Earticle

유사비중의 범위에 있는 PVC, PET and PMMA 3종 혼합플라스틱의 마찰하전 정전선별이 2단계 분리공정을 통하여 수행되었다. PVC, PET and PMMA의 재질분리에 있어 효과적인 하전장치의 재질은 Polypropylene(PP) 과 high-impact polystyrene(HIPS) 임을 확인하였다. PP 싸이클론 하전장치를 이용한 1단계 분리공정에서, PVC의 품위와 회수율은 공기속도 10m/s, 전기장의 세기 200kV/m 이상, 분리대위치 +2cm, 상대습도 30% 이하의 조건에서 각각 99.6%와 97.5%로 구하였으며, HIPS 싸이크론 하전장치를 이용한 2단계 분리공정으로부터, 공기속도 10m/s, 전기장의 세기 250 kV/m, 분리대 위치 0cm, 상대습도 40% 이하의 조건에서 PMMA의 품위와 회수율을 각각 97.8%와 95.12%로 구하였다.

Triboelectrostatic separation of mixed three kinds of plastics, PVC, PET and PMMA, in the range of similar gravity has been performed through a two-stage separation process. Polypropylene (PP) and high-impact polystyrene (HIPS) were found to be the most effective materials for a tribo-charger in the separation of PVC, PET and PMMA. In the 1st stage using the PP cyclone charger, PVC grade and recovery depended considerably on the air velocity (10 m/s), the relative humidity (<30%), the electric field (>200 kV/m) and the splitter position (+2 cm from the center) in the triboelelctrostatic separator unit. At an optimum condition a PVC grade of 99.6% and a recovery of 97.5% was achieved. In the 2nd stage using the HIPS cyclone charger, a PMMA grade of 98.3% and a recovery of 97.0% was obtained under the conditions of 10m/s air velocity, over 250 kV/m electric field, central splitter position and less than 40% relative humidity.

세계적으로 도시화에 따른 교통 혼잡 및 자원과 에너지 부족 등 도시 문제가 점진적으로 심화될 것으로 예 상되어 기존 도시 인프라의 효율적 활용을 통해 도시문제 해결을 위한 방안의 하나로, 급격한 발전을 이루고 있는 4차산업 관련 혁신기술의 첨단 ICT(Information and Communication Technology)를 활용하여 도시문제 를 해결하고자 하는 스마트시티가 주목 을 받고 있다. 글로벌 주요도시에서도 스마트시티는 도시 문제 해결과 함께 4차 산업혁명에 대응하는 미래 발전의 동력 으로 스마트시티 정책들을 시행하고 있다. 우리 정부도 법률적으로도 유시티 법에서 스마트시티법으로 개정하 여 스마트시티를 첨단 정보통신기술을 도시기반시설에 융합시켜 다양한 분야에 혁신기술형 또는 시민 체감형 서비스를 제공함으로써 도시문제 해결과 도시민 삶의 질 향상을 위한 것으로 정의하고 있다. 본 연구는 스마트시티 국가시범도시인 부산에코델타시티를 연구대상 범위로 하여 기술수용모델(TAM)를 통해서 국가 시범도시에 적용될 기술혁신형 스마트서비스의 수용의도에 미치는 요인을 규명함으로써 체계적 인 이해와 학술적 가치를 제공하고 스마트 서비스의 도입 시 정책적 방향을 제시 하고자 하는 것이 본 연구 의 주된 목적이다. 따라서 부산에코델타시티 예정지 근처의 시민 317명을 대상으로 설문조사를 하였다. 기존 연구를 토대로 하여 스마트시티의 안전 및 생활분야의 서비스의 선호도 및 수용의도에 영향을 미치는 외적요인들을 시스템 측면, 서비스측면, 사용자 측면으로 분류하여 9가지로 설정하였다. 또한 변수들 간의 관계에 대한 21개의 연 구가설을 설정한뒤, 설문조사분석의 결과를 통해 가설을 검증하는 순서로 진행하였다. 연구결과, 총 9개의 외 적변수 중 ‘편리성’, ‘안정성’, ‘친숙도’, ‘자신감의 외적요인은 ‘지각된 유용성’을 통해 ‘수용의도’에 영항을 미치며, ‘상호작용성’, ‘편리성’, ‘신뢰성’, ‘친숙도’, ‘자신감’의 외적요인은 ‘지각된 사용이이성’을 통해 ‘수용의 도’에 영향을 미침을 실증하였다. 연구결과를 종합하면, 스마트시티 국가시범도시로서의 4차산업 관련 혁신기 술을 도입한 안전 및 생활분야의 서비스를 제공한다 하더라도, 서비스를 사용할 도시민의 입장에서 상호작용 성, 편리성, 안정성, 친숙도, 자신감 등을 제고시킬 수 있는 스마트 서비스 도입 및 개발이 무엇 보다 더 중요 하다고 할 수 있다. 이는 4차 산업혁명 혁신관련 기술들이 도시인프라에 융합되어 보편적 서비스로 실증된 사 례가 없는 현상황에서, 국가시범도시에 시민체감형 또는 혁신기술형 스마트서비스를 도입하고 개발 하려는 관 련자들에게 중요한 시사점을 제공한다.

