• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.389-400
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• 2013

Little investigations have been carried out to study the shear behaviors of RC beams with recycled aggregates. So, this experiment investigates the shear performance and suggests the possible application of Recycled Concrete Aggregate (RCA) for building structures. In general, shear strength of reinforced concrete beam without stirrups is dependent on the compressive strength of concrete, the longitudinal steel ratio, and the shear span-to-depth ratio. In this study, total 28 recycled aggregate concrete beams without shear reinforcement were tested by two-point load and all beams were singly reinforced. The variables studied in this investigation are shear span-to-depth ratios (a/d=2, 3 and 4), RCA replacement ratios (0, 15, 30 and 50%) and longitudinal steel ratios (0.80, 1.27 and 1.84%). The designed concrete compressive strength with a 30 MPa is used. This research will play an important role toward the establishment of the structural design standard for RCA concrete.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.12 s.148
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• pp.1546-1553
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• 2005

The wetting behavior and liquid transport of nonionic surfactant solutions; Span 20 and Tween 20, 40, 60, 80, 21, 61, 81, 65 & 85: in polyethylene terephthalate(PET) fabrics are reported. Five different PET fabrics are used in this study. PET 1, 2 & 3 have different compactness in structure. PET 4 & 5 have similar physical properties to PET 2, however, PET 4 has heat set finish and PET 5 with rewetting agent. The wetting and water retention properties of PET fabrics are greatly improved by addition of nonionic surfactants. The aqueous liquid retention(W) vs. cosq and W vs. adhesion tension has positive linear relationship. Hydrophilic surfactants which have short hydrophobes and surfactants with unsaturated hydrophobe structures are more efffctive in improving the wetting properties of PET fabrics. PET fabric which has larger thread spacing shows greater value of water retention ratio(W/H) than PET fabric with smaller thread spacing if there are no surfactants present in the system, however, W/H values become very similar among these PET fabrics when the surfactants are added. If there are no surfactants present in the system, PET with heat set finish has smaller value and PET with rewetting agent has greater value of W/H than PET without finish even though the fabrics have the similar physical properties.

• Journal of radiological science and technology
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• v.13 no.2
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• pp.31-36
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• 1990

We got the following results from the experiment and examination in order to measure the bone-marrow dose of the patients when we did chest or abdomen radiography in the hospitals located in Seoul City from Jan. 1989 until Feb. 1990. 1. In the exposure factors for chest radiography, tube voltage $60{\sim}69\;kVp$ took 48.3%, $80{\sim}89\;or\;90{\sim}99\;kVp$ took 13.8% respectively, $70{\sim}79\;kVp$ 10.3% and $100{\sim}129\;kVp$ 10.3%. In tube current and exposure times, $6{\sim}10\;mAs$ took 41.4%, $16{\sim}20\;mAs$ took 20.7% and $11{\sim}15\;mAs$ 13.8%, measure under 5mAs 10.4% orderly. 2. In chest radiography, the bone-marrow dose came to the minimum 3.48 mrad, to the maximum 35.67 mrad, to the mean 14.46 mrad, to the standard deviation 8.89 mrad. 3. Comparing bone-marrow doses of the patients when we used Bucky technique and non-Bucky technique, that of Bucky technique was very higher than that of non-Bucky technique. Because the result was that Bucky technique had the span of $6.09{\sim}35.67$ mrad, while non-Bucky technique had the span of $3.48{\sim}17.40$ mrad. 4. In the exposure factors for abdomen radiography, tube voltage of $70{\sim}79\;kVp$ was 63.0%, that of $80{\sim}89\;kVp$ was 22.2%, that of $60{\sim}69\;kVp$ was 11.1 %. Tube current and exposure times of $31{\sim}40\;kVp$ was 33.4%, that of $51{\sim}60\;mAs$ was 29.6% and that of $41{\sim}50\;mAs$ was 22.2%. 5. In abdomen radiography, the bone-marrow dose of the patients came to the minimum of 6.96 mrad, to the maximum of 60.90 mrad, to the mean of 35.73mrad, to the standard deviation of 12.65 mrad.

