• Journal of The Geomorphological Association of Korea
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• v.19 no.2
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• pp.99-111
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• 2012

The purpose of this study is to identify the change of geographical (or geomorphological) location environment of the dwelling site and its cause in Daejon Basin during transition from the Bronze Age to the Proto Three Kingdoms Period. In order to achieve this goal, it was divided into (1) 'comparison of the total number of dwelling sites of a group of remains (or high-density dwelling remains)' and (2) 'comparison of the total number of dwelling sites in certain remains including locations of dwelling of two periods' and location environment was compared to each other in aspects of altitude, gradient, 'distance from the river of water available for use' and 'the difference between the highest altitude and lowest altitude of river bed of water available for use' based on change of period. The results were as follows: 1. looking at a change of individual factors, the altitude was elevated and the gradient was increased. The distance from the river of water available for use was decreased or increased in case of 'small scale river' and it was very little difference or increased in case of 'medium scale river'. The difference between the highest altitude and lowest altitude of river bed of water available for use was increased in case of 'small scale river' and it was increased or decreased in case of 'medium scale river'. If comparing the individual factors to each other, the increase and decrease of altitude, gradient and the difference between the highest altitude and lowest altitude of river bed of water available for use have the similar pattern. Especially, it was shown that the increase of gradient affected the increase of altitude and the difference between the highest altitude and lowest altitude of river bed of water available for use. In addition, it was shown that the increase and decrease of distance from the river of water available for use had the different pattern from those of altitude, gradient and 'the difference between the highest altitude and lowest altitude of river bed of water available for use'. 3. With above results, it was thought that combination of micro landform characteristics (eg. Characteristics of gradient) of low hills distributed within Daejeon Basin and rich aquatic environment surrounding the low hills affected the selection of location of dwelling sites at the time. Especially, it was shown that 'gradient and distance from the river of water available for use' were relatively more important factors for the inhabitants at the time to select the location of dwelling sites compared to 'altitude and difference between the highest altitude and lowest altitude of river bed of water available for use' upon selecting the location of dwelling.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.427-446
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• 2008

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

• Journal of Family Resource Management and Policy Review
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• v.25 no.3
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• pp.87-102
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• 2021

Child abuse and neglect are recently increasing in Korea, and although the government has actively improved the child protection system, the number of abused children and the rate of cases judged as abuse have continuously risen. Given that 75% of child abusers are parents, child abuse and neglect are expected to recur. To prevent such a recurrence, various intervention programs for abused children and their parents are required. The purpose of this study were to design a recovery support service process and investigate the effectiveness of pilot program for families of origin, including neglected(protected) children, to improve the system by which these programs are operated, and formulate policy alternatives that reinforce "family preservation" principles. The pilot program was implemented from June to November 2020 in 4-local healthy family support center. The number of program participants and the frequency of participation in each other differed, because of the difference in number of confirmed coronavirus cases in each region and the requirement for social distancing. Through the program, a community-based service process was developed for neglected(protected) children and their parents, and cooperative networks between related facilities and institutions were established. The study formulated the following recommendations: First, a cooperation system among government departments mandated to provide different services to neglected(protected) children is needed. Second, wider and various channels through which abused children can avail of protective services should be developed within communities. Third, more stable environments for program operation should be cultivated, and cooperative partnerships should be sought for knowledge sharing among relevant government departments. Another necessary measure is for a center to develop its own business model, in which the duplication of services provided by involved organizations is avoided. Finally, clear guidelines, administrative standards, and specific plans for program operation should be arranged. Also regional characteristics are maintained, but services should be standardized.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.63-70
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• 2021

As the government strengthens its policy of separating and discharging packaging materials, consumers are increasingly dissatisfied. In order to increase consumer participation in separate discharge policy of packaging materials, it is necessary to increase the willingness to participate by reducing potential consumer problems such as removal of packaging labels. This study conducted a survey of 300 consumers aged 14 and over who recycle and discharge directly from their homes. Ninety-nine percent of consumers said PET bottles are released separately. However, only 65% of consumers removed labels (attachment labels, shrink labels) and other materials (caps, vinyl coatings, tapes, handles, bases, etc.) during separate discharge process. Nearly 52% of consumers cited 'difficulty of separation' as the main reason for not removing labels and other materials. One-way ANOVA analysis showed that 'strong adhesion', 'removal initiation problem' and 'material strength' had high mean regardless of age, which are major factors impedes label removal. Using shrink labels with perforated lines rather than adhesive labels would be more beneficial to encouraging participation in separate discharge. However, if the shrink labels do not have perforated lines or are difficult to remove, adhesive labels are often easier to remove than shrink labels because of the strong cohesiveness of shrink labels. As a result, how easy it is for consumers to remove the label is more important than technological differences. In order to increase consumer participation in packaging material and label separations, improvements in structural design are needed along with the selection of materials that are easy to separate. This study is meaningful in examining consumer perceptions, deriving problems and suggesting directions for policy improvement.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.33-38
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• 2021