This study explores the application of Two-stage data envelopment analysis(DEA) approach for the evaluation of R&D process which is composed of two stages such as (i)R&D stage and (ii)technology transfer stage. An usual attempt to deal with two-stage process is to apply the standard DEA model to each stage. However, such an approach may conclude that two inefficient stages lead to an overall efficient decision making unit(DMU) with the input of the first stage and outputs of the second stage. Consequently, improvement of one stage affects the efficiency status of the other, because of the presence of intermediate measures. In this study, we applied the Chen and Zhu(2004)’s model to the two-stage R&D process in order to guarantee an overall efficient two-stage process when each process is efficient, and provide a DEA projection with a set of optimal intermediate measures for inefficient DMUs. This study explores the application of Two-stage data envelopment analysis(DEA) approach for the evaluation of R&D process which is composed of two stages such as (i)R&D stage and (ii)technology transfer stage. An usual attempt to deal with two-stage process is to apply the standard DEA model to each stage. However, such an approach may conclude that two inefficient stages lead to an overall effi-cient decision making unit(DMU) with the input of the first stage and outputs of the second stage. Consequently, improvement of one stage affects the efficiency status of the other, because of the presence of intermediate measures. In this study, we applied the Chen and Zhu(2004)’s model to the two-stage R&D process in order to guarantee an overall efficient two-stage process when each process is efficient, and provide a DEA projection with a set of optimal intermediate measures for inefficient DMUs. This study explores the application of Two-stage data envelopment analysis(DEA) approach for the evaluation of R&D process which is composed of two stages such as (i)R&D stage and (ii)technology transfer stage. An usual attempt to deal with two-stage process is to apply the standard DEA model to each stage. However, such an approach may conclude that two inefficient stages lead to an overall efficient decision making unit(DMU) with the input of the first stage and outputs of the second stage. Consequently, improvement of one stage affects the efficiency status of the other, because of the presence of intermediate measures. In this study, we applied the Chen and Zhu(2004)’s model to the two-stage R&D process in order to guarantee an overall efficient two-stage process when each process is efficient, and provide a DEA projection with a set of optimal intermediate measures for inefficient DMUs.

