• Membrane Journal
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• v.28 no.3
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• pp.157-168
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• 2018

Potassium tannate (TA-K), which is prepared by base treatment of the bio-renewable tannic acid (TA), was evaluated for its potential application as a draw solute for water purification by forward osmosis. The forward osmosis and recovery properties of TA-K were systematically investigated. In the application of forward osmosis through the active layer facing feed solution (AL-FS) method, the water flux of TA-K draw solution was significantly higher than that of the TA draw solution, while that of the latter was not identified. At a low concentration of 100 mM, the osmotic pressure (1,135 mOsmol/kg) of the TA-K draw solution was approximately 6.5 times that (173 mOsmol/kg) of the NaCl draw solution. Furthermore, the water flux and specific salt flux (6.14 LMH, 1.26 g/L) of the TA-K draw solution at 100 mM were approximately 2.5 and 0.5 times those of the NaCl draw solution (2.46 LMH, 2.63 g/L) at the same concentration, respectively. For reuse, TA-K was precipitated by using a metal ion and recovered through membrane filtration. This study demonstrates the applicability of a phytochemical material as a draw solute for forward osmosis.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.1
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• pp.23-41
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• 1999

During the previous several decades the osseointegrated implants have been considered as the most ideal therapy for the fully edentulous or partially edentulous patients. Although the research on the biocompatibility of osseointegration, the oral tactile function, and the histo-neurologic study had been performed, the change of the oral tactile sensibility and maximal occlusal force according to the postinsertion time of implant prostheses has not been studied. The purpose of this study was to compare the oral tactile sensibility and maximal occlusal force of implant pros-theses to natural teeth according to the specific postinsertion time intervals. The fifty seven patients treated with $Br{\aa}nemark$ implants during the recent seven years were involved in this study. The oral tactile sensibility and maximal occlusal force were measured according to the postinsertion time (${\leqq}6\;months,\;{\leqq}12\;{\leqq}\;18\;months\;{\leqq}\;24\;months,\;and\;{\geqq}20\;months$) 1. The passive tactile threshold of implants was higher than 6-7 times when comparing to natural teeth(P<0.05) 2. The absolute pressure threshold in horizontal and vertical direction for the passive tactile sensibility had decreased significantly in the post insertion time 13-18 months group and had increased significantly in the post insertion time over 25 months group (P<0.05) 3. 50% limit thickness and 100% absolute thickness for the active tactile sensibility had decreased significantly in the postinsertion time 7-12 months group ($AT_{50}:P<0.005,\;AT_{100}:P<0.05$) 4. The maximal occlusal force of the implants prostheses had decreased when comparing with natural teeth in the postinsertion time 1-6 months group(P<0.05) and after that there was no significant difference between the implant prostheses and natural teeth(P<0.05) 5. Maximal occlusal force according to the postinsertion time had increased significantly in the 13-18 months group (P<0.05) after that there was no significant difference. 6. There was positive correlation between age and oral tactile sensibility tested in horizontal and vertical direction ($P_{H:r}=0.39,\;P_{v:r}=0.41$) and there was no correlation between age and maximal occlusal force, age and active tactile sensibility 7. According to the results or the questionnaire, 76.6% of the patients were satisfied with the function and 96.7% of the patients were satisfied with the sensibility. In conclusion oral tactile sensibility and maximal occlusal force of implants have changed with the postinsertion time. Oral tactile function of implants was lower than that of the natural teeth, but for the maximal occlusal force there was no difference between implants and natural teeth.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.2 s.51
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• pp.141-146
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• 2005

Unstable cosmetic active ingredients could rapidly break down in chemical and photochemical process. Therefore, it has become a very important issue to encapsulate active ingredient for the stabilization. 7-Dehydrocholesterol (7-DHC), a precursor of vitamin $D_3$, has been shown to increase levels of protein and mRNA for heat shock protein in normal human epidermal keratinocytes. However, topical dermal application of 7-DHC is restricted due to its poor solubility and chemical unstability. In this study, 7-DHC was incorporated into nano-emulsion (NE), solid lipid nano-particle (SLN), and chitosan coated solid lipid nano-particle (CASLN), respectively. In order to prepare NE and SLN dispersion, high-pressure homogenization at temperature above the melting point of lipid was used Hydrogenated lecithin and polysorbate 60 were used as stabilizer for NE and SLN. CASLN was prepared by high speed homogenizing after adding chitosan solution to the SLN dispersion and showed positively charged particle properties. Decomposition rate of 7-DHC in NE, SLN and CASLN was studied as a function of time at different temperature. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies were performed to characterize state of lipid modification. It appeared that CASLN is the most effective to stabilize 7-DHC and may be used for a useful topical dermal delivery system.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.156-163
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• 2015

