• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.584-592
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• 2004

A thermostable $\beta$-glycosidase gene, tfi $\beta$-gly, was cloned from the genomic library of Thermus filiformis Wai33 A1. ifi $\beta$-gly consists of 1,296 bp nucleotide sequence and encodes a polypeptide of 431 amino acids. It shares a strong amino acid sequence similarity with the $\beta$-glycosidases from other Thermus spp. belonging to the glycosyl hydrolase family 1. In the present study, the enzyme was overexpressed in Escherichia coli BL21 (DE3) using the pET21b(+) vector system. The recombinant enzyme was purified to homogeneity by heat treatment and a $Ni^{2+}$-affinity chromatography. Polyacrylamide gel electrophoresis (PAGE) showed that the recombinant Tfi $\beta$-glycosidase was a monomeric form with molecular mass of 49 kDa. The temperature and pH range for optimal activity of the purified enzyme were 80- $90^{\circ}C$ and 5.0-6.0, respectively. Ninety-three percent of the enzyme activity was remained at $70^{\circ}C$ after 12 h, and its half-life at $80^{\circ}C$ was 6 h, indicating that Tfi $\beta$-glycosidase is highly thermostable. Based on its K_m$, or $K_{cat}K_m$, ratio, Tfi $\beta$-glycosidase appeared to have higher affinity for $\beta$-D-glucoside than for $\beta$-D-galactoside, however, $K_{cat} for \beta$-D-galactoside was much higher than that for $\beta$-D-glucoside. The activity for lactose hydrolysis was proportionally increased at $70^{\circ}C$ and pH 7.0 without substrate inhibition until reaching 250 mM lactose concentration. The specific activity of Tfi TEX>$\beta$-glycosidase on 138 mM lactose at $70{^\circ}C$ and pH 7.0 was 134.9 U/mg. Consequently, this newly cloned enzyme appears to have a valuable advantage of conducting biotechnological processes at elevated temperature during milk pasteurization in the production of low-lactose milk.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제41권4호
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• pp.263-270
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• 2017

The shipbuilding industry uses large stationary tanks to store low-pressure air, which is used to open and close large shut-off valves. However, when supplying air from the tank to a distant valve, there are problems related to the need for supplementary pipes and the pressure drop during transportation. In this study, a portable welded vessel for storing high-pressure nitrogen (11 kg, 10 L, and 50 bar) was designed to prevent air leakage and improve the convenience of workers. This pressure vessel was elliptical to reduce the number of welded parts, which are structurally weak. The thickness and ratio of the major and minor axes of the pressure vessel were calculated to verify its structure stability at the working pressure (50 bar), and that the proposed weight and capacity were satisfactory. The residual stress caused by the welding process was calculated by performing a transient thermal-structural coupled field analysis using the ANSYS parametric design language (APDL), and the fatigue life of the vessel was verified based on the Goodman criterion.

• The Journal of Korean Academy of Prosthodontics
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• 제31권3호
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• pp.423-446
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• 1993

Titanium and its alloys are finding increasing use in medical devices and dental implants. The strong selling point of titanium is its resistance to the highly corrosive body fluids in which an implant must survive. This corrosion resistance is due to a tenacious passive oxide or film which exists on the metal's surface and renders it passive. Potentiodynamic polarization measurement is one of the most commonly used electro-chemical methods that have been applied to measure corrosion rates. And the potentiodynamic polarization test supplies detailed information such as open circuit, rupture, and passivation potential. Furthermore, it indicates the passive range and sensitivity to pitting corrosion. This study was designed to compare the corrosion resistance of the commonly used dental implant materials such as CP Ti, Ti-6A1-4V, Co-Cr-Mo alloy, and 316L stainless steel. And the effects of galvanic couples between titanium and the dental alloys were assessed for their useful-ness-as. materials for superstructure. The working electrode is the specimen , the reference electrode is a saturated calomel electrode (SCE), and the counter electrode is made of carbon. In $N_2-saturated$ 0.9% NaCl solutions, the potential scanning was performed starting from -800mV (SCE) and the scan rate was 1 mV/sec. At least three different polarization measurements were carried out for each material on separate specimen. The galvanic corrosion measurements were conducted in the zero-shunt ammeter with an implant supraconstruction surface ratio of 1:1. The contact current density was recorded over a 24-hour period. The results were as follows : 1. In potential-time curve, all specimens became increasingly more noble after immersion in the test solution and reached between -70mV and 50mV (SCE) respectively after 12 hours. 2. The Ti and Ti alloy in the saline solution were most resistant to corrosion. They showed the typical passive behavior which was exhibited over the entire experimental range. Therefore no breakdown potentials were observed. 3. Comparing the rupture potentials, Ti and Ti alloy had the high(:st value (because their break-down potentials were not observed in this study potential range ) followed by Co-Cr-Mo alloy and stainless steel (316L). So , the corrosion resistance of titanium was cecellent, Co-Cr-Mo alloy slightly inferior and stainless steel (316L) much less. 4. The contact current density sinks faster than any other galvanic couple in the case of Ti/gold alloy. 5. Ag-Pd alloy coupled with Ti yielded high current density in the early stage. Furthermore, Ti became anodic. 6. Ti/Ni-Cr alloy showed a relatively high galvanic current and a tendency to increase.

