• Journal of the Korean Chemical Society
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• v.44 no.5
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• pp.415-421
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• 2000

Volatile organic compounds(VOCs) emitted from PC/Monitor set and chemical parts com-prising of PC/Monitor set were analyzed aran, and xylene of VOCs based on qualitative analysis. As a result of these analyses, when the Wedge Rub-ber of rubber product was heated from 60$^{\circ}C$ to 80$^{\circ}C$, the emission rate(%) of xylene was increased about 2.5 times. But it was evaluated that the left of chemical parts were not affected by temperature except Wedge Rub-ber. The results of qualitative analyses between RGA and GC-MS were a little different respectively. With quantitative analysis, concentration of xylene emitted from cabinet was measured to be maximum as 6029.3 ug/ m$^3$(1.3ppm). The concentrations of toluene, xylene, and benzofuran derived from PC/Monitor set were 10.25${\mu}g/m^3$, 690${\mu}g/m^3$, and 180 ${\mu}g/m^3$, and these concentrations were relatively high levels which can bring on the risk to human health.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.974-981
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• 1997

A combined treatment of high hydrostatic pressure and carbonation was used to inactivate pectinesterase (PE) and sterilize microorganisms in Valencia orange juice without major changes in its nutritive components. Quality characteristics of Valencia orange juice, such as microorganisms, PE activity, vitamin C content and color, were evaluated after it was treated with pressure, carbonation-and-pressure, and heat. Quality changes during storage at $4^{\circ}C$ and $30^{\circ}C$ after the treatments were also investigated. Pressurized orange juice (pressurized at 600 MPa for 10 min at $20^{\circ}C$) showed 7.0% residual PE activity, while the carbonated-and-pressurized orange juice (207 $kPa-CO_2$ gas pressure, pressurized at 600 MPa for 10 min at $20^{\circ}C$) showed 0%. Pressurization at 400 MPa or higher decreased the population of microorganisms in the orange juice to less than 10 CFU/mL. Carbonated-and-pressurized orange juice showed slight decrease in vitamin C content when stored at both $4^{\circ}C\;and\;30^{\circ}C$. While heat-treated ($90^{\circ}C$ for 60 sec) orange juice showed 75% decrease in vitamin C content when stored at $30^{\circ}C$. L value (lightness) and b value (yellowness) of carbonated-and-pressurized orange juice were higher than those of heat-treated orange juice when they were stored at $4^{\circ}C$ for 30 days.

• Resources Recycling
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• v.8 no.4
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• pp.45-56
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• 1999

The purpose of tlus sludy was to preparc raw material powder for Mn-Zn iclrile, h m mined mill scale and fero-Mn, usins a co-spray roasting process The mill scale and ferra-Mn uscd in this raalins process was rcf~nedb y mesn-ns of a slxc~apl rxcss ~nvolvinm~a te~ialsc ontalning imp~u-ltleso r less than 100 pprn In this study an effeclive spray roaster system. wllich produces fme complex oxide powder, collects produccd ~owder.,m d prcvel~tse ~~llssiooifi HCI gas. was also manufactured. By means of spray~ngp urifcd raw malerial solu~lionl nln a manufacued high tcmpervture rumace. &-ferrite powder and a comnpleu o ~ d e powder of Fe,O; and M,x203 were manufactured. The chmcterlstics of the composllion. surface urca, and p'miicle size dismbulion or the produced powder were exmined. ptoduced powdcr was then ~ m e dwi tli ZnO powder. aid olher addilives of defined cornposnion, and Mn-Zn femite cares werc praiuccil by meuns of Sorlning and closely controlled sintering processes. The magpelic p~oprlieso f c olo~ss, initlal permeability. mauin~u~mnn agnehc flux. coz~civcr orcc and residual magnccic flux for the above cores we,= measured, and fmm Il~ase I-csulls the eflicacy of lhe co-spray roasling pncess to pl.ellare raw material powder lor Mn-Zn ferntc was established

• Tuberculosis and Respiratory Diseases
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• v.60 no.6
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• pp.631-637
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• 2006

Background: Patients with COPD generally complain of very different degrees of dyspnea regardless of their pulmonary function. The study, we assessed the right ventricular ejection fraction in relation to dyspnea in COPD patient. Methods: The pulmonary function including the diffusion capacity was measured. The right ventricle ejection fraction (RVEF) was measured using a first-pass radionuclide scan by multigated acquisition (MUGA). Forty patients with chronic obstructive pulmonary disease (COPD) were stratified for dyspnea according to the Medical Research Council (MRC) scale. Moderate dyspnea and severe dyspnea is defined as MRC 2/3 (n = 16) and MRC 4/5 (n = 24) respectively. Results: The baseline pulmonary function tests including DLCO and the resting arterial blood gas were similar in the moderate and severe dyspnea group, with the exception of the residual volume (% predicted) (moderate $160{\pm}27$, severe $210{\pm}87$, p < 0.03). The right ventricle ejection fraction was significantly (p < 0.001) lower in the severe dyspnea group ($25{\pm}8$) than in the moderate group ($35{\pm}6$). The independent factor assessed by multiple logistic regression revealed only the severity of dyspnea to be significantly associated with RVEF (p < 0.02). Conclusion: This study showed that the right ventricle ejection fraction would contributes to severity of dyspnea in patients with a similar pulmonary function.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.483-490
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• 2012