Recently, rollable and foldable displays are attracting great attention in the flexible display market due to their excellent form factor. To predict and prevent the mechanical failure of the display panels, it is essential to accurately understand the mechanical properties of brittle SiN_x thin films, which have been used as an insulating film in flexible displays. In this study, tensile properties of the ~130 nm- and ~320 nm-thick SiN_x thin films were successfully measured by coating a ~190 nm-thick organic nano-support-layer (PMMA, PS, P3HT) on the fragile SiN_x thin films and stretching the films as a bilayer state. Young's modulus values of the ~130 nm and ~320 nm SiN_x thin films fabricated through the controlled chamber pressure and deposition power (A: 1250 mTorr, 450 W/B: 1000 mTorr, 600 W/C: 750 mTorr, 700 W) were calculated as A: 76.6±3.5, B: 85.8±4.6, C: 117.4±6.5 GPa and A: 100.1±12.9, B: 117.9±9.7, C: 159.6 GPa, respectively. As a result, Young's modulus of ~320 nm SiN_x thin films fabricated through the same deposition condition increased compared to the ~130 nm SiN_x thin films. The tensile testing method using the organic nano-support-layer was effective in the precise measurement of the mechanical properties of the brittle thin films. The method developed in this study can contribute to the robust design of the rollable and foldable displays by enabling quantitative measurement of mechanical properties of fragile thin films for flexible displays.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.525-547
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• 2021

The main purpose of this study is to examine the use of plant species in ecological restoration projects. To this end, planting drawings from 58 sites that had completed the return of the ecosystem conservation cooperation fund for the past six years were collected and analyzed. The analysis used the construction completion and design drawings to determine the overall selection status and analyze frequency by classifying planted plants into wild and cultivated plants by nature, size, vegetation climate, and upland and wetland habitat. The investigation and analysis process found many cases of wrong plant names, so an analysis was also performed on the matter. In the 58 investigation sites, 282 plants were used for planting: 91 tree species, 69 shrub species, 11 vine species, and 111 herbal species. The most commonly used plant species was Spiraea prunifolia f. simpliciflora, followed by Sorbus alnifolia, Quercus acutissima, Zoysia japonica, Callicarpa dichotoma, and Weigela subsessilisin that order. The most commonly used tree species was Sorbus alnifolia,followed by Quercus acutissima, Zelkova serrata, Chionanthus retusus, and Cornus officinalis, in that order. The most commonly used shrub species was Spiraea prunifolia f. simpliciflora, followed by Weigela subsessilis, Callicarpa dichotoma, Rhododendron yedoense f. poukhanense. and Euonymus alatusin that order. The most commonly used herbal plant species was Zoysia japonica, followed by Dendranthema zawadskii var. latilobum, Aster koraiensis, Miscanthus sacchariflorus, and Pennisetum alopecuroidesin that order. In the analysis by vegetation climate, Spiraea prunifolia f. simpliciflora, Callicarpa dichotoma, and Sorbus alnifoliawere most used in that order in both the temperate central and the warm temperate forest zones, but the pattern does not properly reflect the climate characteristics. In the analysis by habitat, Miscanthus sacchariflorus and Lythrum salicariawere most used in the wetland. In particular, the ratio of wild plants to cultivated plants was 76% to 24%, indicating the ratio of selecting cultivated plants was high. The names of plants on the drawings were mostly common names that did not appear in the Korea National Arboretum or the National Species List of Korea. It is necessary to use proper plant names in the future. Regarding the use of planting plants for ecological restoration, it is necessary to adopt the approach of diversifying selected plants, selecting plants according to characteristics of climate zones, and lowering the specifications of plants used for ecological restoration. Moreover, it is important to fully understand the ecological characteristics of wetland plants and minimize the ratio of using cultivated plants to ensure the plant selection centered on wild plants.

• Clean Technology
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• v.27 no.4
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• pp.332-340
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• 2021

With the recent reinforcement of emission standards, it is necessary to make efforts to reduce NOx from air pollutant-emitting workplaces. The NOx reduction method mainly used in industrial facilities is selective catalytic reduction (SCR), and the most commercial SCR catalyst is the ceramic honeycomb catalyst. This study was carried out to reduce the NOx emitted from steel plants by applying De-NOx catalyst coated on metallic monolith. The De-NOx catalyst was synthesized through the optimized coating technique, and the coated catalyst was uniformly and strongly adhered onto the surface of the metallic monolith according to the air jet erosion and bending test. Due to the good thermal conductivity of metallic monolith, the De-NOx catalyst coated on metallic monolith showed good De-NOx efficiency at low temperatures (200 ~ 250 ℃). In addition, the optimal amount of catalyst coating on the metallic monolith surface was confirmed for the design of an economical catalyst. Based on these results, the De-NOx catalyst of commercial grade size was tested in a semi-pilot De-NOx performance facility under a simulated gas similar to the exhaust gas emitted from a steel plant. Even at a low temperature (200 ℃), it showed excellent performance satisfying the emission standard (less than 60 ppm). Therefore, the De-NOx catalyst coated metallic monolith has good physical and chemical properties and showed a good De-NOx efficiency even with the minimum amount of catalyst. Additionally, it was possible to compact and downsize the SCR reactor through the application of a high-density cell. Therefore, we suggest that the proposed De-NOx catalyst coated metallic monolith may be a good alternative De-NOx catalyst for industrial uses such as steel plants, thermal power plants, incineration plants ships, and construction machinery.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.160-168
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• 2018

