• Mass Spectrometry Letters
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• v.5 no.1
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• pp.30-33
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• 2014

A solid phase extraction (SPE) method was optimized for the quantitative analysis of perfluorooctanoic acid (PFOA) in serum using hydrophilic-lipophilic balance SPE and LC-MS/MS. Fetal bovine serums spiked with $^{13}C_8$-PFOA before or after SPE were used as test samples for evaluation of the SPE efficiency. Simultaneous evaluation of matrix effects and absolute SPE recovery for $^{13}C_8$-PFOA in serum using different sample pre-treatments and SPE conditions allowed optimization of SPE process efficiency with minimal matrix effect and decent SPE recovery. Introduction of protein precipitation as a sample pre-treatment procedure for serum samples before SPE generally decreased matrix effect in LC-MS/MS analysis and provided more stable recovery of PFOA.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.247-250
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• 1992

Effects of free alkali and moisture on sucrose polyesters (SPE)-possible non calorie fat substitute-synthesis were investigated using a model system composed of sodium oleate, sucrose, potassium carbonate and methyl oleate. Trace amounts of free alkali in sodium oleate were found to interefere with SPE synthesis. When free alkali content in sodium oleate was varied gradually from 0% to 5%(w/w), the yield of SPE production was reduced from 92% to 45.5%. The moisture absorbed in sodium oleate, sucrose and potassium carbonate during storage also interefered with SPE synthesis. The yield (92%) of SPE production with dried ($105^{\circ}C$.6 hrs) reactants and catalysts was higher than that (89%) of SPE production with non-dried. Soybean oil fatty acid sodium soaps (FASS) not containing free alkali could be manufactured with slightly less than molar ratio of sodium hydroxide to soybean oil fatty acid methyl esters (FAME). Practically, 91.7% yield of soybean oil SPE production was outcomed by minimizing free alkali and moisture which were remaining in sucrose, potassium carbonate, soybean oil FASS and soybean oil FAME.

• Food Science of Animal Resources
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• v.35 no.2
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• pp.164-170
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• 2015

The objective of this study was to evaluated the photoprotective effects of porcine placenta extract (PPE) on ultraviolet B (UVB)-induced oxidative stress in human keratinocytes (HaCaT) to evaluate its functional activities as a skin food ingredient. PPE prepared by subcritical water extraction was termed SPE, and subsequently digested by enzymes to prepare E-SPE. Increased intracellular reactive oxygen species (ROS) levels (192.0%) induced by UVB were decreased by SPE and E-SPE. SPE had more effective ROS scavenging activity than E-SPE treatment. UVB treatment increased expression of tissue inhibitor of metalloproteinase 1 (TIMP-1), and this elevated expression was decreased by E-SPE treatment. High-dose treatment with E-SPE (50 and 100 µg/mL) reduced TIMP-1 expression levels of UVB-C (control) to 33.5 and 34.6%, respectively. In contrast, at low SPE doses (1 and 10 µg/mL), the treatment slightly decreased TIMP- 1 expression levels to 73.3% and 71.3% of UVB-C, respectively. In conclusion, the present study demonstrated the protective effect of SPE and E-SPE against UVB damage in keratinocytes via ROS scavenging, down-regulating MMP-2 expression and up-regulating TIMP- 1 expression. This highlights the potential for SPE as an ingredient in the preparation of functional food against photoaging.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.117-120
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• 2006

In this paper an integrated model of PV-AF (Photovoltaic-Active Filter) and PV-SPE(Photovoltaic Solid Polymer Electrolyte) system using PSCAD/EMTDC were explained in detaiil. The main concept of PV-AF system starts from the 'harmonics'. In order to deliver power to utility, PV system essentially needs a converter system. Here PV-AF system adds the function of active filter to the converter system installed in PV system, which was introduced already in several papers. PV-SPE system has been studied as a replacement of existing hydrogen production technology that emits large amount of carbon dioxide into atmosphere. Until now, these two systems, PV-AF and PV-SPE, have been considered separately However, in this paper, characteristics and advantages of combined system are discussed in detail.

• Journal of Astronomy and Space Sciences
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• v.26 no.4
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• pp.479-486
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• 2009

We studied the solar proton events (SPEs) associated with coronal mass ejections (CMEs) during the solar cycle 23 (1997-2006). Using 63 SPE dataset, we investigated the relationship among SPE, flare, and CME, and found that (1) SPE rise time and duration time depend on CME speed and the earthward direction parameter of the CME, and (2) the SPE peak intensity depends on CME speed and X-ray Flare intensity. While inspecting the relation between SPE peak intensity and the direction parameter, we found there are two groups: first group consists of large six SPEs (> 10,000 pfu at > 10 MeV proton channel of GOES satellite) and shows strong correlation (cc = 0.65) between SPE peak intensity and CME direction parameter. The second group has a weak intensity and shows poor correlation between SPE peak intensity and the direction parameter (cc = 0.01). By investigating characteristics of the first group, we found that all the SPEs are associated with very fast halo CME (> 1400km/s) and also they are mostly located at central region and within ${\pm}20^{\circ}$ latitude and ${\pm}30^{\circ}$ longitude strip.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.57-65
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• 2013