Recently, big data has become an important foundation in the flow of the Fourth Industrial Revolution. In particular, in the financial sector, such as credit card companies, financial companies, and FinTech, high quality data are accumulated, so it is highly utilized, and job creation with related industries is expected. Against this background, the study aims to analyze how the readjustment of laws and systems for the construction and utilization of big data in the financial sector affects employment. The analysis uses annual big data-related costs and financial information for the financial insurance sector from 2013 to 2018. The Pooled OLS estimates of the employment function, which consists of investments related to financial big data, utilization of big data and sales, shows that investment and sales related to financial big data increase the number of employees. In addition, it is analyzed that companies that utilize financial big data have higher employment effects. As a result of including interaction terms after classifying each enterprise into three sectors: financial, insurance and pension industries, and financial and insurance-related services, the employment effects of big data-related investments are significant in financial and insurance-related services. Based on the results of estimating the expected employment growth rate of companies through CVM(Contingent Valuation Method) and DBDC(Double-Bound Dichotomous Choice) using the survey data, the more cumulative the investment involved, the more willing the investment in big data, and the more employees expected to increase the number of employees when big data use is activated, the more positive the employment growth is caused by the revision of the Financial Big Data Act. Using this estimate results, the average expected employment growth rate of a representative company is identified as 2.09%. Also, through CVM(Contingent Valuation Method) and DBDC(Double-Bound Dichotomous Choice), the growth rate of employment under the scenario of financial big data investments and sales growth is 2.09-3.23%. If this is applied to 769,000 employees as of 2018, the increase in employment can be seen to be 16,072~24,839 employees. There are limits to the fact that this study estimated employment effects through counterfactual approaches before the implementation of the Big Data Act. Since the employment effects of real big data-related companies may be different from the results, it is necessary to estimate the employment effects by utilizing more samples and variables. Currently, the employment effects may not be accurate due to the influence of COVID-19, but it is expected that more precise analysis will be possible after the data accumulates in the next year or two. In addition, a survey of 130 companies in the financial sector is not enough to be used as a population. If we analyze the employment effects of the revision of the Big Data Act on more companies in the next year or two, we think we can produce practical effects on the revision. Nevertheless, we think it is meaningful that this study has verified the preliminary feasibility of the amendment by analyzing its effects in advance before the actual bill is passed.

This study explores the application of Two-stage data envelopment analysis(DEA)approach for the evaluation of R&D process which is composed of two stages such as (i)R&D stage and (ii)technology transfer stage. An usual attempt to deal with two-stage process is to apply the standard DEA model to each stage. However, such an approach may conclude that two inefficient stages lead to an overall efficient decision making unit(DMU)with the input of the first stage and outputs of the second stage. Consequently, improvement of one stage affects the efficiency status of the other, because of the presence of intermediate measures. In this study, we applied the Chen and Zhu(2004)'s model to the two-stage R&D process in order to guarantee an overall efficient two-stage process when each process is efficient, and provide a DEA projection with a set of optimal intermediate measures for inefficient DMUs.

Angelica gigas is a common traditional medicinal plant that has been used for more than several thousand years in Korea. The commonly used Angelica roots showed pharmacological properties with their chemical compositions. The main chemical constituents of Angelica are decursin, decursinol angelate, angelicide, brefeldin A, succinic acid and adenine(2). Main constituents associated with the pharmacological activities of Angelica roots had anticancer activity(1), inhibitor of platelet aggregation, antiasthmatic and spasmolytic activities(2). The economic feasibility of production by plant cell culture is primarily determined by productivity. It has been argued that optimization of biomass growth and product formation must be evaluated as to the possibility of implementation in a large-scale process(3). One of solutions was a two-stage process. We have changed hormone condition of Angelica gigas cell culture for two-stage culture. After analyzing intracellular compounds of our Angelica gigas cell line, we have validated to increase several secondary metabolites after changing culture medium. In this study, we suggest that two-stage process of plant cell culture is a good system for secondary metabolites production.

The importance of polysaccharides is increasing globally due to their role as a significant source of dietary prebiotics in the human diet. In the present study, in order to maximize the yield of crude polysaccharides from Pinus densiflora, response surface methodology (RSM) was used to optimize a two-stage extraction process consisting of steam explosion and water extraction. Three independent main variables, namely, the severity factor (Ro) for the steam explosion process, the water extraction temperature ($^{\circ}C$), and the ratio of water to raw material (v/w), were studied with respect to prebiotic sugar content. A Box-Behnken design was created on the basis of the results of these single-factor tests. The experimental data were fitted to a second-order polynomial equation for multiple regression analysis and examined using the appropriate statistical methods. The data showed that both the severity factor (Ro) and the ratio of water to material (v/w) had significant effects on the prebiotic sugar content. The optimal conditions for the two-stage process were as follows: a severity factor (Ro) of 3.86, a water extraction temperature of $89.66^{\circ}C$, and a ratio of water to material (v/w) of 39.20. Under these conditions, the prebiotic sugar content in the extract was 332.45 mg/g.

