• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.223-233
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• 2013

The purpose of this study was to analyze the dietary habits and perception of vegetable intake of elementary students in Gwangju and Jeonnam Gokseong county. Data collection was conducted from 5th and 6th grade students of elementary schools in Gwangju and Jeonnam Gokseong county using a structured questionnaire survey. The SPSS program was used for statistics processing and data analysis. The chi-square test was also conducted. In terms of dietary intake habits, female students consumed their meals slower than male students. Information on dietary habits and nutrition was commonly obtained from family, including the mother or father who commonly prepared meals at home. Snacks were commonly consumed less than twice daily, with the Gwangju area having a higher frequency of snacks than the Jeonnam area. Elementary students indicated that vegetables were their least favorite food, with female students having a higher interest in vegetables than male students. The pattern and perception of vegetable intake came when the students (that did not eat vegetables) were lectured by their parents on the nutritive value of vegetables. Most students understood the important nutritional ingredients of vegetables. In the case of an interest in vegetables, the Gwangju area showed significantly more comprehension than the Jeonnam area on the definition and role of dietary fiber, the dental benefits of dietary fiber, and the identification of the environment-friendly certification mark.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.200-206
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• 2009

Purpose: The incidence of upper gastric cancer and especially the diffuse type have increased in western countries. The aim this study was to investigate the chronologic changes of the clinicopathological features and survival rates of Korean upper gastric cancer patients. Materials and Methods: 1,638 gastric cancer patients who underwent gastrectomy were included in this study and they were divided into two groups; the 1990's (1991~1999, n=987) and the early 2000's (2000~2003, n=651). We evaluated the differences of the clinicopathologic features and the factors that affected the survival rates by univariative and multivariative analysis. Results: The older age (>60) patients increased from 42.7% to 50.7% respectively. Being overweight (body mass index$\geq$23) also increased from 31.5% to 43.2%. For the pathology, the incidence of stage Ia gastric cancer increased (29.8% to 44.5%) and the incidence of stage IV gastric cancer decreased (23.5% to 11.8%). Yet there was no difference according to the WHO classification, Lauren's classification and the location of tumor between the groups. The 5 year survival rates increased 67.7% to 83.7%, according to the group. Multivariative analysis showed that the odd ratios of the early 2000s was 0.715 (95% CI; 0.555~0.921) as compared to that of the 1990s. Conclusion: There were no changes of the clinicopathologic features, like the pattern in western countries, although the incidence early gastric cancer, old age patients and overweight patients increased. The survival rate of early 2000s was better that that of the 1990s.

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.70-78
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• 2008

Purpose: VEGF-C and VEGF-D are angiogenetic factors, and abnormal expression of E-cadherin hasa role in the progression of gastric carcinoma. The aim of this study was to evaluate the relationship between the expression of E-cadherin, VEGF-C and VEGF-D with the presence of lymph node metastases (LNM) using cytokeratin 18 in early gastric cancer (EGC). Materials and Methods: Immunohistochemical staining for E-cadherin, VEGF-C and VEGF-D was performed in 49 EGC patients from March 1997 to December 2002. To evaluate the real extent of LNM, 1,562 lymph nodes from 49 patients were re-examined with the use of cytokeratin 18. Results: Eleven (0.7%) LNM were newly found in 12.2% (n=6) of patients. The real LNM rate was 3.6% in mucosal invasive (m) cancer and 38.1% in submucosal invasive (sm). Stage migration was seen in three patients (6.1%). Abnormal expression of E-cadherin was detected in 36.7% of the patients and expression of VEGF-C and VEGF-D was detected in 16.3% and 36.7% of the patients, respectively. Abnormal expression of E-cadherin was significantly correlated with tumor differentiation (P=0.0103) and Lauren classification (P<0.0001). There was no positive relationship of VEGF-C and VEGF-D expression with the clinicopathological findings for EGC including LNM. However, the frequency of lymph node metastases was significantly higher in patients that demonstrated abnormal expression of E-cadherin with positive immunoreactivity of VEGF-C or VEGF-D (P=0.031). Conclusion: In present study, we could not demonstrate a relationship between the presence of LNM and expression of VEGF-C and VEGF-D in EGC. However, VEGF-C or VEGF-D expression, in addition to the abnormal expression of E-cadherin, was correlated with the real extent of LNM in EGC.