The development of the oil refining industry has resulted in an annual 120 million tons of sulphur, which is a by-product of the desulphurization process. To exploit this abundance, the applications of sulphur must be expanded. as excellent durability of reuse of leftover sulphur which has high potential for utilization in construction materials, the study is actively in progress. Meanwhile, there has been active research on semi-rigid pavements that draw on the strengths and overcome the weaknesses of asphalt and concrete pavements. Acrylate is used to prevent cracking but involves a high cost, thus, an alternative material is required. As such, this study presents methods on the reuse of leftover sulphur and examines the engineering performance of grout containing sulfur polymer emulsion (SPE) for use in semi-rigid pavements. Our analysis shows that grout in which 30% of acrylate is replaced with SPE has superior properties in terms of time of flow and strength compared to regular grout. However, performance declined when more than 50% of acrylate was replaced by SPE, indicating that the optimum replacement level is 30%. Through SEM analysis, we found that grout with utra harding cement in this study at three hours had similar hydration properties to that of Type 1 Ordinary Portland Cement (OPC) at seven days, and maintained the properties regardless of grout containing SPE. OPC and grout with a replacement level of 30% displayed similar levels of chloride invasion resistance, whereas grout without SPE was far less resistant. Within the scope of this paper, the optimum replacement level of acrylate with SPE was found to be 30% in consideration of various properties such as time of flow, strength, and chloride invasion resistance.

• Proceedings of the KIEE Conference
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• summer
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• pp.1495-1497
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• 2004

This paper presents an effective modeling scheme of SPE cell system for hydrogen production. As oxygen and hydrogen produced by water electrolysis using SPE are high purity, we can use oxygen in biomedical and hydrogen could be used in many ways. Recently, it is under the eye as a surplus power storage system. PSCAD/EMTDC model of SPE cell system for hydrogen production to efficiently utilize Solar cell energy which produces effectively hydrogen energy is showed in this paper. The simulated results are then verified by comparing them with the actual values obtained from the data acquisition system. Authors are sure that it is a useful method to the researchers who study SPE cell system for hydrogen production.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.250-252
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• 2005

This paper presents an newly developed MPPT method for PV-SPE system. To chase maximum power point at every moment under conventional MPPT control method, voltage and current coming out from PV-cell are needed to be feedbacked. In this newly developed Maximum Current Control method, however, current flowing into SPE cell is only one considerable factor. To verify the theory, simulated results are compared and shown in this paper. Authors are sure that it is the most useful method to the maximum power from PV to SPE with only a feedback of SPE input current.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.663-669
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• 1999

For determination of separated pesticides by using GC and HPLC, liquid-liquid extraction(LLE) and solid phase extraction(SPE) have been carried out to separate and concentrate the organophophorous pesticides such as Diazinon, Fenitrothion, Phosmet, Phosalon and EPN in environmental water samples. ln determination of pesticides by HPLC/UV, SPE has resulted in higher recovery and more precision than LLE, while in determination of pesticides by GC/FPD, vice versa. HPLC/UV after the pretreatment process of sample by solid phase extraction (SPE-HPLC/UV) has suggested the possibility of determination of pesticides ppb level. ln comparison of detection limit, both SPE-HPLC/UV and LLE-GC/FPD are reasonably suitable for analysis of residue pesticides. ln the respect of the rapidity and the solvent required, SPE-HPLC/UV method has proven to be superior to LLE-GC/FPD.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.33.2-33.2
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• 2010

We have investigated a relationship among the solar proton events (SPEs), coronal mass ejections (CMEs) and solar flares during the solar cycle 23 (1997-2006). Using 63 SPE dataset, we found that SPE rise time, duration time, and decrease times depend on CME speed and SPE peak intensity depends on the CME earthward direction parameter as well as CME speed and x-ray flare intensity. While inspecting the relation between SPE peak intensity and the CME earthward direction parameter, we found that there are two groups: first group consists of large 6 SPEs (> 10,000 pfu at >10 MeV proton channel of GOES satellite) and shows a very good correlation (cc=0.65) between SPE peak intensity and CME earthward direction parameter. The second group has a relatively weak SPE peak intensity and shows poor correlation between SPE peak intensity and the CME earthward direction parameter (cc=0.01). By investigating characteristics of 6 SPEs in the first group, we found that there are special common conditions of the extremely large proton events (group 1); (1) all the SPEs are associated with very fast halo CME (>1400km/s), (2) they are almost located at disk region, (3) they also accompany large flare (>M7), (4) all they are preceded by another wide CMEs, and (5) they all show helmet streamer nearby the main CME. In this presentation, we will give details of the energy spectra of the 6 SPE events from the ERNE/HED aboard the Solar and Heliospheric Observatory (SOHO), and onset time comparison among the SPE, flare, type II burst, and CME.