• Journal of the Korean Chemical Society
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• v.48 no.5
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• pp.473-482
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• 2004

The homobimetallic anion, $M^+({\eta}^5-MeCp)Mn(CO)_2Mn(CO)_5^-(M^+=Na^+,\;PPN^+)$was disrupted by CH2CHCH2Cl in THF at various temperatures ($20^{\circ}C~50^{\circ}C$) under the pseudo 1st order reaction conditions where excess of allyl chloride was employed under a nitrogen atmosphere. This homobimetallic anion seems to be involved in a concerted reaction mechanism in which a four-centered transition state is proposed. After undergoing the transition state, this reaction eventually leads to (MeCp)Mn$(CO)_3$ on addition of CO and $({\eta}^1-allyl)Mn(CO)_5$, respectively. However, in case of $Na^+$ analog, $Na^+$ may play a novel counter ion effect on the disruption reaction either by transferring one terminal CO from the $Mn(CO)_5$ moiety on to the $({\eta}^5-MeCp)Mn(CO)_2$of the corresponding homobimetallic complex, eventually resulting in $({\eta}^5-MeCp)Mn(CO)_3$ or through the interaction between $Na^+$ and the leaving group (Cl) of allyl chloride. This reaction is of overall second order with respect to homobimetallic complex with the activation parameters (${\Delta}H^{\neq}=17.15{\pm}0.17kcal/mol,\;{\Delta}S^{\neq}=-9.63{\pm}0.10$ e.u. for $Na^+$ analog; ${\Delta}H^{\neq}=22.13{\pm}0.21 kcal/mol,\;{\Delta}S^{\neq}=9.74{\pm}0.19$ e.u. for $PPN^+$ analog reaction).

• Clean Technology
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• v.11 no.3
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• pp.123-128
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• 2005

Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

• KSBB Journal
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• v.14 no.3
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• pp.328-336
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• 1999

A green microalga, Chlorella vulgaris UTX 259, was cultivated in a bench-scale raceway pond. During the culture, 15%(v/v) $CO_2$ was supplied and industrial wastewater discharged from a steel-making plant was used as a culture medium. In a small scale culture bottle, the microalga grew up to 1.8 g $dm^{-3}$ of cell concentration and ammonia was completely removed from the wastewater with an yield coefficient of 25.7 g dry cell weight $g^{-1}\;NH_3-N$. During the bottle-culture, microalga was dominant over heterotrophic microorganisms in the culture medium. Therefore, the amount of carbon dioxide fixation could be estimated from the change of dry cell weight. In a semi-continuous operation of raceway pond with intermittent lighting (12 h light and 12 h dark), increase of dilution rate resulted in increase of the ammonia removal rate as well as the $CO_2$ fixation rate but the ammonia removal efficiency decreased. Ammonia was not completely removed from the medium (wastewater) of raceway pond which was operated in a batch mode under a light intensity up to 20 klux. The incomplete removal of ammonia was believed due to insufficient light supply. A mathematical model, capable of predicting experimental data, was developed in order to simulate the performance of the raceway pond under the light intensity of sun during a bright daytime. Simulation results showed that the rates of $CO_2$ fixation and ammonia removal could be enhanced by increasing light intensity. According to the simulation, 80 mg $dm^{-3}$ of ammonia in the medium could be completely removed if the light intensity was over 60 klux with a continuous lighting. Under the optimal operating condition determined by the simulation, the rates of carbon dioxide fixation and ammonia removal in the outdoor operation of raceway pond were estimated as high as $24.7 g m^{-2} day^{-1}$ and $0.52 g NH_3-N m^{-2} day^{-1}$, respectively.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.182-187
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• 2013

In closed plant production system like plant factory, changes in environmental factors should be identified for conducting efficient environmental control as well as predicting energy consumption. Since high relative humidity (RH) is essential for crop production in the plant factory, transpiration is closely related with RH and should be quantified. In this study, four varieties of lettuces (Lactuca sativa L.) were grown in a plant factory, and the leaf areas and transpiration rates of the plants according to DAT (day after transplanting) were measured. The coefficients of the simplified Penman-Monteith equation were calibrated in order to calculate the transpiration rate in the plant factory and the total amount of transpiration during cultivation period was predicted by simulation. The following model was used: $E_d=a*(1-e^{-k*LAI})*RAD_{in}+b*LAI*VPD_d$ (at daytime) and $E_n=b*LAI*VPD_n$ (at nighttime) for estimating transpiration of the lettuce in the plant factory. Leaf area and transpiration rate increased with DAT as exponential growth. Proportional relationship was obtained between leaf area and transpiration rate. Total amounts of transpiration of lettuces grown in plant factory could be obtained by the models with high $r^2$ values. The results indicated the simplified Penman-Monteith equation could be used to predict water requirements as well as heating and cooling loads required in plant factory system.