This study aimed to develop a novel anaerobic two-stage process converting food waste to $H_2$ and $CH_2$. The anaerobic two-stage process was devised by combining hydrogen fermentation with methane fermentation. At the high loading rate of 12.3 kg $Vs/m^3/d$, it could remove 72.5%of VS and convert $VS_{removed}$ to $H_2$ (28.2%) and $CH_4$ (69.9%) on COD basis in 8 days.

유사비중의 범위에 있는 PVC, PET and PMMA 3종 혼합플라스틱의 마찰하전 정전선별이 2단계 분리공정을 통하여 수행되었다. PVC, PET and PMMA의 재질분리에 있어 효과적인 하전장치의 재질은 Polypropylene(PP) 과 high-impact polystyrene(HIPS) 임을 확인하였다. PP 싸이클론 하전장치를 이용한 1단계 분리공정에서, PVC의 품위와 회수율은 공기속도 10 m/s, 전기장의 세기 200 kV/m 이상, 분리대 위치 +2cm, 상대습도 30% 이하의 조건에서 각각 99.6%와 97.5%로 구하였으며, HIPS 싸이크론 하전장치를 이용한 2단계 분리공정으로부터, 공기속도 10 m/s, 전기장의 세기 250 kV/m, 분리대 위치 0cm, 상대습도 40% 이하의 조건에서 PMMA의 품위와 회수율을 각각 97.8%와 95.12%로 구하였다.

Triboelectrostatic separation of mixed three kinds of plastics, PVC, PET and PMMA, in the range of similar gravity has been performed through a two-stage separation process. Polypropylene (PP) and high-impact polystyrene (HIPS) were found to be the most effective materials for a tribo-charger in the separation of PVC, PET and PMMA. In the 1st stage using the PP cyclone charger, PVC grade and recovery depended considerably on the air velocity (10 m/s), the relative humidity (<30%), the electric field (>200 kV/m) and the splitter position (+2 cm from the center) in the triboelelctrostatic separator unit. At an optimum condition a PVC grade of 99.6% and a recovery of 97.5% was achieved. In the 2nd stage using the HIPS cyclone charger, a PMMA grade of 98.3% and a recovery of 97.0% was obtained under the conditions of 10m/s air velocity, over 250 kV/m electric field, central splitter position and less than 40% relative humidity.

The state of the art of the 2-stage swirl calciner is to make 2-stage counter gas flow in a calciner with cooler hot air. Gas flow in the calciner increases retention time of raw mix particles. Simple structure of the 2-stage swirl calciner operated optimally the rotary cement kiln. In this study, in order to decide the entrance type of the cooler air of the optimal calciner model, an entrance cooler air velocity, the input points of raw mix were analyzed in many aspects with cold model experiment and computational fluidized dynamic simulation. It was found that the entrance type of cooler air fully splite 2-stage for the optimal condition of the cold model calciner. The operation conditions were that the input feeding, the cooler air velocity and the air velocity of throat were 0.33kg/$\textrm m$3$, 15m/s and 20m/s respectively. The performance of 150 t/d the pilot plant connected with the kiln rising duct was that volume capacity of the calciner is over 430 kg/$\textrm m$3$-h, decarbonation rate of raw mix apparently 90%, heat consumption 950 kcal/kg-cli and retention time of raw mix 2.4 sec. Its the best operating condition is cooler air velocity 18m/s, the gas velocity of throat 25m/s, feeding rate of raw mix 10t/h. The operating experience of the pilot plant confirmed the success of scale up for over 3000 t-cli/d.

