• Membrane and Water Treatment
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• v.6 no.5
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• pp.423-437
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• 2015

Polyvinylidene fluoride/fullerene nanoparticle (PVDF/$C_{60}$) composite microfiltration (MF) membranes were fabricated by a non-solvent induced phase separation (NIPS) using N, N-dimethylacetamide (DMAc) as solvent and deionized water (DI) as coagulation solution. Polyvinylpyrrolidone (PVP) was added to the casting solution to form membrane pores. $C_{60}$ was added in increments of 0.2% from 0.0% to 1.0% to produce six different membrane types: one pristine PVDF membrane type with no $C_{60}$ added as control, and five composite membrane types with varying $C_{60}$ concentrations of 0.2, 0.4, 0.6, 0.8 and 1.0%, respectively. The mechanical strength, morphology, pore size and distribution, hydrophilicity, surface property, permeation performance, and fouling resistance of the six membranes types were characterized using respective analytical methods. The results indicate that membranes containing $C_{60}$ have higher surface porosity and pore density than the pristine membrane. The presence of numerous pores on the membrane caused weaker mechanical strength, but the water flux of the composite membranes increased in spite of their smaller size. Initial flux and surface roughness reached the maximum point among the composite membranes when the $C_{60}$ concentration was 0.6 wt.%.

• Membrane and Water Treatment
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• v.11 no.4
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• pp.257-274
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• 2020

There are many previous review articles are available to summarize either the characterization methods of effluent organic matter (EfOM) or the individual control treatment options. However, there has been no attempt made to compare in parallel the physicochemical treatment options that target the removal of EfOM from biological treatments. This review deals with the recent progress on the characterization of EfOM and the novel technologies developed for EfOM treatment. Based on the publications after 2010, the advantages and the limitations of several popularly used analytical tools are discussed for EfOM characterization, which include UV-visible and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC), and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). It is a recent trend to combine an SEC system with various types of detectors, because it can successfully track the chemical/functional composition of EfOM, which varies across a continuum of different molecular sizes. FT-ICR-MS is the most powerful tool to detect EfOM at molecular levels. However, it is noted that this method has rarely been utilized to understand the changes of EfOM in pre-treatment or post-treatment systems. Although membrane filtration is still the preferred method to treat EfOM before its discharge due to its high separation selectivity, the minimum requirements for additional chemicals, the ease of scaling up, and the continuous operation, recent advances in ion exchange and advanced oxidation processes are greatly noteworthy. Recent progress in the non-membrane technologies, which are based on novel materials, are expected to enhance the removal efficiency of EfOM and even make it feasible to selectively remove undesirable fractions/compounds from bulk EfOM.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.74-78
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• 1992

This paper describes an intelligent system to automatic evaluation of eddy current(EC) signal for Inspection of steam generator(SG) tubes in nuclear power plant. Some features of the intelligent system design in the proposed system are : (1) separation of representation scheme ,or event capturing knowledge in EC signal and for structural inspection knowledge in SG tubes inspection; (2) each representation scheme is implemented in different methods, one is syntactic pattern grammar and the other is rule based production. This intelligent system also includes an data base system and an user interface system to support integration of the hybrid knowledge processing methods. The intelligent system based on the proposed concept is useful in simplifying the knowledge elicitation process of the rule based production system, and in increasing the performance in real time signal inspection application.

• Journal of Ginseng Research
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• v.11 no.1
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• pp.10-16
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• 1987

This study was carried out to get basic information that can be used in quality control for processing ginseng products and also in separation of pure ginsenosides for experimental purpose. The composition of various parts of 6 year-old ginseng was 4.1% of rhizome (node), 47.7% of main root, 34.1% of lateral root and 14.1% of fine Toot on dried weight basis. The weight ratios of epidermis-cortex and xylem were about 1 : 1 in main root and about 2 : 1 in lateral root. The distribution of total saponin content shows 29.2% in main root, 34.6% in lateral root, 29.1% in fine root and 7% in rhizome, but the order of the content per unit weight was fine root > rhizome > lateral root > main root. Total saponin content according to age of root was increased gradually within 3% for 6 years, as compared with two year old root. In view of the increase of root weight owing to the net amount of saponin in root increased continuously. The increase rates of total saponins per year were 3.1,12.3,19.8,43.8 and 21.1% in 2, 3, 4, 5 and 6 years-old ginseng root, respectively.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.303-308
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• 1995

When we prepared the cooked namul, bugak and kimchi by the leaves of Cedrela sinensis, the changes of quercitrin which was isolated from the leaves of this plant in each preparations were analysed by HPLC. Separation by reversed phase chromatography on u-Bondapak C/Sub 18/ column was achieved by isocratic elution with THF-dioxane-MeOH-HOAc-5％ H/Sub 3/PO/Sub 4/-H/Sub 2/O (145: 125:50:20:2:658). When Kimchi was stored at 5$^{\circ}C$ for 20 days, the content of quercitrin in the methanol extract of Kimchi was 7.21％ and Kimchi at 20$^{\circ}C$ was reduced by 5.78％ (w/w). Contents of quercitrin in the leaves of Cedrela sinensis kimchi obsered to be gradually decreased during storage at 5$^{\circ}C$ and 20$^{\circ}C$. Contents of quercitrin of stored kimchi at 5$^{\circ}C$ was higher than that stored at 20$^{\circ}C$. The contents of quercitrin in Namul and Bugak were 13.06 and 5.03％ (w/w), respectively, which were lower than control.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.413-421
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• 2012

