• The Journal of the Acoustical Society of Korea
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• v.7 no.2
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• pp.20-25
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• 1988

This study is to explain the characteristic of excess attenuation on the ground through the outdoors experiment about noise propagation and the reduced model experiment of acoustic. The outdoors experiment on the attenuation of noise propagation was tried with the small engine that had large acoustic output, and then it was conformed that there was relationship between the excess attenuation calculated by measurement from distance attenuation and Log(D/(Hs+Hr)). As a result, it was found that the attenuation of noise propogation depended upon the direction of the wind and frequency and was regressed in a straight line. And the numerical values of excess attenuation on the ground could be calculated by regarding Log(D/(Hs+Hr)) as a parameter with an airing resistance $\sigma$. It was found that when the mean square error between the excess attenuation calculated by measurement and the value calculated by a fomula $L=-20Log\mid1+(r_1/r_2)Qexp(ik, \bigtriangleup r)\mid$ about optional $\sigma$ was least, the optimal decision of u was made. As the characteristic of model is the model experiment on a reduced scale of 1 to 40, It was conformed that it corresponds enough with the measurement value with measuring the distance attenuation in the large anecoic chamber.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.701-710
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• 2019

Objective: This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure. Methods: Chickens were randomly divided into 7 groups to receive different HS treatments: i) $36^{\circ}C$ for 1 h, ii) $36^{\circ}C$ for 2 h, iii) $38^{\circ}C$ for 1 h, iv) $38^{\circ}C$ for 2 h, v) $40^{\circ}C$ for 1 h, vi) $40^{\circ}C$ for 2 h, and vii) un-stressed control group ($25^{\circ}C$). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed. Results: HS temperatures had significant effects on breast meat temperature, lightness ($L^*$), redness ($a^*$), cooking loss and protein solubility (p<0.05). The HS at $36^{\circ}C$ increased $L^*{_{24h}}$ value (p<0.01) and increased the cooking loss (p<0.05), but decreased $a^*{_{24h}}$ value (p<0.05). However, as the temperature increased to $38^{\circ}C$ and $40^{\circ}C$, all the values of $L^*{_{24h}}$, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p>0.05). Only the ultimate $pH_{24h}$ at $40^{\circ}C$ decreased compared to the control group (p<0.01). The pH in $36^{\circ}C$ group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group $40^{\circ}C$ was much better than those in $36^{\circ}C$ with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection. Conclusion: HS at higher temperature (above $38^{\circ}C$) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from $36^{\circ}C$. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.

• Analytical Science and Technology
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• v.20 no.6
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• pp.488-495
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• 2007

A wallpaper having many surfaces in indoor is composed of various raw materials. In this study, TVOC contribution from raw materials of PVC wallpaper was evaluated by using headspace-solid phase microextraction (HS-SPME)-GC/MS. Samples were diluent, resin stabilizer, plasticizer, filler, blowing agent and PVC resin. 9 mL of each sample was put into 22 mL glass vial and they were equilibrated for 1 hour at $100^{\circ}C$. Headspace in vial was absorbed to $75{\mu}m$ Carboxen-PDMS fiber and analyzed by GC/MS. Aromatic compounds like a toluene, ethylbenzene and xylene, ketones compounds like a acetone, methoxyacetone and 2-butanone and alkane compounds like a nonane decane and undecane were identified from raw materials. And alcohol compounds like a ethanol and butanol and aldehydes were detected. TVOC emission of diluent, resin stabilizer, plasticizer, PVC resin, blowing agent and filler were $54.20{\mu}g/g$, $32.88{\mu}g/g$, $0.50{\mu}g/g$, $0.88{\mu}g/g$, $0.22{\mu}g/g$ and $0.11{\mu}g/g$, respectively. Contribution of TVOC emission of diluent, resin stabilizer and PVC resin that were concerned about add ratio were 0.708, 0.129, 0.115, respectively. In conclusion, it's necessary to reduce TVOC emission through improvement of diluent, resin stabilizer and PVC resin. Also, HS-SPME-GC/MS method which was developed in this study will be used for raw materials analysis effectively.