In this paper, we propose an active water level and distance measurement algorithm using a light beam pattern. On behalf of conventional water level gauge types of pressure, float-well, ultrasonic, radar, and others, recently, extensive research for video analysis based water level measurement methods is gradually increasing as an importance of accurate measurement, monitoring convenience, and much more has been emphasized. By turning a reference light beam pattern on bridge or embankment actively, we suggest a new approach that analyzes and processes the projected light beam pattern image obtained from camera device, measures automatically water level and distance between a camera and a bridge or a levee. As contrasted with conventional methods that passively have to analyze captured video information for recognition of a watermark attached on a bridge or specific marker, we actively use the reference light beam pattern suited to the installed bridge environment. So, our method offers a robust water level measurement. The reasons are as follows. At first, our algorithm is effective against unfavorable visual field, pollution or damage of watermark, and so on, and in the next, this is possible to monitor in real-time the portable-based local situation by day and night. Furthermore, our method is not need additional floodlight. Tests are simulated under indoor environment conditions from distance measurement over 0.4-1.4m and height measurement over 13.5-32.5cm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.789-799
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• 2019

The settlement hardly occurs in structures supported by pile foundation such as abutment, culvert but a cavity is formed in the lower part of a structure. As a result, soil discharged from the lateral ground to the cavity accelerates the settlement of the lateral ground of the structure, resulting in a larger settlement. Therefore, in order to prevent problems caused by cavity under the structure supported by pile foundation, soil Flow Protector (briefly called 'FLP'), which can be easily installed on the side of structure, was developed. In this study, an laboratory model test was carried out to prove the reduction effect of settlement and to estimate the optimal installation length of the FLP. As a result, the installation of the FLP reduced the settlement of the lateral ground and prevented the leakage of lateral ground soil into the cavity. If the stiffness of the FLP is small, the state or active earth pressure is generated in the upper part, which is not favorable for stability. But if the stiffness of the FLP is high enough, the passive earth pressure area is generated in the upper part, which will be advantageous for the stability. Also, the increased installation length of FLP is effective to reduce the settlement. And the ratio of the optimal length of the FLP to the box structure height (H = 250 mm) are flexible FLP 1.38, stiff FLP 0.73.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.25-32
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• 2013

This study has been conducted in order to propose Eco-friendly and High functional waterproofing technology available for structure by verifying application and performance of water proofing material(s) in purpose of making effective use of reclaimed rubber. As s result of 12 months evaluation, stable performance for water pressure and lateral pressure of $0.3N/mm^2$ were confirmed. Also, as the time elapsed, the amount of water absorption and adhesion performance showed only a slight difference(+0.05g, $-0.1Nmm^2$) as well, which in turn confirmed that waterproofing performance remains stable. Studies show that it is expected to expand recycling technology of natural rubber by applying reclaimed rubber on construction waterproofing field, and to hold a technical superiority by using eco-friendly material in construction waterproofing market throughout active application of these types of research.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.195-201
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• 2013

In atherosclerosis, blood vessels become sensitive to vessel-constricting agents leading to reduced control in the event of abrupt blood pressure changes. Mulberry trees (Morus alba L., MA) have been claimed to contain various bioactive principles that could possibly prevent atherosclerosis development caused by high cholesterol consumption. In order to examine whether MA feeding can prevent the sensitization of blood vessels, MA leaves were fed to rats for 8 weeks and pressor responses to vasoconstricting agents were assessed. Animals were pithed before blood pressure assessments to eliminate reflex compensation in vessel responses. Feeding diets containing high levels of cholesterol led to potentiated pressor responses to sympathetic nerve stimulation, or to injection of norepinephrine, phenylephrine, angiotensin II and vasopressin in pithed rats. These potentiated pressor responses were prevented in rats fed MA leaf-containing diets at 2 or 10% levels. It was also examined in anesthetized non-pithed rats whether similar cholestrol-related sensitization and MA prevention could be observed. However, high cholesterol-induced sensitization in pressor responses were not observed, suggesting that destruction of central cardiovascular control by pithing must have revealed the sensitization responses. It was concluded that MA leaves seem to be active in preventing abnormal blood vessel reactivity caused by hypercholesterolemia.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.269-281
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• 2017