In contrast to some prominent methodologists maintain that the practice of economic theory-building follows a regularist methodology, this paper defends a capacity-based analytic piecemeal image of the so-called causal structuralist approach of theory-building in economics. This piecemeal image indicates that the process of restructuring the theoretical model in economics reflects a general picture of economic theorizing by showing that the failed predictions obtained from a two-stage-theory-test process constitute a piece of information that is fed back to the theoretical model as a clue to help economists manipulate a rearrangement of the model. By conducting such a model-rearrangement, economists can thus provide empirical content to their models in the process of theory-building with respect to various concrete cases; and this piecemeal characterization of the approach should be regarded as arising from the fact that although economists have a holistic view of the causal structure of an economic phenomenon, they do not have a holistic approach to obtain the causal structure, what they can do is to try their very best to use the capacity-based analytic piecemeal method to uncover the causal structure case by case and step by step.

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD₅₄₀ = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.

This work presents a 2-stage distributed amplifier (DA) and a 2-stage cascaded single-stage distributed amplifier (CSSDA) in Samsung 65 nm CMOS technology. They are designed in cascode configuration to obtain broad bandwidth and high gain, and m-derived filter configuration is used for compact layout. The measurement results show a peak gain of 10 dB of 2-stage DA and 13 dB of 2-satge CSSDA with the 3-dB bandwidth from 5 GHz to 20 GHz. S11 and S22 are better than -10 dB over the entire bandwidth. The chip sizes are 720 × 540 μm2 and 580 × 450 μm2 for the 2-stage DA and the 2-stage CSSDA, respectively.

The production part requiring multiple processes such as piecing, blanking and notching are performed with a high production rates in progressive die. In order to prevent the defects of process result, the optimum of strip process layout design, die design, die making, and tryout with inspection etc. are needed. According to these factors of die development process, they required theory and practice of metal working process and its background, die structure, machining conditions for die making, die materials, heat treatment of die components, know-how and so on. In this study, we designed and analyzed die components also simulated the strip process layout of multiple stage drawing by DEFORM. Especially the result of tryout and its analysis become to the feature of this study.

토양의 규산 흡착기작을 밝히고자 continuous stirred-flow(연속진탕흘림) 법을 이용하여 시간 경과에 따른 규산 흡착량 변화에 대한 실험을 $25^{\circ}C$, pH 3수준(5, 6.5, 8)에서 실시하였다. 규산 흡착량은 실험기간내 최대 흡착량을 보이지 않고 계속 증가 하였다. 시간에 따른 규산의 흡착과정을 2단계로 구분 하였고, 1단계 반응과정은 아래의 지수함수식에서 고도의 유의성있는 상관관계를 보였다 $$R_{ad}=K_a*(Q_{OH}^S)^n$$ 여기서 $R_{ad}$는 규산흡착속도($Si\;{\mu}mal/min$), $Q_{OH}^S$는 알칼리 투여를 통하여 생성된 토양표면 음전하량, $K_a$와 n 은 상수이다. 1단계 반응과정의 n값은 1.1로 한자리 결합(monolantate ligand bonding)에 의한 흡착과정인 것으로 나타났다. 2단계 과정은 아래 식에서 고도의 유의성있는 상관관계를 보였다. $$R_{ad}=K_b*(pH)$$ 이때 $K_b$ 는 비례상수로, pH 증가에 따른 규산 흡착 속도의 증가 추세가 지수 함수적으로 감소하는 경향을 보였다.

To clarify the mechanism of silica adsorption to soil, kinetic study using continuous stirred-flow method was conducted with the Luisiana soil at three pH levels (pH 5.0, 6.5, and 8.0). Silica adsorption increased continuously without showing the maximum adsorption for long enough experimental time. Kinetic curve of silica adsorption could be divided into two stage processes. The first stage process was fitted well to the following equation with highly significant correlation coefficient : $$R_{ad}=K_a*(Q_{OH}^S)^n$$ where, $R_{ad}$ is silica adsorption rate($Si\;{\mu}mal/min$). $Q_{OH}^S$ is the negative charge sites on the soil surface created by alkali titration, and $K_a$ and n are constants. The "n" value of the first stage process was 1.1. This value indicates that the silica adsorption is accomplished by the monodendate ligand bonding. The second stage process was fitted well to the following equation : $$R_{ad}=K_b*(pH)$$ where, $K_b$ is a constant. The equation indicates that the silica adsorption is not proportional to the $OH^-$ ion concentration. Rather, the increasing pattern of silica adsorption rate with the increase of $OH^-$ ion concentration would decrease exponentially.

