• Journal of the Korean Chemical Society
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• v.36 no.5
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• pp.644-651
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• 1992

The kinetics of the gas phase reaction of ozone(∼0.5 torr) with sulfur trioxide was investigated in the range of 6∼12 torr pressure at 69∼150${\circ}C$. The reaction rate of ozone with sulfur trioxide was faster than the reaction rate of $O_3 in the presence of CO_2 alone. No evidence for a molecular reaction of O_3 with SO_3 was found and the faster rate is probably due to impurity (HX) from the SO_3 reactant which gives rise to a chain reaction initiated by O_3 ＋ HX → OH ＋ O_2 ＋ X and also SO_3 has a larger collision diameter, which may be attributed to the O3 thermal decomposition more feasibly. The proposed experimental law [-d(O_3)/dt] = k_a(SO_3)(O_3) ＋ k_b(O_3)^{3/2} gives a rate constant ka(M-1 s-1) = (1.55 {\pm} 0.67) {\times} 105 e-{(9.27 0{\pm}0.43)kcal/RT}.$

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.291-291
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• 2009

한국원자력연구원의 파이로 실험 시설인 ACPF (ACP Facility)에는 공학규모 전해환원 반응기가 설치되어 공정 대용량화를 위한 연구가 수행되고 있다 본 연구에서는 전해환원 공정의 Scale-up을 위해 기존 반응기를 개선하여 전해환원 실험을 수행한 결과를 담고 있다. 장치의 대형화 빛 원격운전성 향상을 위해 기존의 전해환원 반응기의 상부 플랜지는 보다 간단하게 정리되었으며 염 이송에 의한 고온 조건 노출 시간을 줄임과 동시에 염 재사용을 목적으로 상부 플랜지는 이중으로 설계되었다. 따라서, 반응 종료후 전극이 설치된 상부 플랜지를 들어 올림으로서 반응기를 불활성 분위기로 유지하는 동시에 전해환원 금속전환체를 회수 할 수 있도록 반응기가 제작되었다. 또한, 새로운 반응기는 용융염 내의 강제 유동을 위해 아르곤 버블링이 가능하도록 설계 제작되었다. 새로 제작 설치된 전해환원 반응기를 사용하여 산화물 분말을 혼합하여 준비한 모의 사용후핵연료를 사용하여 전해환원 실험을 수행하였다. 그 결과, 산화물이 충진된 음극의 전영역에서 고루 96% 이상의 높은 금속전환율을 얻었으며 시간에 따라 선택된 FP들의 용융염 내 거동을 측정하였다. 실리더 형태의 음극에서 Cs, Sr 등의 원소들이 용융염으로 시간에 따라 용출되는 것을 확인하였으며 동시에 반응기 재질인 Fe 등도 일부 용융염에서 검출되었다. 아르곤 버블링에 의한 강제 유동은 전압 및 전류 거동에는 큰 영향을 미치지 못하였으나 염의 휘발량을 증가시켜 영조성올 변화시키는 것으로 측정되었다. ACPF의 전해환원 실험결과를 바탕으로 반응기를 상부 기체상과 하부 액체상으로 나누어 전산모사를 수행하였다 상부 기체상은 유입되는 아르곤 기체와 발생되는 산소기체의 흐름을 모사하는 결과를 얻었으며 온도 및 산소의 분압을 계산하였다. 하부 액체상에서는 전기장을 모사하여 전류 밀도 등을 3차원으로 모사하였다.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.518-529
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• 1996

To develope chemical heat pump using available energy sources such as solar heat and many kinds of waste thermal energy we have studied the enhancement effect of inserted fins in cylindical packed bed reactor. Two dimensionnal(radial and circumferential) partial differential eqaetions, concerning heat and masstransfer in CaO packed bad, are solved numerically to describe the characteristics of the reaction of fins inserted reactor and heat transfer. The results obtained by numerical analysis about two dimensional profiles of temperature and conversion in the reactant in the packed bed and exothermic heat amount released from the reactor are follows; -. The insertion of fins in reactor can redue the reaction completion time by half. -. The rate of thermochemical reaction depends of the temperature and concentration and it is also governed by the boundary conditions and heat transfer rate in the particle packed bed.

• Elastomers and Composites
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• v.38 no.4
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• pp.326-333
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• 2003

Even though many studies have been reported about rubber vulcanization, it is still remained difficult to find a quantitative relationship between the final states of vulcanized rubber and initial formulation or processing conditions. Dynamic differential scanning calorimetry (DSC) method is known as a comparatively easy method to research for the rubber vulcanization in both experimental and analysis. In the present research, a study on the vulcanization reaction of NR/CB composites modified by isoprene(IR) and chloroprene(CR) rubbers is carried out using dynamic DSC method. Thermograms with several different heating rates were obtained and analyzed using the Kissinger method. Analysis showed that the vulcanization reaction was progressed through the first order reaction mechanism. In addition, the reaction temperature was severely influenced by the kinds or rubber modifiers, in this case, more influenced by CR than by IR. Those effects were clearly verified in the values of activation energy. Kinds of carbon blacks, however, could hardly influence on the reaction mechanism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.251-258
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• 2017