Recently, the need for research into environmental and intrapsychic variables to promote active career preparation behavior is increasing, due to the increasing need to cultivate career preparation behavior starting from middle school. On the basis of this need, the purpose of this study is to identify the mediating effects of hope in the relationship between maternal learning involvement and career preparation behavior among middle school students. We surveyed 320 middle school students in W city, Gangwon-do, regarding these variables. We evaluated the results according to Baron and Kenny's (1986) mediating effect test procedure. The findings showed a significant positive correlation between positive maternal learning involvement, such as respecting their children's learning methods and providing academic information and advice, and the students' career preparation behavior and hope. However, the findings didn't show any significant correlation between negative maternal learning involvement, such as pressure for academic performance, and the students' career preparation and hope. Furthermore, hope was found to partially mediate the relationship between maternal positive learning involvement, including academic information and advice, and career preparation behavior, while fully mediating the relationship between career preparation behavior and respecting the students' learning methods. However, it did not have any mediating effect on the relationship between pressure for academic performance and career preparation behavior. These results highlight the important role that instilling hope in students, through respecting their learning methods and advising and providing the necessary academic information, plays in achieving a higher level of career preparation behavior.

• Clean Technology
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• v.20 no.3
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• pp.212-217
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• 2014

In order to regenerate the sulfidated desulfurization sorbent, oxygen is used as the oxidant agent on the regeneration process. The small amount of oxygen un-reacted in regeneration process is flowed into direct sulfur recovery process. However, the reactivity for $SO_2$ reduction can be deteriorated with the un-reacted oxygen by various reasons. In this study, the deactivation effects of un-reacted oxygen contained in the off-gas of regeneration process flowed into direct sulfur recovery process of hot gas desulfurization system were investigated. Sn-Zr based catalysts were used as the catalyst for $SO_2$ reduction. The contents of $SO_2$ and $O_2$ contained in the regenerator off-gas used as the reactants were fixed to 5.0 vol% and 4.0 vol%, respectively. The catalytic activity tests with a Sn-Zr based catalyst were for $SO_2$ reduction performed at $300-450^{\circ}C$ and 1-20 atm. The un-reacted oxygen oxidized the elemental sulfur produced by $SO_2$ catalytic reduction and the conversion of $SO_2$ was reduced due to the production of $SO_2$. However, the temperature for the oxidation of elemental sulfur increased with increasing pressure in the catalytic reactor. Therefore, it was concluded that the decrease of reactivity at high pressure is occurred by catalytic deactivation, which is the re-oxidation of lattice oxygen vacancy in Sn-Zr based catalyst with the un-reacted oxygen on the catalysis by redox mechanism. Meanwhile the un-reacted oxygen oxidized CO supplied as the reducing agent and the temperature in the catalyst packed bed also increased due to the combustion of CO. It was concluded that the rapidly increasing temperature in the packed bed can induce the catalytic deactivation such as the sintering of active components.

• The Journal of the Acoustical Society of Korea
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• v.15 no.2
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• pp.21-32
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• 1996

The performance of the energy density control algorithm for controlling a broadband noise is evaluated in a one-dimensional enclosure. To avoid noncausality problem of a control filter, which often happens in a frequency domain optimization, analyses presented in this paper are undertaken in the time domain. This approach provides the form of the causally constrained optimal controller. Numerical results are presented to predict the performance of the active noise control system, and indicate that imp개ved global attenuation of the broadband noise can be achieved by minimizing the energy density, rather than the squared pressure. It is shown that minimizing the energy density at a single location yields global attenuation results that are comparable to minimizing the potential energy. Furthermore, unlike the squared pressure control, the energy density control does not demonstrate any dependence on the error sensor location for this one-dimensional field. A practical implementation of the energy-based control algorithm is presented. Results show that the energy density control can be implemented using the two sensor technique with a tolerable margin of performance degradation.