• Journal of Preventive Medicine and Public Health
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• v.28 no.1 s.49
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• pp.175-185
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• 1995

To evaluate the neurobehavioral effects of blood lead, we performed NCTB (Neurobehavioral Core Test Battery) on 59 men who were exposed to lead occupationally. Performance on the tests was studied in relation to three ranges of blood lead $(low,\;0. Workers with high and medium blood lead concentrations showed poorer performances on digit span backward, digit symbol and Benton Visual Retention. After adjustment for age and education, high and medium group showed significantly impaired performance on Benton visual retention and slightly impaired performance on digit span backward. But it showed no different performance on tests between high and medium blood lead group.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.201-207
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• 2009

The hydrogenation reaction of methyl dodecanoate for the synthesis of 1-dodecanol has been carried out in the presence of a copper chromite catalyst. The catalysts were synthesized by ceramic method, co-precipitation, and improved co-precipitation method and the particles were characterized by SEM and XRD. Also, the products of the reaction were assigned by GC, GC/MSD and NMR. The particles synthesized by each method showed (1) a spherical shape with the size of 3.2 to $7.0{\mu}m$, (2) an agglomerated spherical shape with the size of 50 to 500 nm and (3) a spherical shape with smaller particle size, respectively. Especially, in order to control the size of particles, the particles were synthesized in various dispersant solutions as Span 80, polyacrylate, and polyethyleneglycols (PEGs). The particles synthesized in PEG (Mw = 4000) solution showed the smallest particle size of 30 to 50 nm and the regularity of the particle size distribution. Our experimental results elucidated that the activity of catalyst for hydrogenation increases with decreasing the size of catalyst particle. The highest yield of dodecanol in the hydrogenation reaction was 95.5% when copper chromite synthesized in the PEG solution was used as a catalyst in the optimized reaction condition.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.505-509
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• 2000

The kinetic structure of the content of instructions at the unit of 'heart and circulation' in "the common science", which was respectively given by two teachers majored in biology and two teachers majored in earth science was investigated. Concerning of the mean of the fundamental coefficient (B1), the mean of weighted coefficients (B2) and the progression of instruction (P), T4 (B1, 0.14; B2, 0.82; P; 0.86) teacher showed relatively lower kinetic structure and faster progression than those of the others. The other teachers showed a different level of the kinetic structure and progression: T1(B1, 0.21; B2, 0.86; P; 0.79), T2 (B1, 0.02; B2, 0.85; P; 0.80), and T3 (B1, 0.22; B2, 0.83; P; 0.78). T1 teacher who showed the largest total frequency of verbal elements, the great number of sorts of verbal elements and secondary span, had a higher level of the kinetic structure, but T4 teacher showed the lowest level of total frequency of verbal elements, the great number of sorts of verbal elements and secondary span. The main reason why T4 teacher's instruction achieved a lower level of kinetic structure was estimated that he neglected to reorganize teaching materials and he showed a small number of discourse units. In addition, the unit of 'heart and circulation' was less related to T4 teacher's major and T4 teacher had a shorter teaching experience than those of the others. T4 teacher also took charge of only one class, and this did not allow to instruct repeatedly.

• The Korean Journal of Nuclear Medicine
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• v.2 no.1
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• pp.27-41
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• 1968

The ferrokinetics and red cell life spans of the patients with chronic glomerulonephritis were investigated by the double tracing method using radioactive iron ($^{59}Fe$) and chromium ($^{51}Cr$). According to the serum NPN levels, the patients were subdivided into 3 groups: Group 1. 6 patients, had the levels below 40 mg/dl Group 2. 6 patients, had the levels between 41 mg/dl to 80 mg/dl Group 3. 10 patients, had the levels above 80 mg/dl The results were as follows: 1) Red blood cell-, hematocrit- and hemoglobin values were moderately reduced in patients with normal serum NPN levels, while markedly reduced in patients with elevated serum NPN levels. 2) The plasma volume was increased, while the red cell volume was decreased in patients with elevated serum NPN levels, hence, total blood volume was unchanged. 3) The serum iron level was slightly reduced h patients of groups 1 and 2, while was within the normal ranges in patients of group 3. 4) i) In patients with normal serum NPN levels, the plasma iron disappearance rate, red cell iron utilization rate, red cell iron turnover rate, daily red cell iron renewal rate, circulating red cell iron and red cell iron concentration were within the normal ranges, while the plasma iron turnover rate was slightly reduced. ii) In patients with elevated serum NPN levels, the plasma iron disappearance rate was delayed, while the plasma iron turnover rate was within the normal ranges. The red cell iron utilization rate, red cell iron turnover rate and circulating red cell iron were decreased and the period in which the red cell iron utilization rate reachd its peak was delayed in Group 3 patients. The daily red cell iron renewal rate and the red cell iron concentration were unchanged. iii) The mean red cell life span was within the normal ranges in patients with normal serum NPN levels, while was shortened in patients with elevated serum NPN levels.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.914-918
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• 1992

