• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.310-317
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• 1990

An experiment was conducted to investigate the effects of adding extra dietary salt on the blood acid－base balance, water intake and egg quality in heat stressed layers. Eighteen 44－wk－old brown commercial layers(Dekalb Warren) were randomly alloted to 0.25 and 0.75% dietary salt treatments, with nine replicates per treatment and one bird per replicate. After 3 d of preliminary period at 13~$16^{\circ}C$(normal temperature), layers were subjected to 3 d of collection period. Then the room temperature was raised to 33－$35^{\circ}C$f(hot temperature), and another 3 d of collodion period was followed. The experiment was designed as a $2\times2$ factorial and analyzed as suck The ANOVA test and comparison among treatment means were done at 5% probability levels. Results obtained were summarized as follows. L The heat stressed layers decreased feed intake, and increased water intake and excreta moisture content significantly. The addition of extradietary salt significantly increased excreta moisture content 2. The heat stressed layers showed significantly higher blood pH and lower $pCO_2$ values than the control bird However, the addition of extra salt did not change any acid－base variables. 3. The egg weight and shell quality decreased significantly, and haugh unit increased significantly by the heat stress. However, these values were not affected by the salt addition. In summary, the heat stressed layers displayed respiratory alkalosis and poor egg quality, as expected However, the addition of ex03 salt to the diet failed to alleviated the heat stress in this layer experiment.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.419-424
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• 1994

An oil stain on the steel induced by metal working oil was studied on the six kinds of fat and oil compounds(rapeseed oil, oleic acid, methyl oleate, oleyl alcohol, lauryl amino, and lanolin) by MIL-C-22235A test. The samples used for the printing on the oil stain plates were prepared by the addition of fat and oil compounds(10wt% ) and antioxidants(B. H. T, B. T, T. C. P; 0.5wt%) to base oil(spindle oil; 1.5wt% of sulfur). An analysis based on the experimental data indicated that B.T was more effective than B. H. T and T. C. P as antioxidant for inhibiting oil stains. And acid values exerted a bad influence upon the preventation of oil stains. As expected by the chemical structure of fat and oil compound, oleic acid that could react with iron ions produced more stains on the steel pannel.

• Journal of the Korean Chemical Society
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• v.63 no.5
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• pp.376-386
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• 2019

The purpose of this study was to explore the learning progression of logical thinking in acid and base chemical reactions and to evaluate its validity. For this purpose, we collected 387 participants in 9 schools of elementary, middle and high schools nationwide. The questionnaire developed in this study was composed of nine items. The questionnaire presented the acid and base reactants and products, and the students pictured their thoughts on how these substances change, and answered the reasons of their thoughts. Situation contexts of the questionnaire were divided into two groups: one kind of solute dissolved in a solvent, and two kinds of solute dissolved in a solvent. In this study, six levels of learning progression were assumed by combining material conservation logic, combination logic, proportion logic, and particle number conservation logic. By analyzing the data, Infit and Outfit values of Person reliability, Item reliability, MNSQ and ZSTD were obtained from the Rasch model. As a result of the analysis of data, it was found that lower levels of learning progression prevailed up to the younger grade students till $8^{th}$ grade. The higher levels of learning progression(Level 2~Level 5) prevailed up to the older grade students. However, higher levels of learning progression dropped sharply in Grade 12. The 5 level of learning progression was very low in all grades, and $9^{th}$ grade had highest percentage of students belonging to the 5 level. Interpretation of these unusual results suggests a future research related to explanation differences of textbooks.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.358-364
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• 2019

To improve the optical characteristics and antifouling of anti-reflective coating (AR) films, various AR coating films were prepared by varying the mixing ratio of tetraethylorthosilicate (TEOS)/base and methyltrimethoxysilane (MTMS)/acid hybrid solution. Prepared AR coating films were characterized by UV-Vis spectroscopy, contact angle analyzer, atomic force microscope (AFM), FT-IR and pencil scratch hardness test. In an AR coating film that prepared from the hybrid solution with a 10 wt% MTMS/acid solution, the glass substrate showed an excellent optical property (97.2% transmittance), good antifouling ($121^{\circ}$ water contact angle and $90^{\circ}\;CH_2I_2$ contact angle) and moderate mechanical strength (pencil hardness of 4 H). In particular, it is considered that the good antifouling was due to the well dispersion of the methyl group ($-CH_3$), derived from a small amount of MTMS/acid solution in the hybrid solution, on the substrate surface. From results of the pencil hardness test, the mechanical strength of AR coating film was improved as the content of MTMS/acid solution increased.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.87-94
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• 2004

The effects of pretreatment of GAC and dissolved oxygen (DO) on the sorption capacity for ο-cresol were investigated using pretreated GAC under oxic and anoxic conditions. Virgin GAC was used with pretreated GACs by $O_2$, acid and base as sorbents. Sorption capacity of GAC was dependent on the oxygen conditions according to the pretreatment methods. Virgin GAC showed increased sorption capacity when DO was present in the solution, while $O_2$-pretreated GAC did not show any considerable capacity change. Acid- and base-pretreated GACs were relatively more influenced by presence of DO as compared with virgin GAC. Both acid and base-pretreated GACs showed a rapid sorption rate at the initial stage, but as contact time became longer the sorption was slower. Sorbed ο-cresol was extracted with micro-Soxhlet extraction apparatus using the GAC separated from the rate experiments. Within 1 hour both acid and base-pretreated GACs showed the decrease in extraction efficiencies under both oxic and anoxic conditions. After 1 hour such a trend (the increase as contact time was longer) was not observed and showed relatively constant efficiencies of 35∼50%. According to the results of this study $O_2$contacted with GAC before sorption as well as DO present in the solution during sorption could influence the GAC sorption capacity.