Ready-to-eat chicken breasts were packaged in a multilayer, gas-tight tray with top film and various quality changes were investigated during the 24 wk of storage at $10^{\circ}C$. Over the storage period, total aerobes, mesophilic aerobic and anaerobic spore formers, and Clostridium spp. were not detected above 1.0 log CFU/g (detection limit). The residual oxygen ratio in the head space of tray and pH values tended to decrease with storage time, namely from initial values of 5.7% and 6.56 to 3.3% and 6.34 at week 24, respectively. Thiobarbituric acid reactive substances and volatile basic nitrogen values increased from 0.52 mg malonaldehyde (MA)/kg and 2.1 mg/100 g initially, to 3.70 mg MA/kg and 39.9 mg/100 g at week 24, respectively. In terms of the change in meat color during storage, the samples showed a slight increasing trend of CIE $a^*$, $b^*$, and ${\Delta}E$ values over the storage period until week 24 (p<0.05). The change in brine color showed a similar trend with meat of which Hunter $b^*$ and ${\Delta}E$ values increased slightly during storage during 24 wk (p<0.05). The values for the transmittance degree of brine in the samples tended to decrease. Moreover, values for the absorbance degree tended to increase with storage time until week 24. The sensory scores for color, texture, odour, and flavour were evaluated below 5.0 (marketability level) after 24 wk of storage. Based on this sensory evaluation, it could be concluded that retorted RTE chicken breast could remain marketable for at least 20 wk at $10^{\circ}C$.

• Korean Journal of Environmental Agriculture
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• v.40 no.2
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• pp.134-141
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• 2021

BACKGROUND: The analytical method was established for determination of fungicide chinomethionat in several animal commodities using gas chromatography (GC) coupled with electron capture detector (ECD). METHODS AND RESULTS: In order to verify the applicability, the method was optimized for determining chinomethonat in various livestock products including beef, pork, chicken, milk and egg. Chinomethionat residual was extracted using acetone/dichloromethane(9/1, v/v) with magnesium sulfate and sodium chloride (salting outassociated liquid-liquid extraction). The extract was diluted by direct partitioning into dichloromethane to remove polar co-extractives in the aqueous phase. The extract was finally purified with optimized silica gel 10 g. CONCLUSION: The method limit of quantitation (MLOQ) was 0.02 mg/kg, which was in accordance with the maximum residue level (MRL) of chinomathionate as 0.05 mg/kg in livestock product. Recovery tests were carried out at two levels of concentration (MLOQ, 10 MLOQ) and resulted in good recoveries (84.8~103.0%). Reproducibilities were obtained (Coefficient of variation <5.2%), and the linearity of calibration curves were reasonable (r²>0.995) in the range of 0.01-0.2 ㎍/mL. This established analytical method was fully validated and could be useful for quantification of chinomathionat in animal commodities as official analytical method.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.9-13
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• 2022

Bullets flying with a light from the back are called "tracers". Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called "thermoluminescence (TL)". This study aims to compare the TL emission of Dy³⁺, La³⁺ and Ho³⁺ doped MgB₄O₇ phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB₄O₇. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy³⁺, La³⁺ and Ho³⁺ (at different concentrations of 5, 10, 15 and 20 %) doped MgB₄O₇ were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

• Analytical Science and Technology
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• v.21 no.6
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• pp.443-458
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• 2008

Brominated flame retardants (BFRs) are chemical compounds that inhibit the combustion of organic materials by scavenging free radicals that would otherwise encourage the spread of flames. These compounds are found in a wide variety of materials including paints, plastics, textiles, furniture and electronics. Mounting evidence, however, suggests that the non-reactive BFRs can easily leach into the environment and pose significant environmental and health concerns. PBDDs/PBDFs are often formed in the process of manufacturing brominated flame retardants and from the combustion of waste products containing flame retardants BFR. Therefore, this paper describes the general characteristics, management status, residual concentration in environments and analytical method.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.379-388
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• 1994

