• 마이크로전자및패키징학회지
• /
• 제10권2호
• /
• pp.13-17
• /
• 2003

본 연구에서는 $ZnWO_4-LiF$계를 이용하여 RF모듈 구현을 위한 새로운 조성의 LTCC 소재를 개발하고자 하였다. 순수 $ZnWO_4$의 경우 98% 이상의 상대밀도를 얻기 위해서는 $1050^{\circ}C$이상의 소결온도가 필요하였고 소결체의 고주파유전특성은 유전율($\epsilon_r$) 15.5, 품질계수($Q{\times}f0$) 74000 GHz, 공진주파수 온도계수$(\tau_f)-70ppm/^{\circ}C$이었다. $ZnWO_4$에 LiF의 첨가는 상호 반응에 의해 $810^{\circ}C$ 부근에서 액상을 형성하였고 따라서 0.5에서 1.5 wt%의 LiF의 첨가로 $ZnWO_4$를 $820^{\circ}C$에서 치밀화를 얻을 수 있었다. 주어진 LiF의 첨가범위에서 소결 수축률은 LiF 량의 증가와 함께 증가하였다. LiF의 첨가는 LiF 자체의 낮은 유전율에 의해 유전율을 15.5에서 14.2∼15의 범위로 감소시켰으며 품질계수($Q{\times}f0$)도 LiF와 $ZnWO_4$의 반응 및 미세구조의 불균일화로 LiF의 첨가량의 증가와 함께 낮아지는 경향을 보였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권2호
• /
• pp.116-122
• /
• 2004

A micromachined self-exited piezoelectric cantilever has been fabricated using PZT(52/48) thin film. For the application to biosensor using antigen-antibody interaction, electromechanical properties such as resonant frequency and quality factor of micromachined piezoelectric cantilever were important factors. Electromechanical properties and resonant behaviors of microfabricated cantilever were simulated by FEA (Finite Element Analysis) using Coventorware$^{TM}$2003. And these characterization of microcantilever were measured by using LDV(Laser Doppler Vibrometer) to compare with FEA data. We present the resonant frequency shift of micromachined piezoelectric cantilevers due to combination of mass loading and change of spring constant by gold deposition. Experimental mass sensitivities of microcantilever were characterized by Au deposition on the backside of microcantilever. Mass sensitivities with $100{\times}300$ ${\mu}{\textrm}{m}$ dimension cantilever from simulation and experimental were 5.56 Hz/ng and 16.8 Hz/ng respectively.y.

• 한국환경과학회지
• /
• 제22권8호
• /
• pp.1009-1017
• /
• 2013

Perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS) is a new persistent organic pollutants of substantial environmental concern. This study investigated the potential of magnetic ion exchange resin (MIEX$^{(R)}$) as the adsorbent for the removal of PFOA and PFOS from Nakdong River water. In our batch experiments, we studied the effect of some parameters (pH, temperature, sulfate concentration) on the removal of PFOA and PFOS. The results of sorption kinetics on MIEX$^{(R)}$ show that it takes 90 min to reach equilibrium but the economical contact time and dosage were 30 min and 10 mL/L. An increase in pH (pH 6~10) leads to a decrease in PFOA (2.0%) and PFOS (3.6%) sorption on MIEX$^{(R)}$. The sorption of both PFOA and PFOS decreases with an increase in ionic strength for sulfate ion (${SO_4}^{2-}$), due to the competition phenomenon. An increase in water temperature ($8^{\circ}C{\sim}28^{\circ}C$) in water leads to a increase in PFOA (2.8%) and PFOS (4.3%) sorption on MIEX$^{(R)}$. Based on the sorption behaviors and characteristics of the adsorbents and adsorbates, ion exchange and hydrophobic interaction were deduced to be involved in the sorption, and hemi-micelles possibly formed in the intraparticle pores.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권2호
• /
• pp.282-289
• /
• 2019

Objective: This study aimed to elucidate whether innovative sous vide treatment has a significant influence on the beef semitendinosus muscle as compared to common sous vide treatment and traditional cooking. Methods: The innovative sous vide treatments were cooked at $45^{\circ}C$ and $65^{\circ}C$ for 6 h (SV45-65), common sous vide treatment at $45^{\circ}C$ and $65^{\circ}C$ for 3 h (SV45 and SV65) and traditional cooking at $75^{\circ}C$ for 30 min (CON75). Water loss and cooking loss, as well as the physical properties (color and shear force) and chemical properties (protein and collagen solubility) of the treated meat, were investigated. Results: The results obtained indicated that the innovative sous vide with double thermal treatment (SV45-65) and cooked with air presence (CON75) resulted to lower $a^*$ and higher $b^*$ values, respectively. The water loss and cooking loss increased when temperature increased from $45^{\circ}C$ to $65^{\circ}C$, and lower water loss was recorded in SV45 and CON75. These samples presented higher water content and revealed strong correlation to protein solubility. Warner-Bratzler shear force (SF) analysis showed the marked interaction between cooking temperature and time. Sample cooked at a high temperature (CON75) and a long period (SV45-65) showed a significantly lower value of SF than sample SV65 (p<0.05). Interestingly, there was no difference in SF values between SV45-65 and CON75. Conclusion: The innovative sous vide treatment with double thermal effect appears an attractive cooking method as compared to common sous vide and traditional cooking method, as it has a potential for improving tenderness values of cooked beef semitendinosus muscle.