• Journal of the Korean GEO-environmental Society
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• v.19 no.4
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• pp.5-16
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• 2018

In the current study, the engineering behaviour of prebored and precast steel pipe piles was examined from a series of full-scale field measurements by conducting static pile load tests, dynamic pile load tests (EOID and restrike tests) and Class-A and Class-C1 type numerical analysis. The study includes the pile load - settlement relations, allowable pile capacity and shear stress transfer mechanism. Compared to the allowable pile capacity obtained from the static pile load tests, the dynamic pile load tests and the numerical simulation showed surprisingly large variations. Overall among these the restrike tests displayed the best results, however the reliability of the predictions from the numerical analysis was lower than those estimated from the dynamic pile load tests. The allowable pile capacity obtained from the EOID tests and the restrike tests indicated 20.0%-181.0% (avg: 69.3%) and 48.2%-181.1% (avg: 92.1%) of the corresponding measured values from the static pile loading tests, respectively. Furthermore, the computed results from the Class-A type analysis showed the largest scatters (37.1%-210.5%, avg: 121.2%). In the EOID tests, a majority of the external load were carried by the end bearing pile capacity, however, similar skin friction and end bearing capacity in magnitude were mobilised in the restrike tests. The measured end bearing pile capacity from the restrike tests were smaller than was measured from the EOID tests. The present study has revealed that if the impact energy is not sufficient in a restrike test, the end bearing pile capacity most likely will be underestimated. The shear stresses computed from the numerical analysis deviated substantially from the measured pile force distributions. It can be concluded that the engineering behaviour of the pile is heavily affected if a slime layer exists near the pile tip, and that the smaller the stiffness of the slime and the thicker the slime, the greater the settlement of the pile.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.505-512
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• 2006

Characteristics of particle holdup and heat transfer were investigated in a liquid-particle swirling fluidized bed whose diameter was 0.102 m and 2.5 m in height. Effects of liquid velocity, particle size and swirling liquid ratio($R_s$) on the particle holdup and immersed heater-to-bed overall heat transfer coefficient were examined. The particle holdup increased with increasing particle size and swirling liquid ratio but decreased with increasing liquid velocity.The local particle holdup was relatively high in the region near the heater when the $R_s$ value was 0.1~0.3, but the radial particle holdup was almost uniform when the $R_s$ value was 0.5, whereas, when the $R_s$ value was 0.7, the local particle holdup was relatively low in the region near the heater. The heat transfer characteristics between the immersed heater and the bed was well analyzed by means of phase space portraits and Kolmogorov entropy(K) of the time series of temperature difference fluctuations. The phase space portraits of temperature difference fluctuations became stable and periodic and the value of Kolmogorov entropy tended to decrease with increasing the value of $R_s$ from 0.1 to 0.5. The Kolmogorov entropy exhibited its maximum value with increasing liquid velocity. The value of overall heat transfer coefficient(h) showed its maximum value with the variation of liquid velocity, bed porosity or swirling liquid ratio, but it increased with increasing particle size. The value of K exhibited its maximum at the liquid velocity at which the h value attained its maximum. The particle holdup and overall heat transfer coefficient were well correlated in terms of dimensionless groups of operating variables.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.581-584
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• 2008

The catalyst carriers of the mesoporous layer compounds were prepared to carry out the partial oxidation of methane(POM) to hydrogen. The catalytic activities of POM to hydrogen were investigated over Ru(3)/SPK and Ru(3)/SPM catalyst in a fixed bed flow reactor under atmosphere. In addition, the catalysts and carriers were characterized by BET, TEM, TPR. The BET surface areas of the silica-pillared $H^+-kenyaite$(SPK) and the silica-pillared $H^+-magadite$(SPM) were $760m^2/g$ and $810m^2/g$, repectively, and the average pore sizes were 3.0 nm and 2.6 nm, repectively. The nitrogen adsorption isotherms were type IV with developed hysteresis. The TEM showed that the mesoporous layer compounds were formed well. The Ru(3)/SPK and the Ru(3)/SPM catalyst were obtained high hydrogen yields(90%, 87%), and were kept constant high hydrogen yields even about 60 hours at 973 K, $CH_4/O_2=2$, $1.25{\times}10^{-5}g-Cat.hr/ml$. The TPR peaks of Ru(3)/SPK and the Ru(3)/SPM catalyst showed the similar reducibilities around 453 K and 413 K. It could be suggested that SPK and SPM had the physicochemical properties as oxidation catalyst carries from these analysis data.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.31-38
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• 2015

