smaller sample size was required to estimate AD prevalence than to document of AD-freedom. Compared to individual-based samples, two-stage sampling strategy requires a larger sample size to show disease-freedom. Statistical considerations including herd-level test characteristics when designing surveillance program also are further discussed.

• Korea Journal of Hospital Management
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• v.8 no.1
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• pp.135-164
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• 2003

The operating room is the major facility that costs the highest investment per unit area in a hospital. It requires commitment of hospital resources such as manpower, equipments and material. The quantity of these resources committed actually differs from one type of operation to another. Because of this, it is not an easy task to allocate the operating cost to individual clinical departments that share the operating room. A practical way to do so may be to collect and add the operating costs incurred by each clinical department and charge the net cost to the account of the corresponding clinical department. It has been customary to allocate the cost of the operating room to the account of each individual department on the basis of the ratio of the number of operations of the department or the total revenue by each operating room. In an attempt to set up more rational cost allocation method than the customary method, this study proposes a new cost allocation method that calls for itemizing the operation cost into its constituent expenses in detail and adding them up for the operating cost incurred by each individual department. For comparison of the new method with the conventional method, the operating room in the main building of hospital A near Seoul is chosen as a study object. It is selected because it is the biggest operating room in hospital A and most of operations in this hospital are conducted in this room. For this study the one-month operation record performed in January 2001 in this operating room is analyzed to allocate the per-month operation cost to six clinical departments that used this operating room; the departments of general surgery, orthopedic surgery, neuro-surgery, dental surgery, urology, and obstetrics & gynecology. In the new method(or method 1), each operation cost is categorized into three major expenses; personnel expense, material expense, and overhead expense and is allocated into the account of the clinical department that used the operating room. The method 1 shows that, among the total one-month operating cost of 814,054 thousand wons in this hospital, 163,714 thousand won is allocated to GS, 335,084 thousand won to as, 202,772 thousand won to NS, 42,265 thousand won to uno, 33,423 thousand won to OB/GY, and 36.796 thousand won to DS. The allocation of the operating cost to six departments by the new method is quite different from that by the conventional method. According to one conventional allocation method based on the ratio of the number of operations of a department to the total number of operations in the operating room(method 2 hereafter), 329,692 thousand won are allocated to GS, 262,125 thousand won to as, 87,104 thousand won to NS, 59,426 thousand won to URO, 51.285 thousand won to OB/GY, and 24,422 thousand won to DS. According to the other conventional allocation method based on the ratio of the revenue of a department(method 3 hereafter), 148,158 thousand won are allocated to GS, 272,708 thousand won to as, 268.638 thousand won to NS, 45,587 thousand won to uno, 51.285 thousand won to OB/GY, and 27.678 thousand won to DS. As can be noted from these results, the cost allocation to six departments by method 1 is strikingly different from those by method 2 and method 3. The operating cost allocated to GS by method 2 is about twice by method 1. Method 3 makes allocations of the operating cost to individual departments very similarly as method 1. However, there are still discrepancies between the two methods. In particular the cost allocations to OB/GY by the two methods have roughly 53.4% discrepancy. The conventional methods 2 and 3 fail to take into account properly the fact that the average time spent for the operation is different and dependent on the clinical department, whether or not to use expensive clinical material dictate the operating cost, and there is difference between the official operating cost and the actual operating cost. This is why the conventional methods turn out to be inappropriate as the operating cost allocation methods. In conclusion, the new method here may be laborious and cause a complexity in bookkeeping because it requires detailed bookkeeping of the operation cost by its constituent expenses and also by individual clinical department, treating each department as an independent accounting unit. But the method is worth adopting because it will allow the concerned hospital to estimate the operating cost as accurately as practicable. The cost data used in this study such as personnel expense, material cost, overhead cost may not be correct ones. Therefore, the operating cost estimated in the main text may not be the same as the actual cost. Also, the study is focused on the case of only hospital A, which is hardly claimed to represent the hospitals across the nation. In spite of these deficiencies, this study is noteworthy from the standpoint that it proposes a practical allocation method of the operating cost to each individual clinical department.

• Interaction and multiscale mechanics
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• v.5 no.3
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• pp.229-265
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• 2012

Hygroexpansion of wood is a known and undesired characteristic in civil engineering. When wood is exposed to changing environmental humidity, it adsorbs or desorbs moisture and warps. The resulting distortions or - at restrained conditions - cracks are a major concern in timber engineering. We herein present a multiscale model for prediction of the macroscopic hygroexpansion behavior of individual pieces of softwood from their microstructure, demonstrated for spruce. By applying poromicromechanics, we establish a link between the swelling pressure, driving the hygroexpansion of wood at the nanoscale, and the resulting macroscopic dimensional changes. The model comprises six homogenization steps, which are performed by means of continuum micromechanics, the unit cell method and laminate theory, all formulated in a poromechanical framework. Model predictions for elastic properties of wood as functions of the moisture content closely approach corresponding experimental data. As for the hygroexpansion behavior, the swelling pressure has to be back-calculated from macroscopic hygroexpansion data. The good reproduction of the anisotropy of wood hygroexpansion, based on only a single scalar calibration parameter, underlines the suitability of the model. The multiscale model constitutes a valuable tool for studying the effect of microstructural features on the macroscopic behavior and for assessing the hygroexpansion behavior at smaller length scales, which are inaccessible to experiments. The model predictions deliver input parameters for the analysis of timber at the structural scale, therewith enabling to optimize the use of timber and to prevent moisture-induced damage or failure.