• Bulletin of the Korean Chemical Society
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• v.27 no.2
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

• Journal of Acupuncture Research
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• v.19 no.3
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• pp.41-50
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• 2002

Objective : To study anti-inflammatory, analgesic effect and molecular biological mechanism of honey bee venom for aqua-acupuncture, human mast cell line(HMC-1) and human glioma cell line(HS683) were treated with bee venom. Methods : Cell viability of bee venom was tested by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) asssay. To explore whether anti-inflammatory, analgesic effects of bee venom are associated with the control of gene expression, quantitative RT-PCR analysis of inflammation and pain related genes was performed. Results : The MTT assay demonstrated that cell viability was not decreased by treatment with 10-9 ug/ml bee venom in comparison with 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, 10-8, 10-9, 10-10 and 10-11 ug/ml. sPLA2 and COX-l were down-regulated by treatment with 10-9 ug/ml bee venom in HS683 Cell line in comparison with control. COX-2 was up-regulated by treatment with 10-9 ug/ml bee venom in HS683 Cell line and HSP-2 was up-regulated by treatment with 10-9 ug/ml bee venom in HMC-1 Cell line in comparison with control. sPLA2, COX-1 and COX-2 showed no significant regulation in HMC-1 Cell line and cPLA2 also showed no significant regulation in both HMC-l and HS683 Cell line between control and bee venom treated group.

• Mass Spectrometry Letters
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• v.8 no.1
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• pp.18-22
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• 2017

Products containing any one or more of 26 fragrance allergens likely to cause contact allergies, are required under the 2008 domestic cosmetic law to be labeled when their concentrations exceed a certain range. This study focuses on the comparison and development of analytical methods based on headspace-solid phase micro extraction (HS-SPME) and liquid-liquid extraction (LLE) methods followed by GC-MS/MS for 24 of the fragrance allergens excepting for two natural materials in water samples. Using the developed HS-SPME method, 15 of the 24 fragrance allergens were analyzed and 9 compounds which have relatively low $logK_{OW}$ values (below about 2.5) were not extracted, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9969 or more, and the method detection limits (MDL) and the limits of quantification (LOQ) were $0.078{\sim}0.582{\mu}g/L$ and $0.261{\sim}1.940{\mu}g/L$, respectively. In the case of using the optimized LLE method, all 24 fragrance allergens were analyzed, and the correlation coefficient ($r^2$) of the calibration curve for quantification showed linearity of 0.9957 or more, MDL and LOQ were $0.020{\sim}0.138{\mu}g/L$ and $0.065{\sim}0.440{\mu}g/L$, respectively.

• Journal of the Korean Wood Science and Technology
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• v.45 no.6
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• pp.682-688
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• 2017

Fresh japanese anise (Illicium anisatum L.) tree leaves were collected and ground after drying. The essential oils of the leaves were analyzed by gas chromatography-mass spectrometry (GC-MS) using headspace (HS) and solid phase-microextra (SPME) methods. Volatile components of the leaves were identified 21 and 65 components in HS and SPME, respectively. The main components of the essential oils obtained by HS method were eucalyptol (36.7%), (+)-sabinene (15.61%), ${\delta}$-3-carene (6.87%), ${\alpha}$-pinene (6.07%), ${\gamma}$-terpinen (5.72%), ${\alpha}$-limonene (5.26%), ${\beta}$-myrcene (4.13%), ${\alpha}$-terpinene (4.04%) and ${\beta}$-pinene (3.73%). The other components were less than 3.5%. SPME method also showed that eucalyptol (17.88%) was main. The other were 5-allyl-1-methoxy-2 (13.29%), caryophyllene (6.09%), (+)-sabinene (5.60%), ${\alpha}$-ocimene (4.89%) and ${\beta}$-myrcene (3.73%), and the rest were less amounts than 3.5%. This work indicated that many more volatile components were isolated, comparing to the previous literature data and that SPME method was much more effective than HS method in the analysis of the volatile components.