• Bulletin of the Korean Chemical Society
• /
• 제30권12호
• /
• pp.2962-2968
• /
• 2009

The photodissociation dynamics of 1,2-bromochloroethane ($C_2H_4BrCl$) was investigated near 234 nm. A two-dimensional photofragment ion-imaging technique coupled with a [2+1] resonance-enhanced multiphoton ionization scheme was utilized to obtain speed and angular distributions of the nascent Br($^2P_{3/2}$) and Br${\ast}($^2P_{1/2}$) atoms. The total translational energy distributions for the Br and Br${\ast}$ channels were well characterized by Gaussian functions with average translational energies of 100 and 84 kJ/mol, respectively. The recoil anisotropies for the Br and Br${\ast}$ channels were measured to be ${\beta}$ = 0.49 ${\pm}$ 0.05 for Br and 1.55 ${\pm}$ 0.05 for Br${\ast}$. The relative quantum yield for Br${\ast}$ was found to be ${\Phi}_{Br{\ast}}$ = 0.33 ${\pm}$ 0.03. The probability of nonadiabatic transition between A' states was estimated to be 0.46. The relevant nonadiabatic dynamics is discussed in terms of interaction between potential energy surfaces in Cs symmetry.

• Asian-Australasian Journal of Animal Sciences
• /
• 제26권2호
• /
• pp.275-281
• /
• 2013

The objective of this study was to determine the effect of slaughter season on the fatty acid profile in four types of fat deposits in crossbred (Polish Holstein Friesian Black-and-White${\times}$Limousine) beef bulls. The percentage share of fatty acids was determined by gas chromatography and were divided into the following categories of fatty acids: saturated (SFAs), unsaturated (UFAs), monounsaturated (MUFAs), polyunsaturated (PUFAs), desirable hypocholesterolemic (DFAs) and undesirable hypercholesterolemic (OFAs), n-3 and n-6. Perinephric fat was characterized by the highest SFA concentrations (59.89%), and subcutaneous fat had the highest MUFA content (50.63%). Intramuscular fat was marked by a high percentage share of PUFAs and the highest PUFA/SFA ratio. The slaughter season had a significant effect on the levels of C18:3, C20:4 ($p{\leq}0.01$) and conjugated linoleic acid ($p{\leq}0.05$). There was an interaction between the slaughter season and fat type for the content of C20:4 ($p{\leq}0.01$) and C20:5 ($p{\leq}0.05$). The results of this study show that beef from cattle slaughtered in the summer season has a higher nutritional value and more health-promoting properties.

• Journal of Ecology and Environment
• /
• 제42권1호
• /
• pp.1-11
• /
• 2018

Background: In the study, the effects of elevated $CO_2$ and temperature on the nitrogen content, carbon content, and C:N ratio of seven rare and endangered species (Quercus gilva, Hibiscus hambo, Paliurus ramosissimus, Cicuta virosa, Bupleurum latissimum, Viola raddeana, and Iris dichotoma) were examined under control (ambient $CO_2$ + ambient temperature) and treatment (elevated $CO_2$ + elevated temperature) for 3 years (May 2008 and June 2011). Results: Elevated $CO_2$ concentration and temperature result in a decline in leaf nitrogen content for three woody species in May 2009 and June 2011, while four herb species showed different responses to each other. The nitrogen content of B. latissimum and I. dichotoma decreased under treatment in either 2009 and 2011. The leaf nitrogen content of C. virosa and V. raddeana was not significantly affected by elevated $CO_2$ and temperature in 2009, but that of C. virosa increased and that V. raddeana decreased under the treatment in 2011. In 2009, it was found that there was no difference in carbon content in the leaves of the six species except for that of P. ramosissimus. On the other hand, while there was no difference in carbon content in the leaves of Q. gilva in the control and treatment in 2011, carbon content in the leaves of the remaining six species increased due to the rise of $CO_2$ concentration and temperature. The C:N ratio in the leaf of C. virosa grown in the treatment was lower in both 2009 and 2011 than that in the control. The C:N ratio in the leaf of V. raddeana decreased by 16.4% from the previous year, but increased by 28.9% in 2011. For the other five species, C:N ratios increased both in 2009 and 2011. In 2009 and 2011, chlorophyll contents in the leaves of Q. gilva and H. hamabo were higher in the treatment than those in the control. In the case of P. ramosissimus, the ratio was higher in the treatment than that in the control in 2009, but in 2011, the result was the opposite. Among four herb species, the chlorophyll contents in the leaves of C. virosa, V. raddeana, and I. dichotoma did not show any difference between gradients in 2009, but decreased due to the rise of $CO_2$ concentration and temperature in 2011. Leaf nitrogen and carbon contents, C:N ratio, and chlorophyll contents in the leaves of seven rare and endangered species of plant were found to be influenced by the rise and duration of $CO_2$ concentration and temperature, species, and interaction among those factors. Conclusions: The findings above seem to show that long-term rise of $CO_2$ concentration, and temperature causes changes in physiological responses of rare and endangered species of plant and the responses may be species-specific. In particular, woody species seem to be more sensitive to the rise of $CO_2$ concentration and temperature than herb species.