Purpose: The purpose of this study is to investigate the improvement measure of dental technician practical examination. Methods: A survey was performed on 111 dental technicians who were self-written questionnaire. The results were analyzed by SPSS 12.0. The collected data was analyzed by frequency and chi-square test. Results: Questions most necessary work tools with the articulator was the highest with 55.9%, Electric wax carver(16.2%), heating clear(14.4%), CAD/CAM program(9.0%) was in the order. The need for additional practical test in response to actions included maxillary and mandibular comments occlusal work that you have to wax up the highest rate of 63.8%. Items most in need of improvement was strengthen of clinically oriented(48.0%), separation of written and practical(14.6%), control the degree of difficulty(11.4%) were the next order. Conclusion: Based on the results of this study, the current dental technician did not show major problems in the practical test. However, clinicians should be strengthened mainly. To do this, the use of the articulator is essential.

• Geomechanics and Engineering
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• v.20 no.6
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• pp.485-495
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• 2020

Based on the movement characteristics of overlying strata with gangue backfilling, the compression test of gangue is designed. The deformation characterristics of gangue is obtained based on the different Talbot index. The deformation has a logarithmic growth trend, including sharp deformation stage, linear deformation stage, rheological stage, and the resistance to deformation changes in different stages. The more advantageous Talbot gradation index is obtained to control the surface subsidence. On the basis of similarity simulation test with gangue backfilling, the characteristics of roof failure and the evolution of the supporting force are analyzed. In the early stage of gangue backfilling, beam structure damage directly occurs at the roof, and the layer is separated from the overlying rock. As the working face advances, the crack arch of the basic roof is generated, and the separation layer is closed. Due to the supporting effect of filling gangue, the stress concentration in gangue backfilling stope is relatively mild. Based on the equivalent mining height model of gangue backfilling stope, the relationship between full ratio and mining height is obtained. It is necessary to ensure that the gradation of filling gangue meets the Talbot distribution of n=0.5, and the full ratio meets the protection grade requirements of surface buildings.

• Herbal Formula Science
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• v.20 no.2
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• pp.37-46
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• 2012

Objectives : Oyaksungi-san(Wuyaoshunqisan) has been used for treatment of stroke and rheumatoid arthritis in Korea. In this study, a simple and accurate high-performance liquid chromatography(HPLC) method was established for simultaneous determination of six main components, liquiritin, ferulic acid, naringin, hesperidin, neohesperidin, and glycyrrhizin in Oyaksungi-san, a traditional Korean herbal prescription. Methods : The analytical column for separation of six constituents was used a Gemini $C_{18}$ column maintained at $40^{\circ}C$. The mobile phase consisted of two solvent systems, 1.0% (v/v) acetic acid in $H_2O$ (A) and 1.0% (v/v) acetic acid in acetonitrile (B) by gradient flow. The flow rate was 1.0 mL/min and the detector was a photodiode array (PDA) set at 254 nm for glycyrrhizin, 280 nm for liquiritin, naringin, hesperidin, and neohesperidin, and 320 nm for ferulic acid. Results : Calibration curves were acquired with $r^2$ values ${\geq}0.9998$. The results of recovery test were 91.58%-105.90% with a relative standard deviations (RSDs, %) value less than 2.0%. The values of RSD for intra- and inter-day precision were 0.03%-1.72% and 0.03%-1.63%, respectively. The contents of the six compounds in Oyaksungi-san were 0.33-9.30 mg/g. Conclusions : The newly established HPLC method will be helpful to improve quality control of Oyaksungi-san.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.423-431
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• 2002

An experimental study is conducted to investigate the effect of two-frequency forcing on turbulent flow behind a backward-facing step at the Reynolds number of 27000 based on the step height. The forcing is provided from a thin slit located at the edge of the backward-facing step to increase mixing behind the backward-facing step and consequently to reduce the reattachment length. With single frequency forcing, the minimum reattachment length is obtained at the non-dimensional forcing frequency (F) of St$\_$h/ = 0.29. With two-frequency forcing, a subharmonic frequency (F/2) or biharmonic frequency (2F) is combined with the fundamental frequency (F), i.e. (F, F/2) or (F, 2F) forcing is applied. In the case of (F, F/2) forcing, the reattachment length is not much sensitive to the phase difference between F and F/2. However, the reattachment length significantly depends on the phase difference between F and 2F in the case of (F, 2F) forcing. At a certain range of the phase difference, the reattachment length becomes smaller than that of the single frequency forcing.