Study Design: Retrospective study of prospectively-collected data. Objectives: To determine the factors associated with conversion from conservative to surgical treatment in single-level lumbar spinal stenosis patients. Summary of Literature Review: Various reports have presented clinical outcomes after the surgical and nonsurgical treatment of spinal stenosis. However, few reports have investigated factors predicting conversion to surgery during the course of conservative treatment. Materials and Methods: We analyzed 40 patients who visited our hospital from May 2010 to May 2015 and were traceable for at least 3 years after being advised to undergo surgery following 3 months of conservative treatment. Of these patients, 20 underwent surgery and 20 did not. We then investigated the factors associated with conversion to surgical treatment. Clinical assessments were conducted using a questionnaire, and the overall area of the spinal canal and the muscle area within the spinal canal were measured using magnetic resonance imaging. Results: The average area of the spinal canal was $81.40{\pm}53.61mm^2$ in the surgical group, compared to $127.75{\pm}82.55mm^2$ in the nonsurgical group (p=0.042). The muscle area in the spinal canal was $5.17{\pm}1.30cm^2$ in the surgical group, whereas it was $6.40{\pm}1.56cm^2$ in the nonsurgical group (p=0.010). The patients in the surgical group were more likely to have experienced repetitive strain and to have frequently visited health clubs (p=0.047, p=0.037, respectively). However, regular stretching was more common in the nonsurgical group (p=0.028). Conclusions: The factors associated with conversion to surgical treatment were a narrow spinal canal, a small muscle area within the spinal canal, visiting health clubs, repetitive sprain, and not stretching. A small muscle area within the spinal canal can be considered as a key factor related to surgical conversion.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.147-153
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• 2018

Study Design: Retrospective case series. Objectives: We retrospectively evaluated the clinical efficacy of postganglionic nerve block in symptomatic Schmorl nodules (SNs). Summary of Literature Review: SNs are common lesions that are often asymptomatic. In certain cases, SNs have been reported to cause severe axial back pain, thereby considerably impacting patients' quality of life. No consensus currently exists on the treatment of symptomatic SNs. Materials and Methods: From October 2015 to October 2017, a total of 21 patients with symptomatic SNs diagnosed by magnetic resonance imaging (MRI) that did not respond to conservative treatment after 4 weeks were included in the study. All patients received postganglionic nerve block. We evaluated effective pain relief (improvement of back pain of more than 50% compared with before the intervention) and functional improvements, assessed by visual analogue scale (VAS) and Oswestry Disability Index scores obtained at 4 hours, 4 weeks, 8 weeks, 3 months, and 6 months after the procedure. Results: Symptomatic SNs were more common at the L2-3 level, and the lower end plate was more commonly involved than the upper end plate. Eighteen of the 21 patients (85.7%) showed effective pain relief, and no deterioration was observed within the followup period. Throughout the follow-up period, the VAS remained significantly improved compared to before the procedure (p<0.05). Complications were not reported in any cases. Conclusions: Postganglionic nerve block for symptomatic SNs that do not respond to conservative treatment is a non-invasive modality for pain relief.

• Journal of Korean Society of Spine Surgery
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• v.25 no.4
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• pp.154-159
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• 2018

Study Design: Retrospective radiographic study. Objective: To evaluate the characteristics of concurrent degenerative cervical and lumbar spondylolisthesis. Summary of Literature Review: Concurrent degenerative cervical and lumbar spondylotic diseases have been reported. Given that severe spondylosis can result in spondylolisthesis, one might expect that concurrent spondylolisthesis of the cervical and lumbar spines might also be prevalent. However, the incidence of spondylolistheses in the lumbar and cervical spines might differ due to anatomical differences between the 2 areas. Nonetheless, there is minimal information in the literature concerning the incidence of concurrent cervical and lumbar spondylolisthesis. Material and Methods: We evaluated standing cervical and lumbar lateral radiographs of 2510 patients with spondylosis. Concurrence, age group, gender, and direction of spondylolisthesis were evaluated. Lumbar spondylolisthesis was defined as at least Meyerding grade I and degenerative cervical spondylolisthesis was defined as over 2 mm of displacement on standing lateral radiographs. Results: Lumbar spondylolisthesis was found in 125 patients (5.0%) and cervical spondylolisthesis was found in 193 patients (7.7%). Seventeen patients had both degenerative cervical and lumbar spondylolistheses (0.7%). Lumbar spondylolisthesis is a risk factor for coexisting cervical spondylolisthesis. Lumbar spondylolisthesis was more common in females than males, independent of advancing age. In contrast, degenerative cervical spondylolisthesis was more common in older patients, independent of gender. Anterolisthesis was more common in the lumbar spine. Retrolisthesis was more common in the cervical spine. Conclusions: There was a higher prevalence of degenerative cervical spondylolisthesis in patients with degenerative lumbar spondylolisthesis.