• Cartoon and Animation Studies
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• s.22
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• pp.81-97
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• 2011

The technology of 'Virtual Reality' has placed in advanced tools for human beings' joy and anger together with sorrow and pleasure in our generation. It has recently tried in a variety ways to use as an implication for treatment in the field of Cognitive Psychology. Especially, it widely approaches to human in terms of that a sense of reality in a virtual world through the five senses should reinterpret the meaning of cognition in the real world. Based on this paradigm shift, it allows for new treatment using the technology of virtual reality. A typical example is a field of Therapy in order to overcome panic disorder. It has advantages that in particular development of flexible interaction technologies in a virtual space can lead patients to experience psychological environments rather than physical one. the interaction technology provides environments in which users' five senses can be actively stimulated, it is very useful that information from the experiences in the virtual world allows people to learn through real experiences by renewing potential energies, advantages of Virtual Reality Therapy can be customized treatment by depending on symptoms in patients with panic disorder and are capable of differentiate application for the cure at each stage. It is to treat by leading patients to get accustomed to environments and situations in real world through care process with each symptom and stage. It is helpful that based on A Human-Sensibility Ergonomics, technologies like immersive virtual reality equipment, force-relative feedback and stereophonic sound, and like stimulating the sense of smell make people to induce experiences by stimulating human's five senses. There are many advantages of immersion in virtual world in that the phenomenon such as challenge, interaction, reality, illusion, and cooperation is expanded. As an application for therapy by growing such augmented reality, virtual space and sharing of data through the Internet and also inexpensive its availability have recently expanded the base. There are other benefits of Virtual Reality Therapy offering active interaction environments for cognitive experience which can provide appropriately adjusted environments for patients who are hard to overcome the real situation because of phobia. In addition to that it is safe and economical and patients' confidentiality is assured. Moreover, due to the principles of applying real-time navigation the Virtual Reality Therapy makes modification and supplementation easier and also it can reduce cybersickness because of the supply of Lenticular allowing people to see stereoscopy without eyeglasses, which makes sense of presence clearer. On top of that due to the development of interactive technologies, it is becoming close to sense of reality similar to real world by leading users to navigate by themselves and to operate objects in a virtual space. This paper will therefore examine, although it is of limited, characteristics of application of virtual reality technology based on A Human-Sensibility Ergonomics used for treatment for a disorder. this paper will analyse a range of its application and problems and it will suggest the future possibilities.

• Journal of Science Education
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• v.38 no.3
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• pp.525-542
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• 2014

This study was performed to look into the difficulty of students in understanding science stories in 6th grade science textbooks and to analyze those factors. To do this, 6th grader (N=65) were selected from J Elementary School located in Gyeonggi-do Siheung-si as study subjects. 26 science stories in 6th grade science textbooks were classified by field and context (complement of knowledge, science history of scientists, science in life, cutting-edge science technology, environment issues) in which the characteristics were investigated and analyzed. Also, a survey about the difficulty in understanding science stories(26 items) was conducted(65 students) and a semi-structured interview was conducted for students to clarify the meaning of collected data from surveys(4 students). As result of analyzing surveys on science story context in science textbooks and interviews, 4 fields of 'energy,' 'matter,' 'life,' and 'earth' were evenly mentioned. Science in life and complement of science knowledge were mentions most for context and this had relation with the characteristic of science textbooks to provide many opportunities to apply learned knowledge in actual social issues. Reactions of students on science stories were mostly positive that they help studying science, but there was also difficulty in well understanding science stories. Difficulty of understanding context, problems of context suggesting methods, difficulty of science terminology, lack of interest, and etc. were analyzed as factors. Specific causes were mentioned to be description type class, unimportant context, lack of explanation on suggested context, problem of pictures by students.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.821-834
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• 2017

The increase in the rate of industrialization due to urbanization has caused the Urban Heat Island phenomenon where the temperature of the city is higher than the surrounding area, and its intensity is increasing with climate change. Among the cities where heat island phenomenon occurs, Seoul city has different degree of urbanization, green area ratio, energy consumption, and population density in each administrative district, and as a result, the strength of heat island is also different. So It is necessary to analyze the difference of Urban Heat Island Intensity by administrative district and the cause. In this study, the UHI intensity of the administrative gu and the administrative dong were extracted from the Seoul metropolitan area and the differences among the administrative districts were examined. and linear regression analysis were conducted with The variables included in the three categories(weather condition, anthropogenic heat generation, and land use characteristics) to investigate the cause of the difference in heat UHI intensity in each administrative district. As a result of analysis, UHI Intensity was found to be different according to the characteristics of administrative gu, administrative dong, and surrounding environment. The difference in administrative dong was larger than gu unit, and the UHI Intensity of gu and the UHI Intensity distribution of dongs belonging to the gu were also different. Linear regression analysis showed that there was a difference in heat island development intensity according to the average wind speed, development degree, Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) value. Among them, the SAVI and NDBI showed a difference in value up to the dong unit and The creation of a wind route environment for the mitigation of the heat island phenomenon is necessary for the administrative dong unit level. Therefore, it is considered that projects for mitigating heat island phenomenon such as land cover improvement plan, wind route improvement plan, and green wall surface plan for development area need to consider administrative dongs belonging to the gu rather than just considering the difference of administrative gu units. The results of this study are expected to provide the directions for urban thermal environment design and policy development in the future by deriving the necessity of analysis unit and the factors to be considered for the administrative city unit to mitigate the urban heat island phenomenon.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.195-202
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• 1998