The preferential transport phenomena of neutral cation-anion moieties in neutral macrocycle-facilitated emulsion liquid membrane were described in this study. Emulsion membrane systems consisting of (1) aqueous source phase containing 0.001M $M(NO_3)_2$ (M = $Mn^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Sr^{2+}$, $Cd^{2+}$, $Pb^{2+}$) (2) a toluene membrane containing 0.02M ligand (DB$N_3O_2$, DB18C6) and the surfactant span 80 (sorbitan mono oleate) (3% v/v) and (3) aqueous receiving phase containing $Na_2S_2O_3$ or $NaNO_3$ were studied with respect to the disappearence of metal ions from the source phase as a function of time. Cation transport rates for various two component equimolar mixture of metal ions were determinded. $Cd^{2+}$ was transported higher rates than the other $M^{2+}$ in the mixture solution.

• Polymer(Korea)
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• v.36 no.2
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• pp.177-181
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• 2012

This study presents the preparation of double emulsions in a poly(dimethylsiloxane) (PDMS)-based microfluidic device. To improve the wettability of hydrophilic continuous phase onto a hydrophobic PDMS microchannel, the surface was modified with 3-(trimethoxysilyl) propyl methacrylate (TPM) and then sequentially reacted with acrylic acid monomer solution, which produced selective covalent bonding between acrylic acids and methacrylate groups. For the proof of selective surface modification, tolonium chloride solution was used to identify the modified region and we confirmed that the approach was successfully performed. When water containing 0.5% w/w sodium dodecyl sulfate and 1% w/w Span80 with hexadecane were loaded into the selectively modified microfluidic channels, we can produce stable double emulsion. Based on the spreading coefficients, we predict the morphology of double emulsions. Our proposed method efficiently produces monodisperse double emulsions having 48.5 ${\mu}m$(CV:1.6%) core and 65.1 ${\mu}m$ (CV:1.6%) shell. Furthermore, the multiple emulsions having different numbers of core were easily prepared by simple control of flow rates.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.126-132
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• 2012

Two different feed(bran and swine feed) effect was tested on development of Tenebrio molitor at $25{\pm}5^{\circ}C$, $65{\pm}10%RH$. There was no significant feed effect on larval developmental periods(80.0 ~ 83.7 days), pupal length (18.1 ~ 18.7 mm) and fecundity(44.3 ~ 55.3 eggs) during first two days. However, fecundity was significantly affected by the pupal weight(P < 0.05), such that the number of eggs 172.3, 191.2, 215.0 gradually increased as pupal weight rose from 0.12 g, 0.15 g to 0.18 g, respectively. During the first two weeks of oviposition was 51.8%, which gradually decreased for further days. Longevity was $27.1{\pm}6.9$, $30.1{\pm}7.8$, $27.4{\pm}8.5$ days with increasing pupal weight of 0.12, 0.15, 0.18 g, respectively. Larval densities of 100, 300, 500 and 700 individuals reared in the container ($16{\times}21.5{\times}7cm$) resulted 67.9% of the T. molitor pupation during first three weeks. Pupal weight was decreased $146.9{\pm}6.5$, $142.1{\pm}8.3$, $122.0{\pm}9.6$, $118.5{\pm}5.2mg$ when it was reared at different larval densities of 100, 300, 500 and 700 individuals, respectively in size of($16{\times}21.5{\times}7cm$) rearing container.