• Asian-Australasian Journal of Animal Sciences
• /
• 제13권6호
• /
• pp.830-836
• /
• 2000

A participation scheme involving smallholder dairy farmers in improving dairy productivity through the use of local feeds, on-farm established feeds and crop residues was carried out in the Northeast, Thailand. At six milk collection centers, 63 farmers with 340 lactating cows participated in this research and demonstration of feed supplements. Farmers and cows were allotted to receive respective feed supplements: high-quality feed block (HQFB), high-quality feed pellet (HQFP), dried cassava leaf/cassava hay, dried leucaena leaf and cottonseed meal: 5% urea treated rice straw was fed as a source of roughage throughout the feeding period of the dry season. Trainings and workshops were organized by the researchers at the University, research station, demonstration sites and on-farms. Regular visits to the fartns by researchers and extension officers were made while discussions and demonstrations were performed in addition. Participating farmers also visited other farmers during the demonstration which offered a real practical perspective and farmer-to-farmer interaction. As a result of this participation and demonstration scheme, the farmers could learn more effectively and accepted the technology more readily, especially the practicality of the feed preparation, feed establishment, feeding method and feed reserve. Strategic supplementation of these feed supplements resulted in improving milk yield, milk quality, overall condition of the cows and higher income return through increased productivity and lower level use of concentrate to milk yield from 1:2 to 1:3 or lower. Based on this research and demonstration /participation scheme, all feed supplements enhanced productivity, however the establishment of cassava hay on fartns deserved more attention and warrants a wider developmental expansion among dairy farmers since it contained high rumen by-pass protein (tannin-protein complex) and could be easily produced and be sustainable on farms.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권1호
• /
• pp.21-25
• /
• 2013

Background: Genetic factors and environmental factors play a role in pathogenesis of esophageal squamous cell carcinoma (ESCC). Previous studies regarding the association of folate intake and Methylenetetrahydrofolate reductase C677T polymorphism with ESCC was conflicting. We conducted a meta-analysis to investigate the association of MTHFR C677T and folate intake with esophageal cancer risk. Methods: MEDLINE, EMBASE and the Chinese Biomedical Database were searched in our study. The quality of studies were evaluated by predefined scale, and The association of polymorphisms of MTHFR C677T and folate intake and ESCC risk was estimated by Odds ratio (ORs) with 95% confidence intervals (CIs). Results: 19 studies (4239 cases and 5575 controls) were included for meta-analysis. A significant association was seen between individuals with MTHFR 677 CT [OR(95%)=1.47(1.32-1.63)] and TT [OR(95%)=1.69(1.49-1.91)] genotypes and ESCC risk (p<0.05). Low intake of folate had significantly higher risk of esophageal cancer among individuals with CT/TT genotype [OR(95%)=1.65(1.1-2.49)], while high intake of folate did not find significant high risk of esophageal cancer among individuals with CT/TT genotype [OR(95%)=1.64 (0.82-3.26)]. Conclusions: Our meta-analysis indicated the folate intake and MTHFR 677CT/TT are associated with the risk of ESCC, and folate showed a significant interaction with polymorphism of MTHFR C677T.

• 한국건축시공학회지
• /
• 제13권5호
• /
• pp.457-464
• /
• 2013

Traditionally, the material used for the form in reinforced concrete construction has been wood or steel. But recently, aluminum forms have been widely used in wall structures such as apartment buildings. Aluminum is light, easy to handle, and economically advantageous, but the hydrogen gas created due to its reaction with the alkali component in concrete gives rise to air pockets on the concrete's surface, and deteriorates the surface's finishability. In this research, to determine the influence of aluminum material on concrete, the cement paste W/C and its chemical reactivity in alkali and acid solution were analyzed. As a prevention plan, the influence of the number of applications of calcium hydroxide and various surface coating materials was analyzed. Through the analysis, it was found that the surface voids on the aluminum form are the result of the reaction of hydrogen gas with an alkali such as $Ca(OH)_2$. This can be prevented by the surface treatment of $Ca(OH)_2$, separating material and coating material. However, poor surface form and damages to the form are expected to cause quality degradation because of the aluminum-concrete interaction. Therefore, thorough surface treatment, rather than the type of separating material or coating material, is considered the most important target of management.