Purpose : In order to obtain basic data for treatment plan in radiosurgery, we measured small fields of 6 MV X-rays and compared the measured data with our Monte Carlo simulations for the small fields. Materials and Methods : The small fields of 1.0, 2.0 and 3.0 cm in diameter were used in this study. Percentage depth dose (PDD) and beam Profiles of those fields were measured and calculated. A small semiconductor detector, water phantoms, and a remote control system were used for the measurement Monte Carlo simulations were Performed using the EGS4 code with the input data prepared for the energy distribution of 6 MV X-rays, beam divergence, circular fields and the geometry of the water phantoms. Results : In the case of PDD values, the calculated values were lower than the measured values for all fields and depths, with the differences being 0.3 to 5.7% at the depths of 20 to 20.0 cm and 0.0 to 8.9% at the surface regions. As a result of the analysis of beam profiles for all field sizes at a depth of loom in water phantom, the measured 90% dose widths were in good agreement with the calculated values, however, the calculated Penumbra radii were 0.1 cm shorter than measured values. Conclusion : The measured PDDs and beam profiles agreement with the Monte Carlo calculations approximately. However, it is different when it comes to calculations in the area of phantom surface and penumbra because the Monte Carlo calculations were performed under the simplified geometries. Therefore, we have to study how to include the actual geometries and more precise data for the field area in Monte Carlo calculations. The Monte Carlo calculations will be used as a useful tool for the very complicated conditions in measurement and verification.

• Clean Technology
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• v.24 no.3
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• pp.198-205
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• 2018

This study investigated the influence of catalyst preparation on the activity of $Co-CeO_2$ catalyst for $N_2O$ decomposition. $Co-CeO_2$ catalysts were synthesized by co-precipitation and incipient wetness impregnation. In order to estimate the performance of the as prepared catalysts, direct catalytic $N_2O$ decomposition test was carried out under $250{\sim}375^{\circ}C$. As a result, the catalyst prepared by co-precipitation (CoCe-CP) showed an enhanced performance on $N_2O$ decomposition reaction even in the presence of $O_2$ and/or $H_2O$, whereas the impregnation catalyst (CoCe-IM) did not. In order to investigate the difference in catalytic activity, characterization such as XRD, BET, TEM, $H_2-TPR$, $O_2-TPD$, and XPS was conducted. It is confirmed that the particle size and specific surface area were changed depending on the catalyst preparation method and the synthesis process influenced the physical properties of the catalysts. In addition, the improvement in the activity of the catalyst prepared by co-precipitation is due to the enhanced reduction from $Co^{3+}$ to $Co^{2+}$ and the improved oxygen desorption rate. However, it has been confirmed that the surface electron state and binding energy, which are related to $N_2O$ decomposition, do not change depending on the preparation method.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.164-171
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• 2002

Morphological characteristics and growth pattern of 10 Polygonatum collections indigenous to Korea were examined to select the promising medicinal, edible resources and horticultural crops. Plant heights of I0 collections ranged from 15 to 102cm. Stem type was ascending or erect, and node numbers per a stem was 6.2 to 23.2. Phyllotaxis type was alternate or verticillate, and leaf shape was elliptical or linear. Leave numbers per a stem was 5.2 to 63.4, and bract types were classified into bracteate and nonbracteate. Flowers bloomed from May 7 to May 30, and flowering period was 5 to 13 days. Inflorescence types were classified into racemose, corymbose, and umbellate. Flower numbers per a stem was 1.5 to 125.2, and flower length was 13.1 to 30.2㎜. Perianth shapes were classified into tubular, constrict and urceolate. Surface colors of rhizome were pale yellow, pale brown, brown, and dark brown. As a result of this experiment, P. sibiricum, P. odoratum var. pluriflorum and P. odoratum var. thunbergii were thought to be useful as the medicinal and edible resources plants. On the other hand, P. odoratum var. pluriflorum 'Variegata', and P. odoratum var. maximowiczii, P. lasianthum. P. involucratum, P. desoulavyi, P. humile, and P. inflatum were thought to be useful as horticultural plants.