• Journal of the Korean Institute of Landscape Architecture
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• 제38권5호
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• pp.31-41
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• 2010

This research aims to present a methodological approach for repurposing small pockets of national/public lands, which can be constructed as parks, through an investigation of the present status of these areas of national/public lands that are scattered around Busan Megalopolis as well as the suitability of their construction. In order to attain this, this study looked at the present status of these small areas of national/public lands by utilizing a national land, city land list (lot number), land registration map and satellite image of Busan Megalopolis, and evaluating their suitability as parks through GIS analysis and classification. As a result, these small areas of lands with the potential to be turned into parks include 516 spots($375,934m^2$). Geographically, 39% of these areas are located on flat land and are the most scattered. 260 places met the requirements for optimal placement for conversion, while convenience included 305 places, and availability 267 places. The most optimal of the places meeting such standards include 61 spots. The characteristics of these areas of national/public lands include being below $500m^2$, with flatlands and open areas above a 5' grade occupy the highest ratio, accounting for 25.4% of the land studied. These results have offered a methodology for a GIS DB, which can visualize the data for a positive utilization be yond the simple level of the maintenance/preservation of national/public lands and provide basic data for the utilization and management of these types of areas in the future.

• Journal of Korea Soil Environment Society
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• 제3권1호
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• pp.31-44
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• 1998

The geochemical experiments were carried out to investigate a removal effect of heavy metals in abdndoned metallic mine wastes, and to conceive a treatment techniques of them. In order to prevent contamination, experiment appature was made of acrylic acid resin and polyethylene which resist to acid and alkali. Experiment models are devided into four groups based on the system environments, distribution patterns and a kind of filling materials. The first group is background model(model I ) which is filled with waste only and opened to air. The second one is four layer group which is subdivided into two models, opened and closed systems, and the third mix group which is subdivided into three models based on mixing ratio of filling materials and system environment like a layered group. The forth is composed of two layer model, lower one composed of waste and upper one limestone chips. Solution drained from Model Ishows a high contents of heavy metals on the all terms of experiments. Among the models, however, the closed mix model V and Ⅶ show the most effective removal of heavy metals liberated from wastes. Models having different mixing ratios of filling materials on closed systems does not affect in heavy metal removal effect. But, the distribution patterns of filling materials affect very much on removal effect of heavy metals. The closed models with same constitution ratios and distribution patterns of filling materials show more and less effective removal to the open models.

• Polymer(Korea)
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• 제37권6호
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• pp.694-701
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• 2013

A new copolymer named T-TI24T (poly((5,5-(2-butyl-5,6-bisdecyloxy-4,7-di-thiophen-2-yl-isoindole-1,3-dione))- alt-(2,5-thiophene))) based on phthalimide derivative and thiophene is synthesized by the Stille-coupling reaction. The polymer shows relatively high number average molecular weight of 86500 g/mol with good solubility in common organic solvents such as chloroform, 1,2-dichlorobenzene, and toluene and is thermally stable up to $380^{\circ}C$. Besides, it possesses a relatively low highest occupied molecular orbital (HOMO) energy level of -5.33 eV, promising the high open circuit voltage ($V_{oc}$) for photovoltaic applications. Active layer solution of polymer T-TI24T-as a donor and (6)-1-(3-(methoxycarbonyl)- {5}-1-phenyl[5,6]-fullerene (PCBM)-as an acceptor in different weight ratios is applied to fabricate the polymer solar cell devices. The ratio of polymer/PCBM affects the solar cell efficiency and the best performance exhibits in the device with polymer/PCBM = 1:3 (w/w), which shows a power conversion efficiency (PCE) of 0.199% and a $V_{oc}$ of 0.99 V, respectively. Even though the device shows the very low PCE, the $V_{oc}$ is higher than that of well known bulk heterojunction type solar cell based on P3HT:PC61BM (c.a. 0.5 V).

• Journal of Chest Surgery
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• 제29권11호
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• pp.1241-1247
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• 1996

From January 1989 to March 1996, we have operated on 102 cases of non-small cell lung cancer at the department of Thoracic and Cardiovascular Surgery, Yonsei University Wonju College of Medicine. They were clinically evaluated. The results are as follows; 1. The peak incidence of age of primary lung cancer was 5th decade(34.3%) and 6th decade(38.2%). Male to female ratio was 2.5:1. 2. Most of symptoms were respiratory, which were cough(61.8%), sputum(43.l%), chest discomfort and pain(30.4%), dyspnea(27.5%), and hemoptysis(9.8%). Asymptomatic cases were 1.9% of study group. 3. Methods of diagnostic confirmation were bronchoscopic biopsy(59.8%), sputum cytology(17.6%), percutaneous needle aspiration(11.8%) and open biopsy(10.8%). 4. Histopathologic classifications were squamous cell carcinoma(55.9%), adenocarcinoma(30.5%), adenosquamous cell carcinoma(6.9%), large cell carcinoma(4.9%), bronchioalveolar cell carcinoma(0.9%), and mixed cell carcinoma(0.9%). 5. Methods of operation were pneumonectony(47.1%), lobectomy(38.2%), bilobectomy(5.9%), wedge resection(1.9%), exploration(6.9%), and overall resectability was 93.1%. 6. Postoperative staging classifications were Stage I (13.7%), Stage II(31.4%), Stage IIIa(38.3%), Stage IIIb(14.7%), and Stage IV(1.9%). 7. The postoperative complications developed in 9.8%, and operative mortality was 1.9 %. 8. One year survival rate was 81.7%, 3 year 49.7% and 5 year 21.8%. According to stage, 5 year survival rate was 39% in stage I, 24.3% in stage II, 23.9% in stage IIIa.