고체가 연속적으로 주입되고 배출되는 상온 상압 2단 기포 유동층(내경 0.1 m, 높이1.2 m)의 흐름특성을 조사하고, 운전유속범위를 고찰하였다. 고체는 상부 기포 유동층으로 주입되고, 넘쳐서 기계적 혹은 비기계적 밸브가 없이 단순히 농후상 고체 층으로 이루어진 고체 수송관(standpipe, 내경 0.025 m)를 통하여 하부 기포 유동층의 층으로 주입되며, 하부 유동층을 넘쳐서 고체가 배출되었다. 기체는 하부 유동층을 유동화하고 배출된 후 다시 상부 유동층을 유동화하였다. 기체로는 공기를 사용하였고, 고체로는 입도가 큰 입자(< $1000{\mu}m$, 겉보기 밀도 $3090kg/m^3$)와 입도가 작은 입자(< $100{\mu}m$, 겉보기 밀도 $4400kg/m^3$)를 혼합한 입자를 사용하였으며, 혼합비를 변수로 하였다. 하부 유동층 기체가 고체수송관의 고체흐름을 비우고, 우회하는 조건일 때 하부 유동층 유동화 속도를 붕괴속도로 정의하였다. 본 공정의 운전이 가능한 최대기체유속으로 붕괴속도가 사용될 수 있었다. 붕괴속도는 작은 입자 혼합비가 증가함에 따라 증가하여, 30%에서 가장 큰 값을 나타낸 후, 감소하였다. 붕괴속도의 경향은 고체수송관 상단과 하단 사이의 압력차 경향과 유사하였다. 붕괴속도는 벌크밀도(bulk density)와 정체층 공극률의 함수로 나타내졌으며, 벌크밀도가 증가하면 증가하고, 정체층 공극률이 증가하면 감소하였다.

Flow characteristics and the operating range of gas velocity was investigated for a two-stage bubbling fluidized-bed (0.1 m-i.d., 1.2 m-high) that had continuous solids feed and discharge. Solids were fed in to the upper fluidized-bed and overflowed into the bed section of the lower fluidized-bed through a standpipe (0.025 m-i.d.). The standpipe was simply a dense solids bed with no mechanical or non-mechanical valves. The solids overflowed the lower bed for discharge. The fluidizing gas was fed to the lower fluidized-bed and the exit gas was also used to fluidize the upper bed. Air was used as fluidizing gas and mixture of coarse (< $1000{\mu}m$ in diameter and $3090kg/m^3$ in apparent density) and fine (< $100{\mu}m$ in diameter and $4400kg/m^3$ in apparent density) particles were used as bed materials. The proportion of fine particles was employed as the experimental variable. The gas velocity of the lower fluidized-bed was defined as collapse velocity in the condition that the standpipe was emptied by upflow gas bypassing from the lower fluidized-bed. It could be used as the maximum operating velocity of the present process. The collapse velocity decreased after an initial increase as the proportion of fine particles increased. The maximum took place at the proportion of fine particles 30%. The trend of the collapse velocity was similar with that of standpipe pressure drop. The collapse velocity was expressed as a function of bulk density of particles and voidage of static bed. It increased with an increase of bulk density, however, decreased with an increase of voidage of static bed.