• The Journal of Korean Association of Computer Education
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• v.6 no.3
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• pp.151-162
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• 2003

In 21 century information age, teachers have to help students' learning activities can be more self- directed learning. The web with diverse audio-visual materials and a great deal of interactions among contents shows lots of possibilities as one of the methods to provide self-directed learning environment for students. It allows learning environment for students to study more self-directed way by following individual learning styles, need, ability, etc. Although the best instructional method is personal field experience in the view of the characteristic of Practical Arts education. a web courseware can be a great substitutional method for improving learning effectiveness in relation to cost, safety, time limit for direct personal field experience. Therefore, the purpose of this study is to develop a web courseware for the unit 'Raising Animals' in Elementary school 6th grade Practical Art which is very difficult unit for teachers to provide direct experience environment for students. The researchers also applied the web courseware in 6th grade classrooms and described the results briefly. However, the researchers did not intend to conduct a full field implementation of the program to evaluate the program. That will be conducted in a following.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1207-1210
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• 2003

The effect of solvent structure on the slope in the plot of ln K vs. solute carbon number was examined. It was found that the free energy of methylene group transfer from the gas phase into a solvent was always negative and that the absolute magnitude of interaction free energy between the methylene group and the solvent was always larger than the absolute magnitude of cavity formation free energy of the methylene group in the solvent. Thus, the slope in the plot of ln K vs. solute carbon number was always positive and its value decreases with increase of solvent polarity since the cavity formation energy of the CH₂ unit increases with increase of solvent polarity while the dispersive interaction energy of the CH₂ unit is virtually invariant. We also examined the effect of sequential addition of CH₂ unit to a solvent molecule upon ln K for three homologous series of solvents: n-alkanes, n-alcohols, and n-nitriles. Characteristic trends in the plots of ln K vs. solvent carbon number were observed for individual solvent groups. A decrease of ln K with solvent carbon number was observed for n-alkanes. An abrupt increase in ln K followed by levelling off was observed for n-alcohols while a final slight decrease in ln K after an abrupt increase followed by rapid levelling off was noted for n-nitriles. All of theses phenomena were found related to variation in cavity formation energy. It was clearly shown that a structural change of a polar solvent by sequential addition of CH₂ units causes an abrupt polarity decrease initially, then gradual levelling off, and finally, conversion to a virtually nonpolar solvent if enough CH₂ units are added.

• Korean Institute of Interior Design Journal
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• v.20 no.1
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• pp.146-153
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• 2011

The purpose of this study was to analyze the type of extended-balcony floor plan which has been reflected as a various forms after making amendment to the apartment extended-balcony legislation on December 2005 and to understand the design tendency of housing unit plan and the characteristic of living space planning by the type of size(pyeong) and extension. The objects of analysis and the plans are 333 example(235 of $84m^2$, 98 of $59m^2$) from the LH corporation competition. The design tendency of balcony space after extension is as follows; First, a type of extension for simple area to increase the area of room adjacent to balcony through balcony extension. Second, a type of functional reinforcement for private room to separate the mixed function followed by strengthening the individual function of the private room. Third, a type of ${\alpha}$-room to play new functions as hobby room, study room, soho-type room with working from home by extending balcony. Fourth, a integrated type to increase flexible efficiency of bed room, living room and kitchen by integrating extended-balcony from the flexible plan. Along with the evaluation of living style through user's environment-behavior research and the counterplan for evacuation space, indoor thermal environment and space for fulfilling the original function of balcony should be proposed in the future study.

• Korean Institute of Interior Design Journal
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• v.22 no.3
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• pp.22-32
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• 2013

The quality of apartment houses has been gradually upgraded. However the changes in demographic composition of residents such as seniors, disabled persons, and etc. have not been considered in the process of planning. If apartment houses are designed on the base of the concept of universal design, their residents could live as long as they want to live in. This study evaluates the Korean standard-sized apartment housing units and the common spaces of those apartment buildings, and it's outdoor environments from the perspective of universal design. The observation and measuring was conducted with the questionnaire survey with 100 residents living in those housing units. 60 items were designed for evaluating them in relation to the principles of universal design. The results are as follows : 1) In general, the principles of universal design were relatively applied to the apartment houses. However their application needs to be broadened. 2) The number of parking lots needs to be increased and the width of individual parking lot to be increased. Also, the location of gazebo and senior center needs to be placed in easily accessible areas. 3) The shape, color, finishes of the ramp and the entrance area of the apartment building and housing unit should be made more homelike. Also, the entrance area of apartment building and housing unit needs to be made large enough for residents themselves and meeting with neighbors. 4) Among all of the rooms in a housing unit, bathroom should be improved immediately. Also, the width of doors should be at least 80cm wide and the floor should be made even.