• Polymer(Korea)
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• v.36 no.5
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• pp.612-616
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• 2012

In this work, the effect of chemical treatments of multi-walled carbon nanotubes (MWNTs) on the mechanical interfacial properties of carbon fiber fabric-reinforced composites was investigated. The surface properties of the MWNTs were determined by acid and base values, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses. The mechanical interfacial properties of the composites were assessed by interlaminar shear stress (ILSS) and critical stress intensity factor ($K_{IC}$). The chemical treatments based on acid and base reactions led to a significant change of surface characteristics of the MWNTs, especially A-MWNTs/carbon fibers/epoxy composites had higher mechanical properties than those of B-MWNTs and non-treated MWNTs/carbon fibers/epoxy composites. These results were probably due to the improvement of interfacial bonding strength, resulting from the acid-base interaction and hydrogen bonding between the epoxy resins and the MWNT fillers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.433-440
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• 2016

Composite membranes were prepared by the solution casting method from sulfonated poly(etheretherketone)(sPEEK) and imidazole and phosphotungstic acid(PWA) to enhance the electrolytic properties of the membrane. TGA measurements showed that physical crosslinking due to acid-base interactions improved the thermal resistance to the desulfonation of sulfonic acid groups of the composite membrane and the addition of PWA enhanced the resistance to thermal decomposition of the composite membrane. The acid-base interaction decreased the water uptake, proton conductivity and methanol permeability of the sPEEK/imidazole composite membranes. The addition of PWA increased the proton conductivities while it decreased the water uptake and methanol permeability of sPEEK/imidazole/PWA composite membranes. Therefore, the selectivity of the composite membranes was enhanced by the addition of PWA.

• Corrosion Science and Technology
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• v.14 no.2
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• pp.47-53
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• 2015

Recently, the bending process is greatly applied to fabricate the pipe line. Bending process can reduce welding joints and then decrease the number of inspection. Thus, the maintenance cost will be reduced. Induction heat bending process is composed of bending deformation by repeated local heat and cooling. By this thermal process, corrosion properties and microstructure can be affected. This work focused on the effect of induction heating bending process on the properties of ASME SA106 Gr. C low carbon steel pipes. Microstructure analysis, hardness measurements, and immersion corrosion test were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. Hardness was measured using a Rockwell B scale. Induction heat bending process has influenced upon the size and distribution of ferrite and pearlite phases which were transformed into finer structure than those of base metal. Even though the fine microstructure, every bent area showed a little lower hardness than that of base metal. It is considered that softening by the bending process may be arisen. Except of I2, intrados area, the others showed a similar corrosion rate to that of base metal. But even relatively high rate of intrados area was very low and acceptable. Therefore, it is judged that induction heat bending process didn't affect boric acid corrosion behaviour of carbon steel.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.985-993
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• 1997

The effects of CaO and MgO fluxes on the fusibility of fly-ashes were investigated for two different fly-ashes. A fusion temperature of mixtures of selected fly-ashes and fluxes were measured by the ASTM test method(D1857) and the differential thermal analysis. IDT of these samples added CaO and MgO as a fluxing agent dropped in the range of 114 to $294^{\circ}C$ and 80 to $224^{\circ}C$, respectively. Compared with ash fusion temperature to Base/Acid ratio, the lowest ash fusion temperature were measured in the range of 0.7 to 0.8 for CaO-fly ash mixtures and 0.3 to 0.4 for MgO-fly ash mixtures. As a result, MgO in small addition acted as a more effective flux than CaO. A conventional Base/Acid ratio and liquidus point of ternary diagram did not show a good correlation with ash fusion temperature for these samples. In pure fusion temperature of fly ash-mixtures, DTA was better method than ASTM test method.

• Journal of the Korean Chemical Society
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• v.64 no.1
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• pp.19-29
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• 2020

We analyzed the representations of acid-base models in 4 kinds of Chemistry I and 4 kinds of Chemistry II textbooks of the 2009 revised curriculum, and 9 kinds of Chemistry I textbooks and 6 kinds of chemistry II textbooks of the 2015 revised curriculum in this study. The problems of the textbook were divided into the problems of definitions and the representations of the logical thinking. As a result of the study, the lack of the concept of chemical equilibrium had a problem with the representation of reversible reactions in the definition of the Brønsted-Lowry model in the Chemistry I textbooks of 2009 revised curriculum, it also appeared to persist in Chemistry I textbooks of 2015 revised curriculum which contains the concept of chemical equilibrium. The representations of logical thinking were related to particle kinds of conservation logic, combinational logic, particle number conservation logic, and proportion logic. There were few problems related to representation of logical thinking in Chemistry I textbook in 2009 revision curriculum, but more problems of representations related to logics are presented in Chemistry I textbooks in 2015 revision curriculum. Therefore, as the curriculum is revised, the representations of chemistry textbooks related to acid and base models need to be changed in a way that can help students' understanding.