The objective of this study was to analyze patient satisfaction and perception of nutritional counseling services quality. A patient satisfaction and perception survey was conducted for 1,095 patients from 43 tertiary hospitals and 20 general hospitals. The number of returned questionnaires was 656 (response rate: 60.0%). Data from 633 questionnaires were analyzed after the questionnaires with unanswered items were excluded. Five domains were identified from the result of the factor analysis using the maximum likelihood and oblique rotation. The five domains were named empathy, responsiveness, tangibles, reliability, and skill and specialty. Patient perception mean score of nutritional counseling was 4.54/5.00. Patient satisfaction scores were significantly higher in empathy (P<0.001), responsiveness, and skill and specialty (P<0.01) with a college or graduate school education than in patients with a middle school education. There was no statistically significant difference between satisfaction scores in tertiary hospitals and those in general hospitals, but patients in capital hospitals reported significantly higher scores than their local counterparts in empathy, responsiveness, reliability, skill and specialty (P<0.001), and tangibles (P<0.05). In responsiveness, significantly higher (P<0.01) scores were observed in patients who received nutritional counseling only once compared to patients who received counseling two times. Patients perception of nutritional counseling services was significantly correlated with their satisfaction of five domains, reliability (r=0.721), responsiveness (r=0.697), empathy (r=0.690), skill and specialty (r=0.678), and tangibles (r=0.622).

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.625-633
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• 2018

The goal of this study is to investigate the features of Korean eighth graders' achievement and its trend in Chemistry in TIMSS 2011 and TIMSS 2015, and to explore its implications for Korean science curriculum and in teaching science. With three science educators and six science teachers, we analyzed the characteristics of Korean eighth graders' achievement in Chemistry by test-curriculum matching analysis. According to the trend analysis of science topics with released items for Chemistry in TIMSS 2015, Korean students' percentage for correct answers has dropped in topics such as regularities in chemical reactions, oxidation-reduction, etc. since these topics are covered after the ninth grade in the 2009 revised curriculum. For science cognitive domains, Korean students showed weaknesses in 'applying' domain in TIMSS 2015. Based on the results, we suggested implications for improvement in middle school chemistry curriculum and how to improve science teaching and learning for students' better science competencies and real-world application of science knowledge.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.857-862
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• 2011

3 dimensional turbine exhaust gas flow was simplified to an axisymmetrical flow and calculated with detailed chemistry models. GRI 35 species-217 reaction step model and simplified 11 species 15 reaction model was applied to the secondary reaction of the turbine exhaust gas and compared. All the model captured the secondary combustion on the base region, and the temperature was 600K higher than that without turbine exhaust gas. This means the local temperature of the base can be higher in the case of real 3 dimensional flow. The simplified model show the similar results to the GRI detailed chemistry model although the former affected the engine plume structure slightly.

• Applied Microscopy
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• v.27 no.1
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• pp.57-70
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• 1997

The distribution of glutamatergic synaptic structures in the dog basilar pons was investigated at the ultrastructural level using monoclonal antibodies against fixative-modified glutamate. Electron-dense reaction product was densely localized at the perinuclear region in the neurenal somata and often observed along the microtubules located within the dendritic processes. One or more unlabelled axon terminals made asymmetric synaptic contacts with glutamate-immunoreactive dendritic profiles. In audition, reaction product was observed either within axonal processes surrounded by myelin sheath or axon terminals. Immunoreactive axon terminals made asymmetric synaptic contact either with unlabelled or labelled dendritic profiles. These observations provided an anatomic evidence of how this excitatory neural element might perform its function in a multisynaptic pathway involving glutamatergic afferents to the basilar pons, glutamate-immunoreactive pontocerebellar projection neurons, and the glutamate-positive granule cells of the cerebellar cortex.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.852-857
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• 2008

The immobilization technique is important to extend the application field of a photocatalyst. Titanium surface was changed into a $TiO_2$ thin film by the anodizing process. The anodized $TiO_2$ had photocatalytic activity, and showed sponge like shape. The photocatalytic degradation of gas phase acetaldehyde and VOCs by anodized titania has been studied in various initial concentrations, humidity and discharge potentials. The reactivity of anodized titania was increased with relative humidity, but excessive humidity led to a decrease of the reaction rate. The electric dark discharge that was combined with photocatalytic reaction enhanced the decomposition rate of the organic compounds. But excessively applied voltage caused corona discharge, which decreased the reaction rate. Optimum relative humidity was 40% and discharge potential was 5 kV under dark discharge region in photocatalytic reaction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.300-303
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• 2010

This work shows the result of numerical simulation on a reacting flow by varying atomization properties which can be obtained from a injector for a small and low power aircraft gas turbine engine. Because the atomization properties mainly affect on the performance of the engine, a lot of efficiency tests are needed when a new injector is developed. Nowadays researches has been actively performed using computational analysis. Using commercial package CFD-ACE+, basic studies on the reacting flow field have been conducted. Those results show that the reaction rate is increased when higher pressure and wider angle spray condition are used. More smaller parcels can also enhance the fuel-air reaction.