• Journal of Dairy Science and Biotechnology
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• v.37 no.2
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• pp.136-153
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• 2019

The present study aimed to investigate the effects of skin care foods on the synthesis of pro-collagen type I C peptide and suppression of matrix metalloproteinase (MMP)-1 secretion through an in vitro study using fibroblasts (Hs68 cells) and keratinocytes (HaCaT cells). Among the three skin care foods developed in this study, three beans cookie and avocado yoghurt influenced the production of pro-collagen type I C peptide and suppressed MMP-1 secretion; however, tiger nut Galsu drink did not exhibit these effects. All skin care foods, including three beans cookie and plain yoghurt ($50{\mu}g/mL$, p<0.001) influenced the suppression of MMP-1 in addition to other commercially available breast milk production support foods examined, such as Heath Heather ($50{\mu}g/mL$, p<0.001), Happy Mama ($50{\mu}g/mL$, p<0.01), BioLys ($50{\mu}g/mL$, p<0.001), Enfamama ($25{\mu}g/mL$, p<0.0001), and Pregnagen ($25{\mu}g/mL$, p<0.001). Avocado fruit yoghurt ($25{\mu}g/mL$, p<0.05), avocado fruit jam yoghurt ($50{\mu}g/mL$, p<0.01), Enfamama ($100{\mu}g/mL$, p<0.05), and Pregnagen ($100{\mu}g/mL$, p<0.05) influenced the production of pro-collagen type I C peptide and suppressed MMP-1 secretion. This result indicates that only avocado jam yoghurt significantly influenced both the prevention of skin keratinization and acceleration of recovery of skin fibrous structure. Therefore, avocado is a favorable ingredient for nutrition-balanced dietary foods or an essential ingredient in products for revitalization of human skin.

• Analytical Science and Technology
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• v.25 no.1
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• pp.39-49
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• 2012

A method to detect 37 volatile organic compounds (VOCs) in surface water was described based on headspace solid-phase micro extraction and gas chromatography-mass spectrometry. VOCs in water were vaporized for 30 min at 40 $^{\circ}C$ in a headspace vial and adsorbed on 85 ${\mu}m$ carboxen-polydimethylsiloxane. Under the established condition, the lowest quantification limit was 4.1-96 ng/L by using 4.0 mL water sample, and the relative standard deviation was less than 15% at concentrations of 0.05 and 0.50 ${\mu}g/L$. The detection limits meet lower concentration than 1/10 of the water quality criteria for VOCs established by the US EPA or Germany. The LOQ is a sensitivity which the monitoring for the establishing water quality criteria requires. When the proposed method was used to analyze the target compounds in sixteen surface water samples and total 16 VOCs were detected in surface water samples collected from Gum-River. Maximum concentrations of VOCs detected were not exceeded the EPA or Germany guidelines in any of the samples.

• Journal of the Optical Society of Korea
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• v.19 no.5
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• pp.449-455
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• 2015

In this study we propose a new photonic crystal fiber (PCF) design that simultaneously offers broadband single-mode operation, high birefringence, and large normal dispersion in the optical-communication wavelength regime. The waveguide is based on a hybrid square-lattice PCF (HS-PCF) that has circular air holes of two different diameters alternating in the cladding, plus a pure silica defect at the center. The optical properties of the guided modes are analyzed numerically by the finite-element method (FEM) with a perfectly matched layer as the boundary condition. The optimized HS-PCF has a dispersion coefficient of $-601.67\;ps\;nm^{-1}\;km^{-1}$ and a high birefringence of $1.025{\times}10^{-2}$ at $1.55{\mu}m$. In addition, over the S+C+L+U wavelength bands the proposed HS-PCF with ultraflat birefringence with a slope on the order of $10^{-5}$.