Background : In sleep apnea syndrome, arterial oxygen saturation($SaO_2$) decreases at a variable rate and to a variable degree for a given apneic period from patient to patient, and various kinds of cardiac arrythmia are known to occur. Factors supposed to affect arterial oxygen desaturation during apnea are duration of apnea, lung voulume at which apnea occurs, and oxygen consumption rate of the subject. The lung serves as preferential oxygen source during apnea, and there have been many reports related with the influence of lung volume on $SaO_2$ during apnea, but there are few, if any, studies about the influence of oxygen consumption rate of an individual on $SaO_2$ during breath holding or about the profile of arterial oxygen resaturation after breathing resumed. Methods : To investigate the changes of $SaO_2$ and heart rate(HR) during breath holding(BH) and rebreathing(RB) and to evaluate the physiologic factors responsible for the changes, lung volume measurements, and arterial blood gas analyses were performed in 17 healthy subjects. Nasal airflow by thermistor, $SaO_2$ by pulse oxymeter and ECG tracing were recorded on Polygraph(TA 4000, Gould, U.S.A.) during voluntary BH & RB at total lung capacity(TLC), at functional residual capacity(FRC) and at residual volume(RV), respectively, for the study subjects. Each subject's basal metabolic rate(BMR) was assumed on Harris-Benedict equation. Results: The time needed for $SaO_2$ to drop 2% from the basal level during breath holding(T2%) were $70.1{\pm}14.2$ sec(mean${\pm}$standard deviation) at TLC, $44.0{\pm}11.6$ sec at FRC, and $33.2{\pm}11.1$ sec at RV(TLC vs. FRC, p<0.05; FRC vs. RV, p<0.05). On rebreathing after $SaO_2$ decreased 2%, further decrement in $SaO_2$ was observed and it was significantly greater at RV($4.3{\pm}2.1%$) than at TLC($1.4{\pm}1.0%$)(p<0.05) or at FRC($1.9{\pm}1.4%$)(p<0.05). The time required for $SaO_2$ to return to the basal level after RB(Tr) at TLC was not significantly different from those at FRC or at RV. T2% had no significant correlation either with lung volumes or with BMR respectively. On the other hand, T2% had significant correlation with TLC/BMR(r=0.693, p<0.01) and FRC/BMR (r=0.615, p<0.025) but not with RV/BMR(r=0.227, p>0.05). The differences between maximal and minimal HR(${\Delta}HR$) during the BH-RB manuever were $27.5{\pm}9.2/min$ at TLC, $26.4{\pm}14.0/min$ at RV, and $19.1{\pm}6.0/min$ at FRC which was significantly smaller than those at TLC(p<0.05) or at RV(p<0.05). The mean difference of 5 p-p intervals before and after RB were $0.8{\pm}0.10$ sec and $0.72{\pm}0.09$ sec at TLC(p<0.001), $0.82{\pm}0.11$ sec and $0.73{\pm}0.09$ sec at FRC(p<0.025), and $0.77{\pm}0.09$ sec and $0.72{\pm}0.09$ sec at RV(p<0.05). Conclusion Healthy subjects showed arterial desaturation of various rates and extent during breath holding at different lung volumes. When breath held at lung volume greater than FRC, the rate of arterial desaturation significantly correlated with lung volume/basal metabolic rate, but when breath held at RV, the rate of arterial desaturation did not correlate linearly with RV/BMR. Sinus arrythmias occurred during breath holding and rebreathing manuever irrespective of the size of the lung volume at which breath holding started, and the amount of change was smallest when breath held at FRC and the change in vagal tone induced by alteration in respiratory movement might be the major responsible factor for the sinus arrythmia.

• Food Science and Preservation
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• v.16 no.6
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• pp.810-816
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• 2009

To identify effective food packaging compounds that could significantly affect the freshness of stored food, the efficiency and performance of porous polypropylene film containing mustard oil as a freshness maintenance ingredient was studied by GC-MS analysis and storage testing of bread. AITC (allyl-isothiocyanate)-emitting properties of films impregnated with mustard oil were evaluated by GC-MS. AITC was extracted from mustard oil, and used as a vapor as an effective antimicrobial agent. Films were prepared under four different conditions (the film types were abbreviated 25SF1, 25SF2, 50LF, and IAF) and the amounts of AITC inside vinyl packs constructed using the four films were measured. The results showed that the 25SF2 film (width 25 mm, length 20 cm) yielded a greater amount of AITC than did the 50LF film (width 50 mm, length 20 cm). We confirmed that the amount of gas emission showed better between layer and layer of the film side than the internal film. In storage testing using various films at $35^{\circ}C$ for 25 days, 25SF2 film provided excellent preservation of bread compared with 50LF film. This was in line with the fact that 25SF2 film yielded the highest amount of AITC. Emission capacities AITC of 2 cm film were measured using bottles various volumes (43 mL, 500 mL, 1000 mL) and both closed and open systems. The AITC content of the film in 43 mL bottle was much higher than that yielded by other films in the closed system, and AITC was rapidly emitted, with relatively low residual gas emission after 4 days in an open system. Mustard oil is a useful freshness maintenance ingredient hence, analysis of AITC emission kinetics from various films were helpful to develop films with optimal antimicrobial effects, and will allow application of such films in food packaging systems.