At present, carbon dioxide ($CO_2$) emission, which causes global warming, is a major issue all over the world. To reduce $CO_2$ emission directly, commercial deployment of $CO_2$ separation processes has been attempted in industrial plants, such as power plant, oil refinery and steelmaking plant. Besides, several studies have been done on indirect reduction of $CO_2$ emission from recycle of reducing gas (carbon monoxide or hydrogen containing gas) in the plants. Unlike many competing gas separation technologies, pressure swing adsorption (PSA) and membrane filtration are commercially used together or individually to separate a single component from the gas mixture. However, there are few studies on operation of sequential separation process of multi-component gas which has more than two target gas products. In this paper, process simulation model is first developed for two available configurations: $CO_2$ PSA-CO PSA-$H_2$ PSA and $CO_2$ PSA-CO PSA-$H_2$ membrane. Operation optimization and economic evaluation of the processes are also performed. As a result, feed gas contains about 14% of $H_2$ should be used as fuel than separating $H_2$, and $CO_2$ separation should be separated earlier than CO separation when feed gas contains about 30% of $CO_2$ and CO. The simulation results can help us to find an optimal process configuration and operation condition for separation of multicomponent gas with $CO_2$, CO, $H_2$ and other gases.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.980-987
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• 2012

Nonpoint source pollution causes leaks and overtopping, depending on the state of the sewer network as well as aggravates the pollution load of the aqueous water system as it is introduced into the sewer by wash-off. According, the need for efficient sewer monitoring system which can manage the sewage flowrate, water quality, inflow/infiltration and overflow has increased for sewer maintenance and the prevention of environmental pollution. However, the sewer monitoring is not easy since the sewer network is built in underground with the complex nature of its structure and connections. Sewer decontamination mechanism as well as pipe network monitoring and fault diagnosis of water network system on system analysis proposed in this study. First, the pollution removal pattern and behavior of contaminants in the sewer pipe network is analyzed by using sewer process simulation program, stormwater & wastewater management model for expert (XP-SWMM). Second, the sewer network fault diagnosis was performed using the multivariate statistical monitoring to monitor water quality in the sewer and detect the sewer leakage and burst. Sewer decontamination mechanism analysis with static and dynamic state system results showed that loads of total nitrogen (TN) and total phosphorous (TP) during rainfall are greatly increased than non-rainfall, which will aggravate the pollution load of the water system. Accordingly, the sewer outflow in pipe network is analyzed due to the increased flow and inflow of pollutant concentration caused by rainfall. The proposed sewer network monitoring and fault diagnosis technique can be used effectively for the nonpoint source pollution management of the urban watershed as well as continuous monitoring system.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1068-1075
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• 2012

Poly(butylene terephthalate) (PBT)/Nylon6,12 core/shell micro fiber were prepared by extrusion molding. To investigate their optimum extrusion conditions, compatibility of PBT/Nylon6,12 blend micro fiber in conformity to their weight ratio and manufacture temperature was explored with SEM morphology and DSC. The alterations in their mechanical properties by extrusion speed were compared and analyzed through a UTM. In comparison with SEM figures, the domain sizes of Nylon6,12 were gradually declined by increasing the extrusion temperature of blends. Furthermore, according to these SEM images, the phase separation between Nylon6,12 domain and PBT matrix became indistinct with increasing of weight percentage of Nylon6,12. In case of DSC, the boundaries of two peaks were almost disappeared when increasing the extrusion temperature and also intervals of each two melting peaks became narrow as increasing the Nylon6,12 ratio. The mechanical properties including tensile strength, elongation, flexural strength and flexural modulus were increased as the increase in the extrusion temperature until $260^{\circ}C$. However, the mechanical properties were actually deteriorated over $260^{\circ}C$. The tensile strength, elongation, flexural strength and flexural modulus at $260^{\circ}C$ were 560 $kg_f/cm^2$, 220%, 807 $kg_f/cm^2$ and 22,146 $kg_f/cm^2$, respectively. These values are more than intermediate values of mechanical properties of PBT and Nylon6,12. These results mean that there is compatibility between PBT and Nylon6,12. Based on the extrusion conditions that produced optimum compatibility of blend, as a result, our group obtained micro fibers with the core/shell structure.