본 연구에서는 목질계 바이오매스인 돼지감자 줄기에 대한 전처리 공정을 수행하였다. 공정은 효소 당화 수율을 높이기 위하여 흐름형 침출 전처리 공정에 2단 전처리 공정으로 적용하였다. 전처리 용매로 암모니아수에 의한 탈 리그닌 효과와 황산 용액에 의한 헤미셀룰로오스의 분해가 효소당화 및 발효에 미치는 영향을 확인하였다. 암모니아수와 황산용액을 이용한 2단 전처리 공정을 수행하였다. 먼저 1단계 공정은 40분 동안 $163.2^{\circ}C$의 온도에서 암모니아수로 처리를 진행하였고 다음 2단계 공정은 $169.7^{\circ}C$에서 20분 동안 황산 용액으로 처리를 수행하여 물질수지를 구하였다. 그리고 앞의 공정과 반대의 순서로 황산 용액을 먼저 처리한 후 암모니아수를 처리한 2단 전처리 공정을 수행하였다. 이때 암모니아수를 먼저 처리한 공정에서 글루코오스 생산량은 30.7 g으로 72.4%의 수율이 나타났다. 반대로 황산 용액을 먼저 처리한 후 암모니아수를 처리한 2단 전처리 공정에서는 글루코오스 생산량이 20.9 g으로 49.3%의 수율을 보였다.

In this study, the pretreatment of Helianthus tuberosus residue had been performed. The two-stage pretreatment on flow-through process were applied in the interests of increase of sugar production yield on enzymatic saccharification. The delignification by aqueous ammonia and the fractionation of hemicellulose by sulfuric acid solution as pretreatment solution were confirmed for effects of enzymatic saccharification. Two-stage pretreatment process was performed using aqueous ammonia and sulfuric acid. The first step was performed with aqueous ammonia for 40 min at $163.2^{\circ}C$ and the second step was performed with sulfuric acid solution for 20 min at $169.7^{\circ}C$. And then, the first step was performed with sulfuric acid solution and the second step was pretreated with aqueous ammonia. At this time, the glucose production was 30.7 g and the glucose yield was 72.4% in the first step process with aqueous ammonia. And, the glucose production was 20.9 g and the glucose yield was 49.3% in the first step process with sulfuric acid solution.

It is estimated that only heating and cooling take about one third of the total energy consumption worldwide. However, the conventional heating and cooling systems have low efficiencies. Also, boilers and electric heaters that are mostly used to generate both domestic and industrial hot water are inefficient and high energy consumers. For this reason, cascade heat pumps which are known to be very energy efficient and have less environmental impact are being promoted to replace conventional heating, cooling and hot water systems. In this study, a newly designed cascade heat pump by two-stage water heating method has been experimentally investigated. By adopting the auxiliary heat exchanger, the performance of the system was increased. The performance enhancement rate of the system could be maximized by adjusting the low stage compressor speed rather than the high stage compressor speed. The performance of the system with the auxiliary heat exchanger was enhanced by 16.5%.

In this study, we try to understand the role of online social recommendation and the similarity of preferences between the recommender and the recommendee on consumer decisions in the framework of the two stage purchase decision-making process. Applying construal level theory to our context, we expect that the role of social recommendation and the similarity of preferences would vary over the stages in the two-stage decision making process. To test our hypotheses, we collected the data through an incentive compatible experiment, and analyzed the data with nested logit model. As a result, we found that the role of online social recommendation varies over the stages. Consumers take recommendation from similar others at the stage of consideration set formation, but no longer consider it at the stage of final choice. Consumers take recommendation from dissimilar others at the stage of consideration set formation. At the stage of final choice, however, consumers avoid choosing the option recommended by dissimilar others. The results of our study enrich the understanding about the role of social recommendation, and have implication to marketing practitioners who attempt to make online social recommendation system more efficient.

In order to demonstrate a target reliability with a specified confidence level, a new two-stage Bayesian Reliability Demonstration Test (RDT) plans that is known to be more effective than a corresponding single-stage one is proposed and developed by Bayesian framework with beta prior distribution for Weibull life time distribution. A numerical example is provided to illustrate the proposed RDT plans and compared with other non-Bayesian and Bayesian plans. Comparative results show that the proposed Bayesian two-stage plans have some merits in terms of required and expected testing time and probability of acceptance.