• Journal of Chest Surgery
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• 제47권3호
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• pp.255-261
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• 2014

Background: To determine the predictors of clinical outcomes following surgical descending thoracic aortic (DTA) repair. Methods: We identified 103 patients (23 females; mean age, $64.1{\pm}12.3$ years) who underwent DTA replacement from 1999 to 2011 using either deep hypothermic circulatory arrest (44%) or partial cardiopulmonary bypass (CPB, 56%). Results: The early mortality rate was 4.9% (n=5). Early major complications occurred in 21 patients (20.3%), which included newly required hemodialysis (9.7%), low cardiac output syndrome (6.8%), pneumonia (7.8%), stroke (6.8%), and multi-organ failure (3.9%). None experienced paraplegia. During a median follow-up of 56.3 months (inter-quartile range, 23.1 to 85.1 months), there were 17 late deaths and one aortic reoperation. Overall survival at 5 and 10 years was $80.9%{\pm}4.3%$ and $71.7%{\pm}5.9%$, respectively. Reoperation-free survival at 5 and 10 years was $77.3%{\pm}4.8%$ and $70.2%{\pm}5.8%$. Multivariable analysis revealed that age (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.05 to 1.15; p<0.001) and left ventricle (LV) function (HR, 0.88; 95% CI, 0.82 to 0.96; p<0.003) were significant and independent predictors of long-term mortality. CPB strategy, however, was not significantly related to mortality (p=0.49). Conclusion: Surgical DTA repair was practicable in terms of acceptable perioperative mortality/morbidity as well as favorable long-term survival. Age and LV function were risk factors for long-term mortality, irrespective of the CPB strategy.

• The Journal of the Korea Contents Association
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• 제9권6호
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• pp.289-299
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• 2009

This study set out to analyze the perceptions of investigative police officers and division police officers regarding Police Investigation Specialization, which had been in effect for four years, identify the problems, and search for alternative policies. The results led to the following alternative policies; first, the communication among the members should be facilitated by trading the jobs between investigative policemen and division members in certain percentage regularly, integrating job education and special work, and developing diverse support programs for detective activities to provide them with opportunities to experience and understand investigation. The second suggestion concerns the investigation members' morale. There should be a range of measures to boost their moral such as allocating separate budget and personnel to support the investigation department and the treatment of major criminal and civil cases, giving each investigation team an office and investigation room to improve their working environment, readjusting the promotion ratio of Police Investigation Specialization to introduce a promotion system proper for each investigation's characteristics. The third suggestion is to secure job efficiency. It's required to reinforce the current short-term specialized education program to bring up practical and professional investigators, open the certification exam of professional investigators to all members so that every policeman can have their abilities recognized and approved as long as they have the demanded capabilities, and create a system of shedding off the members idle at work by reflecting low performance records when evaluating the members to decide who to dismiss from Police Investigation Specialization. And finally, it's important to divide duties rationally. The rationality of duties division can be guaranteed by setting the guidelines for direct handling for the team leader to help him devote himself to his duties, defining objective criteria of measuring investigation workload, and creating devoted systems and teams for simple and small accidents so that experienced investigators can deal with high-profile cases.

• Korean Journal of Remote Sensing
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• 제16권3호
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• pp.243-260
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• 2000

Ocean remote sensing reflectance of just above water level was modeled using inherent optical properties of seawater contents, total absorption (a) and backscattering(bb) coefficients ($R_{rs}$=0.046 $b_b$/(a+$b_b$). This modeling was based on the specific absorption and backscattering coefficients of 5 optically active seawater components； phytoplankton pigments, non-chlorophyllous suspended particles, dissolved organic matters, heterotrophic microorganisms, and the other unknown particle components. Simulated remote sensing reflectance($R_{rs}$) and water leaving radiance(Lw) spectra were well agreed with in-situ measurements obtained using a bi-directional fields remote spectrometer in coastal waters and open ocean. $R_{rs}$ values in SeaWiFS bands from the model were analyzed to develop 2-band ratio ocean color chlorophyll with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The model algorithms were examined and compared with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The remote reflectance model will be very helpful to understand the variation of water leaving radiances caused by the various components in the seawater, and to develop new ocean color algorithm for CASE-II water using neural network method or other analytical method, and in the model of fine atmospheric signal correction.